254 DISEASES OF CATTLE. 



theory having been largely taught, it becomes needful to thus sustain 

 the old and well-founded belief of the dairymen. 



Not only does the richness of the milk vary with the nature of the 

 food, but it varies also according to the time of the day when it is 

 drawn, the morning milk giving 1\ per cent of cream and the evening 

 milk 9-£ per cent (Hassall). Boedecker found that the morning milk 

 had 10 per cent of solids, while the evening milk had 13 per cent. 

 Again, the milk first drawn at any milking is always poorer than the 

 last drawn. The first may have only one-half, or in extreme cases 

 one-fourth, the cream of the last. Once more, when the cow is in heat 

 the milk becomes richer in solids (casein and butter), and contains 

 granular and white blood cells like the colostrum, andpften disagrees 

 with the young animal living on it. Now, while these various modifi- 

 cations in the amount of solid matters may prove harmless to a strong 

 and vigorous calf, they can easily be the occasion of intestinal dis- 

 order in a weaker one, or in one with health already somewhat 

 impaired by sickness, exposure, or unwholesome buildings. The 

 casein of the cow's milk coagulates in one solid mass, and is much less 

 easily penetrated by the digesting fluids than the fine flaky coagula of 

 woman's or mare's milk. An excess of casein, therefore, thrown on 

 an already overtaxed stomach can all the more readily induce dis- 

 order. So with butter fat. While a most important element in nutri- 

 tion, it may be present in the stomach in such amount as to interfere 

 with the action of the gastric juice on the casein, and with the inter- 

 ruption of the natural stomach digestion the fats themselves undergo 

 decomposition with the production of offensive and irritating fatty 

 acids. 



The milk of the very young cow is usually more watery than that of 

 the mature animal, and that of the old cow has a greater liability to 

 become acid. It varies much with the breed, the Channel Island cattle 

 being notorious for the relatively large amount of cream, while the 

 Holsteins, Ayrshires, and Shorthorns are remarkable rather for the 

 amount of casein. The milk of cows fed on potatoes and grass is very 

 poor and watery ; that from cows fed on cabbage or Swedish turnips 

 has a disagreeable taste and odor (from the former an offensive liquid 

 has been distilled). 



Cows fed on overkept, fermented, and soured rations have acid 

 milk which readily turns and coagulates. Thus old, long-kept brew- 

 er's grains, swill, the refuse of glucose factories, and ensilage which 

 has been put up too green, all act in this way. The same may come 

 from disease in the cow's udder, or any general disease of the cow with 

 attendant fever, and in all such cases the tendency is to rapid change 

 and unwholesomeness. If the milk is drawn and fed from a pail there 

 is the added danger of all sorts of poisonous ferments getting into it 

 and multiplying; it may be from the imperfect cleansing and scalding 

 of the pail ; from rinsing the pails with water that is impure ; from the 



