Fitting Study On Lactation Curve Of Xinjiang Donkey

In this study,the 3rd,4th,and 5th parity Xinjiang donkeys in the donkey farm in Yuepuhu County,Kashgar,Xinjiang were used as the research objects.The optimal lactation curve fitting model and the 20-week corrected milk yield regression equation were used to evaluate the performance of Xinjiang donkeys.Lactation performance.3840 pieces of lactation data collected in 10 months were sorted and analyzed to establish a lactation statistics table,and SAS 9.4 software was used to compare the four models of Wood model,inverse polynomial model,six-degree polynomial model and cubic model to fit Xinjiang donkeys at 8 o’clock and 20 o’clock respectively.And the lactation curve of the whole lactation period,analyze the parameter value and fit of each fitting model,and use SPSS 26.0 to analyze the correlation between the 8 o’clock,20 o’clock and the highest daily milk production and the 20-week corrected milk production,and establish the correlation Sex regression equation.The results show that the hexagonal polynomial regression model is the best fitting model for Xinjiang Donkey at 8:00,20:00 and the full lactation period.Using 8:00,20:00and the highest daily milk production can accurately predict the milk production in the full lactation period.It can objectively evaluate the lactation performance of Xinjiang donkeys,improve the accuracy of breed selection,and provide reference and scientific support for the lactation data of Xinjiang donkeys.The results of this study are as follows:1.The variation law of milk production in the morning and evening of Xinjiang donkeys in a single dayThrough the fitting and difference analysis of the 3rd,4th and 5th parity of Xinjiang donkey morning and evening lactation curves,it is found that the sixth-order polynomial regression model is the best fitting model of Xinjiang donkey at 8:00 and 20:00.The fitting degree at parity 8 was0.9257,0.9567,0.9666,and the fitting degree at parity 20 was 0.9641,0.9392,and 0.9343,respectively;the milk production of Xinjiang donkey at 8 was higher than at 20 for three parities;the fifth parity The milk yield at 8:00 and 20:00 was significantly different from that of the 3rd and4th parity（P<0.05）,and the milk yield was significantly lower than that of the other two parities.The above results show that the milk production of Xinjiang donkeys has a special regularity at 8:00and 20:00 in a single day.2.The variation law of daily milk production of Xinjiang donkeys during the whole lactation period Through the fitting and difference analysis of the milk production and lactation curves of the 3rd,4th,and 5th parity Xinjiang donkeys during the whole lactation period,it is found that the sixth-order polynomial regression model is the best fitting model for the whole lactation period of Xinjiang donkeys.The fitting degree of parity and parity 5 were 0.9585,0.9641,and 0.9570,respectively;the average daily milk yield of Xinjiang donkeys in the third parity was significantly higher than that of parity 4 and parity 4 and 5 in the pre-lactation and mid-term lactation period.The average daily milk production of the parity was significantly higher（P<0.01）than that of the third parity;the 20-week corrected cumulative milk production of Xinjiang donkeys in the third,fourth,and fifth parity were 346.46,358.63,and 287.42,respectively,which were different from the actual20-week cumulative milk production.The difference analysis results of milk production were not significant（P>0.05）.3.Correlation analysis between the highest daily production and lactation traits of Xinjiang donkeys at different times and 20-week corrected milk productionThrough the correlation analysis between the milk production at 8:00,20:00 and the 20-week corrected milk production,the results showed that the two time points and the highest daily milk production were significantly correlated with the 20-week corrected milk production（P<0.01）.,the correlation coefficients were 0.967,0.938,and 0.885,respectively;the correlation analysis of Xinjiang donkeys at different time points,the highest daily milk production and the 20-week corrected milk production showed that 8:00,20:00,and the highest daily milk production were corrected for 20 weeks.The milk production was extremely significantly correlated;the regression equation of 8:00,20:00 and the highest daily milk production jointly predicted the 20-week milk production of Xinjiang donkeys was Y=196.53+73.42 X₁+46.35X₂-0.97 X₃,and the regression equation had a significant correlation.