4 BULLETIN 945, U. S. DEPARTMENT OF AGRICULTURE, 
noticeably during the routine treatment. After several years of the 
routine treatment cow 17 was given an unusually long dry period 
before calving, and cow 201, a more liberal ration for some weeks be- 
fore calving. In both cases the subsequent milk yields were 
markedly increased. (See p. 13.) 
The increase in the milk yields of these cows is due in the one 
case to the more liberal ration supplied before the calf was born; 
and in the other to the long dry period with a supermaintenance 
ration. The rations fed after calving bore about the same relation 
to the milk yield as they had in previous years. It may be added 
that the milk yield for the first few weeks of lactation is not very 
closely dependent on the contemporaneous food supply (2). 
DEC. 
1 1 1 .1 1 1 1 .-.1 1 
1914 
OCT 
19)5 
OCT 
19/6 
OCT 
1917 
DEC 
1918 
I r F i i i 1 i i i i i 
t 2 3 4 5 6 7 e 9 10 II \Z 13 14 
HUMORED POUNDS OF MILK 
Fig. 2. — Influence of the length of the dry period and of the ration fed during that period 
on the subsequent milk yield in the case of cow 201. The columns represent the pounds 
of milk given jn the first clear calendar month after calving in the years indicated. 
Before calying in the years 1914 to 1917, inclusive, this cow was fed the routine ration 
for dry cows at Beltsville ; her dry periods averaged 50 days. Before calving in Decem- 
ber, 1918, she was given a dry period of 78 days, and during the last 40 days of this 
period was fed a much more liberal ration than the previous one. (See pp. 13 and 14.) 
The course of events which these two cows illustrate is typical. 
Several similar histories could be presented. Indeed, it has been the 
rule on this farm that greatly increased milk yields were obtained 
when cows from the general herd were dried off two months or more 
before they were due to calve and fed liberally during the dry period. 
Cows 17 and 201 were selected as examples, not because the downhill 
course of their milk yields on the routine treatment was particularly 
rapid or the subsequent recoveries particularly marked, but simply 
because they had been freer from disease and from disturbing ex- 
periments during their stay at Beltsville than others which might 
have been selected. It is, therefore, a very moderate statement of 
the case to say that' average and high-producing cows often do not 
maintain anything like their optimum milk yield when they are bred 
to calve once a year and fed for several years approximately accord- 
ing to the most liberal of the American feeding standards, even 
