A STUDY IN MILK SECRETION. 139 
TABLE 62. 
Average Daily Fat Yield of Eight Cows. 












| PERIOD I, PERIODII. Milked Three Times Daily. PERIOD III 
NAME OF | Milked | ; Milked 
Cow. ) ‘Twice | S15 4.M. | 1A. Mo | 4.45 P.M. Total Meriee 
ares ; 
| pee Pounds. Pounds. Pounds. | Pounds. ss 
| Pounds. | Pounds. 
Olive, : Mind <OSN © 491 .495 .305 .495 1.355 1.079 
Holstein. --) 1.050 | .479 .335 .498 i302 I .008 
Butterfly, s--+| O30 Em) 425 .485 . 204 POLE .gII 
Doth Dy « PL Sw | .511 . 330 473 1.314 TOs? 
Black, - - Te200 .514 .495 ¥2 EL 1. 220 27a 
Biacks [is = 40 i264 | .547 5071 5210 £437 eoe 
Fairview, - | 1,058 .543 b4.02 .168 Dew 733 1,223 
Stella 9 Ue. .751 384 e201. i 7 Ome: 845 -799 
Avetagve, ~- | 1,065 | .487 By 2305 9 heel 220 reaayas 
Total, Halen. 35 23.) 2 3.898 3.434 STAR b= 1 On 70 8.602 
Many theories have been advanced in explanation of the 
process of milk secretion, but no single theory is entirely sat- 
isfactory. [here seems to be a causative relationship, how- 
ever, between the nervous condition of the cow and the action 
of the gland. 
The amount of milk and fat secreted per hour at different 
times in the twenty-four hours is not the same. ‘Table 63 shows 
that the amount of milk secreted during the night in Period II. 
was 1.041 pounds per hour and of fat .039 pound, while the 
amount secreted per hour up tothe noon hour was 1.23 pounds 
of milk and .o74 pound of fat. 
Results from milking three times per day.—It may be stated 
that the shorter the time between milkings, the larger the 
amount of milk and fat secreted per hour. This extra amount 
secured may be due in part to the additional manipulation of 
the udder by the hand of the milker as a result of additional 
milking, but the nervous condition of the cow is, no doubt, a 
factor. 
In Table 63 is given the amount of milk and fat secreted per 
cow per hour when the cows were milked twice and three times 
a day. When milked twice per day, the amount of milk 
secreted per hour was .977 pound, and when milked three 
‘times, 1.10 pounds. When milked twice, the amount of fat 
