Once again, my friend from England has brought a smile to my face with her depiction of what we do on a cattle operation. This time we investigate the pour-on dewormer used on cattle. Cattle dewormer comes in many forms (pour-on, injectable, paste, and crumbles) and there are different chemicals used as dewormer (ivermectin, moxidectin, fenbendazole, and doramectin). To make things even more complicated there are different brand names for the same chemical. For example, Ivermec, Bimectin, and Noromectin, are all brand names for the same chemical ivermectin. Every dewormer targets different parasites and each has different use restrictions for animal type and withdrawal dates. Here is a good comparison chart to make things a little clearer.

Today we will keep it simple and just take a look at doramectin, also known as Dectomax. I hope you enjoy this educational write up on Dectomax with a little humor thrown in from someone who has such enthusiasm for learning all she can about the cattle business. Let me know what you think about deworming cattle.

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Image from Phizer Animal Health product information page.
Today we pregnancy checked our cattle and administered a dose of Dectomax to the bred animals. I have been asked to research why we pour our herd with Dectomax and what exactly it is. Seeing as the mere thought of homework incites me with as much joy as taking out the trash and will even encourage me to wash the dishes (no mean feat, I assure you), I realised that to accomplish this task I would have to make it less of a task (in French the words for homework and task are one and the same) and more of an interesting, pleasurable (and quite possibly vodka-induced) experience. One worth writing and, more importantly, one worth reading.
Had you mentioned to me a little less than a year ago the words “Dectomax” or “doramectin”, I would have looked at you with a face that said, “Errr…sounds nasty” or “I had one of them but the wheels fell off”. How times change. Now I not only know what they both are but I can write a short story about them both. Here goes.
Dectomax is actually a brand name, like “Sellotape” or “Tampax”, for the pharmaceutical company Pfizer, with the active ingredient being doramectin. In its most common form it is a  pour-on solution, contained in a cumbersome white container, usually seen hanging upside-down from a cattle chute with a catheter-like plastic tube hanging from it, filled with the blue liquid Dectomax, draining out, emptying, the very box it comes from. On the end of this tube is a gun. Not a gun as you or I would usually know it but some plastic contraption filling automatically, with a dial to select the correct dosage to be shot over each animal (1ml per 22lb of body weight or a round 60ml as we would like to call it).
Actually I must correct myself. I wrote the above on how Dectomax is most commonly seen. This is not entirely true. This is how Dectomax is most commonly seen in use. Most commonly see it is stored behind green metal cow stalls in a vet room, its snake-like neck lying listlessly, draped over bright blue boxes, labelled “Dectomax” (lest we forget), its nose hanging lifeless in the dust. I’m sure the mice appreciate the scenery.
So why should something that is brought out only a few times a year be so important? Well, it’s an antiparasitic, i.e. it kills all kinds of parasites in cattle, including roundworms, lung worms, sucking and biting lice and mange mites. And let’s face it, none of us want that in our soon-to-be food. Even if it doesn’t, (which I really hope it doesn’t, seeing as I literally do spray my co-workers more often than I spray the cattle themselves), it affects the health and productivity of cattle and, as someone working on a ranch raising beef cattle this is just bad business sense. Bad cattle, bad calves, bad meat, bad business.
Although dosage should be changed for yearling heifers and cows as the weights differ, in practicality a good hand is trying to get in and out of the process as quickly and efficiently as possible so when dosing a variety of weights in one go, a rough estimate by the operator will suffice. Always guestimate on the upside, which also means that if by chance the dose giver “accidentally” de-louses her co-workers opposite, for a smaller cow this has no impact. It can even prove beneficial to the co-workers (although may burn the skin temporarily. But not as much as bleach and will cause no long term damage to the skin.)
Although I work for a beef production ranch, I am aware that other types of cattle exist too; so can Dectomax be used on them too?, I ask myself under the duress of having to write something and having already done the research. Well, yes. It can be used on pregnant beef cows (okay, that’s cheating, they’re still beef cows) and dairy calves 18 months or younger. But the philosophical part of my brain can’t help but wonder – if no withdrawal period for milk has been established, which the New Animal Drug Application 141-095 assures me it has not, why can’t we use this formula on older dairy cows? Or is it because no withdrawal period has been established that we can’t use it? A question not of what have I done now but what haven’t I done now, so to speak? (Dr. Dan?) Now withdrawal periods are important with this drug. Which I guess implies that I really shouldn’t be Dectomaxing (yes, the noun has now become a verb – do Pfizer know about this?) my colleagues. The withdrawal period after treatment is 45 days, so please don’t send your cattle to the sale barn within this timeframe (hence the reason we don’t dose up our open cows – imminent death here they come). Nor the cow that our vet declared pregnant and I Dectomaxed, only to have the vet revoke his decision. And here was I thinking that pregnancy was a definite term – either you are or you aren’t. (Again, Dr. Dan?) Oh, and veal, or pre-ruminating, calves can’t have Dectomax either. Read the instructions, know the weight (approximately) of your Dectomaxable cattle and adjust the dial accordingly. To help, I can tell you that a commercial black Angus cow will weigh somewhere around 1300lb, which means 60ml Dectomax. But get a gun that works – on one that doesn’t properly 60ml will seem like you’re pushing the Atlantic through a drinking straw).
So actually this assignment has taught me something. I already knew what Dectomax looks like, how it is packaged, how it is administered (although it is also available as an injectable source) that it is by far my favourite drug to give, that it is an antiparasitic and that it has a 45 day withdrawal period but I never knew the correct dosage (I mean, without looking at the measure), I never knew that its active ingredient is doramectin, which particular parasites it protected against, that there is a difference in usage between feed and dairy cattle, that you probably really shouldn’t overdose your co-workers, or how much I could enjoy a homework assignment.