Abstract:
This study investigates the relationship between milk biochemical composition and management parameters in dairy
cows, focusing on fat, protein, casein, lactose, urea, beta-hydroxybutyrate (BHB) concentrations, days in lactation (DIM),
lactation, age and fat-to-protein (G/P) ratio. Milk samples from 55 cows were analyzed to evaluate the impact of
nutritional and metabolic imbalances on milk quality. The fat-to-protein (G/P) ratio and milk urea content served as key
indicators of energy balance and protein metabolism. A strong positive correlation was found between fat and protein
concentrations (r = 0.76, p < 0.001), while lactose showed a significant negative correlation with both fat (r = -0.54, p <
0.001) and protein (r = -0.45, p < 0.001). The analysis shows that cows with low G/P ratios (indicative of an energy
surplus) cluster around 100 and 250-300 days in lactation, but these differences are not statistically significant (p = 0.4627,
p = 0.1936). In contrast, cows in the Protein Excess group (urea > 25 mg/dl) cluster around 100 and 200-300 days, with
statistical significance (p = 0.0046). This suggests that protein excess varies across lactation stages, highlighting the need
for dietary adjustments to optimize protein metabolism during these periods.
