Aref Nasr-Eldin M, El-Sebaie Ali, Hammad Hammad Zaghloul
Department of Animal Medicine, Faculty of Veterinary Medicine, Assiut University, Assiut, Egypt.
Animal Health Research Institute, Sohag, Egypt.
Vet World. 2016 Jun;9(6):579-86. doi: 10.14202/vetworld.2016.579-586. Epub 2016 Jun 12.
The present study was designed to: (1) Investigate the effect of weaning time on various metabolic indices and growth pattern in buffalo calves compared to cow calves under field condition and (2) Shed light on the potential relationship between early weaning, growth metabolites, and suboptimal growth (ill-thrift) in buffalo calves.
A total number of 18 neonatal calves of both sexes and species (cattle and buffalo) were included in the study. Animals were divided into three groups according to their age at weaning as following: Cow calves (n=8) weaned at 4.5 months, buffalo calves (n=6) weaned at 3.5 months (early-weaned), and buffalo calves (n=4) weaned at 5.5 months (late-weaned). Morphological traits, growth metabolites, and hormonal profile were measured at monthly interval over the period of the study and around the time of weaning (2 weeks pre- and post-weaning).
The obtained results showed that the trend of growth pattern was significantly increased in a linear pattern in cow calves and late-weaned buffalo calves, whereas early-weaned buffalo calves showed sharp decline in their body weight (BW) post-weaning. By the end of the study, early-weaned buffalo calves showed the lowest BW gain (ill-thrift). There is a positive association between the morphological traits and various growth metabolites and hormonal indices. A significant decrease (p<0.05) in the concentrations of growth hormones (insulin-like growth factor-1 [IGF-1] and insulin) and other metabolites were reported in early-weaned buffalo calves compared to other animals. There is no association between stress indices (cortisol level and neutrophil to lymphocyte ratio) and growth rate.
Suboptimal growth rate (ill-thriftiness) is common in early-weaned buffalo calves and is attributed to low blood levels of growth metabolites, in particularly, IGF-1. In addition, the strong positive associations between concentrations of IGF-1 and morphological characters of growth suggest that IGF-1 is a reliable indicator for assessing metabolic status of individual calves.
本研究旨在：（1）在田间条件下，调查与奶牛犊牛相比，断奶时间对水牛犊牛各种代谢指标和生长模式的影响；（2）阐明水牛犊牛早期断奶、生长代谢物和生长欠佳之间的潜在关系。
本研究共纳入18头不同性别和物种（牛和水牛）的新生犊牛。根据断奶时的年龄将动物分为三组，如下：4.5月龄断奶的奶牛犊牛（n = 8）、3.5月龄断奶的水牛犊牛（n = 6，早期断奶）和5.5月龄断奶的水牛犊牛（n = 4，晚期断奶）。在研究期间及断奶前后（断奶前2周和断奶后2周），每月测量一次形态特征、生长代谢物和激素水平。
结果表明，奶牛犊牛和晚期断奶的水牛犊牛的生长模式呈线性显著增加趋势，而早期断奶的水牛犊牛断奶后体重急剧下降。到研究结束时，早期断奶的水牛犊牛体重增加最少（生长欠佳）。形态特征与各种生长代谢物和激素指标之间存在正相关。与其他动物相比，早期断奶的水牛犊牛生长激素（胰岛素样生长因子-1 [IGF-1] 和胰岛素）及其他代谢物浓度显著降低（p<0.05）。应激指标（皮质醇水平和中性粒细胞与淋巴细胞比率）与生长速率之间无关联。
早期断奶的水牛犊牛生长速率欠佳较为常见，这归因于生长代谢物血液水平较低，尤其是IGF-1。此外，IGF-1浓度与生长形态特征之间的强正相关表明，IGF-1是评估个体犊牛代谢状态的可靠指标。
