Feeding the broodmare: the basics you need to know

Feeding the broodmare plays a fundamental role in the success of your breeding project. Depending on the physiological stage, the broodmare will have specific nutritional requirements. Here are a few points to bear in mind to optimise your broodmare's physical condition during the breeding, gestation and lactation periods.

Summary

I. Nutritional requirements at different physiological stages.

1. The reproductive phase.
2. The gestative phase.
3. The lactation phase.

II. The food to choose.

1. Proteins.
2. Energy inputs.
3. Vitamins and minerals.

III. Feeding management at different physiological stages.

1. During gestation.
2. During lactation.
3. At weaning.

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I. Nutritional requirements at different physiological stages.

Generally speaking, a mare in good physical condition should be able to feel her ribs, but they should not be visible. If your broodmare is too thin, her priority is to feed herself in order to survive. The foal could suffer the consequences, suffer from deficiencies or even have a difficult pregnancy.  Similarly, if the mare is overweight, excessive intake can be detrimental to the foal: for example, there is a high risk of OCD (osteochondrosis of development) in the foal.

Your broodmare's needs will vary according to her physiological stage. There are 3 successive phases: reproduction, gestation and lactation.

• The reproductive phase lasts from the time the mare is put to stud until she is pregnant. Her body condition must be optimum to promote fertility. To achieve this, winter supplementation with good quality energy and protein can be useful. A mare in poor body condition runs the risk of abortion and embryonic death.
• The gestation phase should be divided into two periods: during the 1st period, which lasts from the start of gestation until 6-7 months, the broodmare's needs will be different from the 2nd period (from the start of the 3rd trimester until foaling). This difference is explained by the late and exponential growth of the foetus. Nutritional requirements during the first period are similar to those during the reproductive phase.
  From the 6th month onwards and throughout the last trimester, the foetus grows more intensely, crowding the abdomen with uterine mass. As a result, the mare's feed intake capacity decreases (leading to a drop in forage consumption), but particular attention should be paid to protein intake.
  
  

^{Source : IFCE.}

By the end of gestation, a healthy mare should have gained nearly 13% of her body weight.

• A mare's nutritional requirements explode during the lactation phase. Her feed intake capacity increases significantly. In fact, after foaling, the mare's need for energy (known as CFU = horse feed unit), calcium and phosphorus doubles, and her need for protein (known as HDN = horse digestible nitrogenous matter) triples.

II. The food to choose.

1. Proteins

A sufficient supply of good quality protein is essential for the mare and her foal. Proteins are made up of chains of amino acids: some of these amino acids are synthesised by the horse itself, while others have to be supplied via the feed. Lysine and methionine are among the amino acids that need to be included in feed rations, in the right proportions for each physiological phase.

According to INRA, the recommended daily lysine intake for a pregnant mare is 10g/kg bodyweight, and 15g/kg bodyweight for a nursing mare. In the latter case, a lysine-restricted diet will result in reduced milk production for the foal.

You can find good quality protein in a variety of foods:

• legume seeds (broad beans, lupins, peas)
• soya cake (limit the amount of soya cake to 500g per day)
• alfalfa
• and good quality hay (don't hesitate to have your hay analysed for quality!), or even wrapped hay where possible

Breeding feed sellers frequently specify the level of lysine present in the feed, which enables the farmer to know whether the protein is of good quality.

2. Energy inputs

Cereals are mainly used to provide energy for the broodmare: barley, oats, corn flakes, etc. However, it is strongly recommended to monitor starch intake during gestation, as it increases the risk of osteochondrosis and has an impact on colostrum quality. These foods should be used sparingly, and these cereals can be replaced (in whole or in part) by fats such as oil or linseed, which will provide essential fatty acids such as omega 3 and omega 6.

3. Vitamins and minerals.

During the first part of the breeding phase and the first part of gestation (up to the 6th month), vitamin and mineral requirements are no different from those of a working horse. However, if your broodmare is fed only hay, she may suffer from vitamin, mineral and trace element deficiencies. Make sure you feed her properly several months before breeding: a deficiency may take 3 months to correct, and this will have an impact on her fertility. 

