Analysis of weaner survival in Australian Merino

Abstract

Weaner mortality is a significant animal welfare issue and can have a large negative impact on the productivity of a sheep flock in both the long- and short-term. High weaner mortality reduces the number of potential replacements available for selection into the breeding flock, thus reducing the selection intensity and potential rate of genetic improvement (Hatcher et al. 2008). <br/> The following report covers the genetic analysis of weaner survival in Merino lambs. Weaner mortality or survival was defined as the survival rate of the Merino weaner from weaning till its first opportunity to present a post-weaning record or yearling record. The genetic analysis was based on the survival records of Merino weaners from 18 commercial ram breeders and research flocks. <br/> Weaner survival data was provided in the file “Merino weaner survival database 170815.xlsx” with the Sheep Genetics database used to source pedigree information, production trait records and capture animals missing from the original data file. <br/> The objective of the study was to provide a genetic analysis of weaner survival in Merino sheep. Thus this entailed calculating the genetic variation and the heritability of weaner survival in Merino sheep before estimating the phenotypic and genetic correlations between the weaner survival and key production traits associated with Merino production.