Summary Lamb survival significantly impacts the productivity of the Australian sheep industry, with twin and multiple-born lambs suffering greater mortality rates than single-born lambs. Using data from the Sheep CRC Information Nucleus and MLA Resource Flock, genetic parameters for lamb survival to weaning and birth weight across different birth types were estimated. The additive genetic and maternal variances (maternal genetic and permanent environmental components) for survival to weaning were significantly higher for twin and multiple born lambs than for single born lambs. The direct heritability for survival to weaning was also higher in twin-born (0.06) than in single lambs (0.04) but not for multiples (0.04). Birthweight was weakly negatively correlated genetically to survival in single born lambs (-0.10) but positively correlated for twins (0.20), and multiples (0.29). The results of this study demonstrate that the genetic relationship between birthweight and survival is different across different types of birth, therefore selecting for overall birthweight to improve lamb survival will not be beneficial for survival across different birth types. Splitting lamb survival for type of birth may be more beneficial but challenging to implement in commercial breeding programs. Keywords: lamb survival, birth weight, genetic evaluation
Proceedings of the World Congress on Genetics Applied to Livestock Production, Volume Electronic Poster Session - Species - Ovine, , 703, 2018
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