Abstract: In this study, effects of horse pregnancy time，age and urine volume on concentrations of conjugated estrogen of Yili horse were analyzed, and the results would provide the basis for animal conjugated estrogen production. Total 35 pregnant Yili horses with same rearing conditions were divided by horse age into 3 groups. Within the 28 to 38 weeks of horse pregnancy, urine samples from Yili horse were collected dividedly and urine volumes of 24 h were recorded weekly. Concentrations of conjugated estrogens in the samples were determined by HPLC. Effects of the pregnancy time and horse age on concentrations of conjugated estrogens were statistic analyzed by least squares analysis process with SAS 8.1. Correlation between urine volume and concentrations of conjugated estrogens was determined by correlation analysis process.The results showed that concentration of conjugated estrogens was affected extremely significantly by pregnancy time （P＜0.01）; concentrations of sodium estrone sulfate and sodium equilin sulfate were affected extremely significantly by horse age （P＜0.01）, but concentration of sodium 17α-dihydroequilin sulfate was not affected by horse age （P＞0.05）. The correlation analysis showed that there were extremely significant negative correlations between urine volume and 17α-dihydroequilin sulfate, sodium equilin sulfate （P＜0.01）. There was no significantly negative correlation between urine volume and sodium estrone sulfate （P＜0.05）. Thus the pregnancy time was the key factor to affect concentration of conjugated estrogens. Concentrations of conjugated estrogens could be improved by collecting urine from the pregnant horse under 13 ages and extremely significantly negative correlation with urine volume.

Key words:

Yili horse; conjugated estrogens; pregnancy time; age; urine volume