Observations on the diet selected by Friesian cows grazing tropical grass and grass-legume pastures
1986
Cowan, R.T. | Davison, T.M. (Queensland Dept. of Primary Industries, Ipswich (Australia). Mutdapilly Research Station) | Shephard, R.K. (Queensland Dept. of Primary Industries, Townsville (Australia). Ooonoonba Veterinary Lab.)
The grass pasture was stocked at 2.0 and 3.5 cows per ha, and received 200 and 400 kg N per ha per year at each stocking rate. The grass-legume pasture was stocked at 2.0 cows per ha and received no nitrogen fertilizer. All pastures were grazed on a rotation of one week grazing, three weeks spelling. With pure grass pastures there was a rapid decline in the leaf content of the diet during the first three days of the week, and an associated increase in stem and dead material. Crude protein content of the diet exceeded 12 percent in the dry matter only during the first two days of each week. The effects of stocking rate and fertilizer level were evident early and late in the week, but were small in relation to the changes as the pasture was grazed down. There was less variation in the composition of the diet of cows grazing grass-legume pastures, but the crude protein content of the diet again only exceeded 12 percent in the first two days of the week. For grass pastures the results show a close association between leaf percentage in the diet and both leaf yield on offer and total pasture yield on offer. Grazing time was reduced when yield of grass leaf was less than 1.0 t DM per ha. Milk production varied by up to 25 percent during the week, with peak values being on days 2 and 3 and the minimum value on day 7.
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