Progress 10/01/02 to 09/30/07
Outputs
OUTPUTS: The breeding program to study genetic influence on embryonic mortality continued with the mating of Suffolk (S) and Polypay (P) rams to blackface (BF, primarily S) and whiteface (WF, primarily P) ewes to produce additional BF, WF and reciprocal cross lambs. The database continues to grow for examination of maternal and fetal effects on embryonic loss. Yearling BF and WF female progeny entered the breeding flock as replacements for aged ewes, allowing for estimation of year as well as ewe age effects. Crossbred yearling ewes from the embryo mortality trial (above) were added to an existing reduced input (RI) management system flock where they were randomized within genotype for single sire mating with either Polypay or White Dorper (D) rams. RI mating was delayed to produce lambs later in the spring when weather conditions were expected to be more conducive to high lamb survival under pasture lambing. Overall project results show a consistent negative impact of Suffolk
breeding on embryo survival. Use of Suffolk sires on twin-ovulating ewes resulted in a reduction of about 0.1 lambs per ewe lambing compared to use of Polypay sires; this effect was consistent regardless of ewe genotype. Progeny of Polypay and White Dorper sires showed similar lamb survival and P-sired lambs were consistently larger at birth. Genotypic differences in growth thereafter were inconsistent and may be a reflection of sire sampling. When F1 progeny of the two sire breeds were backcrossed to their respective sire breeds, Dorper halfbred ewes showed a dramatically lower litter size (1.71 vs. 1.37). Trial results have been disseminated through presentation and discussion at regional research meetings, local extension meetings, and annual meetings of the state (Oregon) Sheepgrowers Association.
PARTICIPANTS: The project allowed training opportunity for many undergraduate employees and served as the basis for several undergraduate research projects and two MS theses. A student sub-project was also the basis for the 2007 national FFA Star Agriscience Award. In addition, sheep from the project were used in undergraduate Sheep Production Systems courses and industry lambing schools, and were the center-point for open-barn lambing which attracts over 5,000 visitors (mostly children and their parents/teachers) annually.
TARGET AUDIENCES: The primary target audience has been commercial sheep producers. The results have also been shared with other researchers in collaborative regional research projects.
Impacts
Documentation of the negative impact of Suffolk breeding has led to many producers considering alternative (primarily whiteface) ram breeds and has been instrumental in efforts to develop a synthetic alternative terminal sire breed. The RI results have shown the importance of female reproductive rate on net lamb production and have shown the limitations of the Dorper breed in such management systems despite their advantages in reduced shearing costs. Commercial producers considering introduction of Dorper breeding in their ewe flocks have largely refrained from doing so. At the same time, additional attention has been focused on the Polypay breed as a prime candidate for reduced input management systems.
Publications
- No publications reported this period
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Progress 01/01/06 to 12/31/06
Outputs
PROGRESS: 2006/01 TO 2006/12 The breeding program to study genetic influence on embryonic mortality continued with the mating of Suffolk (S) and Polypay (P) rams to blackface (BF, primarily S) and whiteface (WF, primarily P) ewes to produce additional BF, WF and reciprocal cross lambs. The database continues to grow for examination of maternal and fetal effects on embryonic loss. Yearling BF and WF female progeny entered the breeding flock as replacements for aged ewes, now allowing for estimation of year as well as ewe age effects. Crossbred yearling ewes from the embryo mortality trial (above) were added to a flock established the previous year to examine lamb production under a reduced input (RI) management system. RI ewes were randomized within genotype for single sire mating with either Polypay or White Dorper (D) rams to generate the second year class of females for future evaluation of lambing under spring pasture conditions with a minimum of supervision.
Analysis of data from the first RI lamb crop, born on pasture during an unusually wet spring, indicated an overall survival rate of .87 with survival of lambs from P and D sires being similar. Lambs from P sires were .8 kg heavier at birth; this difference increased to 1.7 kg at weaning (P<.05) and 5.9 kg by 11 months of age (P<.01).
