DETERMINATION OF AGE BY THE HORNS. 173 



prolongation of the skin, similar to the covering of the hoof of 

 the foal at birth, but by the twelfth to fifteenth month this 

 covering has dried and scaled off, leaving the natural, shhiing, 

 tough surface of the horn proper. 



In the second year the horns start a fresh growth, and a 

 small groove is found encircling it between the substance secreted 

 the first year and that wliich developed in the second. 



During the third year a similar activity in growth takes 

 placed and a second groove is found marking the line between 

 the two years' growth. These two grooves or circular furrows 

 around the horn are not well marked and have been frequently 

 overlooked, and all trace of them disappears as the animal be- 

 comes older. 



From three years on, the growth of the honi is marked by 

 a groove or furrow, much deeper and so distinct that they show 

 between them a decided elevation or " ring " of horny substance, 

 which forms an accurate basis for estimating the age of the 

 animal. In an animal over three years of age we count all of the 

 horn beyond the first groove as indicating three years, and add 

 one year to its age for each groove and " ring " which is present 

 toward the base of the horn. 



The grooves are always better marked in the concavity of 

 the horn than on the convex surface. In feeble, ill-nourished 

 animals they are but slightly marked. 



Many causes, however, tend to diminish the value of the 

 ^' rings " and grooves in the estimation of age. In " show " 

 cattle and in herds of cattle kept for show, the horns are fre- 

 quently sand-papered, scmped, and polished to give them the 

 iine appearance of delicate texture, which, with that of the other 

 integument, indicates the similar condition of the mammary 

 gland for secreting milk and of the connective tissue for forming 

 fat. Dealers scrape the horns to destroy the evidences of age 

 in the animals which they have for sale. In old cows there is 

 an atrophy of growth and an apparent contraction of the base 

 of the horn ; the rings and grooves are much less distinctly 

 marked and may be indistinguishable. 



