Factors affecting survival in young alpacas (Lama pacos).

Factors affecting survival of young from birth to weaning (7 mo) in alpacas (Lama pacos) were evaluated in data collected at the Estacion Experimental de Camelidos Sudamericanos La Raya in the Altiplano region of Peru. Age of dam effects on survival rate were curvilinear; survival rate increased from approximately 78% for offspring of 3-yr-old dams to about 91% for those from 9- to 11-yr-old dams, then declined to about 85% for 15-yr-old dams. Weight of dam measured 2 mo prior to parturition was associated negatively with survival of the young (b = -.7%/kg). Alpaca born early in the season of birth had a higher survival rate than those born late; the regression of survival on birth date was -.2%/d. Survival rates were curvilinearly related with birth weight and were highest at weights of 9 to 11 kg (90%) and lowest at weights of 4 to 5 kg (20% to 40%). The estimated heritabilities of survival and birth weight were .10 +/- .17 and .34 +/- .23, weight was -.18 +/- .82; the corresponding environmental and phenotypic correlations were positive (.37 and .26, respectively).