Evaluation of production parameters of bulls of four beef breeds in the Vrede district of South Africa

Abstract

objective of the study is to investigate the economic important performance traits of beef cattle bulls in a production environment. Performance data was collected, from 2001 to 2012 on 1318 bulls comprising of four breeds [Beefmaster (n = 447), Bonsmara (n = 342), Braford (n = 202) and Nguni (n=327)], from the Eastern Free State Veld Bull Club (EFSVC). Bulls were evaluated on performance traits at the farm Paardenplaats over a period of between 155 to 227 days. Bulls arrived in the first week of September. The composite breeds started and finished the performance evaluation period heavier (P < 0.05) than the Nguni (NG) bulls each year throughout the study period. While the Beefmaster (BM) bulls showed higher (P < 0.05) initial live weight (ILW) and final live weight (FLW) than both the Braford (BF) and Bonsmara (BO) bulls in some of the years during the study period. The BM (723 g/day ± 5.4) and BF (724 g/day ± 8.0) bulls had higher (P < 0.05) average daily gain (ADG) than the BO (699 g/day ± 6.1) bulls. All three composite breeds had higher (P < 0.05) ADG than the NG (633 g/day ± 6.9) bulls. However the NG (8.94 ± 0.071) bulls were more efficient (P < 0.05) in terms of Kleiber ratio (KR) compared to the BO (8.36 ± 0.062), BF (8.35 ± 0.082) and BM (8.22 ± 0.055) bulls. The BM (33.51 cm ± 0.125) bulls had larger (P < 0.05) scrotal circumference (SC) than the BO (32.79 cm ± 0.146) bulls. While the BM, BO and BF (33.19 cm ± 0.189) bulls had larger (P < 0.05) SC than the NG (30.30 cm ± 0.170) bulls. In addition the NG (10.38 % ±0.059) bulls had larger (P < 0.05) SC as a percentage of FLW than the BO (9.09 % ± 0.051), BF (8.70 % ± 0.066) and BM (8.63 % ± 0.044) bulls. The NG (138.31 cm2 ± 1.832) bulls had a smaller (P < 0.05) pelvic score (PS) than the BF (160.20 cm2 ± 1.694), BO (161.30 cm2 ± 1.376) and BM (164.16 cm2 ± 1.256) bulls. However, the NG (49.62 % ± 0.592) bulls had higher (P < 0.05) PS as a percentage of FLW than the BO (45.52 % ± 0.444) bulls, while both these breeds had higher (P < 0.05) values compared to the BM (43.43 % ± 0.406) and BF (42.77 % ± 0.547) bulls. The composite breeds had higher (P < 0.05) body condition scores (BCS) at the start of the performance evaluation than the NG bulls, with no difference (P > 0.05) at the end of a specific year. The NG bulls had a lower (P < 0.05) hair coat score (HCS) than the composite breeds. Variation for both muscle score (MS) and temperament score (TS) was observed between the breeds. Auction prices were only available from year 6 until year 12. Over the performance evaluation period a linear increase in the weaner price was observed as the price for yellow maize increased (P < 0.05; R2 = 0.52), and as the weaner price increased there was a linear increase in the price obtained for the BF bulls on the auction (P < 0.05; R2 = 0.73). However, no regression (P > 0.05) fitted the data between the prices received for the BF bulls on the auction and the yellow maize price. In year 9 a linear (P < 0.05; R2 = 0.45) and quadratic (P < 0.05; R2 = 0.57) regression fitted the data between ADG and the auction prices received for the BF bulls. A quadratic regression (P < 0.01; R2 = 0.97) fitted the data between the auction prices received for the BO bulls and the KR values for the BO bulls in year 9. In year 11 a linear regression (P < 0.05; R2 = 0.24) fitted the data between the auction prices received for the BM bulls and their KR values in year 11. In year 6 the auction prices received for the BO bulls increased linear (P < 0.05; R2 = 0.27) as their MS increased and in year 9 a quadratic regression (P < 0.01; R2 = 0.99) fitted the data for these two parameters. In year 7 a linear (P < 0.01; R2 = 0.50) and quadratic (P < 0.01; R2 = 0.56) regression fitted the data between the auction prices received for the BM bulls and their MS. In year 10 a linear (P < 0.01; R2 = 0.39) and quadratic (P < 0.01; R2 = 0.44) regression fitted the data between the auction prices received for the BM bulls and their SC. The auction prices received for the BO bulls increased linear (P < 0.05; R2 = 0.35) as their SC increased in year 11. This study is evidence that there exist variation within breed as well as between breeds. Therefore, commercial farmers should pay attention to these production parameters when selecting a sire in order to improve the genetic potential of their herd.