How to Give Cattle Hormones

Modern practices of raising cattle often involve using hormones to assist with beef and milk production in encouraging greater feed efficiency (less feed needed for more growth or milk), greater milk production (dairy), and higher growth rates (beef). There are three methods in how hormones are given to cattle. Beef cattle are given growth implants, feedlot heifers and cows are fed, and dairy cows are injected. Breeding heifers and cows are also injected with hormones as a means to synchronize their estrous cycles for artificial insemination, however this is covered in a separate article due to extensive information and various methods associated with synching estrus.

Beef cattle receive three general types of steroid growth implants: 1) Natural hormones composed of progesterone, estrogen and testosterone that are produced by the animal and are used as either single estrogen implants ( Compudose® ), or as estrogen combination ( Synovex® , and Component® ); 2) Zeranol , a biologically active estrogenic product which stimulates the animal to produce more of its own natural hormones ( Ralgro® ); and 3) Synthetic hormones like synthetic testosterone, and trenbolone acetate (TBA) combined with estrogen ( Revalor® and Synovex Plus® ). All of these implants are not approved for use in dairy cows or veal calves, nor hogs or poultry [1] .

Feedlot cows and heifers are also fed a female sex hormone prostagladin known as melengestrol acetate (MGA) in a feedlot to prevent them from going into heat during their finishing/fattening feeding period.

Dairy cows in the United States have been approved receive hormone injections (being recombinant bovine somatotropin [rbST] Posilac® , once a Monsanto drug, but now a Elanco product) for improved milk production. This drug is not approved for use in dairy cows in other countries like Canada, those of the European Union, Australia and New Zealand due to animal health issues like mastitis and lameness [2] . The hormone is only approved for use on lactating dairy cows, not veal calves nor dry (non-milking) cows.

To learn and understand more on how beef and dairy cattle are given hormones, please follow and read the steps, tips and warnings below.

Please Note: This article is merely a guide and an information resource, not a direct source of information on how to give hormones to your cattle. Please contact your veterinarian if you have any further questions or concerns regarding the use of hormones in your animals, and for further details not covered here.

Method 1
Method 1 of 3:

Implanting Beef Cattle

  1. There are many types of implants to choose from, but there are actually only five or seven main brands that are available for use (see the introduction above). The United States has two additional brands (Encore®, Finaplix-H® [3] and Implus® [4] ) to that mentioned in the introduction that are approved for use in Canadian beef cattle. Australian producers have Progro®, Ralgro®, Synovex®, and Revalor® approved for use in beef cattle [5]
    • Your choice will reflect the effectiveness of it in your herd, because each type of implant product is intended for use in different types of cattle. You need to know the sex (i.e., heifers or steers), age, weight, length of time the implants are effective, and classes of cattle (nursing calves, grass cattle, backgrounding, feedlot, or breeding cattle) of the animals you want to implant.
    • Some implants are more effective than others, but effectiveness is actually limited by what you feed your animals and how you raise them. Implants can only do so much, but they will not make the animal grow better for you, they are only a means of assisting growth and feed efficiency along with a proper feeding program and responsible, humane handling. An implant can be next to considerably ineffective if you do not feed your animals properly or, in other words, you fail to meet their nutritional requirements.
  2. The steer or heifer should be put into a squeeze chute and locked in a head-gate for the procedure. The ear is going to be needed for this, which means the head needs to be easily accessible in order for the implant to be injected.
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  3. This is optional, but useful if this is your first attempt at performing an ear implantation and don't want to have to deal with a struggling animal. You can restrain the head by using a rope halter or a bull lead (nose tongs), or a nose brace that can be attached to the head gate.
    • If you choose to use a rope halter, put it on by first looping the head piece over the ears, then the nose band over the muzzle and the chin piece (the adjustable part of the halter) tightened snug against the chin. Next, loop the end of the lead rope once around one of the bars that sits behind the head gate, and pull tight until the animal's head is snug up against the side of the head-catch. Secure using a quick-release knot.
    • Bovine nose tongs are put on by inserting the ball points of the tong inside each nostril (one ball point per nostril) and locking the tool in place by squeezing the handles together and keeping tension on the rope or chain that is attached to the ends of the handles. A rope should be tied to the chains, then secured in the same manner as with the rope halter above.
  4. Using a cotton swab dipped in germicide or disinfectant, generously swab the site of the ear to where the needle will be injected. The needle of the applicator gun should also be disinfected if not already done so.
  5. This should be done before you have the animal in the chute and head restrained. The implant gun is like a hand-gun except with a sharp, large-gauge needle at the "business" end. The barrel holds a cartridge of several small implant pellets which are injected under the skin of the ear, and slowly release their contents over time.
    • These pellets are contained in a cartridge because they are too small to handle alone like small bullets that can be loaded into a .22 rifle. One cartridge contains 10 to 100 pellets, depending on the product (i.e., Synovex® vs. Revalor® vs. Ralgro®; each have different guns and different methods on loading each for injection).
    • Load the gun according to the label that comes with the implant gun or re-fill cartridges. Do not use a cartridge from one product for a gun of a different product, i.e., don't load a cartridge meant for a Rev-X Universal Applicator Tool (for Revalor® implants) into a Synovex® gun.
  6. You will only need one ear (not both) to give an animal its required dose, preferably one that does not have an ear tag in it, if possible. Divide the ear into three imaginary sections. Locate the middle third of the ear. Implants are going to be placed on the outside of the ear, all under the skin, and in the middle of that ear [6] .
  7. Holding the ear in one hand, use your other hand to guide the need of the applicator tool so that the needle is parallel to the surface of the ear, the sharp end of the needle closest to the surface and at the outer third of the ear (or the third that is closest to the tip, not the base [near the head]). Make sure your finger is off the trigger during this step to prevent premature ejection of the pellets. Using your finger on the inside of the ear to feel for the needle (and ensure it does not poke out the other side), push the needle until it is completely submersed beneath the skin.
  8. This may need to be done multiple times if more than one pellet is to be administered into the ear. You should feel a straight line of pellets running parallel to the ear, this indicating that the procedure has been properly done [7] . Once you have ejected the pellets into the ear, pull out the needle in the same direction you pushed it in.
  9. If there are no more things that need to be done (such as vaccinating, dehorning, castrating or tagging), then release the animal from the chute.
  10. You will need to keep the implant gun disinfected each time and ready to go for each animal, and each animal restrained as necessary.
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Method 2
Method 2 of 3:

