Comparative dairy production of Jerseys and Friesians

Abstract

Eight herds each of 24 Friesian cows were stocked at 3.7 cows/ha on separate farmlets during 1982-83 and 1983-84. Annual production per hectare averaged 710 kg fat, 537 kg protein, 740 kg lactose and 16.7 t solids corrected milk (SCM). Annual DM intake was 15.8 t/ha and live weight (LW) during lactation, 1487 kg/ha. In a contemporary farmlet trial at an adjoining dairy, 4 purebred Jersey herds each of 15 cows were stocked at 2.8, 3.3, 3.8 and 4.3 cows/ha. Regression analysis was used to derive estimates of the performance of the Jerseys at the same stocking rate, and at a stocking rate that resulted in the same LW/ha, as the Friesians. At a common stocking rate of 3.7 cows/ha, the Friesians were estimated to produce 7, 15, and 13% more fat, protein, and SCM/ha than the Jerseys. Annual conversion efficiency (g milk constituent/kg DM) of the Friesians was estimated to be 10% higher for fat and 18% higher for milk solids than the Jerseys. At the same LW/ha, requiring a Jersey stocking rate of 4.21 cows/ha, the Friesians were estimated to outproduce the Jerseys by 3, 13 and 10% for fat, protein and SCM/ha respectively. Annual conversion efficiency for the Friesians was estimated to be 15 and 25% higher for fat and milk solids respectively than for the Jerseys. For Jerseys, estimated maximum yields per hectare of milkfat and milk solids were at 4.45 and 4.37 cows/ha and were 686 kg fat/ha and 1761 kg milk solids/ha; 4 and 13% respectively less than produced by the Friesians stocked at 3.7 cows/ha. The superior production of the Friesians was due to their higher food conversion efficiency, not to higher food intake.