The Truth About Mixes And Selective Feeding

True or False: The mix only makes up a small portion of my pets’ diet.  If I provide other healthy foods such as hay there won’t be any negative consequences.

FALSE: Nutritional and behavioral impacts of muesli and foraging mixes have both short and long-term health impacts.  These impacts include:

Mix-Based Diets Can Exacerbate Already Instinctual Selective Feeding Behaviors

• Feeding mixes is dangerous because animals can be stimulated to become even more selective in their feeding as they start to prefer the softer, more palatable but less nutritious pieces of the mix and refuse foods that provide critical dental wear and fiber, such as hay.⁶

Decreased Hay and Water Consumption

• Animals fed a mix consumed less hay and drank less water compared to those fed a uniform pellet.5 These two outcomes have huge implications as chronic, low-grade dehydration can be tied to several negative health outcomes including kidney function and anemia.²¹

Greater Potential for Gastrointestinal Stasis and Bladder Sludge

• Hay and fiber intake, as well as hydration, are also factors that impact two of the most common health issues in small herbivores, GI stasis, and bladder sludge. It has been shown that increased water intake is favorable in the mitigation of urolithiasis (bladder stone), as is greater hay consumption.^22,23

True or False: I can just train my pet not to selectively feed and eat all of the mix for more balanced nutrition.

FALSE: You may have noticed many of the issues with muesli, foraging, and seed-based mixes revolve around selective feeding, which has been recognized in exotic companion mammals for decades. This is not an issue that can be conquered with training because it is truly a hard-wired survival mechanism that has evolved in these animals for hundreds of years.

Concentrate Selecting (i.e. Selective Feeding) in the Wild
Wild small mammals (both herbivorous and omnivorous) rely on selective feeding to survive, so it is deeply engrained in their genetics. Small mammals are prey in the wild and have a relatively low storage capacity for food in the stomach to make it easier to escape predators (think about trying to run after a big meal). So, to meet their nutrition and energy requirements, they select the most nutritionally dense foods.8-10 In this hunt for food, wild rabbits may spend up to 11 hours per day feeding and foraging while covering more than 5 acres of land in their home range.^11-13

What Happens When “Wild” Becomes “Child”?
For wild animals, selective feeding is a means to survive but your pet sitting on the couch next to you is a different story. There’s no more food scarcity or daunting, predator-filled landscape to traverse for them in your home!  Unfortunately, the hardwired drive to selectively feed is still very much present and will lead them to select high starch, high sugar, high-calorie food items when given the chance.

Rabbits and guinea pigs will even select for the less fibrous portions of loose hay, and rabbits are even more selective than guinea pigs.¹⁴

In addition to selecting energy-dense foods, these species are also highly motivated by the palatability of different foods rather than their nutritive value.¹⁰

All of this to say, there is no way to prevent your small pet from selectively feeding, given the opportunity.  Instead, it is up to you to provide them with the best quality nutrition possible by removing the opportunity to selectively feed.

