Effects Of Thermal Environment On Growth And Behavior Of Pigs Under Different Breeding Modes In Northern Area

At present,the density of pigs is too high,which leads to the serious heat accumulation in the piggery.Thermal environment has become one of the problems that farmers pay attention to.At present,the research on the thermal environment of pig breeding is mainly concentrated in the south.However,in summer,the high temperature and high humidity environment in the north will also affect the normal growth and development of pigs.Therefore,in order to improve the efficiency and economic benefits of pig breeding,piggery environmental regulation and control of the northern area provided a reference for the design,at the same time,combing the current pig-breeding digital characterization of chaotic phenomenon,this paper studies a large amount of thermal environment at home and abroad about the pig growth performance and the ability to reproduce only influence of the literature,based on this,the effects of summer thermal environment on the growth and behavior of piglets in northern China were explored through experiments.The main work is as follows:（1）The domestic and foreign literature on the effects of thermal environment on growth performance and reproductive capacity of pigs from 2000 to 2020 were reviewed.In view of the present situation of the confusion of digital indicators of pig breeding,the data of growth performance of pigs and reproductive performance of sows in the literature showed that the feed utilization rate of finishing pigs was the highest when the temperature was 18.5℃-28.4℃and the relative humidity was 67%-84%,and the ratio of feed to gain was maintained at 2.2-2.86.When the temperature was between 19℃and 25℃and the relative humidity was between45%and 85%,the weight of weaned piglets was the maximum,which maintained at 6.32 kg to6.9 kg.（2）The effects of thermal environment on the growth of piglets under different breeding conditions were explored through experiments.The results showed that temperature and humidity had significant effects on crude protein digestibility and ether extract digestibility of piglets（P<0.05）,and the ratio of feed to gain of piglets in indoor culture environment was low.Considering the synergistic effect of other environmental factors except temperature and humidity in thermal environment,the optimal range of indoor growth index thermal environmental parameters of piglets under experimental conditions was determined as follows:Temperature 22.5℃-25.5℃,humidity 67.5%-71.5%,CO₂concentration 885mg/m³-1115 mg/m³,the optimal range of outdoor growth index thermal environmental parameters of piglets:Temperature 23.5℃-26.5℃,relative humidity 77.5%-82.5%,solar radiation 1350 W/m²-1650 W/m²,wind speed 1.2m/s-1.8m/s.（3）The effects of thermal environment on the behavior of piglets under different breeding conditions were explored through experiments.During the experiment,the sleeping time of indoor piglets was 0:00-6:00,12:00-16:00 and 22:00-24:00,while the sleeping time of outdoor piglets was 4:00-8:00,14:00-16:00 and 20:00-22:00.The sleeping time of piglets in outdoor piggery is characterized by long interval and short duration.The daily behavior comfort of piglets was evaluated by weighted analysis method.The comfort temperature range of indoor piglets was 20.7℃-23.5℃and humidity was 67%-72%,while the comfort temperature range of outdoor piglets was 22.1℃-25.2℃and humidity was 74%-79%.In this paper,the phenomenon of confusion in digital representation of current pig breeding was sorted out through literature study.Meanwhile,the growth and behavior of piglets in indoor and outdoor breeding environments in northern China in summer were explored through experiments,and the optimal range of thermal environmental parameters for growth and behavior of piglets in this region was determined.It provides a reference for the design of environmental regulation scheme of summer piggery in northern China,so as to improve the efficiency and economic benefit of pig breeding.