(pegbovigrastim injection),

the first and only immune restorative for periparturient cows and heifers.

Available only by prescription, Imrestor reductes the incidence of clinical mastitis by 28% in the first 30 days of lactation in periparturient dairy cows and periparturient replacement dairy heifers.

Imrestor is a protein that helps restore the integrity of a cow’s innate immune system during the time when she experiences periparturient immune suppression. By reducing the incidence of mastitis around calving, Imrestor is the helping hand a dairy farm needs to help protect her potential.
Click below to learn more about how Imrestor helps:


the function and increase the number of neutrophils when periparturient immune suppression leaves her vulnerable to infection


the incidence of clinical mastitis around calving by 28%


her potential and the well-being of the entire dairy, as well as minimize the frustration of treating mastitis, with a product that is proven safe and effective for your herd

Imrestor is administered with 2 subcutaneous injections

Injection #1: 7 days* before the anticipated date of calving

Injection #2: within 24 hours after calving. Each cow should always receive both doses of Imrestor.

*4-10 days to accommodate management schedules.
See label for complete dosage and administration instructions.

Helps Restore Innate Immune Function

Imrestor® (pegbovigrastim injection) helps restore the function and increase the number of neutrophils at calving

Neutrophils, a key weapon of the immune system,1 are the primary type of white blood cell that recognizes and kills harmful bacteria. An integral part of the innate immune system, neutrophils respond to and destroy invading bacteria before disease can occur.

Restore Neutrophil Function

Myeloperoxidase (MPO) activity plays a critical role in how neutrophils kill bacteria and is a widely used measure of neutrophil function.

Neutrophil Numbers


Effectiveness of Imrestor is not specific to pathogen type3

Instead of fighting mastitis infections one pathogen at a time, Imrestor helps restore a cow’s ability to fight a broad range of the pathogens typically found on commercial dairy operations—including gram-negative and gram-positive bacteria.

Imrestor is not a hormone, not an antibiotic, and not a vaccine

How does Imrestor work?

Watch our mode of action video to learn how Imrestor helps restore the function and increase the number of neutrophils.

To learn more about how Imrestor can help restore innate immune function around calving, contact your veterinarian or Elanco representative.

Helps Reduce Clinical Mastitis

Imrestor® (pegbovigrastim injection) is effective at reducing the incidence of clinical mastitis around calving by 28 percent

  • Studies were conducted for FDA approval at 5 commercial dairy trial sites, across a variety of climates and management styles, in both Holstein and Jersey animals
  • Each trial site had a mastitis dry off protocol that included one or more of the following: a mastitis vaccine, dry cow treatment, or teat sealant
  • The benefits of Imrestor were in addition to existing good management practices already in place at each trial site 
28% Reduction of Clinical Mastitis
  Number of cows enrolled in study Cases of clinical mastitis / Number of cows completed study* Treatment failure rate
Control 401 85/338 25%
Imrestor 400 60/331 18%
% Reduction   28%

*132 cows removed from the study for non-mastitis reasons.
†P < 0.03.

Safe for cows

Imrestor showed no clinically relevant effects on somatic cell count, milk components, calf health, or daily milk production. It also had no negative effects on reproduction in pivotal trials.4

Want more details?

Download the clinical trial report for complete information on how Imrestor helps reduce the incidence of clinical mastitis around calving.

Download the Report

To learn more about what a significant reduction in clinical mastitis could mean to you, contact your veterinarian or Elanco representative.

Helps Protect Her Potential

The effects of clinical mastitis can be felt throughout a dairy operation

Conception Rate

Reproductive performance

Other research has shown that mastitis can reduce a cow’s conception rate by up to 23%5

Well Being

Cow well-being

Other research has demonstrated that the occurrence of mastitis in one lactation results in a 4x increase in the chance of mastitis in subsequent lactations6

Lost Productivity

Lactation potential

Other research has estimated over 2500 pounds of production could be lost throughout lactation for each case of early lactation clinical mastitis7

Imrestor® (pegbovigrastim injection) Leads to Fewer Cases of Clinical Mastitis on a Dairy

A 28% reduction in clinical mastitis in periparturient cows and heifers decreases the need for antibiotics and other treatments, reducing the amount of discarded milk during the first 30 days of lactation.

No meat or milk withdrawal times or residues to worry about*

By protecting your cows proactively against the pathogens that cause clinical mastitis, Imrestor helps minimize the long-term effect the disease can have on a dairy.

*When used according to label directions.

To find out how Imrestor can help protect the potential of your herd, contact your veterinarian or Elanco representative.

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To help protect the whole herd with Imrestor as part of an ongoing herd health management program, contact your veterinarian or Elanco Representative.

To speak to a representative at the Elanco Customer Care Center, call 1-800-233-2999.


Mode of Action

Click the video to learn more about how Imrestor helps restore the function and increase the number of neutrophils.

Video-Meadow Lane
Meadow Lane Dairy

Click the video to hear more about how one dairy producer implemented Imrestor in his herd.

Video-Union Go
Union Go Dairy

Click the video to hear more about how one dairy producer has used innovation to reduce antibiotic use on his dairy.

Video-Elanco One Health
Elanco One Health

Click the video to learn more about how Imrestor supports One Health, the foundation for enriching lives.



Not for use in humans. Keep out of reach of children. In case of accidental self-injection, wash the site of injection thoroughly with clean running water. Foreign proteins such as pegbovigrastim have the potential to cause anaphylactic-type reactions. No withdrawal period or milk discard time is required when used according to the labeling. Do not use Imrestor to treat cows with clinical mastitis because effectiveness has not been demonstrated for this use. Some cases of hypersensitivity-type reactions have been observed in studies outside the United States within five minutes to two hours, occurring most often after the first administration of Imrestor. Clinical signs may include elevated respiratory rate, dyspnea, urticaria, sweating, dependent edema, swollen mucous membranes, and/or hypersalivation, and, rarely, death. These reactions resolve within hours of onset with or without therapeutic intervention and have not been shown to reoccur with subsequent injections of Imrestor. Abomasal ulcerations/erosions were observed in the Margin of Safety studies; it was concluded that these findings were not clinically relevant. For product label, including complete safety and use information, click here.


  1. Tizard IR. Veterinary Immunology. 8th ed. St Louis, MO: Elsevier Inc; 2009:28-40.
  2. Adapted from Kimura K. Effect of recombinant bovine granulocyte colony-stimulating factor covalently bound to polyethylene glycol injection on neutrophil number and function in periparturient dairy cows. J Dairy Sci. 2014;97:1-10.
  3. Elanco Animal Health. Data on file.
  4. Elanco Animal Health. Data on file.
  5. Santos JEP. Effect of timing of first clinical mastitis occurrence on lactational and reproductive performance of Holstein dairy cows. Anim Reprod. 2004;80:31-45.
  6. Pantoja JC, Hulland C, Ruegg PL. Somatic cell count status across the dry period as a risk factor for the development of clinical mastitis in the subsequent lactation. J Dairy Sci. 2009;92:139-148.
  7. Wilson DJ, González RN, Hertl J, et al. Effect of clinical mastitis on the lactation curve: A mixed model estimation using daily milk weights. J Dairy Sci. 2004;87:2073-2084.