Relational Model Between Temperature-Humidity Index (THI) And Feed Intake Or Daily Gain In Growing Pig

Temperature and humidity index (THI) is a combination of temperature and humidity indicators to evaluate the degree of heat. The effects of THI on the growth performance of pigs are concentrated in the respiratory rate, rectal temperature, ear temperature, skin temperature, pulse number, heart rate, body temperature and reproduction and so on. Currently, most of effects are based on temperature, humidity and other single aspect, however, few researches of the effects of THI on feed intake and daily gain of pig is found. The data is collected using "9SC-05 Closed Automatic equipment of selecting swine and feed in the pig"which is reliable and produced by Anhui Putiguo Livestock Technology Co.,Ltd. And systematic analysis and study of temperature, humidity is carried out as well as other environmental factors which effect body weight of growing pigs between 65kg and 95kg. Some meaningful results are obtained. The results provide a reliable protection to shorten the feeding time, improve feed conversion, adjusted feed conversion, select quality breeding, control slaughter time and increase the economic benefits of pig farms.The main contents and the results are as follows:1. This thesis studies the detection of outlier data though Grubbs test and the Dixon test methods. Comparison of the two tests shows the results are exactly same, but because Dixon test is simple, the study uses it to detect the abnormal data, and the average of the accurate sample instead of outliers, and then correct the data one by one for the research.2. This study analyses significant differences of the corresponding THI by analysis of variance. It is found that the difference is significant. The conclusion ensures that models about THI have statistical significance by biological.3. Under the premise that the level of significance is 0.01, the study researches the relationship between environmental temperature and porcine skin temperature by regression analysis. The results show that when the ambient temperature is between 12.5℃and 25.3℃, relative humidity is between 55% and 65%, the relationship between the temperature and the pig's skin temperature is significantly linear. We can use a method to predict and control ambient temperature and the skin temperature. This thesis though analysis of 10 kinds of curve fitting method derives that when the temperature is below 12.5℃, they have no significant function relationship. Low-temperature inflection point interval 12.5℃±0.5℃can help farms to resolve the contradiction between ventilation and warm.4. At the 0.05 level of significance, the study analyzes the weight environmental temperature, humidity, weight and THI impacts on the feed intake of pigs. The results show that the effects are very significant. However, the effect of temperature is not significant by testing the regression coefficients in the combined effect. Therefore, in the comprehensive assessment of temperature and humidity, the humidity plays a very important role.In pig production the humidity must be adjusted to avoid decreased growth performance of pigs caused by the extreme humidity.5. When the wind speed has no effect and at the 0.05 level of significance, this study through a regression analysis method studies the relationships among the daily gain feed intake and THI, and obtains two significant regression models. Regression equations can be used to predict the daily gain or feed intake and control the THI. These models can guide the actual production that how to control the THI. For example, if we hope the pig's weight increase about 500-900g after a day, the THI should try to keep between 60 and 67.6. At the 0.05 level of significance, the thesis studies the combined effects of the pig's daily feed intake and THI on daily gain. The results show that the combined effect is very significant and a binary regression equation can be used to predict or control the daily gain, THI and feed intake. We can predict the daily gain by THI and daily feed intake, at the same time we can control the daily feed intake and the THI according to the ideal daily gain. This model significantly reduces feeding time, and control the actual production of slaughter time.