April 7, 2014 by vetintrainin

Carnivorous and Deciduous

Concerning Cat mouths

Cat, with its mouth open (Photo credit: Wikipedia)

Now we will look at a carnivore’s mouth, the cat mouth. Cats are “diphyodont”, which means they have two sets of teeth, the deciduous teeth shed and are replaced by the second, permanent set. Kittens are born with no teeth. At about 3 to 4 weeks of age, the deciduous teeth begin to erupt. By 6 weeks of age, all 26 deciduous teeth are present. At 4 to 5 months of age, the deciduous teeth are lost and the permanent teeth erupt. By six months, all of the adult teeth will have erupted. Adult cats have four types of teeth. The incisors, canines, premolars, and molars. In the upper jaw (the maxilla), there are 6 little incisors, two canines, three premolars, and one molar. The incisors are used mainly for picking up objects and for grooming. The canines are used for holding prey, and for slashing and tearing when fighting. Premolars function mainly for breaking food into small pieces, as well as for carrying and holding. The molars have flat surfaces and are used to grind food into small pieces. In the lower jaw (the mandible) you’ll find the same number of incisors, canines and molars, however, there are only two premolars instead of three. The total number of permanent teeth in a cat is 30. Ultimately, cat’s mouths are perfect for the carnivorous little felines.

To see more cat anatomy, click here to watch my video.

March 28, 2014 by vetintrainin

Cows and Configurations

English: Dental pad of domestic livestock. Note the lack of upper incisors and canine teeth. (Photo credit: Wikipedia)

Cow Mouths

This week we’ll be looking at cow mouths. Cows have 32 teeth. They have 6 incisors and 2 canines on the bottom. The canines are not pointed, but look like incisors. Also, there are no incisors on the top; instead cattle have a dental pad. Cows have 6 premolars and 6 molars on both top and bottom jaws for a total of 24 molars. In addition, there is a large gap between the incisors and molars. This configuration allows cattle to harvest and masticate large amounts of fibrous feed. Because their teeth are primarily for grinding, cattle use their tongues to grasp or gather grass and then pinch it off between their incisors and dental pad. Since they lack upper incisors, cattle cannot bite off grass very well, and they are inefficient at grazing closely. The inside of the cheeks and palate are rough which helps hold feed in while cattle chew with a side to side motion. In addition to reducing the size of feed particles, the mouth aids in digestion by adding saliva to the feed. Cows will produce 20-35 gallons of saliva a day. The saliva helps moisten the feed. Saliva also contains sodium bicarbonate to keep the rumen at the proper neutral pH (6.5-7.2) for good microbial growth. Much of the water contained in saliva is then recycled by the cow. In conclusion, compared to horses or humans, cows do not have the best mouth configuration. But, it does serve them well.

To watch my video, click here.

March 21, 2014 by vetintrainin

Essentially Complete

Horse Mouths.

Horse mouth (royalty free)

For the next few weeks, I’ll be writing about different animal mouths. Starting with the horse mouth. Horses grasp food using a combination of the lips, tongue, and teeth. Horses’ lips are extremely tactile when it comes to consuming feed. Feeds are mixed with saliva in the mouth to make a moist bolus that can be easily swallowed. There are three pairs of glands that produce saliva – the parotid, the submaxillary, and the sublingual. Horse saliva contains bicarbonate, which buffers and protects amino acids in their highly acidic stomach. Saliva also contains small amounts of amylase which assist with carbohydrate digestion. The mouth contains 36 – 40 teeth. Wolf teeth are not included as not all horses have them. The horse’s upper jaw is wider than the bottom jaw to allow for a chewing motion that is quite complex. The chewing action of the horse is a sweeping action which incorporates both lateral, forward, backwards, and vertical motions. This allows the feed to be effectively ground and mixed with saliva to initiate the digestive process. The texture of the feeds will dramatically influence the chewing rate (jaw sweeps) and rate of ingestion. An average horse will generally take 60,000 jaw sweeps per day when grazing. This amount will be dramatically reduced when confined to a stable and large amounts of grain are fed. When horses chew fibrous feeds such as hay or pasture it is a long jaw sweep action. This is why horses continually out on pasture rarely develop sharp edges on their teeth. Grains are consumed in a shorter sweep which does not extend past the outer edge of the teeth. When large amounts of grain are given, horses chewing action will be changed and the teeth will not be worn evenly. Hooks or sharp edges will start to form on the outside edge of the teeth. Conclusively, mouths are essential for digestion and a discussion about the digestive system would not be complete without them.