FIELD OF THE INVENTION 
     The present invention relates to a system and method for vaccinating animals. Specifically, the current invention comprises an automated system and method for vaccinating poultry. 
     BACKGROUND OF THE INVENTION 
     Modern integrated poultry operations are expansive, with the total industry producing an estimated 9.1 billion broilers in 2007. In modern broiler production operations, up to 25,000 birds are housed in one facility and vaccinating this large number of birds is a time consuming and labor intensive process. Currently vaccines are commonly administered through a manual blower-spray process or the vaccines are mixed into drinking water and then made available to the poultry. 
     In accordance with the manual blower-spray vaccination process, a liquid form of the vaccine is directed into a conventional “leaf blower”-type portable mechanism so that the vaccine is entrained in the blower discharge air. As an operator moves about in a poultry pen, the operator directs the blower (with entrained vaccine) towards the poultry and attempts to ensure that all of the birds are exposed to the vaccine. 
     However, the manual blower-spray process results in inconsistent and essentially random application of the sprayed vaccine. Further, the process is time consuming and unpleasant for the spray operator and the poultry. The blower causes dust and feces to be at least temporarily suspended in the air and the noise disturbs and stresses the poultry. 
     In accordance with the drinking water vaccine administration process, water is withheld from the poultry for a short time, and then when the drinking water is restored, the water contains the vaccine. However, many of the vaccines do not readily lend themselves to uniformly dissolving in large quantities water and the dilution of the vaccine means that greater quantities are required to vaccinate a selected number of birds. Further, the nipples in the drinking lines are commonly worn, leaky, and somewhat inefficient so that significant quantities of the solution simply drip onto the pen floor. 
     There are also biological concerns associated with the drinking water vaccine administration process. Orally applied vaccines are absorbed through the stomach lining and may become mixed with other stomach contents. Consequently, orally applied vaccines are generally less reliable and require the ingestion of greater quantities of the vaccine to ensure successful vaccination. 
     An improved method and system of vaccinating poultry would facilitate faster vaccination, reduce labor costs, improve bird health through uniform application, and reduce production losses. The current invention comprises an automated spray-type vaccine system that allows the vaccine to be absorbed but does not significantly disturb the birds or require an operator to physically enter the poultry pen during the vaccination process. 
     SUMMARY OF THE INVENTION 
     The current invention is directed to a poultry vaccination system. The vaccination system comprises a vaccine spray means positioned adjacent to a sustenance supply means. In the preferred embodiment, the sustenance comprises water. In operation, the supply of water is temporarily withheld and then restored. As the poultry gather around the water line, the vaccine spray means sprays the area so that the poultry inhale vaccine spray solution and are successfully vaccinated. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic of the current invention. 
         FIG. 2  is a table showing the results of non-linear regression analyses to determine 90% time constants (2τ). 
         FIG. 3  shows normalized water consumption data after a water supply interruption associated with the invention testing process. 
         FIG. 4  shows the average geometric mean titers (GMT) for vaccinated and control birds for each experimental trial discussed infra. 
     
