Progress 10/01/05 to 09/30/11
Outputs
OUTPUTS: Lines of turkeys were selected long-term (more than 45 generations) for increased egg production (E) or increased 16-week body weight (F) and compared to their corresponding non-selected randombred controls (RBC1 and RlBC2, respectively). Selection was effective in both long-term selected lines but the realized heritability of the selected trait declined with generations of selection in both the E and F lines. Genetic increases in growth rate of the F line were associated with a decline in resistance to several disease organisms including Escherichia coli, Erysipelothrix rhusiopathiae, Pasteurella multocida, Newcastle disease virus, and Bordetella avium. Changes in the immune system of the F line relative to the RBC2 line that were responsible for the decreased disease resistance were identified. Haplotypes of the major histocompatibility complex were identified in the experimental and commercial turkey lines. Selection for increased growth rate in the F line was associated with a decrease in walking ability and this problem was solved by selecting for increased shank width that increased the relative amount of leg bones. Crossing of experimental turkey lines with commercial turkey lines led to the discovery of maternal inheritance of breast muscle morphology. Growth-selected lines of turkeys exhibit undesirable breast muscle morphology at market in that there are giant fibers, reduced extracellular space, and deteriorating fibers, possibly resulting in a condition term soft exudative meat. Long-term selection for increased growth rate in Japanese quail was associated with an increase in smooth muscle tumors. PARTICIPANTS: Dr. Karl E Nestor has been a key collaborator in the work on the genetics of the turkey. Some of the research was done in cooperation with scientists at South Dakota State University and Michigan State University. TARGET AUDIENCES: This research will benefit commpercial poultry producers by further defining mechanisms regulating the growth of poultry and aid in increasing the efficiency of lean meat production. PROJECT MODIFICATIONS: Not relevant to this project.
Impacts
Many of the findings of this study have been applied by commercial turkey breeders resulting in reduced leg problems and an increase in disease resistance. This project has contributed to more efficient turkey production due to improved genetics. An improvement of 0.5 percent in the genetics of commercial turkeys would have a farm value of over 161 million dollars in the United States. The turkey lines have been used by many institutions for physiology and disease resistance studies.
Publications
- Sporer, K.R.B., Chaing, W., Tempelman, R.J., Ernst, C.W., Reed, K.M., Velleman, S.G., and Strasburg, G.M. 2011. Characterization of a 6K oligonucleotide turkey skeletal muscle microarray. Animal genetics 42:75-82.
- Song, Y., McFarland, D.C., and Velleman, S.G. 2011. The role of syndecan-4 side chains in turkey satellite cell growth and development. Dev. Growth Diff. 53:97-109.
- Sporer,K.R.B., Tempelman, R.J., Ernst, C.W., Reed, K.M., Velleman, S.G., and Strasburg, G.M. 2011. Transcriptional profiling identifies differentially expressed genes in developing turkey skeletal muscle. BMC Genomics. 12:143.
- Shin, J., McFarland, D.C., and Velleman, S.G. 2011. The heparan sulfate proteoglycans, syndecan-4 and glypican-1, differentially regulate myogenic regulatory transcription factors and paired box 7 expression during turkey satellite cell myogenesis: Implications for muscle growth. Poult. Sci (in press).
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Progress 01/01/10 to 12/31/10
Outputs
OUTPUTS: Turkey experimental lines E (selected for 44 years for increased total egg production)and F(selected for 38 years for increased 16-week body weight)were mated reciprocally with the random-bred control lines from which they were derived (RBC1 and RBC2, respectively)and pureline and reciprocal cross poults were compared for their body weights, heart weight, heart rates, myocardial glycogen and lactate concentrations and plasma creatine kinase and lactate dehydrogenase activities. The creatine kinase and dehydrogenase activities were used as indicators of cardiac insufficiency. Orthogonal contrasts of the data from pureline and reciprocal cross data were used to estimate additive genetic effects, reciprocal effects (confounded maternal and sex-linked effects)and heterosis for each of the traits measured. Long-term selection for increased egg production in the E line has reduced embryo heart weight and has altered the energy metabolism of the myocardium. The differences in energy metabolism may be due to more rapid heart rates. Conversely, long-term selection for increased 16-week body weight has significantly decreased heart rate of F-line embryos and has changed the weight of the heart relative to the total body weight until the embryo has passed through the plateau stage. The F-line embryos had a different energy metabolism that relies much more on gluconeogenesis. Embryo deaths occur more frequently in turkey embryos when the energy metabolism of the myocardium shows elevated glycogen to lactate ratios as it did in the pure E and F lines. PARTICIPANTS: In addition to the PI and supporting staff, Dr. Karl Nestor, OSU Professor Emeritus, has been a key collaborator in the work on the genetics of the turkey. Additionally, some of the research was done in cooperation with scientists at North Carolina State University, University of Arkansas and Michigan State University. TARGET AUDIENCES: This research will benefit commerical poultry producers by further defining mechanisms regulating the growth of poultry and, as a result, aid in increasing the efficiency of lean meat production. PROJECT MODIFICATIONS: Not relevant to this project.
Impacts
Recent studies have shown that the major gains in performance by the turkey industry were due to genetic improvement. An improvement of 0.5 percent in genetics of commercial turkeys would have a farm value of over 161 million dollars in the United States.
Publications
- Velleman, S. G., Coy, C. S., and Nestor, K. E. 2010. The influence of age on maternal inheritance of breast muscle morphology in turkeys. Poult. Sci. 89:876-882.
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Progress 01/01/09 to 12/31/09
Outputs
OUTPUTS: In cooperation with scientists at the University of Arkansas, three genetic lines were compared for their response to an Escherichia coli air sac challenge followed by transport stress (Transport). The turkey lines were a slow growing experimental line (E) selected long-term for increased egg production, a fast growing experimental line (F) selected long-term for increased 16-week body weight, and a commercial line (C). Birds from both sexes of each line were challenged at 14 weeks of age with an air sac injection of 5,000 to 10,000 cfu of E. Coli and were subjected to a transport stress procedure 8 days after the challenge that included a total of 12 hour holding time in a transport vehicle. At the end of Transport birds returned to their pens and provided with feed and water. The following morning all birds (number = 10 to 19 birds per line) were bled. This bleeding time was 1 day after Transport and 9 days after challenge with E. Coli. Whole blood was analyzed using the Cell-Dyn 3500 blood analysis system (Abbott Diagnostics) and serum chemistry was measured using the Express Plus analyzer (Cibia-Corning Diagnostic Corporation). Transport decreased hematocrit, hemoglobin, mean cell volume, mean corpuscular hemoglobin, glucose, triglycerides, cholesterol, phosphorus, iron, albumin, and alkaline phosphatase levels and increased uric acid, blood urea nitrogen, alanine aminotrasferase, aspartate aminotransferase, and creatine kinase. Line differences were variable but the levels of both iron and alkaline phosphatase were indirectly correlated with growth rate. Iron and alkaline phosphatase were the only parameters influence by sex of bird with males having higher levels of both compared to females. Creatine kinase levels were over 6-fold higher in transported C line birds and iron levels of transported C males were 3-fold lower than controls. Previously, the growth rate of these lines was positively correlated with increased heterophil to lymphocyte ratios and susceptibility to colibacillosis. The highly significant differences seen in the C line for these commonly measured blood parameters suggest that they may be useful for profiling flocks to determine their response to transport stress and feed withdrawal. PARTICIPANTS: Karl Nestor has been a key collaborator in the work on the genetics of the turkey. Some of the research was done in cooperation with scientists at North Carolina State University and University of Arkansas. TARGET AUDIENCES: This research will benefit commerical poultry producers by further defining mechanisms regulating the growth of poultry and aid in increasing the efficiency of lean meat production. PROJECT MODIFICATIONS: Not relevant to this project.
Impacts
Recent studies have shown that the major gains in performance by the turkey industry were due to genetic improvement. An improvement of 0.5 percent in the genetics of commercial turkeys would have a farm value of over 161 million dollars in the United States.
Publications
- Huff, G. R., Huff, W. E., Rath, N. C., Anthony, N. B., and Nestor, K. E. 2008. Effects of Escherichia coli challenge and transport stress on hematology and serum chemistry values of three genetic lines of turkeys. Poult. Sci. 87:2234-2241.
- Huff, G. R., Huff, W. E., Rath, N. C., Anthony, N. B., and Nestor, K. E. 2008. Effects of genetics, transport stress, and Escherichia coli challenge on hematology and clinical chemistry parameters of turkeys. Poult. Sci. 87 (Suppl. 1):14.
- Huff, G. R., Huff, W. E., Rath, N. C., Anthony, N. B., and Nestor, K. E. 2009. Differential effect of ascorbic acid supplementation on the stress response of turkeys from genetic lines differing in growth rate. Poult. Sci. 88 (Suppl. 1):84-85.
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Progress 01/01/08 to 12/31/08
Outputs
OUTPUTS: Turkey experimental lines E (selected 44 generations for increased total egg production for various periods of measurement) and F (selected 38 generations for increased 16-week body weight) were mated reciprocally with the randombred control lines from which they were derived (RBC1 and RBC2, respectively), and the pure line and reciprocally cross poults were compared for their body weight, heart weight, heart rates, myocardial glycogen and lactate concentrations, and plasma creatine kinase and lactate dehydrogenase activities. Activities of the latter two enzymes are indicative of myocardial damage and insufficiency. Orthogonal contrasts of the data from the pure lines and reiciprocal crosses were used to estimate additive genetic effects, reciprocal effects (confounded maternal and sex-linked effects), and heterosis for each of the traits measured. Additive genetic effects were evident for relative heart rate in the embryo at internal and external pipping and in poults at hatch. Additive genetic effects were also observed for heart rate, cardiac muscle glycogen, cardiac muscle glycogen to lactate ratios, hepatic glycogen concentrations, hepatic lactate concentrations, and hepatic glycogen to lactate ratios. Significant heterosis was observed for fertility (4.2 to 6.3 percent), death at external pipping (-46.1 percent), heart rates (-4.6 percent), cardiac muscle glycogen (-18.5 percent), cardiac muscle lactate (-13.5 percent), hepatic glycogen concentration (-25.0 percent), plasma creatine kinase activity (13.1 percent), plasma lactate dehydrogenase activity (-16.4 percent), and plasma glucose concentration (4.8 percent). Long-term selection for increased egg production in the E line reduced embryo heart weight and has altered the energy metabolism of the myocardium. The difference in energy metabolism may be due to the more rapid heart rates of the E line relative to the RBC1 line. Conversely, long-term selection for increased 16-week body weight in the F line significantly decreased the heart rate of the embryo and has not changed the weight of the heart relative to body weight until the embryo has passed through the plateau stage of incubation. Embryo deaths occur more frequently in turkey embryos when the energy metabolism of the myocardium shows elevated glycogen to lactate ratios as it did in the pure E and F lines relative to the corresponding randombred controls. PARTICIPANTS: Karl Nestor has been a key collaborator in the work on the genetics of the turkey. Some of the research was done in collaboration with the Department of Poultry Science at North Carolina State University. TARGET AUDIENCES: Not relevant to this project. PROJECT MODIFICATIONS: Not relevant to this project.
