November 2018 - Preparing Your Mare for Breeding Season
Join us this month as our expert, Dr. Madison Seamans, returns to answer your questions concerning your breeding mare and what you should do to prepare her for the season.
Click here to read this month's questions and answers.
Equine Dental Care
- After my horse's last routine dental work with an equine dental veterinarian, he started hanging his tongue out the side of his mouth. Now, several months later, it hangs one-third to half the time out of his mouth. He is 23-years-old and in good health otherwise. I questioned my dentist, but got no explanation. However, some friends have told me a horse's tongue has "bones" that can be broken if the tongue is twisted too harshly. I feel so bad for my horse because his tongue just flaps around. Is there anything that can be done to help him? (View Answer)
It is nearly impossible to diagnose a problem like this without a thorough examination of the horse, especially concentrating on the oral cavity and the head. Although the timing of the appearance of the problem was shortly after dental treatments were performed, the tongue problem may or may not be related to the dental treatments. It is important to know what the muscular tone of the tongue is, and if it is decreased, whether it affects the whole tongue or only one side of the tongue. If there is tongue paralysis, indicating damage to the Hypoglossal nerve, the nerve responsible for controlling muscle function of the tongue, it is also important to know if there are any other nerves affected.
Horses do not actually have bones in their tongue, but the base of the tongue is attached to a group of bones called the hyoid apparatus that surrounds the larynx, or voice box. I have often heard that if a person is too aggressive at pulling on the tongue during an oral examination or dental procedure, a fracture of one of the bones of the hyoid apparatus, usually the stylohyoid bone, can occur. However, I could not find any published case reports in the veterinary literature where this has occurred in otherwise healthy hyoid bones. There are numerous reports of fracture of this bone occurring when there is underlying disease of the stylohyoid bone called stylohyoid osteoarthropathy. The clinical signs associated with this type of fracture are usually related to facial nerve paralysis (eyelid and/or lip droop) or balance issues and not symptoms such as you are describing.
There are other disease processes other than trauma that could also cause protrusion of the tongue including, but not limited to, a foreign body in the tongue (often a needle, piece of wire, wood splinters or grass awns), mandibular fracture, Equine Motor Neuron disease, botulism, nervous system toxins, tumors in the brain or pharyngeal (throat) area and a variety of viral or bacterial infections of the nervous system. Some of these are less likely in your case due to the duration of the problem. My best recommendation would be to have your veterinarian do a thorough examination and possibly run some tests based upon those findings. Only by obtaining an accurate diagnosis will your veterinarian be able to develop a plan moving forward. I wish you good luck with your horse. Bruce Whittle, DVM, Trenton, MO
- I have heard and read mixed info on power vs manual dentistry. What is your opinion on this issue? (View Answer)
This question has generated heated opinions on both sides of the issue. There have been a limited number of research studies that have looked at various aspects of the question but none that have directly compared power versus manual equine dental equipment.
There is concern that power instruments can cause overheating of a tooth. However, a 2005 study from Australia demonstrated that as long as the power equipment is cooled by water or grinding time is limited to 15 to 20 seconds on an individual tooth then the tooth is cooled with water, the temperature rise of the pulp of the tooth is low enough that damage to the tooth is not likely. A second study suggested that lower speeds (<6000 rpm) were less likely to cause overheating of a tooth than higher speeds.
A study using a scanning electron microscope to examine the effects of different rasps on the surface of teeth showed that solid carbide rasps that are commonly used with hand floats actually caused more disruption to the surface of the teeth than carbide chip rasps or a power-driven solid carbide bur. Some of the debris generated from the grinding with the power-driven carbide bur actually served to plug up dentinal tubules exposed on the surface of the tooth whereas the solid carbide hand float left these tubules open. The clinical significance of this is unsure but since the dentinal tubules exist as pathways to the pulp of the tooth, use of hand-driven solid carbide rasps might be more likely to lead to inflammation or infection of the pulp.
The bottom line is that any instrument designed to remove tooth material from the horse has the potential to cause damage. Of more importance than the type of instrumentation used is the knowledge of the person using that instrument. Since power-driven instruments can remove tooth material more quickly, the operator must be careful to not get too aggressive. Before ANY tooth material is removed during tooth floating, a thorough oral examination should be performed to make sure if tooth material needs to be removed and, if so, how much. A thorough oral examination requires sedation, a full mouth speculum, a bright light and either a mirror or oral endoscope to visualize teeth surfaces that cannot be seen directly.
