# Effect of supplying a portion of trace mineral amino acid complexes on serum folate concentration from the dry period to early lactation

## TL;DR

This study found that replacing some inorganic trace minerals with amino acid complexes in cows' diets did not affect serum folate levels, though milk yield and other factors correlated with folate.

## Contribution

The study demonstrates that the source of trace mineral supplements does not influence serum folate concentrations in dairy cows during the transition period.

## Key findings

- Serum folate concentration was not affected by the source of trace mineral supplements.
- Milk yield and dry matter intake were positively correlated with serum folate concentration.
- Serum folate levels varied during the dry period and early lactation.

## Abstract

Summary: A total of 36 pregnant Holstein cows received either (1) an inorganic chloride trace mineral blend consisting of zinc (75 mg/kg of dry matter), manganese (65 mg/kg), and copper (10 mg/kg) as hydroxychlorides and cobalt (1 mg/kg) as carbonate or (2) partial replacement of inorganic trace minerals with amino acid complexes of trace mineral source of zinc (40 mg/kg), manganese (20 mg/kg), copper (3.5 mg/kg), and cobalt glucoheptonate (1 mg/kg) from 1 week after dry-off through 8 weeks of lactation. Serum folate concentration from week -1 to 8 relative to parturition averaged 8.39 (standard error: 0.44) ng/mL and was not affected by treatments. Milk yield, dry matter intake, serum alanine aminotransferase, and alkaline phosphatase concentrations were positively correlated with serum folate concentration, whereas serum β-hydroxybutyrate concentration tended to be negatively correlated with serum folate concentration.

Summary: A total of 36 pregnant Holstein cows received either (1) an inorganic chloride trace mineral blend consisting of zinc (75 mg/kg of dry matter), manganese (65 mg/kg), and copper (10 mg/kg) as hydroxychlorides and cobalt (1 mg/kg) as carbonate or (2) partial replacement of inorganic trace minerals with amino acid complexes of trace mineral source of zinc (40 mg/kg), manganese (20 mg/kg), copper (3.5 mg/kg), and cobalt glucoheptonate (1 mg/kg) from 1 week after dry-off through 8 weeks of lactation. Serum folate concentration from week -1 to 8 relative to parturition averaged 8.39 (standard error: 0.44) ng/mL and was not affected by treatments. Milk yield, dry matter intake, serum alanine aminotransferase, and alkaline phosphatase concentrations were positively correlated with serum folate concentration, whereas serum β-hydroxybutyrate concentration tended to be negatively correlated with serum folate concentration.

•Milk yield tended to increase by 6.6% with amino acid complexes of trace minerals.•Serum folates were not affected by the source of the trace mineral supplement.•Serum folates varied during the dry period and the onset of lactation.•Milk yield and dry matter intake were positively correlated with serum folate.

Milk yield tended to increase by 6.6% with amino acid complexes of trace minerals.

Serum folates were not affected by the source of the trace mineral supplement.

Serum folates varied during the dry period and the onset of lactation.

Milk yield and dry matter intake were positively correlated with serum folate.

Folates are required in one-carbon metabolism and DNA methylation. During the transition period, these roles are particularly important for the final stages of fetal development and the onset of lactation. The objective of this retrospective study was to assess plasma folate concentration when a portion of dietary inorganic chloride trace minerals (ITM) and cobalt (Co) carbonate was replaced by AA complexes of trace minerals (AATM) and Co glucoheptonate during the transition period. Relationships between serum folate concentration and health biomarkers were also evaluated. With dietary trace mineral concentrations being the same between treatments, a total of 36 Holstein multiparous cows were randomly assigned based on their parity number and previous 305-d mature equivalent milk production to either (1) an ITM blend consisting of zinc (75 mg/kg DM), manganese (65 mg/kg), and copper (10 mg/kg) as hydroxychlorides, and cobalt (1 mg/kg) as carbonate (ITM) or (2) partial replacement of ITM with AATM of Zn (40 mg/kg), Mn (20 mg/kg), Cu (3.5 mg/kg), and Co glucoheptonate (1 mg/kg; AATM, Availa-Dairy, Zinpro Corp.) from 1 wk after dry-off through 8 wk of lactation. Milk yields were recorded at each milking. Blood samples were taken at wk −8 (before treatment administration), −1, 1, 2, and 8 relative to parturition for serum folate analysis. Serum folate concentration from wk −1 to 8 relative to parturition averaged 8.39 (SE: 0.44) ng/mL and was not affected by treatments. Regardless of treatments, serum folate concentration significantly decreased from wk −8 to −1, plateaued from wk −1 to 2 relative to parturition, and then significantly increased through wk 8 of lactation. Milk yield, DMI, serum alanine aminotransferase, and alkaline phosphatase concentrations were positively correlated with serum folate concentration, whereas serum BHB concentration tended to be negatively correlated with serum folate concentration. In conclusion, in the current study, the source of the trace mineral supplement fed during the dry period and early lactation did not have an impact on serum folate concentrations.