Abstract

Dairy heifers should reach industry liveweight targets that are set to ensure heifers achieve good reproductive performance and milk production. The aim of this study was to determine if more dairy heifers born between the 2011-12 and 2014-15 dairy seasons (current) in New Zealand are achieving liveweight targets since a study on heifers born between the 2006-07 and 2010-11 dairy seasons (historic). In all age groups the mean live weight of current heifers was heavier than that of historic heifers. There were also a greater percentage of the current heifers at or above their target live weight compared with the historic heifers (P<0.001), suggesting that the rearing of dairy heifers has improved. The greatest improvement was seen at 15 months of age (mating) when 25% of historic heifers were at or above target compared with 56% of current heifers. Despite the improvement, 44% of current heifers were below target at mating and 65% were below target pre-calving (22 months of age). At 22 months of age, current heifers were on average nearly 42 kg below target live weight. By failing to achieve targets near calving, farmers are not capturing potential milk production benefits.

RC, Handcock, TJ Lopdell, and LR McNaughton

Proceedings of the New Zealand Society of Animal Production, Volume 76, Adelaide, 3-7, 2016