Presentation on theme: "Do you know my age??. Horses' teeth are often used to estimate the animal's age, hence the sayings "long in the tooth" and "Don't look a gift horse in."— Presentation transcript:
Do you know my age??
Horses' teeth are often used to estimate the animal's age, hence the sayings "long in the tooth" and "Don't look a gift horse in the mouth".
The Importance of Determining the Age of Horses Uses: Validate advertised age when buying Confirming age when racing or showing Feeding for proper nutrition at various life stages
Aging by Teeth Not foolproof An art that requires skill and experience Very old method of aging horses Error increases with horse’s age Becomes an educated guess after horse is older than 14 years Stabled horses tend to appear younger (less tooth wear) Pastured horses tend to appear older (more tooth wear) Bishoping- altering teeth to hide age
Equine Tooth Structure Horses have 24 temporary teeth and up to 42 permanent teeth Canines Incisors Wolf Tooth (when present) Mandible Premolars Molars Maxilla
Deciduous- ID3/3 CD0/0 PD3/3 MD0 Permanent-I 3/3 C 0-1/0-1 P 3-4/3 M3/3
How many teeth does a horse have? A typical adult male horse has 42 permanent teeth, while a typical mare may have 36 teeth, because mares are less likely to have canine (bridle) teeth. A horse’s permanent teeth are about four inches long.
Dentition Hypsodonts Two times Incisors 3/3 Canines 1/1 Premolars 3 or 4/3 Molars 3/3 Male total of 40 or 42; female total 36 to 40 Young horse has 24 deciduous teeth Milk teeth 12 incisors 12 molars
Do horses have “baby” teeth? Like humans, horses have two sets of teeth in their lifetimes. The baby teeth, called deciduous teeth, are temporary. The first deciduous incisors may erupt before the foal is born. The last deciduous teeth come in when the horse is about eight months of age. These “baby” teeth will begin to be replaced by adult teeth around the age of 2 ½, and by age 5-6, most horses have all of their permanent teeth.
Estimating age using tooth eruption There are 24 deciduous teeth (“caps”). These come out in pairs, and are pushed out later by the permanent teeth. The “caps” are usually present at birth or by 1 to 2 weeks of age. Rule of 3 eights: I1- 8 days, I2- 8 weeks, and I3- 8 months -charts may show these as Di1, Di2, Di3 The number of permanent teeth may vary, depending on if the horse has wolf teeth or canines.
Aging - Incisors Deciduous eruption pattern: 6-8 days 6-8 weeks 6-8 months Premolar eruption pattern: PM 2 years 8 months PM 2 years 10 months PM 3 years 8 months Permanent eruption pattern: 2.5 years 3.5 years 4.5 years Molar eruption pattern: 1 year 2 years years
Cups, stars and spots: The cup is the center of the infundibulum. Wear of the occlusal surface causes the cup to get smaller and eventually disappear from all lower incisors at about 6-8 years of age leaving the enamel spot in its place. The enamel spot is the deepest part of the infundibulum. The dental star corresponds with the pulp cavity and appears at 8 years of age in the first incisor. It appears as a line and then changes to a large, round spot as the occlusal surface is worn further.
The anatomic relationships between incisor anatomy and the cups and stars seen on the occlusal surface as they wear are depicted in the images and diagrams immediately above. The image on the right is shows an incisor of a young horse cut longitudinally while still in the jaw.
Equine Tooth Structure Age is determined using the 12 front teeth (incisors) Central Incisors (also pincers or nippers) Intermediate Incisors Corner Incisors
Mouthing a Horse for Age In Real Life: Hold the tongue out and to the side with your hand. This restraint provides an unobstructed view and is not painful to the horse.
Tooth Emergence Permanent Teeth 6 years old Canine teeth appear: 4-5 years Permanent corners: 4 ½ years Permanent intermediates: 3 ½ years Permanent pincers: 2 ½ years
Tooth Wear As horses age, “caps” disappear from incisors As horses age, teeth become more triangular-shaped 15 years old 6 years old
What are wolf teeth? Wolf teeth are the remnants of the first premolars that have now become obsolete with the evolution of the horse. The most common first premolars seen in the horse are the uppers and they are shaped similar to small canine teeth. This is why they are often described as wolf teeth. These sharp teeth, if present, are in the area of the mouth where the bit fits. Wolf teeth may cause the horse some discomfort when pressure is placed on the bit. Therefore, these teeth are usually removed in young riding horses.
Wolf tooth A typically small maxillary wolf tooth (premolar [PM] 1) is present just rostral to PM2.
First premolar (PM1): Wolf tooth 6 months Deciduous premolars: Present at birth. Shedding teeth or caps.
Galvayne’s Groove A mark on the upper corner incisors that appears and disappears in a predictable pattern as horses age Usually appears around the age of 10 years.
