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Imrestor® (pegbovigrastim injection)

An innovative way to reduce clinical mastitis and help protect her potential.
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Rumensin® (monensin, USP)

The extra energy a dairy farm needs.
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Keto-Test®

A cow-side milk test that indicates the presence of subclinical ketosis

Rumensin Logo
Rumensin® (monensin, USP)

The extra energy a dairy farm needs.

Why is extra energy important?


Approved for use in lactating dairy cows

Rumensin gives cows a boost of extra energy* that can increase their milk production efficiency.1† Rumensin is the only FDA-approved feed ingredient for lactating and dry cows that increases milk production efficiency by delivering more milk per pound of feed while maintaining milk’s natural wholesomeness.

Cows have different needs at different stages. Early lactation cows crave additional energy to support higher production. Late lactation counterparts need less feed to maintain production and pregnancies. Regardless of the feedstuffs for lactating and dry cows, Rumensin helps cows get more energy from every pound of feed.

Approved for use in calves and heifers

Rumensin helps prevent and control coccidiosis in calves and heifers, and promotes increased heifer weight gain during all stages of post-weaning development. It meets the US Food and Drug Administration’s stringent standards for efficacy and safety. On average, provides a 7:1 return on investment in calves and heifers.2

Lactating Dairy Cows

Rumensin means greater milk production efficiency2*—up to 4% more energy per pound of feed, for a return on investment of at least 5:1.3 Rumensin’s ability to help cows get more energy from every pound of feed provides flexibility when formulating rations. Dairy producers can customize the herd’s ration and get more milk from the same feed or the same milk from less feed. By increasing milk production efficiency, Rumensin helps provide value throughout the lactation cycle:

  • During transition and early lactation
    ◦ More energy from every pound of feed
    ◦ No change in dry matter intake (DMI) while cows are in negative energy balance
  • Mid-lactation and late lactation
    ◦ More milk per pound of feed
    ◦ Once energy balance is achieved, DMI may decrease
  • During the dry period
    ◦ More efficient use of feed to maintain body condition

Safely and effectively produce more milk per pound of feed

Because feedstuffs and management goals are unique to each dairy, it’s important to work with your nutritionist to optimize Rumensin to get the most out of your feed. Nutrition experts can help translate the sound science behind Rumensin into real-world results for you.

Common benefits of Rumensin include:

  • 5:1 average return on your investment3
  • More milk per pound of feed (for just pennies per head per day)4
  • Increased milk production efficiency throughout lactation and the dry period
  • Meets the US FDA’s stringent standards for effectiveness and animal, environmental, and human-food safety

Calves and Heifers

Rumensin is approved for increased rate of weight gain and for the prevention and control of coccidiosis due to the protozoan parasites Eimeria bovis and Eimeria zuernii in dairy replacement heifers. Rumensin contributes to the growth and health of heifers through two mechanisms:

  • Improving rumen fermentation5
  • Killing coccidia in the small and large intestines5

In the rumen, Rumensin alters the microbial population, resulting in greater production of propionic acid. Production of propionic acid allows the calf to capture more energy from the ration and serves as the major substrate for glucose synthesis in the liver,6 increasing rate of weight gain in growing cattle and improving milk production efficiency in lactating and dry cows.

Rumensin prevents and controls coccidiosis. Some other products used to control coccidiosis simply interrupt the coccidiosis growth cycle. They prevent further growth as long as the drug is present in adequate levels. When these products are removed from the feed, growth of the coccidiosis parasites resumes and can lead to coccidiosis breaks. Those compounds are referred to as “static” products, in contrast to Rumensin which renders a “cidal” or killing effect. The best way to get solid control of coccidia is to feed Rumensin right from the start. When calves are first born, their starter feed should contain Rumensin at a level ranging from 30 to 60 g/ton. Research has shown that feed intake is maintained at these concentrations of Rumensin in the starter feed.7 By including Rumensin in the starter feed, the coccidia have the opportunity to be killed in a timely manner following ingestion. Good control from the beginning increases the ability of calves to maintain a desired growth rate and avoid breaks associated with changing environment and diets at transition.

Microtracers®

Dairy Image for Microtracers

Feed companies that supply quality feed products to the cattle industry have utilized Elanco's Rumensin as an integral component of their feeding programs. To assist feed manufacturers in providing a quality feed product to their customers, Elanco has added Microtracers® to Rumensin. Microtracers can provide a quick method for confirmation of inclusion or absence of Rumensin in the feed.

