Body condition scoring (BCS) is a useful tool for assessment of a patient’s general health status and evaluation of a patient’s food supply. The BCS system described below is based on scores between 1 and 5, with 1 being emaciated and 5 being obese for the “generic” bird (Fig 1).
Currently there is no universally agreed upon BCS system for the avian patient due to the high degree of species variability. Individual variability is also seen within a species, and can be due to the level of activity (i.e. wing trimmed versus active flier), “life style” (i.e. free-ranging versus captive), and the season of the year (particularly in migratory species).
Assessing body condition score in adult birds
To evaluate body condition:
- Palpate the breast muscles immediately alongside the ventral ridge of the keel bone or carina. Note the convexity or concavity of the pectoral muscle mass contour (Fig 2)
- Note the degree of prominence of the keel (Fig 2)
- Look for subcutaneous fat deposits over the sternum, sides, coelom, flanks, thighs, and neck. Wetting feathers with alcohol can improve visualization of yellow subcutaneous fat deposits (Fig 3)
Body condition scores were originally created to try to quantify the degree of pectoral muscle mass lost in ill birds. These systems can be less accurate in identifying or quantifying obesity, however as body condition increases body weight and fat stores increase.
- The thin bird (BCS 1 to 2) is bony with little muscle over the sternum (Fig 1). The keel bone will display a prominent “V” shape.
- The bird in ideal body condition (BCS 3) has a good overall appearance, with a pectoral muscle contour appropriate for the species.
- An overweight to obese bird with a BCS of 4 to 5 has a plump breast with variable amounts of subcutaneous fat and coelomic distension. The contour of the chest displays a broad “U” shape.
Overweight birds often deposit fat within subcutaneous tissues, particularly over the coelom and lateral flanks. Subcutaneous fat depots in the inguinal space can create a broad-based stance, while fat deposits underneath the beak can create a “double chin”. Fat deposits along either side of the keel can also create a part in feathers overlying the sternum, although the presence of “cleavage” does not necessarily mean the bird is overweight (Fig. 4). Morbidly obese patients, particularly budgerigar budgerigars and Amazon parrots, can also possess lipomas.
Body condition score in juvenile birds
In pediatric patients, body condition cannot be assessed by palpation of the pectoral muscle mass, which is small, soft, and flabby. Instead, evaluate the amount of soft tissue and fat over bony areas like the pelvis and toes.