SCR Engineers Ltd., POB 13564, 18 Hamelacha St., Netanya, 4250553, Israel.
Agricultural Research Organization, Institute of Animal Science, Beit Dagan, 5020000, Israel.
J Dairy Sci. 2019 Apr;102(4):3480-3486. doi: 10.3168/jds.2018-15186. Epub 2019 Feb 7.
Monitoring thermal status using a reliable, practical method is essential for proper cattle management during periods of high heat load. Our objective was to determine whether accelerometer-based tags, which measure heavy breathing and other behaviors on a minute-by-minute basis, accurately reflect thermal status. We hypothesized that the tags would mirror core body temperature as recorded by continuous intravaginal loggers, and that response to a cooling intervention would also be captured. Data were collected during a 3-d period from 10 late dry and 20 high-producing cows at peak lactation, each fitted with an intravaginal temperature logger and tag attached to a collar. The relationship between vaginal temperature and proportion of cows recorded as breathing heavily averaged over the three 24-h periods was described separately for each group, and during a 1-h block capturing 2 intensive cooling sessions in lactating cows. Finally, the log of the odds of a cow breathing heavily in each minute relative to vaginal temperature in cows before cooling was analyzed using a linear mixed model. The proportion of cows breathing heavily in a group mirrors changes in vaginal temperature in both dry and lactating cows. In contrast to the dry cows, lactating cows suffered from excessive heat load to a much greater degree. Cooling intensively with showers and fans effectively mitigates the effects of excessive heat load, as reflected by response in vaginal temperature and proportion of cows breathing heavily. The probability of heavy breathing increases by approximately 10% for each 0.5°C rise in vaginal temperature above 39.0°C. In conclusion, accelerometer-based technology that automatically records heavy breathing provides a practical means of continuously assessing heat load status of dairy cows, whether lactating or dry, and their response to cooling intervention. This has the potential to optimize both cow and resource management during periods of high heat load.
使用可靠且实用的方法监测热状况对于在高热负荷期间对牛进行适当管理至关重要。我们的目的是确定基于加速度计的标签是否可以准确反映热状况，这些标签可以每分钟测量呼吸沉重和其他行为。我们假设标签将反映连续阴道记录器记录的核心体温，并且还可以捕捉到对冷却干预的反应。在高峰期泌乳的 10 头晚期干牛和 20 头高产牛中，每头牛都佩戴阴道温度记录器和项圈上的标签，连续 3 天收集数据。分别描述了每一组中阴道温度与记录为呼吸沉重的牛的比例之间的关系，以及在捕获泌乳牛 2 次密集冷却的 1 小时块中。最后，使用线性混合模型分析了在冷却前每 1 分钟相对于阴道温度每头牛呼吸沉重的对数的可能性。群体中呼吸沉重的牛的比例反映了干牛和泌乳牛阴道温度的变化。与干牛不同，泌乳牛遭受过度热负荷的程度要大得多。使用淋浴和风扇进行密集冷却可以有效地减轻过度热负荷的影响，这反映在阴道温度和呼吸沉重的牛的比例的反应上。阴道温度每升高 0.5°C，呼吸沉重的概率就会增加约 10%。总之，自动记录呼吸沉重的基于加速度计的技术为连续评估泌乳和干奶牛的热负荷状况及其对冷却干预的反应提供了一种实用方法。这有可能在高热负荷期间优化牛和资源管理。
