Being able to identify excess weight gain or loss in body condition plays an important role in supporting your horse’s health and well-being. Regular monitoring is key to success. It helps you spot gradual changes, track progress, and decide whether further changes in diet and/or management might be needed.

In this article, we explore some of the practical monitoring tools you can add to your toolbox. (Editor’s note: Make sure to check out our article on body condition scoring.)

Weigh Bridges/Scales

A weigh bridge/scale is the most accurate method of measuring body weight in horses and ponies of all ages, breeds, and sizes. If you’re not lucky enough to have one at your barn, ask staff at your local veterinary center or equestrian center if they have one you can use.

It’s important that weigh bridges/scales are calibrated regularly to ensure accuracy.

Weight Tapes

Most owners don’t have the luxury of regular (if any) access to a weigh bridge/scale. Therefore, a weight tape is a more practical option. A weight tape might under- or overestimate the horse/pony’s actual weight. But, if used correctly, it can be a useful way of monitoring gradual changes. To use:

  • Make sure your horse is standing as squarely as possible on a firm, level surface.
  • Place the weight tape over the horse’s back at the base of the withers.
  • Bring the tape underneath the girth area just behind the foreleg and elbow.
  • Check that your weight tape is correctly positioned. It is likely it will be on a slight angled line. Incorrect positioning will affect the accuracy, so always check the manufacturer’s instructions.
  • Always use the same weight tape to help improve accuracy when comparing measurements over time.
  • Try to monitor your horse’s weight weekly, ideally at the same time of day as changes in gut fill can affect the result—this why most of us prefer to stand on the scales first thing in the morning!
  • Remember that weight tapes are not accurate for pregnant mares, foals or youngstock (especially those under 6 months of age).

Belly Girth

Measured around the widest point of the trunk (belly) with the tape positioned in a straight line, belly-girth can be a very sensitive indicator of generalized fat loss in response to changes in diet. This perhaps makes it one of the most useful weight monitoring tools in overweight horses and ponies. Monitoring heart girth can also be very useful.

belly girth measurement
Copyright Spillers

Heart Girth

Heart girth is measured as the horse/pony breathes out by passing a tape measure immediately behind the base of the withers and the elbows (see BCI image for positioning).

Tips: Measure belly girth and/or heart girth weekly and record the measurements so you can monitor changes. It doesn’t matter whether you use centimeters or inches, as long as you are consistent. Remember some horses and ponies might be ticklish, so take care—especially if they’re not used to having their measurements taken!

Rump Width

Rump width is measured from the point of one hip to the point of the other over the rump. Watch for changes in this measurement.

rump width illustration
Copyright Spillers

The Body Condition Index (BCI)

The body condition index (BCI) is a method of assessing body fat, similar to the body mass index (BMI) used in humans. The original body condition index was developed in 2015, but thanks to new research, the improved version provides greater accuracy.

A mathematical equation using five body measurements—height, heart girth, belly girth, length, and neck circumference—is used to calculate the horse’s final body condition index score. Horses and ponies scoring 18-22 are likely to be overweight, whereas those scoring more than 22 are likely to be obese.

body condition index illustration
Copyright Spillers

(Author’s note: While calculating your horse’s body condition index might sound complicated, this easy-to-use online tool does all the math for you. All you do is enter your horse/pony’s measurements into the calculator.)

Body Condition Index (BCI) vs. Body Condition Score (BCS)

Body condition scoring is a practical method of assessing body fat by eye and by touch using a numerical grading system—most commonly a 0-5 or 1-9 scale. While body condition scoring certainly has its merits, including the fact that it can be used to assess horses/ponies in ideal, lean, and poor condition, there is a degree of subjectivity involved.

Body condition score can also be slow to change initially in very overweight/obese horses and ponies on a restricted diet, despite them losing internal fat, so it might not be the ideal way of monitoring early progress. It can also sometimes feel a little daunting or confusing to carry out, even for experienced owners.

The body condition index is more objective because it uses measurements. If you’re unfamiliar with or feel less confident about body conditioning scoring, the new BCI might be just thing for you!

Is the BCI Suitable for All Horses and Ponies?

The BCI is designed for use in adult horses and ponies of various breeds and sizes. However, accuracy in Shetlands and miniatures varies. It has not yet been tested widely in large draft breeds.

Like all practical weight management tools, the BCI should be considered a guide regardless of breed. If you have any concerns, speak to a nutrition advisor or your vet. That said, it can be a very useful way of tracking weight loss and gain in individual horses and ponies.

The BCI is not suitable for mares in mid- to late gestation or horses and ponies with a potbelly. 

The Science Behind the New BCI

The new BCI was initially developed using 21 horses and ponies in moderate (ideal) and obese body condition. This involved assessing body condition score (BCS), measuring height, length, belly girth, heart girth, and estimating total body fat using the gold standard method of deuterium oxide dilution (a specialist clinical test).

Once developed, accuracy of the new BCI was tested using data from three separate studies involving a further 628 horses and ponies. Overall, the BCI was found to:

  • correlate well with total body fat percentage (measured using the gold standard method);
  • compare well to body condition score when body condition scoring was completed by experienced assessors; and
  • be more reliable than body condition scoring completed by inexperienced assessors.

The full research paper is published in the Equine Veterinary Journal and is free to access online.

  • As Product Manager for SPILLERS, Sarah Nelson is responsible for the technical management of all SPILLERS products, including recipe formulation.
    View all posts