Progress 09/15/06 to 08/31/09
Outputs
OUTPUTS: Results of this study have been shared with with producers and scientists attending several international conferences of the Senepol breed in Panama, Venezuela, Colombia and St. Croix, U.S. Virgin Islands over the years of this study. Both the effects of the Slick hair gene in upgraded Holstein cattle and use of cattle with the Slick hair gene in crossbreeding systems for both beef and dairy production have been discussed. PARTICIPANTS: T.A. Olson, University of Florida (PI) was responsible for the entire project and all collaborative efforts with other PIs and the USDA-ARS (Brooksville). Also responsible for the selection efforts to utilize elite Holstein sires in matings to slick-haired Holstein cows to improve the additive genetic merit of slick-haired Holsteins. J. Pantoja, University of Puerto Rico (Co-PI) was responsible for the dissemination of semen from slick-haired Holstein bulls to private herds within Puerto Rico and obtaining data from the slick- and normal-haired progeny resulting from use of this semen. E. Alava, University of Florida M.S. graduate student whose training was supported by funds from this TSTAR project. He was responsible for collecting the feed intake data on the slick- and normal-haired lactating Holstein cows and evaluation of potential differences in digestive efficiency as well as measures of adaptation including rectal and vaginal temperatures, and respiration and sweating rates. TARGET AUDIENCES: Producers of beef, dairy and dual-purpose cattle in warm countries (tropical and subtropical) should find the use of cattle possessing the Slick hair gene useful to improve productivity of unadapted (Bos taurus) cattle that are under sufficient heat stress. Through the use of referreed and other publications, as well as conference presentations and proceedings, this information is being made available to such producers in the Americas and Australia. PROJECT MODIFICATIONS: Not relevant to this project.
Impacts
During the course of this study we have identified that lactating Holstein cows (upgraded to 87.5% or more Holstein that possess the Slick hair gene have the ability to maintain lower rectal temperatures and respiration rates, as well as lower vaginal temperatures while under moderate to acute levels of heat stress. Lactating cows with the Slick hair gene did not, however, consume more feed nor did they show more efficient digestion of consumed feed than did contemporaries without the Slick hair gene during the late summer/early fall near Gainesville, Florida. While many of the cows in this project, both at the University of Florida and at private dairies that were sired by unproven, percentage Holstein cows did not prove to have acceptable levels of milk yield, those cows with the Slick hair gene but sired by proven registered Holstein sires were among the best cows in these herds, proving that additive genetic merit for milk yield and not some detrimental effect of the Slick hair gene was responsible for the lower production of some slick-haired Holstein cows. No evidence has been shown to date that the slick-haired Holstein cows were more fertile than their normal-haired contemporaries. It seems that the management under which our cows were evaluated, with shade, sprinklers and fans limited the ability of improved heat tolerance of the slick-haired Holstein cows to result in greater productivity or superior fertility and disease resistence. Another impact of this study was to be able to determine the location of the Slick hair gene on bovine chromosome 20 in the region near where the prolactin receptor gene is located. A SNP marker system has been utilized in an effort to identify Senepol and Holstein cattle that are descended from Senepol cattle that are homozygous for the dominantly inherited Slick hair gene.
Publications
- Riley, D.G., C.C. Chase, Jr., S.W. Coleman, and T.A. Olson. 2009. Breed effects and heterosis for rectal temperature and coat score in Brahman, Angus, and Romosinuano pure and crossbred cows and calves. J. Anim. Sci. Vol. 87, E-Suppl. 3: 1.
- Bubolz, J. W., S. Tao, B.C. do Amaral, M.J. Hayen, T.A. Olson, and G.E. Dahl. 2009. Heat stress does not alter immune status of Holstein calves but slick genotype confers reduced immune function. J. Anim. Sci. Vol. 878, E-Suppl. 2/J. Dairy Sci. Vol. 92, E-Suppl. 1: 512.
