The mating behaviour of rams in a pedigree pen-mating system in relation to breed and fertility

Abstract

SUMMARYThree mature rams in each of four naturalized breeds (Romney, Border Leicester, Cheviot and Dorset Down) and two or three 15-mo-old rams in each of four recently imported ‘exotic’ breeds (Finnish Landrace, East Friesian, German Whiteheaded Mutton and Oxford Down) were mated to between 14 and 32 Romney ewes in a pedigree pen-mating system at Mana Island, New Zealand. Two or three 60-min observations of mating behaviour were made on each ram.There were no significant differences in mating behaviour scores between groups of breeds, but the mature rams of the naturalized breeds were more fertile than the young rams of the exotic breeds (76% and 57% ewes not returning to first mating respectively). Within the young exotic breed group there were significant differences between breeds in number of serves per test, interval to first mount and fertility. Fertility was negatively correlated with time to first mount.