Genetic Analysis of Lamb Survival in a Crossbred Population

Abstract Text: Survival of crossbred lambs during three time periods were analyzed: until one d of age (n = 7933), from 2 to 30 (n = 5370), and from 2 to 60 (n = 5216) d of age. Mortality, sex, age of the dam, birth type, month and year of birth, and breed group were recorded, and retained heterosis was calculated for all animals. Breed groups were: meat breeds, maternal breeds, East Friesian, and Lacaune. In general, there was increased survival for lambs with higher retained individual heterosis and lambs of meat and maternal breeds compared to the Lacaune breed. There was a higher mortality for females until one day of age, but males had higher mortality at the other periods. Until one d of age, triplets had a lower survival than singles, and lambs from 1-yr-old dams had lower survival than lambs from 2-yr-old dams. 

Keywords: heterosis

lamb

survival