engleski

CONCENTRATION OF RETINOL AND Β-CAROTENE IN PLASMA OF SUCKLING CALVES

Retinol (vitamin A) and β-carotene are protecting epithelia from bacterial and viral infections which are primary causes for sickness and death of calves. The concentration of retinol and β-carotene in blood of calves is determined with their content in colostrum and milk in crucial first days of life and then with their content in milk/milk replacer and starter feed mix. The aim of this study was to determine variations of retinol and β-carotene concentrations in plasma of calves up to 42 days of age. The animal trial was conducted on 12 calves at high milk production dairy farm Kapelna fed the same isoprotein and isoenergetic diets. Blood samples were taken on the first (after calves drank colostrum), third, 21st and 42nd day of calves age, and at the same days, samples of diets (colostrum, milk, milk replacers, and starter feed mix) fed to calves were also taken. β-carotene and retinol were extracted with hexane from all samples and quantified using reverse phase HPLC method. Concentrations of β-carotene and retinol in colostrum were on average 73 and 137.3 μg/dL, in milk 9.5 and 27.9 μg/dL, milk replacer 5.2 and 6 μg/dL, while their content in starter mix was 16.4 and 57 μg/g DM, respectively. Concentrations of β-carotene and retinol in plasma of new-born calves were 14.3 and 9 μg/dL, on the third day of age 4.9 and 7.3 μg/dL, on 21st day 7.4 and 8.4 μg/dL a nd 42nd day 3.9 and 9.8 μg/dL, respectively. β-carotene and retinol concentrations in the diet affected their respective concentrations in blood plasma of calves. Colostrum had the highest concentration of retinol, and thus the highest concentration was in new-born calves. Calves with the lowest retinol concentration in plasma died before the end of the trial. Concentration of retinol and β-carotene is important for the survival rate of calves.

retinol, β-carotene, suckling calves, pasma

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