Impacts
Recent studies have shown that the major gains in performance by the turkey industry were due to genetic improvement. An improvement of 0.5 percent in the genetics of commercial turkeys would have a farm value of over 161 million dollars in the United States.
Publications
- Christensen, V. L., Ort, D. T., Nestor, K. E., Havenstein, G. B., and Velleman, S. G. 2008. Genetic control of embryonic cardiac growth and functional maturation in turleys. Poult. Sci. 87:858-873.
- Nestor, K. E., Anderson, J. W., Patterson, R. A., and Velleman, S. G. 2008. Genetics of growth and reproduction in the turkey. 17. Changes in genetic parameters over forty generations of selection for increased sixteen-week body weight. Poult. Sci. 87:1971-1979. Peebles, E. D., Willeford, K. O., Keirs, K. W., Nestor, K. E., Saif, Y. M., Wang, C., Matyi, C. J., Anderson, J. W., Kidd, M. T, and Palikanti, R. 2008. Use of a caprine serum faction-immunomodulator to reduce mortality in commercial and large-bodied turkey lines infected with Pasteurella multocida. Int. J. Pout. Sci. 7:818-824.
- Zhang, X., Nestor, K. E.., McFarland, D. C., and Velleman, S. G. 2008. The role of syndecan-4 and attached glycoasaminoglycan chains on myogenic satellite cell growth. Matrix Biol. 27:619-630.
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Progress 01/01/07 to 12/31/07
Outputs
OUTPUTS: Forty generations of selection has been completed in the line (F) of turkeys selected long-term for increased 16-wk body weight and the base population (RBC2) has been maintained along with the F line as a random bred control. The RBC2 line has been maintained without conscious selection and used to remove yearly environmental variation in the F line. Selection has been effective in increasing 16-wk body weight in the F line. Selection differentials based on the mean of the selected parents minus the mean of the entire population (intended) and intended selection differential weighted for the number of offspring produced (actual) did not differ consistently, indicating that natural selection was not opposing artificial selection during the reproduction of the F line. The realized heritability of 16-wk body weight, based on the linear regression of the selection response on accumulated actual selection differential declined with selection. For both sexes combined, the
realized heritability was 0.309, 0.268, 0.242, 0.166, and 0.242, respectively, for generations 1 to 10, 11 to 20, 21 to 30, 31 to 40, and 1 to 40. Genetic increases in 16-wk body weight in the F line over 40 generations of selection were positively associated with body weight at other ages (8 and 20 wk of age and at 50% production), shank width and length at 16 wk of age, days from stimulatory lighting to production of the first egg, and egg weight, but were negatively associated with egg production, intensity of lay (maximum and average clutch length and rate of lay) and walking ability. Clutch length is defined as the number of consecutive days that an egg is laid before skipping a day or days. Over the 40 generations of selection, genetic increases in body weight in the F line were not associated with changes in broodiness or mortality to 8 wk of age. Broodiness is the desire of a hen to incubate eggs and usually results in a reduction in egg production. Broodiness was measured by
total days lost in periods of five or more consecutive days of non-production. During generations 31 to 40, body weight at 8 and 20 wk of age continued to increase in the F line relative to the RBC2 line but there was no significant change in adult body weight of the females and the only significant change in reproduction traits was a linear reduction in average clutch length. Because the genetic changes in some correlated traits (egg production, days from stimulatory lighting to production of first egg, walking ability, and egg weight) were not consistent in all generation intervals studied (1 to 10, 11 to 20, 21 to 30, and 31 to 40), the realized genetic correlation between the selected trait (16-wk body weight) and the correlated trait apparently changed with selection.
PARTICIPANTS: Karl Nestor, Professor Emeritus, The Ohio State University has been a key collaborator in the work on the genetics of the turkey. Some of the research was done in collaboration with North Carolina State University, Dept. of Poultry Science.
Impacts
Recent studies have shown that the major gains in performance by the turkey industry was due to genetic improvement. An improvement of 0.5 percent in the genetics of the commercial turkey would have a farm value of over 161 million dollars in the United States.
Publications
- Christensen, V.L., Ort, D.T., Nestor, K.E., Velleman, S.G., and Havenstein, G.B. 2007. Genetic control of neonatal growth and intestinal matruation in turkeys. Poult. Sci. 86:476-487.
- Havenstein, G.B., Ferket, P.R., Grimes, J.L., Qureshi, M.A., and Nestor, K.E. 2007. Comparison of the performance of 1966- versus 2003-type turkeys when fed representative 1996 and 2003 turkey diets: Growth rate, livability, and feed conversion. Poult. Sci. 86:232-240.
- Cheema, M.A., Qureshi, M.A., Havenstein, G.B., Ferket, P.R., and Nestor, K.E. 2007. A comparison of the immune response of 2003 commercial turkeys and a 1966 randombred strain when fed representative 2003 and 1966 diets. Poult. Sci. 86:241-248.
- Christensen, V.L., Havenstein, G.B., Ort, D.T., McMurtry, J.P. and Nestor, K.E. 2007. Dam line and sire line effects on turkey embryo survival and thyroid hormone concentrations at the palteau stage in oxygen consumption. Poult. Sci. 86:1861-1872.
- Zhang, X., Liu, C., Nestor, K.E., McFarland, D.C., and Velleman, S.G. 2007. The effect of glypican-1 glycosaminoglycan chains on turkey myogenic satellite cell proliferation, differentiation, and fibroblast growth factor 2 responsiveness. Poult. Sci. 86:2020-2028.
- Velleman, S.G., Coy, C.S., Anderson, J.W., and Nestor, K.E. 2007. The effect of genetic increases in egg production and age and sex on breast muscle development in turkeys. Poult. Sci. 86:2134-2138.
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Progress 01/01/06 to 12/31/06
Outputs
The major world turkey breeders normally cross a sire line (or sire line cross) to a dam line (or dam line cross) to produce commercial turkeys. The sire lines are normally selected primarily for growth-related traits while the major emphasis in dam lines is on egg production with some selection pressure applied to growth traits. The turkey industry's view of the relative economic importance of growth and egg production has changed rapidly. Genetic changes by selection within lines may not be rapid enough to meet the changing needs. The feasibility of rapidly increasing the body weight of dam lines by repeated backcrosses of a dam line to a sire line was tested. An experimental line (E) was selected, long-term, for increased egg production and was used as a model for a commercial dam line. A commercial sire line (B) from a major turkey breeder was used in the study. The B line was larger (more than 3-fold) in body weight at 8, 16, and 20 weeks of age, had wider
breasts (approximately 1.8-fold) at 16 weeks of age, and had lower egg production for 180d (about 3-fold) than the E line. Based on the assumption of additive genetic variation, males in the F1 generation of the B x E cross did not differ from expected in body weight at any age, but females of this cross had body weight less than expected at 16 and 20 weeks of age. In the F1 generation, breast width of the cross did not differ from the expected value, but egg production for 180d was greater than expected (126.6 versus 102.3 eggs/hen). After three generations of backcrossing, the backcrosses exhibited a gain in 20-week body weight of 12.5 and 8.8 kg, respectively, for males and females; a gain of 5.9 and 5.3 cm in breast width at 16 weeks of age for males and females, respectively; and a loss of 74.1 eggs per hen over a 180d egg production period. Based on the results of the current and a previous study, limited backcrossing of a dam line to a sire line may be an economically feasible
method to greatly increase the body weight of dam lines without unduly sacrificing egg production. For maxima gains per generation, backcrossing probably should be used for a maximum of two or three generations.
Impacts
The turkey industry raised an estimated 266.5 million turkeys in 2006. The average consumption of turkey meat was 16.7 pounds per person. The farm income for turkey production in the United States was 3.23 billion dollars in 2005. The United States turkey industry exported 388.6 million dollars worth of turkey meat in 2005. The growth rate of turkeys is largely controlled by their genetics. Gains in growth rate by genetic selection or manipulation the mating system by commercial turkey breeders can have a major economic impact on the turkey industry. An improvement of 0.5 percent in the genetics of the commercial turkey would have a farm value of 161.5 million dollars based on 2005 values.
Publications
- Huff, G., Huff, W., Rath, N., Balog, J., Anthony, N.B., and Nestor, K.E. 2006. Stress induced colibacillosis and turkey osteomyelitis complex in turkeys selected for increased body weight. Poult. Sci. 85:266-272.
- Liu, C., McFarland, D.C., Nestor, K.E., and Velleman, S.G. 2006. Differentiatial expression of membrane-associated heparan sulfate proteoglycans in skeletal muscle of turkeys with different growth rates. Poult. Sci. 85:422-428.
- Nesotr, K.E., Anderson, J.W., Patterson, R.A., and Velleman, S.G. 2006. Genetics of growth and reproduction in the turkey. 16. Effect of repeated backcrossing of an egg line to a commercial sire line. Poult. Sci. 85:1550-1554.
- Velleman, S.G., Nestor, K.E. 2006. Inheritance of breast muscle morphology in a line of turkeys selected long term for increased egg production, its randombred control line, and reciprocal crosses among them. Poult. Sci. 85:2130-2134.