- Chase, C.C., Jr., L.J. Waters, J.R. Davis, D.G. Riley, S.W. Coleman, J.A. Carroll, and T.A. Olson. 2009. Effect of shade on summer body temperature and respiration rate of Angus, Brahman, and Romosinuano heifers. J. Anim. Sci. Vol. 87, E-Suppl. 3: 1.
- Coleman, S.W., D.G. Riley, C.C. Chase, Jr., M.F. Miller, J.C. Brooks, D.D. Johnson, W.A. Phillips, and T.A. Olson. 2009. Carcass traits of tropically adapted cattle when evaluated at different endpoints. J. Anim. Sci. Vol. 878, E-Suppl. 2/J. Dairy Sci. Vol. 92, E-Suppl. 1: 367.
|
Progress 09/15/07 to 09/14/08
Outputs
OUTPUTS: Cooperators in Puerto Rico where small numbers of slick-haired Holstein cattle have existed for many years, apparently being the result of upgrading of slick-haired Criollo stock to Holsteins over a number of generations, provided a large quantity (over 600 straws) of semen from a slick-haired Holstein bull born in Florida. Use of semen from this heterozygous bull will provide for the increase in the gene frequency of the Slick hair gene in the Holstein population of Puerto Rico. Such an increase should result in increased heat tolerance and related productivity traits. Small quantities of semen (40 units per bull) were obtained from Puerto Rican slick-haired Holstein bulls that were sired by elite Holstein sires ("Oman" and "DieHard") that are unrelated to the slick-haired Holstein population present in Florida which descends presently from limited numbers of Senepol X Holstein crosses. This infusion of germ plasm should help to minimize potential increases in level of inbreeding within this population. PARTICIPANTS: Dr. Serdal Dikmen of the the University of Uludog, Faculty of Veterinary Medicine, Department of Animal Science, Bursa, Turkey was the lead investigator on an experiment investigating the degree of heat tolerance of lactating slick- vs normal-haired lactating Holstein cows while working as a post-doctoral fellow in the Department of Animal Sciences of the University of Florida. TARGET AUDIENCES: Target audiences would include dairymen in areas of the world where cattle undergo heat stress conditions and animal scientists with interests in heat stress. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
The increased heat tolerance of slick-haired, lactating Holstein cows relative to that of normal-haired contemporaries was demonstrated under both an indoor environment with fans and evaporative cooling and under an outdoor environment with shade cloth but no fans or evaporative cooling. Cows in the outdoor environment were under greater heat stress which was evidenced by higher vaginal and surface temperatures, respiration rates and sweating rates than cows under the indoor environment. In both environments slick-haired cows had lower vaginal temperatures (0.6 degrees C outdoors)and respiration rates and higher sweating rates in unclipped areas of skin. The slick-haired Holsteins were also frequently observed to be eating at the same time that the normal-haired animals were exnibiting obvious signs of heat stress and not eating under the outdoor, more stressful environment. These data indicate that slick-haired Holsteins are more resistent to heat stress, at least in part due to increased sweating rate, and thus, should be especially useful to the dairy industry under more extensive systems of management where alleviation of heat stress via fans, misting, etc. is not feasible.
Publications
- Dikman, S., Alava, E., Pontes, E., Fear, J.M., Dikmen, B.Y., Olson, T.A., and Hansen, P.J. 2008. Differences in Thermoregulatory Ability Between Slick-Haired and Wild-Type Lactating Holstein Cows in Response to Acute Heat Stress. J. Dairy Sci. 91:3395-3402.
