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.

Infrared thermography and Doppler ultrasonography to evaluate the effects of scrotal insulation on testicular blood flow dynamics in bulls / Termografia infravermelho e ultrassonografia Doppler na avaliação dos efeitos da insulação escrotal sobre o fluxo sanguíneo testicular em touros

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.(AU)

O objetivo deste estudo foi avaliar a dinâmica da temperatura escrotal, a qualidade espermática e o fluxo sanguíneo testicular utilizando a termografia infravermelho e a ultrassonografia Doppler em touros submetidos a insulação escrotal. Touros Braford (n=8) aos 18 meses de idade, foram distribuídos nos seguintes grupos: insulados por 72 h (G 72; n=2), 96 h (G 96; n=2), 120 h (G120, n=2), e animais controle (CON; n=2) que permaneceram sem insulação. Os parâmetros de termografia infravermelha e ultrassonografia Doppler foram medidos em quatro diferentes momentos: imediatamente após a insulação escrotal (M0), aos 10 min (M10), 30 min (M30) e 60 min (M60) após a insulação escrotal. A qualidade espermática foi avaliada semanalmente (S1 / S12). Os dados foram analisados por ANOVA, teste t (pareado) e correlação de Pearson com nível de significância de 5%. Nenhuma das variáveis observadas foi diferente entre os grupos insulados (P > 0,05). Os animais insulados apresentaram maior temperatura escrotal em M0 quando comparados aos M10, M30 e M60 (P < 0,05). Não houve diferença nos índices de pulsatilidade e resistividade após a insulação escrotal. No entanto, a velocidade do fluxo sanguíneo foi maior em M10 em relação aos períodos M0, M30 e M60 (P < 0,05). A qualidade espermática foi maior (P < 0,05) em todas as doze coletas do grupo controle em comparação com os grupos insulados. A insulação escrotal resultou em mudanças na qualidade espermática, temperatura escrotal e na velocidade do fluxo sanguíneo testicular.(AU)

Evaluation of scrotal temperature in different testicular shapes by infrared thermography in Braford bulls

Background: The mechanisms of testicular thermoregulation may influence the blood flow provided by the testicularartery, where the proper blood supply to the testicle is crucial for promotingspermatogenesis and reproductive functionin bulls. The size and shape of the testicles are determined by genetic mechanisms and environmental effects. A betterunderstanding of the relationships between the anatomical characteristics of the testicles and scrotum can support a betterreproductive assessment. The purpose of the current study was to evaluate the testicular temperature of different scrotalshapes using infrared thermography in bulls.Materials, Methods & Results: We evaluated 132 Braford bulls with an average age of 24 months. The evaluation of breeding bull semen was performed prior to the beginning of the experiment. Then, animals were selected on the basis of the sizeof their testes, which was determined by dividing the average width by the average length. The scrotal circumference wasmeasured with a millimeter tape positioned around the largest circumference. Testicular and ocular temperature measurementsand analysis were conducted using an infrared thermal camera, Flir T440 with emissivity of 0.98 and thermal sensitivity of0.05°C. Testicular scrotum temperature and testicular shape were analyzed with one-way ANOVA using Minitab 16, andvalues of P < 0.05 were considered statistically significant. We observed that 67.42% of testicle shapes were long-oval,and 32.58% were long-moderate. The testicular temperature was higher in bulls with the long-moderate shape comparedto those with the long-oval shape (P < 0.05). The mean length was higher in long-moderate shaped testicles compared tothose of the long-oval shape (P < 0.01). There was no significant differences...(AU)

Heritability estimation and genetic correlations for mature weight, visual scores, and growth traits in Nellore cattle

This study was intended to estimate the genetic associations between growth traits and visual scores with possible changes in mature weight (MW) in 397,900 Nellore animals. A bi-character analysis was performed to estimate the (co)variances and genetic parameters for MW, which comprises the following traits: conformation, finishing precocity, musculature at weaning (WC, WP, and WM) and yearling (YC, YP, and YM), birth weight (BW), weight from birth to weaning (WG), weight from weaning to yearling (YG), and final index (FIND). The observed mean MW was 417.6±56.2 kg, and the direct genetic effect mean estimated heritability (h²a1) of MW was 0.45. Overall, the BW was 31.0±3.7 kg, and the estimated h² was 0.34. The heritability estimate of the maternal additive genetic component (h²m2) of BW was 0.07. We calculated the mean WG to be 144.1±26.3 and estimated the h²a2 as 0.18 and h²m2 as 0.07. The value for h²a YG (0.17) and YW (0.26) were also estimated. The heritability of the weaning WC (0.17), WP (0.19), and WM (0.17) and yearling YC (0.25), YP (0.27), and YM (0.25) were estimated using visual scores. The h²m values for weaning WC, WP, and WM (0.06) with visual scores were estimated. The genetic correlations between body weight (BoW) at YC and WC (0.62) were considered moderately high and positive. In addition, YP (0.18), YM (0.15), WP (0.13), and WM (0.14) were considered moderately low compared with MW. The genetic correlation between BW and FIND (0.38) was considered positive and moderate. The heritability estimation indicates that growth traits, visual scores, and weight of adult cows could be changed by selection. Cows that presented the highest h²a values for live weight responded rapidly to selection based on growth characteristics, visual scores, and FIND and might result in increased final MW.(AU)

