362 MASS. EXPERIMENT STATION BULLETIN 260 



In 1929 the herd included 20 cows milked during the year. A number, 

 however, had only short lactation periods, varying from a few days to 

 six months. The records of ten cows having normal lactation periods are 

 as follows: Average yearly production 8534 pounds, testing 12.40 per 

 cent total solids and 3.97 per cent fat, with a feed cost of $143-63 per 

 cow, and 3.70 cents per quart of milk. The feed cost of roughage was 

 figured on the same basis as for 1928, with grain at prevailing market 

 prices. The feed cost of milk M'as a little less in 1929 than in 1928 due, 

 in a measure, to the increased use of roughage and less grain. 



Milk Substitutes in the Growing of Young Calves. (J. B. Lindsey and 

 J. G. Archibald). Results of -work on this project over a period of 

 several years have recently been published in Bulletin No. 253. The 

 method which has been the most satisfactory compromise between economy 

 ajid good growth has involved the use of skim milk powder in limited 

 amount (about 125 pounds per calf) up to four months of age. 



The project is being continued with the idea in mind of developing a 

 system based largely on dry feeding after the first few weeks, little or 

 lio liquid except water being fed. 



Mineral Supplements for Dairy Cattle. (J. B. Lindsey and J. G. Archi- 

 bald). The final report of six years" investigation of this subject has 

 recently been published in Bulletin No. 255. Little, if any, benefit was 

 noted from the feeding of bone meal. Some slight benefit was noted) 

 from feeding dicalcium phosphate (precipitated bone), but not sufi'icient 

 to warrant recommendation of its general use. Average producing cows 

 (5000-8000 lbs. yearly) fed on good quality roughage with the amounts 

 of grain ordinarily fed in New England seem to obtain sufficient mineral 

 matter from their ordinary feed. Heavy producers may benefit from the 

 addition of mineral supplements, but the efficacy of the practice is Uy 

 no means well established. 



Mineral Cjonstituents of Forage Crops. (J. B. Lindsey and J. G. 

 Archibald). Results of this project form a part of the above-mentioned 

 Bulletin No. 255. No pronounced deficit of mineral constituents has been 

 noted in the 'Massachusetts roughages exaimined in the course of this 

 work. The calcium content of the hays analyzed is worthy of note, it 

 being somewhat higher than the values given by other authorities- 

 Mineral Requiirements for the Growth of Dkiry Heifers. (J. B. Lindsey 

 and J. G. Archibald). Work on this project, organized about three years 

 ago, is being actively pursued. At date of writing (Decemiber, 192'9) 

 eight heifers have been carried through two years of intensive experimen- 

 tal trials, four on a ration high in calcium, and four on a raition low in 

 that element. An accurate check has been kept on the intake and excre- 

 tion of calcium and phosphorus by these animals, and careful growth 

 records have been kept. The work has not yet reached a stage where 

 definite conclusions are warranted. Of necessity it must be a long-time 

 project. 



A Comparison of Two Systems of Dairy Cattle Feeding — High Rough- 

 age and Low Grain vs. Low Roughage and High Grain. (J. B. Lindsey 

 and J. G. Archibald). This project was organized a year ago in order 

 to obtain some definite experimental evidence on a problem which is 

 much discussed by practical feeders and on which various recommendations 