|
Progress 09/15/06 to 09/14/07
Outputs
OUTPUTS: During the past year, several new studies have been conducted on Slick-haired Holstein cows and normal-haired contempories some of which were siblings of the slick-haired cows. At the Dairy Research Unit near Gainesville, FL, ten slick and ten normal-haired Holsteins were evaluated for their response to acute heat stress on two ocasions in August. Continuous measurement of vaginal temperatures were obtained along with rectal temperatures, respiration rates, and sweating rates which were measured every two hours. In addition, a feed intake study was conducted comparing slick- and normal-haired Holsteins over a six-week period of time beginning in late August. During this time, rectal temperatures, respiration rates and sweating rate were measured AM and PM on a weekly basis. Semen from 12 Senepol bulls with divergent pedigrees was sent to the molecular genetics group at the US MARC in the ongoing effort to identify an accurate DNA marker for the Slick hair gene. In Puerto
Rico and in Florida, production and reproduction data on slick-haired Holsteins continues to be collected. In Puerto Rico, semen from three slick-haired Holstein bulls unrelated to the Senepol-derived slick-haired Holsteins in Florida was obtained and some was distributed for use in Puerto Rican herds. Also, 600 units of semen from a Florida-born, slick-haired Holstein bull with daughters now milking in both Florida and Puerto Rico was sent to Puerto Rico for use in herds there.
PARTICIPANTS: A number of individuals worked on the project during this past year. These included Eduardo Alava, a M.S. student at the University of Florida, Department of Animal Sciences; Dr. Serdal Dikmen, a post-doctoral visiting professor from the Faculty of Veterinary Medicine of the University of Uludag in Bursa, Turkey. Dr. Peter Hansen of the Department of Animal Sciences here at the University of Florida also collaborated in a study of the effects of acute heat stress on lactating slick- and normal-haired Holsteins. Also, collaboration with the USDA continued including efforts by Dr. C.C. Chase, Jr. at the Subtropical Agricultural Research Station in Brooksville, Florida and Dr. Mike Heaton of the molecular genetics group of the US Meat Animal Research Center who is responsible for efforts to sequence the Slick hair gene and to identify a commercially useful SNP marker for it.
TARGET AUDIENCES: Target audiences will include dairy producers in the sub-tropical regions of the continental U.S. as well as throughout the Caribbean basin. Additionally, producers of milk throughout the sub-tropical and tropical areas of the world will likely benefit from the knowledge of a gene which should increase productivity of their cattle through the lessening of heat stress. Information regarding the effects of the gene had been and will be disseminated through presentations to cattle producers in the U.S. and throughout the tropical world as well as e-mail interactions with individuals who become aware of the effects of the Slick hair gene through the web and other sources.
Impacts
During this past year, our group identified that the Slick hair gene was located on Bovine Chromosome 20. On Chromosome 20 it is located between markers DIK4835 and DIK2930. While there are more than 20 candidate genes in this range, one that is of most interest is the prolactin receptor gene which is involved in hair cycling and has been found in the skin tissues of a diverse range of species. While further studies to sequence the Slick hair gene and to identify a useful commercial SNP marker are necessary, once such a marker is identified it will be very useful to Senepol breeders in the U.S. and breeders of Senepol and other slick-haired breeds throughout the world to identify bulls that are homozygous slick. The use of only homozygous bulls will avoid the production of long-haired and thus non-heat tolerant calves which can be of considerable importance in tropical areas of the world. Heat stress studies conducted during the past year confirmed again, this time
with lactating cows, that slick-haired cows under heat stress maintained a highly significant advantage in internal temperatures (about 0.5 degrees C lower). While we have not yet shown that this greater heat tolerance of slick-haired cows results in the slick-haired cows producing more milk more efficiently and are more fertile under U.S. conditions, it seems that it should.
Publications
- Chase, C. C., Jr., Mariasegaram, M., Chaparro, J. X., Olson, T. A. and Niedz, R. P. 2007. A microsatellite based test for slick hair phenotype in Senepol-derived cattle. Plant & Animal Genome XV, Final Abstracts Guide, p. 238.
- Brenneman, R.A., Chase, C.C., Jr., Olson, T.A., Riley, D.G., Coleman, S.W. 2007. Genetic diversity among Angus, American Brahman, Senepol and Romosinuano cattle breeds. Animal Genetics, 38:50-53.
- Mariasegaram, M., Chase, C.C., Jr., Chaparro, J.X., Olson, T.A., Brenneman, R.A., Niedz, R.P. 2007. The slick hair coat locus maps to chromosome 20 in Senepol-derived cattle. Animal Genetics, 38:54-59.
|
|