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How to stop chewing problems in puppies

Veterinary Medicine FEBRUARY 1999:157

Puppy owners can nip this destructive behavior in the bud by providing the right environment and training from the start. In this article, you'll find out how to help owners prevent and, if necessary, treat inappropriate chewing.


Tiertasanta Veterinary Hospital and Veterinary Behavior Consultants

10799 Iierrasanta Blvd.

San Diego. (A 92124

PUPPIES CAN CAUSE an amazing amount of destruction. They can scratch deep grooves into wooden doors and moldings, dig up carefully placed landscaping, or chew their owners' prized possessions. This damage not only is expensive, it erodes the human-animal bond and may even endanger a pet's health.' As with many behavior problems, destructive behavior can often be avoided by providing acceptable alternatives.

This article provides recommendations on how to prevent and treat a common destructive behavior in puppies: inappropriate chewing. Adult-onset destructive chewing, which can be due to a behavioral condition such as separation anxiety, is not covered.

Chewing is a normal behavior that becomes unacceptable when exhibited in the wrong place. Young canids use their mouths and teeth to eat, explore their environment, and relieve stress and boredom. (See "How to manage play nipping in puppies.") And puppies chew more than usual when their permanent teeth erupt.

Moreover, a medical problem can lead to destructive chewing. Pica (eating nonnutritive substances) is thought to result from the same physiologic state that produces emesis, presumably nausea. This correlation was shown in rats that exhibited pica after being given apomorphine hydrochloride, which causes vomiting. So gastrointestinal distress may make puppies nauseated, inducing them to chew and consume inappropriate items in an attempt to feel better. A thorough history and medical workup may be needed to rile out nutritional deficiencies and gastrointestinal problems in puppies that chew excessively.

Steps to prevent destructive chewing

Match the pet to the lifestyle

When choosing a purebred puppy, prospective owners shouldn't simply pick the one with the cutest furry face. They should first investigate the breed's behavioral traits, including its tendency to chew. In addition, veterinarians, pet store personnel, and breeders can help prospective owners choose purebred or mixed-breed dogs that suit their lifestyles. For example, an easy-going person may be annoyed by a highly energetic puppy. Such a puppy is likely to become a chewer and may be restricted to the backyard, where it will probably dig or bark excessively. Eventually, the owner may give up on the puppy and take it to a shelter. On the other hand, young children, active individuals, or a high-energy household may intimidate or stress a quiet or shy puppy. This too can lead to destructive behavior, often as a form of stress release. Finally, a family that is out of the house eight to 12 hours a day may be better off with a different species of pet altogether (e.g. a cat, hamster, or reptile).


How to manage play nipping in puppies

If a puppy's oral behavior extends to nipping and biting, the pet needs to be taught the limits of such mouthing. Unlike chewing behavior, mouthing is usually motivated by inappropriate social play. If the puppy were raised in a pack, its mother and the other adult dogs would not permit such liberties-and neither should people. To prevent or eliminate play nipping, advise owners to avoid using their hands in play unless they are petting their dogs or tossing a toy to be fetched.' Also tell owners to avoid rough play and tug of war. Such activity can excite the puppy, prompting mouthing of the owner vs. chewing on a toy. Instead, advise owners to use toys such as balls and ropes that keep hands at a distance.

Puppy bites necessitate a firm "no" and quick withdrawal of the owner's hand from the puppy's reach. When the owner's hand is withdrawn, the puppy's game no longer works. If the puppy still insists on biting in play, some carefully measured discipline is required. For example, the owner might quickly grasp the puppy's mouth, holding it firmly closed until the puppy relaxes or whimpers for a few seconds. If the puppy interprets that response as play, becomes defensive or overly fearful, or challenges the owner, all such direct punishment must cease. In many cases, leaving the room to socially isolate the puppy for 30 to 120 seconds is enough for the puppy to learn that mouthing is unacceptable.

