Protein and nitrogen composition of equine (Equus caballus) milk during early lactation.

The research explores the changes in protein and nitrogen composition in a horse’s milk over the early lactation period.

Objective and Methodology

• This study aimed to explore how the concentration of proteins, such as the true protein, whey protein, and casein, and the composition of nitrogen change during the early stages of lactation in horses.
• To achieve this, researchers separated whey protein from casein in equine milk using ultracentrifugation and pH adjustment, but without adding calcium.

Findings

• The research found significant decreases in the concentrations of true protein, whey protein, and casein during the initial 28-day phase of lactation.
• The most notable change was found in the level of whey protein.
• In addition, the ratio of nitrogen in whey protein to casein declined from 85:15 to 54:46 over the 28-day period.
• Meanwhile, non-protein nitrogen levels hovered consistently at 500 mg nitrogen/liter, but in proportional terms, they increased from making up 2% to 13% of the total nitrogen content over the first 28 days of lactation.

Conclusion and Implications

• The study validates the unique nitrogen composition in equine milk, indicating that it falls between that of human and ruminant milk in terms of its composition.
• This unique composition changes over the course of early lactation and these findings may have implications for feeding and nutritional planning in the care of foals and other young horses.