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Progress 01/01/05 to 12/31/05
Outputs
An experimental line (F) selected over 34 generations for increased 16-wk body weight was reciprocally crossed with a primary breeding sire line (C) from a large international turkey breeder to study the inheritance of growth-related traits measured on live birds. All genetic groups were grown intermingled in confinement with sexes reared in different houses. The traits measured included body weight at 8, 16, and 20 wk of age and shank length, shank width, shank depth, breast width, and walking ability scores at 16 wk of age. Walking ability was rated from 1 to 5 with 1 representing birds with no leg defects and no difficulty walking and 5 indicating birds with extreme lateral deviations of the legs and great difficulty walking. Ratings of 2, 3, and 4 represented intermediate values. The F line had a different growth pattern than the C line with the F line being larger than the C line at 8 weeks of age, but the reverse was true at 16 and 20 weeks of age. The
difference in body weight between the C and F lines increased from 16 to 20 weeks of age. The C line had wider breasts than the F line at 16 weeks of age. The F line had longer shanks than the C line. Shank width was larger in the C line than the F line for females but not males. No line difference in shank depth was observed. Walking ability scores at 16 weeks of age were lower (better) in the C line than in the F line for males but not females. Significant heterosis in body weight of the crosses of the F and C lines was observed at all ages in males (range = 3.3 to 5.6%) and only at 8 weeks of age in females (3.6%). These results were similar to an earlier study in which the F line was crossed with a primary-breeding sire line from 2 other international turkey breeders. No significant heterosis in the crosses of the C and F lines was observed for breast width and shank measurements. Heterosis was significant for walking ability scores of females (-3.0%) but not males. Reciprocal
effects, a measure of sex linkage and maternal influences, were noted only for shank length and the direction of the differences was not the same in the 2 sexes.
Impacts
Mating schemes in turkeys depend of the inheritance of the traits involved in the selection program. The larger amount of heterosis in males than in females for body weight indicates that additive genetic variation is still very important in the genetic improvement of growth rate in turkeys.
Publications
- Nestor, K. E., J. W. Anderson, D. Hartzler, and S. G. Velleman, 2005. Genetic variation in pure lines and crosses of large-bodied turkeys. 4. Body shape and carcass traits. Poultry Sci. 84:1825-1834.
- Huff, G. R., W. E. Huff, J. M. Balog, N. C. Rath, N. B. Anthony, and K. E. Nestor, 2005. Stress response differences and disease susceptibility reflected by heterophil to lymphocyte ratio in turkeys selected for increased body weight. Poultry Sci. 84:709-717.
- Nestor, K. E., J. W. Anderson, and S. G. Velleman, 2005. Genetic variation in pure lines and crosses of large-bodied turkey lines. 3. Growth related measurements on live birds. Poultry Sci. 84:1341-1346.
- Velleman, S. G., and K. E. Nestor, 2005. Effect of genetic increases in egg production, age, and sex on muscle development of turkeys. Poultry Sci. 84:1347-1349.
- Huff, G. R., W. E. Huff, N. C. Rath, J. M. Balog, N. B. Anthony, and K. E. Nestor, 2005. Colibacillosis and turkey osteomyelitis complex in turkeys selected for increased body weight and subjected to stress. Poultry Sci. 84 (Suppl. 1):17.
- Christensen, V. L., B. D. Fairchild, D. T. Ort, and K. E. Nestor, 2005. Dam and sire effects on sperm penetration of the perivitelline layer and resulting fecundity of different lines of turkeys. J. Appl. Poult. Sci. 14:483-491.
- Huff, G. R., W. E. Huff, J. M. Balog, N. C. Rath, N. B. Anthony, and K. E. Nestor, 2005. Hematological changes reflect stress response differences and disease susceptibility in lines of turkeys selected for increased body weight. Poultry Sci. 84 (Suppl. 1):105.
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Progress 01/01/04 to 12/31/04
Outputs
The turkey lines selected long term for increased egg production (E line) and increased 16-week body weight (F line) and their corresponding randombred controls (RBC1 and RBC2 lines, respectively) are being maintained. The E line is being maintained with selection for increased 250-day egg production using 72 parental pairs. The F line is being maintained by artificially mating 36 sires to 72 dams, with 1 sire being mated to 2 dams. The line (FL line) selected for increased shank width has been discontinued. Inheritance of breast muscle morphology is being studied in the turkey lines. Recent studies of the F and RBC2 lines and reciprocal crosses among them confirm that the morphology patterns observed at 16 weeks of age are maternally inherited. Selection for increased egg production in the E line did not influence breast muscle development. The Japanese quail lines are also being maintained. All lines were developed from a randombred control line (R1). Lines were
developed from the R1 line by divergently selecting long term for increased (HW line) or decreased (LW line) 4-week body weight. Additional sublines of the R1 line were developed by selecting long term for increased (HP line) or decreased (LP line) total plasma phosphorus (TPP) at the beginning of lay. The TPP is a measure of circulating plasma very low density lipoprotein. The R1, HP, and LP lines are being maintained with 36 parental pairs. The HW and LW lines are being maintained with 48 parental pairs. Selection is being applied in the HW and HP lines but the LW and LP lines are being randombred without selection because these lines were reaching a biological limit. Genetic gains in the LW line had ceased because natural selection was strongly opposing artificial selection as mortality shortly after hatching had greatly increased in recent generations of the LW line. In the LP line, the TPP had been reduced to a level such that further reductions would have resulted in a cessation
of egg production so selection had reached a plateau. Two sublines (HW-HP and HW-LP) of the HW line have been discontinued.
Impacts
Knowledge on genetic variation of egg production and growth traits is important for commercial breeders in maintaining their selection lines. The finding of maternal inheritance of breast muscle morphology will greatly influence the manner of crossing commercial sire and dam lines for the production of commercial offspring.
Publications
- Liu, X., D. C. McFarland, K. E. Nestor, and S. G. Velleman, 2004. Developmental regulated expression of syndecan-1 and glypican in pectoralis major muscle in turkeys with different growth rates. Dev. Growth Differ. 46:37-51.
- Nestor, K. E., J. W. Anderson, R. A. Patterson, and S. G. Velleman, 2004. Genetic variation in body weight and egg production in an experimental line selected long term for increased egg production, a commercial dam line, and reciprocal crosses between lines. Poultry Sci. 83:1055-1059.
- Velleman, S. G., and K. E. Nestor, 2004. Inheritance of breast muscle morphology in turkeys at sixteen weeks of age. Poultry Sci. 83:1060-1066.
- Liu, X., K. E. Nestor, and S. G. Velleman, 2004. The influence of selection for increased body weight and sex on pectoralis major muscle weight during the embryonic and posthatch periods. Poultry Sci. 83:1089-1092.
- Havenstein, G. B., P. R. Ferket, J. L. Grimes, M. A. Qureshi, and K. E. Nestor, 2004. Performance of 1966 vs. 2003 turkeys when fed representative 1966 and 2003 turkey diets. Proc. Worlds Poultry Congress, Istanbul, Turkey.
- El-Karedy, K. Nestor, and M. Lilburn, 2004. Effect of dietary Protein, and genetic background on growth and sexual maturity in Japanese quail. Poultry Sci. 80 (Suppl. 1):44.
- Reddish, J. M., A. El-Keredy, K. E. Nestor, and M.S.Lilburn, 2004. Relationships between skeletal growth and body weight in Japanese quail selected for 4 week body weight. Poultry Sci. 80 (Suppl. 1):42.
- Block, M. L., K. E. Nestor, and G. F. Barbato, 2004. Zona pellucida 3 protein (ZP3) and gene (ZPC) expression in the turkey, Meleagris gallopavo. Poultry Sci. 80 (Suppl. 1):344.
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Progress 01/01/03 to 12/31/03
Outputs
A line (E) of turkeys selected long-term (40 generations) for increased egg production was reciprocally crossed with a commercial dam line (B) to study the inheritance of growth and egg production traits. The B line was more than twice as large as the E line and had better conformation. than the E line. However, the E line laid more eggs (147 per hen) than the B line (114 per hen) over a 180-day production period. Heterosis was negative and significant for body weight at 8, 16, and 20 weeks of age (both sexes; range 3.4 to 5.5%) and at 50% egg production (females only; 3.1%) and for breast width at 16 weeks of age (11 % for males and 3 % for females). Heterosis was positive and significant for egg production when recorded for 84 (9.2 %), 120 (10.2 %), and 180 (11.3 %) days. Heterosis (- 8 %) was significant for rate of response to stimulatory lighting of 14 hours per day (days from stimulatory lighting to production of first egg). Based on the data for a 180-day
production period, heterosis was observed in average clutch length (13 %) and rate of lay (number of eggs laid on nonbroody days; 8 %) but not in total days lost from broodiness or the effective length of the laying period (180 days minus days lost in periods of five or more consecutive days at the end of the laying period). The results of the current study and published experiments indicate that heterosis for egg production is an important source of variation in crosses of lines differing greatly in body conformation. Reciprocal effects in the crosses of the B and E lines indicating sex linkage or maternal effects were not significant for egg production traits but were consistently significant for body weight during the growing period and at 50 % production. There was a large difference in egg weight between the parental lines and this may have contributed to the reciprocal effects observed. Possible maternal inheritance of breast muscle morphology at 16 weeks of age was observed in
reciprocal crosses of a line (F) selected long-term (35 generations) for increased 16-week body weight and its randombred control (RBC2) and in reciprocal crosses of the F line and the B line. The B, F, and RBC2 lines had distinct morphology and the breast morphology of the reciprocal crosses was almost identical to that of the maternal parent. The maternal inheritance of breast morphology has been confirmed in F2 crosses.
Impacts
Knowledge on genetic variation of egg production and growth traits is important for commercial breeders in maintaining their selection lines. The finding of maternal inheritance of breast muscle morphology will greatly influence the manner of crossing commercial sire and dam lines for the production of commercial offspring.
Publications
- Ding, S. T., Y. C. Li, K. E. Nestor, S. G. Velleman, and H. J. Mersmann, 2003. Expression of turkey transcription factors and acyl-coenzyme oxidase in different tissues and genetic populations. Poultry Sci. 82:17-24.
- Reddish, J. M., K. E. Nestor, and M. S. Lilburn, 2003. Effect of selection for growth on onset of sexual maturity in randombred and growth-selected lines of Japanese quail. Poultry Sci. 82:187-191.
- Velleman, S. G., J. W. Anderson, C.S. Coy, and K. E. Nestor, 2003. Effect of selection for growth rate on muscle damage during turkey breast muscle development. Poultry Sci. 82:1069-1074.
- Velleman, S. G., and K. E. Nestor, 2003. Effect of selection for growth rate on myosin heavy chain temporal and spatial localization during turkey breast muscle development. Poultry Sci. 82:1373-1377.
- Velleman, S. G., J. W. Anderson, and K. E. Nestor, 2003. Possible maternal inheritance of breast muscle morphology in turkeys at sixteen weeks of age. Poultry Sci. 82:1479-1484.
- Liu, X., D. C. McFarland, K. E. Nestor, and S. G. Velleman, 2003. Expression of fibroblast growth factor 2 and its receptor during muscle development from turkeys with different growth rates. Dom. Anim. Endocrinol. 25:215-229.