Owners may also need to put a bitter-tasting substance on their hands, as described for chewing problems. This tells the puppy that hand chewing is unpleasant. Other forms of acceptable puppy discipline include using a squirt bottle or water gun; a shaker can; loud, hand-operated horns; or a head halter.2 These techniques work only if they are handy when needed. It is best to have several options in place wherever the owner and the puppy spend time together. When the puppy's play gets too rough, a deep, firm "no" needs to be followed by an effective intervention. This combination gives the puppy the vocal cue that it has overstepped acceptable bounds and reinforces that its actions will have consequences.

REFERENCES 1. Dunbar I.: Doctor Dunbar's Good Little Dog Book. James and Kenneth Publishers, Berkeley, Calif., 1992. 2. Landsberg, G.: Products for preventing or controlling undesirable behavior. Vet.


Enroll the puppy in a training course

After an owner has chosen the right puppy, advise him or her to enroll it in a puppy training class. You and your staff should be familiar with local classes, their teachers, and the class objectives. These classes usually teach entry-level obedience techniques especially developed for 3 and 4-month-old puppies. As a puppy learns to obey its owner, a bond forms that enhances all aspects of their relationship. Such classes can also help with early behavior problems by providing immediate intervention or preventing behavior problems from becoming more serious or deeply established. And these classes provide a support system for puppy owners whose pets have developed similar behavior problems.

Provide exercise

Puppies need to exercise and play every day. The amount of time a puppy needs for these activities varies depending on the breed. But for most dogs, one or two 15-minute periods of supervised play and exercise are sufficient.3 Owners and pets benefit from this interaction, and it can help prevent undesirable attention-seeking behaviors in puppies.3

Teach appropriate chewing behavior

Owners must also realize that a certain amount of destructive chewing is normal. When motivated by curiosity, stress, anxiety, and boredom or by the need for pleasurable experience, most puppies will occasionally chew something inappropriate. So owners need to provide their puppies with expendable and safe- items to chew. Remind owners that some common household items can endanger their pets and must be kept out of reach. These items include cleaning supplies and antifreeze, poisonous houseplants, medications, toys small enough to swallow, sewing needles, and chocolate. Your staff should be well-versed on common hazards and on where to find more information on unusual ones.

Once a puppy learns that chewing a particular object is pleasurable, overcoming the desire to repeat that act is difficult. So proactively arranging an adverse first experience (e.g. chewing a shoe laced with , an unpleasant tasting but harmless substance) may be useful in dissuading the puppy from trying it again.

To teach a puppy to be trustworthy around its owner's belongings, the owner should supervise the puppy whenever it has access to unacceptable items. When direct supervision is not possible, the puppy should be confined to a safe area. Crate training the puppy provides it with a safe place of its own and protects the environment.4 A crate is portable and can travel wherever the puppy goes, enabling the pet to feel at home in a strange place. A crate should not be used to punish the puppy and does not replace proper supervision by the owner. Tell owners how to use a crate correctly, and remind them not to leave the puppy in it all day.

Several safe chew toys should be provided for a puppy to enjoy both in and out of a crate. These should never be old shoes, socks, clothing, or former household items that can be confused with inappropriate chewing objects. Puppies cannot distinguish between a discarded tennis shoe and an expensive pair of running -shoes. Each smells like the owner and is pleasurable to chew. When the puppy chews something inappropriate, the owner should say "no" in a deep, sharp voice and interrupt the chewing with a distracting stimulus such as a handclap, a shrill whistle, or even a sharp squirt of water from a water pistol. Then the owner should immediately substitute a suitable item. When the puppy accepts an appropriate chew toy, it should be praised but not so vigorously that it forgets the purpose of the reward.

To further the lesson, owners can play a game in which they place an acceptable chew toy in each room. They can then walk into a room and excitedly say "Find your chewy!" and reward the dog when it is successful. In this way the owner can consistently encourage proper chewing selection. While encouraging proper chewing habits, owners must be careful not to turn reprimands into a game. Puppies are masters at converting anything into entertainment. For this reason, owners should avoid chasing an animal that is chewing an unacceptable item. (of course, if the item involved is valuable or dangerous, it will have to be retrieved by whatever means. But even in this case, the owner must be matter-of-fact; use low-pitched, controlled vocal tones; and plan the capture with a minimum of chasing). In general, chasing a puppy has two effects: Either the animal interprets the owner's actions as a wonderful new game, or, far worse, the owner corners the puppy, and it-becomes frightened and resorts to biting to defend itself and the item it possesses. In the first instance, the damage is mild and easily reversible. The owner stops the chase scenario, relaxes, and resumes the distraction and substitution method described above. The more excited the owner becomes, the more likely the puppy is to interpret the owner's actions as a game. In the second case, the owner can create a serious problem of defensive or possessive aggression. This may be difficult to resolve even with the assistance of a veterinary behaviorist. If puppy chewing escalates into aggression, even growling, advise the owner to seek professional help immediately.