Since you asked, my personal opinion is that, with care, either manual or power dentistry instruments can be successfully used. I personally prefer the smaller cutting surfaces of power-driven instruments because I am able to more precisely remove tooth material in small areas. While I predominantly use power dental instruments, I occasionally need to use a hand float to smooth an area inaccessible with the power instrument. Conversely, there are areas of the mouth I cannot access with a hand float but can with a power dental instrument.
Obviously, there are a lot more considerations about the removal of tooth material during dental procedures in the horse. I have tried to limit this particular discussion to the use of manual versus power-driven dental instruments. Thank you for your question. Bruce Whittle, DVM, Trenton, MO
- My 15-year-old healthy horse has a large skin tag, which hangs down on the inside of his mouth next to the teeth. This was discovered when the equine dentist came last month. My veterinarian has suggested banding it until it falls off and he nor the dentist have ever come across this issue. Any suggestions or possible causes? (View Answer)
From your description, it is hard for me to visualize what you are seeing inside your horse’s mouth. It is important to know whether it arises from the gingiva around the teeth or the mucosa of the cheek. Size, color and texture can also be helpful in assessing a soft tissue lesion like this. Most of the mucosal surfaces in the mouth heal very readily due to the excellent blood supply. For example, lacerations to the cheeks caused by sharp points tend to be healed within a few weeks once the sharp points are smoothed.
My two thoughts would be either an odd laceration of the cheek that freed up a peninsula of tissue that did not heal down in its original position or a neoplastic process. If the flap is a result of a laceration, simple surgical removal should be successful. If the “skin tag” is a result of a neoplastic process, either biopsy or complete excision would be recommended. While relatively uncommon, both benign and malignant neoplasia (cancer) can occur in the oral cavity of the horse. Regardless, in my opinion, biopsy or surgical excision followed by sending the tissue to a laboratory for histopathology (examination of tissues with a microscope) would be the best option. If the histopathology report came back as inflammatory or non-neoplastic, the problem is resolved. If the histopathology report came back as neoplasia, knowing the type of cancer helps determine the next step in the treatment plan. I would rather “waste” a client’s money on a lesion that ends up being inflammatory than end up missing a neoplastic process until it is too late to do anything about it. If your veterinarian is not comfortable with this type of oral surgery, they can consult with a veterinary dental specialist for help or referral. Bruce Whittle, DVM, Trenton, MO
- Can use of motorized equine dental tools cause excessive removal of tooth surface exposing pulp chambers to decay? (View Answer)
Any instruments designed to remove tooth material in horses, whether hand floats or power instruments, can expose pulp chambers in the teeth. Horse’s teeth are much different than human teeth. Horse teeth are considered hypsodont, meaning that they continue to erupt and are subsequently worn throughout the horse’s life until the tooth is worn down to the roots. In order to prevent exposure of the pulp horns during normal wear of the teeth due to chewing, specialized cells called odontoblasts continue to produce a hard dental substance called dentin all around each pulp. This deposition of dentin shortens the pulp horns and decreases their diameter. The dentin deposited between the tip of the pulp horn and the chewing surface helps prevent an accidental pulp exposure during normal tooth wear.
Most of the time when we are floating a horse’s teeth, we are removing the sharp enamel ridges on the cheek edge of the upper or maxillary cheek teeth and the tongue edge of the lower or mandibular cheek teeth. With care and conservative removal of tooth material, we are not likely to expose a pulp horn in which deposition of dentin by odontoblasts has been progressing normally – a healthy tooth. However, if a tooth or part of a tooth is too high in relation to the surrounding teeth and is impeding the normal function of the mouth, removal of some of the excess height of the tooth is more likely to result in pulp exposure. A recent study examining the amount of dentin over the pulp horns found that some pulp horns were present 1.87 mm from the occlusal surface. This amount of tooth material can easily be taken off with any type of dental grinding instrument, manual or power-driven. Incisor teeth are also very vulnerable to exposure of the pulp horns. Unfortunately, the only way to determine the depth of a pulp horn below the occlusal surface clinically would be to have a computed tomography (CT) scan performed of the horse’s head, not a very practical diagnostic tool!
