Abstract

Longevity is a trait of economic importance in dairy goat farming. Actual longevity (AL) is defined as the number of days from birth to when the animal leaves the herd, whereas functional longevity (FL) is defined as AL adjusted for first lactation energycorrected milk yield (ECMY). This study reports the heritability (h2) for AL and FL in New Zealand dairy goats. Records of longevity from 12,108 does born between 1993 and 2011 were analysed with a model that included the fixed effects of herdyear (does born in the same herd and year) and covariates for the proportion of Alpine, Nubian, Toggenburg and heterosis, and the random effect of animal. The model for FL was the same as AL, but included ECMY as a covariate. Average AL was 1,891 (SD=832) days. Estimates of h2 were 0.07 for AL and FL. The estimated regression coefficient for ECMY on AL was 0.56 days/ litre. There were significant differences in longevity among herds, indicating that management and feeding are important factors affecting longevity. Further research is required to estimate genetic correlations with economically important traits.

MR, Scholtens, N Lopez-villalobos, DJ Garrick, and HT Blair

New Zealand Journal of Animal Science and Production, Volume 78, Lincoln, 11-15, 2018