WormFax NSW – Feb 2012 is now online
Results, map and notes:
As discussed before, unseasonably wet conditions over the last several months in much of NSW means many paddocks are very wormy. Flow on effects from this will extend into Spring and beyond.
With the onset of colder weather, some of the more cold sensitive internal parasites (eg eggs of Haemonchus, Fasciola) will not be able to complete their life cycle (in winter months in colder areas), BUT they have produced plenty of infective stages (eg third stage (L3) larvae in the case of roundworms) on pasture up until now and many of these will make it through to spring, frosts notwithstanding.
What can you do?
* Keep up regular WEC monitoring (WormTest). Don’t guess, WormTest.
* Prepare low worm-risk paddocks for spring lambing. (You can’t rely on long-acting drenches for ever).
* When/if you drench, check that the drench worked i.e DrenchCheck ( WEC 10 days (sheep) or 14 days (cattle) after a drench, preferably matched with a WEC on or just before the day of drenching).
Get advice on when to DrenchCheck in the case of mid-length (eg Cydectin oral) and long-acting (eg Cydectin LA inj; capsules).
* On ‘flukey’ (Fasciola hepatica) farms, give the strategic April/May fluke drench , using a triclabendazole-based drench ( Nitromec(R) is another option in cattle). The April/May fluke drench is the most important fluke drench of the year. It’s important to use a ‘high efficiency’ flukicide at this time. Rotate to a flukicide from a different group if you can if drenching again in Spring.
* Move weaners (cattle, sheep) into low worm-risk paddocks with good tucker.
A case from Carinda (Slattery)
Shaun Slattery (Senior District Vet, North West LHPA) told me of this case:
Haemonchosis in lambs from a property near Carinda (Macquarie Marshes area). A lot of rain in January. Moderate signs of haemonchosis. 15 dead out of a few thousand. No signs of diarrhoea and sheep in fat condition.
Sample collected by Ranger from rectum of dead lamb, but ~ 15 hours post mortem. (Delay in collecting may have increased egg count (epg)????).
Notwithstanding the above, the lab reported a WEC of ~ 67,000 epg.
Investigators were surprised by the count given the relatively low mortality rate. (Yes fellow epidemiologists, I know this strictly is a proportion not a rate! At least I don’t confuse ‘incidence’ with ‘prevalence’ 🙂 SL)
Larval differentiation: Haemonchus: 63%, Trichostrongylus: 27%, Ostertagia (Teladorsagia): 10%. Such large scour worm counts were considered surprising given the absence of scouring (diarrhoea).
Another case of high WECs: https://wormmailinthecloud.wordpress.com/2010/03/17/redux-sky-high-counts-at-bre/
This one was mostly Trichostrongylus (~60,000 epg), which I think is amazing. As to Haemonchus, the highest I have come across is ~ 80,000 epg. Haemonchus of course is somewhat more fecund than scour worms, and Haemonchus – in pure infections anyway – tends to constipate (small,dry pellets) which I guess increases the egg count still further.