Impacts
Sheep are excellent tools for harvesting forage and marketing it as high quality meat and wool. However, Oregon's sheep numbers are declining due to several factors including marginal industry profitability. Increasing reproductive efficiency is the surest means of making U.S. lamb competitive with imported lamb. It is anticipated that results of this study will show current producers how to increase productivity by 10% or more without significant change in production costs or management practices. If sheep derived from the Dorper breed (which sheds its wool and is reputed to be very hardy) prove successful under pasture lambing conditons, producers may also be able to increase profit margins by reducing shearing and expensive indoor lambing costs.
Publications
- Abdulkhaliq, A.M., H.H. Meyer, J.R. Busboom, and J.M. Thompson. 2006. Growth, carcass and cooked meat characteristics of lambs sired by Dorset rams heterozygous for the calipyge gene or Suffolk or Texel rams. J. Small Rum. Res. (In press).
- Meyer, H.H. and R.P. Scholz. 2006. Controlling Brachypodium Sylvaticum by sheep grazing. Ann. Rpt. WCC-039: Coordination of Sheep and Goat Research and Education Programs for the Western States.
- Meyer, H.H. and J.M. Thompson. 2006. Reduced input sheep production. Ann. Rpt. NCR-190: Increased Efficiency of Sheep Production. Meyer, H.H. and J.M. Thompson. 2006. Reduced input sheep production. Ann. Rpt. WCC-039: Coordination of Sheep and Goat Research and Education Programs for the Western States.
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Progress 01/01/05 to 12/31/05
Outputs
The breeding program to study genetic influence on embryonic mortality continued with the mating of Suffolk (S) and Polypay (P) rams to blackface (BF, primarily S) and whiteface (WF, primarily P) ewes to produce additional BF, WF and reciprocal cross lambs. Ewes were examined via laparoscopy to build the database on maternal and fetal genotype effects on embryonic loss. Yearling BF and WF female progeny entered the breeding flock as replacements for aged ewes. Concurrent research examining the effect of East Friesian (EF) genes on increasing milk production in a Polypay genetic background was completed. In general, it was found that 1/4 EF breeding increased milk production by about 5% with similar concomitant increase in weaning weight of twin and triplet lambs being reared. Supplementation of lactating twin and triplet-rearing ewes with whole corn while ewes were grazing ryegrass/white clover pasture did not increase milk production as measured by weeekly milking.
However, lambs being reared by supplemented ewes showed a growth response relative to those of unsupplemented ewes, probably due to lambs having access to the supplement intended forthe ewes. Remaining ewes from the EF trial were combined with yearling crossbred ewes from the embryo mortality trial (above) to form a flock to examine lamb production under a reduced input (RI) management system. RI ewes were randomized within genotype for single sire mating with either Polypay or White Dorper (D) rams to generate females for future evaluation lambing under spring pasture conditions with a minimum of supervision.
Impacts
Sheep are excellent tools for harvesting forage and marketing it as high quality meat and wool. However, Oregon's sheep numbers are declining due to several factors including marginal industry profitability. Increasing reproductive efficiency is the surest means of making U.S. lamb competitive with imported lamb. It is anticipated that results of this study will show current producers how to increase productivity by 10% or more without significant change in production costs or management practices. If sheep derived from the Dorper breed (which sheds its wool and is reputed to be very hardy) prove successful under pasture lambing conditons, producers may also be able to increase profit margins by reducing shearing and expensive indoor lambing costs.
Publications
- Fackrell, B.B. 2005. Effects of genotype, nutrition and progesterone on uterine efficiency in the ewe. M.S. Thesis. Oregon State University, Corvallis, OR 97331.
- Meyer, H.H. and B.B. Fackrell. 2005. Effects of genotype, nutrition and progesterone on uterine efficiency in the ewe. Ann. Rpt. NCR-190: Increased Efficiency of Sheep Production.
- Meyer, H.H. and J.M. Thompson. 2005. Reduced input sheep production. Ann. Rpt. WCC-039: Coordination of Sheep and Goat Research and Education Programs for the Western States.
