Record rain delivers parasite problems for farmers

08 August 2022 

Following the NIWA announcement of New Zealand’s wettest July the country’s leading laboratory analysing faecal egg counts (FEC) says the rain has led to record parasite numbers in sheep across Aotearoa. 

NIWA’s statement said "record-breaking rain, temperatures and wind were all part of the weather story for July 2022 in Aotearoa New Zealand", with rain being "perhaps the most memorable feature of the month". From July 11 to July 31, five separate weather events caused flooding around the country, with many regions impacted. 

Greg Mirams, Managing Director of Techion which owns FECPAKG2 and runs a laboratory processing more than 30,000 FEC samples annually, says July’s weather conditions have led to record parasite burdens in livestock across the country. 

“We have received counts of more than 3000epg (eggs per gram) over the past eight weeks across the South Island when their levels should be less than 300epg. In three alarming instances we’ve analysed results from Southland hoggets that were tested at almost 3500epg and recorded counts above 3000 EPG on farms in Canterbury and Marlborough.” 

“Further north, in Hawkes Bay we had parasite burdens in hoggets with counts of 2100epg, while mobs in the Gisborne and Manawatu-Wanganui areas had counts of more than 1200epg.” 

In general, sheep with FEC counts of more than 500epg will be under stress from parasites and will likely be suffering a drop in condition.  

Greg Mirams says while wet and challenging conditions over the past couple of months have had the biggest impact on the parasite challenge, other factors like the high levels of pasture contamination through the autumn have also played a part. He also cites feed availability; animals under nutritional pressure are more susceptible to parasites as are stock that have to adjust to different types of winter feed.  

Greg explains; “Many farmers believe drenching on a calendar schedule protects their animals from a parasite challenge. Furthermore many think it’s unnecessary to drench in winter when grass growth is slowed. However, as these recent results prove, the parasite challenge continues through winter, particularly when conditions provide plenty of rain and temperatures which are a little warmer than traditional averages. The impact of climate change is directly reflected in the disease challenge to livestock.” 

“By FEC testing frequently throughout the year, farmers can catch the parasite burden before it impacts stock. Weight loss, slow weight gain and poor condition and all signs that stock are impacted by a high parasite challenge,” Greg says. 

“It is important to remember these signs may even occur when sheep have been regularly drenched and have adequate feed. Drench resistance, high levels of larvae intake or poor drench practice can result in animals having a parasite burden even when they have been drenched regularly. Therefore it is vital to FEC test regularly throughout the year as well as follow up testing after drenching to ensure that the drench is working effectively.”  

FECPAKG2 is a simple easy to use tool that allows farmers to undertake FEC tests on farm at any time. Digital images of the samples are uploaded to the internet for analysis and farmers receive the results within an hour. Results are stored in a secure online portal that allows them to track the parasite burden by animal or by mob or to identify which paddocks have been contaminated. Over time, this information helps farmers understand where problem paddocks are and which mob they need to target with drench.