Microtracers are extremely small, stainless steel particles with a unique color coating, which do not impact the feed, animal, or environment when Rumensin is used. With the addition of Microtracers in Rumensin, samples of premix or supplements can be tested for the presence of Rumensin in less than 3 minutes.

Elanco provides two Rumensin Microtracers detection kits: the mason jar and the rotary detector.

Rumensin is approved for use in dairy cows in more than 20 countries around the world. Extensive research associated with these approvals shows that the natural wholesomeness and quality of milk from Rumensin-fed cows are maintained throughout lactation. In addition, the FDA has determined that both milk and meat from cows fed Rumensin are safe for human consumption. That’s why no withdrawal is required when feeding Rumensin to dairy cows, heifers or calves.

Important Safety Information

The label contains complete use information, including cautions and warnings. Always read, understand and follow the label and use directions.

CAUTION: Consumption by unapproved species or feeding undiluted may be toxic or fatal. Do not feed to veal calves.

Dosage/Use Levels

Feeding Directions

For Dairy Cows: For increased milk production efficiency
Total Mixed Rations ("complete feed"): Feed continuously to dry and lactating dairy cows a total mixed ration (“complete feed”) containing 11 to 22 g/ton monensin on a 100% dry matter basis.

Component Feeding Systems (including top dress): Feed continuously to dry and lactating cows a Type C Medicated Feed containing 11 to 400 g/ton monensin. The Type C Medicated Feed must be fed in a minimum of 1 pound of feed per cow per day to provide 185 to 660 mg/head/day monensin to lactating cows or 115 to 410 mg/head/day monensin to dry cows. This provides cows with similar amounts of monensin they would receive by consuming total mixed rations containing 11 to 22 g/ton monensin on a 100% dry matter basis.

For dairy and beef replacement heifers
For increased rate of weight gain: Feed at the rate of not less than 50 nor more than 200 mg head per day in not less than one pound of Type C Medicated Feed; or after the 5th day, feed at a rate of 400 mg per head per day every other day in not less than 2 pounds of Type C Medicated Feed. The monensin concentration in the Type C Medicated Feed must be between 15 and 400 g/ton. During the first 5 days, cattle should receive no more than 100 mg per day contained in not less than 1 lb of feed. Do not self feed.

For the prevention and control of coccidiosis due to Eimeria bovis and Eimeria zuernii: Feed at a rate to provide 0.14 to 0.42 mg per pound body weight per day, depending upon severity of challenge, up to a maximum of 200 mg per head per day. The monensin concentration in the Type C medicated Feed must be between 15 and 400 grams per ton. During the first 5 days, cattle should receive no more than 100 mg per day contained in not less than 1 pound of feed. Do not self-feed.

For calves (excluding veal calves)
For the prevention and control of coccidiosis due to Eimeria bovis and Eimeria zuernii: Feed at a rate of 0.14 to 1.00 mg per pound of body weight per day, depending upon severity of challenge, up to a maximum of 200 mg of monensin per head per day. The monensin concentration in Type C Medicated Feed must be between 10 and 200 g/ton.

*Energy is a direct result of the Rumensin mode of action.
†Production of marketable solids-corrected milk per unit of feed intake. Learn more here.
1Elanco Animal Health, Data on File, INAD 1420, Efficacy Report. 2. NADA 095-735, Elanco Animal Health.
2Elanco Animal Health, Data on File, INAD 1420, Efficacy Report.
3 NADA 095-735, Elanco Animal Health.
4 Elanco Animal Health, Data on File, Rumensin Improves Milk Production Efficiency.
5 McGuffey R., Richardson, L. and Wilkinson, J. 2001. “Ionophores for Dairy Cattle: Current Status and Future Outlook.” J. Dairy Sci. 84(E. Suppl.): E194–E203.
6 Greenfield, R., Cecava, M. and Donkin, S. 2000. “Changes in mRNA Expression of Gluconeogenic Enzymes in Liver of Dairy Cattle during the Transition of Lactation.” J. Dairy Sci. 83: 1228–1236.
7 Trial No. T1F190302. Elanco Animal Health. Data on File

Rumensin is a trademark of Eli Lilly and Company or its affiliates.