- Meyer, H.H. and J.M. Thompson. 2005. Reduced input sheep production. Ann. Rpt. NCR-190: Increased Efficiency of Sheep Production.
- Meyer, H.H. and R.P Scholz. 2005. Controlling Brachypodium Sylvaticum by sheep grazing. Ann. Rpt. WCC-039: Coordination of Sheep and Goat Research and Education Programs for the Western States.
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Progress 01/01/04 to 12/31/04
Outputs
We have demonstrated that both maternal and embryo genotypes influence the success of embryo survival in multiple-ovulating ewes. Suffolk (S) and Polypay (P) rams were mated to blackface (BF, primarily S) and whiteface (WF, primarily P) ewes to produce WF, BF and reciprocal cross lambs. Among ewes conceiving to twin ovulations, WF ewes produced more lambs than BF ewes regardless of breed of mate. Likewise, regardless of genotype, ewes mated to P rams produced more lambs than those mated to S rams. Contrary to expectation, no evidence of embryo heterosis was observed, i.e. sire and dam genotype effects were additive. Ewes managed for reduced body condition showed lower embryonic efficiency regardless of genotype. Analysis of hormone levels continues in an attempt to elucidate the physiological basis of variation being observed. Concurrent research to increase milk production and associated lamb growth by incorporation of East Friesian genes into a prolific Polypay
background has shown a modest increase in both milk production and lamb growth rates without a concomitant loss in reproductive performance. There is no evidence that the increased milk production of EF crossbred ewes compromises their longevity in a commercial production situation.
Impacts
Sheep are excellent tools for harvesting forage, whether winter growth on saturated grass seed fields or invading weed species in forests, and marketing it as high quality meat and wool. However, Oregon's sheep numbers are declining due to several factors including marginal industry profitability. Increasing reproductive efficiency is the surest means of making U.S. lamb competitive with imported lamb. It is anticipated that results of this study will show producers how to increase productivity by 10% or more without significant change in production costs or management practices.
Publications
- Meyer, H.H,. Heade, Jill, and J.M. Thompson. 2004. Utilization of East Friesian breeding to increase lamb production: effect of ewe supplementation. Ann. Rpt. NCR-190: Increased Efficiency of Sheep Production.
- Meyer, H.H. and J.M. Thompson. 2004. Utilization of East Friesian breeding to increase lamb production: milk production and lamb growth. Ann. Rpt. WCC-039: Coordination of Sheep and Goat Research and Education Programs for the Western States.
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Progress 01/01/03 to 12/31/03
Outputs
We have demonstrated that both maternal and embryo genotype influence the success of embryo survival in multiple-ovulating ewes, but the physiological basis of genetic variation is unknown. A preliminary analysis of hormone levels at 14 days (the time of maternal recognition of pregnancy) and 21 days post-mating (time of embryo implantation) revealed no significant differences between ewes losing one or more potential embryos vs. ewes showing no loss. Previous research results have suggested that ewe body condition also plays a role in embryo success rates so that component has also been incorporated into the present trial to elucidate means of increasing ewe reproductive efficiency by reducing embryonic loss. Concurrent research to increase milk production and associated lamb growth by incorporation of East Friesian genes has shown a modest increase in both milk production and lamb growth rates. Ewes rearing either two or three lambs on spring pasture did not show a
positive response in either milk production or lamb growth when provided with concentrate supplementation.
Impacts
Sheep are excellent tools for harvesting forage, whether winter growth on saturated grass seed fields or invading weed species in forests, and marketing it as high quality meat and wool. However, Oregon's sheep numbers are declining due to several factors including marginal industry profitability. Increasing reproductive efficiency is the surest means of making U.S. lamb competitive with imported lamb. It is anticipated that results of this study will show producers how to increase productivity by 10% or more without significant change in production costs or management practices.
