Growth and feed efficiency of range performance tested beef bulls in the arid sweet bushveld of South Africa

• 作者: Andre Bothma Julius Sebei Kabelo Madia Khathutshelo Nephawe Lesley Mashiloane
• 来源期刊: 动物科学期刊(英文)
• 学科: 医学
• 关键词: BULL Performance Testing AVERAGE DAILY GAIN Kleiber Ratio
• 年，卷（期）: 2012,（4）
• 页码范围: 258-264
• 页数: 7页
• 分类号: R73

摘要

Data consisting of test performance records of 725 bulls was analysed to evaluate trends for growth and feed efficiency, and to determine environmental factors that influence growth of range performance tested bulls in the arid sweet bushveld of South Africa. Performance data were subjected to regression procedures to estimate parameters of the slope (β) and intercept (α) for average daily gain (ADG) and Kleiber ratio (KR). Mixed procedures were applied to test for sources of variation in ADG and KR. There was an increase of 3.481 g/day/year and 0.528 g/day/ year in ADG for Nguni and Bonsmara bulls, respectively. The ADG trends’ respective feed efficiency as reflected by KR was 0.093 and 0.059. Herd of origin and test-year were the sources of variation for ADG while the variation in KR was due to the herd of origin, test-year, start-age and start-weight. Results indicated a steady increase in ADG and KR for range performance tested bulls in the arid sweet bushveld.