Hostname: page-component-cd9895bd7-mkpzs Total loading time: 0 Render date: 2024-12-28T00:59:50.308Z Has data issue: false hasContentIssue false
  • English
  • Français

Strategies for rapid rebreeding of lactating ewes in the spring

Published online by Cambridge University Press:  12 March 2014

K. J. Goff ,
D. R. Notter ,
H.-B. Vanimisetti  and
J. W. Knight
K. J. Goff
Affiliation:
Department of Animal and Poultry Sciences, Virginia Tech, Blacksburg, VA 24061, USA
D. R. Notter*
Affiliation:
Department of Animal and Poultry Sciences, Virginia Tech, Blacksburg, VA 24061, USA
H.-B. Vanimisetti
Affiliation:
Department of Animal and Poultry Sciences, Virginia Tech, Blacksburg, VA 24061, USA
J. W. Knight
Affiliation:
Department of Animal and Poultry Sciences, Virginia Tech, Blacksburg, VA 24061, USA
*
†E-mail: drnotter@vt.edu
Get access

Abstract

Rapid rebreeding of winter- and spring-lambing ewes is essential if ewes are to lamb more than once per year, but fertility of lactating ewes is often low and early weaning of lambs may be undesirable in forage-based production systems. Selection to improve fertility in spring matings has been successful and led to development of ewes with a reduced seasonal anestrus. Potential for rapid rebreeding of lactating out-of-season breeding (OOS) ewes was tested in three studies. In Experiment 1, effects of short-term lamb removal on rebreeding was evaluated over 2 years using 71 January-lambing OOS ewes. At an average of 63 days postpartum, 36 ewes had lambs removed for 72 h, and all ewes were joined with rams. Circulating progesterone levels indicated that 74% of ewes ovulated before lamb separation; 91% of ewes mated within 5 weeks of ram exposure, 85% were diagnosed as pregnant and 75% lambed. The average interval between lambings was 225 days. In contrast to results observed in cattle, none of the measured variables was affected by lamb separation (P>0.20). Experiment 2 compared rebreeding performance of 24 OOS and 23 St. Croix ewes that lambed in January and averaged 60 days postpartum at ram introduction. More OOS ewes ovulated, mated and became pregnant during the first 21 days of ram exposure (83.3%, 58.3%, and 41.7%, respectively; P<0.001) compared with St. Croix ewes (26.1%, 0%, and 0%, respectively). After 39 days of ram exposure, pregnancy rates still favored OOS ewes (66.7% v. 39.1%; P=0.06), but the percentage of ewes that lambed did not differ (P>0.20) between OOS (47.8%) and St. Croix ewes (34.8%). In the third study, 34 March-lambing OOS ewes were exposed to rams on May 3 at an average of 40 days postpartum to characterize their reproductive performance. After 39 days of ram exposure, 52.9±8.7% of the ewes had mated, and 38.2±8.5% were diagnosed as pregnant. However, only 20.6±7.0% of the ewes produced viable lambs, suggesting a high level of uterine insufficiency. Spring fertility of lactating OOS ewes in these studies was one of the highest reported in the literature and indicated that selection for fertility in spring mating would improve reproductive performance in accelerated lambing programs. However, exposure of lactating OOS ewes to rams at 30 to 50 days postpartum was associated with high prenatal lamb mortality.

Keywords

lactational anestrusram effectreproductionseasonal breedingselectionsheep
Type
Full Paper
Information
animal , Volume 8 , Issue 6 , June 2014 , pp. 968 - 974
Copyright
© The Animal Consortium 2014 

