Disorders of Ingestion Behavior

4. Disorders of Ingestion Behavior

In the owner’s mind, feeding behavior is associated with health, well being and pleasure, especially in mature markets where anthropomorphism is strongly present. This is probably why so many clients regularly question veterinarians about the relationship of food intake to some disturbances.

We will distinguish qualitative troubles (plant eating, pica and wool sucking, fixation on one food, learned aversion) from quantitative troubles (hyperorexia and anorexia).

Nepeta cataria (catnip plant) The catnip plant is usually well appreciated by cats. It is a generic name that applies to various plants sold for cats. (© Olga Struk/Fotolia.com).

Qualitative Disorders

Grass and Plant Eating and Catnip

Cats frequently eat grass if they have access to it and/or they may ingest house plants. Plant ingestion may be considered as a natural phenomenon which makes vomiting easier and thus the expulsion of hairballs. It becomes a behavioral issue when addiction occurs, i.e. if a cat systematically seeks a specific plant.

The catnip plant (Nepeta cataria) often induces a reaction in cats. Not all cats respond to catnip: 30-50% of cats do not respond at all and the response appears to be inherited and modified by both age and experience (Beaver, 2003). When exposed to catnip a cat who responds will usually smell it, lick it, chew or eat it. The cat may hold the catnip in their paws if it is fresh. Cats will often roll in the plant. Some cats become quite animated and leap and play. The sequence is accompanied by head shaking, rubbing of the cheek and chin against the plant and profusely salivating. This may be perceived by an unexperienced owner as an estrus-like behavior. The response lasts 5 - 15 minutes and cats may be refractory to catnip exposure for about an hour. This is a sort of satiation phase following the excitment. The active component, or at least the most powerful one, is a nepetalactone, a terpenoid with a special attraction effect to female cats (Sakurai, 1988).

Valerian (Valeriana officinalis) produces similar effects to catnip. Cats roll on roots, urinate over it and exhibit signs of great excitement. After chewing the plant, the cat will roll for 10 - 15 minutes on the floor, rub against objects and exhibit estrus-like behavior.

Actinidia (including chinese gooseberry): when presented with this plant, the cat stops eating and even stops sexual activity. On detection of the smell, they will seek its origin and roll on their backs in a state of total ecstasy.

Olive Wood. Most cats chew and lick olive wood objects and rub at them. Olive flesh is not attractive to cats, it is more the nut.

This attraction to plants may become annoying and more importantly, as many house plants are poisonous, can have serious consequences when ingested. In addition, most owners find the consumption of houseplants objectionable and punish the cat for doing so if they catch the cat in the act. This can often result in a cat that is frightened of the owners. Treatment aims at providing acceptable plant material for ingestion by creating a cat garden of grasses (sold in many petshops) and plants that are acceptable and safe for consumption by the cat. Other plants should be placed out of reach either high off the ground, secured in another room or outdoors. In some cases making the plants aversive using hot-pepper solutions sprayed on the leaves or a water sprayer if the cat gets too close diminishes the behavior.

Pica and Wool Sucking / Chewing Behavior

Pica

Pica refers to the voluntary ingestion of non dietary, non nutritional items and can include clothing, electric cords, wool, fabric, cardboard, plastic and many other items. Some cats may actually ingest the items and intestinal blockage is possible.

It represents between 5 to 10% of behavioral problems in cats. Often pica occurs in young, active animals and in some cases a genetic predisposition is suspected but has not been proven (Beaver, 2003). It is important to keep in mind that kittens actively explore orally their environment up to 6 weeks of age and voluntary intake of unedible items can occur without being pica. Beyond that, special attention is due.

The origin of pica is in fact not very well known. Some mineral or vitamins deficiencies had been incriminated in the past, but the tremendous formulation improvement of cat food has eliminated this possible theory. Massive parasitism may be a similar contributing factor in farm cats.

Medical conditions such as feline leukemia and feline immunodeficiency should be investigated since they may contribute to abnormal behaviors. In dogs, exocrine pancreatic insufficiency has been associated with pica, but that has not been noted in the cat (De Braekeleer et al, 2000). In other situations a lack of an enriched environment, dental problems, teething, attractive odors on objects and attention seeking have all been considered as contributory factors for pica.

Pica is thought to first be exhibited in situations of conflict and/or anxiety for the pet. In cats the initial situations may be social situations between cats, changes in social interactions with family members, moving house, etc. Over time the problem behavior occurs in other situations and more frequently until it interferes with function. Diagnosis of a compulsive disorder is based on exclusion of other causes for the behavior.

