18 



FARMER'S CYCLOPEDIA OF LIVE STOCK 



pulse rate. From each segment of the 

 spinal cord a pair of spinal nerves arises, 

 each of which possesses both sensory and 

 motor roots. The sympathetic nervous 

 system consists of a trunk on either 

 side running from the base of the skull 

 to the pelvis, furnished with ganglionic 

 enlargements and connected with the 

 spinal nerves by small fibers. 



The teeth show great differences in 

 form and arrangement in different 

 farm animals. The typical full denti- 

 tion includes incisors in front, followed 

 by an eyetooth or canine, premolars and 

 molars or grinders. Each tooth con- 

 sists of a root, neck and crown. Nerves 

 and blood vessels enter the tooth through 



below. The dog has, when enumerated 

 in the same manner, three incisors, one 

 canine, six molars above and seven mo- 

 lars below, while in the cat the dentition 

 is tbe same except that there are four 

 molars above and three below. 



Colts' teeth — Colts are born with 

 the first two incisor teeth; the middle 

 incisors appear after four to six weeks 

 and the corners after six to nine months. 

 The central incisors are shed at the age 

 of 2 1 /2 to 3 years, the middle incisors at 

 8^2 to 4 years and the corners at 4V& to 

 5 years. The horse thus has a full set 

 of permanent teeth at five years of age. 

 As a rule cattle keep their milk incisors 

 till the age of 18 months while the 



Fig. 11 REPRESENTATIVE OF THE WILD CATTLE OF ENGLAND. A DESCEXDAN 



OF THE AUROCHS 



the root and terminate in the tooth cav- 

 ity. The tooth substance consists of a 

 dentine base covered with a hard enamel. 

 Considerable growth takes place in the 

 tooth to offset the loss from wear. 



Horses'' teeth — Normally the horse 

 has forty teeth or on either side of each 

 jaw three incisors, one canine, and six 

 molars. Occasionally a so-called wolf 

 tooth is present, which is a premolar 

 tooth. In cattle, sheep and goats there 

 are no incisors in the upper jaw, while 

 there are four on either side below, no 

 canines in either jaw and six molars on 

 either side of either jaw. The hog has 

 three incisors, one canine, one premolar 

 and six molars on each side, above and 



permanent incisors are all in place in 

 the lower jaw at the age of five years. 



Lambs' teeth — Lambs are born with 

 the central incisors and the other milk 

 incisors appear within four weeks. The 

 shedding of the incisors begins at the 

 age of 12 to 18 months and is finished 

 at the age of four years. The pig is 

 born with the third incisors and the 

 others appear within three months. 

 The permanent incisors are in place at 

 the age of 18 months. 



The essential parts of the alimentary 

 canal f farm animals are mouth, 

 pharynx, oesophagus or gullet, stomach 

 and intestines with connected glands 



