74 EXPERIMENT STATION RECORD. 



NA'as 124 eggs. The average second year production was exactly the same as 

 the first, while the average of the third year was only one dozen less. 



The normal variation in first year flock averages of this strain of fowls is 

 apparently between 100 and 160 eggs, the second year between 105 and 140, 

 and the third year between 100 and 130. After that the average for all ages 

 has been very close to 90 eggs per year. There appears to be a fairly definite 

 potential laying capacity for a flock of this strain of fowls which finds expres- 

 sion in the first three years. The total production of a flock for the first three 

 years appears to be the same regardless of whether the first year record was 

 extremely high, extremely low, or medium in amount. Apparently nearly all 

 of the longer-lived hens of a flock will lay over 500 eggs ; the majority of them 

 will lay over GOO or 700, while some individual records running from 800 up to 

 nearly 1,000 eggs may be expected. 



Considering only hens that have made three or more years' records, the uni- 

 formity of the three-year averages is still more striking. The difference be- 

 tween the highest and lowest records in a flock has averaged 170 for the first 

 year and 182 for the second year. In flocks making low first year records the 

 second and third year records were high and there was little difference in pro- 

 duction in these two years between the high layers and the low layers of the 

 fij-st year. In the flocks making high first year records the second and third 

 years' records were low but the higher layers of the first year continued to be 

 the highest producers of these fiocks for these years. The 10 hens making the 

 highest second year's record gave a higher three-year total than the 10 making 

 the highest first-year record. More hens have maxle their highest year's record 

 sfter the first year than during that year. Three hens made their highest 

 record the fifth year. Nearly all the hens in these flocks whose total produc- 

 tion has been extremely high have made low or only medium first-year records. 



From these studies it appears that the three-year average is the most reliable 

 index of the value of a given individual. 



DAIRY FARMING— DAIRYING. 



The comparative efficiency for milk production of the nitrogen of alfalfa 

 hay and the corn grain. — Preliminary observations on the effect of diuresis 

 on milk secretion, E. B. Hart and G. C. Humphrey (Jour. Biol. Chcm., 19 

 (lOl-i), No. 1, pp. 127-140, figs. 3). — In two experiments comparing the efficiency 

 for milk production of the nitrogen of alfalfa hay and of the corn grain. Hol- 

 stein cows in full milk were fed by the reversal method for periods of four 

 weeks the two rations, (1) corn-meal, gluten feed, and corn stover, and (2) 

 alfalfa hay and cornstarch, in such quantities that the total consumption of 

 air-dried matter, total therms, total nitrogen, and nutritive ratios were approxi- 

 mately alike in tlie two rations. In the first experiment the digestive nitrogen 

 in the two rations was closely comparable while in the second experiment the 

 nitrogen intake was kept at a higher level in the alfalfa ration. Records were 

 taken of the nitrogen balance, milk nitrogen, and urine output. 



" The data indicate that on the plane of intake used the nitrogen of alfalfa 

 hay is as effective for milk protein building as that of the corn kernel. The acid 

 amid nitrogen of alfalfa is very low in amount, constituting about 1 per cent 

 of the total nitrogen, while the amino acid nitrogen makes about 10 per cent 

 of the total nitrogen. It is well established that amino nitrogen has nutritive 

 value and that of alfalfa hay is probably not an exception. Our experiments 

 give no indication of the value of the acid amid nitrogen. The real nutritive 

 value of the nitrogen of roughages should rest upon the nature of the total amino 

 acid content derived from more complex proteins and preexisting free amino 



