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Study On The Dose-Effect Relationship Between The Number Of Bovine Milk Cells And The Quality Of Raw Milk And Its Prevention And Control Technology

Posted on:2020-10-22Degree:MasterType:Thesis
Country:ChinaCandidate:H P ZhangFull Text:PDF
GTID:2393330599450505Subject:Agricultural Extension
Abstract/Summary:PDF Full Text Request
The somatic cell count(SCC)of cow milk can accurately reflect the quality of cow milk and the health status of individual cows.It has been widely used as a reliable index to predict mastitis.SCC management is an effective way to improve the quality and quantity of feed milk.In this paper,the dose-effect relationship between milk SCC and raw milk yield and quality,as well as the factors causing SCC changes in raw milk and the prevention and control measures were explored.The results showed that:(1)There was a significant negative correlation between SCC and milk yield(p<0.05),and milk yield decreased with the increase of SCC;milk yield was the highest when SCC was less than 2.0×10~5/mL,which was significantly different from that when SCC was more than 5.0×10~5/mL.When SCC was less than 2.0×10~5/mL,the milk fat rate,milk protein rate and lactose rate were the highest,which were significantly higher than those when SCC was more than 5.0×10~5/mL(p<0.05).There was a significant negative correlation between SCC and total solids(p<0.05),but there was no significant correlation between SCC and non-fat milk solids.(2)SCC was positively correlated with NGA and peroxidase(p<0.01),and positively correlated with PL,lipase and catalase(p<0.05).With the increase of SCC in raw milk,the activities of PL,NGA,catalase and peroxidase increased significantly(p<0.05).The activities of PL,NGA,catalase and peroxidase in raw milk with SCC≥10.0×10~5/mL were significantly higher than those in SCC≤10.0×10~5/mL(p<0.05).The activities of lipase increased with the increase of SCC in raw milk,but there was no significant difference.(3)There was a significant positive correlation between SCC and parity(p<0.05).With the increase of parity,SCC showed an upward trend;heat stress caused by summer made SCC significantly higher than that in other seasons(p<0.05);the larger the dairy farm under the same conditions,the lower SCC;mastitis increased SCC in raw milk;compared with artificial milking,SCC in raw milk of machine milking was relatively low and of higher quality.The increase of SCC will reduce the quality of raw milk in varying degrees,improve the level of feeding management,control the life of dairy cows,and take measures to reduce the impact of environmental factors on SCC.It is an effective measure to reduce SCC and improve the quality of raw milk.
Keywords/Search Tags:somatic cell counts, raw milk, quality, measure
PDF Full Text Request
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