[Variations in plasma components in lactating mares at late pregnancy-early lactation (author’s transl)].

The research article explores the changes in plasma components in pregnant and lactating mares compared to non-pregnant mares and how these changes might indicate the metabolic usage of energy, nitrogen, and minerals. The findings suggest that beta-hydroxybutyrate, magnesium and glucose are mainly affected and that the increase in food intake from late pregnancy to early lactation could be due to increased nutrient requirements.

Research Methodology

• The researchers conducted an experiment involving pregnant then lactating mares and dry non-pregnant mares to study the changes in plasma components.
• The plasma components studied were used as indicators of the utilization of energy (glucose, non-esterified fatty acids, beta-hydroxybutyrate), nitrogen (urea, proteins) or minerals (calcium, phosphorus, magnesium).
• The mares were given 2 kg of concentrate and hay daily without any restrictions on consumption.

Key Findings

• Beta-hydroxybutyrate, magnesium and to a lesser extent glucose were the only constituents that showed changes in their levels during the period starting one month before and ending one month after the foaling process.
• The levels of non-esterified fatty acids and urea, which are known indicators of body lipids mobilization and nitrogen status respectively, remained constant throughout the study period. This suggests that these components were not greatly affected by the transition from pregnancy to lactation.

Interpretation and Conclusion

• The researchers interpret the constant levels of non-esterified fatty acids and urea as possibly indicating that there was no significant mobilisation of body lipids or change in nitrogen status with the transition from pregnancy to lactation.
• The increase in food consumption observed from late pregnancy to early lactation is suggested to be due to an increase in nutrient requirements, rather than a metabolic change.
• This study thus provides insights into the metabolic fluctuations in mares during the transition from pregnancy to lactation, particularly in relation to the usage of energy, nitrogen and minerals.