The lungs, iliac lymph nodes, and abdominal organs are the most common areas of metastasis (Morris 2013). A cat with a mammary tumor may have difficulty breathing while at rest, have an abnormal gait in the rear legs, be reluctant to jump up on things, be less active, or have gastrointestinal disturbances. If performed prior to a year of age, ovariohysterectomy results in an 86% reduction in the risk of mammary tumors (Overley et al. 2005).
4.9.1.7 Ovarian Tumors
Ovarian tumors are uncommon and only occur in the intact queen (Klein 2001). They are typically unilateral, metastasis is uncommon, and they become quite large before they are detected. Some ovarian tumors will secrete estrogen, resulting in a prolonged estrus. Unlike in the bitch, hyperestrogenism in the cat is not likely to result in alopecia (Mecklenburg et al. 2009).
Most of the ovarian tumors result in non‐specific clinical and behavioral signs. These signs include a distended abdomen due to tumor size or ascites. The queen may also vomit, be anorectic, appear constipated, urinate frequently, have an increased respiratory rate, or show signs of discomfort when lying down due to the physical size of the tumor putting pressure on other organs.
4.9.1.8 Ovarian Remnant
Ovarian remnant syndrome, as it is in the bitch, is characterized by signs typical of an animal who still has ovarian function after removal of the ovaries. In the queen, if parts of the ovary are left behind, they will revascularize when reattached to the mesentery after ovariohysterectomy and have follicular development (DeNardo et al. 2001). Cats that show signs of estrus following ovariohysterectomy should be evaluated for an ovarian remnant.
4.9.2 Male Feline
4.9.2.1 Cryptorchid
The male kitten is born with both testicles descended. He usually reaches puberty and can breed at six to eight months of age. There is a very low incidence of cryptorchidism in cats. Cryptorchid males will behave as a tom cat, showing a higher rate of spraying, increased incidence of abscesses secondary to inter‐cat aggression, and sexual behaviors. A cat under the influence of testosterone will have spines on his penis. This is a relatively non‐invasive method to discern older neutered cats from cryptorchids and potentially partially neutered cats.
4.9.2.2 Castration or Orchiectomy
Removal of the testicles is called castration or orchiectomy. The behavior of neutered male cats is very similar to an anestrus female. Castration results in a significant reduction in sexually dimorphic behaviors, such as mounting, urine marking or spraying, roaming, and fighting in cats (Spain et al. 2004). Gonadectomy to eliminate or decrease these problems tends to be more effective in cats than in dogs (Hart and Barrett 1973). After castration, male cats also have a decreased incidence of abscesses due to bite wounds.
4.9.3 Normal Sex‐Related Behaviors
4.9.3.1 Marking
Urine marking or spraying is a natural behavior for both males and females and has a different underlying motivation than urination (or elimination) due to a full bladder. It is used primarily as a method of communication between cats. It occurs most commonly in intact males; however, gonadectomized males also mark. While it is somewhat less common, it is not rare for a gonadectomized female cat to urine mark. When gonadectomized animals urine mark inside the home, it is usually believed to be a result of anxiety or distress in response to the agonistic conflict between cats in the home or the presence of cats outside the home.
4.9.3.2 Non‐copulatory Mounting
This is a normal behavior primarily of intact males but will occasionally occur in intact females (Houpt 2005). It is more common in the young intact male housed with other young males (Beaver 1989). If mounting behavior is increasing in the shelter, it is important to attempt to recognize specific triggers and/or motivation for the behavior so that the situation can be avoided or the environment changed as necessary to prevent excessive mounting. This may mean either removing the animal performing the mounting or the animal who is repeatedly mounted. Any change in the social grouping may affect the behavior.
4.9.3.3 Masturbation
Masturbation is not reported as a problem in the cat as frequently as in the dog, although owners are more likely to report it in castrated male cats (Beaver 1989). Female cats under the influence of prolonged estrogen, such as a cat with an ovarian remnant, ovarian tumors, or exposure to human estrogen creams, are more likely to masturbate (Kling et al. 1969). Females who masturbate rub their anogenital area against the floor. They may also vocalize and groom their genital area.
Masturbation in the intact male cat is most common in the laboratory setting. Masturbating male cats rub their perineal area on a surface or manipulate the area with their paws. The behavior becomes pathological when an animal performs it to the exclusion of normal behaviors, such as eating, drinking, and environmental investigation. Masturbation can lead to increased infection or trauma of the prepuce, penis, or vulva.
4.9.4 Effects of Gonadectomy on the Behavior of Cats
As with the dog, there are some concerns that early age neutering in the cat may have some long‐term negative consequences, but far fewer studies have examined the risks and benefits of neutering at different ages in the cat. What is known is that more intact animals are returned to the shelter than neutered animals, so delaying gonadectomy could have an immediate impact on long‐term health due to premature euthanasia. In the animal shelter situation, where the risk of owner non‐compliance with sterilization policy (Alexander and Shane 1994) further increases the burden on shelters and rescue groups, early sterilization of cats remains important.
4.10 Side Effects of Common Medications
Many medications have the potential to affect behavior. When using any medication, its potential side effects must always be kept in mind, and the ways in which those side effects might change behavior should be considered. For example, medications that have the side effect of increasing thirst may result in increased drinking and lead to housesoiling because the animal suddenly needs to urinate more frequently.
Corticosteroids are one of the most commonly used drugs in veterinary medicine. They have a high likelihood of affecting behavior, and despite well‐described behavioral effects in humans, very little research has examined the possibility of behavioral changes associated with the administration of corticosteroids in animals. In studies performed by Notari and Mills (2011; Notari et al. 2015) several behavioral changes were noted in dogs after the administration of corticosteroids. These included nervousness or restlessness, fearfulness, startling, barking, food‐guarding behavior, and irritable aggression. In addition, they were also often less playful and more withdrawn from people and situations. Until more research is performed, reasonable precautions should be used when handling animals who are being treated with corticosteroids. See Chapter 22 for more information about behavioral pharmacology.
4.11 Conclusions
Changes in behavior are likely the first signs of stress, disease, and poor welfare in any animal. The changes that an animal experiences when relinquished or abandoned and