Circulating parathyroid hormone and serotonin in multiparous cows with differing postparturient serum calcium...

Area of Science:

• Veterinary Medicine
• Animal Science
• Endocrinology

Background:

• Multiparous dairy cows frequently experience subclinical hypocalcemia (SCH) postpartum.
• Dynamics of SCH influence cow health and milk production outcomes.
• Understanding calcium (Ca) homeostasis mediators is crucial for managing SCH.

Purpose of the Study:

• To investigate differences in Ca homeostasis mediators among dairy cows with varying SCH dynamics.
• To classify cows into normocalcemic (NC), transient SCH (tSCH), delayed SCH (dSCH), and persistent SCH (pSCH) groups.
• To analyze serum total calcium (tCa), parathyroid hormone (PTH), and serotonin levels.

Main Methods:

• Prospective cohort study of 89 multiparous Holstein cows.
• Classification into four SCH groups based on serum tCa at 1 and 4 days in milk (DIM).
• Blood sampling from prepartum to 10 DIM, analyzing tCa, PTH, and serotonin; statistical analysis using repeated measures ANOVA.

Main Results:

• Postpartum tCa varied significantly across SCH groups, with pSCH cows exhibiting the lowest levels.
• Mean postpartum PTH concentrations were numerically higher in cows with dSCH and pSCH compared to NC and tSCH.
• Serotonin levels were similar across groups and showed a cyclical pattern.

Conclusions:

• Hypothesized differences in postpartum PTH between SCH groups were observed, suggesting potential Ca homeostasis disruption in dSCH and pSCH cows.
• Further research is needed to confirm the role of PTH in different SCH dynamics.
• Understanding these differences can inform prevention, management, and treatment strategies for SCH.