Wool Sucking

Wool sucking has to be distinguished from true pica. This behavior is considered to be a compulsive disorder (Luescher, 2002). Wool sucking occurs when a cat takes clothing items, usually woolens (but other fabrics may be chosen) and sucks or chews. Some kittens are naturally sucking their littermates or their own skin: later, this habit can extend to other species, cushions, or the owner’s clothes. Under natural conditions, kittens can suckle their mother up to 6 months of age. In domestic conditions, weaning is earlier (6 to 8 weeks). Houpt(1982) hypothesized that it was the result of a suckling deprivation as a consequence of early detachment, however, nothing has yet been definitively proven. The strong or excessive affective link with the mother and with the owner (in oriental breeds) may also be part of the explanation.

Because Siamese and Burmese cats are over-represented up to 8 months of age; a genetic predisposition toward wool sucking is suspected but not yet proven. (© Renner/RC/Siamois).

Treatment

Treatment of pica and wool sucking includes a mix of the following strategies:
- In some cases merely keeping the pet away from items is useful.
- Making items aversive with unpleasant smelling or tasting detergents: garlic or red pepper mashes, aloes, quinine, strong perfumes (avoid chlorinated agents which attract cats)
- Redirect the cat to other items: increasing feeding opportunities through the use of feeder type toys may help.
- Keeping the materials out of reach (Houpt, 2005), when possible
- Offer derivations to the cat, such as toys, possibilities to go out for a walk or a hunt
- Behavior modification, creating a predictable and reliable environment avoiding anxiety sources
- Restructuring the interactions with the owner, by discouraging over-attachment syndrome (regular and increasing separation phases from the owner, compensated by physical contacts initiated only by this latter while ignoring cat solicitations: it is hard to get observance but it is efficient)
- In some cases use psychotropic medication e.g., a Selective Serotonin Reuptake Inhibitor (SSRI) such as fluoxetine or a tricyclic antidepressant (TCA) such as clomipramine (Luescher, 2002).

Fixation on One Type of Food and Neophobia

Neophobia is the opposite of neophilia and corresponds to avoidance of a new food compared to the usual food. Also called "fixation of food habits", neophobia has been identified in cats. This behavior is part of a food selection strategy.

Omnivorous animals consume foods that provide a balanced diet and avoid taking the risk of eating new unknown foods. However, carnivores in the wild display more neophilic than neophobic behavior (Thorne, 1982). Neophobia is more common when meals are served in unusual conditions (Thorne, 1982) or if the animal is under stress (Bradshaw, 1991).

It is not uncommon for a cat to become fixated on a particular type or flavor of food and reject all others. Often this can be prevented by offering a diversity of flavors and textures of appropriate complete and balanced diets when the cat is young. Willingness to try new foods and food preferences may be influenced by the queen and the weaning conditions: kittens fed since weaning with the same cereal-based food preferred this type of food to more palatable canned food with tuna (Wyrwicka & Long, 1980). Neophobia, the lack of recognition of food as being edible (Bradshaw et al, 2000), exists in varying degrees. The more regular the diet, the more persistent is the neophobia.

In some cases it may be medically necessary to switch a cat to a new diet. If the diet texture and shape are the same as the previous one, the cat may accept it readily by adding it step by step in the new food while decreasing the proportion of the old food over a week of time. For some cats, offering the new food and old food side by side will also help the transition. In other situations, a cat may need to be transitioned from a canned food to a dry food or vice versa. This is often difficult since many cats seem to have preferences for certain shapes and/or textures of food. Increasing the smell may enhance eating for some cats and this often can be accomplished by warming the food.

Three Approaches Which May Help Overcome Neophobia

1. Offer the new diet each day for at least three days (offering fresh food each time). Persistent exposure, even if the cat initially refuses the new food, may help overcome neophobia.
2. Try putting a small piece of the new food in the cat’s mouth, so that the cat can taste the new food.
3. If the diet is a wet food (can or pouch), try smearing a little of the food onto the cat’s front legs. Most cats will lick off the food and this can habituate the cat to a new food.

A few days are required to overcome neophobia and for an animal to experiment with the new food (Cheney & Miller, 1997). To overcome neophobia towards a new flavor, cats should not be exposed to the smell alone; they must also taste it. In a study on cats, Bradshaw(1986) showed that neophobia disappeared after the third day of presentation of food flavored with lamb. Neophobia reappeared three months later if the cat was not regularly exposed to the new flavour. One solution devised to overcome neophobia towards a flavor involves using drinking water as a support. Although neophobia toward new foods is common in many species, neophobia toward flavored drinking water is indeed rare.

Introducing a new diet under unusual circumstances or when a cat is stressed (by pain or illness, by being away from its owner, in a veterinary clinic etc) is more likely to result in neophobia (through an aversion learning process) than if the new food is introduced under familiar, positive circumstances. It is recommended to always introduce a new diet under the least stressful conditions for the pet and use a food transition program.

Learned Taste Aversions

Aversion is a strategy used by animals to avoid foods that are unsuitable for them. It is a form of negative conditioning. If the smell of food is associated with distress, with an unpleasant experience (hospitalization, forced or hidden drug administration) or with a digestive problem (poisoning, allergies), the food will be avoided in the future. This phenomenon is known as aversion (Cheney & Miller, 1997).

In cats, aversion sets in very quickly. A single meal associated with unpleasantness leads to a refusal to eat. Such aversion can persist for 40 days (Bradshaw et al, 1996) or more (Mugford, 1977). The smell alone of a food associated with digestive disorders is enough to elicit aversion. Cats even go so far as to show aversion for their usual food if it is served in the presence of an air current bearing the odor of a food to which they have developed an aversion (Mugford, 1977). Be careful when preparing foods for cats being boarded at the hospital. Odors may travel and could trigger an aversion reaction even in cats being fed their usual diet. It is best to prepare the food in a place where food odors cannot reach the cats.

Quantitative Disorders

Polyphagia

It is crucial to remember that feeding is an affective and rewarding act for the owner. It is the moment of the day during which the owner can get attention from the cat. However owners have to understand that the dietary behavior of cats is different from humans. For humans, the kitchen is often a social place. Cats like contact and will therefore go to the kitchen just to share social interactions. These requests for interaction are misinterpreted by the owner as begging for food. Owners do not recognize food soliciting behavior as an attention seeking behavior, not hunger and provide the cat with too much food which it willingly consumes. Most cats are obese because they are provided with a highly palatable, energy rich diet in excessive of their metabolic needs. Starting out with a good feeding routine and pattern may help prevent obesity (Table 5).

It is important to remember that neutering is responsible for decreasing energy expenditure. The balance between energy intake and energy requirements is usually disturbed after neutering.

Pathological and Medical Reasons

If the cat consumes excessive amounts of food without gaining weight then a metabolic problem (such as hyperthyroidism, pancreatic insufficiency, diabetes mellitus), massive parasitism or sometimes brain tumors, should be considered and a full medical evaluation obtained.

Some drugs such as diazepam, megestrol acetate and corticosteroids may also induce polyphagia (Table 6).

"Hypersensitivity / Hyperactivity Syndrome"

Some European behaviorists recognize a syndrome of excess food intake which may be due to lack of self control. Kittens scratch, bite, run everywhere and play constantly. Owners are impressed by the amount of food eaten without becoming fat. Some cats gulp their food, eat it quickly and then regurgitate it. This syndrome is due to a lack of mother regulation between the 5th and 6th week. This often happens when adopting young kittens from an outdoor life, that are not handled and not well fed during this crucial period of their life (Beata, 2007).

Social Problems

A cat may consume large quantities of food if it is anxious due to overcrowding, tense social relationships between cats in the home and lack of privacy while eating. Some kittens coming from large litters can maintain the habit to overeat to compensate for competition to the access of food, even when they are later in a single cat household, without competition.

If the problem of excessive food consumption is due to social problems between cats within the home, some simple environmental manipulations can be useful. Food and water bowls should be provided in all areas of the home, after paying special attention to which cats frequent what areas and where they spend their time. Some cats may be more agile than others and the provision of food bowls on elevated locations may allow them to eat with privacy. If one cat consistently eats more than its share of food, then set feeding times and separating cats for feeding may allow all cats to eat their required allotment.

Anxiety

The cat that is permanently looking for food may meet the European criteria for bulimia which can be a symptom of permanent anxiety. The excessive eating and food seeking are a substitution activity for frustration or conflict. If anxiety is the source of overeating then the individual conditions causing anxiety must be addressed (changes in schedules or territory organization, etc.). These treatments are beyond the scope of this article but are detailed in other sources (Horwitz, et al, 2002).

Excessive Food Solicitation Behaviors and Overfeeding

When cats become hungry they may engage in bothersome food solicitation behaviors. These can be especially problematic if the cat does not have access to the outdoors to hunt, or if food is provided in a meal format or set amount daily to prevent obesity. In an attempt to get noticed, food solicitation behaviors include vocalization, climbing, jumping, running, even destruction or agressivity (especially when meal feeding is chosen vs ad libitum distribution, creating some food frustration). Often these behaviors occur during night time hours, waking their owners. In an attempt to placate the cat many owners will get up and feed the cat. Unfortunately, although the cat will stop bothering the owner after being fed that time, the act of feeding the cat when they are noisy will result in the behavior continuing since the cat has been successful, i.e. they received food. The reward (food gift) is indeed reinforcing the undesirable behavior.

Owners need to be counseled on how to avoid giving into demands for additional food. First, they must realize that not all vocalization (even that which occurs in the food preparation area) is a request for food. In some cases, it is just a request for interaction such as petting, grooming or play. A lot of owners wrongly interpret some marking behaviors (such as rubbing against the legs) like begging and they fill the bowl! They will effectively think they were right because they see the cat grabbing some kibbles in a very short meal. This will install a nibbling feeding habit in the cat that can eventually facilitate the development of obesity. If the owner responds to these solicitations with food, then food solicitation behavior can become a ritual, helped by the same reinforcement process explained in the previous paragraph.

Feeding the cat on a set feeding schedule allows owners to control food intake. The daily amount provided should be calculated so that the proper amount is fed daily. In some cases providing the food in a food dispensing toy (Figure 9) will slow down the rate of consumption and perhaps increase satiety thereby helping to decrease food solicitation behavior.

Figure 9. Examples of food dispensing toys. (© D. Horwitz).

Daily play sessions limit the risk of obesity. Research has indicated that cats may quickly tire of a toy and the intensity of play diminishes within a few minutes. However, the presentation of a new toy stimulates the return of play (Hall et al, 2002) (Figure 10). Exercise can also be increased by placing food bowls at distant locations requiring the cat to walk longer distances to obtain food.

Figure 10. Cats need to be stimulated by new toys to encourage play behavior. (© Chataignier).

Globally, two methods are employed to stop excessive food solicitation behaviors:

1. To ignore the cat and stop feeding the cat on demand, a process called extinction. When the owners attempt to do so, the cat will usually escalate their attempts for a few days, before it decreases. This intensification phase is hard to manage for owners. They must be aware of such process and must hold out. With time, they will finally see a decrease in the demands. To facilitate success in this intensification phase, the owners can also either confine the cat to an area where they cannot hear it, or interrupt the behavior with a noise stimulus that discourages the cat from continuing.
2. To provide food in a way that is not connected to the owners using a timed feeding system. Electronic feeders that operate on a timer can be programmed to provide food at a set time each day and the cat may learn to wait until that time to be fed. In other cases, the feeding time must be slowly manipulated to teach the cat to eat at a later time each day.

Habits have to change to stop the reinforcement process. The owner may change the meaning of some daily situations or clues to play, petting, walking etc.

Finicky Eating Patterns

Many pet owners complain that their cat is finicky and eats poorly. While many medical problems can influence hunger and subsequent food intake, these will not be considered here. Only the behavioral issues will be discussed, although all cats with suspected diminished appetite should undergo a complete medical and dental evaluation.

In certain cases a cat may refuse food from time to time simply because they are overfed, not hungry and/or exercising self-regulation of intake. Many new owners are unaware of the nibbling pattern of cat feeding behavior. Other cats may show finicky behavior due to excessive rotation of dietary choices. In other cases the cat has learned that waiting and not eating will result in a different, perhaps more desirable food choice being offered. It is important to take time to explain that too many changes in food varieties or giving treats can be harmful for cats.

The first step is to evaluate the actual amount of food provided daily and the actual amount consumed by the pet. This must also include all treats and human foods provided to the pet. The pet must be weighed: cats that are of normal weight and maintaining their weight over time are usually consuming adequate nutrition to maintain body weight. Body condition score should also be assessed. If the cat is obese then finicky behavior is not a nutritional problem, rather an emotional and behavioral one.

Once any underlying medical and dental problems have been identified and treated, behavioral treatment strategies can be employed. Daily caloric needs should be evaluated so that they can be met. The appropriate amount of food that should be provided daily to meet the animal’s nutritional needs should be calculated for the owner. Often this is less than the owner has been feeding and this simple reassessment can help the owner understand that the cat is consuming adequate amounts of food. For many animals, setting a feeding routine is useful. The food should be provided at the same time daily in a quiet location and with each cat having its own bowl. Limiting treats can also help increase the desire to eat the provided commercial preparation.

Feeding diets that have increased levels of fat will allow for more nutrition with each mouthful. Excessive attention at meal times should be avoided since this can increase finicky behavior if it becomes an attention seeking tactic. Regular follow up both to weigh the pet and discuss progress with the owner should be scheduled to assess improvement and keep the treatment program on track.

Body weight of a finicky cat should be assessed. If the cat is obese and if no disease is suspected, you can hypothesize that the cat may obtain food from additional sources (perhaps from a neighbor, another pets food etc). (© Royal Canin)

Anorexia

Anorexia is defined as a diminished appetite. It is associated with many disease processes, trauma and psychological disturbances. In complete anorexia the animal does not eat at all. In partial anorexia the animal may eat some food but not enough to meet its metabolic requirements.

Although it is often the reason for consulting the veterinarian, anorexia can result from either an organic or behavioral pathology. It can be due to:

- Illness such as fever syndromes or cancer (anorexia may appear before tissue destruction and is the result of tumor metabolites).
- Any parodontel disease (creating pain), face or jaw trauma (leading to an inability to eat)
- Loss of olfaction: anorexia will last as long as the olfactory mucosa is not restored (renewal needs 4 to 5 days after the destructive agent has been removed)
- Psychological stress (depression in reaction to the absence of the owner, even loss of close companions) or physical stress (e.g., excessive handling) (Beaver, 2003): anorexia is accompanied by behavioral escape and withdrawal, house soiling, inhibition of play and exploration.
- Anxiety triggered by social stress (antagonistic relationships between household cats, schedule changes, new household members (human or animal )
- Anxiety that occurs with transportation, boarding or hospitalization (which can lead to specific learned aversion associated with the diet given during the event).

In multiple cat homes partial anorexia may be ongoing especially if the social situation creates anxiety, stress and aggressive encounters between cats. If food and water bowls are not placed through out the environment, some cats may be unable to access them except at odd times. Even then, they may risk being attacked by other cats within the home for entering their territory. Understanding how the cats use the space provided to them and where various cats spend their time within the space provided can indicate where food, water bowls and litter boxes should be placed. Owners may need to be educated on aggressive interactions between cats. Not all aggressive interactions are overt (hissing, growling, chasing and fighting) but in many cases the actions are covert such as staring, blocking access or displacing the cat from resources (Table 7).

In cats that are anorexic for more than 4 to 5 days, early intervention is suggested. Meal feeding in quiet, dark

locations may help some individuals. The use of pheromone diffusers may calm some cats and increase food consumption both in the home and in the kennel or hospital situation, by their appeasing effects. Griffith et al (2000) found that both well and ill cats exposed to the pheromone showed increased interest in food and eating and increased grooming. In the second phase of the same study, cats exposed to the pheromone and a cat carrier showed significant increase in food intake over 24 hours compared to cats exposed to pheromone alone. Providing secure quiet locations, hiding spots within the cage or kennel and pheromones may therefore help increase eating in some hospitalized and kenneled cats.

When anorexia becomes profound, medical intervention is required. In the early stages some individuals may respond to benzodiazepines which may stimulate appetite. Diazepam however has only a transient effect (3 to 4 days) and acute hepatoxicity is often a serious risk. Mianserine has a quick orexigenic effect, but leads to some desinhibition to be controlled (Coupry, 2007). Food should be nearby after administration in case the cat shows interest in eating. Cyproheptadine has also been used in some cases to stimulate appetite. Progestins and anabolic steroids have been tried in the past but, due to potential adverse side effects, they are not recommended and rarely used. Should anorexia persist, enteral feeding tubes need to be employed to allow for supplemental nutrition until the cat recovers and begins to eat on its own. Forced feeding presents however a disadvantage: digestion and absorption are indeed incomplete compared to voluntary eating (food intake stimulates the cephalic phase of digestion which can account for up to half of the gastric acid production).

To summarize, the following simple actions can help solve the problem (Rabot, 1994):
- Pay attention to any causes of uncomfort (dirty bowl, noisy place, strong smell of litter box, feeding spots with frequent passage, air flows)
- Warm the food to 38 - 40°C (instead of receiving the canned portion directly out of the refrigerator)
- Move the bowl to a quieter place (by looking at the cat activity program and locating preferred spots) or separate each cat (to avoid rivalry), at set times
- Introduce a novel and very palatable food (the effect only lasts 2 to 3 days), in a sudden way, or spread over several days by increasing proportions into the daily ration
- Attend meals for strongly dependent cats or put some food on the fingers to make them linked (especially in the case of reactional depression, but beware of the risk of ritualization)
- Ensure renewal of canned food (to avoid oxidative and bacteriological damage).

One must remember that the efficacy of these recommendations may vary between cats and situations. Felines are rarely deceived and often stubborn.