The effect of season on the content of urea in milk of cows
1995
Rajcevic, M. (Mercator, Ljubljana (Slovenia)) | Jazbec, I. (Ljubljana Univ. (Slovenia). Veterinary Fac.) | Sirk, M. (M-Kmetijsko gozdarska zadruga Litija, Litija (Slovenia))
Cows of Friesian breed from the farms A and B were taken into research in the years 1992 - 1994 to determine the urea (and protein) in milk and to establish the deficient or sufficient supply with protein. Winter and summer periods were studied separately. On the both farms the content of urea in milk increased in summer, on the farm A it was on average (n=60) 5.24 +/- 0.57 mmol/l and on the farm B (n=68) 7.82 +/- 0.804 mmol/l. In the winter the urea in milk was on average (n=60) 3.57 +/- 0.534 mmol/l on the farm A and 5.01 +/- 0.745 mmol/l (n=100) on the farm B. On the both farms the difference in the average concentration of urea between the winter and summer was statistically highly significant (p=0.001) and is due to nutrition regime or to unbalance of rations with energy and protein.
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