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This field study investigated whether the administration of a single dose of gonadotropin‐releasing hormone (GnRH) to dairy cows without a corpus luteum (CL) 4 weeks after calving can improve reproductive performance. Holstein dairy cows underwent ultrasonography to assess the presence of ovarian structures at 29.2 ± 5.2 days post‐partum, and cows were divided into two main groups based on the presence (CL group, n = 230) or absence (non‐CL group, n = 460) of a CL. The non‐CL group was further randomly divided into two subgroups based on the administration of GnRH (non‐CL GnRH group, n = 230) or no GnRH (non‐CL control group, n = 230). Subsets of cows from non‐CL control (n = 166) and non‐CL GnRH (n = 175) groups received a second ultrasonography at 44.5 ± 5.4 days post‐partum to assess CL formation. The percentage of cows with CL at the second ultrasonography was greater in the non‐CL GnRH group (70.9%) than in the non‐CL control group (53.0%, p = 0.0006). The hazard of the first post‐partum insemination by 150 days in milk (DIM) was higher in the CL group than in the non‐CL control group (hazard ratio [HR]: 1.36, p = 0.001). The probability of a pregnancy to the first insemination was higher in non‐CL GnRH (odds ratio [OR]: 1.50, p = 0.04) and CL groups (OR: 1.55, p = 0.03) compared to the non‐CL control group. Furthermore, the hazard of pregnancy by 210 DIM was higher in non‐CL GnRH (HR: 1.30, p = 0.01) and CL (HR: 1.51, p = 0.0001) groups than in the non‐CL control group. In conclusion, administration of GnRH to dairy cows without a CL 4 weeks after calving was associated with an increase in ovulation and improved reproductive performance. 相似文献
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M Dorsch B Meehan WP Michalski HG Heine AJ Foord G Carlile J Wang S McCullough K Zuelke 《Australian veterinary journal》2016,94(3):64-66
In this study, we explored the potential utility of the human‐focused FilmArray® Respiratory Panel for the diagnosis of a broad range of influenza viruses of veterinary concern as compared with the standard portfolio of recommended TaqMan®‐based diagnostic tests. In addition, we discuss some potential operational advantages associated with the use of such integrated sample extraction, amplification and analysis devices in the context of a future long‐term, dual‐role strategy for the detection of emergency diseases of both human and veterinary concern. 相似文献
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Craighead FC 《Science (New York, N.Y.)》1916,43(1100):133-135
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Diabetes mellitus: induction in mice by encephalomyocarditis virus 总被引:22,自引:0,他引:22
Hyperglycemia and lesions of the pancreatic islets of Langerhans developed in some, but not all, adult mice infected with a variant of the encephalomyocarditis virus. Large amounts of virus were recovered from the pancreas during acute stages of infection. At this time blood glucose concentrations were markedly elevated and the islets of Langerhans exhibited focal necrosis and degranulation of beta cells. Evidence of abnormal glucose metabolism persisted for varying periods after recovery from the infection. The islets of Langerhans of chronically hyperglycemic mice were distorted and decreased in size, and the beta cells were degranulated. Encephalomyocarditis virus appears to cause diabetes mellitus by reducing the mass of functional beta cells of the islets of Langerhans. 相似文献
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Craighead HG 《Science (New York, N.Y.)》2000,290(5496):1532-1536
Nanoelectromechanical systems are evolving, with new scientific studies and technical applications emerging. Mechanical devices are shrinking in thickness and width to reduce mass, increase resonant frequency, and lower the force constants of these systems. Advances in the field include improvements in fabrication processes and new methods for actuating and detecting motion at the nanoscale. Lithographic approaches are capable of creating freestanding objects in silicon and other materials, with thickness and lateral dimensions down to about 20 nanometers. Similar processes can make channels or pores of comparable dimensions, approaching the molecular scale. This allows access to a new experimental regime and suggests new applications in sensing and molecular interactions. 相似文献
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Craighead Kimberly Yacelga Milton Wan Ho Yi Vogt Robert Cushman Samuel A. 《Landscape Ecology》2022,37(1):129-146
Landscape Ecology - Few habitat modeling studies consider multiple spatial or temporal scales; less identify the operative scale of an organism's response to predictor variables. Optimizing... 相似文献