How Does Your Horse Measure Up?

By Jessica R. Bussard

M.S. Candidate in Crop Science, Plant and Soil Sciences Department, University of Kentucky, Penn State University, Animal Science Alumnus

Knowing the body weight and condition of your horse is important in many aspects of horse care, whether it be designing nutritional feeding programs, administering medication, or just making sure you get the right size blanket.

The average horse owner’s options for estimating weight on-farm consist of weight tapes, formulas, or the good old “eyeball” method.  However, many of these options may yield inaccurate results.  The ideal situation, though unrealistic, would be to weigh the horse on a livestock scale. 

To find the most accurate approach researchers at Auburn University decided to test three commonly used methods.  Using a total of 145 adult horses of varying breeds and body types they determined actual weights on a portable livestock scale.  They then used three commonly used methods, a commercially available weight tape and two estimation formulas based on measurements, to estimate the horses’ weights. 

After data analysis was conducted the researchers found that though all three methods underestimated the actual body weights of the horses, there was one method in particular that yield a smaller degree of error versus the others. 

The estimation formula known as the point measurement yielded the most accurate estimates, only underestimating weights by approximately 17.25 kg or 38 lbs.  The point measurement formula is as follows:  (kg) = (heart girth2 x body length)/(11,880 cm3) with length defined as “measuring from the point of shoulder to the point of the buttock.”  The commercial weight tape was found to be the most inaccurate of the three, underestimating weight by nearly 65.81 kg or 145 lbs. 

The researchers noted that various weight tapes are available to horse owners, with each differing in the measurement systems used to estimate weight.  This variation results in slightly different results from one weight tape to the next.  In the end, no single method of weight estimation, other than actually using a scale, is perfect.  But when a scale isn’t available the point measurement formula appears to be the best choice.

Another option for evaluating a horse’s body condition is known as body condition scoring (BCS).  This method was developed by researchers at Texas A & M University as a way for nutritionists, veterinarians, and horse owners to evaluate nutritional status in horses by estimating the amount of fat on a horse’s body.  Body condition is scored on a scale of one to nine.  Ratings are based on palpation and visual assessment of fat deposits.

Ideal BCS for horses will vary depending on activity level and use but range between four and seven.  Horses in high energy sports such as racing would be desired to have a BCS of four.  While a pregnant or lactating mare would be expected to have a BCS around six or seven.  For most adult riding horses in light to moderate activity an ideal BCS is five.

With all of these methods, it is important to become familiar with them before implementation.  If unfamiliar with any of these methods of weight and body condition estimation, I suggest horse owners contact their veterinarian, equine nutritionist, or local extension agent.  These individuals will be able to give owners more information and assist them in estimating their horse’s weight and/or body condition.  With this information horse owners will be better equipped to make management decisions.

Jesse R. Bussard is a Pennsylvania cowgirl with a degree from Pennsylvania State University in animal science. Currently she is pursuing graduate studies in plant and soil science at the Uni­versity of Kentucky in Lexington, Ky. She is an active blogger and social media participant. Her personal blog is Pearl Snaps’ Ponder­ings (http://pearl-snapsponderings.wordpress.com/).