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
     The present invention comprises an automated vaccination system  10  generally shown in  FIG. 1 . 
     In the preferred embodiment, the system  10  comprises a vaccine mixing means  12  and a pressurizing pump  14 . The specific form of the vaccine mixing means  12  is contingent on the type of vaccine used and the recommendations of the vaccine manufacturer. Based on the inventor&#39;s experimental results, a large reservoir for pre-mixing of the vaccine solution may be impractical given the volume of water required to treat the entire flock. An in-line mixing system which meters a vaccine into a flowing carrier fluid (such as water) may be may be the most practical. In its most basic form, the vaccine mixing means  12  may simply be a drip bottle or a similar mechanism for metering a prepared liquid vaccine into a vaccinating spray solution. 
     In the preferred embodiment, the pressurizing pump  14  pumps the vaccinating solution into a distribution portion of the system  10 . In alternative embodiments the pump  14  may be unnecessary because the vaccinating solution may be pressurized by other means, such as gravity (i.e. hydrostatic pressure), systemic utility water pressure, or the like. 
     The pump  14  is connected to a tubular spray bar  16  which transports the vaccinating solution into the poultry pen for distribution. The dimensions of the spray bar  16  are based on the needs of an operator or the nature of a particular vaccine. A plurality of nozzles  18  are positioned along the length of the spray bar  16  and project outwardly from the spray bar  16 . (Note that for the sake of simplicity, only one of the nozzles  18  are labeled in  FIG. 1 .) In the preferred embodiment, the nozzles  18  are approximately three feet apart and create a fine misting spray that settles downwardly toward the floor of the poultry pen. In alternative embodiments, the spray bar  16  may simply have a series of apertures formed so that when the spray bar  16  is pressurized, the vaccine solution to sprays directly from the spray bar  16 . 
     In the preferred embodiment, the spray bar  16  is suspended from above a conventional nipple-type poultry drinking line  24  by a pair of supporting cables  20  attached to a means  22  for raising and lower the spray bar  16 . In the preferred embodiment, the means for raising and lowering the spray bar comprises an electric or mechanical winching system  22  and the spray bar  16  is lowered to approximately thirty inches above the drinking line  24  during the vaccination process. 
     In alternative embodiments, the spray bar  16  may be supported from the side or from below and the position of the spray bar  16  may be modified by any means known in the art. The position of the spray bar  16  relative to the drinking line  24  may also be modified. Further, the entire process may be automated so that a programmable controller  13  initiates multiple vaccination cycles of the same or different vaccines. 
     In operation, during a vaccination process, the spray bar  16  is lowered to a position adjacent a conventional poultry drinking line  24 . The poultry are then deprived of water for a short time to increase the motivation of the poultry to congregate around the drinking line  24 . When the flow of water is then restored, the vaccination solution is supplied to the spray bar  16  so that the spray bar nozzles  18  produce a vaccine solution mist. As the mist settles over the poultry, the poultry inhale the vaccinating solution mist, thereby vaccinates the poultry. 
     Vaccination System Testing Process 
     The initial phase of the vaccination system testing process was designated as Phase I. Phase I research set out to determine if a stationary vaccine application system was feasible in pilot-scale studies. Objectives for Phase I were: (1) determine required vaccination delivery time and (2) determine seroconversion rates of broiler chickens vaccinated for Newcastle disease (viral disease) with the automated spray system of the current invention. Objective 1 addressed baseline data requirements for the vaccine application system specifications and Objective 2 evaluated the use of the automated system in comparison to non-vaccinated control birds. 
     The pilot-scale prototype was constructed such that it can be transported for use in different research facilities with a minimum of disassembly. All control hardware and system elements (such as valves and pumps) were mounted to a cart and plumbed to the spray lines with flexible hose. 
     Vaccination Application Time Experiments 
     In order to properly design a spray system that would apply viable vaccine to a poultry flock, the duration of spray time was required. A study to determine application time was conducted in July 2007 and a total of three vaccination application trials were conducted, two with layer pullets and one with straight-run broiler chicks. The application time was modeled using a first order system response to a step increase and subsequent exponential decay (Equation 1).
 
 y=y   0   +a·e   t/τ   (Equation 1)
 
where: y=normalized water consumption
 
y 0 =baseline water consumption
 
a=regression constant
 
t=time
 
τ=62% time constant.
 
