22 CIRCULAR 443, U. S. DEPARTMENT OF AGRICULTURE 



In feeding dairy animals when the entire ration consists of dehy- 

 drated forage, the production of milk and butterfat is about 60 to 

 70 percent of the production made on a full-grain ration. In an experi- 

 ment conducted by the Bureau of Dairy Industry at the Lewisburg, 

 Tenn., station, 16 registered Jersey cows made 17 lactation-period 

 records on rations restricted to machine-dried hay (largely legume) 

 and pasture. Their average production, calculated to a mature- 

 equivalent basis, for an average lactation period of 361 days was 

 6,333 pounds of milk and 329 pounds of butterfat. The average loss 

 in body weight was 33 pounds to the end of the lactation, but this 

 does not take into consideration gains that normally would be made 

 during the dry period prior to the next calving. The same cows made 

 comparable records under register-of-merit testing conditions when 

 they were fed machine-dried legume hay, pasture, and liberal amounts 

 of a grain mixture. Under these conditions the same cows produced 

 an average of 9,656 pounds of milk and 527 pounds of butterfat with 

 an average gain of 70 pounds in body weight to the end of their lacta- 

 tion period. On the roughage-alone ration the cows produced 66 per- 

 cent as much milk and 62 percent as much butterfat as they produced 

 under the register-of-merit conditions. During the time the cows 

 received hay without pasture they consumed an average of 28.6 pounds 

 of hay per cow a day, or at the rate of 3.44 pounds of hay per 100 

 pounds of body weight. 



However, in feeding forage to animals, the question of palatability 

 is an important factor and artificially dried hay is very palatable to 

 animals. Some forage plants such as the clovers and alfalfa appear to 

 be more readily consumed by the animals than the coarser, heavy- 

 stemmed legume forages such as soybeans and cowpeas. Artificially 

 dried hay will be uniformly good if the hay is cut at the proper stage 

 of maturity, while much of the Dutritive value of field-cured hay 

 may be lost hi any given year due to unfavorable weather conditions 

 for field curing. Machine drying is an insurance against losses in 

 quality of hay that results from unfavorable weather conditions for 

 field curing. 



Two experiments, conducted at the Western Washington Experi- 

 ment Station by the Bureau of Dairy Industry and the Washington 

 Experiment Station, have a bearing on the nutritive value of artifi- 

 cially dried pasture grasses. These experiments were conducted with 

 a small experimental rotary-drum drier. In view of the fact that the 

 drying material is not expected to attain a higher temperature than 

 that of the gases at the outlet from the drier, the outlet temperatures 

 in these experiments were taken as the temperature of drying. How- 

 ever, as the material dried in passing from the feed end to the dis- 

 charge end of the machine it was subjected to temperatures in excess 

 of that indicated as the exhaust temperature. 



Artifically dried roughage that has a minimum of exposure to sun- 

 light after cutting is thought likely to be deficient in vitamin D. The 

 first experiment 6 was conducted to determine the comparative cal- 

 cifying powers of similar samples of green, artificially dried, and sun- 

 cured pasture herbage. It was found that pasture herbage when fed 

 in a green, artificially dried, or sun-cured form, constituting 3 percent 

 of the dry matter in the ration, caused a significantly greater degree 

 of calcification in rats than did the basal diet. Increasing the amount 



6 Hodgson, R. E., and Knott, J. C. the calcifying properties of green, artificially dried and 

 sun-cured pasture herbage. Jour. Agr. Research 48: 439-446. 1934. 



