Seasonal and diurnal rhythms determine the life cycle of many animal species. In equids this is not only true for wild species such as the Przewalski but season-dependent metabolic changes also exist in domesticated horses. Horses can reduce their metabolic activity during the cold season and thus reduce heat loss. The effects of such seasonal changes on pregnancy and foetal development, however, have not been investigated so far. Researchers from Vetmeduni Vienna could now demonstrate that foals born in winter are smaller than herd mates born later in the year.
Seasonal and diurnal rhythms determine the life cycle of many animal species. In equids this is not only true for wild species such as the Przewalski but season-dependent metabolic changes also exist in domesticated horses. Horses can reduce their metabolic activity during the cold season and thus reduce heat loss. The effects of such seasonal changes on pregnancy and foetal development, however, have not been investigated so far. Researchers from Vetmeduni Vienna could now demonstrate that foals born in winter are smaller than herd mates born later in the year.
Reduced metabolims hits a critical foetal phase
The last weeks of pregnancy correspond to a time of rapid foetal growth. This phase is a key moment for development of the foal. „When a foal is born in winter, it is thus likely that the seasonal reduction in energy metabolism affects the foetus“, explains principal investigator Christine Aurich.
To test their hypothesis, the scientists studied 27 broodmares and their foals at the Graf Lehndorff Institute, a joint research unit of Vetmeduni Vienna and the Brandenburg State Stud at Neustadt (Dosse), Germany. Mares and foals were allocated to three groups by the date of foaling. Foalings occurred between February and early March in Group 1, from early March until early April in Group 2 and from mid-April to May in Group 3. From all foals, weight and a variety of parameters to assess their size were determined repeatedly from birth to an age of 12 weeks. In addition, weight and size of the placenta were determined at foaling.
Read more at University of Veterinary Medicine -- Vienna
Image: Foals born in summer are bigger than those born in winter. (Credit: Juliane Kuhl/Vetmeduni Vienna)