No treatments should be initiated without first completing a thorough oral examination to determine the need for treatments and what specific treatments should be performed. Many times, in the case of teeth that are abnormally high, treatments must be staged by removing small amounts of tooth material at 4 to 6 month intervals instead of removing the tooth material all at once and risking a pulp exposure. The pulp does not even have to be directly exposed to cause problems, grinding close to the pulp can also result in bacteria traversing tubules from the surface to the tooth and causing a pulp infection. Of more importance than the type of equipment used to perform dental treatments in the horse is the equine oral anatomy and physiology knowledge of the operator of that equipment. Bruce Whittle, DVM, Trenton, MO
- I have heard mixed opinions about whether to use manual or power tools on horses teeth. Can you elaborate on this? (View Answer)
All equine odontoplasty instruments have one purpose, the removal of tooth material. Although there are some differences, the use of manual versus power instruments does not really matter. What is more important is that equine dentistry is not undertaken as a “cookbook” procedure in which the desired endpoint in every case is the same. Each individual horse has his own “normal”. This can only be determined through a thorough oral examination. Based upon this oral examination, the clinician then determines if, what and how much tooth material should be removed to minimize pain and maximize the working efficiency of that horse’s mouth.
Power instruments for equine dentistry do have the disadvantage that they have the potential to create heat that can damage teeth and can generally remove tooth material faster. The heat production can be countered by continual water cooling of the instrument cutting surface or intermittent cooling of the teeth with water after a short grinding period of 15 to 20 seconds on an individual tooth. The ability to grind material more quickly can result in exposure of the pulp horns of the tooth if care is not used but can be an advantage in that it can decrease the time of the dental procedure. Power instruments often allow for more precise removal of tooth material whereas hand instruments generally have larger blades that do not allow grinding of individual enamel points. Additionally, hand floats were shown in a recent study to result in more damage to the tooth surface as examined under very high magnification with a scanning electron microscope. The clinical significance of this finding is not known.
Some dental grinding instruments, whether manual or power-driven, are better at working in some areas of the mouth than others. I have found that, while I predominantly use power instruments, I still use hand floats occasionally to address portions of teeth I cannot smooth adequately with the power instrument. Therefore, I have found it important to have a variety of instrumentation to be able to handle the diversity I find in the mouths of different horses. Bruce Whittle, DVM, Trenton, MO
- I recently heard of the concept of dentistry being done with the horse's head lowered near the ground being better to get correct angles and avoid TMJ problems. What are your thoughts on that? (View Answer)
You bring up a very important question. A horse in the wild spends most of its time grazing with its head in a downward position. In this position, the cheek teeth and incisors will be in their best alignment with each other and the teeth will wear as intended. It is important to examine the relationship of the upper and lower incisors with the head in this position. It is also important to note the change in the relationship that occurs when the head is elevated to the horizontal position. A horse that has an aligned bite in the head down position will often develop an apparent overbite (actually overjet) in the horizontal head position. This means the mandible (lower jaw) is able to move in relation to the maxilla (upper jaw) and this is a good thing. While it is important to examine the horse with its head down, it is not necessary to work on the horse’s teeth in this position. I would submit that more abnormalities of a horse’s teeth occur by feeding them from an elevated feeder than working on their teeth with their head elevated.
Although disease of the TMJ does occur, it is relatively uncommon. The temporomandibular joint (TMJ) is the articulation of the mandible with the maxilla. Fairly unique among the joints of the body, the TMJ contains a fibrocartilaginous disc between the bony surfaces. It is a very interesting joint in that it does more than just hinge, it also allows a movement called translation, which allows some movement of the mandible side-to-side. This is important because a horse chews side-to-side rather than up and down. Only the teeth on one side of the mouth contact each other at the same time. Thus, when the left cheek teeth are grinding together, the right TMJ is undergoing translation and vice versa. The inherent “sloppiness” of the joint allows the joint to perform its needed functions without the need for perfection.
