Concurrent lactation and pregnancy: pregnant domestic horse mares do not increase mother-offspring conflict during intensive lactation.
Authors: Bartošová Jitka, Komárková Martina, Dubcová Jana, Bartoš Luděk, Pluháček Jan
Journal: PloS one
Summary
# Editorial Summary The physiological demands of lactation represent one of the most metabolically costly phases of equine reproduction, yet many mares conceive again within weeks of foaling, creating a potential conflict between supporting a nursing foal and investing in a developing foetus. Bartošová and colleagues examined whether this concurrent lactation-pregnancy scenario intensifies mother-offspring conflict during early gestation by analysing suckling behaviour patterns—including bout duration, frequency, and rejection rates—in pregnant versus non-pregnant lactating mares over the first two trimesters of pregnancy. Rather than exhibiting increased conflict as predicted, pregnant mares actually demonstrated *enhanced* nursing engagement, offering longer suckling bouts without increasing rejection or termination of nursing compared to non-pregnant counterparts. This counterintuitive finding suggests mares employ a strategic compensation mechanism in early pregnancy: by promoting more generous lactation before foetal energy demands escalate, they appear to prepare their foals for the inevitable earlier weaning that pregnancy-related maternal conflict will trigger during later gestation. For equine professionals managing breeding mares, these findings indicate that early-pregnancy lactation disruption is not an immediate concern; instead, the critical management window for addressing potential nutritional stress and foal behavioural adjustment occurs during the final trimester when weaning conflicts genuinely intensify.
Read the full abstract on PubMed
Practical Takeaways
- •Foals nursing pregnant mares do not experience increased rejection or weaning pressure during the first two trimesters of pregnancy, contrary to earlier assumptions
- •Pregnant mares actively increase suckling bout duration early in pregnancy, potentially optimizing foal nutrition before later weaning
- •Expect normal nursing behaviour and foal development in mares that become pregnant shortly after foaling, with weaning timing being the primary management consideration
Key Findings
- •Pregnant mares did not increase rejection or termination of suckling compared to non-pregnant mares during early pregnancy
- •Pregnant mares provided longer suckling bouts than non-pregnant mares, suggesting enhanced nursing behaviour in early pregnancy stages
- •Mother-offspring conflict decreased rather than intensified during first two trimesters of pregnancy in lactating mares
- •Pregnant mares appear to compensate nursing foals with enhanced access before anticipated early weaning