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

Al-Shorepy, SA and Notter, DR 1997. Response to selection for fertility in a fall-lambing sheep flock. Journal of Animal Science 75, 2033–2040.CrossRefGoogle Scholar
Bourke, ME 1964. A comparison of joining systems for prime lamb production. Proceedings of the Australian Society of Animal Production 5, 129–134.Google Scholar
Brown, MA and Jackson, WG 1995. Ewe productivity and subsequent preweaning lamb performance in St. Croix sheep bred at different times during the year. Journal of Animal Science 73, 1258–1263.CrossRefGoogle Scholar
Chemineau, P, Daveau, A, Cognie, Y, Aumont, G and Chesneau, D 2004. Seasonal ovulatory activity exists in tropical Creole female goats and Black Belly ewes subjected to a temperate photoperiod. BMC Physiology 4, 12.CrossRefGoogle ScholarPubMed
Cognie, Y, Hernandez-Barreto, M and Saumande, J 1975. Low fertility in nursing ewes during the non-breeding season. Annales de Biologie Animale, Biochimie, Biophysique 15, 329–343.CrossRefGoogle Scholar
De Nicolo, G, Morris, ST, Kenyon, PR and Morel, PCH 2006. Effect of weaning pre- or post-mating on performance of spring-mated ewes and their lambs in New Zealand. New Zealand Journal of Agricultural Research 49, 255–260.CrossRefGoogle Scholar
Dixon, AB, Knights, M, Winkler, JL, Marsh, DJ, Pate, JL, Wilson, ME, Dailey, RA, Seidel, G and Inskeep, EK 2007. Patterns of late embryonic and fetal mortality and association with several factors in sheep. Journal of Animal Science 85, 1274–1284.Google Scholar
Duncan, JGS and Black, WJM 1978. A twice-yearly lambing system, using Finnish Landrace×Dorset Horn ewes. Animal Production 26, 301–308.Google Scholar
El-Saied, UM, de la Fuente, LF and San Primitivo, F 2006. Lifetime traits comparison between annual and accelerated lambing systems for dairy ewes. Livestock Science 101, 180–190.CrossRefGoogle Scholar
Fogarty, NM, Dickerson, GE and Young, LD 1984. Lamb production and its components in pure breeds and composite lines. I. Seasonal and other environmental effects. Journal of Animal Science 58, 285–300.Google Scholar
Galina, MA, Morales, R, Silva, E and López, B 1996. Reproductive performance of Pelibuey and Blackbelly sheep under tropical management systems in Mexico. Small Ruminant Research 22, 31–37.Google Scholar
Geary, TW, Salverson, RR and Whittier, JC 2001a. Synchronization of ovulation using GnRH or hCG with the CO-Synch protocol in suckled beef cows. Journal of Animal Science 79, 2536–2541.Google Scholar
Geary, TW, Whittier, JC, Hallford, DM and MacNeil, MD 2001b. Calf removal improves conception rates to the Ovsynch and CO-Synch protocols. Journal of Animal Science 79, 1–4.CrossRefGoogle Scholar
Goff, KM, Knight, JW, Pelzer, KD, Akers, RM and Notter, DR 2013. Circannual changes in progesterone secretion in intact ewes, luteinizing hormone secretion in ovariectomized estradiol-implanted ewes, and prolactin secretion in three sheep breeds anticipated to differ in seasonality of reproduction. Animal Reproduction Science 138, 194–202.Google Scholar
Hafez, ESE 1952. Studies on the breeding season and reproduction in the ewe. Journal of Agricultural Science 42, 189–265.Google Scholar
Hulet, CV, Ercanbrack, SK and Knight, AD 1984. Development of the Polypay breed of sheep. Journal of Animal Science 58, 15–24.CrossRefGoogle ScholarPubMed
Hunter, GL 2010. Accelerated lambing. Part 2. Increasing the frequency of pregnancy in sheep. CAB Reviews: Perspectives in Agriculture, Veterinary Science, Nutrition and Natural Resources 5, 009, 1-24. Retrieved June 21, 2013, from http://www.cabi.org/cabreviews/?loadmodule=review&page=4051&reviewid=138205&site=167 Google Scholar
Kassem, R, Owen, JB and Fadel, I 1989. Rebreeding activity in milking Awassi ewes under semi-arid conditions. Animal Production 49, 89–93.Google Scholar
Kiser, TE, Dunlap, SE, Benyshek, LL and Mares, SE 1980. The effect of calf removal on estrous response and pregnancy rate of beef cows after Synchro-Mate B treatment. Theriogenology 13, 381–389.Google Scholar
Knights, M, Ramgattie, R, Siew, N, Singh-Knights, D and Bourne, G 2011. Effectiveness of a short-term treatment with progesterone injections on synchrony of lambing and fertility in tropical hair sheep. Animal Reproduction Science 126, 70–75.Google Scholar
Landis, RJ, Heyman, ER and Koch, GG 1978. Average partial association in three-way contingency tables: a review and discussion of alternative tests. International Statistical Reviews 46, 237–254.Google Scholar
Lewis, RM, Notter, DR, Hogue, DE and Magee, BH 1996. Ewe fertility in the STAR accelerated lambing system. Journal of Animal Science 74, 1511–1522.Google Scholar