The horse’s mouth has an exquisite design that allows proper functioning despite variations from what a lot of people consider normal. When working on a horse’s mouth, we should not be trying to make that mouth conform to some pre-conceived ideal. We should instead perform a thorough examination of the head and mouth to determine what that horse’s normal is. For example, a horse that has asymmetry of the bones of the head will have teeth that may appear abnormal but the dental apparatus of the horse may be functioning just fine. Attempting to level teeth or “correct angles” will result in making the mouth less functional. Appropriate dental treatments must take into account the findings from the thorough examination. The position of the head during the dental treatments should take into account the comfort and safety of both the patient and the clinician. Bruce Whittle, DVM, Trenton, MO
- Hello and thank you for this opportunity! My mare will have stretches of time when she leaves a puddle in her feed dish. It seems to happen randomly as it occurs before her teeth are done as well as right after! Any idea why? (View Answer)
From the limited information you gave, I am going to assume that you are talking about a puddle of saliva. In the central United States, where I live, we have an abundance of white clover in many of our pastures and hay fields. White clover, as well as other legume plants such as red clover and alfalfa, can be infected with a fungus called Rhizoctonia. The fungus thrives in conditions of higher heat and humidity and produces a toxin called slaframine. This toxin, which can be present either in pasture plants or in hay, causes the horse to salivate more than normal. This is usually the only clinical sign and is not dangerous to the horse as long as it has an adequate water supply. Removal of the horse from the pasture for a couple weeks or removal of the suspect hay will typically resolve the problem.
Horses are thought to produce from 20 to 80 liters (5 – 20 gallons) on a daily basis anyway! Most of this is swallowed and assists in the early digestion of feed materials they eat. The act of chewing stimulates the release of saliva from the salivary glands. With slaframine intoxication, they often salivate without reason. I hope this answers your question. Bruce Whittle, DVM, Trenton, MO
- How often should a 33-year-old and a 4-year-old horse (Arabians) have their teeth floated? Do wolf teeth have to be removed? (View Answer)
The short answer to your first question is, “it depends”. Floating teeth is a subset of equine dentistry that includes reduction of the sharp enamel points from the vestibular (cheek) aspect of the maxillary (upper) cheek teeth and from the lingual (tongue) aspect of the mandibular (lower) cheek teeth. These sharp enamel points can cause trauma to the cheeks and tongue so they are reduced to prevent further trauma and allow the soft tissues to heal. The development of the enamel points to the degree that they cause trauma depends upon the anatomic structure of the head and teeth of an individual horse, the age of the horse and to some extent, the housing and feeding conditions of the horse. Floating a horse’s teeth is not and should not be a “cookbook” procedure. It should be based upon a thorough oral examination to determine the need for any dental interventions. There are also other dental interventions that may need to be performed, beyond just floating the teeth, depending upon pathology that is detected upon the oral examination. If the teeth are just floated as a routine procedure and an oral examination is not performed, it is very common to miss pathology that can be causing pain to the horse.
We generally recommend a young horse should have an oral examination twice per year until it has erupted all of its permanent teeth in position, around 5 years of age. Once a horse has all of its permanent teeth in position, an annual oral examination should suffice unless they have a diagnosed problem that requires care more often. Horses over 20 to 25 years of age often benefit from oral examinations twice per year as they tend to develop periodontal disease and sharp enamel rims on their almost worn out teeth. In the first 5 years of life, a horse will typically erupt 24 deciduous (baby) teeth and 36 to 44 permanent teeth. Because of all of this activity during that period, there is a high chance of a tooth erupting abnormally. If this is detected and corrected early, often a good occlusion of the teeth can be attained.
Your horses are at ages that would benefit from twice annual oral examinations by your veterinarian. Floating the teeth or any other dental interventions should be performed only if warranted based upon the findings of those oral examinations. I do find, in my own practice, individual horses that need to have their teeth floated every 6 months and others that can be floated every 24 – 30 months, but the decision to float is always based upon a thorough oral examination.