References

Harcourt-Brown, F.M. 1996. Calcium deficiency, diet and dental disease in pet rabbits. Veterinary Record 139.23: 567-571.
Lebas, F., P. Coudert, H. De Rochambeau, and R.G. Thébault. 1997. The Rabbit – Husbandry, Health and Production (2d edition) FAO publ., Rome, pg. 223.
Mullan, S.M., and D.C.J. Main. 2006. Survey of the husbandry, health and welfare of 102 pet rabbits. Veterinary Record 159.4: 103-109.
Meredith, A.L., J.L. Prebble, and D.J. Shaw. 2015. Impact of diet on incisor growth and attrition and the development of dental disease in pet rabbits. Journal of Small Animal Practice 56.6: 377-382.
Prebble, J.L., and A.L. Meredith. 2014. Food and water intake and selective feeding in rabbits on four feeding regimes. Journal of Animal Physiology and Animal Nutrition 98.5: 991-1000.
Jekl, V., and S. Redrobe. 2013. Rabbit dental disease and calcium metabolism–the science behind divided opinions. Journal of Small Animal Practice 54.9: 481-490.
Prebble, J.L., F.M. Langford, D.J. Shaw, and A.L. Meredith. 2015. The effect of four different feeding regimes on rabbit behaviour. Applied Animal Behaviour Science 169: 86-92.
Miller, G.R. 1968. Evidence for selective feeding on fertilized plots by red grouse, hares, and rabbits. The Journal of Wildlife Management: 849-853.
Somers, N., B. D’Haese, B. Bossuyt, L. Lens, and M. Hoffmann. 2008. Food quality affects diet preference of rabbits: experimental evidence. Belgian Journal of Zoology 138.2: 170-176.
Gidenne, T., F. Lebas, and L. Fortun-Lamothe. 2010. Feeding behaviour of rabbits. In: Nutrition of the Rabbit, Eds: de Blas, C. and Wiseman, J. CAB International. Pgs: 254-274.
Mykytowycz, R., 1958. Continuous observations of the activity of the wild rabbit, Oryctolagus cuniculus (L.), during 24-hour periods. C.S.I.R.O. Wildl. Res.
Myers, K., and W.E. Poole. 1961. A study of the biology of the wild rabbit, Oryctolagus cuniculus (L.), in confined populations II. The effects of season and population increase on behaviour. C.S.I.R.O. Wildl. Res. 6, 1–41.
Gibb, J.A. 1993. Sociality, time and space in a sparse population of rabbits (Oryctolagus cuniculus). Journal of Zoology 229.4: 581-607.
Franz, R., M. Kreuzer, J. Hummel, J.M. Hatt and M. Clauss. 2011. Intake, selection, digesta retention, digestion and gut fill of two coprophageous species, rabbits (Oryctolagus cuniculus) and guinea pigs (Cavia porcellus), on a hay‐only diet. Journal of Animal Physiology and Animal Nutrition 95.5: 564-570.
National Research Council (NRC). 1977. Nutrient Requirements of Rabbits: Second Revised Edition. Washington, DC: The National Academies Press.
European Pet Food Industry Federation (FEDIAF), 2013: Nutritional Guidelines for Feeding Pet Rabbits. FEDIAF, Brussels (Belgium).
Lowe, J.A. 2010. Pet Rabbit Feeding and Nutrition. In C. de Blas and J. Wiseman (eds.) Nutrition of the Rabbit 2nd ed.). CAB International. Pp. 294-313.
Gidenne, T. 2003. Fibres in rabbit feeding for digestive troubles prevention: respective role of low-digested and digestible fibre. Livestock Production Science 81.2-3: 105-117.
Rees Davies, R. and J.A.E. Rees Davies. 2003. Rabbit gastrointestinal physiology. Veterinary Clinics: Exotic Animal Practice 6.1: 139-153.
DeCubellis, J, and J. Graham. 2013. Gastrointestinal disease in guinea pigs and rabbits. Veterinary Clinics: Exotic Animal Practice 16.2.: 421-435.
Melillo, A. 2007. Rabbit clinical pathology. Journal of Exotic Pet Medicine 16.3: 135-145.
Clauss, M., B. Burger, A. Liesegang, F. Del Chicca, M. Kaufmann-Bart, B. Riond, M. Hassig, and J.M. Hatt. 2012. Influence of diet on calcium metabolism, tissue calcification and urinary sludge in rabbits (Oryctolagus cuniculus). Journal of Animal Physiology and Animal Nutrition 96.5: 798-807.
Tschudin, A., M. Clauss, D. Codron, A. Liesegang, and J.M. Hatt. 2011. Water intake in domestic rabbits (Oryctolagus cuniculus) from open dishes and nipple drinkers under different water and feeding regimes. Journal of Animal Physiology and Animal Nutrition 95.4: 499-511.