Dias Kamila, Garcia Sergio, Islam Mohammed Rafiq, Clark Cameron
Animal Science Department, Santa Catarina State University (UDESC), Lages, SC, Brazil.
Dairy Science Group, School of Life and Environmental Sciences University of Sydney, Camden, NSW 2570, Australia.
Animals (Basel). 2019 Feb 14;9(2):60. doi: 10.3390/ani9020060.
(1) Background: Pasture varies in its chemical composition from the top of the sward to the base and cattle prefer to eat the leaf fraction. In pasture-based dairy systems, cattle predominantly walk back to pasture voluntarily after each milking, with the first cattle arriving to pasture hours before the last. Here we study the impact of pasture composition according to milking order on milk yield and milk composition for dairy cattle offered grazed ryegrass pasture. (2) Methods: In the first experiment, individual cow milk yield data were recorded on six farms over 8 months. The herd was divided into groups of 50 cows for analysis according to milking order. In the second experiment, the impact of milking order on milk composition and pasture composition accessed was determined in addition to milk yield on three farms. (3) Results: After accounting for age and stage of lactation effects, cattle milked first in experiment 1 produced, on average, 4.5 L/cow/day (+18%; range 14 to 29%) more than cattle milked last. In experiment 2, dairy cattle milked first (first 50 cows) in farm 1 had greater milk, protein, and solids non-fat (SNF) yield; and less lactose content than those milked last (last 50 cows). In farm 2, dairy cattle milked first had greater milk yield, SNF yield, lactose yield, and fat yield; but less protein and SNF content than cattle milked last. In farm 3, cattle milked first produced milk with greater fat and protein content than cattle milked last. In line with these differences in milk yield and composition, the composition of pasture across vertical strata differed, particularly for crude protein (CP) and acid detergent fiber (ADF) content. Conclusion: This work highlights the opportunity to increase herd nutrient use efficiency for improved milk production through strategic pasture allowance and supplementation strategies.
(1) 背景：从草层顶部到底部，牧草的化学成分各不相同，而奶牛更喜欢采食叶片部分。在以牧场为基础的奶牛养殖系统中，奶牛每次挤奶后主要是自愿返回牧场，第一批奶牛比最后一批提前数小时到达牧场。在此，我们研究了按挤奶顺序划分的牧场组成对采食黑麦草牧场的奶牛产奶量和奶成分的影响。(2) 方法：在第一个实验中，在6个农场记录了8个月内每头奶牛的产奶量数据。根据挤奶顺序将牛群分成每组50头奶牛进行分析。在第二个实验中，除了在3个农场测定产奶量外，还确定了挤奶顺序对奶成分和所采食的牧场组成的影响。(3) 结果：在考虑年龄和泌乳阶段的影响后，实验1中第一批挤奶的奶牛平均比最后一批挤奶的奶牛每天多产奶4.5升/头（+18%；范围为14%至29%）。在实验2中，农场1中第一批挤奶的奶牛（前50头）产奶量、蛋白质产量和非脂固形物（SNF）产量更高；乳糖含量低于最后一批挤奶的奶牛（后50头）。在农场2中，第一批挤奶的奶牛产奶量、SNF产量、乳糖产量和脂肪产量更高；但蛋白质和SNF含量低于最后一批挤奶的奶牛。在农场3中，第一批挤奶的奶牛所产牛奶的脂肪和蛋白质含量高于最后一批挤奶的奶牛。与这些产奶量和奶成分的差异一致，垂直分层的牧场组成也不同，特别是粗蛋白（CP）和酸性洗涤纤维（ADF）含量。结论：这项工作突出了通过战略性的牧场配额和补充策略提高牛群养分利用效率以改善牛奶生产的机会。
