Seasonal Patterns in Food Intake, Food Conversion Efficiency, Live Weight Gain and Carcass Weight in Feedlot Cattle

An analysis of data collected over 2 years from a commercial feedlot in Queensland was conducted to determine the seasonal patterns in cattle performance parameters, namely daily feed intake, food efficiency, live weight gain and carcass weight. Daily feed intake was influenced by a combination of day length and air temperature so that increasing day length was associated with a concomitant increase in feed intake. However, as temperature increased, the effect of day length was overridden and feed intake declined. These results suggested that the negative effect of high temperatures on feed intake was greater than the positive effect of increased day length, resulting in intake depression. In the winter period the lag in feed intake response to the change in day length and temperature was 4 to 6 weeks. Seasonal oscillations in food conversion efficiency closely reflected the oscillations in average gain, with a variation in amplitude but a similar phase. There were clearly defined seasonal cycles in food conversion efficiency, live weight gain and carcass weight with maximum values in summer and minimum values in winter. The results indicated that while feed intake declined as temperature increased, maintenance costs were reduced, and summer-fed cattle were more efficient at converting feed into live weight gain. The results indicate that the profitability of feedlot cattle changes with season and that feedlot managers need to be aware of the presence of seasonal effects so that optimum management can be provided.