Testicular thermography and seminal quality in bucks submitted to intermittent scrotal insulation in a tropical climate

Testicular degeneration is highly prevalent in ruminants reared in a tropical climate in Brazil. It is therefore necessary to assess semen quality periodically in this animals. The objective of this work was to define standards images (thermograms) by using infrared thermography (TIV), associated with computerized seminal evaluation (CASA) to predict testicular alterations in a non-invasive way. For this, 10 goat males were selected, and testis insulated to evaluate the seminal quality and testicular superficial temperature recorded in four different moments: before, during and early and later after insulation. Semen collections and rectal temperatures (TR) and superficial testis (TS) by TIV were assessed for 60 days after insulation. Data were expressed in media and standard errors and analysis of variation (ANOVA) with comparison between the moments using Tukey test at 5% of probability. Changes in seminal quality followed the same standard of changes in TS, with no influence of the latter one on rectal temperature. The mean testicular temperature increased more than 2 degrees above the normal mean testis temperature, with significant increasing (p <0.05) in the moment during in relation to the moments before and post insulation, and concomitantly reduction in seminal parameters and almost normal return to 60 days post insulation. These changes in testis surface temperatures associated with semen analysis allowed to get patterns images of testicular degeneration, permitting to predict by TIV testis alterations for later assess of seminal quality.

PSII-33 Mitigation of testicular heat stress in boars with PG600

Testicular heat stress due to increasing summer temperatures negatively impacts spermatogenesis reducing semen quality in boars. Scrotal insulation (SI) can mimic summer heat stress. Our hypothesis is that PG600 can mitigate heat stress in boars. PG600 is human chorionic gonadotropin (HCG) and equine chorionic gonadotropin (ECG) which have LH- and FSH-like effects respectively. During spermatogenesis, LH impacts testosterone production by Leydig cells and FSH impacts Sertoli cells to produce androgen receptors, inhibit apoptotic signals and sustain spermatogenesis. Eight boars (8–12 months of age) were randomly assigned to two treatment groups: SI + saline or SI + PG600. The SI was applied for 48 hrs. Injections were administered 24 hrs prior to SI application and again at onset of SI. PG600 was given at a standard gilt dose to induce puberty. Semen was collected every M-W-F for two weeks prior to treatment and 44 days post-treatment. Semen was evaluated for nuclear head shape via Fourier harmonic analysis (FHA) described as Harmonic amplitudes 0–5 (HA0-5). Semen for each collection day post-treatment was compared to the average of the semen collection days pre-treatment, described as day 0. Scrotal insulation produced a 3.7°C increase in average scrotal temperature for 48 hrs. Post-SI + saline, HA0 decreased on days 21–33 (P &lt; 0.05), HA1 increased on day 30 (P &lt; 0.05), HA2 decreased on day 35 (P &lt; 0.05), HA3 increased on days 21–33 (P &lt; 0.05), HA4 increased on days 21–26 (P &lt; 0.05), and HA5 increased on days 21–30 (P &lt; 0.05). Post-SI + PG600, decreased the number of days post-SI when changes in harmonic amplitudes were seen (P &lt; 0.05) as well as the magnitude of the response (P &lt; 0.05). PG600 was for the first time shown to significantly mitigated the response of boars to SI and testicular heat stress. Increased doses of PG600 may improve results.

Antisperm antibodies and sperm function in bulls undergoing scrotal insulation

Bovine antisperm antibodies (ASAs) have been associated with teratospermia and asthenospermia. It was hypothesized here that scrotal insulation induces the formation of ASAs and deterioration of sperm function. Scrotal insulation bags were placed in 10 bulls for 8 days. Semen was collected on days −29, −22 and −2, twice weekly from days 5 to 54, and thereafter weekly until day 96 (day 0 = first day of scrotal insulation). On each collection day, scrotal circumference, sperm motility, morphology, membrane integrity, acrosome integrity, apoptosis, lipid peroxidation, mitochondrial membrane potential, ASA binding and DNA integrity were evaluated. The percentage of IgG- and IgA-bound sperm increased between days 12 and 96 (P < 0.0001), in association with poor motility (days 19–30, P < 0.005) and morphology (days 8–40, P < 0.0001). Mean scrotal circumference decreased between days 15 and 75 (P < 0.0001). There was also a deterioration in sperm membrane integrity (days 19–40, P < 0.0001), acrosome integrity (days 26–89, P < 0.0001), lipid peroxidation (days 5–12, P < 0.0001), and mitochondrial membrane potential (days 12–96, P = 0.001). In contrast, a decrease in apoptotic cells (days 37–83, P = 0.0002) and lipid peroxidation (days 19–96, P < 0.0001) was noticed. Most bulls recovered normospermia by day 96. However, the persistence of ASAs, acrosomal damage and dysfunctional mitochondria suggest a long term effect of scrotal insulation on sperm function and the homeostasis of the reproductive immune system.

Effect of racial crossing on the seminal parameters of rams submitted to heat stress

The aim of this study was to evaluate the effect of racial crossing on seminal parameters of eight Santa Inês and crossbred (Santa Inês x Dorper) rams submitted to heat stress, and to monitor the return of these parameters to previously reported. Before to place the insulation bags, two collects of semen through electroejaculation were performed. The insulation pouches were made with double-layer plastic, internally lined with cotton, and fixed around the spermatic funiculus and scrotum with adhesive tape and bandage remaining on the testes of the animals for seven days. The first collect was performed on the day that the pouches were taken (day 0) and thereafter, every seven days, totalizing 15 measurements. Data were submitted to analysis of variance (ANOVA). The analyzed variables were subjected to Dunnett test at 5% probability to compare the values obtained before treatment with those obtained in the following days. In this study it was found that the animals restored normal seminal parameter after the insulation effects, however, the return rate differed slightly among the studied breeds. The crossbred animals restored the seminal patterns, on average, a week before Santa Inês. It is concluded that the racial crossing influences the semen parameters of rams submitted to heat stress. Keywords: motility, scrotal insulation, sperm concentration, sperm quality.

Infrared thermography and Doppler ultrasonography to evaluate the effects of scrotal insulation on testicular blood flow dynamics in bulls

The aim of this study was to evaluate the dynamics of the scrotal temperature, sperm quality and testicular blood flow by using infrared thermography and Doppler ultrasonography in bulls submitted to scrotal insulation. Braford bulls (n = 8) at 18 months of age, were assigned into the following groups: insulated for 72 h (G 72; n = 2), 96 h (G 96, n = 2), 120 h (G 120, n = 2), and control animals (CON; n = 2) that remained without insulation. Infrared thermography and Doppler ultrasonography parameters were measured at four different time points: immediately after the scrotal insulation (M0), within 10 min (M10), 30 min (M30) and 60 min (M60) after scrotal insulation. The sperm quality was evaluated weekly (S1/S12). The data were analyzed by ANOVA, t-test (paired) and Pearson's correlation with a significance level of 5%. None of the observed variables were different between the insulated groups (P > 0.05). Insulated animals showed higher scrotal temperature in M0 compared to that in the M10, M30 and M60 periods (P < 0.05). There was no difference in the pulsatility and resistive indexes after scrotal insulation. However, blood flow velocity was higher in M10 compared to that in the M0, M30 and M60 periods (P < 0.05). The sperm quality was higher (P < 0.05) in all twelve collections from the control group compared with the insulated groups. Scrotal insulation resulted in changes in the sperm quality, scrotal temperature and testicular blood flow velocity.