Journal article
Divergent breeding values for fatness or residual feed intake in Angus cattle. 1. Pregnancy rates of heifers differed between fat lines and were affected by weight and fat
Animal Production Science, Vol.58(1), pp.33-42
2017
Abstract
The pregnancy rate of heifers affects the efficiency and profitability of beef herds. Heifers extreme in rib fatness (Fat) or post-weaning residual feed intake (RFI) estimated breeding values (EBVs) were evaluated for their pregnancy rates at two locations in the southern agricultural regions of Australia (Struan and Vasse) as part of the Beef Cooperative Research Centre Maternal Productivity Project. Heifers divergent in Fat (High-Fat and Low-Fat) had differences in fat depth pre-joining at the 12/13th rib (4.4 mm vs 3.5 mm) and P8 rump site (6.1 mm vs 4.8 mm). This was associated with significant differences in pregnancy rates over a 9-week joining period (91.5% vs 83.0%) and an even larger difference when calculated over a 6-week joining period (77.3% vs 65.0%). Heifers divergent in RFI (Vasse only) also differed in rib fat (7.6 mm vs 6.4 mm) and P8 fat (11.0 vs 9.2 mm), but not significantly in pregnancy rates between the two RFI (High-RFI and Low-RFI) genotypes following a 9-week (92.4% vs 88.5%) or 6-week (81.2% vs 73.7%) joining period. The phenotypic analysis of the Fat and RFI heifers together indicated that weight and fat depth were the largest contributing factors to variation in pregnancy rates, and age and pre-joining weight gain were not significant. These phenotypic characteristics indicated that producers can manage heifers to particular weight and fat combinations to improve heifer conception rates. Associations of BREEDPLAN EBVs with heifer fertility showed that a shorter days-to-calving EBV had the biggest impact (P < 0.001) on heifer pregnancy rates and rib fat and scrotal size EBVs were close to significant (P < 0.10).
Details
- Title
- Divergent breeding values for fatness or residual feed intake in Angus cattle. 1. Pregnancy rates of heifers differed between fat lines and were affected by weight and fat
- Authors/Creators
- F.M. Jones (Author/Creator) - Agriculture and FoodJ.M. Accioly (Author/Creator) - Agriculture and FoodK.J. Copping (Author/Creator) - South Australian Research and Development InstituteM.P.B. Deland (Author/Creator) - South Australian Research and Development InstituteJ.F. Graham (Author/Creator) - Department of Environment, Land, Water and PlanningM.L. Hebart (Author/Creator) - The University of AdelaideR.M. Herd (Author/Creator) - University of New EnglandM. Laurence (Author/Creator) - Murdoch UniversityS.J. Lee (Author/Creator) - The University of AdelaideE.J. Speijers (Author/Creator) - Agriculture and FoodW.S. Pitchford (Author/Creator) - The University of Adelaide
- Publication Details
- Animal Production Science, Vol.58(1), pp.33-42
- Publisher
- CSIRO Publishing
- Identifiers
- 991005544458907891
- Copyright
- © 2017 CSIRO
- Murdoch Affiliation
- School of Veterinary and Life Sciences
- Language
- English
- Resource Type
- Journal article
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Source: InCites
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InCites Highlights
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- Collaboration types
- Domestic 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
- Agricultural Sciences