David D. Frame Douglas Anderson and Mark C. Bland This chapter will address multiple issues and on‐farm decisions that a veterinarian must address when working with gamebirds in the field, including how to conduct a field investigation; how to appropriately medicate and vaccinate gamebirds; and, finally, how to use the diagnostic services that are available for medical practice with gamebirds. It is important to keep in mind that field investigations deal with a flock problem; therefore, the investigation by definition becomes an exercise in population health management. There are a number of components that can make a field investigation challenging. These consist of management practices, environmental factors, feeding and watering issues, and presence or absence of disease agents. The interaction among these variables can be complex. For this reason, it is important to ask relevant questions and make keen observations in order to get a clear understanding of the situation. Note taking during the farm visit may later prove to be invaluable. Typically, a request for an on‐site visit is initiated by the flock owner. During the initial visit, interacting with the owner and asking relevant questions will help increase perspective. An accurate and complete case history will go a long way in gaining an understanding of the problem. Although not exhaustive, Table 9.1 provides a checklist that may be a reasonable starting point. A good way to look at management and environment is to use a mental checklist such as FLAWS. This is an acronym that represents F for flock and feed, L for lights and litter, A for air (ventilation), W for water, and S for sanitation and [bio]security. See Table 9.1 for a fundamental checklist based on FLAWS. Table 9.1 Checklist for field visit observations. Although diseases and abnormalities of gamebirds are discussed in other chapters, the presence or absence of typical clinical signs will help in identifying potential cause(s). Field observations may reveal depression typified by ruffled feathers, inappetence, and reluctance to move. Respiratory signs of snicking or labored breathing may be present. Ambulatory issues, such as limping, paralysis, or abnormal joints, might be observed. The following describes basic equipment to have with you so that you can adequately examine birds while on the farm. Personal protective equipment (PPE) should include clean reusable or disposable coveralls, disposable bouffant (head covering), plastic disposable boots or rubber pull‐over boots, disposable gloves, heavy‐duty plastic garbage bags, hand sanitizer, and aerosol disinfectant. Necropsy tools consist of a sharp boning knife, scalpel blade (#10 BP), necropsy shears, several small and large scissors (sharp/dull tip), and mouse‐tooth forceps. It is highly recommended that a microscope with slides and coverslips be brought along to examine intestinal scrapings. For sample collection, bring a transportation crate (for transporting live/dead birds to the diagnostic laboratory), 3 cc syringes, with 20‐ and 22‐gauge × 1 in. needles, 1.5 mL microcentrifuge tubes or 5 mL red‐top blood tubes, several sizes of whirl packs, small specimen containers with and without formalin, and sterile swabs The objective of the field necropsy is to provide information that can be combined with flock history and field observations that will help to determine causes of performance problems, morbidity, and/or mortality. When necessary, euthanasia methods should follow AVMA guidelines [1]. The preferable protocol is to use CO2 gas using a small chamber or garbage can. Cervical dislocation can be employed as an alternative if no other recourse is available. The disadvantage of cervical dislocation is that the tissues in the neck are disrupted, thereby potentially hindering accurate assessment for potential upper respiratory or alimentary tract abnormalities. The necropsy technique of gamebirds in the field can vary, but it is imperative that one proceeds in an orderly fashion. This will reduce the chance of overlooking something. The necropsy procedure is described in detail in Chapter 15. Field necropsy should be backed up with appropriate laboratory diagnostic investigations on whole birds, tissue samples, serology, feed, and environment samples. Years ago, things were easier for the gamebird grower. Treatment of a mortality issue could be quickly solved with an antibiotic in the feed or water. Minimum tonnage requirements made it quick to change. There were numerous antibiotic options available and if these were not suitable, water‐soluble therapies were also readily available. Drugs might be used in combination or in off‐label levels. Drugs not intended for poultry could find their way into the feed system or drainage system as runoff to nearby water sources. Attention might be given to medication withdrawal times, or these withdrawal times might be ignored or interpreted incorrectly. In more recent times, some of the issues are the same. For example, feed versus water, drug resistance/sensitivity, and off‐label drugs/usages are important considerations when treating a flock. Although still considered poultry, gamebirds are often fed