Welcome to the Trickle Net Forage Feeding calculator

The importance of considering dry matter intake (DMI) on pasture

Estimating dry matter intake (DMI) on pasture is important, but also very difficult because the amount a horse or pony will consume will vary between individuals, as well as between pastures.

Some factors which may cause variation in DMI between horses on the same pasture include:

• Breed: A Welsh section A is capable of 5.4% of bodyweight (BW) DM, whereas a TB will eat closer to 2.6% on the same pasture. 5.4% BW DMI will cause rapid weight gain, which is why alternative grazing systems are essential for native breeds.


• Health: Dental problems or health issues which can affect appetite may reduce intake


• Energy requirements: A horse or pony in hard work will increase the amount of DM he or she eats. However, an inactive horse or pony will not reduce the amount they are eating to prevent weight gain.


• Hours with access to grazing: A horse or pony will change their grazing pattern, and the amount of grass they eat depending on how long they typically spend at pasture. For example, a pony is capable of eating 1% BW DM (so 50% of his daily requirement) in just 3 hours if he is restricted to 3 hours of pasture access per day. This is because he will prioritise all this time for eating, instead of resting or socialising.

Some factors which might change how much a horse can eat while grazing include:

• Pasture quality: Lush grass can be eaten far more quickly than short grass or old stemmy grass


• Pasture type: A mixed species of grasses may encourage a horse to forage around for the more palatable species, slowing down intake


• Individual or group turnout: Group turnout will encourage move movement and socialisation. A higher stocking rate (more horses on one field) will also help to reduce the amount of grass available for each horse to eat.


• Grazing management system: The use of tracks and other alternative grazing systems will encourage movement and foraging behaviours, while discouraging binge eating.

Our calculator aims to give you an approximation of DMI from pasture, based upon the current research available. It is key to have some understanding of grass DMI when considering a weight management plan for your horse. The calculation here is based on horses grazing three types of pasture with data averaged from the following research: Poor- 1.32-1.62 % BW/DM/day (Harrison, R, and Murray, J.M.D.,2016)
Average - 2.2% BW/DM/day (NRC,2007)(widely accepted)
Lush: 3.2-5.4% BW/DM/day (Smith, DG, Cuddeford, D, Mayes, R and Hollands T).

This calculator does not factor in the increased rate of grass consumption caused by limited turnout time.
Owners need to be aware that native types are capable of eating over 200% of their daily requirements with free access to good grazing, resulting in considerable weight gain. It is also important to appreciate that simply reducing the hours they have access to the good grazing may not reduce the DMI sufficiently, as the horse or pony will simply spend more of the time spent at pasture eating.

Where significant weight loss is required we recommend a consultation with an Equine Nutritionist. They will be able to advise how best to modify your grazing system alongside forage feeding to facilitate weight loss, while ensuring your horse or pony does not spend hours without access to food, which could increase the risk of other issues such as gastric ulcers and stereotypic behaviours.

Restricted diets at 1.5% BW should always be considered temporary, and a management strategy should be used to prevent long periods of hunger and boredom. Please seek advice if you need some support with this. We can help.

Always consult your vet if you are concerned for your horse's health.