Pasture Composition, as Affected by Grazing Management, and its Effects on Milk Production by Grazing Dairy Cows

Prcgrazing herbage mass was controlled al higher or lower levels by grazing management (intensity or frequency). Three of the experiments used ryegrass (Lolium perenne L.) and white clover (Trifolium repens L.) swards, while the fourth included Grasslands Matua prairie grass (Bromus willdenowii Kunth.) and white clover swards. The high mass swards generally contained higher proportions of dead matter and stem, and the herbage from these swards was always less digestible. When offered a common daily herbage allowance, cows grazing on the high mass swards produced less milk than those on the low mass swards. The data suggest that it may be possible to maintain the feeding value of prairie grass pastures up to higher herbage masses than can be done in rycgrass pastures. In one experiment cows were offered a common daily allowance of green leaf dry matter from three swards which differed In morphological and chemical composition. Milk yield did not differ between the three swards.