and watered in different manners. Netted outdoor flight pens might have a water system that will not permit the use of a proportioner, stock barrel/bulk tank, or water line, so there would be no way to get medicated water to them. Increasing ambient temperature may result in overconsumption and toxicity of certain sulfa drugs. Brooding rooms and dark houses should have a system that can supply medicated feed or water. Newer methods of administering medication include selecting an appropriate feed antibiotic with a VFD (Veterinary Feed Directive) or a water‐soluble antibiotic prescription (Rx) label as well as a source [2]. For example, salinomycin has a legal level, but some mills will refuse to carry the product because of its toxicity to horses. Farm stores used to carry many of the water‐soluble antibiotics over the counter (OTC), but since the 2017 deadline for VFDs and Rx, they now require veterinary oversight (Table 9.2). It is important to select the right product to provide the most judicious use of medication in order to prevent drug resistance [3]. Federal directives that provide oversight over the use of drugs by veterinarians are described below. Extra‐label drug use is any alteration of the drug label in dose, frequency, concentration, species, etc. No ELDU is permitted in the feed. The VFD must follow the label. This Act, instituted in 1994, addresses ELDU by veterinarians. It allows veterinarians to prescribe ELDU when the health and welfare of an animal are threatened or when suffering or death may result. It requires a valid VCPR (veterinarian–client–patient relationship). The veterinarian determines if a script is necessary. Only FDA‐approved drugs are permitted and must be intended for prevention, treatment, or control. They are not permitted if the drug results in an illegal food residue and cannot be used for ELDU in medicated feed. In an attempt by the FDA to eliminate the use of low‐dose antibiotics with medically important antibiotic usages (critical in human medicine) for the purpose of growth promotion and feed efficiency, the VFD was developed. Further, the goal was to place the remaining drug use under the supervision of a licensed veterinarian. A VFD can only be issued by a licensed veterinarian with a valid VCPR. In discussion with the client, examination of the patient/environment, and if available for followup care, the veterinarian accepts responsibility. Antibiotics can be used for prevention, control, and therapeutic purposes but not asgrowth promotants or for feed efficiency. Coccidiostats are not affected by the VFD. See the VFD form (Figure 9.1) for the required information. Figure 9.1 Veterinary Feed Directive. The VFD form provides veterinarians in all states with a framework for authorizing the use of medically important antimicrobials in feed when needed for specific animal health purposes. The VFD is written by the veterinarian and a copy is given to the feed mill and to the client. The Directive must be maintained for two years. This Act was instituted in 2004 to give veterinarians access to drugs that are not otherwise available. Minor use is for limited usage (infrequent, small numbers) in major species (horses, cattle, dogs, cats, pigs, turkeys, chickens). Minor species treatment is for all other species. Gamebirds are considered minor species. This declaration allows the veterinarian to use poultry dosages in gamebirds. It still cannot change the feed labels, but it can allow the use of nonlabeled gamebird antibiotics. Despite the special allowances, there are certain drugs that are prohibited under any circumstances for use in food animals. They include the following: chloramphenicol, clenbuterol, diethylstilbestrol, dimetridazole, ipronidazole, nitroimidazoles, furazolidone, nitrofurazone, fluoroquinolones, and glycopeptides. The two drugs most abused are fluoroquinolone and dimetridazole; the use of enrofloxacins or metronidazoles is not permitted. Withdrawal establishment and supervision is the responsibility of the veterinarian. CPG 615.115 directs FDA inspectors to make medicated gamebird feed a low enforcement priority. It does not make medicated feed legal, just low priority. A declaration of this statement can be added to the VFD or Rx. See the VFD form. Vaccination is the practice of exposure of a flock to a pathogen to produce antibodies which will protect the vaccinated flock from the effects of the pathogen in the future. Since the vaccines are not designed for gamebirds, there is some risk in the response. Until the bird’s reaction is known, vaccinate with great care and use the mildest vaccine available. A small trial is not a bad idea to protect against creating a greater problem. As with most atypical species, there are usually very few or no vaccines marketed for the gamebird industry. This creates the situation where commercially produced poultry vaccines created for other species (chickens and turkeys) are used for vaccination of gamebirds. Considerations for selecting poultry vaccines for use in gamebirds would include a nearly identical strain of the infective organism; ease of application; type of application; killed vaccine; safety of a modified‐live