Nation D P, Malmo J, Davis G M, Macmillan K L
Department of Veterinary Science, University of Melbourne, Werribee, Victoria 3030.
Aust Vet J. 2003 Jan-Feb;81(1-2):63-5. doi: 10.1111/j.1751-0813.2003.tb11435.x.
To estimate the accuracy of real-time ultrasonography to detect pregnancy in dairy cows at 28 to 35 days after insemination.
Cows that did not return to oestrus between 18 and 24 days after a first insemination (n = 526) were examined by transrectal ultrasonography from 28 to 35 days after insemination. Pregnancy was confirmed by the observation of a foetus, but fluid in the uterine horn and the presence of embryonic membranes were also noted. When pregnancy was not confirmed by the observation of a foetus, a second examination 7 days later, confirmed these remaining cows as pregnant or not pregnant to the first insemination. Detection of pregnancy at this early examination was compared with manual transrectal pregnancy examination performed 10 to 13 weeks after insemination (13-week examination).
There were 44% of cows that were pregnant to the first service, 34% that had returned for a second service 18 to 24 days after the first insemination, and 20% of cows that were not pregnant, and had not returned normally for a second service (non-pregnant, non-return) within 24 days of their initial insemination. The presence of a foetus at 28 to 35 days after insemination was accurately predicted by a simplified method where uterine fluid accumulation and embryonic membranes were observed. Foetal loss between the early detection and the 13-week examination (9% of pregnancies) indicated that 28 to 35 days post insemination was too early to reliably detect pregnancy.
Early examination of pregnancy with transrectal ultrasonography is an accurate method to identify non-pregnant, non-return cows. The examination can be simplified by the observation of uterine fluid accumulation and embryonic membranes, as opposed to the more involved process of observing the foetus.
评估实时超声检查在奶牛人工授精后28至35天检测妊娠的准确性。
首次人工授精后18至24天未发情的奶牛（n = 526）在人工授精后28至35天接受经直肠超声检查。通过观察胎儿确认妊娠，但也记录子宫角内的液体和胎膜的存在。当未通过观察胎儿确认妊娠时，7天后进行第二次检查，确认这些剩余奶牛首次人工授精是否妊娠。将此次早期检查的妊娠检测结果与人工授精后10至13周进行的经直肠手动妊娠检查（13周检查）进行比较。
44%的奶牛首次输精妊娠，34%在首次人工授精后18至24天进行了第二次输精，20%的奶牛未妊娠且在初次人工授精后24天内未正常进行第二次输精（未妊娠，未返情）。通过观察子宫积液和胎膜的简化方法能够准确预测人工授精后28至35天胎儿的存在。早期检测和13周检查之间的胎儿丢失（占妊娠的9%）表明人工授精后28至35天检测妊娠过早，无法可靠检测。
经直肠超声早期检查妊娠是识别未妊娠、未返情奶牛的准确方法。与观察胎儿的更复杂过程相比，通过观察子宫积液和胎膜可简化检查。
