Latest Research into Foal Size at Birth

Our weather seasons have long been known to determine behaviour, metabolism and reproductive activity in many animal species, including horses. Fascinating new research from researchers at the University of Veterinary Medicine in Vienna has proved a theory of many horse breeders that winter foals are smaller than the spring foals, which are traditionally considered ideal. The research found that foals born in winter were shorter at the withers, with shorter legs than foals born in the warmer months.

Scientists believe a seasonal reduction in energy metabolism in the mare affects foetus size at a crucial stage, as even in domesticated horses, metabolic activity is reduced in winter.

Christine Aurich, the principle researcher said “Horses can reduce their metabolic activity during the cold season to reduce heat loss. The last weeks of pregnancy correspond to a time of rapid foetal growth. This phase is a key moment for development of the foal.”

In the study all foals were assessed on weight and a variety of parameters to assess their size including the size of the placenta. Their measurements were taken from birth to 12 weeks to determine a conclusion of the research.

So with this new research in mind how can we are horse owners support our broodmares alongside aiming for foaling in warmer temperatures?

A broodmare’s feeding programme should be divided into three stages as whilst mares should be fed a quality maintenance diet for the first half of their pregnancy, a maintenance feeding program just 'won’t cut it' after the mid-way point of the pregnancy. It is important to bear in mind that the last trimester of a mare’s pregnancy is when 60% of foetal growth occurs and the mare's energy requirements will increase by around 20%. Mares should be at about a body condition score of 6 (on a 9-point scale) when they foal so that they have sufficient energy reserves for early lactation as well as to maintain condition.

Pregnant mares should have a high-forage diet and should not be overfed starch, or allowed to become underweight or significantly overweight. During the third trimester the foetus accumulates stores of minerals to support rapid growth post parturition. It is therefore important to ensure that the mare receives a balanced diet with respect to vitamins and minerals in addition to providing good quality protein and meeting energy requirements. Good quality pasture or forage may provide sufficient energy through gestation, but might not provide adequate amino acids and minerals. So a supplement such as Competition Horse Supplement from Scientific Nutritional Products can provide a ration balancer to provide the missing nutrients.

Competition Horse Supplement is ideal for broodmares in order to reach their increased need for nutrients, containing over 30 essential vitamins and minerals including calcium, phosphorus and selenium, Vitamin E, A and D.

Horse Supplements Direct manufactures a full range of Horse Supplements equine supplements plus a Glucosamine for Dogs Joint Supplement. To keep up with our weekly blog check out our website or visit our Facebook Page!

For articles and info on equestrian matters please visit . This is the website of the UK’s Pegasus Magazine. Visit to find out more and read articles.

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