Your second question will generate differing opinions. Not all wolf teeth should be considered automatically bad. In my own practice, I take into account the use of the horse in addition to the size, sharpness and positioning of the wolf tooth. If I believe the wolf tooth is causing or will cause trauma to the cheek or tongue when the horse is bitted due to any of these factors, I will recommend extraction. If a young horse is going to be trained, I will often err on the side of extracting the wolf tooth so we can eliminate this as a cause of training problems if they occur. If the horse will not be bitted, has no soft tissue trauma as a result of the wolf tooth or the wolf tooth is not in a position that will cause a problem, I will generally not recommend extraction. I do not extract every wolf tooth I see. Extraction of the wolf teeth is a surgical procedure. There is an artery that courses in the palate close to the wolf teeth that can be accidentally lacerated during extraction. Because this can be fatal to the horse, extraction of a wolf tooth is not a procedure without risk. I try to base my recommendation upon a good oral examination and evaluation of the factors I have listed. Thank you for these very pertinent questions. Bruce Whittle, DVM, Trenton, MO
- My 7-year-old gelding has a large lump on the side of his nose about half way up his head and his breath is horrid. Our local veterinarian said it is a crooked tooth so food gets lodged behind it and decays there. He said that it isn't hurting anything and fixing it would be expensive. I worry about the constant putrid smell and how the decay might affect him long-term. What are your thoughts on this? (View Answer)
This is a situation in which a very thorough oral examination is needed. Radiographs of the head to evaluate the teeth and supporting structures on that side are also likely warranted. It is not normal for feed material to lodge in an area of the mouth. Typically, in a situation like this, the rotting feed material changes the pH locally and promotes the growth of bacteria that lead to the development of periodontal disease. Periodontal disease, in turn, leads to a destruction of the periodontal ligament that is responsible for maintaining the tooth securely in the alveolus. In severe cases of periodontal disease, the infection can extend to the root of the tooth and cause infection of the tooth itself or can extend to the sinus above the tooth roots depending upon which tooth is involved. If the lump resolves when the food material in the cheek is cleaned out with water lavage, there may be some treatments that can be undertaken that might help prevent the feed packing. On the other hand, if the lump remains and is hard, it is more likely the sinus is involved and one or more teeth may need to be extracted. Extractions of cheek teeth in the horse can be very difficult due to lack of access and healing can be problematic if there is sinus involvement. Radiographs are a necessity in cases of this type. Sometimes, more advanced imaging such as computed tomography is necessary to make a diagnosis and formulate a treatment plan. This case would likely benefit from either a consultation with or referral to an equine veterinary dental specialist. Thank you for your question. I hope you can figure out what is wrong with your horse. Bruce Whittle, DVM, Trenton, MO
- A year ago an equine dentist found a red spot above my mare's incisors. He took x-rays but showed no resorption. This red spot comes and goes. Can it be something other than equine odontoclastic tooth resorption and hypercementosis (EORTH)? (View Answer)
Equine odontoclastic tooth resorption and hypercementosis (EOTRH) is a disease of horse’s teeth that was first described in 2006. It is thought to primarily affect horses greater than 15 years of age but it has been diagnosed in younger horses. Most commonly, EOTRH affects the incisors and canine teeth but recent reports describe affected premolars. The disease is characterized by resorption and/or hypercementosis of affected teeth. These processes are best seen on radiographs of the teeth and an individual tooth may have either or both types of pathology present. With resorption, the teeth appear to be dissolving whereas with hypercementosis, the roots of the teeth become enlarged and almost bulbar in appearance. Teeth that have resorption are typically very painful. Horses with diseased incisors have trouble grazing. At this time, extraction of affected teeth is the treatment of choice.
Another possibility, based on your description, which is more likely if your horse is younger, is a parulis. This is a term for a “pimple” associated with a draining sinus tract, usually associated with a tooth affected by a root infection. It is possible for the opening of the tract to heal over then reappear at a later time. If this is the case, radiographs should be repeated within six months. Sometimes, taking a few radiographs at oblique angles will show up pathology that is inapparent in a radiograph with standard positioning. Tooth root infections will usually progress to death to the tooth and are painful. When a tooth dies, the odontoblasts lining the pulp will quit producing dentin and on radiographs, the pulp of the diseased tooth will be wider than the pulp of the analogous tooth in which dentin production is continuing normally. This radiographic change does take some time to be apparent. Treatment options in these cases include either endodontic therapy (root canal) or extraction of the affected tooth. Both procedures have advantages and disadvantages and should be discussed on a case-by-case basis. While some clinicians will try a course of antibiotic therapy, this is almost never curative.
