Table VII.--Percentage Composition of Milk each Month of the Year; also Average Yield of Milk, and of Constituents, per Head per Day each Month, according to Rothamsted Dairy Records.
+-----------+--------------------------------+---------------------------------+ | |Average Composition of Milk each| Rothamsted Diary. | | | Month, 1884. +----------+----------------------+ | | (Dr Vieth--14,235 analyses.) | | Estimated Quantity | | | | Average | of Constituents in | | +--------+-------+------+--------+ Yield | Milk per Head per | | | | | | | of Milk | Day each Month. | | |Specific|Butter-|Solids| Total | per Head +-------+------+-------+ | |Gravity.| Fat. | not | Solids.| per Day, |Butter-|Solids| Total | | | | | Fat. | | 6 Years. | Fat. | not |Solids.| | | | | | | | | Fat. | | +-----------+--------+-------+------+--------+----------+-------+------+-------+ | | | % | % | % | lb | lb | lb | lb | | January | 1.0325 | 3.55 | 9.34 | 12.89 | 20.31* | 0.72 | 1.90 | 2.62 | | February | 1.0325 | 3.53 | 9.24 | 12.77 | 22.81 | 0.80 | 2.11 | 2.91 | | March | 1.0323 | 3.50 | 9.22 | 12.72 | 24.19 | 0.85 | 2.23 | 3.08 | | April | 1.0323 | 3.43 | 9.22 | 12.65 | 26.50 | 0.91 | 2.44 | 3.35 | | May | 1.0324 | 3.34 | 9.30 | 12.64 | 31.31 | 1.05 | 2.91 | 3.96 | | June | 1.0323 | 3.31 | 9.19 | 12.50 | 30.81 | 1.02 | 2.83 | 3.85 | | July. | 1.0319 | 3.47 | 9.13 | 12.60 | 28.00 | 0.97 | 2.56 | 3.53 | | August | 1.0318 | 3.87 | 9.08 | 12.95 | 25.00 | 0.97 | 2.27 | 3.24 | | September | 1.0321 | 4.11 | 9.17 | 13.28 | 22.94 | 0.94 | 2.11 | 3.05 | | October | 1.0324 | 4.26 | 9.27 | 13.53 | 21.00 | 0.89 | 1.95 | 2.84 | | November | 1.0324 | 4.36 | 9.29 | 13.65 | 19.19 | 0.84 | 1.78 | 2.62 | | December | 1.0326 | 4.10 | 9.29 | 13.39 | 19.31 | 0.79 | 1.79 | 2.58 | | +--------+-------+------+--------+----------+-------+------+-------+ | Mean | 1.0323 | 3.74 | 9.22 | 12.96 | 24.28 | 0.90 | 2.24 | 3.14 | +-----------+--------+-------+------+--------+----------+-------+------+-------+ * Average over five years only, as the records did not commence until February 1884.
As regards the influence of the period of the year, with its characteristic changes of food, on the quantity and composition of the milk, the first column of the second division of Table VII. shows the average yield of milk per head per day of the Rothamsted herd, averaging about 42 cows, almost exclusively Shorthorns, in each month of the year, over six years, 1884 to 1889 inclusive; and the succeeding columns show that amounts of butter-fat, of solids not fat, and of total solids in the average yield per head per day in each month of the year, calculated, not according to direct analytical determinations made at Rothamsted, but according to the results of more than 14,000 analyses made, under the superintendence of Dr Vieth, in the laboratory of the Aylesbury Dairy Company in 1884;[4] the samples analysed representing the milk from a great many different farms in each month.