Abstract

Dairy heifers need to achieve average daily gains (ADG) that allow them to reach liveweight targets. The aim of this experiment was to measure the effects of grazing 6-month-old dairy heifers on alternative feeds, over the summer period. Sixty 6-month-old Friesian-Jersey crossbred heifers were assigned to one of three treatments (pasture (P), conserved forages (C) or lucerne (L), with all treatments receiving supplementary meal. For the 6-week experiment, feed allowance was based on liveweight gain required to meet liveweight targets. Heifers were weighed at 0, 3 and 6 weeks of the treatment period. Wither height, crown-to-rump length and girth circumference were measured at the start and end of the experiment. L heifers had a greater (P<0.05) average daily gain (1.22 + 0.03 kg/day) than P heifers (0.57 + 0.03 kg/day), and C heifers were intermediate (0.78 + 0.03 kg/day). L and C heifers had a greater (P<0.01) increase in wither height (0.15 + 0.01 cm/day and 0.14 + 0.01 cm/day respectively) than P heifers (0.11 + 0.01 cm/day). L heifers had the greatest (P<0.05) increase in girth circumference (0.30 + 0.02 cm/day, compared with P and C heifers: 0.22 + 0.02 cm/day and 0.16 + 0.02 cm/day respectively). A combined diet of lucerne and meal during drought conditions increased ADG resulting in a greater proportion of heifers reaching liveweight targets.

de RP, Clifford, RE Hickson, NP Martin, and PJ Back

Proceedings of the New Zealand Society of Animal Production, Volume 74, Napier, 29-34, 2014