Effect of dose rate and timing of administration of pegbovigrastim on white blood cell responses in grazing dairy cows.

Transition dairy cows experience a decline in immune function that increases the risk of peripartum disease. One strategy to improve peripartum immune function involves the use of a commercially available cytokine: bovine granulocyte-colony stimulating factor, with the addition of polyethylene glycol to increase duration of effectiveness. Treatment with Imrestor (15 mg pegbovigrastim; Elanco) one week before expected calving date (d -7) and again on the day of calving (d 0) was previously reported to increase the neutrophil number and improve neutrophil function; as a result, the incidence of clinical mastitis was reduced. We conducted 2 experiments over consecutive years to investigate the effect of a lower dose rate (half or quarter dose rate) of Imrestor in grazing dairy cattle and reduced administration frequency: one dose instead of the recommended 2. White blood cell counts were measured to determine changes in relative cell populations in response to treatment. Neutrophil function was assessed by measuring myeloperoxidase activity. Imrestor treatment increased the numbers of neutrophils, band cells, lymphocytes, and monocytes until 14 d postcalving in a dose-dependent manner; it also increased neutrophil myeloperoxidase activity. One dose of Imrestor increased white blood cell counts and myeloperoxidase activity, but the timing, degree, and duration of the response were different relative to the recommended 2 doses and were also dependent upon when Imrestor treatment was given. One dose at d -7 relative to expected calving date did not have a lasting effect postcalving, whereas one dose only on d 0 caused a delayed effect relative to cows that received 2 doses. There was no effect of Imrestor on milk yield or on blood indicators of transition cow health. A lower dose rate of Imrestor or a single dose of Imrestor on the day of calving may be sufficient to improve neutrophil function during the early postpartum in grazing dairy cows. Large-scale field studies are required to determine whether the smaller response from lower dose rates or the timing of the immunological response to drug delivery affect animal health in early lactation.

Investigation of the effect of pegbovigrastim on some periparturient immune disorders and performance in Mexican dairy herds.

This study analyzed the efficacy of pegbovigrastim (Imrestor, Elanco Animal Health, Greenfield, IN) on some health and production parameters in lactating dairy cows. Primiparous and multiparous Holsteins from 17 Mexican dairy herds (n = 10,238) were included in this study, which was conducted in 2015. Treated cows (n = 5,025) received Imrestor approximately 7 d before expected calving and again within 24 h after calving; control cows (n = 5,213) did not receive a placebo. Clinical mastitis (MAS; 0 to 30 DIM), retained placenta (RP), and clinical metritis (MET; 0 to 21 DIM) occurrences were recorded, as well as the number of medication days, medical treatments needed, and the number of days that milk was discarded due to medication administered for disease. Milk yield was measured from calving until 120 d in milk. Imrestor reduced the incidence of MAS by 25%, and the odds ratio of having mastitis in the first 30 d in milk was 35% greater for control cows than for Imrestor cows. Imrestor treatment reduced the number of medical treatments required for MAS by 6%, and less milk was discarded due to medication for MAS as a result of the Imrestor treatment. The incidence of RP was reduced by 4.15% with Imrestor and the odds of cows having RP were 4.6% greater for control than Imrestor treatments, but they did not differ. The MET incidence was increased by 17.1% with Imrestor. The use of Imrestor around parturition increased by 5.8% the odds of inseminating cows during the first 100 d after calving. Imrestor-treated multiparous cows with MAS produced 2.1 kg/d more milk than control cows with MAS during the first 30 d of their lactation. Imrestor-treated multiparous cows with MET produced 2.3 kg/d more milk than MET control cows during the first 120 d of their lactation. We conclude that Imrestor can help the dairy cow cope with immune periparturient disorders and can increase the milk yield of dairy cows due to a healthier transition, despite a reported increase in the incidence of MET.

Evaluation of production parameters and health of dairy cows treated with pegbovigrastim in the transition period.

The aim of this study was to evaluate the effects of pegbovigrastim injection (Imrestor, Elanco Animal Health, Greenfield, IN) on production parameters and postpartum disease occurrence (retained placenta, metritis, displaced abomasum, and clinical mastitis) in dairy cows. Study cows (n = 270) were blocked by parity group (multiparous or primiparous) and randomly assigned to control (CON, n = 144) or pegbovigrastim treatment (IMR, n = 126). Ten ± 4 days before expected calving and again at calving, IMR cows received 2.7 mL of Imrestor and CON cows received 2.7 mL of 0.9 % saline. Milk yield, fat, protein, lactose, solids nonfat (SNF) percent, and somatic cell count (SCC), body condition, hygiene, and lameness were evaluated weekly. Animals were evaluated for metritis twice weekly through rectal temperature, palpation, and uterine discharge evaluation until 30 days in milk. Farm personnel recorded other postpartum diseases. The MIXED procedure of SAS was used to evaluate milk composition and milk yields were analyzed as repeated measures in time with block, treatment, calving month, and lactation week included in mixed models. The GLIMMIX procedure was used to evaluate mastitis and metritis occurrence. Variables entered a model if P ≤ 0.10 when screened individually. Variables with P ≤ 0.10 were kept in the final model. Milk yield, fat, protein, lactose, SNF, and log of SCC were not significantly affected by treatment. Clinical mastitis occurrence did not differ between treatments, but only 17 cases were detected. Compared to CON, IMR treated cows had increased clinical metritis incidence, and were 2.46 times more likely to develop the disease. No difference was observed on puerperal metritis ocurrence. Cows given pegbovigrastim injections had increased odds of developing clinical signs of metritis, but no negative effects on milk production or composition were observed.