Gitau G K, McDermott J J, McDermott B, Perry B D
International Livestock Research Institute, P.O. Box 30709, Nairobi, Kenya.
Prev Vet Med. 2001 Oct 11;51(3-4):149-60. doi: 10.1016/s0167-5877(01)00243-4.
The association between mean daily weight gain, Theileria parva infections, clinical East Coast fever and other possible determinants of weight gain were examined in a longitudinal observational study that was conducted in cohorts of female calves from five agro-ecological zone (AEZ)-grazing strata. The strata were upper-midlands (UM) 1 zero-grazing, UM 1 open-grazing, UM 2 zero-grazing, UM 4 zero-grazing and UM 4 open-grazing. In total, 225 calves on 188 smallholder dairy farms were visited within the first 2 weeks of life and thereafter at biweekly intervals up to the age of 6 months between March 1995 and August 1996. During each visit, the calves were weighed and other calf-management practices in the farm during the visit such as housing, feeding and tick control also were recorded. Other events such as morbidity and mortality between or during the visits were also recorded. The overall mean daily weight gains were 0.24-0.29 kg (S.D.=0.17-0.22 kg) and were lower than the recommended targets for smallholder farms of 0.40-0.50 kg. The major tendency in variability of daily weight gains was due to visit-to-visit variation (especially in calves >3 months old). Differences in mean daily gains were associated with AEZ-grazing strata and calf-level factors that included breed of calf, calf sickness, incidence of ECF, feeding of milk, concentrate feeds and minerals and interaction between calf age and AEZ-grazing strata (P<0.05). ECF and other calf sicknesses exerted a temporal effect on calf-growth at the height of illness and immediately after; calves later recovered the lost growth except where other factors such as poor calf nutrition prevailed. Improvement in calf-growth in Murang'a District is achievable and extension services should continue to target individual-calf-level management practices.
在一项纵向观察研究中，对来自五个农业生态区（AEZ）放牧层的雌性犊牛队列进行了检查，以探究平均每日体重增加、泰勒虫感染、临床东海岸热以及其他可能的体重增加决定因素之间的关联。这些层次包括上中部地区（UM）1的零放牧、UM 1的开放式放牧、UM 2的零放牧、UM 4的零放牧和UM 4的开放式放牧。1995年3月至1996年8月期间，在犊牛出生后的前两周内，对188个小农户奶牛场的225头犊牛进行了走访，此后每两周走访一次，直至6月龄。每次走访时，对犊牛进行称重，并记录走访期间农场的其他犊牛管理措施，如饲养、喂食和蜱虫控制。还记录了走访之间或走访期间的其他事件，如发病率和死亡率。总体平均每日体重增加为0.24 - 0.29千克（标准差 = 0.17 - 0.22千克），低于小农户农场推荐的0.40 - 0.50千克的目标。每日体重增加变异性的主要趋势是由于每次走访之间的差异（特别是在3月龄以上的犊牛中）。平均每日增重的差异与AEZ放牧层以及犊牛水平因素有关，这些因素包括犊牛品种、犊牛疾病、东海岸热发病率、牛奶喂养、精饲料和矿物质，以及犊牛年龄与AEZ放牧层之间的相互作用（P < 0.05）。东海岸热和其他犊牛疾病在疾病高峰期及之后对犊牛生长产生了暂时影响；犊牛后来恢复了失去的生长，除非存在其他因素，如犊牛营养不良。穆朗加区犊牛生长的改善是可以实现的，推广服务应继续针对个体犊牛水平的管理措施。