     The time constant, τ, was determined using non-linear regression analysis; τ represents the initial slope of the decay and corresponds to the time required to reach 62% of the final value and 2τ represents the 90% point. All raw data were normalized to non-dimensionalize the analysis and remove any inconsistencies that may occur from an increase in normal water consumption over the course of the experiment; data were transformed by dividing the measured flow rate by the maximum flow rate observed after water was returned to the birds. 
     Example data for water consumption patterns is shown in  FIG. 2 , along with a plot of the regression equation. The results show that the time to return to within 10% of normal water consumption after elevated water consumption due to prior water withdrawal from chickens before vaccine administration was approximately 18.6 minutes. 
     Intervet™ (manufacturer of the vaccine used in the spray application trials) technical services recommends vaccine be used within one hour of reconstitution. The inventor&#39;s measurements show that the duration of the drinking event is well within the time limits of vaccine effectiveness. 
       FIG. 3  shows normalized water consumption data associated with the inventor&#39;s measurements. Note the exponential decay of the data, which is indicative of a first order system response. Data associated with the regression equation is represented as the dashed line in  FIG. 3 . 
     Vaccination Application Experiments 
     Three vaccine application trials were conducted with both layer pullets and broilers. Consultation with poultry veterinarians indicated that Infectious Bronchitis would be better suited for initial experiments of this type, rather than Newcastle disease. The objectives of Phase I research were to determine if vaccine could successfully be applied by such a system, hence the change of vaccine was immaterial. For the vaccination trials, blood samples were collected from 30 birds in each of four treatment groups (2 vaccination groups, 2 control groups), and titers were obtained by ELISA methods. Geometric mean titers were statistically analyzed using an ANOVA to determine if differences existed between the treatment groups for all three trials. Statistical significance was considered at P≦0.05. 
     Bronchitis vaccine was applied to one group of commercial layer pullets on Sep. 4, 2007, and blood samples were collected 21 days later on Sep. 25, 2007. Serology results verified exposure of the birds to the vaccine which was increased when compared to control birds, but titers were lower than typically observed in the field in commercial broiler chickens. A second application was performed on Oct. 11, 2007, and blood samples were collected on Nov. 5, 2007. Results from the second application again showed increased titers when compared to the control birds. Noise was noted as one aspect which required further attention to minimize. 
     The final live bird experiment was repeated with broiler chickens in November 2007. At 19 days of age, 500 broiler chickens were evenly distributed in the test pens. Vaccine was applied November 2 at 22 days of age after a two-hour withdrawal from drinking water. The birds did not approach the water line and stay under the spray as expected, most likely due to insufficient withdrawal time. One pen of birds was herded toward the water line to increase contact with the vaccine spray. Given the cool weather experienced during this test, it is likely that withdrawal time should be modified with weather conditions. However, for the group of birds encouraged to move underneath the vaccine spray, titers were increased when compared to the other group of exposed birds and control birds. 
       FIG. 4  shows the average geometric mean titers (GMT) for vaccinated and control birds for each trial. In all trials the largest geometric mean titers were observed in birds vaccinated with the spray system and were significantly different (P≦0.02). In all cases the GMT for vaccinated birds was increased over the control birds. In trials 1 and 3 there was variation within the spray vaccinated pens of birds. Two problems were identified which are probable causes of this variation, the first being noise; the pullet chicks are flighty by nature and the unfamiliar noise caused birds to crowd near the center of the pen. However, even with this variation the overall geometric mean titer was greater than that observed in control birds. The previous noted problem in the broiler chick trial (#3) regarding the lack of motivation to drink after two hours of water restriction was likely due to seasonal differences as this trial was conducted during late fall; however, when compared to the control group, geometric mean titers remained increased for the treatment group. 
     Trials conducted under Phase I research have shown that vaccine can be successfully spray applied from an automated, in-house system, and identified issues with the design which require refinement for commercial application. The optimum water withdrawal period under cool season conditions may be different than that originally determined during warm weather, and warrants further investigation, which is proposed for Phase II work to provide prescriptive recommendations for the operation of this system in the field. Noise can be reduced using a nozzle of different design which provides similar spray characteristics and alternative nozzle types will be investigated. 
     CONCLUSION 
     Phase I research resulted in positive proof-of-concept for the objectives set out in the Phase I proposal. Vaccines can be successfully applied with this method, but as with all experimental development projects, improvements in design and performance are necessary and further research and development are warranted. Our Phase I research identified critical design and application issues, resulting in more complete design and performance criteria. For example, a large reservoir for pre-mixing of the vaccine solution is impractical given the volume of water required to treat the entire flock for post drinking water withdrawal drinking event, thus in-line mixing equipment will be required. 
     For the foregoing reasons, it is clear that the invention provides an innovative system for vaccinating poultry. The invention may be modified in multiple ways and applied in various technological applications. For example, (although not an obvious modification of the current invention) the system may be used for swine, cattle, etc., or any other animal raised in groups and for which an airborne application of a vaccine or other inoculation is effective. 
     The current invention may be modified and customized as required by a specific operation or application, and the individual components may be modified and defined, as required, to achieve the desired result. For example, although the current invention uses the deprivation of drinking water as a motivation to entice the poultry to approach the vaccine spray line, other types of motivators or sustenance could also be used as a motivator. Examples include a water or non-water-based hydration means that is enhanced with salt or a sweetner, or the like. Although not an obvious modification of the current invention, different types of nourishment and foodstuffs should also be included as motivators that are within the scope of the current invention. 
     Although the materials of construction are not described, they may include a variety of compositions consistent with the function of the invention. Such variations are not to be regarded as a departure from the spirit and scope of the invention, and all such modifications as would be obvious to one skilled in the art are intended to be included within the scope of the following claims.
The automated vaccination system enables an operator to effectively vaccinate large numbers of poultry by motivating the poultry to congregate, and then spraying a vaccination solution in the area of the congregated poultry. In the preferred embodiment, drinking water is withheld from the poultry. The drinking water is then restored so that the poultry congregate around the drinking line. As the poultry gather around the drinking line, a spray bar sprays vaccination solution around the poultry so that the poultry inhale the vaccination solution and are successfully vaccinated.