DOES THE GENETICS OF LAMB SURVIVAL DIFFER BETWEEN SINGLE AND TWIN BORN MERINO LAMBS?

Abstract Text: Data from 2 Merino genetic resource flocks describing the survival of 12,249 single and 15,018 twin born lambs in NSW were analysed to quantify differences between the 2 birth types in genetic parameters for lamb survival to 1, 7, 30 and 110 d. Little to no differences in the additive genetic variance were evident, though larger differences, favouring twin born lambs, in the maternal permanent environment component and smaller differences for the direct maternal component were apparent. The repeatability of ewe rearing ability was higher for twin bearing ewes suggesting that retaining ewes that consistently rear twins in the breeding flock would produce greater current generation gains in lamb survival than selecting ewes that consistently rear a single lamb. 

Keywords:

Merino sheep

lamb survival

genetics