18 MISC. PUBLICATION 702, U. S. DEPT. OF AGRICULTURE 



But production obtained from feeds is likely to be changed in the 

 process of modifying rations. An understanding of the extent of 

 change in output of livestock products, as the ratio between forage and 

 concentrates in the ration varies, is essential to a full exploration of 

 utilization of forage by livestock. 



DAIRY CATTLE 



Numerous dairy-cattle feeding investigations have been carried out 

 at Federal and State experiment stations to study the problem of in- 

 cluding more and better roughage in rations fed dairy cows. Gener- 

 ally, these investigations have involved high-producing cows and ex- 

 cellent roughage. The hay fed has usually been alfalfa. The cows 

 have been handled apart from other phases of farming by skilled 

 technicians. The findings are good guide-posts, but because of these 

 features of the experiments, results obtained are difficult to interpret 

 for farm conditions. Farmers use many low-producing cows and 

 much low-quality roughage. The dairy enterprise generally is part 

 of a farming system rather than the whole farm business. 



In one feeding experiment 12 cows were fed through 4 lactation pe- 

 riods {11). Their milk and butterfat productions on four planes of 

 feeding were studied. It was found that when cows received alfalfa 

 hay alone or good pasture alone they produced only 70 percent as much 

 milk as when fed a ration of alfalfa hay, corn silage, pasture in season, 

 and concentrates at an average rate of 1 pound of grain for each 4.3 

 pounds of milk produced. With corn silage added to alfalfa or 

 pasture, the cows produced 73 percent as much milk as when full fed. 

 The addition of ground barley to alfalfa hay or pasture alone, when 

 fed at the rate of 1 pound to 6 pounds of milk, resulted in the cows 

 producing 86 percent as much milk as when full fed. Other experi- 

 ments (10; 25; 21, pp. 33-35), indicated findings generally in the 

 same direction as these, but the exact relationships observed between 

 production of milk from a full feed compared with that from a ration 

 of roughage alone, or some other ration representing less than a full 

 feed, have varied. Woodward (40, pp. 47-55) reckoning with the 

 numerous results made the observation that : 



The guess from these data is that a ration composed solely of good alfalfa when 

 fed to good cows milked twice a day will support a production of as much as 

 0.8 pound of butterfat a day as an average for the lactation period or approxi- 

 mately 250 pounds a year, if the cows calve every 12 months. Substituting corn 

 silage for a part of the alfalfa will increase the production to approximately 275 

 pounds ; and if cows have first-class pasturage along with the alfalfa hay and corn 

 silage, it is possible to further increase the production to 300 pounds of fat in 

 a year. 



His summary data indicated also that the feeding of a small to 

 moderate quantity of grain along with good forage increased the out- 

 put of butterfat about 17 percent (from 300 to 350 pounds) compared 

 with that obtained from the feeding of a good all-roughage ration 

 made up of alfalfa hay, corn silage, and pasturage. Considering all 

 facts from these materials, one perhaps could do no better than gen- 

 eralize that good cows fed a limited grain ration (1 pound of grain to 

 6 pounds of milk) along with all the good alfalfa hay, corn silage, and 

 pasturage they want will produce approximately 90 percent of their 

 output of milk under a full-grain ration ( 1 pound of grain to 3 pounds 

 of milk) . Eemoving the grain from the previous ration their produc- 



