Metabolic conditions of lactating Friesian cows during the hot season in the Po valley. 1. Blood indicators of heat stress
Metabolic conditions of lactating Friesian cows during the hot season in the Po valley. 1. Blood indicators of heat stress
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DOI：
10.1007/s00484-007-0098-3
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发表时间：
2007-12-01
影响因子：
3.2
通讯作者：
Stefanini, Luigi
中科院分区：
文献类型：
--
作者：
Abeni, Fabio;Calamari, Luigi;Stefanini, Luigi
在连续两个夏季，分别对21头和18头奶牛进行血液参数和产奶量监测，评估其在泌乳期不同阶段热应激水平的变化。在这两年中，根据奶牛在夏初的泌乳阶段（早、中、晚）进行监测。通过温度湿度指数来描述气候条件。监测奶牛的呼吸频率、直肠温度、血液代谢产物和酶以及产奶量。在第一年，发现了两个更热的时期，第二个时期的情况更严重，奶牛的直肠温度高于40摄氏度。在第二年，只发现了一个更热的时期，热应激与第一年的第一时期相当。热期产奶量下降；在这两年中，奶牛在泌乳中期的产奶量下降幅度较大。两年中较热时期的血糖下降都很明显。血浆胆固醇在这些时期也有所下降。两年中较热时期血浆ALP活性的降低证实了这种酶作为一种快速可靠的热应激血液标志物的作用。
In two consecutive summers, 21 and 18 cows, respectively, were monitored for blood parameters and milk yield, to assess their variation according to the level of heat stress at different stages of lactation. During both years, the cows were monitored according to their lactation phase (early, mid-, and late) at the beginning of the summer. Climatic conditions were described through the temperature humidity index. Cows were monitored for breathing rate, rectal temperature, blood metabolites and enzymes, and milk yield. In the first year, two hotter periods were identified, with more severe conditions in the second one, when cows had rectal temperatures higher than 40 degrees C. In the second year, only one hotter period was identified, with a heat stress comparable to that of the first period of the first year. Milk yield declined during the hotter period; in both years, a higher reduction in milk yield was recorded for cows in the mid-stage of lactation. The decrease in plasma glucose during the hotter period was evident in both years. Plasma cholesterol also decreased in those periods. The reduction in plasma ALP activity in the hotter period of both years confirmed the role of this enzyme as a quick and reliable heat-stress blood marker.