Studies On Relationship Of Early Lactation Traits And Body Image With Lactation Performance Of YiLi Horse In Xinjiang

In this study,60adult mares of Yili horse from Zhaosu farm of Xinjiang were selected as the mainresearch object.1374lactation records,14feet and breasts traits were collected and measured to build thedatabase. The SAS8.1software was taken to compare the fitting effects of three kinds of lactation curvemodels to lactation curve. Then the best fitting model was selected, more accurate correction factor of milkyield for the Xinjiang Yili horse was built to provide scientific basis for accurate evaluation of milk yield ofYili horse. Correlation analysis of maximum daily milk yield and early lactation traits with150milk ofcorrection were studied by SPSS17.0. By establishing the best regression equation, selecting early lactationtraits of predicting milk yield and studying the correlation of body size and150d corrected milk, a linearregression model was built, and a appropriate program which can be used to predict the actual milkproduction of Yili horse was developed, to provide technical support for the early selection of Yili horse.The significant results are as follows:1. Selection of the optimal fitting model of lactation curve and Develop150d correction factorBy comparing the fitting effect of Wood incomplete gamma function model, Nelder inverse polynomialand polynomial regression model (six), the best model, Nelder inverse polynomial was selected. Thismodel is ideal for lactation curve fitting results of4,5parity of Yili horse, fitting degree of0.88,0.93,respectively. On this basis, according to the optimal lactation curve， the150d correction milk of Yili horsewas calculated to provide a basis research on objective assessment of individuals, genetic evaluation andmilk yield of Yili horse;2. The correlation of top daily milk yield and early lactation traits with150d corrected milk yieldA study of the correlation of top daily milk yield and early lactation traits (30,60d milk yield) with150dcorrected milk yield of Yili horse was carried out. The correlation coefficient between different indicatorsby SPSS was caculated, significance tests was also taken, and the optimal regression equation wasestablished, to explore whether the early lactation traits could be the prediction of milk yield traits. In thisstudy, the optimal regression equation result is: y=408.44+43.28X1-0.27X2, established by the top dailymilk yield (X1),30d milk yield (X2) and150d correct milk yield (y). The main factors of affecting milkyield are maximum daily milk yield and30d milk yield;3. Correlation of body size and breast milk production traits with150d correction milk yieldBy studing the correlation of body size and breast milk production traits with150d correction milk yield,the body size traits which affect the milk yield was selected and then the optimal linear regression equationwas built: Y=-537.75+18.58x1+5.72x2-97.59x7-40.51x8+92.38x9-42.65x10-39.30x12-156.94x13+18.12x14.The body size traits can then be used to forecast actual milk production of Yili horse, and provide areference for electing the high milk yield horse in time and specialized variety breeding. At the same time,the optimal linear regression model was packaged as a program in computer, which the body size data wasinput, and then the milk yield would be output. Thus, the computational complexity was reduced, theconvenient and feasible procedure could be provided to herdsmen.