Sheep Industry News February 2024

Animal Health Continued from Page 19

from infection by being born and raised in a clean environment. Producers should also be aware that a recent change in the blood test for OJD in sheep appears to generate false positives, so Busch recommends that producers work with their vets to resa mple and follow up with fecal PCR tests. RESPIRATORY DISEASE Dr. Lindsay Piel of the Agriculture Research Service and Dr. Maggie Highland of the Wisconsin Veterinary Laboratory provid ed updates on Mycoplasma ovipneumonia research in their labs. Piel explained that this pneumonia-causing respiratory patho gen is present in a large percentage of domestic sheep flocks, and is part of a polymicrobial disease, meaning it’s caused by more than one infectious agent. Piel’s continuing Mycoplasma research has found that big horn sheep and domestic sheep have different baseline immune systems, and detection of M. Ovipneumoniae varies depending on the strain involved. Researchers have isolated strains from sheep at the U.S. Sheep Experiment Station, and the samples will undergo whole genome sequencing to help characterize the dif ferent strains. Piel’s efforts will examine how these strains change through time. Highland explained that while M. Ovi was traditionally believed to only be associated with sheep and goats, she became interested in the possibility of it occurring in other species nearly 10 years ago. Intrigued with the idea, she was able to detect the pathogen in a white-tailed deer, and eventually in a moose and other species. But what Highland had actually detected is a novel strain of the pathogen (that has yet to be named). Improved testing protocols since the discovery has led to further detections, and Highland cautions that published testing protocols prior to 2016 caused nu merous false positives for M. Ovi when it was actually this novel pathogen. Unfortunately, the recognition of this novel strain and inter est in its impacts on M. Ovi diagnostics hasn’t received much attention from researchers, even though federal land management agencies insist on separating domestic sheep from wild sheep based on fears of pathogen transmission.

country’s cattle population since 1908, there is mounting concern of interspecies transmission risk, as well as the economic impact to American sheep production. OJD is caused by a bacterium that infects ruminants usually through shedding of the bacterium in feces. OJD is a chronic, en teric wasting disease, with clinical signs developing within six to 12 months of infection, and causing death by the time the animals are 3 to 5 years of age. OJD is contagious, which means that it can spread from one animal to another before the producer knows that the disease is present. Busch said OJD is estimated to be present on 4.7 percent of sheep operations in the United States, causing an estimated 4-per cent increase in mortality in affected flocks. Since there is no cure for the disease, Busch said that producers are faced with compli cated tradeoffs. Test and culling programs have limited applica tion due to the cost of testing compared to the value of individual animals. Busch recommends that producers check their ewes body con dition scores at mating, and cull ewes before the high-risk shed ding that occurs at lambing. Producers should also manage their stocking rates in lambing paddocks so that lambs are protected

Dr. Cindy Wolf Animal Health Committee Co-Chair

Resource Management Continued from Page 28

February 2024 • Sheep Industry News • 29 carbon in the Southeast; and hiring staff to provide more education and support to the growing coalition. GRAZING Debbie Webster of the National Graz ing Lands Coalition laid out NGLC’s plans for 2024: a new project to create a technical service provider in Florida; continuing to work on climate smart community hubs and marks in the West; promoting, measuring and studying

this is a circus,” she said of working with the current Congress. But in addition to working with mem bers of Congress on appropriations and policy that serve sheep producers, PLC is working in the agency regulatory realm, as well. Much of the regulatory changes pro posed by the Biden Administration in 2023 will be “coming home to roost in 2024."

including a new Farm Bill package, providing funding for the U.S. Sheep Experiment Station and WS, as well as riders prohibiting listing sage grouse as a federally protected species, and requir ing federal agencies to update the science being used in risk of contact models between domestic and wild sheep. “In the current atmosphere of gridlock,