Abstract

The performance of overseas (OS) and New Zealand (NZ) Holstein Friesian (HF) dairy heifers was compared when fed an all-pasture diet (Grass) or a total mixed ration (TMR) throughout lactation. The four treatments were NZ Grass (n=14); OS Grass (n=9); NZ TMR (n=15); and OS TMR (n=10). Compared with NZ HF, OS HF had a higher live weight and produced more milk, but milksolids yield, efficiency of milksolids production, and persistency of lactation were not different. Compared with HF fed Grass, HF fed TMR produced more milk and milksolids, were more efficient, had a greater persistency of lactation, and ended lactation with a greater body weight. The OS HF genotype was unable to maintain acceptable body condition and live weight on an all-grass diet. This raises serious questions regarding the sustainability and suitability of these genetics for seasonal all-pasture dairying systems.

ES, Kolver, AR Napper, PJA Copeman, and LD Muller

Proceedings of the New Zealand Society of Animal Production, Volume 60, Hamilton, 265-269, 2000