I find it interesting that Mississippi State University actually provides clear instruction to incorporate these anthelmintics into the feeds, right down to the specifics as to the amounts (click the Solutions Used for Poultry link below, in my signature ~'-)
SoOo ... to clarify the 'legality' of "extralabel" use of the anthelmintics ... and, more importantly, provide the informations about the five choices vet's have for prescribing, read on:
AMDUCA Allows for Alternatives
The Animal Medicinal Drug Use Clarification Act (AMDUCA), issued by
FDA/CVM in 1994, allows the veterinarian to prescribe certain drugs in an extralabel fashion.
“Extralabel use of a drug may include a route, dosage, duration, frequency, indication or species not included in specific product labels” (1). AMDUCA permits extralabel use when an animal’s health is threatened or the animal is suffering. A veterinarian may use a drug approved for a food animal, in an extralabel manner, if he or she has determined there is no approved animal drug for such use that contains the same active ingredient in the required dosage form and concentration. The practitioner must take steps to make a diagnosis, establish a substantially extended withdrawal period, assure the identity of treated animals and assure that time frames for withdrawal are met so that no illegal drug residues occur. Veterinarians can meet their responsibilities regarding withdrawal by adequately informing their clients. Maintaining a record of prescriptions written, with detailed instructions on use as part of the script, is advisable. Dr. Elizabeth Curry-Galvin, DVM, Assistant Director of the Scientific Activities Division of the American Veterinary Medical Association states that “The AMDUCA final rules include a provision for approved animal drugs that, in certain circumstances, are judged ineffective. When, in a particular case, a veterinarian judges an approved drug to be clinically ineffective for its intended use and the practitioner has a basis for coming to this conclusion, extralable use of that drug or another approved drug is allowed” (2). In the case of piperazine, this interpretation allows a veterinarian to recommend a use rate of piperazine higher than the label indications, or to substitute another wormer if he/she has met the above criteria. Once again, establishment of an extended withdrawal time based on the label for other species and other available data is required of the practitioner when prescribing extralabel in a food animal species.
NOTE: A review of AMDUCA, 21 CFR, Part 530, Final Rule is recommended.
Treatment Alternatives
1. Tramisol
(Active ingredient: Levamisole hydrochloride) - Schering Plough.
Soluble Drench Powder approved in sheep, cattle, and pigs. Withdrawal for cattle is 48 hrs
pre-slaughter, 72 hrs pre-slaughter for sheep and 72 hrs for pigs. Levamisole will not settle out in
medication lines. Chicken and turkey dose is 16 mg active levamisole per pound of body weight
delivered by proportioner over 3-4 hours as a bolus for capillaria and cecal worms in pullets and
hens. There is no effect on hatch, egg production, feed conversion, or body weight when used at 8
and 16 mg/pound of body weight dose. However, in the chicken, at 36 mg/pound, water intake is
reduced, at 288 mg/pound, diarrhea occurs, and at 900 mg/pound, 20% mortality occurred. Egg
residue clearance time is not known. For roundworms in broilers/pullets, the dose is 8 mg of active
levamisole per pound of body weight. This is given as a bolus over 3-4 hours. Tissue withdrawal
times and egg withdrawal times must be extrapolated and extended for safety based on data from
approved food animal clearances (3,4,5,6,7,8).
2. Valbazen
Oral Suspension (Active ingredient: Albendazole) - Pfizer Animal Health
Albendazole has been reported to be effective in the treatment of capillaria, ascaridia, heterakis, and
tape worms in chickens. It has been labeled only for cattle and sheep. There is no poultry data
available. Settling in drinker lines has not been reported as has been seen with other anthelmentics in
this class. Cattle require a 7 day withdrawal and sheep require a 7 day withdrawal pre-slaughter.
There is no available data on tissue or egg clearance time in poultry. There have been no reported
negative effects on the performance of broilers, pullets and hens. Valbazen is supplied in 500 ml,
1 liter, and 5 liter bottles of an 11.36% suspension. In chickens, the reported dose is 10 mg/kg of body
weight (personal communication).
The cattle dose is 1 liter of Valbazen 11.36% Suspension per 500 lb as an oral bolus via dosing gun
or dose syringe. (4.54 mg albendazole/lb, 10 mg/kg). Sheep dose is 1 liter of Valbazen 11.36%
Suspension per 664 animals weighing 50 lbs each (3.4 albendazole/lb, 7.5 mg/kg).
3. Synanthic
Bovine Dewormer Suspension, (Active ingredient, 22.5%: Oxfendazole) -
Fort Dodge Animal Health
Synanthic is reported to be effective for capillaria, ascarids, and heterakis. Synanthic does have
activity against cattle tape worms, however, there is no data whether it will work against poultry
tapeworms.
There is 225 mg oxfendazole per ml and it is supplied in a 500 ml bottle for cattle. The
withdrawal time is 7 days for cattle. There is no tissue-clearance data available for poultry, nor any
data available on side-effects in poultry. The cattle dose is 2.05 mg/pound of body weight
(4.5 mg/kg B.W.). There is also a 9.06% suspension available in a 1 liter bottle (90.6 mg/ml of
oxfendazole). Settling out in water lines without agitation can be a problem (personal
communication).
4. Safe-guard (Active ingredient: 10% suspension, Fenbendazole) - Beef and dairy cattle,
oral parasiticide - Hoechst-Roussel
Effective against capillaria, round, and cecal worms in chickens (not approved in chickens). It is
approved for turkeys as a feed additive, 20% premix type A and B, 16ppm (14.6 gm/ton complete
feed for 6 consecutive days) for control of adult and larvae round worms and cecal worms.
The cattle dose is 2.3 mg/pound BW (5 mg/kg BW) as an oral bolus. Beef cattle withdrawal is
8 days following the last treatment. For dairy cattle, there is no milk withdrawal time. Safe-guard
is supplied in 1 liter and 1 gallon bottles. There may be a problem with settling out in drinker lines
without agitation (personal experience).
5. Ivermectin (1% injectable for cattle)
Since Ivermectin went off-patent, there are several manufacturers producing it. Ivermectin has been
used orally via extra-label scripts to treat Northern Fowl Mite and capillaria infestations. Only mites
that are on the birds are killed. The 1% injectable cattle formulation has been used as follows
(personal communication):
• 1 ml of 1% Ivermectin injectible + 1 ml. propylene glycol + 2 gal H2O, proportion at 1
oz./gal D.W.
• Administer 2 times, 10-14 days apart. There is a 30 day withdrawal (destroy commercial
eggs for 30 days post-therapy.)
* As Published by the Department of Avian Medicine, University of Georgia
OK, ok ... movin' on ...
