RELATIONSHIP BETWEEN SERUM TOTAL CHOLESTEROL LEVELS BEFORE CALVING AND OCCURRENCE RATE OF DISEASES AFTER CALVING IN HOLSTEIN HEIFERS AND COWS

The relationship between serum total cholesterol levels 20 days before calving and disease occurrence rate in relation to milk producing capacity after calving was investigated. In cases where peak daily milk yield were below 30kg, the disease occurrence rate in cows with total cholesterol levels between 120-170mg/dl and those with levels below 120mg/dl were 22.6% and 63.9%, respectively. The disease occurrence rate in cows with total cholesterol levels less than 120mg/dl was significantly higher (P<0.01). Similar observation was made in cows with peak daily milk yield of over 30kg. In this group moreover, cows with total cholesterol levels of more than 170mg/dl have significantly lower disease occurrence rate as compared to those with total cholesterol levels less than 120mg/dl (P<0.01). From these results, the prophylactic diagnosis using total cholesterol level and peak milk yield was found useful as an indicator to predict the occurrence of diseases after calving on farms with average milking yield between 5,000kg to 6,500kg/year