Here is an article Bruce Watt has written for his regular column in the Bathurst (central tablelands, NSW) newspaper. Used with permission here)
Its good stuff as usual and topical because of the very wormy pastures in his part of the world and to the south (Yass, Goulburn etc areas – see comments above re WormBoss News)
As always note the context (it is written for the Bathurst area), but there are some good general messages here for those further afield.
You will note that we have Bruce’s dinkus here with this article (reproduced below). It is only today that I found out what a dinkus is, apart from the rude definitions in Urban Dictionary. Dinkus apparently is a typography/editorial term referring to the picture and title etc of a person heading the article they wrote. (It can also refer to ‘separators’ used within chapters in books). You will be pleased to note that I have a dinkus as well (phew!), from my occasional articles in The Land newspaper.
I didn’t have a dinkus when I was young boy, but I did have a dinky.
I am not sure the Bathurst newspaper would like BW’s articles being reproduced here: I suspect many people only buy that paper to see what Bruce has written.
To find out about "LHPAs", check out www.lhpa.org.au. For overseas readers,"lamb marking" is when lambs get their tails docked, boys get bits removed, and vaccination is usually done.
I am occasionally asked if lambs should be drenched at marking. I usually answer that there is no benefit in this practice. After all lambs, 2-8 weeks of age are generally on a high protein (milk) diet with limited grazing. So they consume few worms and because of the high protein diet, handle them.
This all changes at weaning when lambs are suddenly full time grazers on lower quality feed but with virtually no resistance to worms. This is why drenching lambs at weaning is essential.
However, this year I have seen lambs affected by worms prior to weaning. In some cases, this has been barber’s pole worm and in some cases, the winter scour worms. This is most unusual (although I also saw BPW in lambs before weaning last spring).
My TLHPA district vet colleagues and I think this is occurring because conditions have been so conductive for worms over the last year that at least on some paddocks we have a massive build-up of worm larvae.
These worm larvae are affecting ewes post lambing, especially those ewes already doing it a bit tough. This high level of pasture contamination is also affecting lambs especially the older lambs in the mob and those learning to graze early.
How can you tell if you have massive worm larvae levels on your lambing paddocks? Firstly, if it is winter scour worms, some ewes will lose weight and others will have evidence of green diarrhoea on the hocks and breach.
If is barber’s pole worm, as you know, ewes and lambs fall to the back of the mob, collapse weak and pale and die. I have seen both in the past two weeks, both in ewes and lambs.
If you suspect a worm build-up on your lambing paddocks, you can best confirm this by testing manure samples for a worm egg count. You should be able to pick lamb manure from that of ewes and so can determine worm levels in both.
If the worm egg count (WEC) is only 200-300 the mob should be right until weaning when the lambs must be drenched and the ewes drenched with their first summer drench.
However, if the WEC is high, and especially if some show signs of worms, you need to act now. You can either drench the ewes and lambs (at marking or later) onto a different paddock with fewer worms. That is easier said than done.
You could also drench ewes and the older lambs with a short acting drench, which may relive the situation. Alternatively, you can also use long acting products such as moxidectin or capsules.
I have mentioned before that long acting products have the disadvantage of promoting worm resistance more than short acting drenches and so should be used sparingly. Now may be the time to use them. If using long acting products consider a drench to eliminate those worms that have survived as the drench reaches the end of its life.
You must ensure that the drench you choose is effective. We have seen some cases recently where abamectin and moxidectin are moderately to completely ineffective against BPW. A WEC both before you drench and 10-14 days after drenching will tell you if your drench worked. In a season like this, you can’t afford to guess.
Finally, it is also time to think about the paddock you plan to use for weaning lambs. A heavily contaminated pasture will be disastrous for weaners. An ideal paddock would be one in which cattle are grazing now. An alternative is a paddock in which dry sheep with a very low worm burden are grazing. The worst option is a contaminated lambing paddock.
Senior District Veterinarian
Bruce Watt BVSc, MS, MACVSc
Tablelands Livestock Health and Pest Authority
31st August 2011
(The picture doesn’t do Bruce justice).Sex and parasites Further to the item on ‘sex and parasites’ in an earlier WormMail, liver fluke guru Dr Joe Boray tells me that the intermediate host snail, Lymnaea tomentosa, does very well by self fertilisation. However they also copulate from time to time, just for fun. (This sounds like an anthropomorphism to me). Who said parasitology was boring? By the way, did you know that the sheep blowfly (L. cuprina) smells through it’s feet? (ie its feet smell). I was reminded of this when working with Ed Joshua and Alan Casey (NSW DPI operatives) at some farmer meetings in the central west a few weeks ago. Ed mentioned the smelling feet in his talk on fly biology. I am not sure about Ed’s feet. Regards SL