Body Condition Scoring the Rabbit

Introduction

Depending on breed and gender, body weight can vary widely among adult rabbits. Small breeds, like the Netherland dwarf, can weigh as little as 1 kg while large to giant breeds can exceed 5 to 7 kg. Many pet rabbits are mixed breeds that fall somewhere in the middle weighing between 2 to 5 kg (Fig 1).10,16

Most pet rabbits are medium-sized mammals.

Figure 1. Most pet rabbits are medium-sized and range from 2 to 5 kg. Image by Jody Nugent-Deal. Click image to enlarge.


Normal conformation can also vary widely among breeds. Dwarf rabbits tend to have small, stocky bodies while giant breeds display a high, curved top line over the rump referred to as a “mandolin shape” by fanciers. Some breeds, like the Belgian hare, have a relatively long, lean shape.15

 

 

Evaluating body condition

Body condition scoring is a technique used to assess body condition in many species. Although no official scoring system exists for rabbits 8, evaluation of rabbit body condition can be adapted from methods used in cats, dogs, and large animals (Fig 2).11,15 This subjective assessment technique relies upon palpation of fat and musculature over the ribs, bony prominences, and rump as well as evaluation of the dewlap.9-11

  • Palpate the ribs just behind the elbow. The ribs should ideally be covered by only a light layer of fat and are therefore easily palpable with light pressure.
  • Bony prominences, such as the hips, shoulder blades, and spine, should be easily palpable with moderate pressure.
  • The rump area should ideally appear flat, although normal conformation varies with breed. The rump also becomes increasingly round and then convex as body condition moves from “plump” to “obese”.
PFMA BCS large size

Figure 2. Rabbit body condition scoring chart by the Pet Food Manufacturer’s Association (PFMA). Posted with permission. Click image to enlarge.

 

Record the rabbit’s body weight on an accurate scale that changes in increments of 1 gram or less. Standard body weights do exist for show rabbit breeds, but determining there is a lack of standard data for mixed breed rabbits.10 The differences in husbandry for show versus pet rabbits also influences body weight.10

As body weight increases in the rabbit, excess subcutaneous fat tends to be deposited in the axillary and inguinal regions. It also becomes increasingly difficult to palpate the hips, ribs, and spine. Fat is also deposited within the dewlap. The dewlap is a large skin fold beneath the chin, usually only visible in female rabbits. The dewlap can become quite large in older breeding does (Fig 3). The dewlap can also increase greatly in size in overweight rabbits, however this large dewlap can persist after weight loss.9-11 Excessive abdominal fat can also make palpation of internal organs difficult.

Rabbit dewlap (arrow)

Figure 3. The dewlap, a large skin fold, over the throat (arrow) can become quite large in older breeding does. Image by Akira Ohgaki.

 

Additional non-invasive techniques used to evaluate body composition include dual-energy x-ray absorptiometry (DEXA) and the zoometric ratio, which has been described in medium-sized rabbits.1,2,14 The zoometric ratio (body weight divided by distal forelimb length) is analogous to body mass index in humans.14

 

 

Obesity in rabbits

Obesity is a common problem in pet rabbits.3,10 Energy-rich, low-fiber diets high in pellets and restriction of exercise are common underlying causes of weight gain.1,17 Old age and chronic conditions, like osteoarthritis, can also contribute to obesity.1,13 Signalment, such as large and giant breed, female gender, and/or neutering may also serve as risk factors for weight gain.1,3,5,15

