Topic of the Week - Deworming chickens

[casportpony]

@Isay Willow , thanks for the link. It sure seems like it's worth doing more research, but the study doesn't say that it kept any of the hens parasite free, and that's what so many people think it does. Heck, I was one... I bought a huge bag of the food grade stuff and I put it everywhere, as in every square inch of their 10' x 20' coop, and all the spots in the yard where they dust bathed. Thought I was covered until one day I checked a hen and she was covered in lice! So then I dusted her from head to toe and rechecked for the next 3 days and that was no appreciable change.

-Kathy

 

[casportpony]

More on DE: http://www.the-chicken-chick.com/2012/05/diatomaceous-earth-de-benefitrisk.html

-Kathy

 

[casportpony]

This was written for reptiles, but much of it still

applies to avian medicine.



http://www.reptilesmagazine.com/Rep...es-Nematode-Parasites-Treatment-Fenbendazole/
Reptiles Nematode Parasites Treatment: Fenbendazole

BY ROGER J. KLINGENBERG

Nematodes are among the most common parasites diagnosed in reptiles, with more than five hundred reptile forms identified. Larval forms migrate through the body. Adult nematodes are typically thought of as worms. Because of their ubiquitous nature, several drugs have been adapted to treat them.
Fenbendazole is a member of the benzimidazole group of anthelmintics, which also includes thiabendazole (TBZ), mebendazole (Telmin), and albendazole (Valbazen). This group of anthelmintics has been widely used in veterinary medicine because of their effect not only on mature worms but also on larval and even encysted stages. In addition to killing mature worms, the benzimidazoles exert an ovicidal effect, immediately decreasing egg production by effectively sterilizing the worm.
Although literally hundreds of benzimidazole derivatives have been formulated, fenbendazole is easily the drug of choice among the variations. While all medications in this group are considered to be very safe, fenbendazole is the safest of all of them. It was difficult to establish an LD50 (lethal dose at which 50 percent of test population will perish) in rodents. Even a dose greater than ten thousand times a normal dose would not consistently kill mice or rats. In addition to its excellent safety record, fenbendazole does not cause birth defects, unlike most of the other drugs of this group. The only contraindications for the use of fenbendazole are its uses in horses to be used for food and in lactating cattle. There are no proven reptile contraindications or known drug interactions.

