Animals inheriting the slick hair gene have a short, sleek, and sometimes glossy coat. The objective of the present study was to determine whether slick-haired Holstein cows regulate body temperature more effectively than wild-type Holstein cows when exposed to an acute increase in heat stress. Lactating slick cows (n = 10) and wild-type cows (n = 10) were placed for 10 h in an indoor environment with a solid roof, fans, and evaporative cooling or in an outdoor environment with shade cloth and no fans or evaporative cooling. Cows were exposed to both environments in a single reversal design. Vaginal temperature, respiration rate, surface temperature, and sweating rate were measured at 1200, 1500, 1800, and 2100 h (replicate 1) or 1200 and 1500 h (replicate 2), and blood samples were collected for plasma cortisol concentration. Cows in the outdoor environment had higher vaginal and surface temperatures, respiration rates, and sweating rates than cows in the indoor environment. In both environments, slick-haired cows had lower vaginal temperatures (indoor: 39.0 vs. 39.4 degrees C; outdoor 39.6 vs. 40.2 degrees C; SEM = 0.07) and respiration rate (indoor: 67 vs. 79 breaths/ min; outdoor 97 vs. 107 breaths/min; SEM = 5.5) than wild-type cows and greater sweating rates in unclipped areas of skin (indoor: 57 vs. 43 g x h(-1)/m(2); outdoor 82 vs. 61 g x h(-1)/m(2); SEM = 8). Clipping the hair at the site of sweating measurement eliminated the difference between slick-haired and wild-type cows. Results indicate that slick-haired Holstein cows can regulate body temperature more effectively than wild-type cows during heat stress. One reason slick-haired animals are better able to regulate body temperature is increased sweating rate.
Menadione is a naphthoquinone used as a vitamin K source in animal feed that can generate reactive oxygen species (ROS) and cause apoptosis. Here, we examined whether menadione reduces development of preimplantation bovine embryos in a ROS-dependent process and tested the hypothesis that actions of menadione would be reduced by insulin-like growth factor-1 (IGF-1). Menadione caused a concentration-dependent decrease in the proportion of embryos that became blastocysts. All concentrations tested (1, 2.5, and 5.0 microM) inhibited development. Treatment with 100 ng/ml IGF-1 reduced the magnitude of the anti-developmental effects of the two lowest menadione concentrations. Menadione also caused a concentration-dependent increase in the percent of cells positive for the TUNEL reaction. The response was lower for IGF-1-treated embryos. The effects of menadione were mediated by ROS because (1) the anti-developmental effect of menadione was blocked by the antioxidants dithiothreitol and Trolox and (2) menadione caused an increase in ROS generation. Treatment with IGF-1 did not reduce ROS formation in menadione-treated embryos. In conclusion, concentrations of menadione as low as 1.0 muM can compromise development of bovine preimplantation embryos to the blastocyst stage of development in a ROS-dependent mechanism. Anti-developmental actions of menadione can be blocked by IGF-1 through effects downstream of ROS generation.
We compared diurnal patterns of vaginal temperature in lactating cows under grazing conditions to evaluate genotype effects on body temperature regulation. Genotypes evaluated were Holstein, Jersey, Jersey x Holstein and Swedish Red x Holstein. The comparison of Holstein and Jersey versus Jersey x Holstein provided a test of whether heterosis effects body temperature regulation. Cows were fitted with intravaginal temperature recording devices that measured vaginal temperature every 15 min for 7 days. Vaginal temperature was affected by time of day (P < 0.0001) and genotype x time (P < 0.0001) regardless of whether days in milk and milk yield were used as covariates. Additional analyses indicated that the Swedish Red x Holstein had a different pattern of vaginal temperatures than the other three genotypes (Swedish Red x Holstein vs others x time; P < 0.0001) and that Holstein and Jersey had a different pattern than Jersey x Holstein [(Holstein + Jersey vs Jersey x Holstein) x time, P < 0.0001]. However, Holstein had a similar pattern to Jersey [(Holstein vs Jersey) x time, P > 0.10]. These genotype x time interactions reflect two effects. First, Swedish Red x Holstein had higher vaginal temperatures than the other genotypes in the late morning and afternoon but not after the evening milking. Secondly, Jersey x Holstein had lower vaginal temperatures than other genotypes in the late morning and afternoon and again in the late night and early morning. Results point out that there are effects of specific genotypes and evidence for heterosis on regulation of body temperature of lactating cows maintained under grazing conditions and suggest that genetic improvement for thermotolerance through breed choice or genetic selection is possible.
