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Anthelmintics Effective deworming programsmall ruminants • Deworm ewes shortly before, or right at, lambing. – best opportunity to disrupt the parasites' cycle in flocks – ensures a low parasite burden when ewes are turned out on grass – late lambing ewes should be treated twice with an anthelmintic. Effective deworming programsmall ruminants • Deworm on grass. – Larvae in the pasture can overwinter – Deworming sheep or cattle on pasture is done when moderate to high parasite burdens in the pasture are anticipated – Deworming is done about three weeks after turnout on grass. It can be continued at intervals, depending on parasite exposure and risk Effective deworming programsmall ruminants • Reduce pasture contamination. – Reducing the numbers of larvae eaten is a primary goal of any control program – If possible, mechanically harvesting spring grass will eliminate a large percentage of infective larvae, which die as hay is cured. – Yearly rotation of pasture using other species, such as horses, helps break the parasitic cycle since there is little infective crossover of worm species. Haemonchus contortus is an exception if cattle and sheep are alternated; Effective deworming programsmall ruminants • Treat and move. This approach involves movement sheep and pairs, following worming, to fresh pasture or pastures where risk of exposure is low. • Fall deworming. – Animals that accumulated parasites during summer months can have their worm burdens markedly reduced. – spring and early summer preventive program is not used. – Diagnostic assistance such as fecal examination can be done to quantify the worm burden. Strategic deworming • Focus on the pasture – Wet grass – > 55 F – “While the grass is dry without dew or rain, the cattle do not get worms “ – When to deworm • when larvae are developing in the spring or fall • during inhibition of larvae in the summer before the larvae emerge in early fall • Cattle Endoparasites Helminths are divided into two major groups: Nematodes: cylindrical, nonsegmented worms commonly called roundworms Platyhelminthes: flattened worms that are subdivided into two groups: Cestodes (tapeworms) Trematodes (flukes) Anthelmintics Antinematodals Anticestodals Antitrematodals There are three families of drugs which are used to treat internal parasites in livestock: 1. Benzimidazoles - Fenbendazole, Albendazole, Oxybendazole, Thiabendazole 2. Nicotinics - Levamisole, Pyrantel, Moratel 3. Macrolytic Lactones - Ivermectin, Doramectin, Moxidectin Benzimidazoles • Work by interfering with energy metabolism of the worm • Recognize by –azole ending in drug name • Always read the label to determine which parasites a drug is effective against • All can be administered orally, either as a paste, a granulated powder, or a solution. • Side effects are rare with benzimidaloles, but may include vomiting, diarrhea, and lethargy. The Benzimidazoles • Safeguard®, Panacur®, Valbazen®, Synanthic®, also called "white dewormers" • broad spectrum and safe to use: ostertagiosis • They are effective against tapeworms • Albendazole is effective against adult liver flukes, but should not be used in pregnant or lactating females. Safeguard ® Panacur® liquid 10% Safeguard ® Panacur® paste Safeguard Pellets Synanthic ® drench 9.06% Valbazan® drench 11.36% Fenbendazole Fenbendazole Fenbendazole Oxfendazole Albendazole BZD cattle, nonlactating goats roundworms lungworms tapeworms 2.3 ml/100 lbs. by mouth cattle: 8 days slaughter 0 milk withdrawal goats: 6 days slaughter BZD cattle horses roundworms lungworms tapeworms 2.3 mg/lb. by mouth cattle: 8 days slaughter BZD cattle swine roundworms lungworms tapeworms 1 lb./100 lbs. by mouth swine: 14 days slaughter BZD beef cattle non-lactating dairy roundworms lungworms tapeworms 2.5 ml/110 lbs. by mouth cattle: 7 days slaughter BZD cattle sheep roundworms lungworms tapeworms adult liver fluke 3 ml/ 100 lbs. oral restricted during pregnancy sheep: 7 days slaughter Nicotinics • • • • • Levamisole (Tramisol®), also called a "clear dewormer“ broad spectrum and effective against arrested