FEEDING WORKING ANIMALS 395 



487. Nutritive ratio for working horses. — Concern- 

 ing the nutritive ratio or proportion of protein in a ration 

 designed for working horses, there is a variety of recom- 

 mendations. The German standards call for ratios from 

 1 : 7 to 1 : 6, according to the severity of labor, the daily 

 weight of protein for a 1,000-pound horse to be from 1.5 

 to 2.5 pounds. This is greatly more protein than is 

 recommended by Lavalard, who, on the basis of exten- 

 sive experience, declares that 1.15 pounds of protein 

 daily is sufficient for ordinary work, this to be increased 

 to 1.35 pounds when the labor becomes more severe. 

 There is one fundamental fact that is pertinent to a dis- 

 cussion of this point, which is that the non-nitrogenous 

 constituents of the ration are largely the soiu-ce of muscu- 

 lar energy. As stated before, it was formerly thought 

 that muscular effort was sustained at the expense of 

 muscular tissue, but when it was found that no more urea 

 was excreted by men climbing a mountain than when 

 they were much less active, this view was abandoned. 

 Later researches have clearly shown that when work 

 increases the excretion of carbon dioxid increases in like 

 proportion without any important rise in the protein 

 exchange. In other words, the carbohydrates and fats 

 are largely the fuel that supplies energy for mechanical 

 purposes. Common experience ratifies this conclusion 

 of science. Many horses and oxen, have successfully 

 endured severe labor on meadow hay, oats, and corn, 

 sometimes the grain being largely the latter. 



A ration properly compounded from ordinary farm 

 products, such as silage, roots, meadow hay, legume hays, 

 and the cereal grains, will generally contain protein in 

 sufficient proportion, and will seldom need reinforcing 

 with the nitrogenous feeding-stuils. It is probably true. 



