Study On The Effect Of Yili Horse Polynomial Fitting Lactation Curve Analysis And Breeding Values Estimation Of Lactation Performance

The subject was sampled from Yili horse in Zhaosu field, and collected the mares lactation records which were 32 Yili stallions’ offspring, and measured the mike production and milk compositions(milk fat, milk protein,lactose, nonfat solid and somatic cell count). Used mare’s milk production and milk compositions of fitting to drew out the lactation curve by six times polynomial regression model, and provided a basic basis for estimating the Yili mare’s milk production; Used animal model Blup method to estimate the breeding value of Yili stallion. To provide theoretical basis for the stud stock value evaluation in Zhaosu field, and to offer the preliminary basis and necessary support for specialization with milk horses breed. The results of this subject as follow:1. Effects of six times polynomial regression model fitting on milk yield and milk composition of Yili horseUsed six times polynomial regression model, and fitted curve different kinds of male offspring for milk production and milk composition(milk fat rate, milk protein rate, lactose rate, nonfat solid and Somatic cell count), and to guided the local horse farm production practice for improving the milk production. The subject found that: the fitting degree(R2)of the milk yield and milk composition of 32 Yili stallions’ offspring was 0.90. The fitting degree(R2)of milk fat percentage was lowest, 0.85. The fitting degree(R2)of milk protein, milk sugar rate, non-fat solid and.somatic cell count were over 0.90. This was show that six times polynomial regression model for offspring mare lactation curve fitting effect is good. It showed that there was an good effect of Polynomial regression model six generations on fitting effect of lactating mares.2. The study of milk performance genetic parameters and breeding value estimation of Yili horseUsed SAS 8.1 statistical analysis software GLM procedure, and the model Blup to estimate breeding values of Yili stallion(such as milk fat, milk protein, lactose rate, non-fat solids and somatic cell count) as well as the genetic parameters and breeding values of offspring by MTDFREML2000 f software. The heritability of Yili horse in 150 days milk yield, milk fat, milk protein, lactose rate, non-fat solids, somatic cell count are 0.34,0.12,0.26,0.14,0.20,0.27; the highest milk breeding value, the highest breeding value of milk fat, the highest breeding value of lactose rate and the highest breeding values of body cells among these samples were 18 th stallions; the highest breeding values for milk protein percentage was 1st stallion; the highest breeding values for lactose was 18 th stallions;the highest integrated breeding value of six horses stallions was 18 th stallion for 48.936; followed by the 2nd stallions, integrated breeding value was 42.068; integrated breeding value was the lowest on the 1st stallion, only 17.335. This study made the preliminary work of Yili Zhaosu field Stallions in lactation performance germplasm assessment.