摘要
Current standard protocols for feed efficiency trial in beef cattle require a trial period of at least 70 days. This was determined to be the minimum trial duration to obtain adequate estimates of average daily gain with infrequent collection of animal weights. Modern automated weighing systems (e.g., GrowsafeBeef, Intergado) enable collection of multiple body weights each day without the need to handle cattle. Due to the high volume of data generated, it is likely that adequate estimates of rate of gain may be obtained with a shorter trial duration. Data were obtained during two consecutive feed efficiency trials (21 and 22) with yearling Nelore bulls at Rancho da Matinha, Uberaba, Brazil. Individual ADG were estimated by regression of BW vs. time. During Trial 21, body weights were taken by manual weighing every 14 days, for 70 days. Trial 22 involved automated weighing (Intergado) for 49 days. For Trial 21, the mean ADG was 1.113 (se 0.1079) kg/d, and 95% of the animals had se below 0.2 kg/d. In Trial 21 with automated weighing, the mean ADG were 1.248 (se 0.542), 1.164 (se 0.430, 1.097 (se 0.351, 1.114 (se 0.254) and 1.080 (se 0.234) after 14, 21, 28, 35, 42 and 49 d, respectively, and 85% had se below 0.3 kg/d. These findings suggest that precision of estimates of ADG is a valid criterion to determine optimal trial duration. Further study will be required to determine optimal trial durations for different types of cattle, diets and facilities.
摘要译文
当前肉牛饲料效率试验的标准协议要求至少70天的试验期。确定这是最短的试验持续时间，以便在不经常收集动物体重的情况下获得平均日增重的足够估计。现代化的自动称重系统（例如GrowsafeBeef，Intergado）可以每天收集多个体重，而无需处理牛。由于生成的数据量很大，可能可以在较短的试用期间内获得足够的收益率估计。在巴西Uberaba Rancho da Matinha的一岁Nelore公牛连续两次饲料效率试验（21和22）中获得了数据。通过BW对时间的回归来估算单个ADG。在第21次试验期间，每隔14天以手动方式称重体重，持续70天。试验22涉及49天的自动称重（Intergado）。在试验21中，平均日增重为1.113（se 0.1079）kg / d，95％的动物的se低于0.2 kg / d。在具有自动称重功能的试验21中，在14、21、28、35、42和49之后，平均ADG分别为1.248（se 0.542），1.164（se 0.430、1.097（se 0.351、1.114（se 0.254）和1.080（se 0.234）） d分别为0.35％/ d和85％。这些发现表明，ADG估算的准确性是确定最佳试验持续时间的有效标准。需要进一步研究以确定不同类型的牛，饮食和设施的最佳试验持续时间。
Roberto Sainz [1]. 201 Precision of gain estimates for beef cattle with an automated weighing system[J]. Journal of Animal Science, 2019,97(Sup3)