Our hoggets are now around seven months old and building their immunity to parasites. The faster they do this, the quicker they’ll handle parasites and not require drenching. We need this to happen as quickly as possible.     

Immunity develops when an animal is well fed and has all their important trace elements at adequate levels (Selenium, Vitamin B12, etc.). A high-protein diet will aid immunity development.   

The trigger for any immunity is the presence of the pathogen (parasite, bacteria, virus etc.). It’s important to know that they only need a little bit of exposure to form immunity.   

Farmers often say they’re “challenging their hoggets to develop their immunity”. Extreme challenges, such as long gaps between drenches or not drenching when it’s needed, won’t strengthen immunity. Instead, the animal’s energy goes into simply surviving the challenge, not building resilience.  

It’s understandable that some farmers put hoggets under high larval challenge to see how they cope. This approach is fine – so long as you recognise it can hinder immunity development and stunt growth.    

One of the biggest challenges in New Zealand’s pasture-based farming system is keeping the parasite challenge low enough to prevent production losses. 

We’re encouraging farmers to look at crops and new grass paddocks for fattening their lambs. But we wouldn’t want to avoid all parasite challenges for replacement hoggets, as they will need a little exposure to develop immunity. So, graze them on permanent pasture (with low larval challenge where possible).  

We’re always happy to chat, so please get in touch if you’d like to know more.