Effect of Air flow on Pig growth

The effect of air flow on pig body is mainly to affect the heat dissipation of pig body. Under general environmental conditions, as long as there is air flow, it can promote the convection and evaporation heat dissipation of the body. When the ambient temperature is lower than the suitable temperature limit of the pig, the heat dissipation of the pig is increased due to the action of air flow, which makes the pig feel cold. at this time, more energy is needed to maintain the body temperature. On the contrary, when the ambient temperature is higher than the upper limit of the suitable temperature of pigs, because the air flow contributes to the heat dissipation of pigs, and the heat dissipation is more when the air flow is large, increasing the wind speed can obviously improve the warm environment of pigs and alleviate the adverse effects of heat stress on pigs.

Besides the speed of air flow, the temperature of air flow is also a very important factor in the effect of air flow on heat dissipation of pigs. the effect of heat dissipation decreases with the increase of air temperature. When the air temperature is equal to the skin temperature of the pig, the effect of convection heat disappears; when the air temperature is higher than the skin temperature, the body gets heat through convection; the low and humid air flow can significantly increase the heat dissipation, and the pig feels more cold, which may cause frostbite and freeze to death. The air flow always acts in conjunction with temperature and humidity on the body of pigs, so that the degree of cold and heat stress can be alleviated or intensified.

It is reported that when the ambient temperature in the house is 12 degrees Celsius, the air flow speed increases from 0.1 m / s to 0.26 m / s, and the heat dissipation of pigs weighing 25-30 kg will increase by about 10%. For 2 kg piglets, when the airflow velocity increased from 0.1 m / s to 0.56 m / s, the ambient temperature decreased by 4 degrees Celsius. Some experts believe that for piglets, the air flow rate should not exceed 0.3 m / s at all ambient temperatures, otherwise it will cause the piglets to get cold and increase diseases (such as pneumonia). Of course, when the ambient temperature is too high, properly increasing the air flow speed will help the piglets to cool down. However, the cooling airflow speed in all kinds of piggery should not be too high, and the friction of excessive airflow will make pigs feel uncomfortable.

In winter, from the point of view of warmth, the flow velocity can be lower than the median value of the table. Under the condition of high temperature in summer, the flow velocity can be higher than the median value of the table to facilitate the heat dissipation of pigs. However, it is reported that if the ground is wet and the skin of a pig is wet on the ground at a high temperature of 48 degrees Celsius, the wind speed increases from 0.1m / s to 0.9m / s, and the rising body temperature can be reduced by about 2 ℃ in 30 minutes. When the ground and pig skin are dry, even increasing the wind speed has no effect. It can be seen that in summer, for pigs without sweat glands, there is a certain limit to the effect of simply increasing air flow velocity to help pigs dissipate heat. It must be supplemented by spray in order to give full play to the cooling effect of air flow.