Evaluation of milk urea concentrations and their relationship with milk production, rumen degradable proteins imbalance and cow's fertility in a dairy farm in Haouz, central Morocco

The effect of some factors on relationships between milk urea concentrations, milk production, negative OEB diet and fertility of 74 cows were analyzed. Diets were calculated using the French PDI system and SPSS 20 package was used for statistical analysis. Milk urea concentrations ranged from 31.7± 1.6 mg/dl in low-producing cows (17.3 ± 2.3 kg milk) to 32.3 ±2.0 mg/dl in high-producing cows (25.1 ± 4.4 kg milk). The increase of milk urea concentrations was found to increase interval between calving and conception (p< 0.00), number of inseminations per conception (p <0.01) and interval between two successive calvings (p<0.00). Increasing of urea in milk in relation with feeding diets characterized by negative OEB might decrease milk production and fertility in dairy herd. Therefore, dairy breeders may find it advantageous to monitor milk urea, which could help to improve nutritional status and cow's fertility.