Star Milling

Feed Your Horse By Weight, Not Volume

Historically most horse owners have developed or learned the feeding practice of feeding scoops of grain and flakes of hay. With this practice we are assuming that all feedstuffs that appear similar weigh the same. This is not true. Feeding by volume will usually lead to overfeeding. If you are overfeeding, not only does your horse gain weight but you are also spending more money for the weight gain and more money to maintain that extra body weight.

Forages, mixes, and additives must be fed by body weight. The daily nutrient requirements are based on body weight and production level, such as growth, pregnancy, lactation and activity. If you are feeding hay (or pasture) and a balance commercial feed mix to maintain your horse’s body condition score, then you are on the right path. Even with the number of commercial feeds available today, there are still horse owners who mix their own ingredients to feed their horses. Simple examples of differences in measuring feed by weight vs volume are provided for comparison.

Measuring Grain/Mixes by Weight or Volume

The practice that a small coffee can of any feed weighs one pound most likely originated from the first coffee cans having one pound of coffee. That original 16 oz can filled with oats also weighed 1 pound, thus the “coffee can filled with any feed must weigh a pound.” This is wrong!

Feeds have different densities, translating to different weight per volume. Click here to see the weights of various horse feeds and hay pellets.

Table 1 provides the weight of one quart of several feedstuffs, the amount of energy per pound, and the total digestible energy for one quart of the respective feeds. Note that one quart of oats has twice the weight as one quart of wheat bran (1.0 lb vs 0.5 lbs). If you look at the far right hand column you will observe that oats provides almost twice the energy than an equal volume of wheat bran (1.3 vs 0.7 Mcal DE). Now compare the two feed pellets, A & B. One quart of Pellet A has 23% more weight (1.6 vs 1.3 lbs) and 50% more energy (2.4 vs 1.6 Mcal DE) than Pellet B. The message from this table comparison is that equal volumes are not equal weights or equal amounts of energy.

Table 1. Weight vs Volume

Feedstuff Weight (lbs) of 1 quart Energy in 1 pound (Mcal DE) Total Energy is 1 Quart (Mcal DE)
Oats 1.0 1.32 1.3
Wheat bran 0.5 1.33 0.7
Corn 1.7 1.54 2.6
Pellet A 1.6 1.52 2.4
Pellet B 1.3 1.25 1.6

DE = Digestible Energy
Mcal = Megacalorie, a unit of energy; 1 Mcal = 1000 kcal

Comparing Hay: Flake vs Weight

The comparison of volume and weight principle also applies to feeding hay. The feeding value of hay will vary with square bales for weight, hay type, number of flakes, hay maturity and cutting. For example, a bale of grass hay on the east coast may weigh 45-60 lbs compared to 90-130 lbs on the west coast. If an east coast 50 lb bale of grass hay averaged 13 flakes, then each flake would weigh 3.8 lb per flake. If compared to a 110 pound bale of west coast grass hay averaging 16 flakes per bale, then each flake would weigh 6.9 lb. The west coat flake is about 80% heavier than the east coast flake.

From a more practical approach, let’s compare a 90 lb bale of Bermuda grass hay to a 115 lb bale. Each bale has 16 flakes. The difference is 5.6 vs 7.2 lbs. To ensure that your horses are receiving the appropriate amount of hay, check the bale weight and average number of flakes per bale for each hay load. Feeding by scoops or flakes will work as long as know the weight for the volume of feed that is being fed.