336 COMPARISON OF FETAL DEVELOPMENT AND FETAL HEARTBEAT BY ULTRASONOGRAPHY IN ARTIFICIALLY INSEMINATED AND EMBRYO-TRANSFERRED DAIRY COWS
K. Kishida A , N. Shibata A , K. Hata A , S. Aoki A , T. Nishisouzu A , O. Dochi A and H. Koyama AADepartment of Daily Science, Rakuno Gakuen University. Email: dochi@rakuno.ac.jp
Reproduction, Fertility and Development 17(2) 319-319 https://doi.org/10.1071/RDv17n2Ab336
Submitted: 1 August 2004 Accepted: 1 October 2004 Published: 1 January 2005
Abstract
Bovine fetal size and fetal heartbeat are important factors for detecting abnormal pregnancies in artificially inseminated and embryo-transferred dairy cows. The purpose of this study was to compare fetal growth and fetal heartbeat by transrectal ultrasonography in the early pregnancy of artificially inseminated (AI) and embryo-transferred (ET) dairy cows. The pregnancies of 86 animals were examined by fetal heartbeat count (n = 35 per animal of AI versus n = 51 per animal of ET) every 5 days from 35 to 60 days after breeding (the day of ovulation = day 0). The pregnancies of 237 animals were measured by fetal crown-rump length (n = 95 per animal of AI versus n = 142 per animal of ET) at 30 days and 60 days after breeding. Built-in electronic calipers were used to measure fetal dimensions on the ultrasonic screen. In addition, the times of first fetal heartbeats were recorded. Data were analyzed using ANOVA. The results are presented in the Table (Values were mean ± SD except for No. of animals). There were no differences in the range of fetal heartbeat for AI and ET (161.0 to 185.3 beats min−1 versus 169.7 to 184.6 beats min−1). However, fetal heartbeats of AI at 35 days of gestation was higher (P < 0.05) than those in cows at days 40, 45, 50, 55 and 60 of gestation (185.3 ± 8.7 beats min−1 versus 161.0 ± 9.5, 165.0 ± 19.5, 170.3 ± 26.8, 169.4 ± 27.8, and 171.2 ± 11.9 beats min−1, respectively). There were no differences in fetal crown-rump length between AI and ET. The prediction equation for crown-rump length in relation to fetal age of AI was y = 0.0046x2 − 0.2452x + 4.4424, R2 = 0.9643, while that for ET was y = 0.0049x2 − 0.2699x + 4.9396, R2 = 0.9728. Crown-rump length at 30 days and 60 days of gestation did not differ between AI and ET (1.2 ± 0.1 cm versus 1.2 ± 0.1 cm, 6.4 ± 0.3 cm versus 6.5 ± 0.4 cm, respectively). In conclusion, there were no differences in fetal development and heartbeats between AI and ET dairy cows. In addition, there were no differences in fetal crown-rump length between AI and ET dairy cows.
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