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Litter size at lambing influences genetic evaluation of maternal rearing ability
- Source :
- Animal Production Science. 58:791
- Publication Year :
- 2018
- Publisher :
- CSIRO Publishing, 2018.
-
Abstract
- The genetic parameters for maternal rearing-ability of ewes were investigated by ignoring or defining the rearing ability trait separately by litter-size class (singles versus multiples) using multi-generational data from three, fully pedigreed Merino flocks differing in prolificacy, production level and environment. Genetic correlations (ra) between litter size (LSIZE) and the percentage of lambs surviving (PLSURV) were more negative with an increasing mean flock litter size (ra: –0.21 ± 0.17 to –0.73 ± 0.08), while the corresponding range in phenotypic correlations (rp) was substantially lower (rp: –0.15 ± 0.01 to –0.33 ± 0.01). Rearing-ability traits defined separately by litter-size class were highly correlated (ra: 0.49 ± 0.19 to 0.64 ± 0.38), but not genetically identical traits in the most prolific flock. Defining rearing-ability traits separately by litter-size class reduced the antagonistic genetic correlations between LSIZE and PLSURV to between –0.39 ± 0.14 and 0.14 ± 0.28, through accommodating the change in mean and variance of PLSURV with LSIZE. Similarly, linear transformation (TSURV) of PLSURV within each litter size to a common mean and variance reduced the antagonistic trend in genetic correlations between LSIZE and TSURV to range between –0.05 ± 0.17 and –0.43 ± 0.13. Since genetic correlations are low to moderate between TSURV and LSIZE, it is possible to select for improvements in both the number of lambs born and lamb survival simultaneously. Defining rearing-ability traits separately by litter-size class and the role of transformation will be investigated further for improving the accuracy of genetic evaluation for rearing ability across a range of flocks, breeds and environmental conditions using more extensive industry data.
- Subjects :
- 0301 basic medicine
Litter (animal)
Ecology
media_common.quotation_subject
Domestic sheep reproduction
0402 animal and dairy science
04 agricultural and veterinary sciences
Heritability
Biology
040201 dairy & animal science
Correlation
03 medical and health sciences
030104 developmental biology
Animal science
Common mean
Trait
Animal Science and Zoology
Flock
Reproduction
Food Science
media_common
Subjects
Details
- ISSN :
- 18360939
- Volume :
- 58
- Database :
- OpenAIRE
- Journal :
- Animal Production Science
- Accession number :
- edsair.doi...........52f7c3502e6a7e82748b8c7503b11dfb
- Full Text :
- https://doi.org/10.1071/an16422