Evaluation of scrotal temperature in different testicular shapes by infrared thermography in Braford bulls

Background: The mechanisms of testicular thermoregulation may influence the blood flow provided by the testicularartery, where the proper blood supply to the testicle is crucial for promotingspermatogenesis and reproductive functionin bulls. The size and shape of the testicles are determined by genetic mechanisms and environmental effects. A betterunderstanding of the relationships between the anatomical characteristics of the testicles and scrotum can support a betterreproductive assessment. The purpose of the current study was to evaluate the testicular temperature of different scrotalshapes using infrared thermography in bulls.Materials, Methods & Results: We evaluated 132 Braford bulls with an average age of 24 months. The evaluation of breeding bull semen was performed prior to the beginning of the experiment. Then, animals were selected on the basis of the sizeof their testes, which was determined by dividing the average width by the average length. The scrotal circumference wasmeasured with a millimeter tape positioned around the largest circumference. Testicular and ocular temperature measurementsand analysis were conducted using an infrared thermal camera, Flir T440 with emissivity of 0.98 and thermal sensitivity of0.05°C. Testicular scrotum temperature and testicular shape were analyzed with one-way ANOVA using Minitab 16, andvalues of P < 0.05 were considered statistically significant. We observed that 67.42% of testicle shapes were long-oval,and 32.58% were long-moderate. The testicular temperature was higher in bulls with the long-moderate shape comparedto those with the long-oval shape (P < 0.05). The mean length was higher in long-moderate shaped testicles compared tothose of the long-oval shape (P < 0.01). There was no significant differences...

Genetic trends for mature body weight, visual scores, and growth traits in Nellore cattle / Tendência genética para peso adulto, escores visuais e características de crescimento em bovinos de corte da raça Nelore

Mature weight (MW) of cows is related to the costs of their production. Usually, cows with moderate MW are more efficient in challenging environments, such as those available in the production systems in Brazil. In the present study, the selection index comprises the following traits: conformation, finishing precocity, musculature at weaning (WC, WP, WM) yearling (YC, YP and YM), scrotal circumference at yearling (SC), days to gain 160kg from birth to weaning (D160) and 240kg after weaning (D240). This are related to birth weight gain at weaning (WG) and from weaning to yearling (YG). The mature (MW) and birth weight (BW) traits were not considered in the selection index. The aim of this study was to estimate the values for the genetic trends (GT) of some important selection (MW) and economic traits (BW). A bi-character analysis of MW and other characteristics was performed to estimate the (co)variance components and genetic parameters. The GT results obtained for MW were null (0.0065% or 0.02718kg per year) in the period 1990-2007. The GT values were determined for BW (-0.0650% or -0.02017kg), WG (0.0758% or 0.0865kg), YG (0.1051% or 0.11377kg), and MW (0.0393% or 0.11276kg) per year. The visual score values (in score units) were also determined for GTat weaning [WC (0.2310%; 0.00707), WP (0.3624%; 0.3623%),aWM (0.01149; 0.01087)] yearling [YC (0.3256%; 0.00990), YP (0.4795%; 0.01496),YM (0.5041%; 0.01457)] per year. Index-based selection was effective to promote genetic progress in WG, WC, WP, WM, YG, YC, YP, and YM characteristics keeping BW and MW constant.

