Excessive bodyweight has become a major health issue in the equine industry. The objectives of the study, conducted at he University of Minnesota, were to determine if the addition of neck circumference and height improved existing bodyweight estimation equations; develop an equation for estimation of ideal bodyweight; and develop a method for assessing the likelihood of being overweight in adult equines.
In 2011, 629 adult horses and ponies were measured and weighed at two horse shows in Minnesota (WSCA Champ Show and State 4-H Horse Show). Personnel assessed body condition score (BCS) on a scale of 1 to 9, measured wither height, body length from the point of shoulder to the point of the buttock, neck and girth circumference, and bodyweight using a livestock scale. Individuals were grouped into breed types and equations for estimated and ideal bodyweight were developed. For estimated body weight, the model was fit using all individual equines. For ideal bodyweight, the model was fit using only individuals with BCS of 5. Breed type, height and body length were also considered as these measurements are not affected by fat deposits. Finally, a bodyweight score to assess the likelihood of being overweight was developed and standardized using horses with a BCS of 5.
Breed types included Arabian, stock and pony. Mean BCS was 5.6. Bodyweight (lbs) was estimated by taking girth (in)1.486 x length (in)0.554 x height (in)0.599 x neck (in)0.173/119 (Arabians), 119 (ponies) or 114 (stock horses). Ideal body weight (lbs) was estimated by taking length (in) x 15.65 + height (in) x 23.47 – 1,344 (Arabians), 1,269 (ponies) or 1,333 (stock horses).
Equines with a BCS of ≥ 7 had a greater likelihood of being overweight and the model suggested cutoffs at the 48th and 83rd percentiles for underweight and overweight horses, respectively. In conclusion, body measurements were successfully used to develop equine bodyweight-related equations.
To encourage use of the equations, the research team developed a mobile app for Apple and Android operating systems. Users enter the body measurements and the app calculates estimated and ideal bodyweight and a bodyweight score.
Information on the “Healthy Horse” app can be found here. For more information on this research, click here.
Summarized by Krishona Martinson, PhD, University of Minnesota