Optimum white clover content for dairy pastures

Abstract

In February 1996, 48 Friesian and Jersey cows grazed pastures containing nominally 0, 25, 50 or 75% of dry matter (DM) as white clover with the balance mainly C4 grasses at either ad lib. (50 kg DM/cow/day) or restricted (25 kg DM/cow/day) allowances. The aim of the trial was to measure the effect of clover content on milk yield and composition, and to determine the optimum clover content for milk production. Milk yields of cows on the ad lib. allowance grazing 25% clover were 22% higher (P<0.05) than yields of cows grazing 0% clover. Milk yields on 50 and 75% clover were similar, 33% higher (P<0.05) than for cows grazing 0% clover. The differences were similar for cows on the restricted allowance. Clover content had little effect on milk composition except for a decrease in fat % with increasing clover content. The trial showed increased milk yields were owing to both increased intakes associated with high clover diets, and the higher nutritive value of the clover. Results showed that a clover content of 50% is a realistic target to increase milk yields considerably. Increasing clover content above 65% would do little to increase milk production further. Keywords: Friesian cow, herbage intake, Jersey cow, milk composition, milk yield, nutritive value, perennial ryegrass, smooth witchgrass, summer grass, white clover