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Progress 01/01/02 to 12/31/02
Outputs
A line (E) of turkeys selected long-term (37 generations) for increased egg production was reciprocally crossed with its randombred control population (RBC1) that served as the base population of the E line to study the influence of long-term selection on the development of nonadditive genetic variation for egg production and body weight traits. Heterosis was significant for body weight at 8, 16, and 20 weeks of age and at 50% egg production (females only). At 16 and 20 weeks of age, heterosis was significant only for male offspring. No heterosis was observed in the reciprocal crosses for egg production when measured for 84, 180, or 250 days. Heterosis was significant for rate of response to stimulatory lighting of 14 hours per day (days from stimulatory lighting to production of first egg). Based on the data for a 250-day production period, heterosis was observed in average clutch length but not in total days lost from broodiness or the effective length of the laying
period (250 days minus days lost in periods of five or more consecutive days at the end of the laying period). The results suggest that long-term selection for increased egg production and the correlated decrease in body weight increased the relative nonadditive genetic variation in body weight. Reciprocal effects were significant for body weight at 8 and 16 weeks of age, probably due to a large difference in egg weight between the E and RBC1 lines. In a study of developmental stability (DS) of several Japanese quail lines, the following results were obtained: 1) homozygosity did not influence DS; 2) DS tended to be higher in lines selected for decreased total plasma phosphorus; 3) selection for increased or decreased 4-week body weight did not influence DS; and 4) bilateral asymmetry was not a good measure of DS in the Japanese quail lines.
Impacts
Knowledge of the effect of long-term selection on genetic variation within the lines and stability of the lines is useful for commercial breeders in maintaining their selection lines.
Publications
- Nestor, K. E., W. L. Bacon, S. G. Velleman, J. W. Anderson, and R. A. Patterson, 2002. Effect of selection for increased body weight and increased plasma yolk precursor on developmental stability in Japanese quail. Poultry Sci. 81:160-168.
- Emmerson, D. A., S. G. Velleman, and K. E. Nestor, 2002. Genetics of growth and reproduction in the turkey. 15. Effect of long-term selection for increased egg production on the genetics of growth and egg production traits. Poultry Sci. 81:316-320.
- Christensen, V. L., G. S. Davis, and K. E. Nestor, 2002. Environmental incubation factors influence embryonic thyroid hormones. Poultry Sci. 81:442-450.
- Velleman, S. G., C. S. Coy, J. W. Anderson, R. A. Patterson, and K. E. Nestor, 2002. Effect of selection for growth rate on embryonic breast muscle development in turkeys. Poultry Sci. 81:1113-1121.
- Saif, Y. M., and K. E. Nestor, 2002. Increased mortality in turkeys selected for increase body weight following vaccination with a live Newcastle disease virus vaccine. Avian Dis. 46:505-598.
- Liu, X., K. E. Nestor, D. C. McFarland, and S. G. Velleman, 2002. Developmental expression of skeletal muscle heparan sulfate proteoglycans in turkeys with different growth rates. Poultry Sci. 81:1621-1628.
- Sacco, R. E., R. B. Rimler, X. Ye, and K. E. Nestor, 2001. Identification of new major histocompatibility complex Class II restriction fragment length polymorphisms in a closed experimental line of Beltsville Small White turkeys. Poultry Sci. 80:1109-1111.
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Progress 01/01/01 to 12/31/01
Outputs
An experimental line (F) of turkeys was reciprocally crossed with sire lines (designated A and B) from each of two commercial breeders in order to study the inheritance of carcass traits and body shape. The birds were weighed and killed at 17 wk of age and various measurements of muscling, leg bones, and body shape were made. Additive genetic variation, as indicated by line differences, was an important source of variation in most traits. The only traits that did not exhibit a line difference in any comparison were weight of the drumstick muscles, tarsometatarsal width, keel length, and Body Depth 2 (body depth at a point 2.54 cm anterior to the posterior end of the keel). Heterosis of live BW was greater in males than in females. Heterosis in the weight of the Pectoralis major and P. minor muscles was similar to that of live BW but heterois in the weight of the leg muscles was higher than that of live BW. The average heterosis for bone measurements (length of the
femur, tarsometatarsal, and tibiotarsal bones and tarsometatarsal width) was very low and ranged from - 0.3 to 1.4 %. For measurements of body shape [keel length, Body Depth 1 (body depth measured at the cranial process of the keel), Body Depth 2, ratio of Body Depth 1 to Body Depth 2, length, width, and height of the body cavity, and body cavity volume index), heterosis was low and the average ranged from - 2.7 to 2.6 %. Based on an analysis of both sexes combined, the commercial sire lines differed in BW, weights of the P. minor and drumstick muscles, weights of the tarsometatarsal, femur, and tibiotarsal bones, lengths of the tarsometatarsal and femur bones, and various measurements of body shape (Body Depth 1, body depth ratio, body cavity length and height, and body cavity volume index). Relative to the commercial sire lines, the F line was smaller, had less breast and leg muscling, and, in general, larger leg bones when sexes were combined. The carcass of the F line was deeper
than that of the commercial sire lines when measured at the cranial process of the keel but not at 2.54 cm anterior to the posterior portion of the keel. Body cavity height and body cavity volume index were larger in the F line than in the commercial sire lines.
Impacts
Knowledge of the genetics of body shape in crosses of large-bodied turkeys lines should assist turkey breeders in their selection program.
Publications
- Soboyejo, A. B. O., and K. E. Nestor, 2000. A new statistical biomechanics approach to modeling bone strength in turkeys and broiler chickens. Trans. Am. Soc. Agric. Enj. 43:1997-2006.
- Li, Z., K. E. Nestor, Y. M. Saif, J. W. Anderson, and R. A. Patterson, 2001. Effect of selection for increased body weight in turkeys on lymphoid organ weights, phagocytosis, and antibody responses to fowl cholera and Newcastle disease-inactivated vaccines. Poultry Sci. 80:689-694.
- Nestor, K. E., J. W. Anderson, and S. G. Velleman, 2001. Genetic variation in pure lines and crosses of large-bodied turkey. lines. 1. Body weight, walking ability, and body measurements of live birds. Poultry Sci. 80:1087-1092.
- Nestor, K. E., J. W. Anderson, and S. G. Velleman, 2001. Genetic variation in pure lines and crosses of large-bodied turkey. lines. 2. Carcas traits and body shape. Poultry Sci. 80:1093-1104.
- Velleman, S. G., and K. E. Nestor, 2001. Mode of inheritance of the low score normal condition in chickens. Poultry Sci. 80:1273-1277.
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Progress 01/01/00 to 12/31/00
Outputs
Theoretically, the relative proportion of additive genetic variation declines and the proportion of non-additive genetic variation increases with long-term selection. Non-additive genetic variation is responsible for heterosis in crosses of lines. A line (E) of turkeys selected long term (37 generations) for increased egg production was reciprocally crossed with its randombred control population (RBC1) that served as the base population of the E line to study the influence of long-term selection on the development of nonadditive genetic variation in egg production and body weight traits. Previous measurements or realized heritabilites in the E line suggested that the additive genetic variation for egg production may be declining in the E line. However, no heterosis in the reciprocal crosses was observed for egg production when measured for 84, 180, or 150 days. Heterosis was significant for rate of response to stimulatory lighting of 14 hours per day (days from
stimulatory lighting to the production of the first egg). Based on data for a 250-day production period, heterosis was observed in average clutch length but not in total days lost from broodiness or the effective length of the laying period (250 minus days lost in periods of 5 or more consecutive days at the end of the laying period). Heterosis was significant for body weight at 8, 16, and 20 weeks of age and at 50% egg production (females only). At 16 and 20 weeks of age, heterosis in body weight was significant only for male offspring. The present results suggest that long-term selection for increased egg production and the resulting correlated
Impacts
Knowledge of the changes in genetic parameters in long-term selection studies is useful to commercial breeders and contributes to the base of general information concerning the effects of selection on these parameters.
Publications
- Ye, X., H. L. Marks, K. E. Nestor, W. L. Bacon, and S. G. Velleman, 1999. Genetic relationship among lines and smooth muscle and ovarian follicular development within lines of Japanese quail in two long-term selection studies. Poultry Sci. 78:1372-1376.
- Li, Z., K. E. Nestor, Y. M. Saif, J. W. Anderson, and R. A. Patterson, 2000. Serum immunoglobulin D and M concentrations did not appear to be associated with resistance to Pasteurella multocida in a large-bodied turkey line and a randombred control population. Poultry Sci. 79:163-166.
- Li, Z., K. E. Nestor, Y. M. Saif, and M. Luhtala, 2000. Flow cytometric analysis of T lymphocyte subpopulations in large-bodied turkey lines and a randombred control population. Poultry Sci. 79:219-223.
- Nestor, K. E., J. W. Anderson, and R. A. Patterson, 2000. Genetics of growth and reproduction in the turkey. 14. Changes in genetic parameters over thirty generations of selection for increased body weight. Poultry Sci. 79:445-452.
- Li, Z., K. E. Nestor, Y. M. Saif, and J. W. Anderson, 2000. Antibody responses to sheep red blood cell and Brucella abortus antigens in a turkey line selected for increased body weight and its randombred control. Poultry Sci. 79:804-809.
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Progress 01/01/99 to 12/31/99
Outputs
A turkey line (F) selected long-term for increased 16-week body weight is more susceptible to a number of disease organisms (Erysipelothrix rhusiopathiae, Pasteurella multocida, Newcastle disease virus, and Bordetella avium) than its randombred control line (RBC2) which served as the base population of F. Mortality following challenge with P. multocida was similar in the F line and two commercial sire lines. A third commercial sire line had less mortality than the F line following challenge but both large-bodied lines had more mortality than the RBC2 line. Changes in the immune system of the F line relative to the RBC2 line included: 1) a decrease in phagocytic activity as measured by the carbon clearance assay; 2) an increase in IgM concentration in the blood at 6 wk of age; 3) a decrease in mitogenic response of peripheral blood mononuclear cells (PBMC) to concanavalin A; 4) higher antibody response to sheep red blood cells (thymus-dependent antigen); 5) higher
frequency of CD8 alpha polymorphism; 6) an increase in the CD4+CD8- cell subset; and 7) an increase in the CD4:CD8 ratio. No differences between the F and RBC2 lines were observed for: 1) IgG concentration in the blood at 6 wk of age; 2) mitogenic response of PBMC to phytohemagglutinin M; and 3) antibody responses to Newcastle disease virus, P. multocida, or Brucella abortus (thymus-independent) antigens. There was no relationship between concentration of IgG or IgM in the blood prior to challenge with P. multocida and days to death following challenge.
