In short, it’s hard to predict. The graph below, produced by Gribble’s Veterinary, shows the highest weekly spore count from mid-January (week 1) in the Central Waikato for the past four seasons. It’s important to recognise that while some seasons are clearly worse than others (2016!), almost every season shows a similar pattern – spore counts climb rapidly in early February (week 3) and remain elevated until the end of May (week 20). Last season was gentler than previous years, but that has little bearing on what this season could bring.
Therefore, it’s critical to have a zinc supplementation plan in place during the risk period.

What are my options for zinc supplementation?

Zinc can be supplemented in four main ways: bolus, in-feed, water treatment or drenching. Each method has its pros and cons, which you should discuss with your vet. The most important thing is to spend time ensuring you have calculated the correct amount of zinc. Bad maths is the biggest reason for animals either being underdosed or overdosed with zinc during the facial eczema period. Both can lead to significant problems for your animals.

The best way to confirm whether your animals are protected is for your vet to take blood samples from 10 random animals per mob, two weeks after the start of supplementation. Dose rates can then be tweaked accordingly.

What should I do next?

Spore counting on our monitor farms has begun. The best way you can keep informed about the facial eczema risk in your area is to sign up to our weekly email updates. Visit www.anexa.co.nz/newsletters and select ‘spore counts’ from the drop-down list.

Graph source: Gribble’s Veterinary NZ, 2019. Reproduced with permission.