How to manage grass intake for horses

Allowing a horse unlimited access to grass seems like the most natural and therefore best way to keep them. From the perspective of the horse, it can allow them to move around freely and potentially offers them the opportunity to interact with other horses. It also allows for a continuous flow of fibre through the digestive tract which we know is important for maintaining gut health. From our perspective, horses at grass tend to be less labour intensive and more cost effective compared to horses that are stabled.

So why would we want to restrict grass intake for horses?

The most common answer to this question is to limit energy (calorie) intake. Managing a horse’s grass intake is fundamental to managing their weight and therefore laminitis risk but it isn’t always easy to do.

Horses in the wild would naturally have a seasonal cycle of weight gain and loss according to the amount and quality of grass available. When the grass is more abundant in the spring and summer they gain weight and then lose it again in the colder winter months so that by the next spring they can afford to put some weight on again. In the domestic environment it is becoming increasingly less likely that horses lose significant amounts of weight in the winter resulting in year-on-year weight gain. This is one of the factors contributing to the obesity problem and its associated health risks in horses in the UK.

The graph below highlights just how significant the energy (DE – digestible energy) intake from grazing can be when the horse has unlimited access to pasture. In the spring months you can see that the DE intake is almost double the requirements of maintenance and so it is no surprise that horses gain weight at this time of year. Winter would usually be the time when energy intake dips below requirements as the grass quality deteriorates. However, over recent years the energy gap between need and supply in the winter months is not as great due to milder winters and continued grass growth. This means weight loss is becoming less likely.

Energy Intake from grazing graph

*DE value for seasonal grass is shown as DE per kg of dry matter

There are many factors that affect the nutritional quality of grazing that are beyond our control such as the weather. There are also individual differences in appetite with Professor Caroline Argo reporting that ponies have been documented consuming up to 5.6% of their bodyweight daily on a dry matter basis. For a 200kg pony this equates to 11.2kg dry matter which equates to 56kg of fresh grass daily and many more calories than they need! Therefore, we have to get a grip on our horse’s grass intake if we want to manage their weight and keep them healthy.

How to manage a horse’s grass intake

There are various methods to manage a horse’s grass intake and ultimately finding a method that is most practical for you and well tolerated by your horse will result in the greatest success. For those on livery yards, managing grass intake can be even more challenging if the yard limit how you can manage your horse. Sometimes there is such a thing as an unsuitable yard for your horse’s needs and whilst it is an upheaval, moving to a more accommodating yard is vital if you are to successfully avoid diseases such as laminitis.

What are the alternatives?

If you can’t limit the area of grazing your horse has access to, grazing muzzles come into their own as the horse can still be turned out in their normal paddock. A grazing muzzle is fitted over the horse’s muzzle and has one or multiple holes to allow the horse to consume some grass but limits the amount of grass in each bite.

How effective are grazing muzzles for weight management?

Research by Dengie’s Nutritionist Tracey Hammond found that the use of a grazing muzzle restricted intake by 75-85% in her study for her Masters Dissertation project. Click here to read about her study.  Later research published by Longland and colleagues in 2011 gave a similar result with a restriction of 75-88%. What was interesting about this second study was that those ponies grazing without a muzzle during the 3-hour grazing period consumed 0.8% of their bodyweight on a dry matter basis, which is over half the daily intake suggested for a dieting horse in such a short space of time. As horses are capable of compensatory eating behaviour when restricted by time, reducing time at grass alone is not a recommended method of grazing restriction for weight management.

grazing muzzle

Why muzzle a horse?

One of the key advantages of a grazing muzzle compared to other methods of grazing management is that it requires no changes to the paddock that the horse is grazing and will be allowed by most yards. Muzzles are quite divisive amongst horse owners and the general public more widely who may not understand why the muzzle is being used. If asked “why muzzle a horse?” we can explain that one of the added benefits is that they still allow the horse to exercise more freely and interact with other horses compared to other methods of grass restriction that reduce the grazing area or require the horse to be stabled on their own.

How to put a grazing muzzle on a horse?

When we’re asked, ‘how to put a grazing muzzle on a horse?’ one of the first things we say is to do it gradually. Don’t expect to put a grazing muzzle on a horse and put them straight out in the field. The more positive you can make the initial training with the grazing muzzle the more likely your horse is to get the hang of it. Start slowly and initially put some grass inside the ‘bucket’ of the muzzle so that your horse is happy putting their head in to eat. Next, when tackling how to put a grazing muzzle on a horse, make sure that it fits properly. Purchasing the correct size muzzle is key and most will also come with a handy guide to help you to adjust for a comfortable fit. The following video discusses how to put a grazing muzzle on the horse and get a good fit. The NEWC have a downloadable leaflet that discusses some of the welfare concerns when using a muzzle that should be considered before putting one.