Impacts
Knowledge of the changes in the immune system due to genetic increases in body weight should assist commercial breeders in devising methods to improve genetic resistance to diseases along with growth rate.
Publications
- Noble, D.O., K.E. Nestor and C.R. Polly. 1999. Factors influencing early poult flip-overs in experimental populations of turkeys. Poultry Sci. 78:178-181.
- Nestor, K.E., M.S. Lilburn, Y.M. Saif, J.W. Anderson, R.A. Patterson, Z. Li and J.E. Nixon. 1999. Influence of body weight restriction in a body-weight-selected line of turkeys on response to challenge with Pasteurella multocida. Poultry Sci. 78:1263-1267.
- Anthony, N.B., K.E. Nestor, D.A. Emmerson, Y.M. Saif, R. Vasilatos-Younken and W.L. Bacon. 1999. Effect of feed withdrawal or challenge with Pasteurella multocida on growth, blood metabolites, circulating growth hormone, and insulin-like growth factor-I concentrations in eight-week old turkeys. Poultry Sci. 78:1268-1274.
- Nestor, K.E., Y.M. Saif, J.W. Anderson, R.A. Patterson and Z. Li. 1999. Variation in resistance to Pasteurella multocida among turkey lines. Poultry Sci. 78:1377-1379.
- Li, Z., K.E. Nestor, Y.M. Saif, W.L. Bacon and J.W. Anderson. 1999. Effect of selection for increased body weight on mitogenic responses in turkeys. Poultry Sci. 78:1532-1535.
- Li, Z., K.E. Nestor, Y.M. Saif, Z. Fan, M. Luhtala and O. Vainio. 1999. Cross-reactive anti-chicken CD4 and CD8 monoclonal antibodies suggest polymorphism of the turkey CD8 alpha molecule. Poultry Sci. 78:1526-1531.
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Progress 01/01/98 to 12/31/98
Outputs
Response to selection in the line (F) of turkeys selected long-term for increased 16-wk. body weight was analyzed in 10 generation intervals (1-10, 11-20, and 21-30) and overall to estimate changes in genetic parameters with selection. Selection was effective in increasing 16-wk. body weight in the F line. Intended and actual selection differentials did not consistently differ indicating that natural selection was not opposing the artificial selection. The realized heritability of 16-wk. body weight declined with selection and the decline appeared to be slightly different for males than females. For both sexes combined, the realized heritability was .31, .27, .24, and .25, respectively, for Generations 1-10, 11-20, 21-30, and 1-30. Genetic increases in 16-wk. body weight in the F line were positively associated with body weight at other ages (8, 20, and 24 wks. of age and at 50% production), days from stimulatory lighting to production of the first egg, and egg weight
and negatively associated with egg production, intensity of lay (as measured by maximum and average clutch length and rate of lay), and hatch of fertile eggs. There was no significant relationship of 16-wk. body weight and total days lost from broodiness and fertility. The genetic changes in some correlated traits were not consistent in all generation intervals studied indicating that the genetic correlation between the selected trait (16-wk. body weight) and the correlated trait changed with selection. Changes in egg production and intensity of lay in the F line were larger in Generations 1 to 10 than later in selection. Days from stimulatory lighting to production of the first egg and egg weight changed only during Generations 1 to 10. Hatch of fertile eggs changed only during Generations 11 to 20. The F line has a different growth pattern than the sire lines from the three major commercial turkey breeders in the world. In comparison with one of these commercial sire lines, the F
line had heavier body weights at 8 and 16 wks. of age but was smaller at 20 wks. of age. The F line and another commercial sire line had similar body weights at 8 wks. of age but the F line was smaller at 16 and 20 wks. of age. For the third commercial sire line, the F line was larger at 8 wks. of age but smaller at older ages. These data also indicated that the commercial sire lines differed in growth patterns.
Impacts
(N/A)
Publications
- Ely, D., K. E. Nestor, W. L. Bacon, R. A. Patterson, D. Smith, J. W. Anderson, and D. O. Noble, 1998. The effect of divergent selection for total plasma phosphorus in Japanese quail on fearfulness and selected blood and heart parameters. Poultry Sci. 77:8-16.
- Nestor, K. E., and J. W. Anderson, 1998. Effect of crossing a line selected for increased shank width with two commercial sire lines on performance and walking ability of turkeys. Poultry Sci. 77:1601-1607.
- Stephens, J. F., and F. V. Muir, 1998. College seniors' views on use of animals. Poultry Sci. 77(Suppl. 1):98.
- Christensen, V. L., W. E. Donaldson, and K. E. Nestor, 1998. Relation of eggshell conductance constants and genetics to survival of turkey embryos. Poultry Sci. 77(Suppl. 1):78.
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Progress 01/01/97 to 12/31/97
Outputs
Developmental patterns in turkeys of tissue ornithine decarboxylase (ODC) activity and nucleic acid concentrations were studied in a randombred control (RBC2), in a subline (F) of RBC2 selected for increased 16-wk body weight (BW), and in a commercial sire line (C). Lines F and C were similar in BW but C had greater breast weights. Lines F and C were heavier and had greater breast weights than RBC2. Tissue ODC activity reached its highest level on Day 2 posthatch, declined rapidly through 13 d of age, and remained relatively low through 144 d of age. The ODC activity of liver tissue was greater than that of breast or leg muscle. Line C had greater tissue ODC activity at 2 and 8 d of age than RBC2 but F was not different from C or RBC2. There were no line differences for ODC activity at the other ages tested. The DNA content of muscle tissue was greatest at hatch and decline to baseline values by 55 d of age. The DNA content of breast muscle was higher than for leg
muscle at hatch but this pattern was reversed following Day 8. Muscle tissue from F and C had a lower DNA content than that of the RBC2 line. The RNA content was similar across lines. The results demonstrated that changes in muscle cellularity during the growth phase are associated with genetic increases in BW but not breast muscle development and ODC activity was increased in association with increases in breast muscle but not BW.
Impacts
(N/A)
Publications
- NOBLE,D.O.et al. 1996. The effect of beak trimming on two strains of commercial tom turkeys. 2. Behavior traits. Poult. Sci. 75:1468-1471.
- EMMERSON,D.A.et al. 1997. Nucleic acid concentration and ornithine decarboxylase activity in tissues from three lines of turkeys. Poult. Sci. 76:217-226.
- BAYYARI,G.R.et al. 1997. Effect of the genetic selection of turkeys for increased body weight and egg production on immune and physiological responses. Poult. Sci. 76:289-296.
- NOBLE,D.O. & NESTOR,K.E. 1997. Beak trimming of turkeys. 2. Effects of arc beak trimming on weight gain, feed intake, feed wastage, and feed conversion. Poult. Sci. 76:668-670.
- CHRISTENSEN,V.L.et al. 1997. Effects of an oxygen-enriched environment on the survival of turkey embryos between twenty-five and twenty-eight days of age. Poult. Sci. 76:1556-1562.
- EMMERSON,D.A.et al. 1997. Ornithine decarboxylase activity in muscle, liver, and intestinal tissue of turkeys during a short-term feed withdrawal and following refeeding. Poult. Sci. 76:1563-1568.
- CHEN,S-E.et al. 1997. Characterization of plasma and yolk very low density lipoproteins (VLDL) from three lines of laying Japanese quail selection for plasma yolk precursor for 32 generations. Poult. Sci.76
- HUGHES,J.D.,JR.et al. 1997. Skeletal development of weight-selected lines of turkeys. Poult. Sci. 76 (Suppl.1):34.(Abstr)
- LI,Z. et al. 1997. Mitogenic and antibody responses of turkey lines selected for increased body weight. Poult. Sci. 76
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Progress 01/01/96 to 12/30/96
Outputs
A line (E) of turkeys selected long-term for increased egg production was backcrossed to a line (F) selected long-term for increased 16-wk body weight (BW) (BC1 crosses) and to a commercial sire line (BC2 crosses). The BW of the F and commercial sire lines were about twice as large as that of the E line. Egg production of the E line was more than double the egg production of either of the sire lines. Large gains in BW and breast width were observed in both backcrosses. Based on additive genetic variation, gains in BW were less than expected in the first generation for females in the BC1 and for both sexes in the BC2. Values observed for males of the BC1 were similar to expected values at 8 and 16 wk and larger than expected at 20 wk of age. Slower than expected BW gains in Generation 1 may have been attributable to the small egg size or E females. After Generation 1, BW at 16 and 20 wk of age was equal to or greater than expected. Egg production was reduced in both
backcrosses relative to the E line. Fertility and hatchability were reduced relative to the E line by backcrossing in BC1 but not in BC2. Results suggest that limited repeated backcrossing of a dam line to a sire line may be an economically feasible method to greatly increase BW of dam lines without unduly sacrificing reproduction capability.
Impacts
(N/A)
Publications
- NESTOR, K.E., BACON, W. L., ANTHONY, N.B. and NOBLE, D.O. 1996. Divergent selection for body weight and yolk precursor in Coturnix coturnix japonica. 10. Response to selection over thirty generations. Poultry Sci. 75:303-310.
- NESTOR, K.E., BACON, W.L., ANTHONY, N. B., and NOBLE, D.O. 1996. Divergent selection for body weight and yolk precursor in Coturnix coturnix japonica. 11. Correlated response over thirty generations. Poultry Sci. 75:472-477.
- NESTOR, K.E., SAIF, Y. M., ZHU, J., NOBLE, D.O. and PATTERSON, R.A. 1996. The influence of major histocompatibility complex genotypes on resistance to Pasteurella multocida and Newcastle disease virus in turkeys. Poultry Sci. 75:29-33.
- NESTOR, K.E., NOBLE, D. O., ZHU, J., and MORITSU, Y. 1996. Direct and correlated responses to long-term selection for increased body weight and egg production inturkeys. Poultry Sci. 75:1180-1191.
- ANTHONY, N.B., NESTOR, K. E., and MARKS, H.L. 1996. Short-term selection for four-week body weight in Japanese quail. Poultry Sci. 75:1192-1197.
- BACON, W.L. et al. 1995. Very-low density lipoprotein (VLDL) metabolism is not different in laying turkey hens with different growth rates and egg production. Poultry Sci. 74(Suppl.1):40.
- CHRISTENSEN, V.L. et al. 1995. Altering incubation periods of lines of turkeys selected for rapid growth and the resultant carbohydrate metabolism and surviva.
