engleski

The effect of milk protein polymorphism and breeds on somatic cell count in bovine milk

Somatic cell count in bovine milk is an indicator of udder health with a direct influence on the production profitability by milk price, influence on animal fitness, and the usability of milk for processing. The aim of this paper is to identify the effect of milk protein polymorphism on somatic cell count in bovine milk. A research was carried out on 160 Holstein, Simmental and Brown Swiss cows. In the first three lactations the average somatic cell count in bovine milk was determined monthly for each animal. Genetic variants of beta- lactoglobulin (β-LG) and capa-casein (κ-CN) were determined using PCR-RFLP method. Although the lowest somatic cell count was found in the cows milk with BB β-LG (159 300 /mL), when compared with the somatic cell count of the cows with AA and AB genotypes, the differences were not significant. A somatic cell count in milk was not found to be influenced by κ-CN genotype. The influence of breed on somatic cell count in milk was significant (p<0.001). Milk from Simmental cows have had the lowest average somatic cell count (117 500 /mL), whereas milk from Holsteins and Brown Swiss cows had a significantly higher somatic cell count (181 800/mL and 224 200 /mL, respectively). The number of lactation (L1-L3) had a significant influence on somatic cell count in milk (p<0.001). The lowest somatic cell count was found in the milk of first lactation cows (125 100 /mL), whereas the somatic cell count in the third lactation was significantly higher (252 000 /mL). The results of the research confirmed the proposition about significant effects of breed on somatic cell count in milk, while the relationship between milk protein polymorphism and somatic cell count in milk was not significant.

cow milk; somatic cell count; breed; protein polymorphism

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