I would recommend a careful examination of the tooth with an explorer to search for any defects of the occlusal (chewing) surface of the tooth, with a periodontal probe to check the space around the tooth to check for periodontal disease and radiographs at standard and oblique angles to carefully evaluate the tooth root. Although your horse may not appear to be in pain, this can be difficult to determine because horses are prey species so it is ingrained in them not to show pain as a sign of weakness to predators. People that have had teeth with diseased pulps are certainly happier after they are treated! Unfortunately, we cannot ask our animals if they hurt. If nothing can be detected on careful exam and radiographs, evaluation at six-month intervals will allow for early detection if signs of root abscess become apparent. Thank you for your question. Good luck with your horse! Bruce Whittle, DVM, Trenton, MO
- My 20-year-old Thoroughbred mare has lost some weight since our move from hot California to a cooler Salt Lake City, Utah, two months ago. Her last dental floating was 2½ years ago because she is an incredibly spirited mare. She is scheduled for another dental examination soon. Could the weight loss be associated with the move or perhaps the need for dental care? (View Answer)
Weight loss in horses can have many different causes. The big three, which are the first we try to rule out as veterinarians, are nutrition problems, parasite issues and dental problems. I would recommend a thorough examination by your veterinarian, including a thorough oral examination. Dental problems including abnormal wear patterns and periodontal disease causing loose teeth are common in horses of this age and can certainly cause weight loss. Although your mare is spirited, we are lucky to live in a time of good sedative agents. Your veterinarian will tailor a sedation protocol with various sedative, tranquilizers and analgesics to provide an appropriate level of restraint while providing safety for both the patient and the clinician. Sedation is necessary for performance of a thorough oral examination anyway. Although I am not familiar with your past or present location, I would guess your horse has more parasite exposure now, especially if she has pasture access, which I assume was less likely in California. Your veterinarian will collect a deworming history and will likely collect a fecal sample for testing to assess whether parasites are a problem. If your horse had been on stored forages in California, she may not have developed much resistance to parasites. Evaluation of nutrition as a cause of weight loss often requires forage testing to make sure the nutrient content of the hay is adequate. Sometimes older horses benefit from a change in diet that includes a higher calorie content and is more easily digestible, such as a complete pelleted diet.
If the “big three” are ruled out as causes of the weight loss, the search gets harder. Diagnostic testing including complete blood counts, blood chemistry panel, and endocrine testing are likely the next step. These tests may point to liver, kidney, endocrine or muscle problems or may indicate inflammation somewhere in the body. Malabsorption syndromes can result in weight loss by reducing the absorption of nutrients in the gastrointestinal tract. Heart disease can also cause weight loss and may require cardiac ultrasound and an electrocardiogram (ECG) to diagnose. Although uncommon, certain types of cancer can also cause weight loss in the horse. You did not mention decreased appetite so that is likely not a part of the problem, but if it is, there could be a palatability issue with her new forage. Behavioral problems can also cause weight loss. Stress from being in a new location or a change in any buddies she is with can cause problems. If she is by herself, the addition of a buddy can sometimes help.
As you can see, weight loss in the horse can be due to a variety of reasons. A very thorough history can sometimes lead to a diagnosis of the problem or at least narrow down the myriad possibilities. It makes sense to address the “big three” first because these are the most common. Once these are ruled out, a systematic diagnostic approach will hopefully uncover the cause of your mare’s weight loss. Good luck! Bruce Whittle, DVM, Trenton, MO
- My mom has a 41-year-old retired pack/riding mule with neg. teeth and has to be fed 4x a day with soaked pellets. Do they have anything for older horses/mules like implants/ add-ons etc. Or is such a request too far off into the future? (View Answer)
There was a recent article published in the Journal of Veterinary Dentistry discussing dental implants in dogs. Unfortunately, for horses and mules, because of the way they chew in a side-to-side manner and the need for a lot of chewing surface with which to process their forages, dental implants in them would require some significant engineering. The shear forces acting on the teeth would require that potential equine dental implants have deep and robust anchoring in the jaws to support them. I don’t foresee dental implants for horses and mules being a possibility any time soon.
Thankfully, for our tooth deficient equid friends, there are some good complete diets on the market, as you alluded to, that allow them to live beyond the constraints of their teeth. I believe more work needs to be done to find the optimal fiber length and composition for these pelleted feeds because some older horses in this situation have problems with chronic watery manure due to water retention in the colon. Research into feeding senior horses and mules would be more practical than trying to develop artificial teeth for them. As we learn more about the teeth of horses we are also diagnosing periodontal disease and malocclusions earlier and determining better treatment methods. This may allow us to maintain the integrity of the chewing apparatus longer with appropriate dental care. Thank you for your question. Bruce Whittle, DVM, Trenton, MO