Effect Of Parity, Lactation Month, Sampling Time On Milk Fat Content Of Ili Horse

This experiment takes 30 Yilihorses of Zhaosu Horse Farm as the research object. Study the effect of parity(4, 7, 8), lactation month(8, 9, 10), sampling time(11,13,16 h) on milk fat content of Ili horse. Ili horse start lactation in early July, the first month don't milking, it used to lactation pony. This study began in August, according to the physiological characteristics of Yilihorse breast. We collection the milk yield 4times everyday in lactation, and use the cylinder weighing, each time we collection milk samples of 50 mL.Then measure the milk fat percentage by milk composition, and analysis the factors which influencing on milk fat percentage. It is to achieve optimal variable level by response surface analysis of Design-Expert8.0.5. Design of 3 factors and 3 levels of tests, the last is establishment of mathematical model.The results showed that the interaction of different parity and milking period, lactation and parity of butterfat rate has a significant effect(P<0.05). Secondary multivariate regression model is:Y=0.85+0.026X1+0.073X2-0.044X3+0.075X1X2-0.093X1X3+0.01X2X3-0.11X12-0.014X22-0.016X32. P<0.01,which indicates that model is highly significant; the adjusted determine coefficients R2 adj is 0.7649 in model.It is shows that the model is able to explain 76.49% response value changes can be used this model on milk fat rate analysis and prediction. The milk fat percentage of the best level is 1.01% when the horse in eighth parity sampling time points of 16, lactation month is August. It can provide basic reference for the selection of milk quality.