Disease screening, treatment, and surveillance are critically important components of herd health programs. These practices require regular observation of the herd, whole herd surveillance testing for certain diseases, and timely necropsies for animals who have died or been euthanized.
A key to management of disease is fast and accurate diagnosis, followed by effective treatment. This requires a good surveillance system—the ability to identify, examine, and treat sick animals. Early identification of sick animals is critical to treatment success, and therefore it is essential that personnel be trained and proficient in distinguishing between sick and healthy cattle.
Characteristics of sick cattle include:
lack of appetite
lameness or abnormal gait
nasal and ocular discharge
increased breathing rate
rough hair coat
loose or very firm feces
abnormal abdominal fill
spending an abnormal amount of time at the water source or segregated from pen mates
Cattle with these or other clinical signs of illness, or that just look "off," should be examined more closely and, if necessary, treated.
The herd health management plan should include the steps to take after an animal is treated and also specific plans for reevaluation and relocation. Animals identified as chronically ill with little to no chance of recovery should be marketed for salvage value (only if there is no violative residue) or should be euthanized to minimize pain and discomfort.
Pens, pastures, or groups of animals from which individual sick animals are identified should be closely observed to quickly identify other sick animals, as well as to avoid an epidemic or disease outbreak. Despite its importance, group surveillance remains a challenge, and it is often difficult to distinguish sick from recently received animals, particularly for calves that were recently weaned. In addition to visual observation, operations should also consider technologies such as monitoring and/or evaluation systems that use objective measurements to identify sick animals.
The herd veterinarian should specify procedures for the treatment of sick and injured cattle by providing one or more standard protocols that outline the treatments for individual diseases, injuries, or conditions. Relevant information includes (but is not limited to) drug dosages, treatment intervals, routes of administration, and withdrawal times.
Similarly, protocols should be developed for the prevention and control of disease. Protocols should be followed strictly by all personnel so that the success or failure of treatment can be evaluated accurately and the risk of human food safety hazards is minimized.
The effectiveness of the treatment protocol should be evaluated regularly by determination of the response rates for the various treatment regimens. Failure to develop and implement appropriate treatment protocols often leads to the use of many different drugs indiscriminately, which then leads to excessive treatment costs, diminished treatment success, and increased risk of development of drug resistance.
Records are essential to monitor the incidence of disease, response to treatment, and impact of disease on performance. To be used as effectively as possible, records should be analyzed on a regular basis, and recordkeeping templates should be designed to enhance ease of data collection, analysis, and interpretation.
If not previously identified, each animal that is evaluated or treated for disease should be identified and the relevant information recorded. Relevant information may include:
pen or pasture
animal measurements, such as body temperature or weight
location of the animal before and after treatment
necessary withdrawal time
safe to ship date
The severity of the illness should also be assessed and recorded to adequately evaluate response to treatment. This information can be used to generate a report for each animal that was treated and decide whether an animal should be culled or to determine treatment efficacy.
For operations in which morbidities and mortalities occur on a regular basis, reviews of daily morbidity and mortality records can yield insights. When aggregated over time, these records can be particularly useful in evaluating and revising protocols and management practices as well as training personnel. At minimum, cause of death, as determined by necropsy, should be summarized and evaluated frequently. Necropsy examinations are likely best performed by the herd's veterinarian on operations in which mortalities are rare. For operations that regularly experience mortalities, continued training of on-site personnel to conduct necropsies can be incredibly valuable. In addition, technologic advancements of cell phone cameras have simplified the process of remote necropsies.