THE EFFECT OF BLOOD AND MILK SERUM ZINC CONCENTRATION ON MILK SOMATIC CELL COUNT IN DAIRY COWS

The objective of this study was to evaluate the influence of blood and milk zinc concentration on somatic cell count, milk production and occurrence of subclinical mastitis cases. The study was performed on thirty Holstein cows approximate same body weight, ages 3 to 5 years, with equally milk production. Blood samples were taken after the morning milking from the caudal vein and milk from all four quarters was taken during morning milking. All samples of blood and milk were taken to determined zinc, using inductively coupled plasma mass spectrometry. 37.67% (11/30) cows have blood serum zinc concentration below 7µmol/l, and 63.33% or 19/30 cows have blood serum zinc concentration higher then 13µmol/l. Also 30% (9/30) cows have somatic cell count lower then 400.000/ml which indicate absence of subclinical mastitis, but 70% (21/30) cows have somatic cell count higher then 400.000/ml which indicate subclinical mastitis. According to all results in this research, zinc has very important influence on reducing subclinical mastitis and somatic cell count in milk of dairy cows.