Grassland management for the obese horse
Briony Witherow BSc MSc RNutr. PGCERT FHEA, discusses the long and the short of it
If you care for a good doer and aren’t already restricting grazing, you will be starting to think about it for the summer months.
Typically, the end of March marks the start of a rapid increase in grass growth known as the spring flush.
Depending on your success with winter weight loss, proactive grassland management for the good doer in the UK often starts at this time (depending on the weather, management of pasture over the winter months and grazing area) – and for some even this isn’t soon enough!
Weight gain at this time of year seems to sneak up on us, often due to the misconception of there being no grass and, before we know it, we have an obese horse. However, there is always more grass than there appears and, employing methods to emphasise this and get your ‘eye in’ early in the grass growing season can be invaluable.
So how do we know when to start restricting grazing?
There are various indicators, which we can use as horse owners to prompt changes in how we manage our good doers. Whether you prefer an analytical approach of having a ‘test patch’ near your field that you monitor, keeping an eye on your back lawn, weekly monitoring of weight and condition or, keeping tabs on when your horse is starting to nibble the grass in preference to his hay or haylage – all can be effective to some extent, and even more so when used in combination.
The key is to employ these early enough in the year and to act swiftly with proactive management changes.
Who should have their grazing restricted?
When it comes to restricting grass intake, this isn’t just for good doers. There are many other reasons why we might limit or manage pasture access, including clinical issues like Equine Metabolic disease and Cushings (PPID) along with muscle disorders like PSSM or recurrent bouts of coli ¹⁻⁶. In fact, many horses require some sort of pasture restriction at some point throughout the year. For horses with metabolic concerns, it is important to consider that even if body condition and weight is well managed, pasture management to limit sugar intake is still ¹⁻⁶.
The fundamentals of pasture restriction
When it comes to pasture restriction there are several factors that we are looking to control and, when managing the good doer, both factors should be considered.
Sugar levels and subsequently the potential for calorie consumption
Unfortunately, there is never a one-size-fits-all answer to pasture ⁷ ⁸ and therefore some trial and error may be required to find the right solution for your horse, detailed below. There are, however, some fundamentals, upon which we can base our approach, along with common pitfalls and some grey areas. The first crossroads many of us meet when considering pasture restriction is whether to graze very short grass (essentially over-graze) or whether there are greater benefits in grazing longer grass.
Short grass: the stress factor?
When we look at how plants function, some basic facts exist – if a plant is under ‘stress’ - whether that be from over-grazing, drought or a lack of nutrients in the soil - the result is higher water-soluble carbohydrate (sugar) accumulation ⁹ ¹⁰ ¹¹ – Meaning more sugar per mouthful for our horses.
So, where grass is grazed close but importantly not to the point where the grass is permanently damaged, the horse is repeatedly taking the newest growth (which is under stress) and therefore likely to be high in sugars and ultimately calories (and low in fibre). But crucially with this approach, while the sugar levels (and therefore calories) are not controlled, you are able to restrict overall QUANTITY consumed.
It should be noted that where the area grazed is so small that the horse is grazing faster than the grass is growing, this will, over time, result in permanent damage to the sward and ultimately degraded bare pasture, which is itself another option.
So, is longer grass the answer?
In many cases no, but for some, yes.
When grass is actively growing and under less stress (not over-grazed), that the grass is often lower in sugars (providing it has not gone to seed)⁹ ¹⁰ and higher in fibre. However, there is a catch. As the grass is typically longer, the horse can take a larger mouthful meaning that he typically consumes more. This, unfortunately, often ends up ruling out any benefit of the lower sugar content and again, may result in an obese horse . One solution to this is to use a grazing muzzle however, if left unrestricted longer grass may control sugar but, does not control quantity. In fact, it could be argued that this type of grazing actually presents more risk in terms of overall calorie consumption due to the likely larger quantity.
It is really down to the individual ⁷ ⁸. We know that turning out for a shorter period of time can lead to compensatory grazing¹² (the horse/pony eating more to make up for lost time) and is therefore ineffective, so what are our options?
Graze close (short) BUT not to the point of sward damage
This can reduce overall quantity consumed by reducing bite size BUT this could come at the risk of not meeting minimum fibre requirements (young grass being less fibrous ¹³ ¹⁴) and crucially, not satisfying the horse’s appetite (which is linked to dry matter intake rather than calories consumed ¹⁴). The result of this? A hungry horse and potentially an unhealthy digestive tract.
There are also long-term considerations for this approach, and special care must be taken to monitor dentition and, those on sandy soils should monitor sand consumption and take proactive steps in managing this.
In an effort to satisfy both your horse’s appetite and gut function, ensure that you supplement this type of grazing with a high fibre (late cut) hay/haylage potentially alongside straw, (at a maximum 30% of the forage ration).
Remove grazing from the picture altogether
If you are looking for complete control over what your horse eats, the only answer is a complete removal of grass from the equation. Grass intake is very difficult to estimate and regulate and for those at the extreme end of the weigh scale, or with complex or ongoing clinical issues, sometimes this is the only choice.
Along with exercise, this can be the approach required to kick start a weight loss programme. You should however, for the individual’s well-being, allow for some change in scenery and couple stabling, with turnout on a bare or woodchip paddock alongside a suitable low calorie forage source, such as late cut forage (ideally soaked and or steamed).
Use a grazing muzzle
While it should be accepted that grazing muzzles do not suit all horses and all situations, they can be an excellent solution for some. In fact, when successful, they often achieve something close to ideal for the good doer - providing an opportunity to burn some calories by promoting movement and facilitating a trickle feeding of food through the system through essentially restricting bite size ¹⁵ ¹⁶.
Be sure to introduce these gradually and adhere to best practice regarding appropriate length of grass for use (typically a minimum of 2 inches) and maximum duration of wear (no longer than 10-12 hours per day)¹⁵ ¹⁶. If you are struggling to get a good fit, shop around! There is a huge range of different muzzles available to suit all different shapes and sizes – take time to find one that suits your horse, make sure you learn how to fit it correctly and, that the horse has worked out how to eat and drink through it, before you leave h.
Regular monitoring, reviewing of progress⁷ ⁸ and, how your horse/pony is coping with the chosen pasture restriction is key, along with regular dental checks which are essential, especilly where natural grazing behaviour and technique is altered in any way.
For pasture restriction to work, any method to limit intake should not be employed alongside free access to grass ⁷ ⁸. When not at restricted pasture, instead the horse should be stabled or restricted to a dry lot, where a suitable hay/haylage can be provided.
Join us next time for practical tips on reducing sugar intake from grass, examples of different grazing systems to try with an emphasis on the bigger picture of satisfying appetite, promoting activity and opportunity for socialisation.
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