From the 6th month and onwards, as the foetus begins to grow, her requirements for calcium and phosphorus (for skeletal development), selenium, zinc and copper (essential for ossification and tissue construction) increase.

> Calcium and phosphorus interact when they are absorbed, so it is advisable not to overdose phosphorus intake (the risk is mainly present in cereal rations based on barley, oats, wheat bran, etc.). 

> Zinc and copper are particularly important at the end of gestation: the foetus will store them in its liver for use in the first few weeks of life. These trace elements help to limit the risk of osteochondrosis in particular. 

> Selenium (like vitamin E) is a powerful antioxidant that should be included in the broodmare's diet from the 6th month of gestation and during lactation. Selenium deficiency can lead to white muscle disease in foals, characterised by stiffness and cardiorespiratory problems. The prognosis is frequently life-threatening in cases of cardiac damage. 

> Vitamins A, D and E are essential during gestation and lactation: they are involved in the reproductive phase, foetal growth and skeletal development.

Do not hesitate to supplement your mare with a mineral and vitamin supplement during each physiological phase (unless another feed provides the contributions listed below). A "breeding" type supplement provides her with the necessary zinc, copper, calcium, selenium and vitamins.

Note: excesses are just as dangerous as deficits for the mare and her foal!

III. Feeding management at different physiological stages.

1. During the gestation.

Below, the IFCE (Institut Français du Cheval et de l'Équitation) suggests a rationing table for a 550 kg sport mare. 

Example for a 550 kg mare at the beginning of gestation (0 - 5 months):

^{Source: IFCE.}

During the first phase of gestation, hay intake meets the broodmare's energy, protein, phosphorus and calcium requirements. Caution: make sure you supplement her with a salt stone + a mineral and vitamin supplement.

Example for a 550 kg mare at the end of gestation (11 months):

Barley-free option:

^{Source: IFCE.}

At the end of gestation, you can opt for a cereal or cereal-free diet. In the first example, hay, alfalfa and flattened barley are fed. In the second case, the barley is replaced by an oil rich in omega 3-6, with the amount of alfalfa adjusted accordingly. It is generally advisable to opt for the second option, to avoid overdosing on starch, which can lead to osteochondrosis problems, as mentioned above.

2. During the lactation.

The broodmare's nutritional requirements explode during lactation and will increase until the second or even third month after foaling (known as the lactation peak). 

Different rations are possible. For foaling at the end of winter, the IFCE proposes 3 distinct cases:

• A ration based on hay combined with traditional feed:

• A ration based on haylage (much more interesting in terms of protein intake) combined with traditional cereal-free feed:

• A ration based on hay combined with a commercial 'breeding' feed: while this solution is the easiest to use (in particular, it avoids dosage errors), it is also more expensive.

Please note: the calcium intakes calculated are generally higher than those recommended: be especially careful not to exceed 2 in your calculation of the Ca/P ratio, which is the case in the examples above. 

In the case of foaling later in the spring, IFCE and INRA have shown that energy and protein supplementation is not necessarily necessary when grazing conditions are favourable. Be sure to add a CMV lick block to meet mineral and trace element requirements.

3. At weaning.

Milk production begins to fall around 3 to 4 months after the foal's birth. At the end of lactation, around 6 months of the foal's life, it is advisable to gradually reduce milk intake, i.e. 4-5 days after the mother and foal separate. The mare's requirements after weaning will then be similar to her maintenance requirements.

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To know / to remember:

> Nutritional requirements change according to the physiological stage of the broodmare, and her intake will need to be adapted over the months to meet her needs and those of her foal. 

> Any nutritional imbalance will have consequences for the health of the mare and her foal, in terms of deficiencies or excesses.

> The quality (and quantity) of protein intake is fundamental: certain amino acids such as lysine in insufficient quantities will have an impact on milk production. 

> During lactation, requirements will differ depending on the foaling period: the diet of a broodmare foaling in February will be different from that of a broodmare foaling in June, as the quality and quantity of grass/forage/wrap varies throughout the spring.

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