A common question to the feedline, often from horse owners who are in despair, is ‘how to keep a grazing muzzle on a horse?’ Some horses are very good escape artists and learn how to remove a muzzle adeptly and, in some cases, other horses in the herd will endeavour to remove another horse’s muzzle. Make sure that the muzzle fits and the headcollar is secure on the horse’s head. Some people advocate plaiting a small amount of forelock over the head strap into the mane. It is important that only a small quantity of forelock is used so that if the horse gets caught up with the muzzle and pulls away then the horse can still get loose.

How long can a horse wear a muzzle?

Typically, the advice is that horses wear a muzzle for up to 12 hours, and then are removed from grazing. Longland and colleagues in 2016 investigated using a muzzle for 10 out of a 24-hour grazing period. For some individuals this was successful for weight management, but not for all. Even though 10 hours is an extensive grazing period there is still a chance that horses may compensate once the muzzle is removed. This would be particularly undesirable for those prone to laminitis where insulin dysregulation is a concern. When asked ‘how long a horse can wear a muzzle for?’ we would therefore also advise for up to 12 hours and then the horse should be removed from grazing.

Other methods to reduce grass intake: Strip Grazing

Strip grazing involves significantly reducing the size of the horse’s grazing area by putting electric fencing across a strip of the field. As the grass is grazed, the fence is moved to gradually allow more grass access and to move the grass strip up the field. Some people will also use a back fence and move that at the same time as the front fence to allow the grazed grass time to recover and to keep the total area available to the horse restricted.

strip grazing diagram

How effective is strip grazing for weight management?

This really depends on the size of the strip, how regularly the front of the strip is moved for fresh grass, and environmental factors affecting the growth of the grass in the strip. The grazing area should therefore be adjusted according to whether the horse continues to lose weight. Regular monitoring of bodyweight and fat score will help to determine this.

Researchers Longland and Harris (2020) set out to compare three grazing practices on managing bodyweight. All ponies had grass access equating to 1.5% of their bodyweight DM daily over 28 days. One group had access to all 28 days’ worth of grazing at the start of the study. Another group were given 1.5% of their bodyweight on a dry matter basis daily by moving the front and back fence of a strip and the last group were given access to an extra 1.5% of their bodyweight on a dry matter basis by moving the front fence only. Bodyweight gains were significantly higher for those with free grass access compared to those that were strip grazed. Researchers concluded that strip grazing was an effective management practice for weight loss.

The track system and other alternative grazing methods

The track system has gained popularity in the UK in recent years. A track system can mean different things to different people. For some the track will be completely devoid of grass whilst other tracks may be grass based. The track tends to be around the edge of a field with grazing in the centre for leaner horses or for other uses such as making hay. Resources like additional forage and water are placed in different locations in the track and additional environmental enrichment such as access to sections of hedgerow provided. One of the key benefits of a track system is that it encourages the horse to move more.

Like strip grazing, how successful a track system is for weight management depends on many factors including the size of the track, the amount of grass on the track, and any additional forage provided. Again, this method requires continued monitoring of the horse and adjustments where necessary. Some people with grass on their tracks may then combine a track with strip grazing at times that the grass is abundant.

A recent study has investigated how horse owners are using alternative grazing systems including Track Systems to manage their horse’s health and well-being. A summary of the research can be viewed here.

Reduced grass availability

Another method of limiting grass intake is to try and reduce the amount of grass in the grazing area. Co-grazing with other livestock like sheep, allowing leaner horses access first or even mowing and removing the clippings to reduce herbage a couple of weeks before, are all strategies for reducing the amount of grass available.

No grass area

If you are going to get complete control over what your horse is eating, then a bare paddock is key. This completely removes grass from the equation which is advantageous as grass is so difficult to control. For some individuals such as those that are exceptionally laminitis prone, a no grass area may be a permanent fixture, whilst for others it may just be used tactically such as at times of the year when grass is most abundant. The base to the no grass area can be sand, wood chip or rubber just as for an arena or menage. Do be aware that if the horse is eating forage from a sand base there is a risk of sand accumulating in the gut which may cause colic. As these areas tend to be limited in size, they do have a downside which is the horse isn’t moving around as much. However, if they are outside it may mean the horse can interact with other horses, see what’s going on and breath cleaner air which is beneficial for those with respiratory issues such as RAO.

Whichever grazing system is used, remember to continuously monitor your horse’s behaviour, bodyweight and fat score to assess the effectiveness and suitability of the restricted grazing method.

Click here for further feeding advice or if you would like our nutrition team to review your horse or pony’s current ration.