Reducing the incidence of acute puerperal metritis in primiparous cows by application of pegbovigrastim in a Holstein dairy herd

In dairy cows, immunosuppression occurs frequently during the periparturient period and is characterised by transient neutropenia and impaired polymorphonuclear neutrophil function. As a consequence, postpartum cows are more susceptible to production-related diseases such as mastitis, retained foetal membranes and metritis. Recently, it has been shown that a double injection with recombinant bovine granulocyte colony-stimulating factor covalently bound to polyethylene glycol (PEG rbG-CSF) increased polymorphonuclear neutrophil number and the exocytosis of myeloperoxidase by stimulating polymorphonuclear neutrophil, which also played a role in innate uterine immune defence. The aim of this randomised clinical study was to investigate the effects of two periparturient PEG rbG-CSF injections (IMR; Imrestor^TM, Elanco Animal Health, Bad Homburg/Germany) on the incidence of acute puerperal metritis, number of antibiotic doses required for treatment of acute puerperal metritis as well as parameters of milking performance (i.e., milk yield, milk fat, milk protein, and somatic cell count on the first dairy herd improvement test day) in primiparous cows within a dairy herd with an elevated incidence of acute puerperal metritis. In total, 169 heavily pregnant heifers were randomly assigned to the treatment group (IMR: n = 82) who received 15 mg PEG rbG-CSF subcutaneously 10 ± 3 days before the anticipated calving date and within 24 hours after calving, or to the untreated control group (Co: n = 87). In total, data from 157 animals (IMR: n = 75, Co: n = 82) were analysed. Administration of PEG rbG-CSF reduced the incidence of acute puerperal metritis in primiparous cows significantly (IMR: 22.7%, Co: 43.9%, P = 0.003; relative reduction: 48.3%). Moreover, the number of antibiotic doses per calving required for treatment of acute puerperal metritis was significantly lower in the pegbovigastrim group (IMR: 0.32 ± 0.66, Co: 0.59 ± 0.75, P = 0.005). No significant differences regarding incidence of clinical mastitis, milk production or milk composition were observed. These results suggest that further research should be performed to identify herd- and animal-specific factors that can be predictors of the beneficial effects of pegbovigrastim in preventing uterine diseases.