larvae narrower margin of safety, especially in the injectable form. Pyrantel (Strongid®) is only effective against adult worms. Moratel (Rumatel®) is an oral feed additive and is only effective against adult worms Imidazothiazoles Work by stimulating the nematode’s cholinergic nervous system, leading to paralysis of the parasite (therefore, not ovicidal) Effective against ascarids, strongyles, whipworms, and hookworms Was used as a microfilaricide in the past An example is levamisole (Levasol®) Expels most nematodes in 24 hours (some may be passed alive) Available in oral forms such as pellets, powder, suspensions, and pastes Also has anti-inflammatory and immunostimulant properties May cause toxicity in host animal due to cholinergic effects Prohibit Drench Powder Levamisole Hydrochloride cattle sheep TETR roundworms intestinal worms lungworms roundworms intestinal worms lungworms Depends on dilution Tramisol/L evasole® drench Levamisole Tramisol/L evasole® injectable for cattle 13.65% Levamisole IMID beef cattle roundworms lungworms 2 ml/100 lbs. Sub-Q cattle: 7 days Tramisol/L evasole® boluses/ob lets Levamisole IMID sheep roundworms lungworms 1 bolus/50 lbs. by mouth sheep: 3 days slaughter IMID sheep cattle 1 oz./100 lbs. 1 ml/50 lbs. by mouth cattle: 2 days sheep: 3 days sheep: 3 days slaughter Macrolytic • • • • • • The Macrolytic lactones or "avermectins" (Ivomec®, Dectomax®, Quest®, Cydectin®) newest family of drugs broad spectrum and have a wide margin of safety They are also effective against external (biting) parasites, including nose bots Moxidectin is a persistent-activity dewormer that continues to kill worms after it is administered. Drench for SHEEP! *!Approved Species Specificity NOT completemost common ONLY Labeled Dosage for approved species *Goat Dosage is Higher Withdrawal time for approved species Trade Name Drug Ingredient Drug Family Cydectin® 0.5% pour-on for cattle Moxidectin ML beef cattle non-lactating dairy cattle roundworms lungworms external parasites 5 ml/110 lbs. topical cattle: 0 days slaughter Cydectin® 1% injectable Moxidectin ML beef cattle roundworms lungworms external parasites 1 ml/110 lbs. cattle: 21 days slaughter Cydectin® oral drench for sheep 0.1% Moxidectin ML sheep Not for lactating dairy sheep roundworms lungworms external parasites 1 ml/11 lbs. by mouth or 1 ml/5 kg sheep: 7 days slaughter roundworms lungworms external parasites 1 ml/110 lbs. (cattle) 1 ml/110 lbs (swine) Sub Q or IM cattle: 35 days slaughter swine: 24 days slaughter Dectomax® injectable 1% Doramectin ML beef cattle swine Dectomax® pour-on for cattle 0.5% Doramectin ML cattle roundworms lungworms external parasites 5 ml/110 lbs. topical cattle: 45 days slaughter Eprinomectin ML cattle roundworms lungworms external parasites 5 ml/110 lbs. topical cattle: 0 days slaughter Ivermectin ML beef cattle roundworms lungworms external parasites 1 ml/22 lbs. topical cattle: 48 days slaughter Ivomec® Eprinex pour-on Ivomec® pouron for cattle Ivomec Plus Injection Ivomec® injectable 1% Ivomec® sheep drench 0.08% Primectin ™ Drench Quest® 2% equine oral gel Zimecterin -EZ® paste 1.87% Clorsulon Ivermectin Ivermectin Ivermectin Moxidectin Ivermectin ML ML ML ML ML beef cattle roundworms lungworms external parasites Adult liver flukes 1 ml/110 lbs. SQ cattle: 49 days slaughter beef cattle swine roundworms lungworms external parasites 1 ml/110 lbs cattle. 1 ml/75 lbs. swine Sub-Q cattle: 35 days slaughter swine: 18 days slaughter sheep roundworms lungworms external parasites 3 ml/26 lbs. by mouth sheep: 11 days slaughter horses ponies roundworms lungworms external parasites 0.4 mg/2.2 lbs. not for horses intended for food horses ponies roundworms lungworms external parasites 1 tube/1250 lbs. oral not for horses intended for food Economics - Sheep References • http://www.sheepandgoat.com/articles/ant heltable.html • http://www.uwyo.edu/vetsci/Courses/PATB _4110/2009_lectures/33_parasites_cattle_ sheep/HTML/Class_Notes.htm • http://extensionvetmed.blogspot.com/2009 /04/when-is-right-time-to-dewormcattle.html • http://vetpda.ucdavis.edu/parasitolog/Para site.cfm?ID=188
