A gut worm’s garden of eden!

Winter 2021 was the warmest winter on record, surpassing the record that was set just last year. Temperatures were above average (+0.51 °C to +1.20 °C of average) across most of NZ with pockets of well above average temperatures (>1.20 °C above average) recorded in Northland, Waikato, Wairarapa, Nelson, Tasman, West Coast, Canterbury, and Otago. Coupled with normal to high levels of rainfall across most of the country, it’s no surprise that the veterinary team from Boehringer Ingelheim Animal Health reported high levels of parasite challenge through winter - clinical disease and deaths were seen in calves in the middle of winter on both the North and South Island.

R2s at Risk

With favourable weather conditions over both autumn and winter for gut worms, R2s are at particular risk. This is because of a neat little trick that the gut worms have. They can stop their development for a short period of time inside the calf. This form of hibernation is done over the colder months and development starts again in spring. If there were lots of worms about in winter, then the danger is that they will all start to develop together in spring.

Killing Hibernating Gut Worms

It’s important to clear out the hibernating worms before they start to develop. R2s more commonly than not get a pour-on or injectable drench. Combination pour-ons, such as ECLIPSE will kill hibernating worms. Although, just a note on using pour-ons in winter - long winter coats and cold temperatures can increase the time it takes for the drench to go through the hide. The injectable drenches, ECLIPSE E, and oral drenches, MATRIX C, will also kill hibernating worms. It doesn’t matter which way you choose to give your drench. What does matter is that it’s done correctly. Check your guns, check your scales, check your technique and double check the dose.

Weaning Drenches

The majority of young calves get an oral drench. The white drench (benzimidazoles or BZs) can only be given orally so it’s a good idea to use this active when you can. We know that using all 3 actives together in a triple drench reduces the chance of resistance emerging. So, if you are drenching young calves, you should ideally be using a triple. This also means that you can guarantee there’s a white drench component in there, as some dual actives don’t contain a white drench.

Make the move from 2 to 3

Double combination drenches that contain white and clear drench actives (BZ and levamisole, e.g. ARREST C) have been commonly used in this age group. Considering the need to manage parasite resistance in cattle, it’s also appropriate to use a triple combination as an alternative to a double. Our recommendation is to use Iver Matrix Mini-Dose HiMineral. It’s a unique triple combination cattle drench specifically developed for use in young calves under 120 kg due to the inclusion of ivermectin as opposed to abamectin. The ivermectin provides excellent control of the Ostertagia spp. (brown stomach worm) and will support the reduced chance of developing parasite resistance on your property.