Obesity can lead to significant morbidity and mortality in rabbits.1,13,15

  • Obesity raises the risk of complications associated with anesthesia and surgery.13 The mesometrium can serve as a major fat depot, making identification and ligation of blood vessels much more challenging during ovariohysterectomy.12 Overweight rabbits are also at increased risk for post-anesthetic complications such as gastrointestinal ileus.1,6,15
  • Overweight rabbits are at increased risk for pododermatitis or “sore hocks”.3,15 Pododermatitis is particularly common in rex rabbits due to the thin layer of fur present on the on plantar surf of their feet.
  • Overweight rabbits cannot groom normally, which can increase the risk of a scruffy or matted hair coat as well as cheyletiellosis, or myiasis.3,15
  • Fat can also collect within skin folds, particularly folds around the perineum, making grooming more difficult and leading to skin fold pyoderma.1 British giant and French lop breeds are particularly likely to develop skin fold pyoderma beneath the dewlap or around the perineum.16 Perineal skin fold fat depots can also promote misdirected urine flow, urine retention, and entrapment of urine in hair and skin which in turn can lead to bladder sludge, cystitis, and urine scald.1,17 The overweight rabbit may also be unable to ingest nutrient-rich cecotrophs.16 Therefore fecal staining can also develop.17 Impaired cecotrophy also increases the risk of nutritional deficiencies and intestinal dysbiosis in the overweight rabbit.1
  • Overweight does are at increased risk for pregnancy toxemia.13
  • Since rabbits possess a relatively light skeleton, excessive weight can increase the pressure applied to joints. When this weight-related stress on joints is paired with reduced activity, the development of osteoarthritis is promoted.1,15
  • Overweight rabbits are at risk for cardiovascular disease.1 Laboratory rabbits fed high-fat, high-cholesterol diets are prone to develop atherosclerosis.1,19
  • Finally, hepatic lipidosis can also develop rapidly if an obese rabbit becomes anorectic.3,13,15

 

 

Client education

When owners and veterinary staff evaluate a pet’s body condition, the two groups can come away with very different impressions. In a pet obesity survey sponsored by the Pet Food Manufacturer’s Association 9, 80% of dog, cat, and rabbit owners believed that their pet was the perfect weight, although no more than one-third were able to correctly identify a photograph showing an animal with an ideal body condition.7,9 Fortunately, there was good agreement between veterinary and owner assessment when owners were taught the PFMA body condition scoring scale (Fig 2).15

Veterinary professionals should use the physical examination as an opportunity to teach owners how to evaluate their pet’s body condition score. Owners can then be encouraged to monitor their pet’s body condition on a monthly basis, and if the rabbit is overweight, regular (every 2-4 week) weigh-ins on a clinic scale may also be indicated. Giving the owner something concrete to do can be much more successful for weight control when compared to verbal instructions alone.18

Additional measures to prevent and/or control obesity in pet rabbits include offering an appropriate diet that includes high-quality hay ad libitum, a small quantity of high-fiber pellets or extruded nuggets, and healthy treats, like herbs and greens.1,10 The rabbit should also be provided adequate space and opportunities for exercise and enrichment.1,4 The Rabbit Welfare Association and Fund recommends a minimum of 3 m x 2 m with a height of at least 1 m for a pair of average-sized rabbits.12 Enrichment should be provided that allows the rabbit to express natural behaviors, such as hideaways, tunnels, as well as foraging and digging opportunities.1 Any changes in diet or activity level should be made very gradually.1

 

 

References

References

1.  Adji AV, Pederson AØ, Agyekum AK. Obesity in pet rabbits (Oryctolagus cuniculus): A narrative review. J Exotic Pet Med. 2022;41:30-37. doi: 10.1053/j.jepm.2022.02.003.

2.  Alexandersen P, Hassager C, Christiansen C. Influence of female and male sex steroids on body composition in the rabbit model. Climacteric. 2001;4(3):219-27. PMID: 11588946.

3.  Courcier EA, Mellor DJ, Pendlebury E, Evans C, Yam PS. Preliminary investigation to establish prevalence and risk factors for being overweight in pet rabbits in Great Britain. Vet Rec. 2012 ;171(8):197. doi: 10.1136/vr.100792. Epub 2012 Jul 10. PMID: 22781344.

4.  Dixon LM, Hardiman JR, Cooper JJ. The effects of spatial restriction on the behavior of rabbits (Oryctolagus cuniculus). Journal of Veterinary Behavior. 2019;5(6):302-308.

5.  Georgiev IP, Georgieva TM, Ivanov V, et al. Effects of castration-induced visceral obesity and antioxidant treatment on lipid profile and insulin sensitivity in New Zealand white rabbits. Res Vet Sci. 2011;90(2):196-204. doi: 10.1016/j.rvsc.2010.05.023. Epub 2010 Jun 12. PMID: 20542306.

