The following body condition scoring (BCS) scales have been obtained from a variety of sources. We have credited the authors where we can, and encourage you to submit newly developed or modified scales or corrections to attributions.
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About BCS Scales
Body condition scoring (BCS) is a subjective measurement of an animal’s muscle definition and superficial fatty tissue.
BCS for Zoo Animals
BCS has been used for many years in the livestock industry to evaluate and improve the productivity, health, reproduction and longevity of herds. BCS has become increasingly common in zoological settings for many of the same reasons. Our greatest challenge in zoos is to develop practical systems or scales for the diverse species with which we work. Some scales have been well-developed and validated, while others remain works in progress. The NAG encourages the careful and thoughtful development of new scales, the refinement of those that already exist, and the diligent attention to their implementation for the good of the animals in our care.
About BCS Scales
Body condition scoring scales are numerical, and they typically range from 1 (emaciated) to either 5 or 9 (obese). When using a 5-point scale, many people will assign half points (2.5 or 4.5 out of 5), which effectively turns the 5 point scale into a 9 point scale. Whenever possible, we recommend the use of a 9 point scale.
Implications of BCS Scores
Low BCS scores have been associated with lowered reproductive success, poor recovery from illness, and may be a sign of disease or age. High BCS scores have been associated with an increased risk of dystocia (difficulty giving birth), reproductive disorders, arthritis, diabetes, and other chronic conditions (Chan-McLeod et al. 1994; Burkholder 2000; Aeberhard et al. 2001; Busato et al. 2002; Berry et al. 2007; Boudreau 2012). Despite the known risks of being too far at either end of the BCS spectrum, a BCS score should be non-judgmental. You may be pleased that an animal recovering from a serious illness has moved from a 2 to a 3 (on a 9-pt scale), yet worry that a healthy animal has dropped from a 4 to a 3. You may be glad that an obese animal has dropped from an 8 to a 5, yet endeavor to raise an animal preparing for hibernation from a 5 to an 8 or 9 (which may be “normal,” physiologically, for the species in question). Keep in mind that just because it may be “normal” for a species to be over-conditioned at a specific time of year or life stage, this does not impact the BCS scale (a score of 8/9 remains 8/9, even if declared “appropriate” in terms of animal management; the scale does not “slide” to make that over-conditioned animal a 5/9). In addition, the scale is does not slide for growing, geriatric, or pregnant animals (regardless of stage of life, metabolic status, etc, the scale is designed to assess condition as objectively as possible).
Tips for Body Condition Scoring
- BCS is best learned and implemented through consistent practice. Often, it helps to have multiple staff involved at the start (animal managers, keepers, veterinarians, nutritionists, etc.) to make sure everyone is on the same page regarding terminology, anatomy, and the scoring system being used. In the end, however, it is often best to have a limited number of scorers so that consistency can be maintained. In addition, having someone who does not see the animals every day perform the scoring can be helpful.
- Scorers should be familiar with the anatomy of each species. If multiple scorers are utilized, they should be objectively evaluated for consistency with the same animals. It can be helpful to note the initials of the scorer when a BCS is performed and recorded.
- Although there are many different systems/scales (even for a single species), it is a good idea to pick one scoring system for each species and stick with it. This allows for increased familiarity and proficiency, over time.
- BCS is a particularly useful tool for animals that aren’t very tractable or for those who are unable to be weighed regularly. If body weights are available, BCS acts as a complementary assessment for management purposes. Ensure that the interval between BCS is reasonable and practical.
- For growing animals, body weights can be paired with appropriate growth curves to assess development. However, body weights in growing individuals often vary, even within species, and may not be the best assessment of growth. In these cases, BCS can be used not only to assess appropriate growth, but also to establish target weights for individuals.
Developing BCS Scales
If your species of interest does not have a scale established, please consider developing one. If you do, look at those that have already been thoughtfully developed.
Ideal BCS scales are easy to use, distinguish biologically relevant changes in status, provide enough description that multiple observers will obtain similar results, and, ideally, have been validated through other means (ultrasound, TOBEC, necropsy). Photographs and drawings should clearly show points of interest and be coupled with clear written descriptions. The NAG encourages you to share your systems by presenting a poster or presentation at our conference, or publishing in another format that can be accessed by the zoo community.
If you know of additional published resources for this page, we encourage you to submit them for potential inclusion: