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Internal and External Influences on Disease Risk

Stress is a term that describes the interaction between organisms and their environments. Stressors are events and changes in a cat’s life that may affect its well-being, including both internal (e.g., injury, infection, inflammation) and external (e.g., environmental instability, the perception of threats) stimuli. Cats’ health and welfare needs can be more readily appreciated with a better understanding of their evolutionary behavior. Moreover, some cats are unusually sensitive to their surroundings, and may respond to stressors by becoming uncomfortable, nervous, or fearful. Particularly susceptible cats may develop behavior problems (eg, aggression, house soiling) and/or health problems.

To understand what may activate the stress response system (SRS) in cats, one needs to understand how cats behave in their natural environment. Even when a cat lives indoors, its behaviors result from adaptive survival strategies in the wild. In their natural environment, cats hunt for food, hide from predators (often by climbing), and defend their home territories. Indoors, these behaviors may look hostile (biting and scratching) or “spiteful” (climbing and marking).

Not Like Other Domestic Animals

Cats, unlike dogs and other domesticated animals, are not pack or herd species. Pack species include predators that mostly hunt large prey in groups and large prey species such as cattle and horses that live in groups for self-protection. In contrast, cats are solitary hunters of small prey. This developmental strategy has resulted in important differences in cat behavior, which have been carefully studied. Our understanding of the roots of cat behavior can help improve the environment for cats and decrease stress.

Cats use a combination of senses in order to communicate, favoring a significant reliance on smell to communicate with other cats, locate food, and detect predators. Cats communicate by “marking“ objects and other animals with scents (pheromones) that are released from glands located in the forehead, cheeks, tail base, and paws when they scratch and rub themselves on objects. Vocal communication also plays a significant role in cat-to-cat encounters. It is important to note that cats do not understand human language and the significance of our verbal interactions with them may not be as straightforward as we presume.

Stress Responsiveness and Disease Risk

Although many indoor-housed cats acclimate successfully to a wide range of surroundings, the neuroendocrine abnormalities found in cats presented for treatment of feline idiopathic cystitis (FIC) seem to point to a reduced adaptive capacity. The urinary bladder is only one of the organs involved in multiple complex abnormalities of the nervous and endocrine systems. Case control studies have found multiple organ involvements in cats with FIC, and studies of environmental enrichment have found beneficial effects on some organ systems and behaviors.

An enhanced central noradrenergic drive in the face of inadequate adrenocortical restraint may act to maintain the chronic disease process in these patients, driven by an increase in hypothalamic corticotropin-releasing factor (the outcome of a dysregulated developmental process). Because of these abnormalities, treatment strategies that decrease central noradrenergic drive may be important in reducing signs of FIC and related disorders; those that do not address this seem to be less effective. Until more effective treatments to normalize responsiveness of the SRS are available, efforts to reduce input to this system by environmental enrichment seem reasonable.

Stress and FIC

Cats with FIC appeared to have increased activity of the SRS and decreased adrenocortical function in response to stressful circumstances. As mentioned above, external factors (e.g., aggression by other animals) have been shown to unmask susceptibility in cats to other common chronic diseases.

Evidence from a variety of studies suggests that FIC in some cats is more likely to be a systemic disorder affecting the bladder than an intrinsic bladder disease. In these patients, FIC may be more comparable to the effects on the bladder of diabetes or spinal cord injury than of a urinary tract infection or bladder tumor. That the clinical signs of all these (and other) conditions are similar may be related more to the limited number of responses the bladder is capable of mounting rather than to the location of the insult.

Patients with FIC seem to have variably severe involvement of the SRS (internal factors) and exposure to a range of stressful environmental stimuli (external factors). Given the current state of our knowledge, we have limited capacity to treat internal factors, thus focusing on modification of external factors pending development of more effective strategies to modulate the activity of the SRS.

Keys to Enjoying Cats in Our Lives:

Provide acceptable outlets for their natural behavior
Reduce their exposure to threats

The impact of Stress on Cats:

Recurrent Urinary Problems
Dermatologic Conditions

Recommended Environmental Enrichment to Reduce Stress:

Avoid punishing the cat and remove threats
Change diet to canned food if acceptable to the cat and owner
Increase water intake resources
Change litter to an unscented, clumping variety if acceptable to the cat and owner
Institute improved litter box management
Provide climbing structures, viewing and resting perches, and scratching posts
Provide audio and video sensory stimulation when owners are absent from home
Increase client interaction with the cat
Identify and resolve conflict in multiple-cat households
Add pheromones* (Feliway®) to the environment

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* Adding pheromones is another way to enrich the environment. Feliway®, a synthetic analog of a naturally occurring feline facial pheromone, is designed to decrease anxiety-related behaviors in cats. It has been reported to reduce the anxiety experienced by cats in unfamiliar or stressful circumstances,nine a response that may be helpful to stressed patients and their owners. At our clinic, we recommend environmental enrichment as a preventive for all cats, just as we recommend appropriate vaccination and provision of satisfactory nutrition.

CA Tony Buffington, DVM, PhD
Ohio State University

Happy, Healthy Cats: How to Minimize Stress in the Modern Domestic Environment

Many natural feline behavior systems are compromised in a domestic environment. Cats often find themselves living in groups of unrelated individuals, made to share important resources, and denied the opportunity to hide or retreat from potential conflict. Their human companions also make social demands that are at odds with their natural behavior and often fail to provide for many of their basic instincts, resulting in significant stress and tension. An understanding of feline ethology helps explain how problems develop and offers practical solutions. It is increasingly recognized that stress can be a major factor in the onset and progression of medical conditions; therefore, ensuring that the domestic cat is as well adapted to its environment as possible is an important element of preventive medicine.

