b'AAEPFORUM TheHorse.com/AAEP-ForumCAROLINE NIEDERMAN, VMD, FAVD EQUnderstanding Changes in Senior Horses Chewing Abilityorses teeth do not grow continually. H Rather, they erupt and wear over time. By the time a horse reaches his late teens and early 20s, normal age-related changes are occurring within the chewing surfaces of his cheek teeth that cause progressive loss of surface area. Owners need to make dietary changes for their older horses in light of this, and watch for common dental issues seen in this aging population. These series show how cheek teeth wear as horses age. From left to right, you can see how a The chewing and grinding surfaces ofyounger horses enamel folds (see arrows) wear down, starting in the center until enamel remains only along the tooths outside ridge. The result is a substantial collective loss of grinding ability.horses cheek teeth are rough, due to folds of very hard enamel. They also contain cementum and dentin that surround COURTESY DR. CAROLINE NIEDERMANand fill in the crevices within the enamel folds, respectively. Cementum and dentin are softer than enamel, so they are not useful for grinding feed, especially hay. As a horse ages and wears down his teeth, they get shorter and shorter and their rate of eruption slows. And as he enters his teens, and cer-tainly by the time he reaches his 20s,small enough size but tries to swallow itchewing hay but more slowly, so over the the rate of eruption has diminished toanyway. Another dangerous consequencecourse of a 24-hour period they are getting the point that new enamel is no longerof reduced grinding is the development offewer and fewer calories from the hay. surfacing to replace the existing enamel.an impaction within the horses gastroin- If the horse is either not consuming any So, these folds begin to wear. The centertestinal tract. When the teeth arent ablealternative feeds (senior feeds, hay substi-of each tooth becomes smooth, reduc- to do as much grinding, the horses smalltutes such as chopped hay or fiber pellets) ing the horses effective chewing surfaceand large intestines have to do more workor theyre being offered in insufficient area. The exposed dentin and cementumto make up for it. If they cant keep up,quantities to maintain body weight, he continue to wear, eventually causing thethe hay can build and cause an obstruc- will lose body condition. Adjusting the diet tooth to wear down to the gum line. Antion. These horses produce less manure,will reverse this loss, but it can take two outer rim of enamel sometimes remains. and the fecal balls they do produce will beto three months for horses to return to an The horses mouth works hardest whendrier than normal.ideal body condition score (a 5 out of 9).chewing hay, so all owners of seniorHorses with advanced wear dropWhen it comes to caring for senior horses should monitor: clumps of hay (called quidding) whilehorses, veterinarians should not only ad-1. How well their horse is eating hay, andeating, especially when its stemmy hay.dress the common problems seen in these 2. The quality and quantity of the horsesOwners should be able to recognize theseanimals but also educate owners about manure.easily. Some horses might not even at- their horses chewing capacity. Making di-Unfortunately, the first sign of inef- tempt to eat hay that they have figured outetary changes as horses lose their ability fective chewing is often a choke episodeis too coarse for them to grind. This leadsto grind long-stem hay will help prevent (esophageal obstruction) involving hay.to the sudden weight loss often seen inweight loss and other issues that can af-The horse cannot grind the hay to ahorses during their 20s. These horses arefect this age group. hAmerican Association of Equine Practitioners, 4033 Iron Works Parkway, Lexington, KY40511859/233-0147www.aaep.org14TheHorse.comTHE HORSE March 2018'