Effect of scrotal insulation on sperm quality and seminal plasma proteome of Brangus bulls.

Seminal plasma (SP) contributes to sperm physiology and metabolism, prevents premature capacitation, and protects sperm against oxidative stress. In order to evaluate the impact of heat stress in the semen of tropically adapted Brangus breed and in their seminal plasma proteome, we studied the effects of scrotal insulation for 72 h. Semen samples from six bulls, between 7 and 8 years of age, were collected prior to scrotal insulation (pre-insulation), and at 4 and 11 wk after insulation. Seminal plasma samples were analyzed by 2D SDS-PAGE and liquid chromatography coupled with mass spectrometry (LC-MS/MS). Insulation caused decrease in vigour, gross and total motility after 4 wk of scrotal insult (P < 0.001). Total defects in sperm were higher after 4 wk compared to pre-insulation and 11 wk after scrotal insulation (P < 0.001). The analysis of the 2D protein profile of the SP resulted in the identification 183 unique protein spots in all gels evaluated. There was no difference in mean number of protein spots amongst time points. Eight protein spots were more abundant in SP after scrotal insulation, returning to the same expression level at 11 wk post-insulation. One spot had higher abundance at 11 wk post-insulation, and one spot had decreased abundance 4 wk after insulation. The ten protein spots with differential abundance amongst time points were identified as Seminal plasma protein PDC-109, Seminal plasma protein A3, Seminal plasma protein BSP-30 kDa, Spermadhesin-1 and Metalloproteinase inhibitor 2. The validation of these five proteins as biomarkers for thermal testicular stress in Brangus breed would allow the development of new biotechnologies that could improve bovine semen analysis in breeding systems in tropical and subtropical conditions. A close association between the identified BSP and Spermadhesin-1 was evidenced in protein-protein interaction analysis. Based on gene ontology analysis, variation in sperm function after insulation could be explained by variation in the expressed proteins in the SP. Further studies are required to verify if these proteins could be used as biomarkers for the identification of bulls with increased seminal resistance to heat stress in Brangus breed.

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.

Effects of ambient air temperature, humidity, and wind speed on seminal traits in Braford and Nellore bulls at the Brazilian Pantanal.

The aim of this study was to evaluate the bioclimatic thermal stress assessed by Equivalent Temperature Index (ETI) and Temperature Humidity Index (THI) on Braford and Nellore bulls sperm quality during the reproductive seasons at the tropical region in the Brazilian Pantanal. We used 20 bulls aged approximately 24 months at the beginning of the study. Five ejaculates per animal were collected using an electroejaculator. Temperature, air humidity, and wind speed data were collected every hour from the automatic weather station at the National Institute of Meteorology. Infrared thermography images data were collected to assess the testicular temperature gradient in each animal. Data were analyzed with ANOVA using MIXED procedure of SAS and means were compared using Tukey's HSD test. The THI and ETI at 12 days (epididymal transit) were higher in January (89.7 and 28.5, respectively) and February (90.0 and 29.0, respectively) compared to other months (P < 0.01). Total seminal defects differ only in Bradford bulls between the months of November and February. Nellore bulls had lower major defects (MaD) and total defects (TD) compared to Braford. Nellore bulls showed correlation between minor defects (MiD) and THI for 30 days (0.90) and 18 days (0.88; P < 0.05). Braford bulls showed correlation for MaD (0.89) in ETI for 12 days (P < 0.05). Infrared thermography showed no difference between animals. Reproductive response to environmental changes is a consequence of Nellore and Braford adaptation to climate stress conditions. Both THI and ETI environmental indexes can be used to evaluate the morphological changes in the seminal parameters in Nellore or Braford bulls; however, more experiments should be performed focusing on larger sample numbers and also in reproductive assessment during the consecutive years to assess fertility potential.

The uses of infrared thermography to evaluate the effects of climatic variables in bull's reproduction.

