Cortisol levels in skimmed milk during the first 22 weeks of lactation and response to short-term metabolic stress and lameness in dairy cows

Table 1 Mean cortisol in skimmed milk (LSM) at three days before, three days of and three days after feed restriction (70 % of previous ad libitum intake) in early and mid-lactation

Relative to FR	FR in early lactation (n = 24)		FR in mid-lactation (n = 22)		RSD^a
Relative to FR	DIM	Cortisol, nmol/L	DIM	Cortisol, nmol/L
Before	23	4.67	138	5.17	1.86
	24	3.85	139	4.74
	25	4.24	140	4.76
During	26	4.14	141	4.55
	27	3.88	142	3.70
	28	4.51	143	3.91
After	29	4.25	144	3.76
	30	4.68	145	4.96
	31	4.38	146	5.09

FR feed restriction, DIM day in milk, day relative to parturition, RSD residual standard deviation, ECM energy corrected milk yield
^aResidual standard deviation was calculated by extracting the square root of the residual

ISSN: 2049-1891