Par Audevard, le 15 April 2021

The arrival of spring means the return of good weather and the growth of grass. During the winter, whether your horse is in a stall or in a meadow, its diet is often mainly based on hay. The transition from hay to grass or the arrival of richer grass is an important transition. A few adjustments may be necessary to ensure that your horse's move to grass feeding goes as smoothly as possible and that it enjoys its time outside.

Feed and Grass Transition

The return of the warm weather would make you want to put your horse outside all day. However, it is important to do this gradually, with a minimum of two weeks.

The need for dietary transition when you put your horse out to pasture is linked to the fact that your horse is sensitive to sudden changes in diet. It needs time for its intestinal flora to adapt to a new form of feeding. When your horse is switching to grazing, it will go from a dry forage-based diet (hay, wraps) that is very rich in cellulose to a diet with grass that is lower in raw cellulose and, above all, richer in sugars.

By giving your horse's intestinal flora time to adapt to a new ration, you can avoid problems such as colic or laminitis.

When the dietary transition is linked to a move to grazing, to help the flora adapt, you will need to gradually increase the amount of time your horse is grazing each day. Of course the initial time spent outside will depend on your horse's lifestyle. If it lives in a meadow, the transition will be more gradual because it will be done at the same time as the grass grows. Similarly, if your horse has access to grassy paddocks even in winter, you can make the transition more quickly.

We will take the case of the most significant transition, i.e. a horse that did not consume any grass during the winter, either because it did not go out to the paddock or because it went out to a paddock without grass.

In this case, we advise you to start with low grazing times at the beginning. Depending on the grass availability of the pasture/paddock, you can start with 20-30 minutes for the first few days. Then gradually increase the amount of time spent outside (usually adding 30 minutes each time). Of course, if your horse shows signs of digestive disorders such as diarrhoea or stomach pains, do not continue to increase the grazing time (shorten it if necessary) until the symptoms disappear.

Grazing and sugar levels

It is often said that when horses are put out to pasture in the spring, it is important to pay attention to the sugar content of the grass and that it is essential to choose the right time to graze your horse!

The "sugar" in question is mainly fructan, which like starch is a non-"structural" carbohydrate found in plants. This fructan will have various roles in the plant, including helping it to grow. Fructans are mainly produced when the plant carries out photosynthesis (and thus produces its energy). When these fructans are produced, they will either be used directly by the plant (to grow for example) or stored (more or less long term) and used when the plant is in the right conditions.

Since the fructan rate is directly linked to photosynthesis, it will be linked to the weather (especially sunshine) and outside temperatures. Thus it is considered that fructan levels are highest in spring and autumn.

To understand why fructans can be a problem when putting out to grass, imagine you have a sink. The tap allows fructans to be supplied (via photosynthesis) and the plug removes fructans (during growth). You are then concerned with the amount of fructan in your sink. This is what happens during the year:

  • When the weather is cloudy and temperatures are mild: there is plant growth (the drain is open) and little photosynthesis (tap is closed), the amount of fructan drops.
  • When the weather is sunny and temperatures are cool: there is no plant growth (bung closed) but photosynthesis is working (tap open)
  • When the weather is sunny and temperatures are mild: plant growth is maximum (bung open) and photosynthesis is also taking place (tap open)
  • In the middle of summer, if there is a drought, the plant will not be able to grow (plug closed) but photosynthesis will be significant (tap open). If the drought lasts too long, the plant may die. However, it has time to accumulate fructans before this happens and in this case, even if the bung and the tap are closed, the quantity of fructans stored will be high, (whereas the grass appears to be all burnt out and therefore very poor).

This analogy shows that the risk of fructans is not always the same in different years and that it is important to take into account the weather conditions. This explains why there is a lot of laminitis in spring, as the weather is usually quite sunny (photosynthesis, so the tap is open) but cold (no growth, bung closed).

An excess of fructan (just like an excess of starch) in your horse can lead to different problems. Firstly, as it is energy in the form of sugar, too much fructan can lead to your horse gaining weight. In addition, in horses with metabolic problems such as Cushing's syndrome or equine metabolic syndrome, high fructan levels can lead to laminitis. This condition is often quite recognisable with horses carrying their weight on their hindquarters.

Adapting the ration when the horse is grazing

When the horse is going to have access to grass (daily or for a few hours during the day), the grass intake must be managed as a new food in the ration. We have seen that this grass is made up of sugars, but also of proteins, minerals, vitamins and trace elements. It will therefore be important to adjust the intake of hay, concentrates and possibly the mineral and vitamin supplements according to the quantity (and quality) of grass ingested by your horse.

As far as forage is concerned, you will have to adjust the dry forage intake according to the time spent grazing. For horses that do not go outside continuously and still receive dry feed, we recommend that you put it in before going out. This will allow the horses to eat before they go out and will prevent them from overeating grass when they go out out.

If your horse needs to be fed a concentrate, you will have to think about it. If the concentrate is relatively high in starch, this can cause digestive problems for your horse. We have seen previously that starch and fructan are quite similar, so if your horse is already consuming a significant amount of fructan when it is grazing, you will have to be careful with the starch provided. If you do have to feed a starch ration, we recommend that you avoid feeding it just before going out or just after coming back from the pasture to avoid "adding up" the impact of the starch and fructans.

Some horses are "at risk" when put out to pasture. These may be horses that are "simply" overweight, but also senior horses or horses with certain conditions such as Cushing's or EMS. One of the biggest risks for these horses will usually be laminitis and it may be essential for their good health to limit their grass intake. There are various solutions, which can be combined, to allow these horses to enjoy the outdoors, some of which are listed below:

  • Grazing at-risk horses on poorer pastures (less grass, grass at a later stage of germination and therefore less rich in sugar)
  • Reducing the grazing area if the pasture is rich (locally and temporarily overgrazing, i.e. more horses in a smaller area)
  • Use a basket to limit grass ingestion by horses at risk; ensure that the horse is able to drink as it wishes and does not injure itself
  • Favour night grazing where the grass is generally less rich in sugars and therefore less " risky ".

Monitoring health at grazing time

Often when we talk about putting horses out to pasture we focus on feeding and transition as we discussed at the beginning of this article, but it is still important to continue to monitor your horse's "overall health".

We talk about it often, but your horse's feet need to be watched particularly closely. In the spring, whether your horse has spent the winter in the stall or in the pasture, it will probably move around more. This makes sense for a horse that has been in a stall and is moving from a fairly small space to a much larger space. For horses living in a pasture, many will have reduced their movement in winter, linked to a diet very much centred on one (or more) hay racks. This is why it is important to keep an eye on the condition of your horse's feet, with regular visits to your farrier and/or groom.

It is also important to monitor your horse's overall mobility. It can be a good indicator of health. In case of mobility problems you will be able to react more quickly to certain problems such as abscesses or laminitis for example. If you have any doubts, contact your veterinarian.

Springtime and the start of grassing usually mean that insects and ticks are back. Make sure your horse is as protected as possible from these small pests. The use of a repellent can provide comfort, you can also use a fly cap to protect your horse's eyes (again, beware of injury).

We hope this article on putting your horse out to pasture has been helpful. If you have any questions, please do not hesitate to discuss them with your vet.

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