Craig McConnel, Claire Burbick, Yoko M Ambrosini
Read Promoting livestock health and resilience on AVMA.org DOI: 10.7589/jwd-d-25-00078
Abstract: Washington State University’s (WSU’s) Agricultural Animal Health Program and Field Disease Investigation Unit (FDIU) enhance animal well-being and lifetime productivity through field investigations and research into disease and production problems on farms around the Pacific Northwest. This organizational model links private veterinary practitioners, academics, state animal disease diagnostic laboratory services, and federal agricultural animal disease control programs. These cross-disciplinary collaborations provide the knowledge, methods, and perspectives to tackle complex challenges involving livestock health, productivity, and zoonotic disease.
Larell Bermudez-Koch, Melissa Holahan, Hanna E Sihler, Claire Burbick, Laura Williams, Korakrit Poonsuk, Craig S McConnel
Read the full journal on AVMA.org DOI: 10.2460/ajvr.24.11.0329
Abstract
Objective: To understand Mycobacterium avium subspecies paratuberculosis (MAP) diagnostic trends based on small ruminant submissions to the Washington Animal Disease Diagnostic Laboratory.
Methods: Small ruminant MAP serum ELISA and fecal PCR results between May 1, 2015, and June 1, 2024, were obtained from Washington Animal Disease Diagnostic Laboratory. Prevalence estimates were established for goats and sheep relative to overall sample submissions, individual animals tested, and herds. Species-level differences in prevalence were evaluated based on ELISA manufacturer, age, sex, and breed.
Results: A total of 108,092 small ruminant samples were submitted for MAP serum ELISA (n = 98,538 IDEXX Inc; 9,554 VMRD Inc) and 1,090 samples for fecal PCR. For sheep and goats combined, there was an overall 6-fold difference in positive prevalence between the 2 ELISA tests based on submissions (0.9% vs 5.8%), individuals (1.0% vs 5.8%), and herds (3.7% vs 24.2%). In comparison, combined fecal PCR results for sheep and goats indicated positive prevalences of 6.5% for submissions, 6.6% for individuals, and 11.2% for herds.
Conclusions: This study offers valuable insights into the prevalence of MAP infection in domestic sheep and goats across the United States, the preferred diagnostic tests among producers and veterinarians, and variations in ELISA test characteristics.
Clinical relevance: The results highlight the poor alignment between small ruminant MAP diagnostic usage and recommendations to use ELISA tests primarily as a screening tool for control programs in MAP-infected herds with high prevalence (≥ 5% test positive) and fecal PCR or culture-based testing to enhance surveillance, eradication, or confirmation of Johne clinical diagnoses.
A. Martelo Pereira, M.I. Marcondes, C.C. Figueiredo
Read more on ScienceDirect.com DOI: 10.1111/rda.70206
Abstract: This study aimed to evaluate the economic and environmental impacts of clinical cure failure of metritis in dairy herds using a dynamic Markov chain model. Metritis incidence was set at 25% of postpartum cows, with 3 scenarios simulated over a 10-yr horizon: Base (no metritis), Cured (all metritis cases cured), and Not Cured (no cases cured). Herd size was constrained to 900–1,000 milking cows, and all metritis cases were treated with ceftiofur crystalline-free acid. Outputs from year 10 (steady-state herd) were used for comparison. Total herd population was greatest in the Not Cured scenario, driven by a higher proportion of heifers retained for replacement. Although the number of lactating and dry cows remained similar across scenarios (constrained by our model), milk yield declined from 42 kg/d (Base) to 40 kg/d (Cured) and 37 kg/d (Not Cured). Heifer pregnancy rate did not differ among scenarios, whereas cow 22-d pregnancy rate decreased from 25% (Base) to 22% (Cured) and 20% (Not Cured). Cow culling was highest in the Not Cured scenario. Milk revenue and income over feed cost declined with increasing disease severity, whereas operating, reproductive, and replacement costs increased. Overall farm profit decreased from $1.30 million ($1,225/cow) in the Base scenario to $1.16 million ($1,067/cow) in the Cured and $0.92 million ($838/cow) in the Not Cured scenario. Methane, nitrogen, and phosphorus excretion per liter of milk increased progressively from the Base to the Not Cured scenario. The estimated cost per case of metritis increased from $460 in the Cured scenario to $1,403 when cure failed. These results demonstrate that clinical cure failure of metritis substantially reduces herd productivity, profitability, and environmental efficiency, emphasizing the importance of metritis prevention and successful clinical resolution.
Interpretive Summary: This study evaluated the economic and environmental consequences of clinical cure failure of metritis in dairy herds using a Markov chain model. Three scenarios were simulated: Base (no metritis), Cured (all cases cured), and Not Cured (no cases cured). Cure failure reduced milk yield, reproductive performance, and altered herd structure toward greater replacement intensity, and increased operating and reproductive costs. Although animal sales increased, farm profit and income over feed cost declined. Methane, nitrogen, and phosphorus excretion increased with cure failure. These findings highlight that preventing metritis and achieving clinical resolution are paramount for improving herd sustainability.