Equine Nutrition Part 1: Grass and Pasture Management

With all of the rain we have had this spring, the lovely green stuff our horses crave is in abundant supply. However, how you manage the grass your horses consume during the peak growing season can affect their nutritional intake. When deciding how much grass for which horses and when, here are a few points to consider:

  • Nutritional Value: Grass provides horses with carbohydrates, protein, vitamins and minerals. The quantity and quality of these nutrients depends upon the time of year, the temperature, pasture management and grass species. If you manage your own pastures, you may want to have your soil tested or have a sample of grass analyzed for nutritional value.  Colts Head Veterinary Services can perform this service.
  • Introducing Horses to Grass: Horses should always be introduced to grazing gradually. This gives the microbes (bacteria, fungi, and protozoa) in their large intestine time to adjust. Typically, you should allow a total of three weeks to make a gradual transition onto full turnout.
  • Metabolic Disease: Horses who suffer from insulin resistance or Cushing’s disease have a decreased ability to digest carbohydrates. These horses can be particularly sensitive to grass, where the levels of carbohydrate can vary greatly. Some horses with these diseases are best kept off of grass completely or limited to less than 1 hour of grass a day to avoid unwanted side effects (such as laminitis). Note: Under some circumstances, horses with metabolic disease can be allowed limited access to grass. Contact your vet for more information or if you have questions.
  • Overgrazing: The best strategy for avoiding overgrazing is to rotate your available pasture space. Even if you do not have a lot of land available for grazing, divide up what you do have into at least two sections, which helps the grass to stay healthy. Horses can safely graze horse rotational grazing blogstarting when grass is 6 inches tall and coming off the grass when it’s below 4 inches.  In peak growing season, you should rotate your horses between pastures about every two weeks. However, this time frame will depend on the number of horses and the size of pasture available.

In certain situations, full-time access to grass, along with a mineral salt block and fresh water, can completely make up a horse’s diet. Age, lifestyle, metabolic disease, dental health and the amount of pasture available can all influence whether additional feedstuff, such as grain and hay, are needed as well. Assessing your horse’s body condition score is a great way to ensure that they are getting enough – and not too much – forage in the way of grass.

This is the first in a two-part series on equine nutrition highlighting forage for horses. Part two will look at hay.