Effect of fasting on liveweight and subcutaneous fat depth of cattle

Two groups of British bred steers, mean liveweight 384 kg, were held off feed for 5 days with or without water and their liveweights and subcutaneous fat depth at two points determined daily. Fat depths were determined using a Scanogram. The aim was to determine the possible effect of management during marketing on some of the carcase characteristics likely to be used for market specification in Australia. The curvilinear decrease in liveweight was less in the group with water available although their mean daily consumption of water was low (61 head-1). No difference in the rate of change of fat depth between the group with water and the group without it was detected. There was no detectable change in fat depth measured at a point 2.5 cm from the edge of the eye muscle (FD2) whereas fat depth over the eye muscle (FDI) appeared to increase in the 5 day period (0.043 mm day-1). Rates of change of fat depth at the two sites were not correlated. The rate of change of FD2 was negatively correlated (r = 0.45) with initial FD2 fat depth; in animals with an initial FD2 of 5 mm, FD2 decreased with fasting.