This section is from the book "The Horse - Its Treatment In Health And Disease", by J. Wortley Axe. Also available from Amazon: The Horse. Its Treatment In Health And Disease.
Heavy dray-horses require from 28 lbs. mixed food to 33 lbs. or 34 lbs., according to their size and the severity of their work, and whenever more is required it is the result of some attendant waste. About 27 lbs. or 28 lbs. of mixed food of equal parts of grain and hay will usually supply the requirements of farm horses. Tram and omnibus horses are usually allowed from 26 lbs. to 30 lbs. Other horses will require food in a corresponding ratio, according to their size and work. Horses at rest will do with a third less food than when doing severe work.
 
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