Voluntary intake, milk production and plasma metabolites in nursing mares fed two different diets.

The research investigates the effects of two different diets, primarily composed of hay and concentrates, on the food intake, milk production and plasma metabolites in nursing mares in their first two months of lactation. The study found notable differences in these parameters between the two diet patterns, suggesting diet composition influences these factors significantly.

Study Purpose and Design

• The research aimed at studying the difference in voluntary food intake, milk yield and composition, and blood metabolites during the first two months of lactation in nursing mares.
• The experiment involved two different diets – one with 95% hay and 5% concentrates (Diet F) and the other with 50% hay and 50% concentrates (Diet C).

Key Findings

• Mares on Diet C had a higher voluntary food intake than those on Diet F, with the actual figures at 22.9 kg and 21.4 kg of dry matter in the 4th week respectively.
• It was observed that both diets were eaten in amounts that exceeded the energy requirements, but this was especially true for Diet C.
• Mares fed Diet C also produced more milk daily by the 4th week, as compared to those on Diet F – 26.4 kg and 23.4 kg, respectively.

Dietary Impact on Milk Composition

• Milk from mares on Diet F had higher concentrations of fat and protein than those on Diet C. However, these levels decreased from the stage of colostrum (first milk produced after giving birth) to the 8th week.
• Lactose concentration was higher in the milk from mares fed Diet C than from those on Diet F and increased from colostrum to the 8th week.
• The amounts of different minerals in the milk mainly varied according to the stage of lactation.
• Milk fat was higher in linolenic acid and lower in linoleic acid for mares fed Diet F than for those fed Diet C.

Plasma Metabolites Analysis

• Glucose concentration was higher in the plasma of mares fed Diet C.
• The plasma of mares fed Diet F had higher concentrations of 3-hydroxybutyrate and acetate.