How To Lose Money By Drenching

Read on to found out how.

HOW TO LOSE MONEY BY DRENCHING

The experts tell me that animal health inputs are not a large part of the cost of production, but drenches still cost money. Worms cost even more. How much do they cost? Here are a couple of graphs from a 2006 MLA report by David Sackett and others. OK, any figures from economic modelling are rubbery, even when produced by vets, but they can still be a useful guide.

Stephen Love Veterinarian/ State Worm Control Coordinator Industry & Investment NSW With spring upon us, cattle, sheep and goat producers are likely to give their drench guns a work out between now and Christmas. A lot of them will lose money along the way.

9

Worms cost a lot. Look at sheep worms for example: $369M a year, about 90% of which is largely invisible, from production losses.

These numbers vary depending on the region, worm species, and the individual drench being used. How many producers have tested their drenches in the last three years? Probably no more than 10%. OK, we are all human, and have plenty of other things to think about, but the fact remains that many of you are still losing money unnecessarily.

How do you manage worms? Integrated parasite management (IPM) includes nonchemical and chemical control measures. The non-chemical parts include animal genetics, nutrition and grazing management. The chemical part of the package obviously is treating animals with anthelmintics or drenches. Treatments include effective ‘quarantine’ drenches – so that you do not import resistant worms – as well as treatments guided by a worm control plan fine-tuned by regular worm egg count monitoring. That at least is best practice.

What about cattle worms? To date, there are few Australian reports of drench resistant cattle worms in the scientific journals. However, field reports of resistance in Australia have increased steadily in recent years. Meanwhile, across the Tasman, reports published in the New Zealand Vet Journal (December 2006) paint an alarming picture with respect to resistance of cattle worms, and as well as worms of small ruminants of course.

So, talking about money, which drench is the most expensive? The one that doesn’t work! Yes, you have heard this before and have probably guessed where I am going with this.

Here is a summary of the 2006 report by Waghorn and others. They looked at 62 beef herds in the north island of NZ. Resistance is defined as less than 95% reduction in worm egg count (WEC) after treatment.

Given that worms cost you so much money, probably a whole lot more than you realize, it’s important to control them effectively, right? For sheep and goat producers, you almost certainly have resistant worms on your farm. Cattle producers need not be smug: your turn is coming. And, I reckon that 90% or more of you don’t precisely know what resistant worms you have – that is, exactly which drenches work on your farm, and how well.

Table 2 – Percent of beef cattle farms with resistance, NZ North Island * B

"  


   

* 

  

H0

0

28

There is probably no drench on the market in Australia that is not affected by resistance. But how common is resistance to the various drenches? Here is a thumbnail sketch.

 

 

60  9

11

2

2

;  

6+ !$ 9

3-

.

@

Table 1 – Percent of Australian sheep farms with resistant worms (approx.)


   

69

H0

.

28



2.

; B  B 6%  '& %;E'9

2.

)    6)"& %  '9

Of course, these NZ results can’t be extrapolated to Australia, but we are likely to have a lot more resistance in cattle worms than previously thought. We do after all use drenches a fair bit, sometimes in ways that tend to promote resistance, for example, frequent treatments of ML products to control cattle tick, and unnecessary treatment of adult animals.

 !" #

"   6%"D/'9

;E"D/   



0.!C.

F  C.G

10

OK, that’s the doom and gloom, what can you do? Here are simple things sheep, cattle, and goat producers can do to lose less money: •

• • •

•

• •

Know your drenches. Do a DrenchTest (a faecal egg count reduction test). This is like a mini-trial on your farm. More simply, do regular DrenchChecks. Generally this just involves a worm egg count (WEC) 7–10 days after using an anthelmintic. WEC is your friend. WormTest often. Avoid unnecessary drenching, especially of adult animals. Use effective drenches. Consider using combination drenches, products combining unrelated broad-spectrum anthelmintics. Rotate drenches, whether annually or otherwise. In sheep this might mean rotating between ML and non-ML based combinations.

•

Use an effective quarantine drench. You don’t need someone’s resistant worms. Practice IPM: good genes, good food and rotational grazing as well as the right drench at the right time can mean more profit and better animal welfare. Avoid drenching when there are few worms on pasture, for example during drought or prolonged dry spells.

Further information: ƒ Wormboss (www.wool.com/womrboss) ƒ MLA website (www.mla.com.au) ƒ Turning the Worm (TTW) Issues 11, 12, and 22. (www.dpi.nsw.gov.au/aboutus/resources/p eriodicals/newsletters/turning-the-worm) ƒ Livestock Health – Industry & Investment NSW website (www.dpi.nsw.gov.au/agriculture/ livestock/health) ƒ New Zealand Veterinary Journal, December 2006. (Summarised in TTW Issues 22).

Advertisement

11