Diet
Reassuringly, Harrup and Rooney [ 49 ] and Norman and Wills [ 50 ] found that most owners provided hay either ad libitum( Figure 3) or often. High-fibre foliage is required constantly by the guinea pig ' s dentition and digestive system to prevent dental disease, such as malocclusion or distorted growth, and ileus [ 16 ]. However, as frequency is unknown and‘ staple food’ was identified as pellets by Norman and Wills [ 50 ], selective feeding and subsequent malnutrition are possible, as guinea pigs frequently choose pellets over hay, even when pellets are nutritionally incomplete [ 64 ].
Hay is not mentioned by Witkowska et al. [ 51 ], who also found pellets to be the main feed. It is unclear whether hay was omitted because the owners did not provide it or they were not asked about it. Lower reported provision of hay described in Cameron et al. [ 52 ] compared with Harrup and Rooney [ 49 ] may suggest under-feeding, but this theory is problematic as Cameron et al. [ 52 ] did not directly assess it.
The small sample used by Norman and Wills [ 50 ] may have contributed to their finding of no compelling relationship between dental disease and diet, but Müller et al. [ 64 ], who investigated the dental effects of abrasive diets and had similar results, found nutritional, hereditary and other issues to be more probable causes.
Correspondence between outdoor access and dental disease signs may mean natural grazing is better for dental health; further enquiry would be beneficial as it might propose significant changes to how owners house their guinea pigs. An example of outdoor access is illustrated in Figure 4.
Hypovitaminosis C has harmful consequences, namely anorexia, secondary bacterial infections, dental disease and sudden death [ 16 ]. These links are supported by Witkowska et al. [ 51 ], who found that two guinea pigs fed less vegetables had clinical signs of hypovitaminosis C, and Harrup and Rooney [ 49 ], who identified a negative correlation between regular feeding of green vegetables and dental disease.
Figure 3. A guinea pig with access to hay ad libitum.
In the findings, most owners purposely provided vitamin C. Interestingly, its supplementation is increasingly debated due to photodegradation, to
Figure 4. An example of outdoor access for guinea pigs.
26 Veterinary Nursing Journal