Galvayne’s Groove A mark on the upper corner incisors that appears and disappears in a predictable pattern as horses age Groove is usually half way down at age 15
Galvayne’s Groove A mark on the upper corner incisors that appears and disappears in a predictable pattern as horses age By age 20 the groove usually extends the full length of the tooth
Galvayne’s Groove A mark on the upper corner incisors that appears and disappears in a predictable pattern as horses age Groove begins to recede around age 21
Galvayne’s Groove A mark on the upper corner incisors that appears and disappears in a predictable pattern as horses age Groove is halfway gone by age 25 and disappears completely around age 30.
7 year notch Length with age Disappears at 8 years, returns at 11 “long in the tooth”
I1I2I3 Baby erupt8 days8 weeks8 months Permanents erupt2 1/23 1/24 ½ Cups gone6 years7 years8 years Dental Star8years9 years10 years Galvayne’s groove years Seven year notch7years, and 11 years Shape of teeth Round 9-11 years Triangular years Biangular years
Aging Using Teeth Determine the most likely age for the following horse 1.7 years 2.14 years 3.21 years 4.28 years Wear – No Cups
Aging Using Teeth Determine the most likely age for the following horse 1.1 year 2.8 years 3.17 years 4.26 years Oval Shaped Teeth No Canines
Aging Using Teeth Which horse is older? A B
Common ages for tooth eruption ( page 248 LACP ) Type of toothNumberDeciduousPermanent IncisorFirst (central)birth to 8 days2.5 yrs IncisorSecond (intermediate)4.5-6 weeks3.5-4 yrs IncisorThird (corner)6-9 months4.5-5 yrs CanineAbsent3.5-5 yrs, some around 6 yrs (if ever) PremolarFirst (wolf)Absent6 months to 3 years (if ever) PremolarSecondbirth to 2 weeks2-3 yrs PremolarThirdbirth to 2 weeks2.5-3 yrs PremolarFourthbirth to 2 weeks3-4 yrs MolarFirstAbsent9-12 months MolarSecondAbsent2 yrs MolarThirdAbsent3-4 yrs
How do diet, pasture management and stabling impact dental wear? Mother Nature designed horses to be pasture grazing animals. Horses in the wild normally spend 16 hours a day with their heads down, grazing grass. For a horse to properly process pounds of wet-grass forage a day, it uses a wide, crushing chewing pattern. This allows the incisor teeth and cheek teeth to wear at a normal and even rate. Under artificial conditions, horses are fed an abnormal diet (grain and hay) for shorter intervals during the day, with an abnormal head posture (feed tub or hay rack). All of these conditions alter the chewing pattern and adversely affect the way teeth are worn over time.
What is cribbing and how does it affect dental care? Cribbing is a stereotypic behavior, or vice, that some horses develop. The horse exhibits cribbing by grabbing onto an inanimate object (fence posts, buckets, stall walls, etc.) with its incisor teeth, pulling the object and often making a sucking sound. Because these horses spend the majority of their time during the day preoccupied with this behavior rather than grazing or eating, they quite often have dental wear problems. The upper incisor teeth (front teeth) are often worn excessively from hours of abnormal attrition. These horses are referred to as "stump suckers.”
What does it mean to “float” a horse’s teeth? Routine maintenance of a horse’s mouth has been historically referred to as “floating.” Floating removes the sharp enamel points. Occlusal equilibration is the term now used to describe smoothing enamel points, correcting malocclusion (faulty meeting of the upper and lower teeth), balancing the dental arcades and correcting other dental problems.
Triadan Numbering System 100’s = Right maxilla 200’s = Left maxilla 300’s = Left mandible 400’s = Right mandible Incisors = 1,2,3 Canines = 4 Wolf teeth = 5 Premolars = 6, 7, 8 Molars = 9, 10, 11
Upper R Cheek Upper incisors Upper L Cheek Lower R Cheek Lower Incisors Lower L Cheek
Dental Examination Visually inspect: Prior to rinsing mouth After rinsing mouth Digitally palpate: Individual teeth Gingiva Palate Tongue Record findings on a standard form
Historical Clues to Dental Problems Performance habits Head tilt Head tossing Refusing the bit Eating habits Quidding Slow, deliberate mastication Exaggerated tongue movement
Change in fecal character Increase in fiber length Whole grain in feces Weight loss Poor body condition Facial asymmetry Unilateral nasal discharge Halitosis
Dental Examination: Juvenile Age: 6 months to 7 years Incisors Check occlusion Inspect eruption pattern Canines erupting at this age. Premolars: Look for wolf tooth. Inspect for caps. Periodontal disease Molars Inspect eruption pattern. Exam frequency: semiannual
Age: years Incisors Inspect for Injury or damage Supernumerary teeth Missing incisors Misalignment Wear pattern
Age: 7 – 15 years Canine teeth Check for sharp points Check for tartar
Age: 7 – 15 years Premolar and molar teeth: Enamel points (odontophytes) Occlusion abnormalities Hooks and ramps Unopposed teeth Wave/Shear mouth Exam frequency - Annually
Dental Examination: Geriatric Age: 15 years and older Premolar and molar teeth: Periodontal disease o Most common condition affecting horse > 15 years of age o Gingival recession o Diastema formation Molar cupping Wearing of infundibular enamel Dental caries Tooth root abscess Tooth loss Exam Frequency - Semiannual