Recessive. Dairy Mastitis Occurrence Rules

In this study,the variability of somatic cell counts in the milk and milk component of Chinese Holstein cattle were studied,and study on subclinical mastitis in Milk Cow in Area in Fujiang,the diagnositic mechanisms of cow subclinical mastitis were studied by analyzing the relationship between somatic cell count(SCC) and NAGase activity and between the pH value and the concentrations of Cl~- in milk and blood.1.Study on variability of somatic cell counts in the milk and milk component of Chinese Holstein cattleIn order to study the variability between somatic cell counts in the milk and milk component of Chinese Holstein Cattle.Data included 39955 DHI test month records of Somatic Cell Counts(SCC) in milk for 2784 cows from 5 herds of changfu dairy group since 2006 to 2007 were analyzed by the method of least squares.Results showed that means and standard deviation of SCC were 460.55×1000/ml±504.76×1000/ml,respectively.Different herds,month,milking month and parity affected SCC significantly(P＜0.01),but calving seasons did not affect SCC significantly(P＞0.05).SCC increased when parities or milking months increased.Along with the variety of somatic cell in the milk,the composition of raw material milk obvious change.The content of dry matter,fat,protein was significantly positively related with SCC(P＜0.01).The content of lactose was significantly negatively related with SCC(P＜0.01).2.Study on Subclinical Mastitis in Milk Cow in Nanping Area in Fujiang980 lactating milk COWS and 3872 mammary regions had been detected by SMT method to determine the incidence of subclinical mastitis in three dairy farms area in Fujiang province.The results indicated that the positive rate of subclinical mastitis with different months and different farms.The positive rate of mammary in July was significant different than that of in March and May.The left mammary regions had no significantly different positive rate of subclinical mastitis than the right(P＞0.05),the incidence of subclinical mastitis were 41.58%and 42.70%respectively.The retral mammary regions had significantly higher positive rate of subclinical mastitis than the anterior(P＜0.05),the incidence of subclinical mastitis were 40.05%and 44.23%,respectively.According to the statistics,we obtained the result that the incidence of subclinical mastitis had significant relationship(P＜0.05)with the age.The positive amount of subclinical mastitis had significantly effect on the fetal sequences and milking month(P＜0.05).There were significant different in the incidence of subclinical mastitis among three different milking stages.3.Effect of subclinical mastitis on milk and blood parametersCMT was used to detect the incidence of mastitis and 90 bovines were allotted as three groups:control group(healthy group),experimental groupⅠ(subclinical mastitis) and experimental groupⅡ(clinical mastitis) according to the result of mastitis.Each has 30 bovines.NAGase activity was measured to analyze the difference.The cholridion concentration and the pH in the milk and blood were tested.The result showed that there was significantly different in NAGase activity among different groups(P＜0.01).the chloridion concentration and pH in blood and milk of subclinical mastits cows were significantly higher than those in healthy cows(P＜0.05).The higher chloridion concentration was,the more serious mastitis the cows had.The chioridion concentration in milk of healthy cows was significantly higher than that in milk of subclinical cows and there was significantly difference among the milks of healthy cows,subclinical mastits cows and suspect cows in chioridion concentration(P＜0.01).The higher the pH of milk was,the more serious mastitis the cows had.The pH in milk of healthy cows was significantly higher than that in milk of suspect cows and there was significantly difference among the milks of healthy cows, subclinical mastits cows and suspect cows in pH(P＜0.05).