This study was conducted to assess the effects of a single
transdermal administration of
flunixin meglumine (FM) in early postpartum Holstein Friesian dairy cows on milk yield, culling risk, and reproductive performance. We hypothesized that FM treatment would reduce systemic
inflammation, leading to higher milk yield, reduced culling risk, and better reproductive performance in the subsequent lactation. Holstein Friesian dairy cows [n = 500, 153 primiparous (PRIM), 347 multiparous (MULT)] from 3 farms in northeast Germany were enrolled in a prospective, randomized controlled clinical trial. Farms at risk for cows with excessive postpartum
inflammation were identified in a preliminary trial by measuring serum
haptoglobin concentrations in their fresh lactating cows. Only cows that had a eutocic birth and delivered a singleton calf alive, with no signs of milk
fever or retained fetal membranes and rectal temperature ≤40°C at first clinical examination, were included within 24 to 36 h postpartum. Treatment included a single
transdermal administration of either FM (3.33 mg/kg) or a placebo as control (CON). Milk production, milk solids,
urea, and somatic cell count were recorded monthly for 8 mo after calving. Culling risk, first-service conception risk, and days open were retrieved from the farms' herd management software. Separate models for PRIM and MULT cows were built for most parameters because of significant effects of parity and parity × treatment interaction. Energy-corrected milk yield from 8 monthly Dairy Herd Improvement-equivalent tests was slightly greater in PRIM cows treated with FM (29.51 and 30.73 ± 1.35 kg, CON vs. FM), whereas it was reduced in treated MULT cows (38.23 and 37.47 ± 1.17 kg, CON vs. FM) compared with CON. Milk fat and
protein yields were greater in FM-treated PRIM cows and lower in treated MULT cows compared with CON. Milk
urea and somatic cell count were not affected by treatment. No differences in culling risk, first-service conception risk, or days open were observed. We conclude that a single
transdermal administration of FM in early postpartum dairy cows on farms at risk for excessive postpartum
inflammation slightly increased milk, milk fat, and
milk protein yields in PRIM cows and decreased these variables in MULT cows. Neither culling risk nor fertility was affected by treatment in this study.