VARIATION IN DAILY MILK AND BUTTER PRODUCTION.

New Zealand Mail, Issue 1163, 15 June 1894, Page 5

VARIATION IN DAILY MILK AND BUTTER PRODUCTION.

The quantity of milk produced by a cow, and the quality of the milk are influenced directly by the individuality, and indirectly by the breed of the animal, Each breed is only a group of individuals of the same kind. The breeds differ from each other by certain characteristics which are preserved so long as conditions are not sufficiently strong to change them. To the distinct characteristics belongs the disposition to produce a large quantity of nlilk, or milk possessing a specific peculiarity, such as high content of butter fat and casein. Numerous observations show that with nearly all cows the milk production follows the general course of decreasing in quantity of milk and butter, and increasing in percentage of butter fat as the period of lactation progresses. By weighing and testing the milk of cows every day the writer has observed that lines representing the daily production of milk and of butter fat do not take the course of a straight line down an inclined plane, but are broken, zigzag lines. Some of the results of these observations have been represented graphically in Bulletin No. 24 of tho Illinois Experiment Station. They show the production of the cows from day to day, and aie evidence to illustrate: First, that the variation from day to day in the morning's and evening's milk considered separately was greater than in the mixed milk of the day. Second, that under exactly the same conditions cows differ from each other in the amount of this variation. A very nervous and somewhat vicious animal goes to great extremes, while a mild eyed " mooley cow " produces milk comparatively uniform in quantity and quality from day to day. Third, that the mixed milk of several cows is more uniform in amount and richness from one day to another than the milk of one cow. The record of each milking of one cow shows the general tendency to equalize the milk production by going to extremes. May 19th a cow gave 12.75 pounds of milk in the morning, and seven pounds at night. The morning milk contained 6.5 per cent, of butter fat, the night milk only two per cent. The average per milking of this cow for three months has been 9,35 pounds of milk and 3.92 per cent, of fat. In general, it was noticed that in this record when one milking was above the average in quantity and quality, the next milking went below and vice versa. During this experiment the daily quantity of milk of one cow from both milkings varied from twenty-three to seventeen pounds, the per cent, of butter fat in the daily milk from 3 to 6.1, and the pounds of butter fat in the daily milk from 0.56 to 1.29. The daily record of another cow shows a very uniform per cent, of butter fat, varying only from 2.8 to 3.4. The

same regularity is seen in the total daily production of butter fat, 0.65 to 0.42 pounds; and the record shows that the course of the line representing the pounds of butter fat gradually declines from the beginning to the end of the experiment. A decrease in the pounds of milk from day to day is also shown in the record of this cow. One of the cows is a striking example of occasional extreme variations in milk production, and, contrary to the general statement, the variation in quantity and quality coincide. That is, when she gave a small mess of milk it had a per cent, of butter fat below her average, while the largest milkings were of her richest milk. This does not hold true in the average per cow calculated from the daily records of three cows, for the reason that the milk of cow No. 1 showed just the opposite tendency from cow No. 2. Nearly every time when the milk of cow No. 1 increased in quantity it decreased in percentage of butter fat, and as the pounds of milk per day decreased the per cent, of fat in the milk increased. The milk was richer. The record of cow No. 3 on this point shows a very uniform percentage of butter fat from day to clay regardless of the quantity of milk produced. These individual characteristics may be more concisely stated thus: Cow No. 1 The richest milk is given when the quantity is small. The quantity decreases somewhat with this cow. Cow No. 2. The richest milk is given when the quantity is large. The quantity did not permanently decrease with this cow. Cow No. 3. The richness of her milk was very uniform, and changed but slightly. The quantity decreased permanently. By comparing the separate records of these cows with the average per cow calculated from the total production of the three, we find a greater irregularity in the production of a single cow. This shows that the greater the number ot cows in a dairy, the more uniform will be the production from day to day.—E. H. Farrington, Illinois Agricultural Experiment Station in the American Agriculturist.