By Brad White, DVM, MD
Kansas State University,
College of Veterinary Medicine
Stocker calves are managed as groups, yet individual identification provides more information to the farm decision maker.
Individual animal information can be used to divide health and performance figures into relevant sub-groups for further analysis.
Animal health records are a significant component of the decision process regarding diagnosis and treatment plan formulation, and individual animal identification facilitates evidence based decisions.
Individual Identification in the Stocker Systems
Animals entering the stocker unit are often identified by group or sale lot. Individuals may be designated by farm tags, or have new unique numbers placed at arrival. Cattle are managed as groups, but individual identification offers management benefits to the operational decision makers. Electronic identification facilitates record keeping on individual animals and offers advantages related to data entry and management.
Performance and health statistics are important to the profitability of the stocker operation. The utility of individual animal identification is not to use the information solely for decisions about that calf, but rather to divide the data into relevant sub-groupings for analysis. Classification of individual animal data into groups should be based on areas where management decisions impact outcomes. An example includes response rates to a specific therapy in a distinct class of cattle. Performance based on animal type or source may also be used to generate specific breakeven purchase values calculated by historical data.
Evidence-Based Animal Health Decisions
Any good health program is in constant evolution and improvement based on the cycle of implementation, evaluation, change and repeat. Evaluation is based on good records including diagnosis evaluations, treatment response rates, disease rates, and necropsy findings. Our ability to maintain good health statistics on the animals starts at initial processing or on arrival.
Each group of calves entering the facility should be recorded along with initial procedures performed to these animals. Accurate processing records are important to enable us to maintain quality controls and evaluate product performance. This is also important because the administration of many products induces a withdrawal time on each set of calves and proper records makes compliance with withdrawal times possible.
Recording the number of head, where they came from and which pen they were placed in is critical for determining disease and mortality incidence rates. These numbers can be maintained with minimal time and effort.
Bovine Respiratory Disease (BRD) is the primary cause of morbidity and mortality in the preconditioning yard. Cattle illness creates expenses related to death loss, treatment cost, and reduced performance (gain, feed efficiency). Evaluation of number of animals pulled from the pen is an important tool for continual improvement of diagnosis techniques. Rectal temperature can provide a quick, general guide for assessment of pulling patterns. A good rule of thumb is 5-10% of the pulls with a rectal temperature of 104º F or less. If more than 10% has a lower temperature, there may have been too many animals pulled or the diagnosis may not be infectious respiratory disease. If all the pulls have a rectal temperature of 105º F or higher then it is likely that there are more animals in the pen that need to be segregated and treated. If only a handful of the animals pulled for treatment have a fever, we may have misdiagnosed illness in some of the animals and pulled too many.
Pen morbidity and mortality rates are good gauges for level of illness within the group of calves. These rates can be benchmarked against other groups of similar type animals on the farm and through the industry to evaluate health performance. Individual animal treatment records are important not only for evaluating animal response, but also for ensuring adherence to drug withdrawal guidelines. All individual treatments should be recorded on a daily basis including the date, animal treated and the drugs administered. It may also be helpful to institute a simple visual measure such as notching an ear tag or placement of a special treatment identification to determine how many times an animal has been treated.
The first treatment response rate is an important number when evaluating efficacy of the initial treatment regime. This number is calculated by dividing the number of animals retreated by the number of first pulls. This reveals the retreatment rate; conversely first treatment response rate is one minus the retreatment rate. Ideally, the first treatment response rate should be greater than 80%. The rate may be below the target due to: ineffective treatment selection, misdiagnosis of the disease condition, or delayed intervention (failed to notice until too late).
The treatment interval is the distance between the first and second treatment (although it may be calculated using any two successive treatments). The average treatment interval is influenced by the drug selected at the first treatment and the presence or absence of a post-treatment moratorium. Excessively long treatment intervals on a pen basis may indicate disease clearance and reinfection. Long treatment intervals on individuals may indicate a calf which never fully recovered from the initial insult and was not retreated until disease had progressed.
The Case Fatality Rate (CFR) is also a good method to evaluate both disease identification and treatment regime. CFR is calculated by dividing the mortality number by the number of animals treated. Ideally, the CFR is in the 6-8% range depending on the type and risk level of the animals. A higher CFR could indicate poor treatment selection, misdiagnosis of disease, or delayed identification of sick animals. A low CFR could mean that too many calves were pulled and treated and the health program is economically inefficient.
Stocker operations differ significantly in management techniques and health programs. The utility of individual animal identification is to improve the decision process related to evaluation of health and performance records. Electronic identification minimizes the labor required for data entry and management, but is not necessary for an operation to maintain individual calf records.