Sheep research offers alternatives to improve production
AuthorsEdward O. Price
G. Eric Bradford
Authors AffiliationsE.O. Price is Professor, Department of Animal Science, College of Agricultural and Environmental Sciences, UC Davis; G.E. Bradford is Professor Emeritus, Department of Animal Science, College of Agricultural and Environmental Sciences, UC Davis.
Hilgardia 55(6):19-25. DOI:10.3733/ca.v055n06p19. November 2001.
Scientists working at the UC Hopland Research and Extension Center (HREC) have made important contributions to the sheep industry in breeding and genetics, and in the understanding of animal behavior. A long-term experiment involving HREC was initiated in 1960 to evaluate the effects of selection environment on sheep performance under range conditions. Selectrion of the UC Davis flock, representing the favorable conditions typical of purebred flocks where most breeding rams are raised, resulted in more within-flock improvement in weaning weight than selection under range conditions at Hopland. However, when the UC Davis- and Hopland-selected lines were compared under range conditions at HREC, the two were equal in weaning weight, and the Hopland line was superior in reproduction and total productivity. We concluded that selection should take place in the environment of use. In the late 1970s, investigations were initiated to develop cost-efficient techniques for fostering lambs to unrelated ewes; an effective new method was developed using stockinette jackets and neatsfoot oil to transfer odors. Likewise, research on sexual behavior has resulted in several relatively simple behavioral tests that can be used to determine the performance of rams.
Bench CJ, Price EO, Dally MR, et al. Artificial selection of rams for sexual performance and its effect on the sexual behavior and fecundity of male and female progeny. Appl Anim Behav Sci. 2001. 72:41-50. https://doi.org/10.1016/S0168-1591(00)00191-X PubMed PMID: 11259825
Bradford GE, Sakul H, Dally MR. Selection for litter size or weaning weight in range sheep: II Correlated responses and effect on productivity. Sheep Goat Res J. 1999. 15:134-42.
Bradford GE, Torell DT, Spurlock GM, Weir WC. Performance and variability of offspring of crossbred and purebred rams. J Anim Sci. 1963. 22:617-23.
Bradford GE, Weir WC, Torell DT. Growth rate, carcass grades and net returns of Suffolk- and Southdown-sired lambs under range conditions. J Anim Sci. 1960. 19:493-501.
Erhard HW, Price EO, Dally MR. Competitive ability of rams selected for high and low levels of sexual performance. Anim Sci. 1998. 66:403-8.
Estep DQ, Price EO, Wallach SJ, et al. Social preferences of domestic ewes for rams (Ovis aries). Appl Anim Behav Sci. 1989. 24:287-300. https://doi.org/10.1016/0168-1591(89)90057-9
Lasslo LL, Bradford GE, Torell DT, et al. a. Selection for weaning weight in Targhee sheep in two environments. I. Direct response. J Anim Sci. 1985. 61:376-86. PubMed PMID: 4044436
Lasslo LL, Bradford GE, Torell DT, et al. b. Selection for weaning weight in Targhee sheep in two environments. II. Correlated effects. J Anim Sci. 1985. 61:387-409. PubMed PMID: 4044437
Martin NL, Price EO, Wallach SJ, Dally MR. Fostering lambs by odor transfer: The add-on experiment. J Anim Sci. 1987. 64:1378-83. PubMed PMID: 3583944
Price EO, Borgwardt R, Blackshaw JK, et al. Effect of early experience on the sexual performance of yearling rams. Appl Anim Behav Sci. 1994. 42:41-8. https://doi.org/10.1016/0168-1591(94)90005-1
Price EO, Borgwardt R, Dally MR, et al. Repeated matings with individual ewes by rams differing in sexual performance. J Anim Sci. 1996. 74:542-4. PubMed PMID: 8707708
Price EO, Borgwardt R, Dally MR. Effect of early fenceline exposure to estrous ewes on the sexual performance of yearling rams. Appl Anim Behav Sci. 1999. 64:241-7. https://doi.org/10.1016/S0168-1591(99)00040-4
Price EO, Dally MR, Erhard HW, et al. Manipulating odor cues facilitates add-on fostering in sheep. J Anim Sci. 1998. 76:961-4. PubMed PMID: 9581917
Price EO, Dunbar JM, Dally MR. Behavior of ewes and lambs subjected to restraint fostering. J Anim Sci. 1984. 58:1084-9. PubMed PMID: 6735940
Price EO, Dunn GC, Talbot JA, et al. Fostering lambs by odor transfer: The substitution experiment. J Anim Sci. 1984. 59:301-7. PubMed PMID: 6480529
Price EO, Estep DQ, Wallach SJ, et al. Sexual performance of rams as determined by maturation and sexual experience. J Anim Sci. 1991. 69:1047-52. PubMed PMID: 2061236
Sakul H, Bradford GE, BonDurant RH, et al. Cryopreservation of embryos as a means of germ plasm conservation in sheep. Theriogenol. 1993. 39:401-9. https://doi.org/10.1016/0093-691X(93)90383-G
Sakul H, Bradford GE, Dally MR. Selection for litter size or weaning weight in range sheep: I Selection practiced and direct response. Sheep Goat Res J. 1999. 15:122-33.
Sakul H, Dally MR, Bradford GE. Evaluation of Australian merino and U.S. sheep breeds for feed and carcass traits. J Anim Sci. 1993. 71:363-8. PubMed PMID: 8440655
Tomlinson KA, Price EO, Torell DT. Responses of tranquilized postpartum ewes to alien lambs. Appl Anim Ethol. 1982. 8:109-17. https://doi.org/10.1016/0304-3762(82)90136-5
Also in this issue:Activity levels of genetically manipulated and wild strains of Metaseiulus occidentalis (Nesbitt) (Acarina: Phytoseiidae) compared as a method to assay quality
UC Research and Extension Centers: Statewide system provides local answers to local needs
Hopland celebrates 50 years of rangeland research
European grapes tested in North Coast vineyards
Research on animal-borne parasites and pathogens helps prevent human disease
Callipyge meat a tough sell
Is there a sire-dam interaction in sperm fertilizing potential?
Sheep-killing coyotes a continuing dilemma for ranchers
Targeting alphas can make coyote control more effective and socially acceptable
Agroforestry is promising for previously cleared hardwood rangelands
Monitoring shows vegetation change at multiple scales
Carefully timed burning can control barb goatgrass
Animals and fungi can affect goatgrass establishment
Plant species provide vital ecosystem functions for sustainable agriculture, rangeland management and restoration
Australian varieties improve pasture in long-term annual legume trials
Watershed research examines rangeland management effects on water quality