Lambertz C, Sanker C, Gauly M
Department of Animal Sciences, Georg-August University, Albrecht-Thaer-Weg 3, 37075 Göttingen, Germany.
Department of Animal Sciences, Georg-August University, Albrecht-Thaer-Weg 3, 37075 Göttingen, Germany.
J Dairy Sci. 2014;97(1):319-29. doi: 10.3168/jds.2013-7217. Epub 2013 Nov 13.
The objective of this study was to compare the effect of the temperature-humidity index (THI) on milk production traits and somatic cell score (SCS) of dairy cows raised in 4 different housing systems: (1) warm loose housing with access to grazing (WG), (2) warm loose housing without access to grazing (WI), (3) cold loose housing with access to grazing (CG), and (4) cold loose housing without access to grazing (CI). For each of the 4 housing systems, 5 farms with a herd size of 70 to 200 lactating cows in Lower Saxony, Germany, were studied. Ambient temperature and relative humidity were recorded hourly in each barn to calculate THI. Milk production data included 21,546 test-day records for milk, fat, and protein yield, and SCS. These data were associated with the average THI of the 3 d preceding the respective measurement, which was divided into 6 classes (<45, ≥45 to <50, ≥50 to <55, ≥55 to <60, ≥60 to <65, and ≥65). Furthermore, bulk milk samples including the fat and protein percentage, and SCS taken 4 to 6 times per month were associated with the average and maximum THI of the 3 d before sampling. Data were recorded from April 2010 to March 2011. In each of the housing systems, monthly THI values above 60, indicating heat stress, were recorded between June and September, with higher values in WI and WG. In all systems, fat-corrected milk, fat, and protein yields of the test-day records decreased in tendency from 60 ≤ THI<65 to THI >65. In WI and CI, values for SCS were greater in the class THI > 65 than in 60 ≤ THI<65, whereas no difference between any of the THI classes was found in WG and CG. The fat and protein percentage of the bulk milk samples decreased with increasing 3-d maximum THI in all 4 systems, whereas the SCS increased with increasing 3-d average THI. In conclusion, negative effects of heat stress conditions under a temperate climate on milk production traits and SCS were found, although a housing system being superior to the other systems in altering heat stress effects was not identified.
本研究的目的是比较温湿度指数（THI）对饲养在4种不同畜舍系统中的奶牛产奶性状和体细胞评分（SCS）的影响：（1）可放牧的温暖散养舍（WG），（2）不可放牧的温暖散养舍（WI），（3）可放牧的寒冷散养舍（CG），以及（4）不可放牧的寒冷散养舍（CI）。对于这4种畜舍系统中的每一种，研究了德国下萨克森州5个存栏量为70至200头泌乳奶牛的农场。每间牛舍每小时记录环境温度和相对湿度以计算THI。产奶数据包括21,546条关于牛奶、脂肪和蛋白质产量以及SCS的测定日记录。这些数据与相应测量前3天的平均THI相关，该平均THI被分为6类（<45、≥45至<50、≥50至<55、≥55至<60、≥60至<65以及≥65）。此外，每月采集4至6次的原料奶样本（包括脂肪和蛋白质百分比以及SCS）与采样前3天的平均THI和最高THI相关。数据记录时间为2010年4月至2011年3月。在每种畜舍系统中，6月至9月期间记录到每月THI值高于60（表明存在热应激），WI和WG中的值更高。在所有系统中，测定日记录的乳脂校正乳、脂肪和蛋白质产量从60≤THI<65到THI>65有下降趋势。在WI和CI中，THI>65组的SCS值高于60≤THI<65组，而在WG和CG中，任何THI类别之间均未发现差异。在所有4个系统中，原料奶样本的脂肪和蛋白质百分比随3天最高THI的升高而降低，而SCS随3天平均THI的升高而增加。总之，尽管未发现一种畜舍系统在改变热应激影响方面优于其他系统，但发现了温带气候下热应激条件对产奶性状和SCS的负面影响。
