How Much Hay Will My Horse Eat in 1 Year?

An equine nutritionist explains how to calculate the amount of hay your horse eats annually and how to reduce hay waste to stretch your budget.

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round hay bales in field
Buying hay in bulk can help you save money. | iStock

Q: Hay is expensive in my area, so I must plan purchases in advance. How do I know how much hay my horse needs for the year? What tips or tricks do you have for minimizing wastage and ensuring my horse gets the nutrients he needs?

A: Purchasing hay in bulk can be a fantastic option for many facilities. It ensures you not only have enough hay for the year but also a consistent, unchanging source of hay for your horse.

Calculating How Much Hay to Buy Your Horse

The gold standard practice is to weigh your horse’s hay. You can use a luggage or fish scale to easily weigh your horse’s hay each day. However, this is not realistic for most owners, so you might need to estimate the amount your horse consumes.

To do that, you need to estimate how much each horse needs to consume; horses should eat about 2% of their body weight in dry matter per day. However, many horses consume more than this when given free-choice access to hay. You can restrict an overweight horse to less than 2% but, as an average, I recommend using 2.5% of their body weight to calculate how much hay you will need for a year. Please note that if your horse also consumes commercial concentrate products or fiber sources such as hay cubes, he’ll eat less hay decrease because those products also contribute to daily dry matter intake.

There are a few different methods for estimating the weight of a horse. In an ideal world, every barn would have a scale to collect accurate weights on the horses, but this is rarely possible. Measuring heart girth and body length or using a weight tape (less accurate) can help you accurately estimate your horse’s weight. Please note that if you have a pony or a growing horse, the mathematical equation differs.

When calculating how much hay to purchase, consider hay wastage during storage and feeding. The amount of waste varies greatly depending on the type of bales and the feeder you use. For example, hay wastage can range from 1% to 13% when using small square bales in varying feeder designs. Hay wastage can exceed 50% when feeding round bales with no feeder. So, when calculating how much hay you should buy, first measure your horse’s weight and consider his daily consumption, then calculate how much waste you can expect.

Here is an example of a conservative estimate calculation for a 1,000-lb horse:

1,000 lbs body weight x 2.5% body weight = 25 lbs of hay per day consumed

25 lbs x 365 days = 9,125 lbs of hay consumed for the year

Once you estimate what your horse consumes, you need to account for hay waste, which will depend on how you feed the forage. If you use a slow feeder, hay waste will be significantly less than if you feed it directly on the ground. For the sake of this example, let’s say 5% is lost in storage and 3% is lost when feeding (assuming you use a slow feeder).

9,125 lbs x 1.03 (feeding waste) x 1.05 (storage waste) = 9,868.7 lbs required

If each bale weighs 40 lbs, divide your total by the average bale weight to get the number of bales you need.

9,868.7 lbs of hay / 40 lbs per bale = 246.7 bales, so you should buy 247 bales for that horse for the year. Remember, you must calculate this amount for each horse.

Minimizing Horse Hay Waste

As you mention in your question, hay is expensive. Have it analyzed to be certain it meets your horses’ nutritional needs. In addition, if your horses waste more than 10% of their hay, it can have a significant impact on care cost. A quality hay feeder is an investment, but if you calculate how much hay you need to purchase, and how much waste occurs both with and without the feeder, you might find the feeder pays for itself within one year.

Choose a feeder that keeps hay off the ground and reduces the horse’s ability to grab large mouthfuls because this often results in dropping and wasting hay. Because you feed small squares, evaluate the various slow-feeding options to find one within your budget that seems like a good fit for your horse.

Take-Home Message

When calculating how much hay to purchase for your horses, you need to estimate how much they eat and waste per day. With this information you can estimate the number of bales you need to buy for one year. Introducing a slow feeder can help reduce hay waste and, thus, the amount of hay you need to purchase, saving you money in the long run.

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Written by:

Madeline Boast, MSc completed her master’s in Equine Nutrition at the University of Guelph and started an independent nutrition company known as Balanced Bay. She has worked with a variety of equids—from Miniature Ponies to competing Thoroughbreds. Boast designs customized balanced nutrition plans that prioritize equine well-being, both for optimal performance and solving complex nutritional issues and everything between. 

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