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The majority of pregnancy loss in ruminants occurs during the first three weeks after conception, particularly during the period of conceptus elongation that occurs prior to pregnancy recognition and implantation. This review integrates established and new information on the biological role of ovarian progesterone(P4), prostaglandins(PGs),interferon tau(IFNT) and cortisol in endometrial function and conceptus elongation. Progesterone is secreted by the ovarian corpus luteum(CL) and is the unequivocal hormone of pregnancy. Prostaglandins(PGs) and cortisol are produced by both the epithelial cells of the endometrium and the trophectoderm of the elongating conceptus. In contrast, IFNT is produced solely by the conceptus trophectoderm and is the maternal recognition of pregnancy signal that inhibits production of luteolytic pulses of PGF2αby the endometrium to maintain the CL and thus production of P4. Available results in sheep support the idea that the individual, interactive, and coordinated actions of P4, PGs, IFNT and cortisol regulate conceptus elongation and implantation by controlling expression of genes in the endometrium and/or trophectoderm. An increased knowledge of conceptus-endometrial interactions during early pregnancy in ruminants is necessary to understand and elucidate the causes of infertility and recurrent early pregnancy loss and provide new strategies to improve fertility and thus reproductive efficiency. 相似文献
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Jitender Bhandal Alan Kuzma Greg Starrak 《The Canadian veterinary journal. La revue veterinaire canadienne》2008,49(10):1002-1004
The abdominal ultrasonogram of a dog admitted for acute onset of collapse revealed an abnormally displaced left medial liver lobe with no blood flow. Surgical and histological findings confirmed the ultrasonographic diagnosis of left liver lobe torsion. Ultrasonographic findings were useful and probably sufficient for a correct diagnosis. 相似文献
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Alicia M. Skelding Alexander Valverde Greg Kilburn 《Veterinary anaesthesia and analgesia》2021,48(3):407-414
ObjectiveTo evaluate anesthetic conditions and postoperative analgesia with the use of intraoperative constant rate infusions (CRIs) of fentanyl–lidocaine or fentanyl–ketamine in dogs undergoing thoracolumbar hemilaminectomy.Study designProspective, randomized, blinded, clinical study.AnimalsA total of 32 client-owned dogs.MethodsDogs were premedicated with fentanyl (5 μg kg–1) administered intravenously (IV), anesthesia was induced with IV alfaxalone and maintained with isoflurane. Fentanyl (0.083 μg kg–1 minute–1) was infused IV with either ketamine (0.5 mg kg–1; then 40 μg kg–1 minute–1; group KF) or lidocaine (2 mg kg–1; then 200 μg kg–1 minute–1; group LF) assigned randomly. Heart rate, noninvasive arterial pressures, respiratory rate, esophageal temperature, end-tidal partial pressure of carbon dioxide and isoflurane concentration were recorded throughout anesthesia. Maintenance of anesthesia, recovery and postoperative pain (Glasgow Composite Pain Scale) were scored. Cardiopulmonary data were analyzed using a two-way anova with repeated measures, demographics of the two groups with a t test, and scores with Mann–Whitney U test, with p < 0.05.ResultsAll dogs recovered from anesthesia without complications. No significant difference was found between groups for cardiopulmonary variables, total anesthesia time, sedation score and requirement for postoperative sedation or for rescue analgesia. Anesthetic maintenance score was of lower quality in KF than in LF [median (interquartile range): 0 (0–0.5) versus 0 (0–0); p = 0.032)], but still considered ideal. Recovery score was higher and indicative of less sedation in LF than in KF [1 (1–1.5) versus 0.5 (0–1); p < 0.0001]. Pain score was higher in KF than in LF [2 (1–3) versus 1 (1–2); p = 0.0009].Conclusions and clinical relevanceBoth CRIs of KF and LF provided adequate anesthetic conditions in dogs undergoing thoracolumbar hemilaminectomy. Based on requirement for rescue analgesia, postoperative analgesia was adequate in both groups. 相似文献
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Sanchez J Markham F Dohoo I Sheppard J Keefe G Leslie K 《Veterinary parasitology》2004,120(4):319-330
The present study was carried out to evaluate the relationship between milk optical density ratios (ODRs) from an indirect Ostertagia ostertagi ELISA, total milk IgG levels and milk production and then establish a correction factor to adjust ODR. Five hundred and sixty composite milk samples collected from 358 cows on four dairy herds in June and August 2002 were used in this analysis. The average ODR was 0.34. A positive correlation was found between ODR and IgG values in milk, days in milk, age and log transformed somatic cell counts (SCC). However, ODR was negatively correlated with milk production. The IgG levels and ODR values were constant from 30 to 200 days in milk. However, ODRs increased from 200 days until the end of the lactation. After controlling for age, season, herd and SCC, an increase in milk production of 13 kg/day was associated with a reduction in ODR values of 0.052. The results of the present study suggest that ODR values are not greatly influenced by production factors. ODR follow the same pattern as the IgG variation across lactation and could be adjusted in order to compare ODR values obtained from high producing cows with those obtained from low producing animals. 相似文献