Skip to Content

Rumensin CRC (Canada)

This page contains information on Rumensin CRC for veterinary use.
The information provided typically includes the following:
  • Rumensin CRC Indications
  • Warnings and cautions for Rumensin CRC
  • Direction and dosage information for Rumensin CRC

Rumensin CRC

This treatment applies to the following species:
Manufacturer: Elanco

monensin Controlled Release Capsule


DIN 02082128

For oral use in cattle only.


The Rumensin CRC is a controlled release formulation of monensin (as crystalline monensin sodium) contained in a plastic capsule equipped with retaining wings. Slowly releasing monensin from the opening at its end, the capsule will remain effective for an average of 95 days after administration in lactating dairy cattle, and an average of 80 days after administration in growing cattle on pasture (See Safety Study Information and Cautions).

Active Ingredient

monensin (as crystalline monensin sodium)

32 g per capsule

Rumensin CRC Indications

1. As an aid in the prevention of subclinical ketosis in lactating dairy cattle.1

2. For the reduction in fecal shedding of Mycobacterium avium paratuberculosis (MAP) in mature cattle in high risk Johne’s disease herds as an aid in the herd control of Johne’s disease as one component of a multi-component Johne’s disease control program.2

3. As an aid in reducing the incidence of bloat and bloat associated mortality in growing cattle, weighing from 300 kg (660 lb) to 400 kg (880 lb), on pasture containing legumes.

4. As an aid in the prevention of coccidiosis caused by Eimeria zuernii and Eimeria bovis in cattle weighing from 300 kg (660 lb) to 400 kg (880 lb).


1Reductions in the incidence of clinical ketosis and displaced abomasum may occur in conjunction with the reduced incidence of subclinical ketosis.

2Other considerations for effective Johne’s disease control program include: identification and culling of clinical cases and heavy shedders, and reducing the exposure of calves to the pathogen (e.g., feeding colostrum/milk to calves from animals that are disease free, using uncontaminated pasture to raise calves and replacement heifers, etc.).

Dosage and Administration


For indications 1 and 2, administer one capsule orally 2 to 4 weeks prior to expected calving date, using the Rumensin CRC administration tool.

For indications 3 and 4, administer one capsule orally to growing cattle weighing from 300 kg (660 lb) to 400 kg (880 lb), at the time of treatment, using the Rumensin CRC administration tool.

NOTE: An animal safety study showed no adverse effects in dairy cows when Rumensin CRC was used in herds feeding Rumensin Premix up to a dose of 16 ppm monensin activity.


Care should be exercised when administering the Rumensin CRC to ensure the delivery to the correct location in the pharynx. Be sure that the head of the administration tool is past the base of the tongue. The correct administration tool position will be indicated by the animal beginning to swallow. Failure to do so may result in soft tissue damage or regurgitation.


Adequate animal restraint is required to properly administer this capsule. A headgate or chute used to restrain the animal must limit forward/backward motion and allow the animal’s head to be held in the forward extended position and without pressure on the neck (to prevent choking).

Each capsule has an individual embossed number along the capsule body. This should be recorded with the corresponding animal identification number so that, should a capsule be regurgitated, the animal can be identified.

1. Identify each animal as it is dosed and match the animal identification number with the number embossed on the side of the capsule to be used.

2. Fold wings down along capsule body and place the capsule in the head of the Rumensin capsule administration tool, orifice end first.

3. Standing to one side of the animal, restrain it with its head and neck stretched forward and held firmly against your side. Grasp the animal with one hand in the corner of the animal’s mouth. Introduce the head of the administration tool containing the capsule into the animal’s mouth, avoiding the front teeth.


4. Once the administration tool is inside the animal’s mouth, straighten it so as to avoid the molar teeth.

5. Insert the administration tool past the base of the tongue making sure to avoid the molar teeth. As the animal swallows, the tongue will come forward and the administration tool will move easily over the base of the tongue. Do not use excessive force. Should resistance be encountered, withdraw the administration tool slightly and repeat the procedure.

