Influence of Age. 65 



(a) Heavy milk production is usually associated : 



1. With low body weight, 



2. With low measurement at the shoulder, 



3. With a straight back, although slight deviations should 

 not be considered as signs of small milk productiveness. 



4. With more or less prominent hips and rump according to 

 the characteristics of the breed. 



5. With the more pronounced depth of thorax ; heavy milkers 

 are often narrow and flat chested ; 



6. With long shoulders, 



7. With long rumps, 



8. With long, narrow head, 



9. Generally with fineness of horn, 



10. With fine bony structure ; 



11. The most important is the udder. The best cows have 

 large udders of spongy-granular consistence, with large tortuous 

 mammary veins, large milk wells, and easily movable skin. 



The skin should lay together over the perineal surface of the 

 udder in 4 to 6 or more large, well developed folds. The udder 

 should collapse thoroughly after milking, and the animals should be 

 easy milkers. Relatively early calving seems to have a good in- 

 fluence. The possibility of estimating the qualitative production 

 of milk from external conformations is only very slight. As a 

 rule, as shown by investigations, the smaller and shorter animals 

 with fine long bones produce milk of higher quantity, and above 

 all milk with a large yield of fat. 



The productiveness of one and the same individual varies, 

 especially with age and the lactation period. Cows with the first 

 calf, provided normal conditions prevail, do not produce as much 

 milk as after subsequent calvings ; as a rule when cows reach the 

 age of 7 to 9 years with the fifth and sixth calf, the maximum pro- 

 duction is obtained. With the advance of age the production 

 again gradually recedes. The proportion of solids is higher in 

 cows with the first calf than in those which have calved several 

 times; the quantity of fat on the other hand, as compared with 

 that of older cows, is smaller (Teichert, Hittcher, Hogstrom, Vieth 

 and others). 



The variations which are manifested in the production of milk 

 during single lactation periods are considerable, and depend en- 

 tirely upon the individual, as does the length of the milking period. 



For a few days after parturition a product is secreted which 

 has very little in common with milk, and which may be considered 

 as a product of glandular inflammation as a result of physiological 

 irritation. It corresponds strikingly in its appearance and com- 

 position, as well as in the microscopical appearance of its cream 

 and sediment with the inflammatory product of the milk gland. 



This product called colostrum is a yellowish or even yellowish-red, slimy fluid, 

 with an acid reaction. Corresponding to the increased content of albumen, globulin and 



