Bjerg Bjarne, Brandt Pia, Pedersen Poul, Zhang Guoqiang
Department of Veterinary and Animal Sciences, University of Copenhagen, Grønnegårdsvej 2, 1870, Frederiksberg C, Copenhagen, Denmark.
Department of Veterinary and Animal Sciences, University of Copenhagen, Grønnegårdsvej 2, 1870, Frederiksberg C, Copenhagen, Denmark.
J Therm Biol. 2020 Dec;94:102758. doi: 10.1016/j.jtherbio.2020.102758. Epub 2020 Oct 11.
There is a comprehensive body of literature on how increased air temperature affects the physiology, production and behaviour of sows, while very few studies consider the thermal effects of air humidity and air velocity. This review summarises studies that have investigated effects of air temperature by reviewing published literature in which sows were exposed to at least two different levels of air temperature ranging from 15 °C to 39 °C. Increased rectal temperature was investigated in the majority of the studies (26) and on average, the rectal temperature increased by 0.099 °C per °C increased air temperature above 25 °C. The increase was smaller at lower air temperatures, and it was suggested that rectal temperature is practically unaffected by air temperatures in the range of 15 °C-21 °C. This review elucidates how air temperature also affects performance indicators such as respiration rate, vaginal temperature, skin temperature, feed intake, milk yield, body weight loss during lactation, mortality, litter daily weight gain during lactation and sow behaviour. One study reported how respiration rate, rectal temperature, vaginal temperature and skin temperature were affected by both air temperature and air humidity, and the results suggest that the relative significance of air temperature and humidity may be similar for sows and finishing pigs (e.g. an increase of 40% relative humidity at an air temperature of 30 °C has a similar effect as a 1.9 °C increase in temperature). Studies on mitigation methods against the effects of high temperature and humidity such as snout cooling, drip cooling and floor cooling were reviewed to extract knowledge related to the effects of air velocity, temperatures of surrounding surfaces and the opportunity for sows to moisten their skin.
关于气温升高如何影响母猪的生理、生产和行为，已有大量的文献资料，但很少有研究考虑空气湿度和风速的热效应。本综述通过回顾已发表的文献来总结研究气温影响的相关研究，这些文献中母猪暴露于至少两种不同水平的气温下，范围从15℃到39℃。大多数研究（26项）调查了直肠温度的升高情况，平均而言，当气温高于25℃时，每升高1℃，直肠温度升高0.099℃。在较低气温下升高幅度较小，有人认为在15℃-21℃范围内，直肠温度实际上不受气温影响。本综述阐明了气温如何影响呼吸频率、阴道温度、皮肤温度、采食量、产奶量、哺乳期体重损失、死亡率、哺乳期仔猪日增重和母猪行为等性能指标。一项研究报告了呼吸频率、直肠温度、阴道温度和皮肤温度如何受到气温和空气湿度的影响，结果表明，气温和湿度的相对重要性对母猪和育肥猪可能相似（例如，在30℃的气温下，相对湿度增加40%与气温升高1.9℃有类似的效果）。对针对高温和高湿影响的缓解方法的研究进行了综述，如口鼻降温、滴水降温和平板降温，以提取与风速、周围表面温度以及母猪湿润皮肤机会的影响相关的知识。