6.  Lee HW, Machin H, Adami C. Peri-anaesthetic mortality and nonfatal gastrointestinal complications in pet rabbits: a retrospective study on 210 cases. Vet Anaesth Analg. 2018;45(4):520-528. doi: 10.1016/j.vaa.2018.01.010. Epub 2018 Feb 27. PMID: 29759902.

7.  Mayer J, Brown S, Mitchell MA. Survey to investigate owners׳ perceptions and experiences of pet rabbit husbandry and health. J Exotic Pet Med. 2017;26(2):123-131. doi:1053/j.jepm.2017.01.021.

8.  MSU. Feeding your adult rabbit. Michigan State University Veterinary Teaching Hospital web site. Available at http://cvm.msu.edu/hospital/services/nutrition-support-service-1/client-education/feeding-your-adult-rabbit-1. Accessed on March 30, 2013.

9.  PFMA. Pet obesity campaign. Pet Food Manufacturer’s Association web site. 2009. Available at http://www.pfma.org.uk/pet-obesity-campaign/. Accessed on March 30, 2013.

An updated version can be found at https://www.pfma.org.uk/rabbit-size-o-meter.

10. Prebble JL, Shaw DJ, Meredith AL. Bodyweight and body condition score in rabbits on four different feeding regimes. J Small Anim Pract. 2015;56(3):207-12. doi: 10.1111/jsap.12301.

11.  Reusch B. Why do I need to body condition score my rabbit? Rabbit Welfare Association & Fund Web site. Spring 2010. Available at rabbitwelfare.co.uk/pdfs/ROSpring10-Bodyconditionscore.pdf. Accessed on March 30, 2013.

12.  RWFA. Rabbits need SPACE. Rabbit Welfare Association and Fund web site. Available at rabbitwelfare.co.uk/rabbit-care-advice/rabbit-housing/space-recommendations/. Accessed August 21, 2022.

13. Shrubsole-Cockwill A. Obesity A. In: Mayer J, Donnelly TM (eds). Clinical Veterinary Advisor: Birds and Exotic Pets. St. Louis, MO: Elsevier Saunders: Publisher; 2013. Pp. 401-402.

14.  Sweet H, Pearson AJ, Watson PJ, German AJ. A novel zoometric index for assessing body composition in adult rabbits. Vet Rec. 2013;173(15):369. doi: 10.1136/vr.101771. Epub 2013 Sep 27. PMID: 24078228.

15.  Thompson JL, Koh P, Meredith AL, Brown H. Preliminary investigations into the use of the five-point body condition scale (Size-O-Meter) and its use in pet owner education. J Exotic Pet Med. 2019;31:95-99. doi:  10.1053/j.jepm.2019.07.016.

16.  Vella D, Donnelly TM. Rabbits: Basic anatomy, physiology, and husbandry. In: Quesenberry KE, Carpenter JW (eds). Ferrets, Rabbits, and Rodents: Clinical Medicine and Surgery, 3rd ed. St. Louis: Elsevier Saunders; 2012:

17.  Vennen KM, Mitchell MA. Rabbits. In: Mitchell M, Tully TN (eds). Manual of Exotic Pet Practice. St. Louis, MO: Saunders Elsevier; 2009:  375, 390.

18.  White GA, Hobson-West P, Cobb K, et al. Canine obesity: is there a difference between veterinarian and owner perception? J Small Anim Pract. 2011;52(12):622-626. doi: 10.1111/j.1748-5827.2011.01138.x.

19.  Zheng H, Zhang C, Yang W, et al. Fat and cholesterol diet induced lipid metabolic disorders and insulin resistance in rabbit. Exp Clin Endocrinol Diabetes. 2009;117(8):400-405. doi: 10.1055/s-0028-1102918. Epub 2009 Mar 19. PMID: 19301228.

To cite this page:

Pollock C. Body condition scoring the rabbit. August 25, 2022. LafeberVet web site. Available at https://lafeber.com/vet/body-condition-scoring-the-rabbit/