Vitamin A profiles of equine serum and milk.

This research study examines how Vitamin A levels change in equine mares and their foals after birth, noting that the peak of Vitamin A in mare milk occurs one day after birth, 3 days before the maximum level of Vitamin A in the foal’s serum.

Overview of the Study

• The investigators conducted this research to understand the chronology and variations of Vitamin A in the blood and milk of mares as well as in the blood of their foals following birth. The samples of serum (a component of blood) and milk were taken at the point of parturition (childbirth) and regularly afterwards, up until 21 days postpartum, with observations made at regular intervals.

Key Findings

• The research observed that the highest level of Vitamin A activity in the mare’s milk occurred just one day after parturition. This level was recorded three days before the maximum Vitamin A activity in the foal’s serum, which coincided with the lowest concentration of Vitamin A in the mare’s serum.
• The article reported that the mare’s serum contained a ratio of around 65:35 retinol to retinyl palmitate. Retinyl palmitate and retinol are different forms of Vitamin A. Retinyl acetate, another form of Vitamin A, made up less than 1% of the mare’s serum.
• Initially, retinyl palmitate was the dominant form of vitamin A in the mare’s milk. However, a transition occurred between the second and third day postpartum, where retinyl acetate became and remained the dominant form. Retinol comprised less than 1% of the milk’s Vitamin A content.
• In the foal’s serum, a significant amount of retinyl acetate was recorded four days after birth. However, after this point, the levels of retinyl acetate in the foal’s serum seemed to remain unaltered by the increasing levels of retinyl acetate in the mother’s milk.

Significance of the Study

• This study has important implications for our understanding of nutrient transfer in breast milk. It’s suggestive that changes occur in the forms and concentration of Vitamin A as milk is ingested by the foal. These changes might be crucial for the health and development of the infant horse.
• Further research can be built on these observations, possibly exploring the behavioural and physiological effects of these changes in Vitamin A levels and forms. This may offer insights for both equine health and potentially other mammalian species.