Foraging behaviour of dry cows offered kale and grass once or twice a day in winter: A dissertation submitted in partial fulfilment of the requirements for the Degree of Bachelor of Agricultural Science (Honours) at Lincoln University

Abstract

Intake and foraging behaviour of dairy cows grazing kale (K) or grass (G), on either a once (1) or twice (2) a day allocation was measured during week 4 and 6 of a 6 week winter feeding period. Cows were offered either 11 kg of forage + 3 kg of straw once daily, or, 5.5 kg of forage + 1.5 kg straw twice daily. The average % dry matter (OM) utilisation over the two sample days of Kxl (97%) and Kx2 (94%) were higher than Gxl (83%) and Gx2 (80%). Apparent DM intake (kg DM/day) was higher for Kx1 (10.7) and Kx2 (10.4) than for Gx1 (9.1) and Gx2 (8.7) due to the lower% utilisation of grass. Grazing behaviour was altered by both forage type and frequency of allocation. Within 6 hours of being offered a fresh break, cows being fed once daily on kale (Kx1) had consumed over 90% of their apparent daily intake at 10.0 kg DM/cow, and cows being fed once daily on grass (Gxl1) had consumed over 80% of their apparent daily intake at 7.6 kg DM/cow. Both Kx1 and Gx1 treatments had an increased duration of the first meal compared to Kx2 and Gx2 treatements by 42 and 27 minutes respectively, as well as the the most minutes total spent grazing throughout the day. Cows in the Kx2 and Gx2 treatments also spent a greater proportion of the morning searching for food. Biting rate was not affected by either crop type or frequency of allocation in the current experiment. Based on these results, better utilisation, higher yields and therefore increased daily intake, indicate a greater possibility of reaching a calving body condition score (BCS) target of 5.0 is more achievable on kale. By offering a forage twice daily, cumulative intake may be spread more evenly throughout the day, which is proposed to benefit rumen function.