Odensten M O, Holtenius K, Waller K Persson
Department of Animal Nutrition and Management, Swedish University of Agricultural Sciences, SE-753 23 Uppsala, Sweden.
J Dairy Sci. 2007 Feb;90(2):898-907. doi: 10.3168/jds.S0022-0302(07)71573-4.
With increasing milk production and short calving intervals, high daily milk yields at dry-off are rather common, making the dry-off procedure difficult and increasing the risk for health problems during the dry-off period. The objective of the following study was to compare the effects of 2 dry-off protocols, using different nutrient supplies, on health, as measured by clinical findings, intramammary infections, milk somatic cell count, and plasma concentrations of cortisol, serum amyloid A, haptoglobin, and Mg, in dairy cows. Twenty-one primi- and multiparous dairy cows were randomly assigned to 2 different feeding treatments. One group was fed ad libitum straw (straw), whereas the other group was fed 4 kg of DM silage daily and ad libitum straw (silage) during dry-off (i.e., for 5 d). All cows were milked in the morning of d 3 and 5 during this period. At the start of dry-off (d 0), the average daily milk yield was 17.1 +/- 0.8 kg. The plasma cortisol concentration increased during dry-off only in cows fed straw. There was no significant effect of treatment on plasma serum amyloid A, but the concentration increased during dry-off in both groups. The plasma Mg concentration decreased during dry-off, and the values tended to be lower in the straw group. The milk somatic cell count increased in both groups during dry-off but did not differ between groups. In both groups the heart rate decreased at dry-off, but the decrease was more pronounced in the straw group. Overall, this study (together with a previous report) shows that the common dry-off procedure of feeding straw only may give rise to metabolic disturbances. However, this might be avoided without any apparent negative effects on udder health if a limited amount of silage is added during dry-off.
随着牛奶产量的增加和产犊间隔的缩短，干奶期的日高奶产量相当常见，这使得干奶程序变得困难，并增加了干奶期健康问题的风险。以下研究的目的是比较两种不同营养供应的干奶方案对奶牛健康的影响，通过临床检查结果、乳房内感染、乳体细胞计数以及皮质醇、血清淀粉样蛋白A、触珠蛋白和镁的血浆浓度来衡量。21头初产和经产奶牛被随机分配到两种不同的饲养处理组。一组自由采食秸秆（秸秆组），而另一组在干奶期（即5天）每天饲喂4千克干物质青贮料并自由采食秸秆（青贮料组）。在此期间，所有奶牛在第3天和第5天上午挤奶。干奶开始时（第0天），平均日奶产量为17.1±0.8千克。仅在饲喂秸秆的奶牛中，干奶期血浆皮质醇浓度升高。处理对血浆血清淀粉样蛋白A没有显著影响，但两组在干奶期浓度均升高。干奶期血浆镁浓度降低，秸秆组的值往往更低。两组在干奶期乳体细胞计数均增加，但组间无差异。两组在干奶期心率均下降，但秸秆组下降更明显。总体而言，本研究（连同之前的一份报告）表明，仅饲喂秸秆这种常见的干奶程序可能会导致代谢紊乱。然而，如果在干奶期添加有限量的青贮料，可能避免这种情况，且对乳房健康没有任何明显的负面影响。
