Short term, repeated exposure to rams during the transition into the breeding season improves the synchrony of mating in the breeding season. 2008

P A R Hawken, and A C O Evans, and A P Beard
School of Agriculture, Food and Rural Development, Newcastle University, Newcastle upon Tyne, NE1 7RU, United Kingdom. phawken@animals.uwa.edu.au

The ram effect is widely used in Mediterranean breeds of sheep but its use in temperate genotypes is restricted by breed seasonality. However, ewes from these highly seasonal genotypes are sensitive to stimulation by rams close to the onset of the natural breeding season. In this study we developed a pre-mating protocol of repeated, short-term exposure to rams (fence-line contact or vasectomised rams) beginning during late anoestrus and continuing into the breeding season. We hypothesised that this pre-mating protocol would synchronise the distribution of mating of North of England Mule ewes during the breeding season above that observed in ewes isolated from rams prior to mating. Ram-exposed ewes were given contact with rams (Experiment 1: fence-line; FR, n=94 and Experiment 2: vasectomised rams; VR; n=103) for 24h on Days 0 (10 September), 17 and 34 of the experiment. Control ewes (Experiment 1; FC, n=98 and Experiment 2; VC; n=106) remained isolated from rams prior to mating. In Experiment 2, a subset of VR (n=35) and VC ewes (n=35) were blood sampled twice weekly to monitor their pre-mating progesterone profiles. At mating, harnessed entire rams were introduced, 17 or 16 days after the last ram exposure (Experiments 1 and 2) and raddle marks were recorded daily. The median time from ram introduction to mating was reduced in ewes given both fence-line and vasectomised ram contact (P<0.001), leading to a more compact distribution of mating and lambing (At least P<0.01). In the blood sampled VR ewes, there was a progressive decline in the number of days from ram exposure to the onset of dioestrus (at least P<0.05). This observation indicates that the cycles in VR ewes became increasingly synchronised over the pre-mating period, a pattern not evident in VC ewes. In conclusion, repeated, short-term exposure of ewes to rams during the transition into the breeding season is an effective method of synchronising the distribution of mating during the breeding season.

UI MeSH Term Description Entries
D008297 Male Males
D010507 Periodicity The tendency of a phenomenon to recur at regular intervals; in biological systems, the recurrence of certain activities (including hormonal, cellular, neural) may be annual, seasonal, monthly, daily, or more frequently (ultradian). Cyclicity,Rhythmicity,Biological Rhythms,Bioperiodicity,Biorhythms,Biological Rhythm,Bioperiodicities,Biorhythm,Cyclicities,Periodicities,Rhythm, Biological,Rhythmicities,Rhythms, Biological
D011247 Pregnancy The status during which female mammals carry their developing young (EMBRYOS or FETUSES) in utero before birth, beginning from FERTILIZATION to BIRTH. Gestation,Pregnancies
D001947 Breeding The production of offspring by selective mating or HYBRIDIZATION, GENETIC in animals or plants. Breedings
D004973 Estrus Synchronization Occurrence or induction of ESTRUS in all of the females in a group at the same time, applies only to non-primate mammals with ESTROUS CYCLE. Estrus Synchronizations,Synchronization, Estrus,Synchronizations, Estrus
D005260 Female Females
D006799 Housing, Animal The physical environment in which animals are maintained. Animal Housing
D000780 Anestrus A state of sexual inactivity in female animals exhibiting no ESTROUS CYCLE. Causes of anestrus include pregnancy, presence of offspring, season, stress, and pathology.
D000818 Animals Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA. Animal,Metazoa,Animalia
D000822 Animal Husbandry The science of breeding, feeding and care of domestic animals; includes housing and nutrition. Animal Husbandries,Husbandries, Animal,Husbandry, Animal

Related Publications

P A R Hawken, and A C O Evans, and A P Beard
November 2021, Reproduction in domestic animals = Zuchthygiene,
P A R Hawken, and A C O Evans, and A P Beard
May 1988, Equine veterinary journal,
P A R Hawken, and A C O Evans, and A P Beard
October 1999, Animal reproduction science,
P A R Hawken, and A C O Evans, and A P Beard
September 1975, Veterinariia,
P A R Hawken, and A C O Evans, and A P Beard
March 1987, Journal of reproduction and fertility,
P A R Hawken, and A C O Evans, and A P Beard
August 2021, Animals : an open access journal from MDPI,
Copied contents to your clipboard!