Bartholomew P W, Khibe T, Little D A, Ba S
International Livestock Centre for Africa (ILCA), Bamako, Mali.
Trop Anim Health Prod. 1993 Feb;25(1):50-8. doi: 10.1007/BF02236886.
Work oxen supplemented at different levels during a feeding period of 3 months, were divided into 3 groups of average weight change -25, +35 and +70 kg and worked under loadings of either 7.5 or 12.5 kgf/100 kg of liveweight for 2 weeks, in order to assess the impact of dry season supplementation on capacity for work. At approximately equal levels of stress in work, manifest in maximum heart rate one minute after ceasing work (MHR), oxen with higher dry-season weight gain produced higher levels of work output, in proportion to their increased body weight. Rate of work and mean daily work output increased from the first to the second week of work, in spite of average daily weight losses of 2.63 kg throughout the period. Decline in rate of working through each day was continuous and essentially linear with relation to distance worked. The time taken to cover 1 km increased at an average of 0.16 and 0.68 min/km for light and heavy loadings respectively. Although MHR appeared to provide a retrospective measure of the level of stress attained in work, it was of limited use as a predictor of reasonable work demand. Maximum heart rate was related to work output (MJ) and animal liveweight (kg), as follows: MHR = 17.7 (+/- 3.94) WO - 0.15 (+/- 0.080) LWT + 118.5 (r2 = 0.70 P < 0.01).
在为期3个月的饲养期内，按不同水平对役用牛进行补饲，将其分为平均体重变化分别为-25、+35和+70千克的3组，并在相当于7.5或12.5千克力/100千克活重的负荷下工作2周，以评估旱季补饲对工作能力的影响。在工作压力水平大致相同（以停止工作一分钟后的最高心率表示）的情况下，旱季体重增加较多的牛，其工作产出水平更高，且与体重增加成比例。尽管在此期间平均每天体重减轻2.63千克，但工作速率和平均日工作产出从工作第一周到第二周有所增加。每天工作速率的下降是持续的，且与工作距离基本呈线性关系。轻载和重载时，每行走1千米所需时间平均分别增加0.16和0.68分钟/千米。尽管最高心率似乎可用于回顾性评估工作中所达到的压力水平，但作为合理工作需求的预测指标，其作用有限。最高心率与工作产出（兆焦）和动物活重（千克）的关系如下：最高心率 = 17.7（±3.94）×工作产出 - 0.1
