100 



FEEDS AND FEEDING, ABRIDGED 



The Eckles standard. — From experiments at the IMissouri Station ^ 

 and from the work of Savage and Armsby, Eckles has drawn up a 

 standard according to the Armsby system, showing the requirements 

 of cows producing milk containing various percentages of fat. This 

 also is given in the next table. 



Comparison of standards for dairy cows. — In the following table 

 the Haecker, Savage, and Eckles standards are brought together for 

 comparison. Haecker 's figures have been converted into total digest- 

 ible nutrients as in the Savage standard. The Woll-Humphrey stand- 

 ard cannot be included for it is not based on the percentage of fat in 

 the milk, but upon the daily yield of fat. 



Feeding standards for dairy cows compared 



The Haecker and Savage standards agree in the requirements for 

 maintenance. Savage's digestible crude-protein requirement for pro- 

 duction is higher in each ease, as already pointed out. In total digest- 

 ible nutrients he agrees quite closely with Haecker. As Eckles' 

 standard is expressed in digestible true protein (not crude protein) 

 and therms, it cannot be directly compared with the others. By com- 

 puting the amount of true protein and crude protein in typical good 

 dairy rations, it will be found that if Eckles' figures were changed into 

 crude protein they would be even higher than Savage's. Similar com- 

 parisons show that Eckles' standard calls for about the same amount of 

 total digestible nutrients for milk low in fat, but up to one-fifth more 

 for rich milk. 



From the foregoing w^e may conclude that when protein-rich feeds 

 are high in price compared with those low in protein, it will usually be 

 economical to feed no more protein than is called for by the Haecker 

 standard, at least to cows of average production. On the other hand, 



7 Mo. Res. Bui. 7. 