Follicular estradiol triggers luteolysis in cattle. Therefore, the control of follicle growth and steroidogenesis is expected to modulate luteal function and might be used as an anti-luteolytic strategy to improve embryo survival. Objectives were to evaluate follicular dynamics, plasma concentrations of estradiol and luteal lifespan in Bos indicus and crossbred cows subjected to sequential follicular aspirations. From D13 to D25 of a synchronized cycle (ovulation = D1), Nelore or crossbred, non-pregnant and non-lactating cows were submitted to daily ultrasound-guided aspiration of follicles >6 mm (n = 10) or to sham aspirations (n = 8). Diameter of the largest follicle on the day of luteolysis (7.4 ± 1.0 vs 9.7 ± 1.0 mm; mean ± SEM), number of days in which follicles >6 mm were present (2.3 ± 0.4 vs 4.6 ± 0.5 days) and daily mean diameter of the largest follicle between D15 and D19 (6.4 ± 0.2 vs 8.5 ± 0.3 mm) were smaller (p < 0.01) in the aspirated group compared with the control group, respectively. Aspiration tended to reduce (p < 0.10) plasma estradiol concentrations between D18 and D20 (2.95 ± 0.54 vs 4.30 ± 0.55 pg/ml). The luteal lifespan was similar (p > 0.10) between the groups (19.6 ± 0.4 days), whereas the oestrous cycle was longer (p < 0.01) in the aspirated group (31.4 ± 1.2 vs 21.2 ± 1.3 days). Hyperechogenic structures were present at the sites of aspiration and were associated with increase in concentration of progesterone between luteolysis and oestrus. It is concluded that follicular aspiration extended the oestrous cycle and decreased the average follicular diameter on the peri-luteolysis period but failed to delay luteolysis.
ResumoDurante o período crítico do reconhecimento materno, compreendido entre o 15º e 19º dias da gestação, o concepto deve sintetizar competentemente moléculas capazes de bloquear a síntese de prostaglandina F2α (PGF2α) e a luteólise. Em bovinos, a principal macromolécula protéica envolvida em tal bloqueio é o interferon-tau (IFN-τ). Durante o período crítico, falhas neste reconhecimento determinam à mortalidade embrionária em até 40% das fêmeas inseminadas. Informações sobre o IFN-τ em animais Bos taurus indicus, ainda são restritas. Este estudo objetivou uma avaliação quantitativa do IFN-τ durante o período crítico do reconhecimento materno, em lavados uterinos obtidos por sonda de Foley (dias 14, 16 e 18 pós-estro) ou post-mortem (dia 18 pós-estro). Para tanto, foram utilizadas fêmeas multíparas azebuadas (Bos taurus indicus), cíclicas ou prenhes, nos dias 14, 16 e 18 pós-estro. Para a obtenção dos lavados, os úteros foram infundidos com solução de Ringer Simples. Os lavados foram concentrados por ultra-filtração e liofilizados. As macromoléculas protéicas foram separadas por Eletroforese Unidimensional SDS-PAGE, em gel com 15% de poliacrilamida. A quantificação do IFN-τ nos lavados uterinos foi realizada por Western-Blotting e densitometria. Tanto nos lavados obtidos por sonda de Foley quanto nos post-mortem foi possível observar bandas de proteínas que apresentaram reação cruzada com os anticorpos utilizados no WesternBlotting. O IFN-τ foi detectado apenas nos lavados uterinos post-mortem de vacas prenhes (P<0,05). A densidade óptica não foi afetada pelo dia do período crítico, estado (cíclico ou prenhe) ou interação dia x estado. Nos lavados post-mortem não houve efeito de peso do concepto ou concentração de progesterona plasmática no dia do lavado na densidade da banda protéica referente ao IFN-τ . Concluiu-se que a detecção e quantificação do IFN-τ no ambiente uterino de vacas azebuadas, nestas condições experimentais, é possível apenas em lavados uterinos obtidos post-mortem.
In the context of Industry 5.0, collaborative automation and decision support through ubiquitous digital processing provide a privileged ap-proach to examining the human factor in the industry. At the same time, new technologies that have been under development since the in-ception of Industry 4.0, such as IoT devices, artificial vision systems, image processing algorithms, artificial intelligence, and others, have brought important opportunities to the industry, which has historically based its process transformation and management on a preventive ap-proach that helps improving decision-making. Musculoskeletal disor-ders in industrial working scenarios are often associated with the accu-mulation of stress over time, which can impact the muscles, tendons, ligaments, joints, and other parts of the body. To prevent injuries and complications in the short, medium, or long term, Cyber-Physical-Human Systems (CPHS) can be adopted to correct risky actions of op-erators in real-time. This work presents preliminary results regarding the study, understanding, and identification of operator postures in the heavy metalworking industry. The study was based on the comparison of the commonly used methods for ergonomic posture and movement assessment. The adopted approach takes advantage of computer vi-sion for operator pose identification and tracking to effectively detect the most frequently repeating body postures. The most repeated pos-tures are then categorized according to their ergonomic compatibility. To evaluate the proposed approach, a dataset has been acquired based on the observation of real operator actions. Based on the results, the implemented system enables us to actively evaluate the appropriate-ness of workers' postures in real-time.
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