Effect of prenatal and lactating cow trace mineral source on Angus and Brangus calf acute phase protein response to a weaning stressor

Trace mineral (TM) source provided to gestating and lactating Angus and Brangus cows and its subsequent effect on acute phase protein (APP) response in like breeds of calves at weaning was examined during 2 yr. Treatments were inorganic (salt sulfates) or organic (Se-yeast and proteinates) TM supplementation of Co, Cu, Fe, I, Mn, Mo, Se and Zn (3 d/wk, 0.4 kg...1454 kg BW1d*cow1*d1). Delivery of TM to cows was initiated 88 ± 2 d pre-calving in year 1 and from conception to weaning of year 2. In both years, calves (year 1, n = 28/sex, 7/ treatment x breed of bulls, heifers, steers; year 2, n = 48/sex, 24/ treatment x breed of heifers, steers) were physically separated from dams at weaning (d 0) and maintained in dry-lot pens from d 0- 7, and on bahiagrass pastures from d 7-14. Calf blood samples were collected for analysis of APP including acid soluble protein (ASP), ceruloplasmin and haptoglobin on d 0, 1, 3, 7, and 14 relative to weaning. Calf was the experimental unit with PROC MIXED repeated measures within each year for analysis. Models included fixed effects of TM treatment, breed, calf sex, day relative to weaning, and interactions. Treatment did not affect any APP in year 1 (P > 0.05) or year 2 (P > 0.05). Day affected (P ≤ 0.05) all APP values within a year. In year 1, peak concentrations of all APP occurred on d 3. In year 2, peak concentrations of ASP and haptoglobin occurred on d 3, while ceruloplasmin concentrations peaked on d 7. Within a year, ASP concentrations were greater (P ≤ 0.01) in Brangus (year 1 = 83.4 ± 3.5; year 2 = 84.9 ± 2.6 mg/dL) than Angus (year 1 = 68.0 ± 3.5; year 2 = 61.7 ± 2.6 mg/dL) calves. Haptoglobin concentrations were greater (P ≤ 0.05) in year 1 and year 2 in Angus (1.8 ± 0.1 units) than Brangus (1.5 ± 0.1 units) calves within each year. For ceruloplasmin, heifers had greater (P ≤ 0.05) concentrations (15.2 ± 0.5 mg/dL) than steers (13.6 ± 0.5 mg/dL) and bulls (12.9 ± 0.5 mg/dL) in year 1; whereas in year 2, heifers (16.7 ± 0.4 mg/dL) had greater (P ≤ 0.05) ceruloplasmin concentrations than steers (15.5 ± 0.4 mg/dL). In conclusion, calf breed and sex had greater effects on APP response to weaning than TM source.