What to do if chewing becomes a problem

Pinpoint the cause

Normal puppy chewing escalates into destructive conduct for several reasons. Unfortunately, many people think puppies will outgrow their chewing problems. This is true in some cases but certainly` not all. owners who think this way risk expensive house damage and the prospect of giving up the dog. It is better to address the problem immediately than to wait for it to go away. When misbehavior occurs, the owner needs to pinpoint the cause. Is the puppy getting enough exercise and attention? Is it being taught household rules? Is it receiving too much attention, especially when it misbehaves? Is it getting enough praise and appropriate correction? Is it socially isolated or bored? Is the owner expecting too much too soon (eg. expecting an 18week-old Labrador retriever to refrain from chewing household items)? Any of these factors may predispose animals to anxiety and stress, contributing to unruly behavior.

Anxiety has a variety of causes, such as emotional departures or greetings by the owner or competition for play articles between the puppy and another pet. The presence of more than one puppy is an additional, often overlooked factor in cases of destructive chewing. Puppies will often grab an article in play or start a game of tug of war or a shredding contest with another puppy. They may destroy items they're competing for. Owning several puppies is appealing to some people and has the advantage of providing the pets with companionship; but in such cases the owners must be exceptionally vigilant and committed to training their pets to behave.

counterbalancing discipline with praise

No discipline is effective without counterbalancing it with love, praise, and instruction on what is acceptable within the home. Advise owners to reward their puppies with food treats and praise at least as often as they discipline them. Remind owners to use these tidbits and praise lavishly when the puppy does something the owner approves of. All too often people reprimand a dog for inappropriate behavior and totally ignore reinforcing good behavior. Puppies, like people, thrive on a combination of reward, guidance, and measured correction. Training a puppy for success will dramatically increase the likelihood of a happy puppy and owner.


Discipline the puppy

If normal chewing develops into destructive behavior, an owner can use a number of tactics to correct a puppy. Reprimands should never be excessively harsh. (See boxed text "Counterbalancing discipline with praise.") For a reprimand to be effective, it must be prompt, consistent, and only firm enough to deter the behavior. A sudden, full-intensity but not excessive correction (e.g. a loud, startling noised followed by "No!" and the immediate removal of the object) is more effective than reprimands that gradually intensify as the owner becomes more and more frustrated by the dog's misbehavior (e.g. "Give me that" followed by tugging lightly at the object, which can escalate into chasing and a tug of war). Such reprimands result in habituation to the punishment technique.5,6

When dealing with a problem, owners must remain relaxed and preserve their sense of humor. Correct a puppy while the misdeed is in progress, never after the fact because a puppy's attention span is extremely short. In fact, the best time to reprimand a puppy is when it first shows a definite intent to misbehave. Frequent, excessively harsh corrections or those applied long after the event occurs can create a stressful environment, causing the puppy to chew even more. And when corrections come exclusively from the owner, a puppy may learn to chew only when the owner is not observing it.

