@conference {40843,
	title = {Effect of selection for early lambing on the testicular diameter of the male offspring},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {56},
	year = {1996},
	month = {Jan},
	pages = {310-313},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	abstract = {Testicular size has been linked to reproductive efficiency and changes  in testicular size could provide an early indicator for the choice of ram  lambs to be used in flocks selecting for out-of-season breeding ability. For 3  years, 20 ram lambs from each of the BV(DL)-ve (earlier lambing) and  BV(DL)+ve (later lambing) flocks at Ruakura were monitored for testicular  diameter (TD) and liveweight (LWT) from weaning until November the  following year. In 1991 and 1992, BV(DL) class and season of birth were  confounded while in 1993 both BV(DL) classes were represented in both  seasons of birth (Autumn and Spring). At the same age Autumn born BV(DL)-ve rams had larger (P<0.05) TD than  did Spring born BV(DL)+ve rams in all years. For the 1993 born lambs, the  shape of the TD growth curve was different for each BV(DL) x season of  birth sub-class (P<0.001). However, at any single age point the within sub- class variation in TD (rsd = 4.6 mm) was such that no meaningful selection  for BV(DL) could be made within rams for that season of birth. Liveweight  interacted with TD and this effect was also influenced by the season of birth. These data indicate that while TD is influenced by season of birth, the  difference in TD between ram lambs of divergent BV(DL; selection for out- of-season breeding ability) was not sufficient for TD to be a useful  parameter for early selection. },
	issn = {1176-5283},
	author = {Smith JF and Parr J and Duganzich DM}
}