Fenbendazole functions by inhibiting the uptake of glucose (sugar) in the nematode parasite. This block of glucose uptake is slow, so fenbendazole works better when given over a course of several days than in single or multiple doses that are given at spaced time intervals. Fenbendazole is the drug of choice for nematode parasites and is given orally at 25–50 mg/kg once daily for three to five days and then repeated in ten days, if warranted. If used for giardia infections, it should be given at 50 mg/kg daily for five days.
Upon oral administration, fenbendazole is minimally metabolized, and the majority of the drug is excreted unchanged. This helps explain why the cloacal administration of fenbendazole (Innis 1995) is effective only with parasites found in the cloaca and will do nothing for parasites in the remainder of the GI tract. In his report, Innis describes how he initially gave a tortoise fenbendazole at 100 mg/kg orally once and then again two weeks later, and the pinworms were not eliminated. He reported better results with dosing the fenbendazole with a syringe into the cloaca. We now know that had Innis administered the fenbendazole orally over a course of three to five days, it would have produced even better results as a result of the constant blockage of glucose uptake in the worms. In any case, it is interesting to have another route of administration because it isn’t always easy to get oral fenbendazole down a tortoise for three to five days.
The technique that Innis employed was to place the tortoise in dorsal recumbency (upside down) and, with the drug inside a tuberculin (1 mL) syringe with a lubricated tip, introduce the syringe into the cloaca. Although it is beneficial to place the medication as far into the rectum as possible, care should be taken to advance no more than half of the syringe and to stop immediately if resistance is noted. Leakage is prevented by manual pressure on each side of the cloaca. Innis further reported an almost immediate expulsion of pinworms due to the enema effect. The pinworms continued to be passed for another two to three days. He also suggested using a red rubber urethral catheter in larger specimens to prevent depositing the drug into the bladder. Again, although cloacal administration of fenbendazole will produce results, it is not as effective as the oral administration because the drug’s action is limited to the colon. Regardless of the route chosen for administration, the drug is best given over consecutive days, rather than in individual, spaced doses.
Some reptile veterinarians believe that albendazole is more effective in single doses than fenbendazole is. Even if single dose effectiveness is conceded, fenbendazole is preferable for several reasons. Although albendazole is considered to be safe, it is better absorbed than the other benzimidazoles are, which increases side effects with the liver and hematologic organ systems. Both drugs are more effective when administered daily for several days rather than in one dose, so single-dose effectiveness is a moot point. Albendazole is also teratogenic (causing birth defects) and embryotoxic (causing damage or death to the embryo), which would pose an undue risk for potentially gravid animals. Finally, albendazole interacts with praziquantel (Droncit) and dexamethasone, which would limit concurrent treatment of cestodes. Fenbendazole is simply safer than albendazole.
This author has been jokingly accused of owning stock in Panacur as a result of such enthusiastic promoting of fenbendazole. So to provide a balanced argument, let’s discuss some downsides of fenbendazole. As mentioned previously, the drug was implicated in the deaths of four Fea’s vipers. Stein and Wynne (G. Stein and J. Wynne 1993, pers. comm.) noted that tortoises treated with fenbendazole became anorexic but regained their appetites after a few days. The author has noted that bearded dragons can go off food dramatically when put through consecutive day dosing, with the longest period of anorexia being two weeks. As bearded dragons often have both pinworms and coccidia, it is not unusual for them to be treated with both sulfadimethoxine (Albon) and fenbendazole at the same time, leading to questions about which drug could be causing the appetite to be suppressed. In any case, both drugs have caused appetite suppression when used separately, so perhaps a noncritical bearded dragon should be treated in stages to minimize appetite disruption. For bearded dragons that won’t eat, force-feeding appears to kick-start most into eating again. Employ force-feeding early and continue force-feeding until the dragons feed on their own.
In some rare cases, parasites appear to be resistant to fenbendazole. In this situation, the author suggests using ivermectin, which may require more doses over time. A small study (Klingenberg 1993) demonstrated this in ball pythons. Fenbendazole eliminated nematodes in fewer doses than ivermectin did (see appendix III). Corwin (M. Corwin 1994, pers. comm.) reported that this was also true when treating nematode parasites of monitor lizards.
Excerpt from the book Understanding Reptile Parasites by Roger Klingenberg with permission from its publisher, Advanced Vivarium Systems, an imprint of BowTie Press. Purchase Understanding Reptile Parasites here.

-Kathy

 

[rebrascora]

Personally I think it is unreasonable to expect to keep poultry or any other outdoor creature. pest/parasite free.

We live in such a sterile obsessed society that the thought of worms, germs and bacteria are horrifying to us and we have been conditioned into believing that finding any on our birds/animals is very bad, so we routinely throw chemicals into their system in the hope of keeping them parasite free. What we should be more accepting of is a base level of infestation so that there is a balance between pest and host and only intervening when the balance has tipped too far. Getting faecal worm egg counts done helps you come to terms with there being worms there but only treating when the count is on the high side. I'm not saying that I don't love getting a "<50 eggs per gram...No eggs seen" result but if it's a low to medium count that just means I need to monitor condition until the next count.... not get into Darlek mode and "Exterminate".
Nature is profligate and of the thousands of worm eggs that are shed, very few are successful in being ingested and completing their life cycle. Just like a tree sheds thousands of seeds but very few germinate and even fewer develop into saplings and fewer still of those grow into trees.

It's easy to find a worm in a poop and panic, but if you accept that there will be worms in your chickens/dogs/horses etc, then surely that is to be expected every once in a while. Seeing them more frequently than the occasional one or the animal losing condition and looking off colour is the time get it checked out and deworm if necessary.