Publications
- Meyer, H.H. and J.M. Thompson. 2003. Comparison of Suffolk and Texel x Suffolk terminal sires. Ann. Rpt. WCC-039: Coordination of Sheep and Goat Research and Education Programs for the Western States.
- Thomas, D.L., D.F. Waldron, G.D. Lowe, D.G. Morrical, H.H. Meyer and R.A. High. 2003. Length of docked tail and the incidence of rectal prolapse in lambs. J. Anim. Sci. 81:2725-2732
- Meyer, H.H. and J.M. Thompson. 2003. Utilization of East Friesian breeding to increase lamb production. Ann. Rpt. NCR-190: Increased Efficiency of Sheep Production.
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Progress 01/01/02 to 12/31/02
Outputs
A breeding project is underway to examine the maternal benefits from incorporating genes of the East Friesian, a European milk breed, into the Polypay, a prolific U.S. breed. Results to date comparing purebred Polypays with 3/4 Polypay - 1/4 East Friesian ewes indicate no reduction in ewe prolificacy but little maternal benefit in growth rate of lambs being raised to weaning on pasture as either twins or triplets. Studies are underway to compare milk production and lactation response to supplementation. A separate study of genetic effects on embryonic losses is showing major influences of both maternal and embryo genotypes. Animals with blackface (primarily Suffolk) breeding are exhibiting higher loss rates following conception to multiple ovulations. Hormone profiles will be compared between ewes with repeated records of embryonic losses vs. contemporaries that have shown consistent high embryonic survival.
Impacts
Since producers are paid on total weight of lamb marketed, all sheep producers are in a position to benefit from changing their breeding programs to incorporate new genetic material beneficial to their management and marketing conditions. The combined aims of this research are to both produce more lambs and grow them to heavier weaning weights.
Publications
- Meyer, H.H. 2002. Genetic and environmental impacts on prenatal loss. Sheep Res. J. 18: (In press).
- Meyer, H.H. and J.M. Thompson. 2002. Utilization of East Friesian breeding to increase lamb production. Proc. 1999 NCR-190 Technical Committee `Increased Efficiency of Sheep Production'.
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Progress 01/01/01 to 12/31/01
Outputs
Two research projects are have been initiated to evaluate the merits of sheep breeds recently imported into the U.S. The first project compared the Dorper, a South African breed promoted as a sire of market lambs, with the Suffolk, the breed most commonly used for that purpose. When grown from weaning to slaughter in feedlot, crossbred lambs of the two sire breeds grew at similar rates but Dorper-sired carcasses were fatter with no indication of greater muscling. Comparison of the two genotypes under winter grazing conditions found the Dorper lambs to grow more slowly and again produce fatter carcasses with no greater muscling. The second project is examining maternal benefits from incorporating genes of the East Friesian (EF), a European milk breed, into the Polypay, a prolific U.S. breed. EF crosses showed increased prolificacy (2.5 vs. 2.3 lambs/ewe) and larger udders following lambing compared to Polypay controls. In the first year, no ewe genotype differences
were observed in lamb rearing ability measured under typical pasture grazing conditions. In the second year, the two genotypes will be compared when rearing twins and triplets when supplemented on pasture.
Impacts
Weight of lamb marketed per ewe is the largest single factor determining sheep operation profitability. Increasing lamb survival and weaning weights in prolific ewes is a major step toward increased profitability.
Publications
- Meyer, H.H., J.M. Thompson, and T.M. Spezzano. 2001. Survival, growth and carcass characteristics of lambs sired by Dorper and Suffolk sires. Proc. West. Sect. Amer. Soc. Anim. Sci. 52:121-122.
- Meyer, H.H., J.M. Thompson and T.M. Spezzano. 2001. Comparison of Dorpers and Suffolks as terminal sires. Ann. Rpt. WCC-039: Coordination of Sheep and Goat Research and Education Programs for the Western States.
- Meyer, H.H., J.M. Thompson and T.M. Spezzano. 2001. Comparison of Dorpers and Suffolks as terminal sires. Ann. Rpt. NCR-190: Increased Efficiency of Sheep Production
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