FARMERS' MONTHLY OF HAMPSHIRE COUNTY 



11 



quantity and quality of roughage is fed, 

 to each, the high producer will require 

 a lower protein grain. 



Suppose two cows of similar weight 

 and breed are giving respectively twenty- 

 five pounds and fifty pounds of milk 

 daily, and each cow is eating 12 lbs. of 

 mixed hay and .30 lbs. of corn silage. 

 The 2.5 lb. cow will need 6 lbs. of grain 

 containing 24'/^ protein in addition to her 

 roughage. The 50 lb. cow will need near- 

 ly 16 lbs. of grain containing 20'/ pro- 

 tein in addition to her roughage. 



A following letter will contain some 

 more suggestions for feeding producing 

 cows, dry cows and young stock. 



Prof. C. J. Fawcett. 



Effect of Age and Development on Butterfat 

 Production of Official Tested Dairy Cows 



It is well known that the butterfat yield 

 of a heifer is not so large as that of the 

 same cow at mature age. Hence it is 

 impossible to compare records made by 

 cows of different ages without adjusting 

 for age differences. To determine the 

 value of a sire for breeding purposes it is 

 necessary to compare his daughters with 

 their dams; and cows are not all tested 

 at the same age. It is customary, there- 

 fore, to assume a certain average rate of 

 increase for every six months of age, and 

 on this basis to calculate the mature pro- 

 duction of a cow from her record at an 

 earlier age. 



The Bureau of Dairying of the United 

 States Department of Agriculture has 

 been making careful studies to ascertain 

 the actual relationships of the production 

 records of cows at different ages. These 

 studies, which are reported in Depart- 

 ment Bulletin 1352, just issued, were 

 made with Guernseys and Jerseys. A 

 lai'ge number of official records were 

 classified according to age, and it was 

 found that the increase for every six 

 months is much larger in the earlier six- 

 month periods than it is as the cows ap- 

 proach maturity. Since the official test- 

 ing requirements used by the breed as- 

 sociations assume equal increments for 

 all the six-month periods, it appears that 

 heifers are considerably favored by the 

 existing requirements, while cows of 

 more than three years are expected to in- 

 crease faster than they actually do. 



For both Jerseys and Guernseys the 

 existing requirements assume maturity 

 at the age of five years; but the studies 

 made indicate that Guernseys are likely 

 to mature a few months later, and .Jer- 

 seys not until the age of six years. There 

 is no increase in the official requirements 

 after the age of five years, but in fact it 

 is found that the records do improve, 

 which gives an advantage to the older 

 cows, though not .so great an advantage 

 as is given to heifers. 



In the study made by the Bureau of 

 Dairying, it was found that cows retested 



are able to make higher records than 

 those that have never been tested before. 

 For this reason, only initial records are 

 used in the tabulation that shows the ef- 

 fect of age. 



The difference between initial and re- 

 entry records represents two elements; 

 one is the increment due to age, and the 

 other is that due to development result- 

 ing from special care given to young cows 

 undergoing their first test. There is suf- 

 ficient evidence to prove that ofiicial test- 

 ing develops the productive ability of 

 dairy cows, and that the feeding and care, 

 combined with the prolonged milking 

 period during which the cow is encouraged 

 to yield her utmost, have a positive and 

 appreciable effect on her production dur- 

 ing subsequent lactation periods. It ap- 

 pears that close to one-third of the im- 

 provement made in the re-entry record is 

 the result of this development factor. 



Another fact brought out by these 

 studies is that pregnancy during the test 

 reduces butterfat production, and the tax 

 of pregnancy seems to increase with ad- 

 vancing age. While the young animal 

 carries on the function of reproduction 

 without affecting materially her produc- 

 tive capacity, the older cows do not stand 

 up so well under the double strain. 



A further interesting fact in this con- 

 nection is the noticeable improvement in 

 production records made since the be- 

 ginning of 1920, especially in the last one 

 thousand records. The rise is gradual, 

 and seems to indicate that with the in- 

 crease in experience gained by handling 

 test cows the breedeis have developed 

 better methods of feeding, conditioning 

 and caring for animals on test. The ef- 

 fect of years of selective breeding for 

 high production is also a force operating 

 to raise these averages. Re-entry records 

 made after a lapse of six years show a 

 larger increase due to development than 

 those made after a shorter interval. 



The bulletin may be obtained by ap- 

 plication to the United States Department 

 of Agiiculture, Washington, D. C. 



FARMERS' EXCHANGE 



FOR SALE: Two Registered Hol.stein 

 heifer calves, dropped August and De- 

 cember. John Reid, South Hadley, Mass. 



WANTED: Names of Holstein Breed- 

 ers having bull calves for sale. Cow test 

 or advance registry records of dams must 

 be shown. J. A. Simms, Connecticut 

 Agricultural College, Storrs, Conn. 



FOR SALE: Single Combed Rhode 

 Island Red cockerels. Carefully selected 

 for type, vigor, color and production. 

 Price $5.00 each. Frank Steele, Cum- 

 mington, Mass. 



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