Testicular shape, scrotal skin thickness and testicular artery blood flow changes in bulls of different ages.

The aim of this study was to compare the biometric testicular characteristics, skin thickness and haemodynamics of the testicular artery of 12- and 24-month-old bulls using Doppler ultrasonography, the study was conducted using 48 indicus-taurus animals. The scrotal circumference (SC) and biometry characteristics of the bulls were measured to calculate the testicular volume. Doppler ultrasonography was used to obtain the haemodynamic values of the testicular artery. The skin thickness and volume were lower (p<.01) in the younger bulls (12 months:4.68 ± 0.68 mm; 168.76 ± 47.96 cm3 ) versus 24 months (5.05 ± 0.89; 499.73 ± 129.24 cm3 ) animals (p<.01). During diastole, mean velocity was lower in the 12 months (7.98 ± 3.83) than in the 24 months (11.37 ± 4.15) animals (p <.05). The 12-month-old animals had higher pulsatility and resistivity indices (0.49 ± 0.02; 0.51 ± 0.20) compared to the 24-month-old animals (0.32 ± 0.16; 0.40 ± 0.15) (p < .05). The final testicular end velocity was lower in animals with long/moderate-shaped (L/M) (7.31 ± 2.91) than in those moderate/oval-shaped (M/O) (11.48 ± 3.88) testicles (p < .05). Animals with L/M testes presented higher pulsatility values and resistivity indices (0.51 ± 0.05; 0.55 ± 0.04) compared to animals with M/O shape (0.29 ± 0.20; 0.36 ± 0.15). We showed that the blood flow of the supra testicular artery between the two evaluated ages differed, and that 24-month-old bulls presented better thermoregulation capacity. Animals with a long/moderate testicular format presented a greater vascular resistance, which was imposed on the blood flow due to the anatomical differences in the testicular artery, resulting in lower velocity, and indicating better heat dissipation in this format.

Effect of breed on testicular blood flow dynamics in bulls.

The evaluation of testicular hemodynamics can contribute significantly to the understanding of the thermoregulatory mechanisms and oxygen supply of the testis in domestic animals. The present study aimed to characterize circulatory dynamics using the mean velocity (MV), pulsatility index (PI) and resistive index (RI) of the supratesticular artery in bulls. We evaluated 334 bulls of five different breeds (Nelore, Hereford, Aberdeen Angus, Braford and Brangus) by performing a velocimetry analysis using Doppler ultrasonography. Data were compared by Welch's ANOVA, Games-Howell (post-hoc test) and Spearman correlation with a significance level of 5%. The overall MV of 12.14 ±â€¯0.30 cm/s differed among breeds. In addition, we observed that Brangus bulls showed higher (P < 0.05) MV (16.28 ±â€¯1.02 cm/s) compared to Nelore bulls (8.76 ±â€¯0.40 cm/s). The RI had an overall mean of 0.41 ±â€¯0.01 and differed among breeds. We observed higher (P < 0.05) RI values in Hereford (0.44 ±â€¯0.01) compared to Brangus (0.36 ±â€¯0.02) animals. Overall, the PI values (0.33 ±â€¯0.01) did not differ (P > 0.05) among breeds. The correlation between the PI and RI (0.936; P < 0.001) was high and positive; however, the correlations were low and negative between MV and the PI (-0.228; P < 0.001) and between MV and the RI (-0.270; P < 0.001). We concluded that there are differences in the MV and RI of the bulls' supratesticular arteries among the different evaluated breeds. Moreover, the presented values attributed to blood flow dynamics can serve as parameters in future studies and can be used to identify alternative diagnostic tools for infertility or to understand issues of adaptability in bulls.

Infrared thermography relationship between the temperature of the vulvar skin, ovarian activity, and pregnancy rates in Braford cows.

The objective of this study was to compare the presence of ovarian activity and pregnancy rates to temperature variation at the vulvar skin measured by infrared thermography (IRT). In addition, we also aimed to evaluate the IRT as a non-invasive method to evaluate animal breeding from fixed timed artificial insemination (FTAI). The study comprises 150 non-lactating beef Braford cows (5/8 Hereford × 3/8 Nellore) aged between 3 and 10 years. Data were collected along the FTAI protocol period during animal management. Animals were subjected to reproductive ultrasound evaluation and thermal images were performed by an infrared camera. Mean skin vulvar temperature (°C) and ovarian structures data were compared using Tukey's t test used as follow-up test to ANOVA. We observed a statistical difference in the mean vulvar skin temperature between animals that had the presence of ovarian follicles (34.2 ± 1.8) compared to no activity (35.4 ± 1.0; P < 0.05). However, vulvar skin temperature were similar between pregnant (34.5 ± 1.5) compared to non-pregnant (34.3 ± 1.9) animals (P > 0.05). In conclusion, the IRT technique was efficient to detect changes on vulvar skin temperature observed during FTAI protocol in Braford cows. Therefore, the use of IRT as an indirectly diagnostic tool to detect ovarian activity seems promising and further studies are required to validate their potential in beef cattle production.