GROWTH AND FATTENING 79 



i. e., rich in protein and mineral matter. For this reason, such feeds as 

 hay from clover, alfalfa, or other legumes, and protein-rich concentrates, 

 as wheat bran and linseed meal, are of high value for young animals. 



The second part of the table shows that colostrum, which is the first 

 milk yielded by the mother for her young, is much richer in protein and 

 often higher in ash than normal milk. The high protein content of 

 colostrum is largely due to its excess of albumin, which causes such milk 

 to clot on heating. Colostrum is laxative and highly important for cleans- 

 ing the alimentary tract of accumulated fecal matter and properly 

 starting the work of digestion. During the week following birth the com- 

 position of the milk gradually changes to normal. 



116. Relation between composition of milk and rate of growth. In their 

 analyses of different kinds of milk Bunge, Proeseher, and Abderhalden 9 

 noted the striking relationship, shown in the table, between the rate at 

 which different species of animals grow and the amount of mineral matter 

 and protein contained in the milk : 



Influence on growth of amount of protein and mineral matter in milk 



Time required Protein Lime Phosphoric Total ash 



Species to double weight in milk in milk acid in milk in milk 



Days Per ct. Per ct. Per ct. Per ct. 



Human 180 1.6 0.03 0.05 0.20 



Horse 60 2.0 0.12 0.13 0.40 



Cow 47 3.5 0.16 0.20 0.70 



Sheep 15 4.9 0.25 0.29 0.84 



Pig 14* 5.2 0.25 0.31 0.80 



Dog 9 7.4 0.45 0.51 1.33 



Rabbit 6 14.4 0.89 0.99 2.50 



* According to more recent data the young pig may double its weight in 8 or 10 days. 



The infant, which requires about 180 days to double its weight, re- 

 ceives a milk containing but 1.6 per ct. protein, 0.03 per ct. lime, 0.05 

 per ct. phosphoric acid, and 0.20 per ct. total ash, or mineral matter. 

 The shorter the time required by the new-born young of different species 

 to double in weight the larger is the content of protein and of mineral 

 matter, especially lime and phosphoric acid. It thus appears that there 

 has been provided for the young of each species milk of the composition 

 needed for the development characteristic of that species. These studies 

 emphasize the necessity of maintaining a liberal supply of protein and 

 mineral matter in the ration of young animals as the mother's milk is 

 replaced by other feeds during their early life. 



117. Rich and poor milk for young animals. Beach of the Connecticut 

 (Storrs) Station 10 fed calves, pigs, and lambs on skimmed milk, ordinary 

 milk containing from 3 to 3.5 per ct. fat, and rich milk containing from 

 5.1 to 5.7 per ct. of fat. The lambs also received a small quantity of hay. 

 Calves fed rich milk required 1.18 Ibs. milk solids, including fat, to pro- 

 duce 1 Ib. of gain, while others fed milk low in fat required only 1.03 Ibs. 

 The same results were, secured with lambs and pigs. 



'Abderhalden, Ztschr. physiol. Chem., 27, 1899, p. 594. 

 "Conn. (Storrs) Bui. 31. 