The objective of this study was to evaluate the seasonal effects of the environment on sperm quality in subtropical region determined by temperature and humidity index (THI). We used 20 Brangus bulls (5/8 Angus × 3/8 Nellore) aged approximately 24 months at the beginning of the study. Semen evaluations were performed twice per season during 1 year. Climate THI data were collected from an automatic weather station from the National Institute of Meteorology. Infrared thermography images were used to determine the temperature of the proximal and distal poles of the testis to assess the testicular temperature gradient (TG). The seasonal effects on seminal and climatic variables were analyzed with ANOVA using MIXED procedure of SAS. Sperm motility in spring (60.1%), summer (57.6%), and autumn (64.5%) showed difference compared to winter (73.0%; P < 0.01). TG was negatively correlated with THI at 18 days (spermiogenesis) (-0.76; P < 0.05) and at 12 days (epididymal transit) (-0.85; P < 0.01). Ocular temperature (OcT) had a positive correlation with THI at 18 days (0.78; P < 0.05) and at 12 days (0.84; P < 0.01). Motility showed a negative correlation with THI only at 18 days (-0.79; P < 0.05). During spermiogenesis, the TG had higher negative correlation compared to OcT (-0.97; P < 0.01) and rectal temperature (-0.72; P < 0.05). Spermatozoa with distal midpiece reflex were correlated with THI during transit epididymis (0.72; P < 0.05). Seminal parameters are not affected when THI reaches 93.0 (spermiogenesis) and 88.0 (epididymal transit). We concluded that infrared thermography can be adopted as an indirect method in order to assess the effect of environmental changes in TG and OcT of Brangus bulls.

Scrotal infrared digital thermography as a predictor of seasonal effects on sperm traits in Braford bulls.

The aim of this study was to assess the seasonal effects of the environment on semen quality in bulls, using infrared thermography. Sperm motility (M), mass motion (MM), and vigor (VIG) were evaluated in sperm samples from 17 Bradford bulls aged approximately 24 months at the beginning of the study. Infrared thermography images and data were collected using an infrared FLIR T 300 camera and Quick Report 1.2 SP2 software to determine the temperature of the proximal and distal poles of the testis and to assess the testicular temperature gradient. The seasonal effects on physiological, seminal, and climatic variables were analyzed by the GLM ANOVA and CORR procedures using SAS®. The microclimatic factors were recorded in hourly intervals, and the daily mean temperature and mean relative humidity were calculated to determine the daily temperature-humidity index (THI) every day for 1 year. The temperature gradient (TG) variations of the testes were significantly higher in the autumn (4.5 °C), winter (4.0 °C), and spring (2.9 °C) compared to summer (0.9 °C) (P < 0.05). Ocular globe temperatures were lower in the winter (27.6 °C) and autumn (26.8 °C) compared to summer (33.9 °C) and spring (31.1 °C) (P < 0.05). The average MM (2.58), M (52.64), and VIG (2.70) of the semen decreased in the summer compared to other seasons (P < 0.01). The TG was negatively correlated with THI (-0.44; P < 0.05). For the seminal variables, MaD (-0.45; P < 0.05) and TD (-0.50; P < 0.01) presented a negative correlation with TG. The TG had a positive correlation between M and VIG, which had values of 0.36 and 0.35, respectively (P < 0.05). We have concluded that infrared thermography can be used to assess the testicular temperature gradient and its consequences on physical and quantitative aspects of sperm.

Phenotypic factors and genetic group on the selling price formation of beef calves sold in auctions at the Northern region of Paraná State, Brazil / Fatores fenotípicos e grupo genético na formação do preço final de bezerros de corte comercializados em leilões na região norte do Estado do Paraná, Brasil

The aim of this study is to estimate the effects of phenotypic traits on the final price of calves sold at auctions in the region of northern Paraná. Data were collected between April 2011 and April 2012 at 12 auctions, in which 197 lots were offered, totaling 4,289 animals. In this study, only the final prices charged when the deals were closed have been considered. Calves belonging to the British genetic group reached higher marketing value than zebu calves; the largest animals presented higher liquidity; buyers preferred more uniform lots, regardless of the sex of the animals.

Objetivou-se estimar os efeitos das características fenotípicas de bezerros, que podem influenciar no preço final, comercializados em leilões na região Norte do Paraná. Os dados foram coletados entre abril de 2011 e abril de 2012, em 12 leilões, em que foram ofertados 197 lotes, totalizando 4.289 animais, sendo os preços finais considerados somente nos casos de efetiva comercialização. Foi observado que os bezerros do grupo genético britânicos obtiveram valor de comercialização superior aos zebuínos; os animais de maior porte obtiveram maior liquidez; e, independente do gênero, os lotes com maior uniformidade tiveram preferência do consumidor.