Journal article
Growth pattern to the end of the mating period influences the reproductive performance of Merino ewe lambs mated at 7 to 8 months of age
Small Ruminant Research, Vol.179, pp.1-6
2019
Abstract
The reproductive performance of Merino ewe lambs is highly variable and generally poor in comparison to older ewes. In this study, we determined the impacts of growth pattern to the end of the mating period and sire genetics on the reproductive performance of Merino ewe lambs. Five hundred ewe lambs with full pedigree records were managed under commercial conditions from weaning and weighed 43.5 kg at the start of the mating period with an average age of 224 days. The ewe lambs were offered a moderate or high feed allowance to achieve target growth rates of 100 or 200 g/day during a 46-day mating period. They were then recombined and scanned for pregnancy status 60 days after the mating period. At the individual animal level, a 5 kg greater live weight at the start of the mating period increased reproductive rate (foetuses per 100 ewes joined) by about 20% (P < 0.001). Regardless of their live weight at the start of the mating period, gaining an extra 100 g/day of live weight during the mating period further increased their reproductive rate by about 20% (P < 0.001). Ewe lambs from sires with higher Australian Sheep Breeding Values for fat measured post-weaning achieved a higher fertility (P < 0.05) and reproductive rate (P < 0.01) regardless of feed allowance treatment. The effects of sire fatness was significant even when the sire breeding values for live weight measured post-weaning were included in the model. The effects of managing growth pattern and sire genetics were additive, so improving the reproductive performance of Merino ewe lambs mated at 7 to 8 months of age requires improving their feed allowance and rate of live weight gain until the end of the mating period and using sires with higher breeding values for fatness.
Details
- Title
- Growth pattern to the end of the mating period influences the reproductive performance of Merino ewe lambs mated at 7 to 8 months of age
- Authors/Creators
- A. Thompson (Author/Creator) - Murdoch UniversityC. Bairstow (Author/Creator) - Murdoch UniversityM. Ferguson (Author/Creator) - Murdoch UniversityG. Kearney (Author/Creator) - 36 Payne Road, Hamilton, Vic, 3300, AustraliaC. Macleay (Author/Creator) - Department of Primary Industries and Regional DevelopmentH. Thompson (Author/Creator) - Moojepin Multi-Purpose Merinos, Nyabing Rd Katanning, WA, 6317, AustraliaB. Paganoni (Author/Creator) - Department of Primary Industries and Regional Development
- Publication Details
- Small Ruminant Research, Vol.179, pp.1-6
- Publisher
- Elsevier BV
- Identifiers
- 991005542742607891
- Copyright
- © 2019 Elsevier B.V.
- Murdoch Affiliation
- School of Veterinary and Life Sciences
- Language
- English
- Resource Type
- Journal article
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- Collaboration types
- Domestic collaboration
- International collaboration
- Citation topics
- 3 Agriculture, Environment & Ecology
- 3.51 Dairy & Animal Sciences
- 3.51.115 Livestock Reproduction
- Web Of Science research areas
- Agriculture, Dairy & Animal Science
- ESI research areas
- Plant & Animal Science