SONOGRAPHIC STUDY OF GESTATION INRABBIT-DOE (ORYCTOLAGUS CUNICULUS) AND THE EFFECT OF ISONATION ON FETAL THYROID HORMONAL LEVEL

SONOGRAPHIC STUDY OF GESTATION INRABBIT-DOE (ORYCTOLAGUS CUNICULUS) AND THE EFFECT OF ISONATION ON FETAL THYROID HORMONAL LEVEL

Abstract:

Sixteen (16) mature non-gravid Does that had kittened at least once and at most thrice, had ultrasound (US)SV600® Ultrasound machine with a 6.5 MHz curvilinear transducer were used for the study. The experiment was designed to evaluate baseline information on the sonographic features of gestation in rabbit-doe and to investigate the effect of isonation on thyroid hormonal level of kittens upon parturition. All Does were scanned during the acclimatization period to ensure they were not gravid. They were all mated naturally by the introduction of a doe to a buck and then dividedrandomly into two groups A and B. Does in group B were scanned for an average of 5 minutes on the 5th day post coitus and thereafter on day 7, 12, 15, 20, 25, 27 and 29 while the procedure of scanning was mimicked in group A Does without isonation. After parturition, blood samples were collected from kittens of each litter via jugular venesection following light chloroform anaesthesia. Embryonic vesicles, seen as being small roundedanechoic (darkened) structures were first seen on day 7 of gestation. Hypoechoic structures within vesicles corresponding to embryo and placenta were seen on day 12 with an increase in size on day 15 of gestation. Bony formation, bi-parietal diameter (BPD), vertebral column, fetal heart and fetal heart rate were noted atadvanced gestation. The isonatedgroups were 100% pregnant at first to mid trimester. At term, only 12.5% remained pregnant. However, upon rebreeding 71.5% pregnancy success was achieved to parturition. Mean litter size and weight were 5.43 ± 0.9, 43.7 ± 4.3 g and 3.71 ± 0.7, 39.6 ± 2.1 g for the control and isonated group respectively. There was a statistical significant difference in the litter size and weight (P < 0.05). Mean Total Triiodothyronine (tT3) serum concentration was 1.60 ± 0.11 μg/dl and 1.58 ± 0.05 μg/dl respectively for control and isonated group while mean total Thyroxineserum concentration (tT4) was 1.44 ± 0.12 μg/dl and 1.39 ± 0.09 μg/dl for the control and isonated group respectively. The differences were not statistically significant (P > 0.05). There were vii nohistopathologic changes on fetal thyroid tissue of both groups. In conclusion, this study demonstrated that ultrasound can be used effectively to diagnose pregnancy in rabbit-doe as early as the 7th day of gestation. Frequent ultrasound exposure during pregnancy in does can result in an increase fetal death and reduce fetal size and weight. There is possibility of an increase threshold to ultrasound waves and ultrasound heating having effect on fetal hormone level especially in prolonged examination upon several isonation. This suggests that frequent isonation may not be entirely safe in pregnant does.

SONOGRAPHIC STUDY OF GESTATION INRABBIT-DOE (ORYCTOLAGUS CUNICULUS) AND THE EFFECT OF ISONATION ON FETAL THYROID HORMONAL LEVEL

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