GENERAL PROBLEMS IN DAIRY HUSBANDRY 341 



what little tendency they did have for milk production. Scrubs which 

 came to the station as heifers produced on the average 27 per ct. more 

 milk than those that were mature when they first received good feed and 

 care. The scrubs which were 4 years old when purchased showed less 

 response to good feeding than the heifers. These facts emphasize the 

 necessity of feeding heifers so that they will develop properly. 



In these trials the offspring from one of the pure-bred sires used on 

 the scrub cows fell much below the others in productivity. This illus- 

 trates the well-known fact that to build up a herd a sire must not only 

 be a pure-bred but also must be prepotent in transmitting dairy qualities 

 and high production. 



544. Causes of inefficiency of dairy cows. Observing a striking differ- 

 ence in the productive capacity of 2 Jersey cows at the Missouri Station, 

 which were raised under the same conditions and were more than half 

 sisters, Eckles and Reed 8 conducted the following trial to find the ex- 

 planation. During their first 2 lactation periods the better cow had 

 produced 2.8 Ibs. of milk and 3.9 Ibs. of fat for each pound produced by 

 the other. In the third lactation period the cows calved three days apart 

 and were fed the same feeds supplied in the same proportions, the 

 amount fed being so adjusted that neither cow gained or lost in weight. 

 Neither cow was bred. During the year the better cow consumed 1.75 Ibs. 

 of feed for each pound eaten by the other, but produced 2.67 Ibs. of 

 milk and 2.77 Ibs. fat for each pound yielded by the poorer cow. 



"When dry, the better cow required more feed to maintain her weight 

 than the poor one. Her greater efficiency was therefore not due to a 

 lower requirement for maintenance. She digested a slightly larger per- 

 centage of her ration, but there was far too little difference to explain 

 her much greater economy in production. The real cause of the greater 

 emciency of the better cow was that she was able to consume and utilize 

 a much larger amount of feed beyond the amount needed to maintain 

 her body, and hence had more feed available for milk production. 

 There was practically no difference in the amount of milk or fat pro- 

 duced by the cows from each 100 Ibs. of feed which they ate in addition 

 to the maintenance requirement. 



The high producing cow secretes an abundance of milk, on account 

 of her strong inherited impulse to milk production. To replace the 

 nutrients she puts into her product she has a keen appetite and con- 

 sumes much feed. 



545. Weed out unprofitable cows. Even in the leading dairy states, 

 probably one-fourth or more of the dairy cows fail to pay for their 

 care and feed. The chief reason why such a condition is found now, 

 when the principles of successful selection, feeding, and care of dairy 

 cattle have long been established by scientists and practical dairymen, 

 is that the owners do not know which of their cows fail to yield enough 

 milk to pay for their feed and care. They do not realize that tho the 



8 Mo. Research Bui. 2. 



