The ultrasonographic image of an organ is a product of scattering and reflection of high-frequency ultrasound beams by discrete units of tissue. The number of acoustic tissue interfaces and vascularity affects the quantitative characteristics of grey-scale ultrasonographic images. This study was undertaken to examine the influences of scrotal/testicular integument and blood flow on testicular echotexture parameters in the ram. Serial ultrasonographic images were obtained during surgical castration of 7 Rideau Arcott rams aged 20–22 weeks. The first 2 sets of images were taken through the scrotum, prior to and after induction of anaesthesia. The third set was taken through the tunica vaginalis, the fourth set was obtained through the tunica albuginea, the fifth set was taken when the testicular cord and internal blood vessels were clamped, and the final set of images was recorded after allowing the blood to drain from dissected testicles (5 min). All images were then subjected to computerized image analyses and the testicles were processed for histology. The removal of the scrotal skin and tunica vaginalis both resulted in significant ( P < 0.05) increments in numerical pixel values (NPVs) and pixel heterogeneity (standard deviation of pixel values) of the testicular parenchyma. There were no differences ( P > 0.05) in testicular echotexture between images taken just before or after clamping the testicular cord vessels, or after draining. At all stages, NPVs were correlated ( P ≤ 0.10) to the seminiferous tubule (ST) area and the ST lumen area, except for NPVs and the ST lumen area in images obtained through the tunica albuginea ( P = 0.20). We concluded that: 1) attenuation of ultrasound waves by the scrotal skin and tunica vaginalis significantly altered testicular echotexture characteristics; 2) vascular blood flow did not affect the echotextural attributes of the rams’ testes; and 3) NPVs were a good indicator of ST microstructure in situ and ex vivo.

A Review of Advances in Artificial Insemination (AI) and Embryo Transfer (ET) in Sheep, with the Special Reference to Hormonal Induction of Cervical Dilation and its Implications for Controlled Animal Reproduction and Surgical Techniques

The primary goal of this study was to employ ultrasonography to examine the ovaries of ewes undergoing superovulatory treatment for correlations between antral follicular blood flow and ovarian responses/embryo yields. Five Santa Inês ewes were subjected to a short- (Days 0-6, Group 1) and five to a long-term progesterone-based protocol (Days 0-12, Group 2) to synchronize estrus and ovulations after the superovulatory treatment. Porcine FSH (pFSH, 200mg) was administered in 8 decreasing doses over 4 days, starting on Days 4 and 10 in Groups 1 and 2, respectively. After CIDR removal, all ewes were bred by a ram and embryos were recovered surgically 7 days later. Transrectal ovarian ultrasonography was performed the day before and on all 4 days of the superovulatory treatment. Both an arbitrary-scale [(0) non-detectable; (1) small; (2) moderate; (3) intense blood flow] and quantitative analysis of the blood flow area were used to assess the follicular blood flow in color Doppler images. There were no significant correlations between the arbitrary blood flow scores and superovulatory responses in the ewes of the present study. However, there was a positive correlation between the quantitative estimates of follicular blood flow on the final day of the superovulatory treatment, and the number (DA: r=0.68, P<0.05; DA/TA×100%: r=0.85, P<0.05) and percentage (DA: r=0.65, P<0.05; DA/TA×100%: r=0.91, P<0.001) of unfertilized eggs (DA: Doppler area, TA: total area of the largest ovarian cross section). This experiment presents a commercially practical tool for predicting superovulatory outcomes in ewes and evidence for the existence of follicular blood flow threshold that may impinge negatively on oocyte quality when surpassed during hormonal ovarian superstimulation.

Breeding soundness evaluation (BSE) is the primary assessment for determining the reproductive potential of male animals. This method, however, cannot be used to evaluate semen frequently or to predict future semen quality. Computerized analysis of ultrasonographic images provides information on histophysiological changes in male reproductive organs. We hypothesized that: (i) semen parameters would correlate with ultrasonographic characteristics of the distal region (cauda) of the epididymis and (ii) testicular ultrasound images and/or circulating testosterone concentration would predict future semen quality in the ram. Six adult rams underwent BSE and scrotal ultrasonography approximately 60 d apart (average duration of the spermatogenic cycle) both during the breeding (December and February) and non-breeding (June and August) seasons. An inverse correlation was found between pixel intensity (numerical pixel values) of the epididymes and percentage of sperm in semen with normal morphology ( r = −0.46, P < 0.05). Pixel heterogeneity (standard deviation of pixel values) correlated negatively with percentage of sperm with normal morphology ( r = −0.42, P < 0.05) and directly with percentage of spermatozoa with abnormal tails ( r = 0.43, P < 0.05). Pixel heterogeneity of testicular parenchyma obtained approximately 60 d prior to semen evaluation inversely correlated with percentage of sperm with normal morphology ( r = −0.73, P < 0.01) and sperm progressive motility ( r = −0.76, P < 0.01), and directly with percentage of sperm with abnormal tails ( r = 0.72, P < 0.01) and loose heads ( r = 0.79, P < 0.01). We concluded that scrotal ultrasonography combined with computer-assisted analyses of epididymal and testicular echotexture in the ram was a valuable method for determining certain current and future semen parameters, respectively.