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41.
The effects of heat stress are most pronounced in the lactating dairy cow. The effects manifest themselves in several physiologic mechanisms and include negative effects on the duration of estrus, embryonic development, uterine blood flow, hormonal relationships, fetal growth, and subsequent milk yield. 相似文献
42.
Fifty-two 15-month-old Holstein heifers were synchronised with single or double injections of prostaglandin F(2alpha), followed by an injection of gonadotrophin-releasing hormone (gnrh) 48 hours later, and inseminated 12 to 14 hours after the injection of gnrh (day 0). Half of them were then injected twice intramuscularly with 1.1 mg/kg flunixin meglumine 12 hours apart, on the evening of day 15 and the morning of day 16, and the other 26 were not treated. Pregnancy was diagnosed by ultrasound 29 and 65 days after they were inseminated. On day 29, 20 of the treated heifers were pregnant compared with 13 of the control heifers (P<0.05); on day 65, 18 of the treated heifers were still pregnant compared with 12 of the control heifers (P<0.10). 相似文献
43.
44.
L.A. Starkey A.W. Barrett M.J. Beall R. Chandrashekar B. Thatcher P. Tyrrell S.E. Little 《Journal of veterinary internal medicine / American College of Veterinary Internal Medicine》2015,29(2):552-555
Background
Ehrlichia ewingii, which causes disease in dogs and people, is the most common Ehrlichia spp. infecting dogs in the United States, but little is known about how long E. ewingii infection persists in dogs.Hypothesis/Objectives
To evaluate the persistence of natural infection with E. ewingii in dogs.Animals
Four Class A Beagles; no previous exposure to ticks or tick‐borne infectious agents.Methods
Dogs were exposed to ticks by weekly walks through tick habitat in north central Oklahoma; dogs positive for infection with Ehrlichia spp. by sequence‐confirmed PCR and peptide‐specific serology were evaluated for 733 days (D). Whole blood was collected once weekly for PCR, and serum was collected once monthly for detection of antibodies to Ehrlichia canis (peptide p16), Ehrlichia chaffeensis (indirect fluorescence antibody [IFA] and variable‐length PCR target [VLPT]), and E. ewingii (peptide p28).Results
All dogs (4/4) became infected with Ehrlichia spp. as evidenced by seroconversion on IFA to E. chaffeensis (4/4); PCR detection of E. ewingii (4/4) and E. chaffeensis (2/4) DNA using both nested and real‐time assays; and presence of specific antibodies to E. ewingii (4/4) and E. chaffeensis (2/4). Infection with E. chaffeensis was not detected after D55. Intermittent E. ewingii rickettsemia persisted in 3 of 4 dogs for as long as 733 days.Conclusions and Clinical Importance
Our data demonstrate that dogs infected with E. ewingii from tick feeding are capable of maintaining infection with this pathogen long‐term, and may serve as a reservoir host for the maintenance of E. ewingii in nature. 相似文献45.
NCG Pieri AF Souza JB Casals KCS Roballo CE Ambrósio DS Martins 《Reproduction in domestic animals》2015,50(4):625-631
The precise determination of the embryonic chronology is very important in reproductive biotechnologies, especially in estimating embryonic age. Thus, there is a need for greater knowledge and standardization for determining the chronology of embryonic development and functional morphology. We describe aspects of embryonic development in two domestic carnivores to add knowledge about organ peculiarities and for application in veterinary practice, in prenatal development and in the biotechnology fields. We found that the development of differential characteristics of embryonic organs occurs in the first trimester of pregnancy for both species. Thus, using the combination of the crown‐rump length, macroscopic analysis and optical microscopy, it is possible to predict gestational age more precisely in animals that lack a defined breed and establish an embryonic pattern. 相似文献
46.
47.
Thatcher W Foulger GR Julian BR Svarc J Quilty E Bawden GW 《Science (New York, N.Y.)》1999,283(5408):1714-1718
The distribution of deformation within the Basin and Range province was determined from 1992, 1996, and 1998 surveys of a dense, 800-kilometer-aperture, Global Positioning System network. Internal deformation generally follows the pattern of Holocene fault distribution and is concentrated near the western extremity of the province, with lesser amounts focused near the eastern boundary. Little net deformation occurs across the central 500 kilometers of the network in western Utah and eastern Nevada. Concentration of deformation adjacent to the rigid Sierra Nevada block indicates that external plate-driving forces play an important role in driving deformation, modulating the extensional stress field generated by internal buoyancy forces that are due to lateral density gradients and topography near the province boundaries. 相似文献
48.
Estimating the mass of asteroid 253 mathilde from tracking data during the NEAR flyby 总被引:1,自引:0,他引:1
DK Yeomans J Barriot DW Dunham RW Farquhar JD Giorgini CE Helfrich AS Konopliv JV McAdams JK Miller WM Owen DJ Scheeres SP Synnott BG Williams 《Science (New York, N.Y.)》1997,278(5346):2106-2109
The terminal navigation of the Near Earth Asteroid Rendezvous (NEAR) spacecraft during its close flyby of asteroid 253 Mathilde involved coordinated efforts to determine the heliocentric orbits of the spacecraft and Mathilde and then to determine the relative trajectory of the spacecraft with respect to Mathilde. The gravitational perturbation of Mathilde on the passing spacecraft was apparent in the spacecraft tracking data. As a result of the accurate targeting achieved, these data could be used to determine Mathilde's mass as 1.033 (+/- 0.044) x 10(20) grams. Coupled with a volume estimate provided by the NEAR imaging team, this mass suggests a low bulk density for Mathilde of 1.3 grams per cubic centimeter. 相似文献
49.
R.S. Pleasant J.K. Suagee C.D. Thatcher F. Elvinger R.J. Geor 《Journal of veterinary internal medicine / American College of Veterinary Internal Medicine》2013,27(3):576-582