At 12 h after hatch, an interaction between EST and CO2 was found for pCO2 (P = 0.02), bicarbonate (P =0.05), glucose (P < 0.001), and calcium (P = 0.0002;Table 3). At low EST, pCO2 was higher at high compared with low CO2 (Δ = 8.6 mmHg), bicarbonate was higher at high compared with low CO2 (Δ = 3.4 mmol/L), and calcium was higher at high compared with low CO2 (Δ = 0.22 mmol/L)