Abstract:
The objective of this study was to investigate the growth performance, feed conversion efficiency and other production traits of beef cattle performance tested on the farm. Performance testing records (collected from 2000 to 2004), of 444 bulls comprising of six breeds [viz. Aberdeen Angus (n = 42), Beefmaster (n = 135), Bonsmara (n = 97), Drakensberger (n = 64), Nguni (n = 50) and Simbra (n = 56)] from the eastern Free State, Veld Bull Club (VBC) were obtained and analysed. Bulls were performance tested on the farm (Poortije in Vrede district) for 205 days (16.53 s.d.) and finished-off in a feedlot for 100 days. Upon the completion of the entire test period, the bulls were auctioned. Traits studied were: average daily gain (ADG), Kleiber ratio (KR) and veld feed conversion ratio (VFCR), body conditions score (BCS), muscling score (MS), temperament score (TS), tick count (TC), scrotum circumference (SC) and selling price (SP). An analysis of variance with the General Linear Model (GLM) was used to determine the significance within a breed between years, between breeds within a year, the interaction of year x breed, and breeders (breed x year) for all the dependent variables. Aberdeen Angus bulls showed a significant difference for all traits analysed except for SC and SP. Beefmasters did not only differ in BCS and TS. Bonsmaras differed in all traits analysed except for FWT, SC and SP. Unlike the other breeds, the Drakensberger had more traits that they showed no significant differences viz. IWT, FWT, MS, TS and SP. The Nguni showed significant difference in all traits analysed except for IWT, TS and SC. Finally, the Simbra also did not differ significantly in five of the eleven traits measured viz. FWT, MS, TC, SC and SP. According to these results, there is a significant variation within beef cattle breeds on rangeland in certain performance and other production traits such those measured in this study. This suggests that, although selection for desirable traits within-breed may be slow, the within-breed selection and exploitation has a role to play in improving long-term herd functional efficiency. During the feedlotting period, none of the breeds showed a significant difference in ADG, suggesting that, given a favourable environment, each animal will have an equal opportunity to perform at its optimum genetic potential. This further implies that in a production environment where feed resource is not the limiting factor, higher production efficiency may well be accomplished by each animal.