Martemucci, G and D’Alessandro, AG 2010. Estrous and fertility responses of dairy ewes synchronized with combined short term GnRH, PGF2α and estradiol benzoate treatments. Small Ruminant Research 93, 41–47.Google Scholar
Mavrogenis, AP and Chimonides, I 1992. Reproductive and production efficiency of Chios ewes under an accelerated breeding system. Small Ruminant Research 7, 353–360.CrossRefGoogle Scholar
Minton, JE, Coppinger, TR, Spaeth, CW and Martin, LC 1991. Poor reproductive response of anestrous Suffolk ewes to ram exposure is not due to failure to secrete luteinizing hormone acutely. Journal of Animal Science 69, 3314–3320.CrossRefGoogle Scholar
Notter, DR and Copenhaver, JS 1980. Performance of Finnish Landrace crossbred ewes under accelerated lambing. I. Fertility, prolificacy and ewe productivity. Journal of Animal Science 51, 1033–1042.CrossRefGoogle Scholar
Notter, DR and Cockett, NE 2005. Opportunities for detection and use of QTL influencing seasonal reproduction in sheep: a review. Genetics Selection Evolution 37 (suppl. 1), 39–53.Google Scholar
Notter, DR, Smith, JK and Akers, RM 2011. Patterns of estrous cycles, estrous behavior, and circulating prolactin in spring and summer in ewes selected for autumn lambing and exposed to ambient or long-day photoperiods. Animal Reproduction Science 129, 30–36.CrossRefGoogle ScholarPubMed
Nugent, RA III and Notter, DR 1990. Effects of cohabitation with white-faced ewes on estrous activity of Hampshire and Suffolk ewes exposed to rams in June. Journal of Animal Science 68, 1513–1519.CrossRefGoogle ScholarPubMed
Nugent, RA III, Notter, DR and McClure, WH 1988. Effects of ram pre-exposure and ram breed on fertility of ewes in summer breeding. Journal of Animal Science 66, 1622–1626.Google Scholar
Oldham, CM and Martin, GB 1978. Stimulation of seasonally anovular Merino ewes and rams II: Premature regression of ram-induced corpora lutea. Animal Reproduction Science 1, 291–295.CrossRefGoogle Scholar
Oldham, CM, Pearce, DT and Gray, SJ 1985. Progesterone priming and age of ewe affect the life-span of corpora lutea induced in seasonally anovulatory Merino ewes by the “ram effect”. Journal of Reproduction and Fertility 75, 29–33.Google Scholar
Parker, CF, McClure, KE and Herd, RP 1991. Hair sheep potential for specific environmental conditions and production systems in North America. In Proceedings of the Hair Sheep Research Symposium (ed. S Wildeus), pp. 155–172. University of the Virgin Islands Agricultural Experiment Station, St. Croix, Virgin Islands, USA.Google Scholar
Pope, WF, McClure, KE, Hogue, DE and Day, ML 1989. Effect of season and lactation on postpartum fertility of Polypay, Dorset, St. Croix, and Targhee ewes. Journal of Animal Science 67, 1167–1174.Google Scholar
Quirke, JF, Stabenfeldt, GH and Bradford, GE 1988. Year and season effects on oestrus and ovarian activity in ewes of different breeds and crosses. Animal Reproduction Science 16, 39–52.CrossRefGoogle Scholar
Restall, BJ, Kearins, RD, Herdegen, J and Carberry, P 1978. The induction of reproductive activity in lactating ewes. Australian Journal of Agricultural Research 29, 181–187.Google Scholar
Smith, MC 2006. Veterinary experiences with the Cornell STAR system of accelerated lambing. Small Ruminant Research 62, 125–128.Google Scholar
Stagg, K, Spicer, LJ, Sreenan, JM, Roche, JF and Diskin, MG 1998. Effect of calf isolation on follicular wave dynamics, gonadotropin and metabolic hormone changes, and interval to first ovulation in beef cows fed either of two energy levels postpartum. Biology of Reproduction 59, 777–783.Google Scholar
Tervit, HR and Peterson, AJ 1978. Testosterone levels in Dorset and Romney rams and the effectiveness of these breeds in stimulating early onset of estrus in Romney ewes. Theriogenology 9, 271–278.Google Scholar
Vincent, JN, McQuown, EC and Notter, DR 2000. Duration of the seasonal anestrus in sheep selected for fertility in fall lambing. Journal of Animal Science 78, 1149–1154.Google Scholar
Whiteman, JV, Zollinger, WA, Thrift, FA and Gould, MB 1972. Postpartum mating performance of ewes involved in a twice-yearly lambing program. Journal of Animal Science 35, 836–842.Google Scholar
Wildeus, S 1997. Hair sheep genetic resources and their contribution to diversified small ruminant production in the United States. Journal of Animal Science 75, 630–640.Google Scholar
Yelich, JV, Holland, MD, Schutz, DN and Odde, KG 1995. Synchronization of estrus in suckled postpartum beef cows with melengestrol acetate, 48-hour calf removal and PGF2 . Theriogenology 43, 401–410.Google Scholar