Departamento de Ciencia y Tecnología de la Leche, Facultad de Veterinaria, Universidad de la República, Paysandú, Uruguay.
Departamento de Salud en los Sistemas Pecuarios, Facultad de Veterinaria, Universidad de la República, Paysandú, Uruguay.
Anim Sci J. 2019 Nov;90(11):1484-1494. doi: 10.1111/asj.13288. Epub 2019 Sep 9.
This study aimed to determine if a diet change from a mixed system to a confinement system affects the milk production and composition, behavior and blood biochemistry of dairy cows. Cows were assigned randomly to one of the two treatments: cows fed with TMR (total-mixed-ration) (confined) throughout the period group fed TMR (GTMR, n = 15) and cows that changed their diet from pasture plus TMR to exclusive TMR at 70 ± 14 DIM (GCHD, n = 15). GTMR cows produced more milk and greater lactose and protein yield before the change of diet than GCHD cows (p ≤ .01), but these differences disappeared after the change. GCHD cows decreased the frequency of rumination and lying from before to after the change (p ≤ .03), but in GTMR cows no changes were observed. After diet change, GCHD cows had lower frequency of rumination and lying than GTMR cows (p ≤ .02). Before the change, GCHD cows had greater NEFA (non esterified fatty acids) concentrations than GTMR cows (p = .002). Abrupt change from a mixed system to a confined system was favorable on blood biochemical and milk variables of dairy cows. However, in relation to behavior, the cows expressed difficulties to adapt quickly to the abrupt change of system.
本研究旨在确定从混合系统改为限制系统的饮食变化是否会影响奶牛的牛奶产量和组成、行为和血液生化特性。将奶牛随机分配到两种处理方式之一：在整个时期都用 TMR（全混合日粮）喂养的奶牛（限制组），以及从放牧加 TMR 改为仅用 TMR 喂养的奶牛（GCHD 组，n = 15）。与 GCHD 组相比，GTMR 组奶牛在改变饮食前的产奶量、乳糖和蛋白质产量更高（p ≤.01），但这些差异在改变饮食后消失。GCHD 组奶牛在改变饮食前后，反刍和躺卧的频率降低（p ≤.03），但 GTMR 组奶牛没有观察到这些变化。改变饮食后，GCHD 组奶牛的反刍和躺卧频率低于 GTMR 组（p ≤.02）。在改变饮食前，GCHD 组奶牛的非酯化脂肪酸（NEFA）浓度高于 GTMR 组（p =.002）。从混合系统到限制系统的突然改变有利于奶牛的血液生化和牛奶变量。然而，就行为而言，奶牛表现出难以迅速适应系统的突然改变。
