The objective of this study was to assess the effect of a commercial immune stimulant (Amplimune, NovaVive Inc., Napanee, Canada) on the peripartum dynamics of circulant neutrophils (NEU), lymphocytes (LYM), and monocytes (MON). Holstein cows (n = 34) were randomly assigned into 1 of 2 treatments (Trt): (1) Amplimune (AMP; n = 16), receiving a 5 mL subcutaneous (s.c.) dose of Amplimune at enrollment (7 ± 3 d before calving) and at calving (1 ± 1 DIM); and (2) Control (Con; n = 18), receiving 5 mL s.c. of saline solution at the same time points. White cell counts were log-transformed and examined using repeated measures analysis (PROC MIXED), with models including Trt, parity, occurrence of metritis (MET), sampling point (Time; 1 = enrollment; 2 = 2 d after enrollment; 3 = calving; 4 = 2 DIM; 5 = 7 DIM; and 6 = 14 DIM) and the interaction Trt × Time. LSM (95%CI) for NEU, LYM, and MON at different sampling points and by Trt are presented in Table 1. The effect of the interaction Trt × Time was not significant for NEU (P = 0.28), LYM (P = 0.84), and MON (P = 0.49). In conclusion, no treatment effect was determined for NEU, LYM and MON counts. Table 1 (Abstr. 348). Means and confidence intervals of circulant cell counts (Log cell/mL)

	Sampling time							P-value
1	2	3	4	5	6	Trt	Time	Trt × Time
NEU
Con	3.57(3.31–3.82)	3.58(3.33–3.83)	3.28(3.02–3.53)	3.47(3.22–3.73)	3.38(3.12–3.63)	3.43(3.17–3.68)		0.65	<0.001	0.28
Trt	3.60(3.39–3.81)	3.6(3.39–3.81)	3.49(3.28–3.7)	3.40(3.20–3.60)	3.35(3.14–3.56)	3.45(3.24–3.67)
LYM
Con	3.84(3.63–4.1)	3.82(3.61–4.00)	3.78(3.56–4.00)	3.78(3.56–4.00)	3.76(3.55–3.98)	3.77(3.56–4.00)		0.4	0.02	0.84
Trt	3.70(3.52–3.9)	3.67(3.48–3.85)	3.64(3.45–3.82)	3.65(3.46–3.83)	3.63(3.45–3.82)	3.61(3.42–3.8)
MON
Con	2.70(2.52–2.89)	2.68(2.49–2.86)	2.83(2.64–3.02)	3.02(2.83–3.2)	2.85(3.66–3.04)	2.76(2.57–2.94)		0.33	<0.001	0.50
Trt	2.69(2.54–2.85)	2.78(2.62–2.93)	2.79(2.64–2.95)	3.03(2.87–3.18)	2.83(2.67–2.98)	2.71(2.55–2.86)