The Effect of Supplementary Barley Upon Growth and Efficiency of Food Conversion in Calves Kept at High Grazing Intensity

Abstract

Three groups of Hereford x Friesian steer calves, bom in early January 1969, were strip-grazed on eqoal areas of a sward of S321 perennial ryegrass from May to September inclusive, and received kibbled barley at the rate of nil, f % or \\% of liveweight per day. Adjustments were made to the number of animals per group in order to maintain the same high grazing intensity (defined as 8 cm stubble height in grazed areas) on all treatments. The animals receiving supplementary barley gained weight at a rate 17-19% higher than the controls, but there was no significant difference in growth rate between the high and low levels of supplementation. The efBdency of conversion of barley was only 5-12 kg per animal liveweight gain/100 kg barley OM.The bigb level of supplementation resulted in an increase in stocking rate of 36 % over tbat of tbe control group, and an increase in liveweigbt gain per unit area of land grazed of 63%. The additional liveweigbt gain due to supplements, expressed per unit area of laiid grazed, was relatively constant at 21-24 kg liveweigbt gain/ 100 kg barley OM consumed.