Table 1.

Changes in number of milking cows per Danish herd and their individual contribution to the bulk milk

Parameter		2003			2010
	80 %	83 %	88 %	80 %	83 %	88 %
a	59 (463)	62 (480)	65 (509)	101 (948)	105 (984)	111 (1043)
b	25 (28)	25 (27)	23 (26)	29 (32)	28 (31)	26 (29)
c	1.70 (0.22)	1.61 (0.21)	1.54 (0.20)	0.99 (0.11)	0.95 (0.10)	0.90 (0.10)

Parameters a, b and c were estimated based on data from the Danish diary industry, assuming that usually 17 % of the cows in a herd are dry and not contributing to the bulk milk. Therefore, usually 83 % of the cows are lactating, 80 % is the minimum and 88 % is the maximum proportion of lactating cows. a) Number of lactating cows/herd/day according to median herd size in 2003 (74 cows) and 2010 (127 cows), b) amount of milk produced (kg) per cow/day and c) daily contribution of a single cow to the bulk milk (in %). The estimates for the largest herds in 2003 (579 cows) and 2010 (1185 cows) are shown in brackets