Interesting research result on DE. Many thanks to @Isay Willow for posting it.

 

[casportpony]

So there are many posts that say Safeguard should not be during molt, but that Valbazen can be used, but I haven't seen any properly documented studies or literature that say this is true, but I did find this:

Quote: Source: http://www.auspigeonco.com.au/Articles/Race_Form_Part3.html

So that would mean no Safeguard, Valbazen, Wormout Gel, etc.

These are fret marks






-Kathy

 

[Kay Kew]

More on DE: http://www.the-chicken-chick.com/2012/05/diatomaceous-earth-de-benefitrisk.html

-Kathy

Some interesting aspects raised in that article - I think the consideration of what effects our chosen methods of treating (and feeding) our domestic animals and pets may have on the wider environment / biodiversity is a really important one. Many years ago I took a course in canine behaviour and training and met many interesting people who were obsessed with dogs!! It struck me as somewhat strange that people who clearly absolutely adored their dogs and would do anything for them, seemed not to be concerned in the slightest about the origins of the food they were giving them, except in so far as it affected the dogs. Similarly a work colleague of mine once reported, with obvious astonishment, that she knew of a woman who specifically sourced free range poultry meat to feed to her dogs. It didn't seem to occur to her that perhaps the woman in question had some thought for the welfare of the animals being eaten as well as the ones doing the eating!!

I was also interested to see the reference to parasite resistant breeds in the reference provided on the efficacy of DE. How do Light Sussex bantams rate on that score I wonder?

 

[casportpony]

Personally I think it is unreasonable to expect to keep poultry or any other outdoor creature. pest/parasite free.

We live in such a sterile obsessed society that the thought of worms, germs and bacteria are horrifying to us and we have been conditioned into believing that finding any on our birds/animals is very bad, so we routinely throw chemicals into their system in the hope of keeping them parasite free. What we should be more accepting of is a base level of infestation so that there is a balance between pest and host and only intervening when the balance has tipped too far. Getting faecal worm egg counts done helps you come to terms with there being worms there but only treating when the count is on the high side. I'm not saying that I don't love getting a "<50 eggs per gram...No eggs seen" result but if it's a low to medium count that just means I need to monitor condition until the next count.... not get into Darlek mode and "Exterminate".
Nature is profligate and of the thousands of worm eggs that are shed, very few are successful in being ingested and completing their life cycle. Just like a tree sheds thousands of seeds but very few germinate and even fewer develop into saplings and fewer still of those grow into trees.

It's easy to find a worm in a poop and panic, but if you accept that there will be worms in your chickens/dogs/horses etc, then surely that is to be expected every once in a while. Seeing them more frequently than the occasional one or the animal losing condition and looking off colour is the time get it checked out and deworm if necessary.

Interesting research result on DE. Many thanks to @Isay Willow for posting it.

If I pick up a hen and she has a few lice that doesn't bother me, but when I pick up one that's covered in them, it's time to treat. Mites are different... The red mite feasts on the bird at night, so unless you check your birds at night, it's unlikely that you will see any. Since mites drink blood, I have a zero tolerance for them, so if any are seen, coops perches, and birds are treated, period

Fecal egg counts... I know there is protocol for when to treat, but how many people will have fecals done to know if they should treat or not treat? And what about false negative fecals? A friend of mine had a hen on deaths door and took a poo sample in for a fecal, and that fecal was negative, so she figured it had to be something else. Would it surprise you to know that two days later they did another fecal and that bird had a severe infestation of capillary worms *and a severe case of coccidiosis?


-Kathy

 

[casportpony]

Quote: Parasite resistance is interesting, and something I know very little about.

-Kathy

 

[casportpony]

Parrot with a very high fecal egg count:




Perhaps Macaws are less resistant to parasites than chickens?

-Kathy

 

[Kay Kew]

http://www.tandfonline.com/doi/citedby/10.1080/00071666808415695?scroll=top&needAccess=true

Here's the start of my investigations along that line! And the fact that I think I have managed to post a link to something is my achievement of the day!