Nutrition – September 2019

Feeding mares and foals – from birth to weaning:

Planning your approach to nutrition is the best way to ensure a good outcome for both your mare and foal, writes nutritionist LARISSA BILTON.

The birth of a foal is an amazing feat of nature and an exciting time for an owner. Nutrition for both mare and foal plays a very important role in the growth and development of the foal, so ensure you have all the information you need to formulate a well-balanced ration throughout lactation.  

Preparing for foaling: In the weeks before foaling, accustom your mare to the feeds she will need once the foal is born. For an easy-keeper pregnant mare this may mean introducing just a small amount of any new feeds you plan to give her after the birth. Most mares will actually need a larger hard feed during the late stages of pregnancy to maintain body condition and this makes the transition to the post-foaling diet very simple. 

Introduce a DHA rich omega-3 oil such as fish oil or a marine-sourced omega-3 balancer in the last two weeks of pregnancy and continue until the foal is at least two months old. This assists with the mare’s recovery from foaling and provides essential nutrition for development of the foal’s brain and nervous system.  

Changes in nutrient requirements: After foaling, your mare’s protein and energy requirements are higher than at any other time in her life. It is not unusual to have to feed more hard feed, in a more energy dense form, than she has ever needed before. Even when fed as much as she will eat, a lactating mare may still lose weight during the first months of lactation. Unwanted weight loss can be minimised by feeding three or more small hard feeds per day in addition to all the quality hay and pasture she can eat.  

Remember to provide clean water at all times and to make all dietary changes gradually, introducing new ingredients over a two-week period to allow gut microbial populations to adapt.   

Roughage is always the basis of a healthy ration: The first rule of good horse nutrition is to feed plenty of roughage – pasture, hay or chaff.  Unless your mare is overweight, it is safe to feed as much grass-based roughage as she will eat. A lactating broodmare may consume as much as 50% of her daily intake as concentrate.  

Roughage forms the foundation of any well-balanced horse diet. A lactating mare will be experience a demand for energy and protein that’s greater than at any other time in her life. The percentage of the diet provided as an energy concentrate varies significantly depending on horse condition, pasture quality, age of the foal, and horse breed. Unless your mare is grazing a pasture with quite a bit of clover in it, she will usually need a protein supplement to provide adequate amino acids in her milk to support the growth and development of the foal. A quality vitamin/mineral supplement, marine-sourced omega-3s and salt are necessary to top up mineral levels and balance ratios to within optimum ranges.  

Adding the appropriate amount and type of protein: The diets of lactating mares and their foals should include high quality protein rich in lysine, a key amino acid which they are unable to produce in their bodies.  

Lucerne and soybean meal are an effective option for adding lysine to breeding horse rations and are commonly found in commercial feeds formulated for breeding horses. Pure L-lysine can also be purchased and added as a supplement in carefully calculated amounts. Chart 1 shows the increased need for lysine during the first three months of lactation, around four times as much as your mare needed before conception. 

Your mare’s mineral requirements will change too: It is critical to provide vitamins and minerals to satisfy your mare’s daily requirements and to correctly balance the mineral ratios across her entire diet.  

Your lactating mare’s need for some minerals will be higher than during her pregnancy. The main increases relate to the calcium and phosphorous necessary for milk production (Chart 2); as well as for copper, iron and iodine. As with mineral supplementation in all classes of horses, it is imperative that your lactating mare obtains all the minerals she needs in carefully balanced ratios from all food sources. 

Remember to check whether your feeds or supplements contain salt, and if not, add 10g of plain salt (sodium chloride) per 100 kg of bodyweight to the daily ration.  

Do I need to feed a commercial breeding horse pellet?: A top quality breedingspecific commercial premixed feed can simplify feeding if your mare requires the full daily recommended amount of the feed. If she needs more or less calories than the feed provides, adjust the protein and mineral levels to avoid an oversupply or deficiency.  

