Table 2.

Effect of yeast supplementation on vaginal temperature, water intake, nasal lesion score, serum and hematology variables, and neutrophil functionality in feedlot heifers administered a respiratory disease challenge

	Treatment1
Item	CON	YST	SEM	P-value2
Vaginal temperature, °C	39.4	39.3	0.08	0.39
Water intake, mL/h	588	676	32.3	0.06
Serum haptoglobin, µg/dL	15,396	11,757	1,631.7	0.13
Serum cortisol, ng/mL	20.7	20.5	1.14	0.90
Lymphocytes, 103/µL	4.65	4.59	0.26	0.86
Neutrophils, 103/µL	6.39	5.37	0.39	0.07
Neutrophil:Lymphocyte	1.50	1.35	0.12	0.36
Platelets, 103/µL	438.8	399.3	30.5	0.36
Red blood cells, 106/µL	7.60	7.29	0.15	0.17
Eosonophils, 103/µL	0.18	0.17	0.03	0.72
Hematocrit, %	34.3	33.8	0.48	0.43
Hemoglobin, g/dL	11.2	11.0	0.13	0.16
Monocytes, 103/µL	1.60	1.64	0.073	0.65
Neutrophil oxidative burst intensity, GMFI3	119,898	135,696	7,227.5	0.13
PMN phagocytosis, GMFI	47,013	45,867	2,650.8	0.76
L-Selectin expression, GMFI	98,030	103,914	3,966.3	0.30

¹Heifers were fed one of two dietary treatments: 1) negative control (CON), fed a standard feedlot diet, or 2) the same standard feedlot diet with 2.5 g·heifer⁻¹·d⁻¹ live yeast and 2.5 g·heifer⁻¹·d⁻¹ yeast cell wall product (Phileo Lesaffre Animal Care, Milwaukee, WI) 31 d prior to immunological challenge (YST). Whole blood was collected every 2 h from 0 to 8 h and every 12 h from 12 to 72 h for hematology, and every 1 h from 0 to 2 h and every 12 h from 12 to 72 h for serum analysis.

²Represents treatment P-value. All treatment × time interactions were P ≥ 0.19.

³Geometric mean florescence intensity (GMFI) for neutrophil oxidative burst intensity, phagocytosis, and L-selectin expression. Whole blood was collected −72, 0, and 48 h relative to Mannheimia haemolytica immunological challenge.