FACTORS INFLUENCING THE WORK OF THE HORSE 293 



percentage of the total energy in the feed which he is able to convert 

 into useful work. 



A 1,500-lb. horse should readily haul a load having a draft of 150 Ibs. 

 at a speed of 2.5 miles per hour for 8 hours a day. In doing this the 

 horse will perform 7,920 foot-tons of useful work, not including the 

 work of moving his own body along the roadway. Expressed in therms, 

 this amount of work is equal to 5.13 therms. 



For such a horse a ration of 15 Ibs. timothy hay, 8 Ibs. corn, 8 Ibs. 

 oats, and 1.5 Ibs. linseed meal will be satisfactory. This ration will 

 furnish about 57.19 therms of gross energy. Dividing 5.13 therms 

 (the useful work accomplished) by 57.19 therms (the gross energy of 

 the feed) gives an over-all efficiency for this horse of 8.95 per ct. This 

 is higher than the average over-all efficiency of 65 modern farm tractors, 

 which was found to be 8.05 per ct. in tests at the University of Nebraska 

 in 1920. (143) 



However, farm horses do not work every day, tho they must eat every 

 day. Therefore the over-all efficiency for the entire year is much lower 

 than for a 24-hour period in which the horse does a good day's work. 

 On the average, the yearly over-all efficiency of farm horses, which 

 usually work only about 800 to 1,000 hours a year, is about 2 to 3 per 

 ct. 18 Obviously, any factor which increases the number of hours of work 

 a horse does during the year increases his over-all efficiency and reduces 

 the actual cost of his labor per hour, for less of his feed will then go 

 for maintaining him when idle. 



459. Reducing the cost of horse labor. Horse labor makes up a rel- 

 atively large part of farm operating expenses. Moreover, it is, 

 above all other items of expense, the one which can be profitably reduced 

 by good methods of farm organization. Hence a clear understanding of 

 the following ways in which this expense can be lessened is of prime 

 importance : 19 



(1) By economical feeding, care, and management. Farm manage- 

 ment surveys have shown that it costs some farmers nearly twice as 

 much to feed their horses as it does their neighbors, tho the horses may 

 do but little more work. Thru economical feeding the cost of horse 

 labor may thus be greatly reduced. 



(2) By raising good colts. Even tho the direct profits to be made in 

 raising colts may not be large, successful farmers, at least in the corn 

 belt and westward, find it economy to raise enough well-bred colts to 

 replace the older horses worn out or sold to avoid depreciation. 



(3) By reducing depreciation charges. As is pointed out in the 

 following chapter, many farmers largely avoid the depreciation in the 

 value of horses due to their becoming old, by raising good colts, starting 

 them to work when 3 years old, and selling them after working 4 or 5 

 years, when they are yet in their prime and bring good prices. 



18 E. A. White, Breeder's Gazette, June 2, 1921, p. 997. 



"Largely adapted from Handschin, Andrews, and Rauchensteln, 111. Bui. 231. 



