OBJECTIVE To evaluate use of an ultrasonographically and radiographically determined value, the vertebral epaxial muscle score (VEMS), for assessing muscle mass in cats. ANIMALS 30 healthy neutered cats of various body weights and between 1 and 6 years of age. PROCEDURES Mean epaxial muscle height was calculated from 3 transverse ultrasonographic images obtained at the level of T13. Length of T4 was measured on thoracic radiographs, and the VEMS (ratio of epaxial muscle height to T4 length) was calculated and compared with body weight. Ratios of epaxial muscle height to various anatomic measurements also were compared with body weight as potential alternatives to use of T4 length. RESULTS 1 cat was excluded because of a heart murmur. For the remaining 29 cats, mean ± SD body weight was 5.05 ± 1.40 kg. Mean epaxial muscle height was 1.27 ± 0.13 cm, which was significantly correlated (r = 0.65) with body weight. The VEMS and value for epaxial muscle height/(0.1 × forelimb circumference) were not significantly correlated (r = −0.18 and −0.06, respectively) with body weight, which is important for measures used for animals of various sizes. CONCLUSIONS AND CLINICAL RELEVANCE The VEMS and value for epaxial muscle height/(0.1 × forelimb circumference) can both be used to normalize muscle size among cats of various body weights. Studies are warranted to determine whether these values can be used to accurately assess muscle mass in cats with various adiposity and in those with muscle loss.

The body condition score (BCS) is insufficient in determining the amount of body fat in horses, thus defining obesity. Measurement of the subcutaneous fat thickness (SFT) by ultrasonography should be considered as an appropriate method in the definition of fat distribution at different body locations in horses. Therefore, this study aimed to 1) characterize the SFT in three different anatomical locations (i.e. neck, lumbar region, and gluteal region); 2) evaluate the relationship between BCS and SFT; 3) determine the influence of gender, weight, age, and gait on BCS and SFT measurements, and 4) explore the agreement between the morphometric measurements [i.e. body mass index (BMI), girth circumference: height at withers ratio (GC: HW), neck circumference: height at withers ratio (NC: HW)], and BCS and SFT in a population of Colombian Paso Horses (CPHs). The Henneke’s body condition scoring was applied to 69 adult CPHs, selected using a convenience sampling. Additionally, BMI, GC: HW, and NC: HW were calculated. Body fat percentage (BF%) was calculated by ultrasound measurement of the SFT in the neck, lumbar region, and gluteal region. The BF% in the CPHs was 6.4 ± 1.1. The GC: HW, NC: HW, and BMI were not predictors of the BF% or BCS, and neither gender nor gait was decisive in the definition of fattening in the study animals, although age and weight were determining variables. According to our results, ultrasound is an adequate tool to calculate the BF% of the CPHs. However, it must be accompanied by Henneke’s BCS assessment.