12 MASS. EXPERIMENT STATION BULLETIN 406 



Flavor of the Milk 



The milk from all four groups of cows was scored for flavor on two occasions 

 (June and September '41) by a qualified flavor expert who did not know the 

 identity of the samples. Scoring was done twice on each lot of samples: the first 

 time about eighteen hours after the samples had been taken and cooled, and the 

 second time about twenty-four hours after the first. Average scores as shown in 

 Table 13 indicate that flavor differences were either very slight or nonexistent. 



Table 13. — Average Milk Flavor Scores 

 (Based on a possible score of 25) 



June Samples September Samples 



Average 



1st Day 2d Day 1st Day 2d Day 



Regular Ration 



"Double Reversal" group 23.00 23.00 22.00 21.00 22.25 



"Continuous" group 22.50 22.50 21.00 20.00 21.50 



Urea Ration 



"Double Reversal" group 22.00 22.00 22.00 20.00 21.50 



"Continuous" group 22.00 21.00 22.00 21.00 21.50 



Results from the "Control" Ration 



It has been noted (see p. 4 and Table 2), that a so-called control ration was fed 

 to certain cows in the herd from time to time in the course of the experiment. 

 This was done in order to be sure that the basal ration (i. e., the urea grain mix- 

 ture minus the urea) was inadequate for sustained milk production. 



Two cows not included in Groups A, B, C, or D were fed this control ration 

 for a time soon after the commencement of the feeding trials in 194C, and two 

 others for a somewhat longer time in 1941. The first two fell off very rapidly 

 in milk production after being placed on the control ration, while the others 

 managed to maintain what seemed like a fairly normal level of production. Be- 

 cause of these rather conflicting results, it was decided when the main experiment 

 was concluded at the close of the 1941 lactation, to run a somewhat larger group 

 on the control ration during 1942. Six cows were chosen, three each from Groups 

 C and D, the so-called continuous groups, and were fed the control ration from 

 soon after freshening time in the spring of 1942 until the middle of December. 



Because of unforseen circumstances and difficulties, some of them a direct re- 

 sult of the war emergency, the results for the full seven months of this last phase 

 of the work cannot be used in entirety. There is, however, a period of twenty 

 weeks, extending from the thirteenth to the thirty-second week inclusive, of each 

 cow's lactation, which is reasonably free of the above-mentioned vicissitudes and 

 the production data from which are rather clear cut. They are graphically 

 portrayed in Figure 2, in contrast with the records for these same cows for the 

 same portion of their 1940 and 1941 lactations. It seems evident that the con- 

 trol ration was inadequate to support milk production at the level of the two 

 previous lactations. This conclusion is derived not only from the somewhat 

 lower production level (on either an actual or a percentage basis) in the 1942 

 lactation, but also from the marked flattening of the 1942 shrinkage curve from 

 about the twenty-fourth week onward, a change which apparently contradicts 

 the conclusion. The contradiction, however, is only apparent, for this change 

 took place soon after the introduction into the ration of alfalfa silage. This move 



