Genetic aspects of ewe longevity and fertility traits in Lleyn and Dorset sheep

摘要

Improving ewe longevity, or productive lifespan in sheep, is of high economic importance due to the potential to reduce culling rates and female replacement costs.Material and methods Data from commercial Dorset and Lleyn flocks, recording as part ofthe Signet Sheepbreeder Programme, were used for this study. The three traits studied were: Longevity (LONG), defined as the age (in years) at the last recorded lambing event; Age at first lambing (AFL), defined as the age of the ewe (in years) at her first recorded lambing event; Lambing interval (LI), defined as the number of days between the ewe’s first and second lambing event. Ewes born between 1980 and 2000 were used for the LONG analyses, to allow them to achieve their full lifetime in the flockprior to data analysis, whereas data from 1980-2011 were used for AFL and LI. The number of data records per trait, per breed, for LONG, AFL and LI were 14,047, 20,816 and 14,648 for Dorsets (n=60 flocks) and 13,652, 30,597 and 18,391 for Lleyns (n=129flocks) respectively. The pedigree files used contained sire and dam information for 236,333 and 366,509 Dorset and Lleyn animals respectively.