The effects of feeding frequency on the intake and performance of cows grazing mixed pasture : a thesis presented in partial fulfilment of the requirements for the degree of Master of Agricultural Science in Animal Science at Massey University, Palmerston North, New Zealand

Abstract

A grazing trial was carried out to compare herbage intake and milk production by dairy cows and observe their grazing behaviour when given all pasture in one break or in four breaks per day. The experiment was carried out in two periods using a total of 24 animals. Period I with a common herbage allowance of 30 kg DM/cow/day from week 7 to week 9 of lactation and Period II with a common herbage allowance of 40 kg DM/cow/day from week 10 to week 11 of lactation. The 24 cows which were selected from the high and low breeding index herd were allocated at random to either one break (1B) or four breaks (4B) and used for period I. Sixteen cows were drawn from the 24 cows and used for period II; they were also randomly allocated to the treatments. Grazing behaviour of cows was observed during Period II of the trial on two separate occasions. Herbage allowance and herbage intake were estimated by the sward cutting technique. The control group consumed 12.3 and 15.6 kg DM/cow/day while the four breaks (the treatment group) consumed 11.8 and 15.3 kg DM/cow/day for Period I and Period II respectively. Treatment did not have a significant effect. Milk production, liveweight and body condition score were measured. Treatment had no significant effect on any of these measurements (except for lactose % in Period H). There was a slight increase in milk production for the treatment group in Period II but the difference was not statistically significant (23.4 versus 22.8 kg milk yield and 1.0 versus 0.9 kg milk fat yield per day). Grazing time was similar for both groups and there were no significant changes in liveweight and body condition score. It was concluded that for the condition and herbage allowances used in this experiment, the frequency of herbage allocation had no significant effect on performance of cows.