vaccine (mlv); and availability of vaccine. Vaccines that have been considered or used in gamebird production include those for quail pox, fowl pox, pigeon pox, cholera (P. multocida), hemorrhagic enteritis (HE)/marble spleen disease (MSD), erysipelas (Erysipelothrix rhusiopathiae), and infectious coryza (Avibacterium paragallinarium). Rarer vaccines include those for Newcastle disease (NDV or APMV‐1), Ornithobacterium rhinotracheale (ORT), and avian encephalomyelitis (AE). Coccidia vaccines are one of the latest considerations. At the time of writing, there are no longer vaccines labeled for gamebirds. The last available product was for quail pox in bobwhite quail. Unfortunately, quail pox vaccination is ineffective against fowl pox of pheasants or partridges. The reverse also holds true: fowl pox vaccination is ineffective against quail pox in bobwhite quail. Currently, the license and rights to quail pox vaccine are pending investment for production. Cholera vaccine (P. multocida) is variable in effectiveness, based on serotype isolated. Commercial poultry vaccines are typically composed as a combination of serotypes 1, 3, and 4. Gamebird isolates range from serotypes 1 to 17 and often are nontypable. The less the similarity, the less the cross‐protection. Use of the least reactive strains or a vaccination method like wing web inoculation should be considered to reduce exposure. Make sure the birds are examined for vaccine “take” to ensure vaccine exposure was completed. Hemorrhagic enteritis of turkeys is the same virus as MSD of pheasants. Be aware that vaccination may still create an unacceptable reaction. Confer with a veterinarian, vaccine producer or technical service personnel to evaluate the threat in your situation. In minimal cleanout programs of the brooder area, preexposure from the previous flock might result in a reaction from a vaccine exposure. Erysipelas and infectious coryza (IC) are bacterial diseases that are commonly observed in gamebirds. These vaccines would only be used if the threat of disease was imminent or nearby commercial flocks were undergoing a serious epizootic. O. rhinotracheale has the potential to reoccur and create havoc just as gamebirds begin to reach release age. Coccidiosis vaccine usually depends on a shortened precocious period or consumption of low numbers of sporulated oocysts. The biggest dilemma lies in the species‐specific nature of coccidia. Pheasant coccidia will not infect quail, chukar, or partridges, etc. The reverse is true. Since the strains differ, infection will not occur and immunity will not follow. Some gamebirds, such as chukar partridges, are more sensitive to infection. While pheasants can develop immunity on a wire floor or ground, chukars will develop a serious infection if raised on the floor without a coccidiostat. If vaccination is needed and an appropriate product is not available, a couple of alternatives might be considered. One is an autogenous vaccine. This includes the use of isolates from the farm to create a vaccine made specifically for the problem strain. Drawbacks include safety issues that may arise from autogenous vaccine use, strains may need to be collected yearly, and the volume of vaccine needed (minimum volume purchase) may be excessive for the farm size. As another option, under the specific requirements of 9CFR.107.1 (Veterinary Practitioners and Animal Owners) and 9CFR.107.2 (Products under State License), an owner may be allowed to create a product needed for immunization. Interested individuals should contact their State Department of Agriculture for more information and to determine whether the owner is qualified. Proper vaccine administration is the key to effectively immunizing a flock. Failure to follow directions will result in insufficient protection or even a disease outbreak. Among the vaccines available, there are five common vaccination methods: water, spray, eye drop, wing web, and injection [4].
9
Field Investigation, Medication, Vaccination, and Diagnostics for Gamebirds
9.1 Field Investigation
9.1.1 Case History
9.1.2 Management and Environmental Evaluation
Item
Notes
□
Clinical signs
□
Morbidity and mortality
□
Contiguous flocks or cohabitation with other avian species
□
Feeders and feed: condition and types
□
Lighting
□
Litter and bedding condition
□
Ventilation
□
Types of waterers and water quality
□
Sanitation: cleaning and disinfecting protocol
□
Biosecurity practices
9.1.3 Diseases and Clinical Signs
9.1.4 Equipment for Farm Visit
9.1.5 Postmortem Examination
9.2 Medication Administration
Active ingredients
Route
Withdrawal time (days)
Dose
SPP
Bacitracin‐MD
Feed
0
200 g/ton
Quail
Amprolium
Feed
0
159 g/ton
Pheasant
Lasalocid
Feed
0
113 g/ton
Chukar
Monensin
Feed
0
73 g/ton
Quail
Salinomycin
Feed
0
50 g/ton
Quail
SDM/Ormetoprim
Feed
0
113.5–68.1 g/ton
Chukar
9.2.1 Extra‐label Drug Use (ELDU)
9.2.2 Animal Medicinal Drug Use Clarification Act (AMDUCA)
9.2.3 Veterinary Feed Directive
9.2.4 Minor Use/Minor Species (MUMS)
9.2.5 Compliance Policy Guide (CPG) for Extra‐label Use of Medicated Feeds for Minor Species
9.3 Vaccines and Vaccine Administration
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