Table 1.

Circulating white blood cells (neutrophils, lymphocytes, monocytes, eosinophils, and basophils) in dairy calves with increased serotonin bioavailability.

WBC count	Treatmentsa			P-valueb
	CON	5-HTP	FLX	5-HTP vs. CON	FLX vs. CON
Neutrophils, 103/μL	3.69 ± 0.62	3.96 ± 0.67	3.69 ± 0.62	0.78	0.99
Monocytes, 103/μL	1.08 ± 0.11	1.19 ± 0.12	0.97 ± 0.11	0.51	0.48
Lymphocytes, 103/μL	4.37 ± 0.23	4.79 ± 0.24	4.79 ± 0.23	0.22	0.48
Eosinophils, 103/μL	0.06 ± 0.02	0.06 ± 0.22	0.09 ± 0.02	0.96	0.42
Basophils, 103/μL	0.01 ± 0.02	0.05 ± 0.03	0.03 ± 0.02	0.26	0.71

^aOral supplementation of milk replacer with saline (control; n = 8), fluoxetine (40 mg/d; n = 8) or 5-hydroxytryptophan (5-HTP, 90 mg/d; n = 8) to Holstein dairy calves for 10 consecutive days.

^bStatistical significance declared at P-value ≤ 0.05 and tendencies at 0.05 < P ≤ 0.10.