The effects of a number of management practices on chiller beef production in Victoria

Abstract

Analysis of data for 72 Aberdeen Angus cows and their calves revealed the following significant relationships. (1) There was an inverse relationship between the total pre-weaning liveweight increase of calves and the liveweight change of their dams during the first half of lactation (r = –0.486; P<0.001) but not during the second half (r = +0.005; N.S.). Good dams "milked the flesh" during the period of maximum calf growth. (2) This is a maternal characteristic, not caused by greater demand of greedy feeders. (3) Steers made greater bone growth than heifers at all times of the year although during store periods both sexes gained (or lost) liveweight at the same rate. (4) Cattle unsupplemented in the store period tended to catch up with supplemented animals in the spring. Even when all treatment effects, including supplementary feeding, were analysed out, there remained a significant negative partial correlation between gains in the store and the subsequent spring fattening period (r = –0.20, P=0.05). It is suggested that the relative immaturity of slow-gaining animals at the start of the fattening period accounted for their compensatory gain. (5) "Compensatory growth" appeared to be most strongly demonstrated by older cattle: those which did better in the store period entered the spring in an advanced store condition and their weight gains were high energy fatty tissues, as compared with the high protein, low energy gains of lean animals. (6) The above notwithstanding, there was a positive partial correlation between the total lifetime rate of gain and the rate in the 9 month store period (r = +0.371; P = 0.01) and in the 3 month fattening period (r = +0.557; P< 0.001) prior to slaughter.