Blood selenium in naturally fed horses and the effect of selenium administration.

The research paper investigates the levels of the trace element selenium (Se) in the blood of naturally fed horses, and how these levels change when the horses are fed with an increased volume of selenium.

Key Findings

• The average blood selenium level in adult horses, in the study, was observed to be between 25.8 and 27.0 ng/ml across different farms. This was in correlation with the average selenium content in the food they consumed which was approximately 20 ng/g dry substance.
• However, in experimentally fed horses who were given high selenium diet (41 ng Se/g food), the blood selenium level was found to be significantly higher, at 45.3 ng/ml. This illustrates that the selenium levels in horse blood are directly proportional to their selenium intake.
• The study noted that foals, which were nursing, had higher selenium levels compared to adult horses when their selenium intake was low. But, with high selenium intake, adult horses exhibited higher selenium levels.
• The selenium levels of horse milk was found to slowly increase with the rise of selenium in the mare’s blood. This suggests that the intake of selenium affects not only the blood selenium levels but also the selenium concentration in mare’s milk.
• No difference was observed between the selenium levels in blood plasma and blood cells, indicating that selenium is uniformly distributed within the horse’s blood.
• The research also experimented with varying dose levels of selenium. It was found that a weekly selenium intake between 1.5 to 6 mg caused a linear increase in blood selenium levels. Larger doses (such as 18 and 30 mg per week) did not significantly elevate the blood selenium levels beyond the elevation caused by a 6mg weekly dose.

Significance of Research

• Overall, the study contributes to a better understanding of selenium dynamics in horses’ blood, milk, and it’s relation to their diet. This knowledge might help in designing nutrition plans or interventions aimed at optimizing selenium levels in horses based on their age and reproductive status.
• The finding that high doses of selenium do not correspondingly increase blood selenium levels beyond a certain threshold could prevent unnecessary supplementation and potential toxic effects, thus contributing to the overall health and well-being of the horses.
• The observation regarding selenium transfer from mare’s blood to milk, provides insights into the dynamics of selenium transfer from mother to offspring, allowing for better nutritional planning for nursing foals.