88 Chapter 6effects of reduced appetite, vomiting and diarrhoea. Stella et al. (2011) found ‘sickness
behaviours’, most notably vomiting or regurgitation of food, bile or hair (hairballs),
diarrhoea or constipation, to be a consequence of cats subjected to periods of stress.
Reduced appetite and water intake, plus a reduction in the frequency of elimina-
tion leading to constipation, is a well-known and common response by cats to periods
of stress associated with hospitalization, cattery visits, re-homing, etc. If food intake
is severely reduced this can even result in the potentially fatal condition of hepatic
lipidosis.
A reduction in upper gastrointestinal motility caused by chronic stress might also
explain why some cats vomit or regurgitate hairballs on a regular basis (Sparkes
et al., 2016).
Obesity
Raised glucocorticoid levels have been shown to increase appetite in humans
(Tataranni et al., 1996) and overeating is a well-recorded reaction to chronic stress in
both humans and animals (McMillan, 2013). Obesity in cats may therefore also be
linked to chronic environmental stress. This might explain why standard weight loss
programmes for cats can sometimes be ineffective if underlying causes of stress are
not also identified and addressed (German and Heath, 2016).
Enforced diets that reduce the amount of food offered can also increase stress,
not only because of hunger and the reduction of food available, but in multi-cat
households reduced resource availability can be a common cause of tension and
conflict.
Perceived competition with other cats can also increase the amount of food that
a cat may eat at one time and the rate of food intake, causing the cat to eat much
faster than it would do normally. This may also contribute to overeating and obesity
because the cat might be more likely to demand food earlier than it would do if eating
little and often. However, another effect of eating too much too fast can be vomiting
or regurgitation of food soon after eating, which if happening frequently can result in
weight loss and poor condition.
The endocrine system
Diabetes mellitus
Diabetes mellitus is a metabolic condition in which the body is unable to utilize the
energy in food, leading to high blood-sugar levels and potentially serious health
complications.
The body’s blood-sugar level is regulated by the hormone insulin, which enables
the cells to utilize sugar (glucose) as energy and helps the liver to store excess glucose,
releasing it as required.
There are two types of diabetes mellitus:
● Type 1: the inability to produce sufficient insulin.
● Type 2: resistance to insulin.