Acute heat stress brings down milk secretion in dairy cows by up-regulating the activity of the milk-borne negative feedback regulatory system

Table 1 Effect of treatments on milk yield and on the diurnal (day vs. night) variations in milk secretion

Treatments	Control (C)	SD	Cooling (D)	SD	Sun (E)	SD
Initial milk yield, Ld^-1	47.9	3.1	49.3	3.5	48.1	3.6
Night, Lh^-1	1.80¹	0.2	1.61¹	0.2	1.40¹	0.2
Day, Lh^-1	1.45²	0.3	1.40²	0.2	0.65²	0.3
Day/Night yield ratio	0.81^a	0.09	0.88^a	0.1	0.46^b	0.07
Total yield, Ld^-1	44.1	2.5	40.3	2.5	21.1	3.1
Decrease in milk Yield, %	7.9^a	1.5	18.2^b	3.6	55.1^c	5.5

Values marked by different superscript numbers are significantly different within columns; values marked with different superscript letters are significantly different within rows.

ISSN: 1472-6793