Influence of subclinical hypocalcemia on plasma biochemical parameters, liver histologic changes, and common postpartum diseases in dairy cows
Abstract
We hypothesized that cows with subclinical hypocalcemia at calving would have greater elevations in liver associated biochemical parameters and non-esterified fatty acid (NEFA) concentrations compared to normocalcemic cows. One hundred multiparous Holstein cows were assigned to one of two groups 1) normocalcemic (n=49; ionized calcium [iCa] ! 1.0 mmol/L) or 2) hypocalcemic (n=51; [iCa] [less than 1.0 mmol/L) based on whole blood [iCa] on the day of calving. Blood samples were collected from all cows for measurement of [iCa], NEFA concentrations, and plasma chemistry profiles at days -14, 0 (calving), 3, 7, 14, 21, and 35. On day 0, hypocalcemic cows had lower [iCa] than normocalcemic cows (P [less than] 0.001) and lower total plasma Ca (P [less than] 0.001). Hypocalcemic cows had lower plasma phosphorus concentrations on days 0 (P = 0.002), 7 (P = 0.05), 14 (P = 0.03), and 21 (P = 0.04). Hypocalcemic cows had higher NEFA concentrations on days 0 (P = 0.01) and 21 (P = 0.02). Hypocalcemic cows also tended to have higher NEFA concentrations on day 14 (P = 0.12). Hypocalcemic cows had more lipid in the hepatocytes on day 35 (P = 0.0008). No differences were detected between groups for total or direct bilirubin concentration, gamma glutamyl transferase or aspartate aminotransferase activity (P [greater than] 0.05). These data provide evidence of an association between calcium status at calving, fat mobilization, and liver lipid infiltration.
Degree
M.S.
Thesis Department
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OpenAccess.
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