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Progress 01/01/95 to 12/30/95
Outputs
Progress is continuing in the lines of turkeys selected long-term for increased egg production (E line) & for increased 16-wk body weight (F line). The realized heritabilities (h2) +- SE were .34 +- .02 (17 generations) & .26 +- .13 (9 generations), resp., for 180-d and 250-d egg production in E. In F, h2 of 16-wk body weight (28 generations) was .26 +-.01. The genetic correlation of body weight & egg production changed with selection in E & F, varying from 0 to strongly negative & fluctuated between these extremes in both lines, even though they started from different base populations & selection criteria differed. A condition termed "early poult flipover" has developed in the E line. With this condition, poults fall on their back & have difficulty righting themselves resulting in high mortality. In Japanese quail lines divergently selected long-term for 4-wk body weight (HW, LW) & plasma yolk precursor (total plasma phosphorus) during the early part of the egg
production period (HP, LP), realized h2 declined over 30 generations. The overall h2 was .32 +-.01, .22 +- .02, .24 +- .01, & .23 +- .02, resp., for HW, LW, HP, & LP. Egg production declined in HW, LW, & HP.
Impacts
(N/A)
Publications
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Progress 01/01/94 to 12/30/94
Outputs
During 1994 an experiment was conducted to study the effects of range and confinement rearing on body weight, leg bone growth, mortality, behavior, and walking ability of four experimental lines of turkeys. Randombred control lines RBC2 and RBC3 were utilized, as were a line of turkeys selected for increased 16- week body weight (F), and a line selected for increased 16-week shank width (FL). Preliminary evidence suggested the presence of line-by-environment interactions. Birds were reared to 8 weeks of age in confinement housing. At 8 weeks of age, half the birds from each family were moved to range rearing. Line-by-environment interactions were present only for walking ability. The general lack of line-by-environment interactions indicates that rearing environment can be altered without affecting interpretation of results from the selection experiment. Line differences in growth traits were consistent with previous reports. Across lines and sexes, 16- and 20-week
body weights were .57 and .96 kg, respectively, heavier in range-reared than in confinement-reared birds, with the magnitude of environment effects larger for males than for females. Lines differed in some behaviors with RBC2 birds having shorter eating bouts and more steps taken per walk bout than the other lines. Lines also differed in tonic immobility (TI) with Lines RBC2 and FL requiring fewer inductions and having shorter duration of TI than Line F. Line RBC3 was intermediate to and did not differ from the other lines.
Impacts
(N/A)
Publications
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Progress 01/01/93 to 12/30/93
Outputs
During Generations 19 through 26, females of Japanese quail lines selected solely (HW) or partly (HW-HP; HW-LP) for increased 4-week body weight, selected for decreased 4-week body weight (LW) and from the corresponding randombred control (R1) were surveyed for the incidence and size of smooth muscle tumors. Laying hens were examined after about 170 days of egg production (240 days of age). The frequency and weight of the smooth muscle tumors were greater from the large-bodied lines than from Line R1. The tumors were always located in the dorsal and ventral ligaments of the oviduct in the region of the magnum. No tumors were detected in LW females. Based on linear regression of response on generations, tumor frequency was increasing in Line HW-LP while tumor weight was decreasing. Tumor weight was increasing in HW. No other significant changes in tumor frequency or size were noted across generations. Weight of the tumors did not influence egg production. Tumor
presence did not appear to affect mortality during the laying period. These lines may serve as a useful animal model for the study of human smooth muscle tumors. Response to selection is continuing in turkey lines selected long-term for either high egg production (E line) or increased 16-week body weight (F line) relative to their respective randombred controls. The E and F lines differed in thyroid function during incubation of eggs. The E and F lines also differed in level of thyroid hormones during parts of incubation period.
Impacts
(N/A)
Publications
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Progress 01/01/92 to 12/30/92
Outputs
Two randombred control lines were surveyed for the presence of major histocompatibility complex (MHC) haplotypes. Four functional different haplotypes were found and individuals homozygous for these haplotypes were obtained by inbreeding. Individuals with the four MHC haplotypes were challenged with Pasteurella multocida. No differences in mortality were observed among the four haplotypes and the average mortality observed for each haplotype was less than that expected from the randombred control populations from which the MHC haplotypes were obtained. Fat (F) and Lean (L) Japanese quail lines were developed using a restricted selection index which attempted to hold body weight constant. A stabilized control (SC) line was maintained in such a manner to hold body weight constant. The base population for the F, L, and SC lines was a line (HW) selected long-term for increased 4-wk body weight. Although an attempt was made to hold body weight constant, the F line was
heavier and the L line was lighter than the SC line. However, changes in body weight were not major. Response to selection for fatness was greater than the response to selection for leanness. The incidence of smooth muscle tumors was determined in the HW line, its randombred control (R1), two sublines of HW (HW-HP and HW-LP) and a subline of R1 selected for decreased 4-week body weight (LW). Incidence and size of tumors were larger in the HW, HW-HP and HW-LP than in the R1 line. No tumors were observed in the LW line.
Impacts
(N/A)
Publications
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Progress 01/01/91 to 12/30/91
Outputs
Developmental patterns of tissues ornithine decarboxylase activity (ODA) and nucleic acid concentrations were studied in a randombred control population (RBC2), a subline of Line RBC2 selected long-term for increased 16-week body weight (F) and a commercial sire line (C). Lines F and C were similar in body weight but Line C had greater breast weight than Line F. Lines F and C were heavier and had greater breast weight than Line RBC2. Tissue ODC activity reached its highest level on Day 2 post-hatch and declined rapidly through 13 days of age and remained low through 144 days. Tissue ODC activity of liver tissue was greater than that of either breast or leg muscle. Line C had greater ODC activity than Line RBC2 but Line F was not different from Lines C or RBC2. There was an age by line interaction resulting from Line C having higher tissue ODC activity only at 2 and 8 days of age. The DNA content of muscle tissue was greatest at hatch and declined to baseline values by
55 days of age. Muscle from Lines F and C had a lower DNA content than that of Line RBC2. The RNA content was similar across lines. The RNA content was greater for breast muscle than for leg muscle during the early post-hatch period.
Impacts
(N/A)
Publications
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Progress 01/01/90 to 12/30/90
Outputs
Reciprocal crosses were made between a commercial sire line and a line selected for 19 generations for increased 16-wk body weight. Progeny of this cross displayed positive heterosis for 16- and 20-wk body weights and negative heterosis for body weight at sexual maturity. Crossbred progeny also exhibited heterosis for walking ability. Heterosis was greater for reproductive traits than for growth traits. Improvements in the rate of egg production and reductions in broodiness for crossbred females resulted in egg production which exceeded that of the parental populations by approximately 20 eggs per hen. The selection response for Generations 10 through 29 of a line selected for increased 180-day egg production (E) was evaluated. An apparent plateau in egg production was determined to be the result of a negative environmental trend. When data were adjusted for this environmental trend, it was determined that egg production had continued to increase by approximately 2.5
eggs per generation. Increases in egg production were achieved both through increases in the rate of egg production and reductions in broodiness. Both 8- and 16-wk body weight declined in a curvilinear manner in E.
Impacts
(N/A)
Publications
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Progress 01/01/89 to 12/30/89
Outputs
Nineteen generations of selection for increased (HW) or decreased (LW) 4-wk bodyweight & increased (HP) or decreased (LP) total plasma phosphorus were summarized for body weight (early and late in the egg production period, wet and dry liver weight) and reproductive traits (egg production and weight, shell, albumen and yolk weights and number of follicles in rapid development). Similarly, 11 generations of selection of sublines derived from original Lines HW and LP were also analyzed. Sublines were maintained through selection of males for increased 4-wk body weight and females for the respective high (HW-HP) or low (HW-LP, LP-HW) plasma phosphorus. The randombred control (RBC1) was stable for all measured traits except late body weight, egg and respective component weights, and ova number which increased over generations. Line HW increased over generations from RBC values for all traits except dry liver and follicle number. Likewise, Line LW decreased with
generations for all traits except wet liver and albumen weight and follicle number. Line HP differed from RBC1 for only dry liver, egg and yolk weights which declined over generations. Line LP was consistent with the RBC1 except for decreases in dry liver, egg and albumen weight despite increases in follicle number over generations. The sublines responded similarly to their line of origin differing only in magnitude of response.
Impacts
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Progress 01/01/88 to 12/30/88
Outputs
Several tumors were observed during a routine survey of the ovarian follicular development of Japanese quail lines selected for increased (HW) or decreased (LW) 4-wk body weight, increased (HP) or decreased (LP) plasma yolk precursor (total plasma phosphorus), their corresponding randombred control (R1), and sublines of HW in which the males were selected for increased 4-wk body weight and the females for increased (HW-HP) or decreased (HW-LP) plasma yolk precursor. Since the tumors appeared to be associated with growth rate, data were collected on the frequency of tumor occurrence and the tumors were studied in detail. Comparisons were made of hens at approximately 250 day of age. The tumors were located in the ligaments of the oviduct. These tumors were identified as leiomyomas and leiomyosarcomas. In the 18th generation of HW (9th generation of sublines) tumors were observed in 53 to 80% of females from the large bodied lines (HW, HW-HP and HW-LP) and in only
39% of the R1 females. Line R1 served as the base population for HW. All of the tumors observed in R1 were small (.35 g) and lacked vascularity while many of these in the large bodied lines were highly vascularized and larger (range in average weight from 2.1 to 4.6 g). In the 19th generation of HW, the incidence of tumors in the large bodied lines ranged from 64 to 83% compared to 22% for the R1 line. No tumors were observed in the LW line. The results indicate that the frequency of tumor occurrence is associated with genetic changes in body weight.
Impacts
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Progress 01/01/87 to 12/30/87
Outputs
Differences in mortality following a natural outbreak of fowl cholera were observed between a turkey line (E) selected for increased egg production and its randombred control population (RBC1) which served as the base population of E. Mortality in the E line was almost double that of RBC1. The antibody response of the E and RBC1 lines to Newcastle disease virus (NCDV) and of Pasteurella multocida (PM) was studied. Line RBC1 had significantly higher maternal antibodies to NCDV at three weeks of age than Line E. The RBC1 line had significantly higher levels of antibodies in response to vaccination with both NCDV and PM singly or together and maintained the antibody titers longer than Line E. When challenged with PM organisms, the E line had about twice the mortality as the RBC1 line. The mortality in a turkey line (F) selected for increased body weight was higher than its randombred control (RBC2) following natural outbreaks of Erysipelas and fowl cholera. The
RBC2 line served as the base population for F. However, after vaccination with NCDV or PM, there was no major difference between the F and RBC2 lines in primary or secondary response. The growth curve of Line E may be changing relative to the RBC1 line. The body weight at 8 and 16 weeks of age is declining in the E line relative to the RBC1 line while there is no charge in body weight at 20 weeks of age.
