title: Patterns of circulating serotonin and related metabolites in multiparous dairy cows in the peripartum period.
abstract: Dairy cows are challenged to maintain Ca and glucose homeostasis during the transition period. Serotonin (5-HT) is a monoamine that modulates Ca and glucose homeostasis in rodents. Serotonin is positively correlated with Ca and glucose status in dairy cows on d 1 of lactation. However, the pattern of circulating concentrations of 5-HT over the course of a 305-d lactation is unknown. In this observational, longitudinal study, we examined the metabolite patterns of 5-HT, Ca, glucose, parathyroid hormone-related protein, and β-hydroxybutyrate on 2 commercial dairy farms in south-central Wisconsin. Cows sampled on farm 1 were multiparous Jersey cows (n=30) that calved within a 23-d period; cows on farm 2 were multiparous Holstein cows (n=35) that calved within a 20-d period. Blood samples were collected daily between d -5 and d 10 relative to parturition and on d 30, 60, 90, 150, and 300 of lactation. Farms 1 and 2 were analyzed individually because of the presence of a farm effect in the initial analysis; a time effect was present on both farms. Concentrations of 5-HT decreased near parturition compared with prepartum by 57.9 and 29.5% on farm 1 and 2, respectively. Transition period 5-HT nadirs were observed on d 1 on farm 1, and on d 1 and 9 on farm 2. Serotonin recovered to prepartum concentrations by d 5 on farm 1. On farm 2, 5-HT recovered to prepartum concentrations by d 4, with a subsequent decrease of 34.6% on d 9 to a level similar to that observed on d 1. Furthermore, 5-HT increased markedly in cows on both farms near peak lactation (d 60, 90, and 150) and decreased on d 300. Compared with prepartum concentrations, Ca decreased by 34.2 and 11.2% on farms 1 and 2, respectively. Circulating total Ca nadir was observed on d 1 on both farms. Circulating 5-HT and circulating Ca were positively correlated during the early lactation period (d 1 to 5 and d 6 to 10) on farm 1 (r=0.31 and r=0.22, respectively) and d 6 to 10 on farm 2 (r=0.16). Circulating 5-HT and glucose were negatively correlated during the early lactation period (d 1 to 5) on farm 1 (r=-0.21) and during mid-lactation (d 30 to 150) on farm 2 (r=-0.26). Milk 5-HT and milk total Ca were positively correlated on farm 2 (r=0.34). These results demonstrate that 5-HT concentrations change dynamically throughout the transition period, with a pattern similar to that of total Ca concentrations. Further research using controlled experiments should be aimed at discerning the association between 5-HT and Ca and between 5-HT and glucose in dairy cows.
authors.affiliation: Department of Dairy Science, University of Wisconsin-Madison, Madison 53706.
authors.forename: S A E
authors.initials: SA
authors.lastname: Moore
authors.affiliation: Department of Dairy Science, University of Wisconsin-Madison, Madison 53706.
authors.forename: J
authors.initials: J
authors.lastname: Laporta
authors.affiliation: Department of Animal Science, University of Wisconsin-Madison, Madison 53706.
authors.forename: T D
authors.initials: TD
authors.lastname: Crenshaw
authors.affiliation: Department of Dairy Science, University of Wisconsin-Madison, Madison 53706. Electronic address: llhernandez@wisc.edu.
authors.forename: L L
authors.initials: LL
authors.lastname: Hernandez
mesh_terms: D020155:3-Hydroxybutyric Acid / Q000097:blood; D000818:Animals; D001786:Blood Glucose / Q000032:analysis; D002118:Calcium / Q000097:blood; D002417:Cattle / Q000097:blood*; D005260:Female; D007774:Lactation / Q000097:blood; D008137:Longitudinal Studies; D008892:Milk; D044162:Parathyroid Hormone-Related Protein / Q000097:blood; D010298:Parity; D036801:Parturition / Q000097:blood; D058725:Peripartum Period / Q000097:blood*; D011247:Pregnancy; D012701:Serotonin / Q000097:blood*; D014922:Wisconsin
chemical_list: D001786:Blood Glucose; D044162:Parathyroid Hormone-Related Protein; D012701:Serotonin; D002118:Calcium; D020155:3-Hydroxybutyric Acid
keywords: calcium; hypocalcemia; lactation; serotonin