Supplementing the breeding mare, for the entire season

Supplementing the breeding mare, for the entire season
23 December 2021 | Foran Equine


The key to successful breeding starts long before mating and it has been shown that nutrition plays a big role in the reproductive health of a broodmare. From broader aspects such as body condition, all the way down to specific macro and micronutrients, fertility is influenced by what is fed. 

Protein is made up of non-essential and essential amino acids. The latter cannot be made in the body and so must be provided in the diet. Good quality protein is rich in these essential amino acids, which play important roles in fertility. Studies have shown that mares fed a diet low in quality protein are more likely to suffer fertility problems including an increased risk of failure to ovulate, and the risk of embryonic loss is increased fivefold.  

Another important dietary component are omega-3 fatty acids, which have been closely linked with the reproductive efficiency of mares. It is also known that oxidative damage, caused by naturally occurring particles called free radicals, can have a detrimental effect on egg quality. It is the role of antioxidants to neutralise free radicals in the body, making these compounds extremely important for ensuring good fertility. 

Fresh grass is typically a good source of essential amino acids, omega-3 fatty acids and antioxidants but poor weather conditions in the months leading up to the Thoroughbred covering season often means turn-out is limited and can alter the nutrient profile of the grass that is available. This risks broodmares not consuming optimal levels of essential compounds that support their fertility. Supplementation offers a reassurance that the reproductive health of broodmares isn’t being left to chance, which is particularly important for those with a history of fertility problems or older mares, as fertility naturally declines with age. 

The flaxseed oil found in Kentucky Karron Oil is a rich source of omega-3 fatty acids, with the additional benefit of being emulsified, improving bioavailability. 

V.S.L. Liquid supports fertility by providing a rich source of vitamin E and selenium, both renowned for their antioxidant properties, as well as essential amino acid, lysine. For even more advanced support, For-Repro Mare delivers omega-3 fatty acids, vitamin E and selenium, plus the most bioavailable form of CoQ10; ubiquinol. This molecule is a powerful antioxidant and is also required to produce cellular energy – especially important for maintaining healthy eggs. 


The nutritional requirements of pregnancy grow as the foetus does. Everything that the foal requires must come from the mare and she must also consume enough to meet her own needs, as her body changes. Although foal growth is slow early in pregnancy, it is important to ensure the mare’s reserves of essential vitamins and minerals, such as calcium and phosphorus, are maximised in preparation for the more rapid growth in the third trimester. This is particularly important in older mares, who are naturally less efficient at absorbing calcium. 

In addition to supporting growth and development whilst still in the womb, the nutritional status of the mare affects the foal after birth too. Foals have developed the clever nutritional strategy of storing trace minerals, such as copper, zinc and manganese, in their liver, before birth. This is because mare’s milk is quite low in these elements. Without proper stores of trace minerals, the young foal may be predisposed to bone development disorders and any shortfalls at this stage cannot be made up by supplementing the foal after birth.  


Cal-Gro provides calcium and phosphorus at the ideal ratio to optimise foetal bone development, as well as essential minerals including manganese, zinc and chelated copper (for optimal absorption), to support the mare and developing foal throughout pregnancy and beyond. 


Other than perhaps a racehorse in training, a lactating broodmare has greater nutritional needs than any other class of horse. Lactation is a time of recovery, production and preparation, as the broodmare continues on her reproductive cycle.  

If her nutritional needs are not adequately met, a broodmare will experience loss of condition and mineral store depletion, with potentially devastating effects on her physical health and future reproductive performance. Of particular note, is an increased requirement for calcium and phosphorus to replace losses from the foal’s high requirements during pregnancy. 

Her needs aren’t the only ones that must be considered though. The foal remains reliant on the mare’s milk to meet its nutritional requirements until weaning, so everything the foal needs for healthy growth and development – i.e. high-quality milk, rich in protein and fat, in sufficient quantity – comes from what the mare is fed.  

Unlike other calcium supplements for horses, Cal-Gro not only contains calcium and phosphorus in the ideal ratio of 2:1, it also includes the essential amino acid lysine, chelated copper, zinc and silica – all of which help optimise the nutritional content of milk. 

Omega-3 fatty acids which predominate in mare’s milk, cannot be produced by the body and are very low in hay and grains. It has been shown that adding fats to the diet of lactating mares can improve the fat content of their milk, so supplementation can be a great way to maximise the chances of quality milk-production. Kentucky Karron Oil is an excellent addition to a mare’s diet to support milk production by supplying superior quality essential omega-3 fatty acids in a highly bioavailable format.   

There is no point having a perfectly balanced diet if a brood mare doesn’t eat it. The post-birth period, with the challenges of recovery and a brand-new foal to worry about can see some broodmares go off their food. It is therefore often worth going to extra lengths to encourage food intake during lactation. B-Complete is a palatable, vanilla flavoured liquid B-vitamin supplement to help support and promote appetite. It also contains a prebiotic to aid digestion. 

For more advice on targeted supplementation to support the reproductive health of broodmares, speak to one of our advisers