Impacts
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Progress 01/01/86 to 12/30/86
Outputs
Response to selection for increased egg production (EP) in the E line of turkeyshas plateaued. During the last 4 generations of selection, EP of E females averaged 138 to 144 eggs per hen in a 180-day period. This was 70 to 71 eggs superior to the randombred control which served as the base population. The long-term growth-selected line (F) of turkeys has decreased in walking ability relative to its control. A subline (FL) of F was established by mass selecting only for increased shank width at the narrowest point in an attempt to increase the relative amount of leg bone. Selection was effective in increasing shank width and the relative amount of the tarsometatarsal bone but there was no significant change in either the tibiotarsal or femur bones. Body wt gains comparable to those observed in F males were observed in FL males as a correlated response to selection. However, females of FL have not gained significantly in body wt resulting in a line x sex
interaction. Walking ability of FL males was superior to that of F males even though body wt was similar. EP has declined to the same extent relative to randombred controls, in lines of Japanese quail selected for increased 4-wk body wt (HW) or increased plasma level of yolk precursor (HP). Two sublines of HW were started by continuing to select the males for increased 4-wk body wt while selecting the females for either increased (HW-HP) or decreased (HW-LP) yolk precursor level.
Impacts
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Progress 01/01/85 to 12/30/85
Outputs
Changes in total egg mass (average egg wt x total egg production) and biologicalefficiency (ratio of egg mass to metabolic body wt) were measured in generations 11-24 of a line (E) of turkeys selected for increased egg production and generations 1-18 of a turkey line (F) selected for increased 16-wk body wt. Total egg mass increased in E even though egg wt decreased. Egg production increased greatly (3.9 eggs/generation) in E. Biological efficiency increased in E at a rate slightly lower than the increased observed in total egg production (.143 delta vs .128 delta per generation). In F, egg wt increased, egg production decreased, while egg mass exhibited a nonsignificant decrease. Biological efficiency of egg production decreased in F. In both E and F, a change in egg production of one egg resulted in a similar change in biological efficiency (.016 kg/kg) even with a large difference in average body wt (7.21 kg in E; 13.65 kg in F) and egg wt (74 g in E; 95 g in F).
Females of E have been repeatedly backcrossed to males of F. This was done to determine if body wt of female turkey lines could be increased rapidly without greatly influencing egg production. In the first cross, egg production and male body wts were at the expected level based on additive genetic variation. Female body wt was less than expected. In future backcrosses, body wt during the growing period was at the expected level while egg production did not decrease as much as expected.
Impacts
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Progress 01/01/84 to 12/30/84
Outputs
Response to long term selection of 16 wk body wt appears to be declining in the F line. Recent increases in body wt of this line have been associated with a decrease in walking ability. There has been no further decline in egg production. There appears to be a cessation of response to selection for increased egg production in the E line. Egg production of E relative to its control has not changed in the last 3 generations (21-24) of selection. There has been no loss in body wt in E since the 6th generation of selection. Turkey lines selected divergently for estrogen level shortly after the beginning of lay exhibit a difference in egg production. Egg production of the high estrogen line is higher while that of the low estrogen line is lower than the corresponding control. Japanese quail lines selected for increased 4-wk body wt (HW) and high yolk precursor (HP) had decreased egg production relative to the control (R1) from which the lines were originated.
Selection for decreased body wt (LW) or decreased yolk precursor (LP) had no significant effect on egg production. A subline (HW-LP) of HW in which the males were selected for increased 4-wk body weight and the females were selected for decreased yolk precursor had similar egg production to R1. Another subline of HW, HW-HP (males selected for growth, females for high yolk precursor) had egg production lower than the R1 line. Body wt. at 4 wks of age and yolk precursor at the beginning of lay is not correlated in the HW, HP and LP lines.
Impacts
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Progress 01/01/83 to 12/30/83
Outputs
The leg condition and ability to walk has declined in recent generations of a long-term growth selected line (F) of turkeys. A subline (FL) of F selected entirely for shank diameter has better legs even though body wt is not greatly different. There is no difference in egg production between F and FL, but both lines are lower than the control population. Hens from the F line lay a substantial number (>5% of total eggs) of shellless eggs. Genetic increases in 16-wk body wt had no effect on broodiness but significantly decreased intensity of lay. Natural disease outbreaks of fowl cholera and erysipelas occurred during the year. Fowl cholera was diagnosed only in breeder males while erysipelas occurred only in breeder females. Mortality during the fowl cholera outbreak was about twice as large in the long-term selected egg line (E) than in its corresponding randombred (RBC1). However, no mortality due to erysipelas occurred in E and RBC1 whereas F exhibited the
highest mortality. Mortality from fowl cholera was also high in F. There were no differences in mortality occurring during both diseases between the high and low estrogen lines and their randombred control. These results suggest genetic variation in resistance to fowl cholera and erysipelas. Repeated backcrosses of E line females to F line males indicate that the genetic variation in 16-wk body wt., 180-day egg production and breast width is mostly additive.
Impacts
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Progress 01/01/82 to 12/30/82
Outputs
Response to selection in continuing in the line of turkeys selected long-term for increased 180-day egg production. During generations 21 and 22, the average egg production increased 2 eggs/hen. The current average egg production of the E is 144 eggs. There has been no further loss in body wt. in E. Egg wt has declined 9 to 10 grams in E. Mortality to 8 wks of age has been increased in E. The rate of response to selection has declined in recent generations of a line (F) selected long term for increased 16-wk. body wt. A part of this decline is attributed to an increase in frequency of bad legs in F. A subline of F which was selected 3 generations for increased shank diameter exhibited better legs than F. No further loss in egg production has occurred in F. Crosses of F males and E females resulted in progeny which were intermediate in body wt., breast width and egg production between the two parental strains. Tandem selection for increased egg production and
increased 16-wk. body wt. is being studied. The tandem selected line was initiated after 11 generations of selection in F. Results in the second cycle of selection indicate that this is not an efficient method of improving both traits. Three generations of selection were required to recover all of the loss in egg production observed in F. However, further generations of selection for increased 16-wk body wt.
Impacts
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Progress 01/01/81 to 12/30/81
Outputs
The genetic relationship between body weight during the growing period and egg production of turkeys changed during the course of a long term selection study. In a line (E) selected solely for increased egg production, there was little relation to growth during the first four generations even though egg production increased greatly. In the next two or three generations, body weight declined greatly in E. Further increases in egg production in the E have not resulted in changes in body weight. Similar results were obtained when selection was practiced for increased 16-week body weight in that there was little association between body weight and egg production in the first 3 generations, followed by a strong negative correlation the next few generations and then no relation in later generations. Selection for increased egg production has not changed the average level of prolactin in the blood over the entire laying period. However, for individual hens, the peak
level at the expected time of broodiness was greatly reduced in the E line. Many E line hens exhibit signs of broodiness but continue laying. These hens lay slightly more eggs than E hens which do not exhibit broodiness signs. Crosses of the large growth line males with egg line females resulted in an offspring which was intermediate in body weight and breast width. Hatchability of eggs from the cross was improved. Mortality during the growing period was reduced in the cross.
Impacts
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Progress 01/01/80 to 12/30/80
Outputs
The amount of abdominal fat was measured at 20 weeks of age in a strain selectedfor increased 16-week body weight (F) and its random bred control (R2). After 14 generations of selection in F, body weight averaged 10.68 and 8.27 kg, respectively, for F and R2. The abdominal fat pad was larger in F than R2 both as an actual weight (91 versus 41 grams) and as percent of live weihgt (.91 versus .53). The abdominal fat pad was larger in females (86 gms) than in males (45 gms). The F strain and a strain (E) selected for 18 generations for increased egg production were compared with their corresponding random bred controls for response to cold stress at 4 weeks of age. Genetic increases in egg production were associated with decreases in body weight and increases in plasma corticosterone level after cold stress. Conversely, genetic increases in body weight were associated with decreased egg production and plasma corticosterone level after cold stress. Eggs from hens of
the various genetic strains of turkeys were rated for amount of pimpling. Pimpling score exhibited little variation among strains which suggests little genetic variation. Pimpling increased with length of hatching period. Body weight of F and R2 strain females and a subline of F were restricted by feeding ad libitum a high fiber diet (69% oat hulls) from 16 weeks until housing in the laying pens. The amount of body weight restriction varied slightly between strains. There was no beneficial effect on egg production.
Impacts
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Progress 01/01/79 to 12/30/79
Outputs
Selection has been effective in establishing lines of Japanese quail which have high (HW) and low (LW) body wt and high (HP) and low (LP) levels of total blood phosphorus (P) after the first 2 wks of production. After 4 generations of selection, the 4-wk body wts of the random bred control (R1), HW and LW were 86, 97 and 69 g, respectively. The total blood P for R1, HP and LP was 729, 996 and 582 Mug/ml, respectively. Genetic increases in body wt were associated with a decrease in egg production. After 2 generations of selection, the average 120-day egg production of a low egg line has decreased by 5 eggs per hen while the egg production of the high egg line has increased by only 2 eggs per hen. Egg production of a turkey line selected for a low level of total estrogen soon after first egg decreased greatly (-16.6 eggs per hen) relative to the control line in the last generation of selection. The line selected for a high level of total estrogen gained 2.5 eggs at
this time. The loss of egg production in the low estrogen line appeared to be the result of the hens going out of egg production before the end of the 180-day production period. Selecting a turkey line (F) solely for increased 16-wk body weight resulted in a large loss (15 eggs/hen) in 120-day egg production. Two generations of selection for increased egg production in a subline of the F line (FE) resulted in a gain of 9.3 eggs of the lost production with only a slight loss in 16-wk body wt (345 g for females).
Impacts
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Progress 01/01/78 to 12/30/78
Outputs
Response to selection for increased total egg production plateaued or exhibited a decline from the 7th to 9th generations of selection. This was attributed to an increase in broodiness in the high egg (E) line. From the 10th to 18th generations of selection, hens of the E line were not treated for broodiness whereas the randombred control hens were treated as before. After this change, there was a large increase in egg production of the E line relative to the control. There was no further reduction in body weight. Broodiness decreased and intensity of lay greatly increased during this time. The rate of response to light also increased in the E line. Selection was effective in establishing a line difference in fertility in the R (selected for increased fertility) versus randombred control line during the first 4 generations of selection. Realized heritability of percent fertility was .70 plus or minus .36. Gains in fertility were due to changes in the female for
there were no major changes in production or fertilizing ability of R line semen. Fertility was positively correlated with egg production, clutch length and, perhaps, with hatch of fertile eggs and number of poults produced per hen. There were negative genetic correlations between body weight at various ages and fertility. There was little association between fertility and egg weight, number of clutches, rate of lay, days to first egg and broodiness traits.