6. Be sure that the head of the administration tool is past the base of the tongue. The correct administration tool position will be indicated by the animal commencing to swallow. When this occurs, eject the capsule from the administration tool by pressing the plunger.

7. Remove the administration tool from the animal’s mouth.

8. Hold treated cattle in a confined area for at least one hour after administration of the capsule to observe for failure to swallow or for regurgitation. If a regurgitated device is found, identify the animal by matching the animal identification number with the number embossed on the capsule and redose the animal with an undamaged capsule.

9. Recheck all cattle for up to 4 days after dosing for capsule lodging in esophagus (See Cautions).


Do not use in cattle weighing less than 300 kg (660 lb) body weight.


In growing cattle, do not feed diets containing ionophores for at least 80 days after administration of this capsule. Reduced average daily gain may result.

Growing cattle on pasture are no longer protected from bloat approximately 80 days after administration of Rumensin CRC and retreatment may be required in some animals, considering pasture conditions. (See Safety Study Information).

Recheck all cattle for up to 4 days after dosing for capsule lodging in the esophagus. Immediate signs of lodging within the first hours of administration include bloat which may be followed by coughing, drooling, inappetance and unthriftiness. If lodging is suspected, contact a veterinarian immediately.

Do not allow canines, horses, other equines or guinea fowl access to formulations containing monensin. Consumption of capsule contents can be fatal.

Treatment with Rumensin CRC has no impact on the cure of Johne’s disease, and may have no impact on decreasing the risk of culling in animals diagnosed with Johne’s disease. Treatment with Rumensin CRC is not an alternative to identifying and culling of clinical cases/heavy shedders for effective control of Johne’s disease.


Do not administer Rumensin CRC to dairy cows in herds feeding Rumensin Premix exceeding a dose of 16 ppm monensin activity. In growing cattle, do not supplement monensin from other sources. No preslaughter withdrawal period or milk withholding time is required when this drug product is used according to the label directions. KEEP OUT OF REACH OF CHILDREN.

Adverse Reactions

The most common reported* adverse events in descending order of frequency are: lack of efficacy, adverse events associated with administration or capsule regurgitation, monensin toxicity, and accidental monensin exposure. Lack of efficacy reports are rare and primarily originate from countries other than Canada where Rumensin CRC is used as an aid to control bloat in pasture cattle. Adverse events associated with administration are very rare and often involve trauma to the oropharynx or lodgement of the capsule in the esophagus or trachea. Such events may be due to incorrect administration technique. Monensin toxicity is very rare and may occur due to breakage of the capsule with exposure of the monensin dose to the rumen. Breakage may occur if the animal chews the capsule during incorrect administration. Adverse events involving accidental monensin exposure are very rare and primarily involve canines chewing on capsules. (*Includes worldwide adverse event reports received by Elanco Animal Health from 01/08/2007 to 31/07/2009).


An in vivo release rate study was conducted using 15 beef steers grazing on alfalfa/grass pasture. After 56 days on pasture, animals were euthanized and the capsules retrieved. No adverse events occurred during this study. Data from this study indicate that the payout rate is variable between animals. The average release rate was 400.7 +/- 43.1 mg (1 SD) of monensin per day. Based on the release rate it is expected that in pastured cattle, Rumensin CRC will payout over an average of 80 days +/- 8.3 days (1 SD). The implications of this variability in release rate, in pastured cattle, is that the duration of protection against bloat and coccidia will be variable among these animals.


Store in original container in a dry place below 30°C.

REVISION DATE: January 2018

Rumensin, Elanco and the diagonal bar logo are trademarks of Eli Lilly and Company or its affiliates.

Elanco Canada Limited, 150 Research Lane, Suite 120, Guelph, Ontario N1G 4T2







CPN: 1231132.0

(successor to Novartis Animal Health Canada Inc.)

Telephone:   519-821-0277
Customer Service:   800-387-6325
Fax:   519-821-7831
Every effort has been made to ensure the accuracy of the Rumensin CRC information published above. However, it remains the responsibility of the readers to familiarize themselves with the product information contained on the Canadian product label or package insert.

Copyright © 2018 Animalytix LLC. Updated: 2018-11-30