Romano Juan E, Thompson James A, Forrest David W, Westhusin Mark E, Tomaszweski Michael A, Kraemer Duane C
Large Animal Clinical Sciences, College of Veterinary Medicine, Texas A&M University, College Station, TX 77845, USA.
Theriogenology. 2006 Sep 1;66(4):1034-41. doi: 10.1016/j.theriogenology.2006.02.044. Epub 2006 Apr 11.
The objective of the present study was to determine differences in time of detection of pregnancy between heifers and cows and the interval after insemination at which the maximum sensitivity and negative predictive value of transrectal ultrasonography were obtained. One-thousand-four-hundred transrectal ultrasonographies (TRUS-1; 1,079 in cows and 321 in heifers) were performed using a 5-MHz linear-array transducer. The cattle were randomly assigned to have TRUS performed once between days 24 and 30 (estrus=day 0) in cows or between days 21 and 27 in heifers. Every TRUS diagnosis was subsequently compared with a second TRUS diagnosis (TRUS-2), performed 3-8 days later, after day 30 (range 31-38) for cows and after day 27 (range 28-35) for heifers. The sensitivity and specificity between cows and heifers for the common days of TRUS (from 24 to 27) were compared. In cows, sensitivity increased gradually from 74.5% at day 24 to 100% at day 29 (P<0.01). Specificity increased from days 24-25 and reached a plateau of 96.6% on day 26 (P<0.01). In heifers, sensitivity increased from 50% at day 21 to 100% at day 26 (P<0.01). Specificity increased from 87.5% at day 21 and remained steady at 94% starting on day 23 (P>0.05). The sensitivity for cows and heifers was 89.2 and 96.8%, respectively (P<0.05) and the specificity was 93.0 and 93.4% (P>0.05). In this study, heifers were diagnosed pregnant earlier than cows, and the maximum sensitivity and negative predictive value were obtained 3 days earlier in heifers than cows (days 26 and 29, respectively).
本研究的目的是确定小母牛和母牛在检测到怀孕的时间上的差异，以及在授精后获得经直肠超声检查的最大敏感性和阴性预测值的时间间隔。使用5兆赫线性阵列换能器进行了1400次经直肠超声检查（TRUS-1；母牛1079次，小母牛321次）。牛被随机分配在母牛的第24至30天（发情期=第0天）或小母牛的第21至27天之间进行一次经直肠超声检查。随后，将每次经直肠超声检查诊断结果与3至8天后进行的第二次经直肠超声检查诊断结果（TRUS-2）进行比较，母牛在第30天后（范围31-38天），小母牛在第27天后（范围28-35天）。比较了母牛和小母牛在经直肠超声检查的共同天数（第24至27天）之间的敏感性和特异性。在母牛中，敏感性从第24天的74.5%逐渐增加到第29天的100%（P<0.01）。特异性从第24至25天增加，并在第26天达到96.6%的平台期（P<0.01）。在小母牛中，敏感性从第21天的50%增加到第26天的100%（P<0.01）。特异性从第21天的87.5%增加，并从第23天开始稳定在94%（P>0.05）。母牛和小母牛的敏感性分别为89.2%和96.8%（P<0.05），特异性分别为93.0%和93.4%（P>0.05）。在本研究中，小母牛比母牛更早被诊断出怀孕，并且小母牛比母牛提前3天获得最大敏感性和阴性预测值（分别为第26天和第29天）。
