IU, 6 ; fr *LTJ 
 
 U. S. DEPARTMENT OF AGRICULTURE, 
 STATES RELATIONS SERVIC3 
 
 A. C. TRUE, Director. 
 
 
 HOW TEACHERS MAY USE FARMERS' BULLETIN 743, 
 THE FEEDING OF DAIRY COWS. 
 
 Range of use. — All districts in which dairying is of any impor- 
 tance. 
 
 Relation to the course of study. — The bulletin will assist in the 
 study of animal husbandry, especially in dairy practice, in the course 
 in agriculture, and suggests suitable correlations with other school 
 branches. 
 
 Topics. — The following grouping of topics is suggested for school 
 use: A. Fall and winter lessons; (1) the need of liberal feeding, 
 pages 1-3; (2) succulent feed, silage, and roots, page 9; roughage, 
 page 10; (3) the balanced ration, pages 11 and 12; (4) nutritive 
 value, etc., of grains and concentrates, pages 13-17; (5) rules for 
 making grain mixtures, pages 18, 19; (6) selection of sample grain 
 mixtures for local use, pages 19-2*^: (7) amount of roughage and 
 grain, allowances for individual cow. pages 22, 23. B. Spring les- 
 sons; (8) pasturage, pages 3. 4; (9) supplements to pasture, grain, 
 soiling crops, summer silo, pages 5-8. In a brief course this may 
 be covered in a very few lessons, but in a more extended course each 
 subdivision suggests more intensive study with home practice. In 
 this case the questions which follow will lead to the use of bulletins 
 published by the experiment stations of the respective States, also 
 texts on feeds and feeding. 
 
 Study questions. — What is a maintenance ration? What does the 
 maintenance ration accomplish? To what extent should the ration 
 be increased beyond the maintenance ration? In winter feeding, 
 what factors must be considered \ Why are home-grown feeds gen- 
 erally desirable? Give examples of roughage, succulent foods, and 
 concentrates for winter use. Which of these may be grown in this 
 district? What are the relative advantages of silage and roots? 
 Why can not the entire ration be made of roughage? What advan- 
 tages has the leguminous hay over timothy hay or corn fodder? 
 What is meant by the term " balanced ration r ' ? Why is this balance 
 important? To what extent should cost determine the ration? 
 Which of the concentrates described are suited to local use? How 
 may a grain mixture be compounded? Select grain mixtures for 
 use with high, low, and medium protein roughages which might be 
 obtained in the district. What economy is there in using high- 
 
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 protein roughages? How much of roughage and of grain should 
 be fed to a cow? Why is an abundance of pure water necessary? 
 How secured ( How salt the cows ? What is the value of pasturage ? 
 What supplements to pasturage are profitable? Discuss the relative 
 value of grain, soiling crops, and summer silage as pasture supple- 
 ments. 
 
 Illustrative material. — The pupils should collect samples of all the 
 home-grown feeds and all those purchased in the district. Before 
 they leave the subject, have them preserve and label these specimens 
 for the school museum. (See Farmers' Bulletins 586 and 606.) 
 Have the pupils collect printed price lists of grain and other feeds. 
 Graphic charts of the digestible nutrients of the more common 
 feeds may be copied from bulletins. 
 
 Practical exercises. — Have as many pupils as possible try weigh- 
 ing milk and modifying rations of cows at home, in cooperation with 
 their parents. Have a survey made of the dairy farms to include 
 such data as amount of roughage grown on farm, amount of succu- 
 lent feed, grain grown, amount of concentrates purchased, practice 
 in feeding, method of balancing rations, method to determine amount 
 of feed necessary, etc. Some pupils who are interested in dairying 
 may take up a home project in dairying, weighing the milk of each 
 cow, computing rations, testing milk, finding cost, income, and 
 profit. 
 
 Correlations. — Have pupils compile the survey charts and compute 
 the expense of rations in different cases. Use the local prices for hay 
 and grain to determine the cost of different rations suggested in the 
 bulletin. Use outline maps of the State and of the United States and 
 indicate the source of feedstuffs used in the district, also the lines 
 of transportation used. Look up freight rates and compute the rel- 
 ative loss due to long hauls on different feeds, especially those which 
 might be grown in the district or others which have too low feeding 
 value. 
 
 In the physiology class, discuss the different digestible nutrients 
 in various feeds which may be used by persons as well as by cattle* 
 Compare the demands of the human system for food with those of 
 the cow, selecting points in which they are similar and those in 
 which they are different. Consult other bulletins on grain crops used 
 as human food, such as Farmers' Bulletins 121, 298, 559, and 565. 
 
 F. E. Heald, 
 Specialist in Agricultural Education. 
 
 Approved : 
 
 C. H. Lane, 
 
 Chief Specialist in Agricultural Education. 
 
 September 29, 1916. 
 
 WASHINGTON '. GOVERNMENT PRINTING OFFICE \ 1916