TWO SYSTEMS OF FEEDING DAIRY COWS 



Table 5. — Changes in Body Weight. 



(a, Actual weight not available; weight estimated from previous year's records. 

 (6) Loss. 



made for the difference in time interval. Even after making this allowance, how- 

 ever, the low roughage group had some advantage insofar as gains in weight were 

 concerned. These data bear out the general observation noted from time to time 

 and referred to on p. 6 that the high roughage group showed a tendency to be 

 rather thin, due probably in part to the slightly smaller amount of feed eaten. 



Milk Yield 



Milk production records are available for fourteen complete lactation periods 

 in each group. Records of partial lactation periods have not been included because 

 there is no known method of correcting them so that they will be comparable. 

 The complete records as reported in Table 6 have all been corrected to a 305-day 

 basis with proper allowance made in each case for length of time a calf was carried 

 during the lactation. * 



The corrected daily milk yield per cow was almost exactly four pounds, or 14.4 

 per cent, more in the low roughage group than it was in the high roughage group. 

 The number of lactations being the same, the total production was, of course, cor- 

 respondingly higher in the low roughage group. It is to be expected that cows get- 

 ting a liberal allowance of grain will milk more freely than if on a restricted 



*These corrections were made by using the factors published by Gaines and Davidson in Illinois 

 Experiment Station Bulletin No. 272, pages 25 and 34, Tables 7 and 8. Correction for age was 

 unnecessary as the average age of both groups was approximately the same throughout the investi- 

 gation. 



