Relationships Between Measurements of Body Fat in Thoroughbred Horses

Impacts of Adiposity on Exercise Performance in Horses

There is ample research describing the increased risk of health concerns associated with equine obesity, including insulin dysregulation and laminitis. For athletes, the negative effect of weight carriage is well documented in racing thoroughbreds (i.e., handicapping with weight) and rider weight has been shown to impact the workload of ridden horses and to some degree their gait and movement. In many groups of competitive and athletic horses and ponies, obesity is still relatively common. Therefore, these animals not only are at risk of metabolic disease, but also must perform at a higher workload due to the weight of their adipose tissue. Excess body weight has been documented to affect gait quality, cause heat stress and is expected to hasten the incidence of arthritis development. Meanwhile, many equine event judges appear to favor the look of adiposity in competitive animals. This potentially rewards horses and ponies that are at higher risk of disease and reinforces the owner's decisions to keep their animals fat. This is a welfare concern for these animals and is of grave concern for the equine industry.

Development and Evaluation of a Muscle Atrophy Scoring System (MASS) for Horses

Loss of skeletal muscle mass likely compromises performance and welfare in horses and thus routine monitoring would be valuable. Currently available methods to assess muscle mass require expert knowledge and are often expensive. To provide a simple method, a muscle atrophy scoring system (MASS) was created and tested by three evaluators (raters) in 38 horses of varying age, breed, and health status. Inter-rater agreement on atrophy scores was in the good-to-excellent range for ratings of the neck (ICC = 0.62), back (ICC = 0.62) and hind (ICC = 0.76) regions but was poor for the abdominal region (ICC = 0.29). Due to this low agreement, the abdominal region was excluded from further analysis. Associations between muscle atrophy scores and age, pituitary pars intermedia dysfunction (PPID) status, and body composition indicators, including weight and estimated fat-free mass (FFM), were examined. Weight was inversely associated with neck, back and hind muscle atrophy scores (β = -0.008, β = -0.008, β = -0.009, respectively; all P <0.001), but estimated FFM was not associated with muscle atrophy scores at any region (P >0.05). Age was positively related to neck (β = 0.030, P <0.01), back (β = 0.037, P <0.001) and hind (β = 0.040, P <0.001) muscle atrophy scores. PPID-positive horses (n = 4) had higher muscle atrophy scores than PPID-negative horses (n = 23), even after adjusting for age (P <0.05). This data suggests that neck, back and hind region evaluations by individual raters likely have acceptable reliability. In addition, these findings support further evaluation of the potential benefits of the MASS to identify and monitor muscle atrophy in horses.

Nutritional Considerations When Dealing with an Obese Adult Equine

Equine obesity is common, reducing quality of life and requiring dietary energy restriction. Equine obesity is identified using subjective body condition scoring. Considerations are given for life stage and health status when managing obese equines. Every effort should be made to maximize feeding duration, and minimize time spent without feed while meeting all essential nutrient requirements. Limiting total daily dry matter intake to 2% of current bodyweight per day of a low caloric, forage-based diet may result in adequate body weight loss. Weight loss and weight management plans should be monitored for success and potential gastrointestinal, metabolic, and/or behavioral complications.

Clinical Factors Associated With Survival Outcomes in Starved Equids: A Retrospective Case Series

Each year in the United States, unwanted horses may become neglected, starved, or abandoned. Recovery therapies include refeeding and veterinary care, often requiring substantial time and financial investments. To better understand the likelihood for starved horses to successfully survive the first 100 days after initial evaluation, a retrospective case series was performed using hospital records of starved horses at the University of Tennessee College of Veterinary Medicine. A body condition score (BCS) of 3 or less and a malnourished diagnosis were utilized to select case records from an 11-year period (n = 82). Animal descriptors, vital signs, complete blood count data, blood chemistry panels, parasite load, and refeeding diet information were analyzed as available within the case record. Mixed model analyses of variance (PROC GLIMMIX, SAS 9.4) were utilized to test if response variables differed in horses that lived or died. Generalized linear mixed models were used to test factors associated with survival probability 100 days postinitial hospitalization. Body temperature (P = .05) and BCS (P = .0002) were significantly lower in horses that died compared with horses that survived. In addition, white blood cells were increased in horses that died (11.6 ± 1.3 cells/μL) compared with horses that survived (8.6 ± 0.5 cells/μL; P = .03). The initial BCS was associated with probability for survival, where survival likelihood increased 14.6 times for each 1 whole unit increase in the BCS. These results indicate the relevance of using the BCS as a predictor for future survival and as a measure for clinical decision-making.