378 Feeds and Feeding. 



priced land. When land is cheap and feed abundant the meat- 

 producing animals predominate, but when the land becomes higher 

 in value and feed expensive, the farmer turns to the dairy cow." 



592. Disposition of food. Jordan 1 holds that a typical dairy 

 cow, weighing 870 Ibs., when eating 15.5 Ibs. of digestible matter 

 daily and yielding 20 Ibs. of milk, disposes of her food daily as fol- 

 lows : 



Energy required to maintain" the body___ 13 therms 43.3 per ct. 

 Energy expended in '.manufacture of milk 9 therms 30. per ct. 

 Energy in 20 Ibs. of milk 8 therms 26.7 per ct. 



Total energy in 15.5 Ibs. digestible 



matter 30 therms 100.0 per ct. 



It is shown that a well nourished dairy cow uses about 43 per ct. 

 of the food she consumes to support her body, 30 per ct. in the work 

 of converting food into milk, and that nearly 27 per ct. finally ap- 

 pears as milk. This shows the cow to be a more efficient machine 

 than either the horse or the steam engine. (112, 817) 



593. Dairy v. beef type. The following from Smith 2 concisely 

 covers a vital point for the advanced dairyman : ' l Unlike the beef 

 animal, which is its own storehouse, placing its product within its 

 carcass, the dairy cow gives up each day that which she produces. 

 She has been developed along lines quite opposite from those of the 

 beef animal. In her development, performance, as indicated by the 

 quality and quantity of milk given, has been the chief guide in mak- 

 ing selections. The most perfect beef cows are not economical milk- 

 ers, and the best dairy cows are not satisfactory beef makers. The 

 two functions are quite different, making it impossible to develop 

 both to the highest degree in one animal." (686) 



594. Fat globules. Collier of the New York (Geneva) Station 3 

 placed the average secretion of milk by the cows of the station herd 

 at 0.7 lb., or 19.6 cubic inches per hour. He found that the one- 

 thousandth part of a cubic millimeter of average milk contained 152 

 fat globules, and accordingly that the average station cow secreted 

 138,210,000 fat globules each second thruout the day of 24 hours 

 w r hile giving milk. Babcock 4 tells us that a quart of average milk 

 contains not less than 2,000,000,000,000 fat globules. These figures 

 are beyond comprehension and should intensify our interest in the 

 marvelous processes of life. They lead us to ponder on the infinite 

 division which food must undergo during digestion. 



1 Eural New Yorker, Sept. 9, 1899. 3 Ept. 1892. 



2 Profitable Stock Feeding, p. 38. 4 Wis. Expt. Sta v Bui. 18. 



