Effect of selenium supplementation and plane of nutrition on mares and their foals: foaling data.

This research study evaluates the effects of selenium supplementation and different nutritional planes on pregnant mares and their offspring. The study observed that maternal diet, specifically, the inclusion of supplemental selenium and grain mix, during the late stages of pregnancy can influence placental efficiency and the quality of the first milk (colostrum) the mares produce after giving birth, particularly its IgG content.

Objective of the Research

• The primary focus of this study was to investigate how altering maternal plane of nutrition and adding selenium yeasts to the diet, might impact foaling variables and the passive transfer of immunoglobulin G (IgG) from the mare to the foal through colostrum. This IgG is crucial for the newborn foal’s initial immune response.

Methodology of the Research

• The study used a randomized complete block design involving 28 Quarter Horse mares, which were segregated according to their expected foaling date.
• They created four dietary plans by varying the proportions of a pasture diet, a grain mix, and selenium yeast (0 or 0.3 mg/kg).
• The four resulting treatments were Pasture (PA), Pasture + Selenium (PS), Pasture + Grain Mix (PG), and Pasture + Grain Mix + Selenium (PGS).
• Selenium supplementation was initiated 110 days before the expected foaling date. The dietary treatments continued until parturition.
• Data to be collected included foaling variables (like birth weight and time of birth), placental weight, placental cell characteristics, and IgG concentration in colostrum and foal serum.

Findings of the Research

• The addition of Selenium or variations in the plane of nutrition did not significantly affect the studied foaling variables.
• However, the foals from the groups where mares were fed a grain mix tended to have a lower birth weight relative to the mare’s weight.
• The supplementation of Selenium did not appear to impact placental cell number, activity, expulsion time, or weight, although it did seem to decrease placental cell size.
• The colostral IgG concentration seemed lower in the groups where mares were fed a grain mix, suggesting that the additions to the diet might impact the immune support the foals receive through colostrum.
• The overall level of IgG in the foals’ serum also appeared to be lower in the groups where mares were fed grains.

Conclusion of the Research

• The findings suggest that the diet of a mare during the last third of gestation, particularly the incorporation of a grain mix and selenium, influences the placental function and the quality of colostrum, specifically regarding the IgG content. This could potentially have implications for foal health, as IgG is an essential component of the foal’s early immunity.