Zinc, copper and selenium deficiencies in broodmares in south-eastern Poland.

Zinc, copper, and selenium deficiencies were examined in pregnant mares from south-eastern Poland to assess their levels during pregnancy, revealing widespread zinc deficiency and localized copper and selenium deficiencies, despite no evident clinical symptoms.

Study Objective and Importance

• The research focuses on microelement deficiencies—specifically zinc, copper, and selenium—in broodmares (pregnant female horses) and their implications for fertility and fetal development.
• Trace element deficiencies in horses can lead to reproductive issues and developmental disorders in foals.
• The goal was to measure and control the concentrations of these elements in the blood serum of pregnant mares in various regions.

Study Design and Population

• Total of 154 pregnant mares were included, all in the second half of pregnancy.
• Mareshoused in five distinct geographical regions within south-eastern Poland: Łęczyńsko-Włodawska Plain, Chełmskie Hills, Łukowska Plain, Beskid Niski, and Działy Grabowieckie.
• Studying multiple regions helps to identify regional differences in microelement status.

Methodology for Trace Element Measurement

• Blood serum samples were collected from the mares.
• Concentrations of zinc, copper, and selenium in serum were measured using atomic absorption spectrophotometry, a precise technique commonly employed to detect metal concentrations.
• Reference ranges for these trace elements were applied to assess deficiency status.

Key Findings

• Zinc levels across all mares were below the reference range of 14.9-29.2 μmol/l, with the highest measured concentration being 10.7 μmol/l, indicating universal zinc deficiency in the sample population.
• The lowest copper and selenium levels were specifically found in mares from the Beskid Niski region, indicating regional variation and localized multiple deficiencies.
• All regions showed zinc deficiency; only Beskid Niski had both copper and selenium deficiencies alongside zinc deficiency.

Clinical Outcomes and Interpretation

• Despite the detected trace element deficiencies, all mares delivered newborn foals on time, and no clinical deficiency symptoms were observed in the mares or foals.
• This suggests that the deficiencies were likely subclinical—meaning the animals were not showing overt health problems, but biochemical deficits were present.
• Subclinical deficiencies can still impact long-term health or performance, although immediate reproductive success was unaffected.

Implications and Recommendations

• The presence of widespread zinc deficiency and localized copper and selenium deficiency indicates a potential need for dietary supplementation or management changes in these horse populations.
• Regular monitoring of trace elements in pregnant mares is important to prevent possible reproductive problems or developmental issues in foals.
• Further research might be needed to assess the impact of these subclinical deficiencies on mare and foal health over longer periods or under different management conditions.