90 Oattle Problems. 



and more in a moderately thick slcin tlian in a tliin one. 

 Hence in any given degree of cold, with equal exercise, 

 thick-skinned cattle suffer least, because they have the 

 largest supply of sensible heat in the skin ; and cattle 

 having a moderately thick skin suffer less, because they 

 have more blood and heat in the skin than thin-skinned 

 cattle, which are the most tender of all, because they have 

 the least substance, and the smallest extent of heat liberated 

 in the skin. Thus it appears that thin-skinned cattle are 

 most liable to be tender, or to suffer when exposed to 

 cold. Tenderness in cattle, or other stock, consists mainly 

 in their inability to bear exposure to cold. Cattle of any 

 kind become chilled sooner by evaporation of their skin 

 heat, according to the coldness of the air, and the too 

 small quantity of heat set free in the skin. When they 

 are thin in flesh, and require warmth, less heat is set free 

 in the muscles, because the extent of their substance is re- 

 duced. The substance of the muscles is increased or 

 diminished according to action or inactivity in body, breath- 

 ing, and blood supply, during considerable lengths of time. 

 When exercise, breathing, and blood supply are full, the 

 muscles and the substance of the skin are well supplied 

 with heat, and cattle do not set their backs up, as they do 

 when suffering from cold. Chilling and shivering are in- 

 dications of tenderness, and result from the escape of 

 heat from the skin into the cooler external air. The arch- 

 ing up of the back retards the escape of heat in some de- 

 gree, by partly closing the pores in portions of the skin 

 where strained more than usual by this process. But the 

 setting up of the back is an evidence of tenderness, and 

 that the animal heat of the skin is escaping by evaporation 

 faster than it is supplied by nutritive changes in the sub- 

 stance of the skin. 



A thick coat of fine hair, which also indicates vigor, is 

 a great protection against evaporation and loss of heat ; 



