224 FEEDS AND FEEDING, ABRIDGED 



fattening animals. With both these classes, after growth is completed 

 the ration may consist largely of carbohydrates and fat, with only 

 sufficient protein to ensure complete digestion of the ration. 



It is not necessary, and is often not advisable nor economical, to 

 furnish as much digestible crude protein in the ration as stated in the 

 ^Yolff-Lehmann standard. (See Appendix Table IV.) Horses at hard 

 work have been fed for considerable periods without harm on rations 

 having nutritive ratios as wide as 1:28.0. However, as shown on 

 Page 47, when the nutritive ratio is wider than 1 :8.0 or 1 :10.0, the 

 digestibility of the ration is decreased and feed is wasted. 



Feeding standard for horses. — From a study of American and 

 European investigations, the authors have prepared the following 

 standard (given also in Appendix Table V), which states in simple 

 terms the nutrient requirements of idle horses, and of those performing 

 light, medium and heavy work. 



Modified Wolff -Lehmann standard for horses 



Per day per 1,000 lbs. live weight 



Dry Disrestible 



matter crude 

 protein 



Lbs. Lbs. 



Idle horses 13.0-18.0 0.8-1.0 



Horses at light work . . 15.0-22.0 1.1-1.4 



Horses at medium work lG.0-24.0 1.4-1.7 



Horses at heavy work . 18.0-2G.0 2.0-2.2 



It will be noted that while only 5 to 8 lbs. more dry matter is advised 

 for the horse at hard work than for one which is idle, he requires 8.9 to 

 10.5 lbs. more total digestible nutrients. This means that the idle horse 

 can be maintained on such feeds as hay alone, which is low in total 

 digestible nutrients, and furnishes but relatively little net energy. 

 However, the ration for the hard-worked horse must be more concen- 

 trated in character, containing a much smaller proportion of hay or 

 other roughage. As the work becomes harder, a slightly narrower 

 nutritive ration is advisable. The amount of protein here stated is the 

 tninimum advisable, and considerably more may lie supplied if protein- 

 rich feeds are lower in price than carbonaceous feeds. 



Influence of speed on work. — The horse is at his best for drawing 

 loads when moving at a rate of 2 to 2.5 miles per hour. If held to a 

 slower pace and especially if urged to move faster, his efficiency 

 decreases. AVhen worked at the rate of 11.25 miles per hour, he 

 accomplishes less than one-tenth of the amount of work of which he is 

 capable. \A^hen trotting with no load the horse expends nearly twice 

 as much energy per mile of travel as when walking. Among the rea- 

 sons why more energy is recpiired to perform a certain amount of work 