Retraining a stealthy chewer

To regain control, the owner needs to return to discrimination training as described above. The owner should begin at square one and make sure the puppy is confined and lacks access to inappropriate objects when unsupervised. If a puppy has developed a taste for shoes, for example, it must be taught that this chewing is inappropriate. To do this, the owner should remove all shoes from the puppy's environment except for one that has been treated to make it aversive. Many commercial taste repellents are available for this purpose, including RO-PEL (Burlington Biomedical & Scientific, Farmingdale, N.Y.), a bitter yet nontoxic, odorless product.' Initially, the chosen aversive substance should be introduced directly to the puppy at full potency so the dog develops a strong aversive reaction. One way to do this is to apply the product directly to the corner of the puppy's mouth, causing the dog to salivate and react adversely to the taste. If an owner uses this technique, he or she should at other times place delicious treats in the puppy's mouth so the dog doesn't develop an aversion to the owner as well as to the foul-tasting product. Once the dog shows an avoidance response, the owner is ready to apply the product to' a shoe. The owner must reapply any bittertasting substance to the shoe frequently enough to ensure that it is always intensely bad tasting. Once the puppy leaves that shoe alone, the owner should substitute other shoes treated with an aversive substance until the puppy is trained to leave all shoes alone. During this process, the owner must have acceptable chew toys readily available as alternatives. These can even be coated or stuffed with something the puppy finds tasty. This helps the puppy distinguish between the acceptable and the unacceptable.

Using booby traps is another effective training technique. With this technique, the environment, rather than the owner, punishes an animal. By helping the puppy recognize an inappropriate object on its own, the positive bond between the pet and owner is protected. Some options for safe booby traps include stacked empty soda cans, shaker cans (empty soup cans with a few pennies in them), Snappy Trainee'" (Innovative Pet Products, Littleton, Colo.), or any of the numerous electronic noiseproducing devices available.' These items can be set to go off or fall, startling the puppy if it decides to chew something inappropriate. If one aversive stimulus is not achieving the desired result, try a different one. These devices are most effective when used in conjunction with other behavior modification techniques and when the owner is at home so they can be reset each time they are tripped. The owner should reset such a device when the puppy is not present. These devices are not a substitution for supervision and training. Once the puppy learns that the couch or shoe fights back, the owner must provide a reassuring presence and an acceptable chew toy. The pet will soon think that the foul-tasting or rigged object is a bad thing to chew on and will look for more acceptable outlets for its chewing needs.

Aversive stimuli should be slowly eliminated, so that the puppy never notices their disappearance. To do this, the owner should renew the aversive substance less often or place the booby traps in less obvious places, removing some of them over several weeks.

Another, more extreme method for treating a persistent chewer is based on taste aversion studies. True taste aversion involves pairing a specific taste with feeling ill (nausea and vomiting) 20 to 30 minutes after the puppy encounters a .flavor. Lithium chloride has typically been used in studies with wolves and coyotes and can lead to a long-lasting aversion to a particular source .8 It is possible to combine a small quantity of this substance with a strong tag flavor (such as saccharin) and apply the mixture to items that are to be made aversive to the puppy. This should cause vomiting and an aversion to the taste. The substance can then be applied to other off-limit objects.9 Apomorphine is available to veterinarians and causes reliable and self-limiting emesis.lo,ll It can easily be given subcutaneously (0.04 to 0.08 mg/kg) or by placing a tiny portion of a tablet in the medial canthus conjunctival sac, which can later be washed out with a balanced saline irrigation or with water. Note that ocular administration can irritate the eye but seldom presents a problem. Apomorphine can also induce vomiting about 20 minutes after the dog chews and tastes unsuitable material. Induction of vomiting, however, may be considered an extreme treatment. I have not tried these techniques and recommend reserving them for severe cases in which the puppy is in danger of injuring itself by repeatedly chewing an inappropriate object.

Although aversive substances and booby traps enable a puppy to learn acceptable habits without the owner in the room, an owner may have to leave a puppy for extended periods. In such cases, it's crucial to initially confine the puppy to a small, safe, indestructible area (e.g. a crate). This ensures the puppy's safety and the house's order and allows for a pleasant greeting upon the owner's return. The owner must ensure that the puppy's needs have been met before leaving it alone: The animal has been fed and watered, has been able to relieve itself outside the crate, and has had a sufficient amount of attention and time for play. Owners need to make their departures and returns as uneventful as possible. A brief obedience lesson before leaving may be helpful. This reinforces the owner's leadership position and reminds the puppy to look to the owner for guidance and approval. As a puppy learns the rules, it puppy should be offered access to more of the house for short periods. But too much freedom too soon can result in costly surprises. As a puppy's behavior warrants it, the owner should gradually increase its access to the house.


I would like to acknowledge the substantial assistance of Carol Harris in writing the early draft of this manuscript.


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