EFFECT OF REPLACEMENT RATE, PRODUCTION SYSTEM AND BEEF PRICE ON TOTALHERD EFFICIENCY

The influence of replacement rate (R), price (c/kg carcass weight) and two production systems on total herd efficiency was investigated. R w as assumed to be either 15% (minimum), 19% (point in between) or 23% ( maximum). Percentage differences (minimum, point in between, maximum) in beef prices for the period 1984 to 1992 (RSA Livestock and Meat Sta tistics) were calculated for eight-month-old weaners vs. cull cows and 18-month-old market animals vs. cull cows, respectively. These percen tage price differences were used to calculate relative income per hect are (I/ha) for two production systems, namely, an 8/18 month system (s teers sold at eight months of age/surplus heifers sold at 18 months of age) and an 18/18 month production system (all market animals sold at 18 months of age). From the results it was clear that maximum R is ap plicable on systems where cull cows are, on a per-animal basis, of hig her value than both eight-month-old weaners and Ii-month-old market an imals. Comparison between the two production systems based on adjusted I/ha and 20% R (assumed as standard practise in South Africa) has sho wn the 18/18 month system to be more efficient. This study also indica ted that longevity is not important for maximizing efficiency, since R should be maximized.