Category Archives: Nutrition

Equine Nutrition Part 2: Hay

collecting hay sample

Dr. Parisio collecting a sample with a hay corer.

For many horse owners in this area of New Jersey, hay remains the largest forage source available.  Most horses should consume 2% of their body weight in forage daily.  This equates to the average 1,000 lb. horse typically eating as much as 20 lbs. of hay per day.

Given that hay comprises the largest and most important component of a horse’s diet, knowing the nutritional quality of this forage source is essential.

What to look for when buying hay

Characteristics to look for when assessing the quality of hay:

Leaf-to-stem ration: For most horses, hay with a high leaf to stem ratio is most desirable.  An indication of the maturity of grass when it is cut, younger, leafy grass hay contains more protein, energy and minerals than hay cut later in the growing period.  The higher the proportion of stems, the less digestible and therefore less desirable hay becomes.

Fresh smell and appearance: It is wise to always inspect the hay with your eyes and your nose before feeding it to horses.  Hay should not be yellow or brown in color, which could indicate that it is too mature or has been stored properly.  A moldy or sweet smell could indicate spoiling of the hay during storage.

Dust: If you shake out a flake and a dust cloud appears, making you want to sneeze, imagine what this can do to your horse’s respiratory tract!  Dusty hay is often the first trigger in chronic inflammatory airway disease in horses.

Examining your hay to assess the above qualities is an important first step.  However, the actual nutrient quality of the hay is much more difficult to determine.  There are several factors that can significantly impact the nutrient quality of hay and furthermore, your horse’s ability to obtain those nutrients.  What is the best way to find out?  Having your hay analyzed.

This process includes obtaining core samples of a representative portion of your total hay supply.  These samples, along with information on the type of grass hay and the cutting (1st vs. 2nd etc.) are sent to the lab for analysis.  The results are reported and interpreted as follows to highlight the most important nutritional qualities of hay:

Crude Protein: Protein is required on a daily basis for growth, maintenance, lactation and reproduction.

Neutral and Acid Detergent Fiber content: These measurements tell us how digestible the hay is. The higher these numbers are, the lower the digestibility of your hay.

Carbohydrates: Represents the amount of energy (starch) and other forms of carbohydrates in the hay.  Higher values may be unsafe for horses with metabolic disease, those who are obese, or who suffer from laminitis.

Minerals: Calcium, phosphorus, potassium, copper, and zinc are just some of the minerals we consider important in a horse’s diet.

Vitamins: Vitamins A, D, and E are all components in hay that horses need to stay healthy.

hay sample

A hay sample ready for analysis.

For most horse owners, hay will be the largest and most important expense factored into the daily care of their horse each year.  Therefore, it is essential to know that what you are buying and feeding to your horses is indeed of the quality you expect.  Whether you choose to have you hay sampled once a season or once a load, whether you share the information with multiple horse owners at a large barn, or stay informed about your own supply only, the analysis can provide information on how to feed your hay efficiently while adequately providing for your horse’s nutritional needs.


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.