Published in Scientific Papers. Series D. Animal Science, Vol. LXVII, Issue 2
Written by Mugurel COLĂ, Florica COLĂ
This study aimed to achieve the optimal energy balance of Holstein-Friesian cows, fed to produce 5,000-6,000 l of milk/cow per lactation (restricted production- Pr) on a pasture ration or 8,000-9,000 l of milk/cow per lactation (high production- Pm), on a more intensive feeding regimen using a partial mixed ration (pasture + concentrate). The mean of 4% fat-corrected milk (FCM) and standard deviation was 8,646 ± 1,162 l/cow per lactation for the Pm herd and 6,847 ± 787 l/cow per lactation for the Pr herd. In the first period of lactation, the balance degree estimated negative energy was lower in Pm cows than in Pr cows (-16.1 vs. -29.1 MJ/cow per day, respectively). As such, mobilization of body reserves was also lower in Pm cows, and this was reflected in lower concentrations of nonesterified fatty acids (0.7 vs. 0.8 mmol/l) and β-hydroxybutyrate (0.5 vs .0.7 mmol/l) and higher concentrations of glucose (3.5 vs. 3.3 mmol/l) and insulin for Pm and cows respectively, Pr.
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