Comparative Analysis of Whole Blood Ionised Calcium, Lactate and Chloride Concentrations by Gem Premier 3000 and Edan I15 Vet and the Effect of Parity and Postpartum Blood Collection Time on Blood Calcium Status in Holstein With and Without Subclinical Hypocalcemia - Part 1

Abstract Lactating Holstein (n=125) were enrolled randomly for the coccygeal whole blood analysis by blood gas devices GEM Premier 3000 (GEM) and Edan i15 Vet (EDAN) between calving to postpartum day 3 (G1) and postpartum day 4 to 27 (G2). Blood pH, ionised calcium (ICA7.4) and lactate analysis were significantly correlated between GEM and EDAN (r=0.86, 0.94, 0.87 respectively). The bias for ICA7.4, lactate and pH analysis was -0.054, -0.344 mmol/L and +0.009 respectively. ICA7.4 was correlated negatively with parity and chloride, but positively with lactate. The averages of ICA7.4 and serum total calcium (TC) was significantly lower in G1 than G2. Chloride and lactate were significantly higher in G1 than G2. Subclinical hypocalcemia prevalence (SCH) (serum TC<2.15 mmol/L, as reference) was 52.9% in G1 and 21.1% in G2. Cows with SCH had frequently over 50% ICA7.4/TC ratio. Sensitivity analysis provided a sensitivity of 57.4% for ICA7.4 cut-points of 1.02 (GEM) and 1.05 (EDAN) mmol/L to detect SCH based on reference serum TC. Primiparous (PRP) with and without SCH in G1 had significantly higher ICA7.4 than multiparous (MUL). Cows with SCH had significantly higher chloride in G1 than G2. MUL had significantly higher lactate and chloride in G1 than G2. Conclusively, ICA7.4 and pH analysis between GEM and EDAN were correlated well with acceptable biases, but high differences occurred in lactate analysis. MUL was at risk in G1 due to lower ICA7.4 and TC over PRP. Higher ICA7.4 of PRP can reduce the risk and frequency of clinical hypocalcemia. SCH correlated negatively with Cl concentration in G1, but not lactate.