Dosing cattle - habit or necessity?

Aidan Murray, Teagasc Beef Specialist, offers advice on dosing and questions do farmers need to change their dosing practices.

As we near the end of May with stock out grazing, there is something very satisfying about seeing cattle clean up, stretched out and thriving on good grass. At the same time, we are always looking for the one that doesn’t seem to be quite doing, one with a dirty tail or the sign of that first cough.

If we see that poor thriver or hear a few coughs, we immediately think about dosing. But we need to ask ourselves is it really necessary or can I hold off for a bit?

The reason I urge caution is that currently we only have three drug classes available for worming cattle. At this stage, we have varying degrees of resistance showing up across all three classes so the clock is ticking. We either rethink our use of anthelmintics, be more strategic in their use, or otherwise we increase resistance and the consequences it brings with it.

So a more planned approach to dosing is needed in terms of animal type, parasite to be controlled, product use/rotation and risk factors.

Animal type: Not all animals will be challenged to the same degree at the same time. For example, spring-born suckler calves will not be as exposed at this time of year compared dairy-bred calves. Older animals may have built up a level of resistance to some parasites.

Parasite to be controlled: Stomach worms, lungworms and possibly coccidia will be the parasites to monitor over the summer months. Liver fluke may be more prevalent in autumn and winter.

Product use/rotation: Are you a creature of habit and continually use the same anthelmintic class? It is good to rotate and mix things up when choosing a dosing product and, as I mentioned earlier, some groups are showing lower levels of resistance than others.

Risk factors: Weather conditions can accelerate or delay the rise in worm burdens; no two years will be the same as to when animals are severely challenged. Is there mixed grazing on the farm? Do you operate a leader follower system? How do you handle bought in animals before they are mixed with your own stock? Can you give the cleanest pasture to the most naïve stock?

Using Faecal Egg Counts (FEC)

It is important that you make use of available information or your herd history. Make a point of talking to you vet about when and what you should be dosing. Use Beef Health Check reports and definitely consider faecal sampling.

Anyone who participated in the BEEP S scheme will have a level of familiarity with taking faecal samples. But using FEC with young stock can often give you the proof or confidence you need to consider dosing. In calves, a faecal egg count of more than 200 eggs per gram may indicate a need to treat for gut worms. Other farmers that have used faecal sampling have identified problems with coccidia, which they didn’t realise was there.

Faecal egg counts can:

• Monitor gut parasite levels on the farm;
• Help diagnose a problem with sick or animals showing a lack of thrive;
• Determine if a group of animals need to be treated;
• Test bought in animals before mixing them with your own stock;
• Check if a resistance problem is developing on your farm.

There are a few pointers to stick to when faecal sampling, including:

• Wear protective gloves;
• Always ensure faecal samples are fresh and are from different animals;
• Place the same amount of faecal material in each sample pot;
• If samples are being collected in the field, it is much easier if the animals have been lying down as the will tend to defecate more once they get up;
• Worm eggs are not distributed evenly throughout the dung pat, so it is important to collect the sample from three different areas in the dung pat;
• Ideally you should look to collect 10 individual samples from at least 10 different animals. These samples can then be pooled by the lab;
• Sample pots should be placed in a zip lock bag and a submission form for the lab completed. Samples can be posted to the lab or left in with the local vet;
• Do not leave samples lying around for more than 24 hours. Avoid storing them in the freezer, fridge or in direct sunlight.

Worm control is just another one of things that we need to put a bit more thought and planning into. Thankfully we have options. At the end of the day, we should dose because we are confident that it is needed not because we have got into the habit of doing it.

Also read: How's the breeding season progressing for Future Beef Programme farmers?