The Challenge of Multicat Households

A significant increase in the popularity of the cat and the increase in the number of multicat households have introduced new pressures on feline well-being. Whilst households made up of sibling pairs, mothers and offspring, and other combinations of related individuals can do well, new cats are often mistakenly acquired as companions for already resident felines. There is no basis for toleration between these unrelated individuals, although neutering can reduce hostility and enhance chance of integration. Aggression and tension among housemates may manifest as outright physical confrontation and injury but more commonly feline tension can result in subtle signs of unease and cause chronic low-grade stress. This in turn contributes to obvious behavioral issues (eg, marking, overgrooming) but may also be a significant factor in medical conditions such as feline idiopathic cystitis (FIC).

Human Demands on Feline Companions

An important source of feline stress is the effect of changing human expectations on the behavior of this ideal modern pet. The human desire for low-frequency/high-intensity interaction raises very specific challenges for the cat. The natural basis of feline social communication is high frequency/low intensity. This fundamental difference in interaction style can lead to considerable tension. The cat’s primary defense strategy is flight, and the human tendency to pick up cats and cuddle or restrain them can be potentially threatening.

Preparing Kittens for the Domestic Environment

The successful integration of kittens into an average human household requires a certain amount of preparation. Although genetic influences help determine how each individual reacts to novelty and challenge, adequate early exposure to a diversity of stimuli will be crucial in ensuring that a cat has a broad range of experiences with which it feels comfortable. Lifting, gently restraining, and touching a kitten all over its body should be routinely incorporated into any program of early development. It is important, however, to respect a cat’s natural reserve and keep highly restrictive handling to a minimum. Inherited boldness, a complex and secure early environment, and ongoing mental and physical stimulation in adulthood will benefit most cats and can prevent behaviors that could compromise their lives as human companions.

Minimizing Feline Stress

Studying feline territories illustrates the importance of things like privacy, choice, and hygiene. The golden rule in feline society is that cats need to have free and immediate access to essential resources at all times and perceive themselves to be in control of their environment. Access to vertical space is important for the natural feline coping strategy of minimizing fear and anxiety by climbing. Failure to cater for the natural defense strategies of flight and hiding can result in cats feeling threatened, resulting in chronic stress and inappropriate self-appeasement behaviors such as over-grooming and overeating. Simple alterations such as providing bedding in high places can make a considerable difference in their environment. In situations where anxiety is causing obvious behavior changes, the addition of a pheromone diffuser can be beneficial (Feliway®). Social tension within local neighborhoods because of higher population densities of cats in urban areas is more difficult to remedy.

Natural Feeding Patterns

A policy of ad libitum feeding rather than a rigid “2-meals-a-day” routine makes more sense according to natural feline feeding patterns. Feline anatomy and physiology and hunting behavior all favor the consumption of numerous small meals per day. The ratio of hunting energy expenditure to energy consumption is high, leading to very effective natural weight control. When food is provided without any need for effort, the balance between energy input and output is altered and unsuccessful weight control may result. Caring owners may misinterpret snacking behavior as a sign of not liking the food and mistakenly offer more palatable food at each “meal,” thereby increasing the risk for obesity.

Adequate Mental and Physical Exercise

Ensuring that cats expend sufficient mental and physical energy during the day is important for weight control and physical and mental fitness. Cats are designed for short bursts of energy-consuming activity (often related to predatory behaviors) interspersed with significant periods of rest and relaxation. Misdirected predatory behaviors can contribute to increased stress and frustration-related behaviors.

Feline Hygiene Preferences

Development of fastidious toileting habits is adaptive for survival, minimizes the risk of transfer of parasites and infectious agents, and reduces the ability of predators to locate territories through the fecal scent. Feline attention to cleanliness is one of the most positive aspects of cat behavior for many owners – most kittens are already house-trained when they arrive in their new homes. However, provision of appropriate elimination facilities is a prerequisite for acceptable and appropriate hygiene. Latrine facilities must provide all of the qualities a cat would require in the great outdoors, along with adequate privacy. Cats naturally choose the periphery of their core territory away from resources such as feeding stations and resting areas. Sites that make the cat vulnerable or force proximity to other resources must be avoided.

Ensuring that the domestic cat is as well adapted to its environment as possible is an important element of preventive medicine.

Sarah E. Heath, BVSc, DipECVBM-CA, CCAB, MRCVS
Behavioral Referrals Veterinary Practice
Chester, England

Implications of Environmental Stress

Behavior problems
Feline idiopathic cystitis (FIC) and abnormalities in the stress response system (SRS)
Reduced immune response and vulnerability to infectious diseases and specific medical conditions (e.g., feline orofacial pain syndrome, feline hyperesthesia, and diabetes mellitus)


Providing a social and physical environment that is compatible with normal feline behavior is essential for preventing both behavior problems and some of the most important feline medical conditions.

Feliway® product highlights:

Contains a synthetic analog of the F3 fraction of feline facial pheromone
Helps prevent or eliminate/ control reactions to stress in cats (e.g., urine marking, vertical scratching, loss of appetite, reduced desire to play or interact)
Provides familiarity to cats in unfamiliar or stressful situations (e.g., adoption, visit the veterinarian, new arrivals, etc.a an)
Availableanelectric plug-in diffuser lasting 30 days or 75 ml spray for local spot application

For more information, visit

CA Tony Buffington, DVM, PhD and Sarah E. Heath, BVSc, DipECVBM-CA, CCAB, MRCVS

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