Ahola M, Vapalahti K, et al. Early weaning increases aggression and stereotypic behavior in cats. Sci Rep. 2017 Sep 4;7(1):10412.
The appropriate age to wean a kitten is a subject of some debate. The long-standing dogma for many veterinarians is that a kitten can be weaned onto solid food as early as 4 weeks, and can be separated from the mother at 6-8 weeks. Other veterinarians and groups have favored later weaning due to perceived benefits to health and behavior. It is well known that early weaning causes decreased immune function, increased behavioral issues, stereotypic behavior, and other concerns in many species of pet, farm, and laboratory animals. Stereotypies are compulsive, repeated behaviors performed by anxious animals that have no personal benefit (ie feather plucking in birds, pacing in tigers, cribbing in horses).
A multiple-choice online questionnaire was given to owners of domestic cats in Finland. This included questions about activity level, tendency to seek human contact, shyness towards strangers, reactions to novel stimuli, and aggression towards family members, strangers, and other cats. It also asked how much the cat licks, bites, and sucks itself and how much it bites, sucks, or eats wool or plastic. They were then asked to define if their cat had a “behavior problem”. Owners provided their cat’s age, sex, and breed; presence of other cats in the household; and access to outdoors. Finally, cat owners reported the weaning age of their cat as: before 8 weeks, 8–9 weeks, 10–11 weeks, 12–13 weeks, 14–15 weeks, 16 weeks to 1 year, adult, not weaned at all, or weaning age unknown. The authors considered cats weaned before 12 weeks as “early weaned”, from 12-14w as “recommended age” and after 14 weeks as “late weaned”.
7397 surveys were returned, and 5726 were included in the analysis. These cats represented 40 breeds, and included 4925 that sucked wool (32%), 5683 excessive groomers, and 5550 for reported to have behavior problems according to their owners or a veterinarian. 41% had some degree of inter-cat aggression. Cats exhibiting evidence of one stereotype were likely to show signs of others.
When comparing behavioral problems to age of weaning, cats weaned before 8 weeks were significantly more likely to exhibit aggression toward strangers than cats weaned at 12-13 weeks. Cats weaned after 14 weeks were the least likely to be aggressive. Cats weaned in adulthood were significantly less likely to show shyness towards new objects, and were also less likely to exhibit overgrooming or wool-sucking. Owner reported behavior issues were more prevalent in early-weaned cats than late-weaned cats.
The authors concluded that early weaning is associated with an increased risk of stereotypic behaviors, aggression, and behavioral problems, and that weaning at a later age (ie at or beyond 14 weeks) would be recommended to reduce the risk of behavior issues.
The results of this study fairly convincingly suggest that weaning cats at a later age will prevent or reduce stereotypies and aggression later in life. This is likely due to increased socialization, discipline from the mother, and developing inter-cat skills with littermates. That said, there were several drawbacks to this study. While the sample size was large, the study was survey-based and retrospective, introducing substantial room for bias from owners. Also, while the recommendation for late weaning may be an option for owned, intentionally bred cats, it may be difficult to follow in shelter environments or for orphaned kittens, where earlier weaning and rehoming is desirable due to capacity issues and ability to provide care. A weaning age as late as 12-14 weeks may be better for the long-term behavioral health of cats than previously suggested earlier ages, and should be followed where possible. (MRK)