Abstract

`Barkant` turnips and `Superchow` sorghum were compared as summer-autumn crops for lactating cows. Crops were fed at three levels (0, 4 and 8 kg DM/cow/d) to supplement pasture offered at a constant allowance. Sixty twin cows were used in two experimental periods in February and March 1997. Feeding 4 or 8 kg DM/cow/day increased milksolids (MS) yield/cow by 29% or 36% for turnips, and 26% or 32% for sorghum compared with pasture alone. Turnips gave responses of 58g and 45g MS/kg DM offered, at the lower allowance, in summer and autumn respectively, compared with 45g MS/kg DM in both seasons for sorghum. For both crops, increasing allowance from 4 to 8 kg further increased MS yield. Crop utilisation was lower on sorghum than turnips but substitution rates for turnips were higher than for sorghum at both allowances in both summer and autumn. This means that although both crops have a `pasture sparing` effect, sorghum contributed more to increased per cow intake.

SL, Harris, DA Clark, CD Waugh, PJA Copeman, and AR Napper

Proceedings of the New Zealand Society of Animal Production, Volume 58, , 121-124, 1998