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Wednesday, 29 October 2008 16:41

Teeth and Teeth Problems

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Ruminants
  • Cattle, goats, sheep and other ruminants have no upper incisors - they have a hard dental pad and their bottom incisors (eight of them) bite against that.
  • The temporary incisors of the very young animal are gradually replaced by permanent incisors in pairs, starting with the central pair, then working outwards.
  • Here are the approximate ages of eruption of the permanent incisors in cattle, sheep and goats.
  • Bear in mind that there is a lot of variation between individual animals.
Cattle:
  • Centrals 1½ - 2 years
  • second incisors 2 - 2½ years
  • third incisors 3 years
  • fourth incisors 3½ - 4 years
 Sheep and goats:
  • Centrals 1-1½ years
  • second incisors 1½ - 2 years
  • third incisors 2½ - 3 years
  • fourth incisors (full mouth) 3 to 4 years
  •  Until it is about 4 years old, the animal’s age can be determined by the number of permanent incisors it has.
  • After 4 years of age, age can be difficult to assess because of tooth wear and lost teeth.
Horses
  • Horses have six incisors on both the upper and lower jaws.
  • The central pair of permanent incisors erupt at about 2½ years of age,
  • the second pair erupt at 3½ years,
  • the fourth pair at 4½ years.
  • As with ruminants, the age of the young horse can be determined by the number of permanent incisors it has.
  • After 5 years of age, other features of the incisors can be used to help assess age.
  • These features include the pattern of enamel and dentine on the biting surface, the presence of enamel spurs on the outer edges of the third upper incisors, and the angle of the incisors in the jaw. But it takes an expert to do this accurately!
Teeth and jaw problems
 
Excessive incisor wear
  • With excessive wear, the incisors become short and may be worn down to the level of the gums. This happens when soil or sand on pasture gradually files away at the teeth until they are worn, so it is usually only a problem in older animals.
  • Livestock with very worn incisors can do well as long as they don’t have to eat very short or stringy pasture. They can be fed long soft pasture or hay or silage or concentrate feed.
Periodontal disease
  • In any animal, periodontal disease of the incisors causes them to become long and loose and they may be missing. This is caused by infection around the teeth (periodontitis).
  • If an animal has only a few very loose incisors, they are probably best removed, either with your fingers or with pliers.
  • The animal will then be ‘gummy’, but it can still stay in good body condition if it is offered long soft pasture or hay or silage or concentrate feed.
  • Don’t attempt to remove any teeth that are not already very loose.
Problems with cheek teeth
  • Cheek teeth may become unevenly worn, so they don’t grind feed efficiently and can cause ulcers on the cheeks and tongue.
  • The signs of this include dropping of feed from the mouth while chewing, bulging of the cheeks caused by wads of food becoming impacted between the teeth and cheek, and/or green staining around the mouth caused by drooling of saliva.
  • Overgrown edges on cheek teeth are common in elderly ponies and horses.
  • Treatment is by rasping the sharp edges and it takes a trained person like a veterinarian or a horse dentist to do this effectively.
  • To prevent problems, it is wise to have the cheek teeth of ponies and horses rasped regularly, perhaps once a year or so, by a veterinarian or a horse dentist.
  • Periodontal disease can affect cheek teeth as well as incisors. It is caused by infections of the gum and supporting structures around the cheek teeth roots.
  • In severe cases the bone becomes swollen and sore, then the animal is reluctant to chew its cud and it gets thin.
  • If you suspect any problems like this, consult your veterinarian.
Overshot and undershot jaws
  • Sometimes animals are born with a lower jaw that is too short (ie it meets the top pad well behind its front edge, called undershot or “parrot mouth”).
  • Sometimes the lower jaw is too long (ie it protrudes, called overshot).
  • Depending on the severity of the abnormality, the animal may or may not be able to suckle or graze.
  • If the problem is not too bad, affected calves and lambs can be fattened for slaughter if they are grazed on good quality long pasture.
  • Don’t breed from animals with under- or overshot jaws, as these problems can be hereditary.
  • Don’t try to be a dentist!
  • Problems with teeth can cause a lot of pain, and they can make eating very difficult.
  • You mustn’t allow animals with painful mouths to suffer and you mustn’t cause unnecessary pain and suffering if you try to treat them yourself.
  • Consult an expert such as a veterinarian if any of your animals has any significant problems with its teeth. 
Dr Marjorie Orr, lifestyle farmer and veterinarian (retired)

Dr Marjorie Orr - veterinarian and lifestyle farmer. Dr Orr is a recognised authority on animal welfare in New Zealand and has served on several government committees, especially those concerned with writing codes of welfare for sheep and dogs. Her service to animal health and welfare has also been recognised by awards from the NZ Veterinary Association and MAF. She is also a strong SPCA supporter.

Website: www.lifestyleblock.co.nz/images/imgDrMarjorieOrr.jpg