Impacts
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Progress 01/01/77 to 12/30/77
Outputs
The realized heritability of average clutch length and total days broody were .24 plus or minus .10 and .31 plus or minus .12, respectively. The realized genetic correlation between these two variables was minus .60 and minus .31 based on the clutch and broody lines, respectively. Egg production increased in both lines with the increase being greater in the broody line. Body weight declined in the broody line with no change in the clutch line. Further data indicate that the increased egg weight obtained by selection for increased 16-week body weight is due entirely to increased amount of albumen. The results of reciprocal backcrosses indicated that genes responsible for black, gray, slate and black-winged bronze plumage color had no significant effect on body weight at 8, 16 and 24 weeks of age. The bourbon red, spotted and dark brown genes reduced body weight. The gray, black, slate, black- winged bronze and dark brown genes did not influence egg production while
egg production was reduced by the red gene. The gray gene improved while the red, black, slate and dark brown genes had no effect on semen production. The black-winged bronze gene reduced semen yield but had no effect on sperm concentration. Four generations of randombreeding without selection after eleven generations of selection for a high (HL) and low (LL) level of plasma corticosterone after cold stress resulted in further separating of the HL and LL in response to cold stress and body weight.
Impacts
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Progress 01/01/76 to 12/30/76
Outputs
Selection for increased 16-wk body wt resulted in consistent gains in 16-wk bodywt. The gain in wt was associated with a major reduction in production of settable eggs. Even though egg production was decreased, the number and total wt of the ova in rapid development in the ovary were increased. Ova in the 16-wk line were lost by 1) atresion after rapid development had once started, 2)by ovulation in the body cavity and not being picked up by the oviduct, and 3) by production of abnormal eggs. There was a highly significant increase in egg wt which accompanied the increase in body wt. The increased egg wt was the result of an increase in the wt of albumen with no change in wt of the yolk. Estimates of realized genetic correlations between 16-wk body wt and total egg production, poults produced per hen and measures of intensity of lay were all large and negative. There were no significant correlations between 16-wk body wt and measure of broodiness. Selection for
increased egg production in generations 10 through 16 when no broody hens were treated resulted in large gains in egg production with no further loss in body wt. Selection for increased egg production over 16 generations did not change the number or total wt of ova in rapid development in the ovary but reduced the loss of ova during the egg production process. Selection for increased egg production resulted in decreased egg wt due to similar
Impacts
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Progress 01/01/75 to 12/30/75
Outputs
Artificial selection in the 2 lines of turkeys developed by selection for high and low blood corticosterone levels after cold stress at 4 weeks of age was discontinued in 1973 after 10 generations. Randombreeding in 1974 and 1975 resulted in no apparent drift in plasma corticosterone level after cold stress but the superiority of the low line in egg production and fertility has been lost while superiority in body weights was maintained. Further data from reciprocal crosses indicated that the genes responsible for gray color, c(g), did not improve egg production and growth rate but improved semen yield, sperm concentration and total sperm per ejaculate. Recent evidence suggests that the bourbon red gene (r) may have a harmful effect on egg production while the blackgene (B) may reduce growth rate. Selection for increased fertility resulted in gains for the first 2 generations of selection with no further gains the next 2 generations. This was accomplished with no
apparent change in semen quality. Egg production of the fertility line, after an initial decrease, was similar to the corresponding randombred control after 4 generations of selection. There was a slight decrease in body weight of the fertility line initially but there was no evidence of further reduction with selection. Selection for increased average clutch length in one line and decreased total days lost from broodiness in another resulted in increased egg production in both lines. The gains in eggproduction averaged 2 and 5 eggs
Impacts
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Progress 01/01/74 to 12/30/74
Outputs
Heritability of viability from 0 to 4 weeks of age averaged .080n.014 with a confidence interval (P<.01) of .044 to .094. The heritability estimate of viability from 0 to 8 weeks of age averaged .117n.008 with a confidence interval(P<.01) of .096 to .138. The magnitude of the heritability estimates increased with increases in mortality. Mortality during the early growing period was increased in the egg line and decreased in the line selected for low corticosterone level after cold stress. Genetic increases in 16-week body weight and semen yield did not influence poult mortality. Interactions between lines and years were frequently observed both with and without line differences in mortality indicating genotype-environmental interactions. Selection for increased fertility has resulted in increased fertility in the female without noticeable change in semen characteristics of the male.
Impacts
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Progress 01/01/73 to 12/30/73
Outputs
Response to selection for increased 180-day egg production in the egg (E) line was zero or negative from the 7th through the 9th generations of selection. It was observed that intensity of lay and broodiness were increasing resulting in no gain or possibly a loss in total number of eggs produced. Beginning in 1970,no broody hen management system was used for E line hens. This resulted in a loss of approximately 10 eggs per hen. However, selection response for total egg production increased greatly resulting in a total gain of 17 eggs over the next 4 generations of selection. This gain was accomplished without any furtherloss in body weight. A comparison was made of yolk production of E line and randombred control line hends. Selection for high egg production reduced body weight and the number of ova in rapid development with little change in total weight of those ova. A large number of ova are apparently lost in the control line by regression of developing
follicles.
Impacts
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Progress 01/01/72 to 12/30/72
Outputs
Evidence obtained from several selected lines indicates that weight of turkeys at older ages is not genetically correlated from broodiness traits but is strongly negatively correlated with rate of lay. Large gains in egg production were observed without loss in body weight in the first few generations of selection in a line selected solely for increased egg production. This gain resulted primarily from a reduction in the amount of broodiness with little change occurring in rate of lay. In later generations clutch length increased and a large loss in body weight occurred. Selection for increased egg production and increased 16-wk body weight by use of a selection index which gave three times the emphasis on body weight as on egg production resulted in gains in both traits during the first few generations when broodiness was being reduced. In later generations, the gains in egg production were lost but continued gains in body weight were obtained.
Impacts
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Progress 01/01/71 to 12/30/71
Outputs
Selection for increased production in the egg line when no broody hen managementsystem was used to "break up" broody hens resulted in further genetic gains in egg production after a number of generations in which little or no gains were observed. Two sub-lines were developed from the large bodied randombred controlline on the basis of increased clutch length and decreased broodiness. These lines were established to determine if the decrease in body weight in the egg line was the result of changes in either of these egg production traits. After one generation of selection, there was no apparent response in either line. Theproduction of defective eggs was greater in meat type turkeys than in egg type turkeys when housed in cages. The frequency of broken eggs, membrane eggs and soft-shelled eggs was high in the meat type turkey. The frequency of double-yolked and "slab-sided" eggs did not differ significantly between the twotypes. Further analyses of blood indicate
that the meat and egg type turkeys have a similar blood level of the low density fraction of lipoprotein which is also found in egg yolk.
Impacts
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Progress 01/01/70 to 12/30/70
Outputs
The egg production in recent generations of the egg line has declined relative to the randombred control. This was attributed to an improvement in egg production of the control line resulting from environmental cause and an increase in broodiness in the egg line. A major loss in body weight was observed during this period of declining egg production. This was attributed toa large increase in clutch length in the egg line. The loss in body weight observed in the egg line was recovered by one generation of selection for increased 16-week body weight. Further studies of yolk production of large meat-type turkeys indicate that late in the laying season, meat-type birds lose more of their yolks through atrophy and yolks developing as pairs than egg-type turkeys. A preliminary analysis of the blood indicated that the meat-type turkey had a higher blood level of low density fraction of lipoprotein which is also found in egg yolk. Further selection in the semen line has
resulted in additional decreases in egg production and growth rate. Semen yield continued to increase.
Impacts
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Progress 01/01/69 to 12/30/69
Outputs
No further gains in egg production were obtained in the line selected solely foregg production. A subline was initiated from the egg line on the basis of selection for increased 16-week body weight in 1968. All the loss in body weight at 16 weeks of age observed in the egg line in previous generations was recovered in one generation with a loss of only two eggs per hen for a 180-day production period. Further selection in the index line for both increased egg production and increased 16-week body weight resulted in a large increase in eggproduction but only a slight increase in 16-week body weight. The yolk production of large meat type turkeys was found to be superior to that of the egg line. The number of days required for rapid development of the ova (yolk) in the ovary did not differ between the meat and egg type turkeys. However, females of the meat strain had more ova in rapid development (11.4 versus 9.6) and a larger total weight of ova in rapid
development (137.6 versus 105.4 grams)than the egg strains. This indicates that the meat type turkeys lost some yolkssomewhere in the egg production process since the egg production of meat type turkeys was less than that of the egg type. The line selected for increased semen yield showed a further increase in semen yield but had no further gain in egg production.
Impacts
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Progress 01/01/68 to 12/30/68
Outputs
Selection for both increased egg production and increased 16-week body weight byan index resulted in increases in both egg production and body weight. The gains in body weight were less than that observed in a line selected only for increased 16-week body weight. No further gains in egg production were obtainedin the line selected solely for increased egg production. The large loss of body weight observed in the egg line in the seventh generation was still evidentin the eighth generation. Further gains in egg production and semen yield were observed in a line selected for increased semen yield. However, the increased growth rate observed in this line in earlier generations was not present in 1968. The results of this experiment indicate that turkey breeders can improve reproduction by selecting for egg production alone or in combination with body weight. Index selection for both egg production and body weight appears to be the method of choice.
Impacts
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Progress 01/01/67 to 12/30/67
Outputs
A rapid decrease in growth rate and no further gain in egg production was observed in the seventh generation of the line selected for increased egg production. In previous generations of this line, substantial gains in egg production have been made with little loss in growth rate. This indicates that the genetic relationship between egg production and growth rate may be changing in this line. The line selected for increased semen yield still exhibited greater growth rate and egg production than the corresponding randombred controlline, but showed no further increases in the second generation over that obtained in the first generation. Semen yield, fertility and hatchability did increase in the second generation of selection in this line. A line selected for both increased egg production and increased 16 week body weight by means of an index exhibited gains in both trait the first generation, but the gains in body weight were not as great as those observed in a
line selected solely for increased 16 week body weight.
Impacts
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