Hepatic one-carbon metabolism enzyme activities and intermediate metabolites are altered by prepartum body condition score and plane of nutrition in grazing Holstein dairy cows.

Precalving feeding level and body condition score (BCS) alter postcalving energy balance and oxidant status of dairy cows. We hypothesized that the reported benefits of a controlled restriction precalving depend on precalving BCS. The objective was to identify alterations in activity and intermediates of the hepatic one-carbon metabolism, transsulfuration, and tricarboxylic acid pathways. Twenty-eight pregnant and nonlactating grazing dairy cows of mixed age and breed (Friesian, Friesian × Jersey) were randomly allocated to 1 of 4 treatment groups in a 2 × 2 factorial design: 2 prepartum BCS categories [4.0 (thin, BCS4) and 5.0 (optimal, BCS5); 10-point scale], by managing cows in late lactation to achieve the 2 groups at dry-off, and 2 levels of energy intake during the 3 wk preceding calving (75 or 125% of estimated requirements), obtained via allowance (m

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The Authors. Published by FASS Inc. and Elsevier Inc. on behalf of the American Dairy Science Association®. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).