Differences in serum iron concentrations between the summer and winter in Noma horses.

The research investigated how iron levels in the blood of Noma horses vary between summer and winter. It found that iron concentrations, along with other related blood parameters, tend to be lower in summer than in winter and suggested that factors such as sweating, skin conditions, insect bites, and diet might contribute to this fluctuation.

Sampling and Test Results

• The researchers took a series of blood samples from 37 healthy Noma horses over a substantial period of time, with samples taken in September 2018, February 2019, October 2019, February 2020, September 2020, February 2021, and February 2022.
• The results of these tests showed that serum iron levels in the horses’ blood fluctuated between 74 μg/dl to 316 μg/dl, with an average value of 176 μg/dl.
• There were differences noted based on the horses’ sex and age, with stallions having lower iron concentrations than mares and geldings, and horses aged 10-14 years having lower iron levels which then rose as the horse aged.

Seasonal Variations

• There were clear patterns identified in the iron levels based on the season, with levels repeatedly found to be low during the summer months but high during the winter months.
• Alongside iron, several other factors, such as total iron-binding capacity, hemoglobin, hematocrit, albumin, cholesterol, sodium, potassium, chloride, and calcium were also lower in the horses during summer.
• Conversely, levels of creatinine, total protein, inorganic phosphorus, and magnesium were found to be higher during the summer months.

Potential Causes for Seasonal Variations

• The researchers suggest several potential explanations for the observed decrease in iron levels during the summer months.
• Factors like increased sweating due to the higher temperatures, skin conditions such as dermatitis, bites from insects, and variations in diet could all potentially contribute to a loss of iron from the horse’s system, leading to the lower levels observed.

Correlations

• Notably, the study found that the horses’ serum iron concentrations correlated with several other factors.
• Positive correlations were observed with hemoglobin, total iron-binding capacity, the iron saturation rate, hematocrit, and several other factors.
• Meanwhile, negative correlations were seen with blood urea nitrogen and potassium levels.