Friday, April 19, 2024

Cooperia in healthy cattle

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The importance of drenching against Cooperia is well known in young cattle. In extreme conditions Cooperia can cause thin, scouring weaners that can die if not treated quickly. That was thought to be the extent of the disease, however, recent work has shown that seemingly healthy R1 cattle are also affected. If you are using the wrong drench this could be costing you money. There are three main species of cattle parasite of primary importance in cattle. Ostertagia is often referred to as the parasite of main concern, followed by the Trichostrongylus species. Cooperia parasites need to be present in much higher numbers to cause disease. Until recently it was generally presumed that loss of production wouldn’t occur until severe worm burdens were present. Dry seasons such as this will favour all parasites when autumn rain comes. Grazing animals’ natural immune defences are weakened by drought and they are forced to graze low where the parasite larvae live.
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A wave of larval contamination can occur after a long dry spell and young cattle need to be drenched soon after decent rain.

The mectin drenches (endectocides such as abamectin, moxidectin, ivermectin, doramectin) now struggle to kill Cooperia effectively when used on their own. Fortunately, levamisole has excellent efficacy against Cooperia so using these drenches in combination makes perfect sense. The message of using combination drenches that contain levamisole has been well advised for years, especially in cattle under 15 months. Around 12-15 months the immunity of cattle against Cooperia is normally well established.

Dave Leathwick and others at AgResearch have shown recently that oral drenches provide superior Cooperia efficacy compared to pour-ons and injectables.

One disadvantage of oral combination drenches is the short drench interval of around four weeks. It has been tempting in the past to drench cattle with products with persistent activity that can stretch the drench interval to four to eight weeks.

Some care is required with products with a persistent claim. This claim is normally for only one parasite, namely Ostertagia.

In addition, this claim was based on information on the cattle parasites present when the product was launched. Through drench selection and parasite resistance on your farm, this length of drench persistency could be less than that claimed.

In addition, when treating Cooperia with levamisole, there are no persistent products available. Therefore an adult worm burden of Cooperia can re-establish in one worm life cycle, normally around three weeks after drenching.

In a study published in 2012, four drenches were tested in a standardised faecal egg count reduction test (FECRT) in 200kg R1 Friesian bulls on an intensive bull farm.

Three of the drenches contained levamisole in combination whereas one drench contained a single mectin  – doramectin (Dectomax).

The other drenches were eprinomectin and levamisole injection (Eclipse E), a BZ/Lev oral (Oxfen C Plus) and BZ/Lev/Aba oral (Matrix C).

Four groups of 15 bulls were treated with these four different products and weighed at days 0 and 32 and 63 post-treatment.

There was no surprise that there were Cooperia resistant to the drench without levamisole. What was surprising was the weight difference between the groups.

Normally, to achieve a statistical difference between groups large numbers are required. What is surprising in this instance is that there are only 15 bulls a group. These findings suggest that even relatively low levels of Cooperia in healthy nine-month cattle might have a detrimental effect on growth.

With the introduction of NAIT and mandatory EID tagging we now have the ability to quickly and accurately record treatments and individual weight changes within mobs. Dose response studies on your own farm should be done regularly, ideally with many more than 15 cattle.

You may determine which product is giving you the best return and identify early signs of drench resistance on your farm. You could then take this information to your vet and in conjunction with FEC and larval analysis plan cost-effective strategic and sustainable parasite control.

A full copy of the study is in the Sheep and Beef Cattle Veterinarians December 2012 Newsletter. If you are interested in learning more perhaps ask your enthusiastic cattle vet for a copy. 

  • Jeremy Leigh is a veterinarian at Anexa Health, Huntly.
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