Use of urea by early postpartum Holstein cows

Area of Science:

• Animal Science
• Dairy Nutrition
• Ruminant Physiology

Background:

• Urea supplementation is explored as a nitrogen source for dairy cows.
• Optimizing nitrogen utilization is crucial for milk production efficiency.

Purpose of the Study:

• To evaluate the efficacy of urea nitrogen in high-energy complete rations for lactating Holstein cows.
• To assess the impact of urea supplementation on milk yield, nutrient digestibility, and nitrogen utilization.

Main Methods:

• Thirty-nine lactating Holstein cows were assigned to four dietary treatments differing in crude protein and urea content over 12 weeks.
• Milk production, energy digestibility, and nitrogen balance were measured.
• Rumen fluid and plasma urea nitrogen concentrations were analyzed.

Main Results:

• Milk production increased significantly in cows fed urea-supplemented diets compared to the negative control.
• Energy digestibility was higher in diets containing urea.
• Plasma urea nitrogen concentrations indicated effective utilization of supplemental urea.

Conclusions:

• Lactating cows in early lactation can effectively utilize urea nitrogen when fed high-energy complete rations.
• Low nitrogen solubility of feed ingredients is important for efficient urea utilization.
• Urea supplementation can be a viable strategy to enhance milk production in dairy cows.