Feeding Cows and Heifers

  1. Melengestrol acetate (MGA®) is a product that is added to the feed that is being fed to them, and comes as dry or liquid premix form, and in medicated range pellets [8] .
  2. The label will give instructions on how much MGA needs to be given based on number of head to feed per ton of feed per day. The rule of thumb for supplementing MGA® 200 Premix and MGA® 500 Liquid Premix is that heifers and females get 0.25 to 0.5 mg per head per day, with optimum levels of 0.35 to 0.5 mg/head/day for maximum estrus suppression [9] . MGA® 100 Premix should be fed so that females get 0.4 mg/head/day [10] .
    • The only MGA product approved for use in Canadian cattle is MGA® 100 Premix [11] . The others, including MGA® 100 Premix, are approved for use in American cattle.
    • MGA® 100 Premix contains 100 mg of melengestrol acetate per pound (lb), MGA® 200 Premix 200 mg per pound, and MGA® 500 Liquid Premix 500 mg per pound. How much MGA is mixed in with the feed depends on the type of feed as per compliance with the Food and Drug Agency's (FDA) Medicated Feeds Program.
      • As per the program, there are two types of feeds: Type B and Type C medicated feeds. Type B medicated feeds are feeds that are created for the purpose of manufacturing other Type B medicated feeds, not to be fed to livestock. Type C medicated feeds are those where a medicated feed or Type A medicated article (like MGA® 200 Premix) or a Type B medicated feed has been heavily diluted with a non-medicated feed for the purpose of being fed to livestock.
  3. As per the aforementioned step, you will need to determine whether you are putting MGA in Type C (non-medicated) feed, or Type B feed (to be turned to Type C feed). The label will indicate how much MGA can be mixed with the feed you intend to feed to your heifers. MGA® 200 Premix, for example, needs to be mixed at a rate of 1.25 to 10 pounds per ton of non-medicated feed to create a Type C medicated feed with 0.5 to 2.0 grams of MGA per ton.
    • Remember, one US short ton is around 2000 pounds (~ 907 kilograms), and that MGA@ 200 contains 200 mg of MGA per pound of the premix. Also, try not to get mixed up on the conversion measurements between empirical and metric measurements!!
    • MGA@ 500 Liquid Premix contains more complicated mixing directions that will need to be followed. Basically, though, this premix should be mixed with a non-medicated feed at a rate of 0.5 to 4 pounds per ton so that you get a Type C feed that contains 0.25 to 2.0 grams of MGA per ton.
    • MGA® 100 Premix should be added to feed at a rate of 0.25 kg to 1.0 kg per 1000 kg of feed so that heifers get 0.4 mg of feed per head per day.
  4. The amount you measure out to give to your animals to be mixed in the feed will depending on how many animals you are feeding and how much feed you have to use to mix the MGA in.
    • The feed that is typically mixed in with is grain or bag of feed that is a mix of grains and intended as a supplement or to top-dress on a mix of silage and hay, especially in a feedlot environment. It's not feasible to mix MGA premix directly with silage or hay.
  5. The resulting manufactured feed should be fed as a top-dress on grain, roughage, or mixed with a complete ration so that cattle get the Type C feed at a rate of 0.5 to 2.0 pounds per day [12] .
    • This feed is not intended nor permitted to be fed to steers, breeding cows or heifers, bulls nor veal or suckling calves, and doesn't work on spayed heifers or steers. It is only intended for feeder cows or heifers that are fed in confinement for slaughter to suppress estrus for the intended period of time they are in the feedlot.
  6. You will need to feed this premix as directed daily to prevent heifers from coming into heat. Any lapse of feeding this can result in heifers going into estrus at least a day later.
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Method 3
Method 3 of 3:

