How do you Weigh a Horse?

Awhile back I wrote a post that stated you should feed your horse a minimum of 1.5% of it's body weight in forage. It's also useful to know how much your horse weighs when calculating grain rations and dosages of de-wormers and medications.

Under estimating the weight of your horse can cause problems with medications because the doses need to be carefully calibrated. According to my nutritionist it's common for owners -- and even veterinarians -- to underestimate a horse's weight by 10%, which would be at least 100 pounds for some horses. So, how do you weigh your horse?

The most accurate way to weigh a horse is on a livestock scale, but not many of us have access to one. A nutritionist that I used a truck weigh station: he drove his truck and trailer there once with a horse in it and once empty. I have also seen an ad for a company, Rhode Island Horse Weighing , that brings the scale to your barn!

For most of us though, using a weight tape is probably the simplest solution. It's not the most accurate, but if you measure your horse consistently you can at least see trends. Make sure your horse is standing square then place the tape behind your horse's withers and bring it down around his body in the girth groove, right behind the elbow and foreleg.

Weight tapes are available at tack stores and are often given away by feed companies. I generally have a few kicking around my tack room even though I'm not sure where they came from.

For the mathamatically inclined, there's a method that's more accurate than the weight tape but requires more calculations.

First, measure the heart girth using a standard measuring tape. You measure in the same place as when using the weight girth. Next, measure the length of your horse's body from the point of the shoulder to the point of the hip. Your tape measure should run at an angle as shown by the yellow line in the image.

With these measurements, you perform the following calculation:

(((heart-girth x heart-girth) x body-length) divided by 300) + 50 = weight.

For the mathamatically challenged, you can simply plug the numbers into this horse weight calculator.

Finally, there are two nomograms developed by C. L. Carroll and P. J. Huntington.

Method One
This nomogram for estimating body weight uses body condition score and height at the withers. The more accurately height and condition score are established, the better the weight assessment will be. Ensure that the horse is standing squarely on level ground, is relaxed, and with the head in the normal position before measuring its height.

Method Two
This nomogram for estimating body weight from girth and length measurements. This method is slightly more accurate and uses the measurements described above.