408 



NUTRITION OF FARM ANIMALS 



Bull and Emmett 1 have compiled the results of fifty American 

 experiments on fattening lambs, comprising 5127 animals, 

 and computed the protein and net energy content of the rations 

 consumed. They divide the animals into four classes accord- 

 ing to the live weight, and subdivide these classes into groups 

 according to the amount of digestible protein consumed. A 

 comparison of these groups shows in general that in each class, 

 even with a liberal supply of feed energy, the rate of growth 

 increased as the supply of protein increased up to a certain 

 fairly well-defined amount, beyond which a further increase 

 of protein had in general little or no effect. The authors es- 

 timate the amounts of digestible protein necessary to ensure 

 satisfactory gains by fattening lambs as follows : 



TABLE 99. ESTIMATED PROTEIN REQUIREMENTS OF FATTENING LAMBS 



On the other hand, Just's results on lambs recorded in Table 

 88 (471), like those of Fingerling in calves, point to a much 

 lower protein requirement. 



488. Experiments with swine. As is illustrated in Table 

 93 (481 b), the swine is distinguished above other farm quad- 

 rupeds by its very rapid growth, especially in the earlier stages. 

 The young pig is able to double his weight in little more than 

 a week and to nearly treble it in two weeks, a rate of growth 

 reached or exceeded by no farm animal with the possible ex- 

 ception of young fowls. 



Such a rapid rate of growth implies, of course, a correspond- 

 ingly large storage of protein, a conclusion fully confirmed by 

 the investigations of Ostertag and Zuntz, of Wilson, and of 

 Sanford and Lusk, cited in i (463) which showed an average 



1 Ills. Expt. Sta., Bui. 166 (1914). 



