Objective: To develop a better system for classification of herd infection status for paratuberculosis (Johne's disease [JD]) in US cattle herds on the basis of the risk of potential transmission of Mycobacterium avium subsp paratubeculosis. Sample: Simulated data for herd size and within-herd prevalence; sensitivity and specificity for test methods obtained from consensus-based estimates. Procedures: Interrelationships among variables influencing interpretation and classification of herd infection status for JD were evaluated by use of simulated data for various herd sizes, true within-herd prevalences, and sampling and testing methods. The probability of finding ≥ 1 infected animal in herds was estimated for various testing methods and sample sizes by use of hypergeometric random sampling. Results: 2 main components were required for the new herd JD classification system: the probability of detection of infection determined on the basis of test results from a sample of animals and the maximum detected number of animals with positive test results. Tables were constructed of the estimated probability of detection of infection, and the maximum number of cattle with positive test results or fecal pools with positive culture results with 95% confidence for classification of herd JD infection status were plotted. Herd risk for JD was categorized on the basis of 95% confidence that the true within-herd prevalence was ≤ 15%, ≤ 10%, ≤ 5%, or ≤ 2%. Conclusions and Clinical Relevance: Analysis of the findings indicated that a scientifically rigorous and transparent herd classification system for JD in cattle is feasible.

Parasitic helminth infections in small ruminants are prevalent in South East Asia (SEA), limiting productivity and causing major economic loss for farmers. The hot, wet, tropical climate all year
round favours trichostrongylid infections, predominantly haemonchosis in sheep and goats. Commercial large scale farms, with
more than 300 animals, as well as small holders or backyard farmers with less than 50 animals face the debilitating effects of haemonchosis when they graze their animals as effective worm control is often hampered by anthelmintic resistance. In Malaysia, frequent and indiscriminate use of anthelmintics in the past has resulted
in the majority of the small ruminant population facing resistance to one or more anthelmintics. Several alternative methods of worm control are being employed by farmers; the most important and effective being cut and carry or zero grazing, where the animals are kept in pens and grass is cut and fed. In Cambodia and Myanmar,
ruminants are still tethered or stall fed with minimal drug use. In Indonesia and Thailand, commercial goat and sheep farms are fast expanding to produce breeder stock for the SEA market. However, up to
75% of the small ruminant population is still traditionally managed by small scale farmers. In most of SEA, the McMaster method for faecal worm egg counts is the only diagnostic test used to assess helminthosis in ruminants. There is an urgent need to increase awareness and information on the need for testing faecal samples regularly before drenching, conducting faecal egg count reduction tests on a yearly basis, use of the FAMACHA technique to enable
selective treatment of individual animals. The use of alternative worm control methods to manage helminthosis will help promote effective ruminant production with reduced drug use and ncourage “green” farming methods. Extension of research on local bioactive plants which may have the potential to control helminthosis may also be beneficial in the longer term.