The Thai Journal of Veterinary Medicine


The objective of this study was to define the coefficients for the calculation of standard milk production and the average daily milk production for the whole lactation, from the milk production measured on one test day. Individual milk production data from a farm, with an average of 45 milking cows, in the Khonkaen province, were collected daily over a period of one year. Data from healthy cows, in lactations 1 to 6, were used. The lactation period was divided into 13 separate periods: days 0-15, 16-30, and every 30-day period after that. Parity was divided into first parity and parities 2-6. A general linear mixed model was used to analyze the data by the calculation of least square means (Lsmean) of the average milk production in each lactation period, within each parity. Standard milk production was calculated by dividing the 300-day milk production total by 300. Each coefficient for the lactation periods, separated by parity, was calculated by dividing it’s Lsmeans by the standard milk production. The use of these coefficients can help farmers and practitioners to compare production efficiencies between cows and between herds.

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