For this reason, in many cases it can be simpler to provide a protein source and a quality vitamin and mineral supplement separate from the energy source. This allows you to easily alter the diet in response to seasonal changes, as well as your mare’s varying needs through pregnancy to lactation and weaning. 

If I mix my own concentrates, what sorts of feed should I use?:

Extra energy to top up calories from roughage if required. 

  • Super fibres – energy sources that are high in digestible fibre make an excellent basis for adding calories to the diet of broodmares. These include beet pulp, copra, soy hulls, and other legume hulls such as lupin hulls or feeds made from these ingredients. 
  • Legume grains – the most commonly available is lupins. If you buy whole or cracked it is best to soak them in water to soften prior to feeding. 
  • Cereal grains – oats contain starch in a form which is easily digested by horses when fed raw. Oats can be fed whole provided your mare’s teeth are in good condition, but other cereals such as barley, wheat and corn are poorly digested unless cooked (boiled, extruded, micronized or pelleted).  
  • Cereal by-products such as wheat, bran and millrun are lower in energy and nutrients than whole grains. 
  • Fats and oils – can be used judiciously to boost the energy density of lactation diets but must be introduced very gradually to avoid upset. It is important to carefully balance the omega-3 to omega-6 profile of the diet, so choose linseed oil, coconut oil or canola oil and add fish oil or an omega-3 balancer. 

Extra protein to top up amino acids – especially those high in lysine:

  • Lucerne, clover or other legumes in hay or pasture. 
  • Full fat soybean meal has the best amino acid profile to meet horse requirements. 
  • Pure lysine as a supplement. 
  • Other common feeds such as lupins and copra are high in crude protein. 

Vitamins and minerals:

  • A quality vitamin and mineral supplement rich in macrominerals, trace minerals and vitamins. Look for one designed to balance mineral ratios across the whole diet. 
  • Salt. 
  • Consider a probiotic live yeast (Saccharomyces cerevisiae) shown to boost forage utilisation, colostrum quality and milk production.  

Healthy oils: DHA is an omega-3 fatty acid, essential for brain and nervous system development. Also helps with mare and stallion fertility. 

Feeding the foal: It is natural for a foal to copy the feeding behaviour of the mare, so if she will share her hard feed with her foal there is no need to provide a ‘creep feed.’ 

As the foal starts eating more grass, hay and hard feed and drinks less milk, the mare’s feed requirements begin to reduce gradually.  

However, the total amount of food going into the mare and foal unit often stays almost constant until weaning to allow the mare to recover any body condition lost during early lactation, while still meeting the foal’s reduced need for milk.   

When the foal is three to four months of age, provide a portion of the mare’s feed for the foal in a separate container placed next to the mare’s feeder. Over time, increase the foal’s portion and reduce the amount given to the mare.  

Weaning: At weaning, only provide the mare with hay and her vitamin and mineral supplements. Withhold the hard feed for a few days until her milk dries up. Consider giving both mare and foal a live yeast probiotic to support gut microbial populations during the stress of weaning. 

The foal should be allowed free choice access to pasture or grass hay, and a slightly larger hard feed than was given prior to weaning to compensate for the nutrition previously obtained from milk. Monitor body condition carefully and reduce the size of the hard feed if necessary to avoid the foal becoming overweight.  

Feeding an orphan foal: If the unthinkable happens and you find yourself caring for an orphaned foal, seek veterinary advice. Foals need colostrum during the first hours of life. Many breeders will collect and maintain a frozen colostrum store and will often provide some to those in need. Young foals require frequent feeding with a horse milk substitute. 

As the foal gets older, gradually introduce hay, grass and hard feed, doing your best to mimic the amounts a foal would eat from their mother’s feed. Be careful to balance the vitamin and mineral levels correctly. 

Whether your foal is an orphan or feeding from the mare, it can be a wise investment (for your pocket as well as your horse’s health) to seek the advice of a qualified equine nutritionist during these critical stages of life. 

Larissa Bilston (B.Agrsc – Hons 1) is an animal nutritionist. 

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