Teagasc Grange’s Orla Keane discusses dosing cattle, herd health and parasite management and the usage of antibiotics and disinfectants.
According to Orla, The first essential component of the herd health plan is disease prevention.
Orla told Catherine Egan on Teagasc’s Beef Edge podcast:
“We all know prevention is better than the cure. Preventing animals from getting sick is better than having to treat them for the disease.”
“Good hygiene – proper cleaning, disinfection of pens, disinfection of boots, utensils and any instruments you are using – so ensure you have good footbaths at entry and exit points.”
Vaccination is another important aspect of disease prevention.
“Clostridial disease, respiratory disease, in consultation with your vet using vaccination where appropriate to prevent diseases is important and testing to know what diseases are present on the farm is important to prevent them.”
Orla believes that having a “closed herd” is the best way to avoid letting disease in.
“That is maybe not an option for some people, so if you are buying in: try to limit the number of sources you are buying from, try to buy from herds with a high known health status where you can.”
“When you buy in stock, isolate them for four weeks before you mix them with the home herd. All of these are key ingredients of a herd health plan.”
She said that farmers should clean out calving pens and sheds at this time of year.
“The first step is to remove all beddings material making sure you clean out the pens in the sheds well, removing dirt and dry faecal matter,” Orla advised.
She cautioned that some disinfectants will not work if organic material is present. Therefore, you must eliminate everything.
“Surfaces, equipment and fittings should be disinfected, then the sheds rinsed and left to dry.”
She feels that the longer the sheds remain vacant, the better because some pathogens may persist in the environment for extended periods.
“The longer they remain clean and dry, the better.”
She encourages farmers to discuss the right disinfection to use with their local vet or advisor as there are several disinfectants available.
“The Department of Agriculture, Food and the Marine’s website lists disinfectants that are effective against different types of pathogens.”
“It is important when you are disinfecting that you follow the correct instructions for the disinfectants that you use”, Orla stated.
“Disinfectants can differ in different ways. They might have to be diluted differently as some of them will kill some types of pathogens.”
She feels that the contact time, which may be many hours, is also very important.
“It is important that you check what the recommended contact time is, and you make sure you stick with that time”, Orla advised.
“Continuous use of antibiotics can lead to the development of antimicrobial resistance where the pathogens develop resistance to the antimicrobial used to kill them.”
“These are a threat, not just a threat to the animal health, but for a number of the pathogens, they are also a threat to human health.”
“There is an onus on everybody in human medicine and veterinary medicine to ensure that all antibiotic use is justified. It is prudent, so they are only used when necessary.”
She believes that now is a good time to review how the calving season went in terms of “trying to reduce antimicrobial use now, coming back to disease prevention by having good hygiene, good biosecurity, good housing and having the right stocking densities”.
All of these measures, including vaccination, when possible, will assist in reducing the dependency on antimicrobials.
As the stock are out at grass, many parasites will present a challenge.
“Gut worms and lungworms are also developing resistance to the drugs that we use to treat them. With the gut worms, by the time you clinically see resistance, it is quite far gone.”
“When the drugs are killing a large number of the parasites, but not all of them, you might not see that clinically; you will only see that by testing.”
Testing can be completed by using dung samples “before and after treatment for parasite eggs to ensure the parasites are killed”.
“Clinically, if you see no improvement after using the treatment, that will be an indicator of resistance.”
Faecal egg reduction and post-dosing faecal egg count
A post-dosing sample which is clean, “no parasite eggs, you do not know that is because the drug worked or because there were no parasites present at the beginning”.
Preferably, having a sample pre-and post-treatment, “you know that there were parasites there by eggs in the dung and after treatment, no eggs were remaining”.
“Individual sample testing tends to be expensive; most people do composite samples, pre and post giving a good indication whether the drugs are effective or not.”
“The definition set by the Association for the Advancement of Veterinary Parasitology says that there should be a reduction of 95% or more in the egg count.”
“When these drugs work, they are very effective at killing all of the worms.”
“You should be looking at a reduction of 95% or more. Composite samples with low egg counts can be harder to determine, but in general, when these drugs work, no eggs remain after treatment.”
In terms of the antiparasitic, there are two groups, the wormers, which target the stomach, gut worms, lungworms, and flukicides.
She warned that the major parasites this time of year are the gut and lungworm.
“The drugs that treat these parasites all fall into one of three classes.”
“These are benzimidazoles, commonly known as the white wormers, levamisole is commonly known as a yellow wormer and the macrocyclic lactones commonly known as the clear wormers.”
She feels that if you want to change the product you are using, it is “important that you change the class, not just the brand”.
“If a worm has resistance to one product in the white class, it will also have resistance to the other products in the same class.”
She advised that you should make sure you are “rotating the class and not just the brand name” if you want to rotate your treatment.
“Fluke is a problem later in the autumn in the winter. You are treating for fluke at a different time of year. Therefore, I would only use combination wormer flukicides if you are specifically targeting both parasites.”
“It is not that important whether you rotate annually or every second dose. The most important thing is to use one that is effective on your farm.”
“Parasites are ubiquitous; they are on every farm in Ireland.”
In Orla’s opinion, mixed grazing for farmers that have both cattle and sheep is an option for reducing the challenge as the parasites that infect sheep are different to those which infect cattle.
“The lung and gut worm parasites are different; the fluke is the same, so by mixed grazing with sheep that will reduce the challenge for each species.”
“Using the leader-follower systems where older animals follow younger animals can also help.”
“The older animals have immunity cleaning up some of the parasites left behind by younger animals.”
Reseeded ground or silage after grass will help reduce the worm burden.
Orla warned that treatment may be needed at some point.
“It is important that when that treatment is given, it is given appropriately to the right animals, at the right time and the right dose rate.”
Spring-born calves coughing
Orla believes the main issue to keep in mind at this time of the year is lungworm in calves.
“People might recognise the signs of hoose if they see it. There may be other respiratory pathogens out there that will also cause coughing.”
Without testing, it is difficult to be certain what the main cause is.
“One possibility is to treat the calf herd with an anthelmintic that is effective against lungworm and monitor and make sure there is an improvement, and if there is not, then further investigation with veterinary guidance would be required.”
She stated that the main thing to keep in mind at housing for the stomach worms is “the products are effective against different stages except for Levamisole”.
“Levamisole is not effective against very early infections.”
“If you are using Levamisole at housing, you need to give it a week or two after housing. The other two products, the white and the clear, you can give at housing.”
“When it comes to flukicides, generally, they would need to be treated at housing and again maybe six to seven weeks later depending on the product.”
“What is the challenge out there at the moment? is the main thing farmers should be asking.”
“What are they trying to control? Is that product a suitable product to control the pathogen that they are looking to control?”
“So that is the most important question at this time of the year,” Orla concluded.
Find out more about dosing cattle by listening to this episode of the Beef Edge podcast
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