Injecting Dairy Cows

  1. You will only find this injectable hormone in the United States, so if you are an American dairy farmer looking for Posilac®, you will find it being sold at your local veterinary clinic or at the local farm supply store. Posilac® is the only hormone drug on the US market that is intended and used for increased milk production in dairy cows. There is no similar drug on the market nor for legal use in dairy cows outside of the U.S.
  2. Like with all other drug labels, the Posilac® label will tell you the optimum dosage, where to inject and how often, and for which animals it is intended for. Use this information to perform the proceeding steps below.
  3. Dosage depends on the weight of the cow, and this is recorded for each individual cow in all dairy operations. Majority of dosages are calculated based on approximate weight, thus there is no need to know the exact weight (that down to the pound) in order to be able to give the correct dosage. As long as it is within the correct hundred weight, the dosage will be precise enough to administer.
  4. Unless you have a dairy operation where cows are confined to stalls for the duration of their lactating period, you will need to move the cow into a squeeze chute in order to give the hormone. Restrain the head in a head-catch or head-gate so there's less chance that she will try to move up and down the chute on you while you are giving the needle.
  5. As directed in the wikiHow article How to Give Cattle Injections, the syringe will need to be filled up with the required dosage by putting air into the bottle via syringe then slowly pulling back the plunger to allow the liquid to flow into the syringe until you get the required dosage. Once done, tap the syringe and depress the plunger slightly to let any air bubbles out.
  6. Unlike with beef cattle, you can inject Posilac into the rump of the cow, as well as the neck. The rump injection would not be in the muscle, but rather in the skin that stretches between the tail head (at the very base of the tail) and the hip bones that are known as the "pins" of the pelvis. This is found right at the top of the rump of the cow and make up the tail-head depression. Avoid the folds that extend from under the tail, known as the caudal fold. This is the area where USDA (United States Department of Agriculture) tuberculosis testing is done. Since Posilac® must be administered subcutaneously (under the skin), the tenting technique on the neck is also recommended. The area behind the shoulder is also a recommended area to inject, though tenting in this area is a little more difficult. After inserting the needle, lowly depress the plunger of the syringe until all the fluid is gone out of the syringe.
  7. Once the injection process is complete and no other medications or supplements need to be administered, the cow can be released back into the herd.
  8. The Posilac® label recommends that cows be injected every 14 days, starting 57 to 70 days post-calving and continued until the end of lactation. It's best to keep records to keep track when which cow was injected, especially when you have a large dairy herd that is not in the same stage of reproduction or lactation as a means to achieve year-round milking.
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      Tips