O peso adulto das vacas (PV) está relacionado com os custos de produção. Em geral, vacas com PV moderados são mais eficientes em ambientes desafiadores, como aqueles disponíveis nos sistemas de produção no Brasil. No presente estudo, o índice de seleção compreende as seguintes características: conformação, precocidade e musculatura nas fases da desmama (CD, PD e MD) e sobreano (CS, PS e MS), circunferência escrotal no sobreano (CE), dias para ganhar 160kg do nascimento até a desmama (D160) e 240kg pós-desmama (D240), que estão relacionadas com os ganhos de peso do nascimento à desmama (GD) e, da desmama ao sobreano (GS). As características PV e PN não foram consideradas no índice de seleção. O objetivo deste estudo foi estimar os valores das tendências genéticas (TG) das importantes características de seleção (PV) e econômicas (PN). Para estimar os componentes de (co)variâncias e os dados genéticos, foram realizadas análises bi-caracter de PV com as demais características. Os resultados de TG obtidos para PV foram nulos (0,0065% ou 0,02718kg por ano) no período de 1990 á 2007. Os valores de TG foram estimados para PN (-0,0650% ou -0,02017kg), GD (0,0758% ou 0,0865kg), GS (0,1051% ou 0,11377kg) e PF (0,0393% ou 0,11276kg) por ano. Os valores dos escores visuais (em unidades de escore) foram determinados para TG à desmama [CD (0,2310%; 0,00707), PD (0,3624%; 0,3623%) e MD (0,01149; 0,01087)] e sobreano [CS (0,3256%; 0,00990), PS (0,4795%; 0,01496) e MS (0,5041%; 0,01457)] ao ano. A seleção baseada no índice foi efetiva para promover o progresso genético nas características de GD, CD, PD, MD, GS, CS, PS e mantendo PN e PV constantes.

Genetic trends for mature body weight, visual scores, and growth traits in Nellore cattle / Tendência genética para peso adulto, escores visuais e características de crescimento em bovinos de corte da raça Nelore

Mature weight (MW) of cows is related to the costs of their production. Usually, cows with moderate MW are more efficient in challenging environments, such as those available in the production systems in Brazil. In the present study, the selection index comprises the following traits: conformation, finishing precocity, musculature at weaning (WC, WP, WM) yearling (YC, YP and YM), scrotal circumference at yearling (SC), days to gain 160kg from birth to weaning (D160) and 240kg after weaning (D240). This are related to birth weight gain at weaning (WG) and from weaning to yearling (YG). The mature (MW) and birth weight (BW) traits were not considered in the selection index. The aim of this study was to estimate the values for the genetic trends (GT) of some important selection (MW) and economic traits (BW). A bi-character analysis of MW and other characteristics was performed to estimate the (co)variance components and genetic parameters. The GT results obtained for MW were null (0.0065% or 0.02718kg per year) in the period 1990-2007. The GT values were determined for BW (-0.0650% or -0.02017kg), WG (0.0758% or 0.0865kg), YG (0.1051% or 0.11377kg), and MW (0.0393% or 0.11276kg) per year. The visual score values (in score units) were also determined for GTat weaning [WC (0.2310%; 0.00707), WP (0.3624%; 0.3623%),aWM (0.01149; 0.01087)] yearling [YC (0.3256%; 0.00990), YP (0.4795%; 0.01496),YM (0.5041%; 0.01457)] per year. Index-based selection was effective to promote genetic progress in WG, WC, WP, WM, YG, YC, YP, and YM characteristics keeping BW and MW constant. (AU)

O peso adulto das vacas (PV) está relacionado com os custos de produção. Em geral, vacas com PV moderados são mais eficientes em ambientes desafiadores, como aqueles disponíveis nos sistemas de produção no Brasil. No presente estudo, o índice de seleção compreende as seguintes características: conformação, precocidade e musculatura nas fases da desmama (CD, PD e MD) e sobreano (CS, PS e MS), circunferência escrotal no sobreano (CE), dias para ganhar 160kg do nascimento até a desmama (D160) e 240kg pós-desmama (D240), que estão relacionadas com os ganhos de peso do nascimento à desmama (GD) e, da desmama ao sobreano (GS). As características PV e PN não foram consideradas no índice de seleção. O objetivo deste estudo foi estimar os valores das tendências genéticas (TG) das importantes características de seleção (PV) e econômicas (PN). Para estimar os componentes de (co)variâncias e os dados genéticos, foram realizadas análises bi-caracter de PV com as demais características. Os resultados de TG obtidos para PV foram nulos (0,0065% ou 0,02718kg por ano) no período de 1990 á 2007. Os valores de TG foram estimados para PN (-0,0650% ou -0,02017kg), GD (0,0758% ou 0,0865kg), GS (0,1051% ou 0,11377kg) e PF (0,0393% ou 0,11276kg) por ano. Os valores dos escores visuais (em unidades de escore) foram determinados para TG à desmama [CD (0,2310%; 0,00707), PD (0,3624%; 0,3623%) e MD (0,01149; 0,01087)] e sobreano [CS (0,3256%; 0,00990), PS (0,4795%; 0,01496) e MS (0,5041%; 0,01457)] ao ano. A seleção baseada no índice foi efetiva para promover o progresso genético nas características de GD, CD, PD, MD, GS, CS, PS e mantendo PN e PV constantes. (AU)