Feeding the Good Doer and Overweight Horse

To get more control over what a horse is consuming it is usually necessary to bring the horse off grass completely at first and then longer term, reduce access to grass at key times of grass growth. This cannot be assumed to follow any seasonal pattern anymore due to the changing climate and so vigilance is needed all year round!

There are many factors that affect the nutritional quality of grazing that are beyond our control and the weather is a great example. There are also individual differences in horse and ponies’ appetites with studies reporting that ponies can consume 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!

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 limits 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.

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. 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.

How effective is strip grazing for weight management?

This 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 scores will help to determine this.

Researchers Longland et al (2020) set out to compare three grazing practices on managing bodyweight. All ponies had grass access equating to 1.5% of their bodyweight on a dry matter (DM) basis 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 who were strip grazed. Researchers concluded that strip grazing was an effective management practice for weight loss.

Track systems have 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 or for a long read the full report is here.

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 intake is so difficult to control and nutrient content varies so quickly. For some individuals such as those that are exceptionally prone to laminitis, 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 menège. 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 breathe cleaner air which is beneficial for those with respiratory issues such as RAO. Supplementary forage may be divided up into smaller meals or provided via enrichment slow feeder devices like forage balls and small holed haynets to help make it last longer.

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 mouth and muzzle and has one or multiple holes to allow the horse to consume some grass but limits the amount of grass in each bite.

If we restrict a horse’s access to pasture then alternative forage sources are needed and this is where the issue of providing enough, but not too much, to balance the risk of ulcers but avoid excessive weight gain comes in. Achieving consensus and a clear directive on the minimal dry matter intake for maintaining optimal digestive health has been confused by different studies over the years but the level that most nutritionists would work to and which is also cited by Rendle et al (2020) is 1.5% of bodyweight on a Dry Matter (DM) basis. This is for the long-term management of good doers and is why it is important to weigh your horse’s forage regularly and especially if you change supply or source.

The veterinary perspective may be to restrict intake more than this in an acute scenario to deal with significant obesity, hyperinsulinaemia and laminitis but this is often lost in interpretation and communication. If quantities are reduced below 1.5% under veterinary guidance, the aim should always be to return to 1.5% for the long-term health of the horse.

Soaking hay helps to reduce sugar content but doesn’t necessarily change the calorie content very much so consider having your forage analysed to know exactly what your horse is consuming. This is a service Dengie offers – for more information on the forage analysis services we offer click here. Forages that contain grass varieties such as Timothy tend to be lower in energy and sugar than varieties such as rye grass but analysis will clarify if this is the case for your forage.

As a general principle, it is better to feed more of a lower calorie forage rather than less of a higher nutritional value one if the aim is to promote good digestive health but avoid weight gain. This is why straw should not be dismissed as a forage source for good doers.

Straw often gets “bad press” in the context of gastric ulcers as one study by researchers in Denmark, found that a horse eating straw as the sole or predominant forage source was 4.5 times more likely to have gastric ulcers. What often gets lost when people read this research is the proportion of straw in the ration. In the UK, straw is rarely fed as the sole forage source to horses and so, recognising that straw can be very useful as a low-calorie forage source for good doers, a follow-up study has been published investigating the safety of feeding 50% wheat straw. The research found there was no increased risk of ulcers from using 50% straw to replace haylage in the ration (Jansson et al., 2021).

The rate of consumption of straw mixed with haylage was slower than when haylage was fed alone which resulted in a lower plasma insulin response. Straw has a much lower water-soluble carbohydrate (WSC) content than grass forages so a lower insulinemic response would be expected but, when the rate of intake was slowest in the evening, the researchers found no significant increase at all in insulin levels. This suggests that using low WSC forages and slowing the rate of intake are both important strategies in managing horses with insulin dysregulation (ID) or the potential to develop ID due to being overweight or obese.