      • For giving beef cattle implants
        • Different steroid implants are intended for different types of cattle. Implants meant for steers contain estradiol, and implants for heifers contain testosterone or TBA. The label will state which implant is for which type of animal.
        • There is no withdrawal period for implants. Because the implants give very little hormone over a long period of time, food safety testing that has been done has deemed the hormonal implants to have no adverse effects on food quality and safety.
        • Always make sure to implant behind the ear, not in the ear. The skin is looser behind the ear (just like with human ears) which makes it easier to insert the implants, and to avoid injecting the tiny capsules into the cartilage.
        • Often when processing cattle with several people, one person may be responsible for implants only while the others are responsible for tagging, vaccinations, dehorning, etc.. This way the processing goes much quicker.
        • Practice makes perfect. Don't expect to get it on the first try, you will be able to implant cattle with lots of practice and lots of experience having to deal with feisty and ornery cattle not used to being handled so much.
        • Always read the label. Not all drug companies offer the same dosage, and the dosage is not the same for all cattle, so be sure you know how many capsules you are giving to each steer, heifer or calf.
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      • Feeding Heifers MGA
        • Applicable to feedlots only, limited used for breeding heifers. Adult cows can be given this too only if they are also being finished in the feedlot for beef. Do not feed to steers or calves.
        • Be sure you are familiar with the types of medicated feed that can be and cannot be fed to cattle. The document by the FDA, for example, is a good resource to go by, but can be daunting to follow. Be sure to read it through before you proceed with any kind of medicated feed.
        • Always read the label, and know your conversions! Quite often the drug companies that make these drugs try to make things easier for a producer to follow without having to force the producers to do any extra arithmetic and converting on their own. However, it doesn't hurt to do a little extra math just to understand how much MGA is really being fed to your animals.
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      • Injecting dairy cows with Posilac®
        • This drug is for lactating dairy cows only, not for any beef cattle, nor for non-lactating cows, heifers nor veal or bottle calves.
        • Make sure you are injecting this drug into a different injection site than what was done last. For instance, if you injected this drug into the neck, you should consider injecting on the other side of the neck, behind the ribs, or at the tail-head depression. There are two sides to a cow, so you have six optional areas to inject Posilac® into.
        • It is not a requirement for all dairy herds to use this drug. It is only the dairy producer's choice of using this drug for his herd if [s]he wants to increase milk production. However, the milk that is sold from such farms should be labelled as non-rbST milk as per voluntary FDA regulations.
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      Warnings

      • Cattle are unpredictable and dangerous, especially those that are not used to being handled regularly. Make sure you know how to handle them and follow safety procedures when restraining and handling them for one out of the two the methods above.
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      • Please seek veterinary assistance if you have any questions regarding your herd based on the subject matter of this article.
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      References

      1. ↑ FDA Steroid Hormone Implants Used for Growth in Food-Producing Animals ( http://www.fda.gov/AnimalVeterinary/SafetyHealth/ProductSafetyInformation/ucm055436.htm )
      2. ↑ A meta-analysis review of the effects of recombinant bovine somatotropin ( http://www.ncbi.nlm.nih.gov/pmc/articles/PMC280709/ )
      3. ↑ Implanting Beef Cattle, UGA Extension ( http://extension.uga.edu/publications/detail.cfm?number=B1302 )
      4. ↑ Beef Cattle Implants, CattleSite.com ( http://www.thecattlesite.com/articles/744/beef-cattle-implants )
      5. ↑ Hormonal Growth Promotants for Use in Beef Cattle, Government of Western Australia Department of Agriculture
      6. ↑ Synovex S for Animal Use Steps to Implant ( http://www.drugs.com/vet/synovex-s.html )
      7. ↑ Synovex S for Animal Use Steps to Implant ( http://www.drugs.com/vet/synovex-s.html )
      8. ↑ 0.5 MGA Pellets ( http://www.ranch-way.com/products/feedlot-supplements/ranch-way-0.5-mga-carrier-pellets-medicated-with-melengestrol-acetate )
      9. ↑ MGA® 200 Premix for Animal Use ( http://www.drugs.com/vet/mga-200-premix.html )
      1. ↑ MGA® 100 Premix ( http://www.drugs.com/vet/mga-100-premix-can.html )
      2. ↑ CFIA Medication Sequencing Guideline for Management of Drug Carryover ( http://www.inspection.gc.ca/animals/feeds/inspection-program/medication-sequencing/eng/1389362488069/1389362490053 )
      3. ↑ MGA® 200 Premix for Animal Use ( http://www.drugs.com/vet/mga-200-premix.html )

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