Abstract

Many heifers on New Zealand dairy farms fail to reach their target live weight. This failure leads to lost milk production and poorer reproductive performance. This study investigated effects of breed and region on heifer live weight and also effects of pre-calving heifer live weight (18–21 months) on milk production. Less Friesian heifers reached their target live weight than Jerseys, or Crossbreds (85.3 versus 89.3 versus 88.1%; P <0.001). Heifers born in Otago (91.9%) and Taranaki (91.8%) were the closest to achieving their target live weight, whilst those born on the West Coast (85.6%) and Northland (86.0%) had the greatest number of heifers not reaching their target. Heifers that had only one calving recorded on the database were a significantly lower percentage of target live weight than those heifers that had two calvings recorded (83.5% versus 87.1%; P <0.001). In heifers with a live weight record between 18 and 21 months of age, every 1% increase in the percentage of target live weight attainedwas associated with an increase in milk volume of 23 ± 0.6 litres in the first lactation and 24 ± 0.9 litres inthe second lactation. Further work is required on the economics of feeding heifers to achieve their target live weight.

LR, McNaughton, and T Lopdell

Proceedings of the New Zealand Society of Animal Production, Volume 73, Hamilton, 103-107, 2013