Abstract：
A systematic review and meta-analysis were conducted to assess the impact of recombinant bovine somatotropin (rbST) on lactation performance, feed efficiency, and blood metabolites in dairy cows. In the systematic review, articles were selected based on the following criteria: (1) Data focusing on the influence of bovine somatotropin doses on milk production; (2) Submission of original data; (3) Articles published in journals; and (4) Articles in English or Portuguese. The analysis of variance was used with a completely randomized design and mixed models methodology. Polynomial regression was applied to significant fixed effects (rbST dose). The use of rbST resulted in increased milk yield and 4% fat-corrected milk yield, while fat, protein, and lactose contents remained unaffected. Dry matter and metabolizable energy intakes, as well as milk/feed efficiency, exhibited a linear increase, but body condition score (BCS) was negatively impacted. The administration of rbST led to higher blood concentrations of triglycerides and insulin. Cows treated with rbST showed a 23% increase in non-esterified fatty acid (NEFA) concentrations compared to non-treated cows. Additionally, growth factors IGF-1 and IGF-2 displayed a linear increase with rbST treatment. In summary, rbST administration increased milk yield and fat-corrected milk yield without affecting milk components. However, despite increasing intake, it resulted in BCS losses and alterations in blood parameters such as NEFA, IGF-1, and IGF-2.
摘要：
进行了系统评价和荟萃分析，以评估重组牛生长激素（rbST）对泌乳性能的影响。饲料效率，和奶牛的血液代谢产物。在系统审查中，根据以下标准选择文章：（1）关注牛生长激素剂量对牛奶产量影响的数据；（2）原始数据的提交；（3）在期刊上发表的文章；（4）英文或葡萄牙文文章。方差分析与完全随机设计和混合模型方法一起使用。多项式回归应用于显著的固定效应(rbST剂量)。rbST的使用导致牛奶产量增加和4％的脂肪校正牛奶产量，虽然肥胖，蛋白质，乳糖含量未受影响。干物质和代谢能量摄入量，以及牛奶/饲料效率，表现出线性增加，但身体状况评分（BCS）受到负面影响。rbST的施用导致更高的血液中甘油三酯和胰岛素浓度。与未处理的奶牛相比,用rbST处理的奶牛显示出非酯化脂肪酸(NEFA)浓度增加23%。此外,生长因子IGF-1和IGF-2在rbST处理下呈线性增加。总之,rbST给药可增加牛奶产量和脂肪校正的牛奶产量，而不会影响牛奶成分。然而,尽管摄入量增加，它导致BCS损失和血液参数的改变，如NEFA，IGF-1和IGF-2。
