Horses breeding season
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28 April 2020

Pregnancy: the dietary needs of the pregnant and lactating broodmare

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How long is the pregnancy in the horse?

The mare pregnancy lasts an average of 340 days, with changes considered normal between 320 and 370 days. The foals born before 320 days require veterinary assistance, while those born before 300 days hardly survive. It has been shown that the size of the foetus is reduced when the final phase of the pregnancy coincides with the winter months and this has an impact on the growth of the foal during the first three months of life. In nature, in fact, foal’s birth takes place in spring, but for the competition, horse oestrus and the fecundations are anticipated to obtain birth in the first months of the year. In this way, colts and fillies can be premature trained and thus make an early start in sport events.

How does foetal development affect requirements?

During the first 4 months of pregnancy, the development of the foetus has little influence on the mare needs and if in good shape, it may continue with a maintenance ration.

broodmare supplement

From the 5th month of pregnancy, the foetus will have a sudden and imposing development that will considerably increase the nutritional needs of the mare. It is necessary some gradual changes in the broodmare diet to ensure that its needs are met to support the last part of pregnancy by giving birth to a foal in good condition and that the mare itself can produce good quality milk.

The growth of the foetus occurs mainly in the 2 months preceding the foal birth, however, several studies have shown that the energetic needs of the mare increase already from the 2nd trimester of pregnancy due to the development of the placenta. It is, therefore, necessary to increase the energy since the 5th month of pregnancy, with greater increases in the last trimester. Protein requirements increase as pregnancy progresses as all tissues (uterus, placenta and foetus) require more bioavailable nutrients during gestation. Every day, in fact, the development of the foetus and the placenta subtracts to the mare 80 g of proteins, but also 7-8 g of Calcium and 4-6 g of Phosphorus.

How can energy needs of broodmare be met?

broodmate feeding needs

In the last two months of pregnancy, the foetus takes up a large part of the abdominal cavity, so the mare is not able to ingest a high quantity of dry matter. Increasing energy by giving large amounts of forage is almost impossible, due to the space.

The best choice is to administer cereals or specific complementary feed rich in noble proteins and proteins. The last ones are to be preferred, to avoid mistakes in energy balance and supplementation. For these reasons, it is recommended to administer a balancer with high protein content (27%) like Mac Breed. This way, among other things, has the advantage of getting used to the mare to the diet that will be administered during lactation.

Try it on your broodmares during pregnancy >>> https://www.equiplanet.it/prodotto/mac-breed/

If you prefer not to make changes in the mare diet and continue to use a basic feed or a cereal mix, we suggest adding a mineral feed such as Osteo Foal (shop now!), able to cover vitamins, minerals and amino acids requirement, adding 4 grams of lysine per daily amount.

How can energy requirements of lactating mare be met?

A well-fed broodmare with a good genetic level, produces between 15 and 20 liters of milk per day, depending on its size. In 150 days, for example, an English Thoroughbred mare can produce about 1700 litres of milk.

lactation requirements

The lactation peak is reached during the first month and during this phase, the broodmare needs 48 g of protein, 2.4 g of calcium and 1.5 g of phosphorus for each kg of milk produced. Besides, the mare energy needs may double those of maintenance. It is wrong to assume that once the mare gives birth, it can return to normal feeding regimes, indeed it is during this phase that she needs energy: about 1700 kcal per kg of milk produced.

In the 3rd month of lactation, milk production decreases and can meet only 50% of the foal needs and from the 4th month only 20-25%. The foals that do not have supplementation with complementary or mineral feeds, deplete the reserves of the mare and despite this, they cannot take all the amino acids, vitamins and minerals to grow properly. When milk becomes poor, before weaning, integration with Osteo Foal is recommended, not only for lysine and methionine that improve the protein content but also for calcium and phosphorus in a balanced way.

Try Osteo Foal during pregnancy https://www.equiplanet.it/prodotto/osteo-foal

The rations mainly based on cereals exceed the phosphorus intake, which can hardly be compensated by the Calcium content in the forage. Excess of Phosphorus prevents the absorption of Calcium causing the most common orthopaedic developmental problems. Finally, to promote the absorption of Calcium it is necessary to supplement the diet with Vitamin D, also contained in this mineral powdered mineral feed formulated by Equiplanet.

The use of Osteo Foal is advised in the foal at least until one year of age, just to counteract the onset of nutritional deficiencies leading to morpho-functional alterations of the skeletal and cartilaginous apparatus, which all breeders avoid.

foal feeding requirements


  • Introduction to Horse Nutrition, First Editio. Zoe Davies, 2009
  • Problems in Equine Nutrition. Pagan JD, 2004
  • Effects of season on placental, foetal and neonatal development in horses. Beythien E,  2017
  • Horse Owner’s Veterinary Handbook, second edition. Gore, T, Giffin, P, Adelman, JM, 2008
  • Equine Nutrition and Feeding. Frape D, 2010
  • Equine uteroplacental metabolism at mid- and late gestation. Fowden AL, 2000