Preparing broodmares for autumn and winter

How do you know if your mare is too fat or too skinny? And how can you improve your horse´s condition?

Normally, horses have stored a surplus of fat over the summer months that can be used during the cold winter months. But are these reserves sufficient to see them through the winter?


Your broodmare´s condition is of key importance. This is true for empty as well as pregnant mares. When they are in good physical condition empty and maiden mares have a better chance of developing normal cycles than when they are obese or underweight. Similarly, mares in good condition during pregnancy and foaling will be easier to rebreed.

Your horse´s condition can easily be assessed with the help of the Body Condition Score (BCS). This BCS gives you an idea of the amount of fat deposited under the skin and whether your horse is too fat, too skinny or just in the right condition.




How can you calculate this Body Condition Score?

Owners can do this themselves by feeling and evaluating the amount of fat on the ribs, along the neck and spine, and behind the shoulder. This helps to give your horse a score ranging from 1 to 9, as shown in the table below. A horse with BCS 1 is far too skinny, one with BCS 9 is obese.


The desired BCS for broodmares is 5 or 6, because mares that enter the breeding season with a score of 1 or 9 are likely to have reduced reproductive efficiency.

So ideally, in a horse with good condition you can feel and slightly see the ribs. In addition, these horses have enough fat cover over their toplines so that the loin area is relatively flat. Their necks are not too thin and have a smooth transition to the shoulder. With a BCS of 6 or higher the ribs can neither be seen nor felt  and the horses have so much fat along the spine that a crease can be seen on the loins. If the Body Condition Score is too low, the ribs and the spine are clearly visible.

Mares with foals as well as mares that were used for competition activities during the summer often drop in condition to scores below 5 in autumn. These horses need extra nutrition in the autumn to ensure they are in good condition again for the next breeding season or foaling.

Opposed to these mares, those mares that have had rich grazing all summer and autumn might have scores above 7. This can cause an increased risk of for example laminitis or colic. For overweight horses the winter months are ideal for losing weight: the pasture is less nutritious and in cold temperatures more energy is consumed.

Pasture and hay

When the quality and quantity of pasture decreases, mares´ rations must be supplemented with hay. In dry summers, like we have experienced in recent years, it is probably even better to start giving hay in July and August.

If your mare´s body condition score drops it is likely the nutrients she is ingesting are not sufficient. In the case of overgrazing (too many horses for the size of the field) the advice is to supplement with hay. Overgrazing in the autumn also tends to weaken the grass and reduce its growing power for the next spring. This gives weeds a chance to spread across the field.

An easy test to find out if extra hay is necessary, is to put some hay in the field. If the horses ignore the hay, this is a sign the grass is meeting their forage needs. If however, they quickly eat the hay it´s clear they need it to stay in good condition.

Have your hay analysed! According to veterinarian Frederik Mijten, broodmares can get through the winter on hay alone, provided the hay is of good quality. This is why it is important to have your hay analysed on a regular basis so that you know what you are feeding. On the basis of this analysis your horse´s ration can be adjusted by supplementing proteins, for example alfalfa, minerals or vitamins. If you produce your own hay, it´s also a good idea to have your field analysed from time to time. A soil analysis offers you an opportunity to improve the quality of your hay. Analyses of soil and hay are not expensive and can prevent other additional costs.

The next question is: how much hay does a horse need in autumn and winter? In a UK study mares were given around 1 kilo of hay per 50 kilos of body weight. That comes down to about 11 kilos of hay per day for an average-sized mare. Please note, this figure represents the amount of hay actually consumed by the mare, and not the amount of hay given. Some of the hay will be wasted so the amount fed should be slightly more than the amount to be consumed. Moreover, the mares in this study received only a small amount of concentrates. Mares that are fed larger rations of concentrates will need less hay.

Concentrates/hard feeds and Supplements

In addition to pasture and/or hay, broodmares are usually fed a commercially-produced hard feed or supplements. The term hard feed or concentrates refers to a feed that is a concentrate of pelleted calories. Common hard feeds, such as oats, corn and other cereals are good energy sources but have low contents of calcium, vitamin E and other necessary nutrients. Commercially-produced hard feeds however, usually contain a supplement of nutrients in addition to cereal grains. Hard feeds are added to the mare´s diet in case the amount of roughage does not supply the mare with sufficient calories. Most mares need hard feeds in the last phase of gestation. Mares from small, thrifty breeds usually get smaller amounts of hard feeds in late gestation.

Supplements are a source of vitamins, minerals and sometimes proteins. These are given in small quantities (generally half to one kilo per day) when the mare is getting sufficient calories from grazing or hay. An example: if the mare can maintain a condition score of 6 on the basis of just grazing or hay, then she needs no extra calories in the shape of hard feeds. What she does need are the numerous minerals contained in a supplement. For mares whose BCS is too low when on a ration of just hay, it is advisable to give an extra commercially-produced hard feed or a common hard feed in combination with a supplement.

Summarising, we can say that hay can be sufficient to get through the winter, depending on the quality of the hay. Often however, a nutrient analysis shows that extra feeds are necessary, consisting of alfalfa and or nutritional supplements. Fact is that there is no absolute formula: it´s the master´s eye that feeds the horse.

De-worming and vaccinations are a must.

Something else that should not be overlooked in winter is de-worming of your foals and other horses. Best practice is to do this in consultation with your vet because there are countless analyses and schemes on de-worming to be found on the internet. The de-worming scheme depends on several criteria, for example age, number of horses in the field, resistance development,… In addition to routine de-worming, which is 4 times per year, it is good practice to carry out worm egg counts on a regular basis. This is a way to find out if your mares have developed a resistance to a specific worming agent.
And understandably, there is an increased chance of a worm infestation in poor pastures with only 2 cm of grass compared to rich fields with grass stems as long as 20 cm. Towards the end of summer or in the autumn when there´s less grass in the field your foal/horse has a higher risk of contracting worms. De-worming is an absolute must when horses are brought in for the winter.

In addition to de-worming, vaccinations are also important for your broodmare. This way the mare can produce antibodies against the diseases for which she has been vaccinated. These antibodies are passed on to the foal through the milk so that the foal is also protected. You are advised to have your mare vaccinated annually against Influenza and Tetanus and to repeat these vaccinations one month before foaling. Pregnant mares must also be vaccinated against Rhinopneumonitis. This should be done at 3, 5 and 7 months after the time of insemination.

Lastly, it is advisable to give your horses an overall health check when winter arrives. Think for instance of your horse´s teeth. Bad teeth hamper the intake of food and can cause many problems. So this is why the teeth should be checked by a veterinarian or equine dentist every two years. Don´t forget the feet either, ideally, these should be trimmed every eight weeks. For foals too it is advisable to consult a farrier to avoid the development of deviating stances.







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