Effect of the duration of high air temperature on cow’s milking performance in moderate climate conditions
Effect of the duration of high air temperature on cow’s milking performance in moderate climate conditions
复制标题
温和气候条件下高温持续时间对奶牛挤奶性能的影响
DOI：
10.1515/aoas-2017-0017
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发表时间：
2018
期刊：
影响因子：
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通讯作者：
D. Godyń
中科院分区：
文献类型：
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作者：
P. Herbut;S. Angrecka;D. Godyń
摘要本研究的主要目的是确定夏季温和气候条件下空气热条件变化对奶牛挤奶性能的影响。分析涵盖了2012-2013年夏季（6 - 9月）和较短的几天时间段，其特征是气温升高或高气温的时间以及挤奶性能的下降和增加。这项研究是在一个自由栏牛舍进行的荷斯坦黑白花奶牛。研究表明，随着夏季气温的升高，高产奶牛的热中性温度逐渐降低。产奶量的下降已经开始在空气温度等于20°C，也取决于奶牛的敏感性。7、8月份高温日数较多，导致9月份奶牛对热环境恶化的反应较快，产奶性能的下降几乎与气温变化同时发生，产奶量在3- 4d后恢复（r=-0.84，P <0.04）。还确定了导致产奶量下降的各个温度范围内的持续时间百分比。6月和7月上旬，温度高于20°C时有90%的产奶量下降，高于25°C时有45%的产奶量下降（r=-0.89，P <0.02）。在9月份，气温高于20°C时，这一比例仅为30%（r=-0.91，P <0.01）。
Abstract The main aim of the presented investigation was to determine the effect of the air thermal conditions variability on cow’s milking performance in summer in a moderate climate. The analyses covered the summer months of 2012-2013 (June-September) and shorter, several-day periods characterized by the times of elevated or high air temperatures and by the declines and increases in milking performance. The research was conducted in a free stall barn for Holstein-Friesian cows. The study showed that the thermoneutral temperature for high yielding cows decreases gradually with the registered increasingly warmer summer periods. The decreases in milk yield already commence at an air temperature equal to 20°C and also depend on the dairy cattle sensitivity. July and August, with a high number of hot days, caused that in September the cows responded faster to a worsening of thermal conditions and the decline in milking performance happened almost simultaneously with the air temperature change, at milking yield recovery after the period of 3-4 d (r=-0.84, P<0.04). The percent duration in the individual temperature ranges which caused a decrease of milk yield was also determined. In June, and at the beginning of July, this was 90% of the time with temperatures above 20°C, and simultaneously 45% above 25°C occurred to milking performance decrease (r=-0.89, P<0.02). In September, this was only 30% of the time with temperatures above 20°C (r=-0.91, P<0.01).