RAISING DAIRY CATTLE 441 



fat, which will persist when she is in milk. In these trials the heifers 

 which were heavily fed and became fat were possibly slightly inferior 

 in milk production to those receiving less concentrates, tho they lost their 

 excess fat within a short time after calving. Any effect of such over- 

 feeding while young is of little importance in determining the productive 

 capacity of a cow compared with her inherited qualities. The results 

 show, however, that feeding a heavy allowance of concentrates is a much 

 more expensive way of raising heifers than giving them a ration con- 

 sisting mostly of good roughage. 



705. Age to breed. The age at which heifers should drop their first 

 calves depends on the breed and the size and development of the indi- 

 vidual. Jerseys and Guernseys which have been well-fed should usually 

 be bred to calve at 24 to 28 months of age, while the slower maturing 

 Holsteins, Ayrshires, or Brown Swiss should not calve until 28 to 36 

 months old. Some breeders believe that if the heifer calves at an early 

 age, the tendency to milk production will be intensified, but data secured 

 by Eckles 51 indicate that the highest milk production is usually secured 

 from cows which are well matured before lactation begins. He found 

 that gestation had practically no effect upon the rate of growth of heifers. 

 However, the growth of an animal is checked materially both in skeleton 

 and live weight, as soon as lactation begins, owing to the large amount of 

 nutrients needed for the milk. Therefore, when heifers are fed scanty 

 rations and also bred to calve early, they will be stunted. As a rule, cows 

 that have dropped their first calves at an early age are finer in bone 

 than those which do not calve until more mature. 



706. Feed eaten by heifers; cost of rearing-. The feed required in 

 raising heifers and the cost of this and of other items of expense will 

 vary considerably, but from the following data one can closely estimate 

 the probable cost under his local conditions. The following table shows 

 the total amount of feed eaten by heifers during the first and second 

 years, as determined in various trials : 52 



Feed eaten ~by "heifers up to 2 years of age 



. . Wisconsin Ohio Ohio Illinois 



first year Jerseys Jerseys Holsteins Holsteina 



Whole milk, Ibs 342 465 499 244 



Skim milk, Ibs 3,165 2,928 2,786 860 



Concentrates, Ibs 547 597 656 1,107 



Hay or stover, Ibs 857 749 797 1,067 



Succulent feeds, Ibs 353 458 586 1.669 



Pasture, days 123 122 128 



Second year 



Skim milk 87 174 



Concentrates, Ibs 785 870 



Hay or other dry fodder, Ibs .' , 1,792 1,292 1.651 



Silage, Ibs 3,250 2,426 2,247 



Pasture, days 171 159 151 



61 Mo. Bui. 135. 



B2 Bennet and Cooper, U. S. Dept. Agr. Bui. 49; Hayden, Ohio Bui, 289; Hulce 

 and Nevens, 111. Cir. 202. 



