Dry matter intake and body condition score gain of dairy cows offered kale and grass

Abstract

An outdoor grazing study conducted with 45 pregnant, dry dairy cows for 47 days during the winter period measured dry matter (DM) utilisation, DM intake, forage disappearance, body condition score (BCS) and liveweight (LW) of cows fed 11 (K11) or 14 (K14) kg of kale DM per day or 11 (G11) kg DM Italian ryegrass per cow per day. Cows were offered 3 kg DM barley straw/cow/day at 0800 h and their daily forage allowance at 0900 h. Within 6 hours of being offered a fresh forage allocation, cows had consumed more than 86% of their apparent daily DM intake with cumulative DM intake of 10.4, 10.5 and 7.3 kg DM/cow for K11, K14 and G11, respectively. Daily percentage DM utilisation averaged over the 47 days of the trial was higher for K11 (96%) and K14 (88%) than for G11 (70%), leading to higher apparent daily DM intake for K14 (12.1 kg) and K11 (10.5 kg) than for G11 (7.9 kg DM). Liveweight and BCS gain during the 47 days were higher for K14 (45.4 kg LW and 0.3 BCS units) and G11 (46.8 kg LW and 0.3 BCS units) than for K11 (30.1 kg LW and 0.2 BCS units). This study indicates that compared with offering the common industry allowance of 11 kg kale DM/cow/day, increasing the allowance to 14 kg kale DM/cow/day or offering grass at 11 kg DM/cow/day may lead to higher BCS and LW gain, although all regimes failed to meet expectations of cows gaining 0.5 BCS units during the winter feeding period.