RESUMO
This comprehensive review focuses on the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and its impact as the cause of the COVID-19 pandemic. Its objective is to provide a cohesive overview of the epidemic history and evolutionary aspects of the virus, with a particular emphasis on its emergence, global spread, and implications for public health. The review delves into the timelines and key milestones of SARS-CoV-2's epidemiological progression, shedding light on the challenges encountered during early containment efforts and subsequent waves of transmission. Understanding the evolutionary dynamics of the virus is crucial in monitoring its potential for adaptation and future outbreaks. Genetic characterization of SARS-CoV-2 is discussed, with a focus on the emergence of new variants and their implications for transmissibility, severity, and immune evasion. The review highlights the important role of genomic surveillance in tracking viral mutations linked to establishing public health interventions. By analyzing the origins, global spread, and genetic evolution of SARS-CoV-2, valuable insights can be gained for the development of effective control measures, improvement of pandemic preparedness, and addressing future emerging infectious diseases of international concern.
Assuntos
COVID-19 , SARS-CoV-2 , Humanos , SARS-CoV-2/genética , COVID-19/epidemiologia , Pandemias/prevenção & controle , Saúde Pública , Surtos de DoençasRESUMO
The growing use of visual scores (VS) and ultrasound (US) for carcass evaluation inbreeding programs, calls for a knowledge of the relationships between these traits and other relevantcharacteristics, such as feed effi ciency and production of commercial cuts. The objectiveof this study was to evaluate correlations between body visual scores and carcass traits identi-fi ed by ultrasound (US) and feed effi ciency (FE), carcass weight (HCW), dressing percentage (DP)and retail product yield (RPY) in beef cattle. Nellore cattle (male), 42 non-castrated [NCAST] and44 castrated [CAST]) were evaluated by both VS and US, at the postweaning (15-month old) andfi nishing phases (21-month old). Visual scores of conformation (C), precocity (P) and muscling(M) were assessed and the backfat thickness (UBFT), rump fat thickness (URFT) and ribeye area(UREA) were measured by ultrasound. Gain-to-feed (G:F) ratio and residual feed intake (RFI) weremeasured in feedlot. Hot carcass weight, DP and RPY were determined at harvest. Non-castratedcattle had greater HCW and RPY but lower UBFT and URFT than CAST. Postweaning VS and USwere poorly correlated with FE in both sexual conditions. Finishing VS were negatively correlatedwith G:F in CAST and fi nishing URFT was negatively correlated with RPY in NCAST. The relationshipof VS and US with feed effi ciency and meat yield is affected by age at the date of evaluationand by castration. Feed effi ciency is not related to the yield of meat cuts in Nellore cattle.
Assuntos
Animais , Bovinos , Carne Vermelha/análise , Gordura Subcutânea , Peso Corporal , Qualidade dos Alimentos , Ultrassonografia/veterináriaRESUMO
The growing use of visual scores (VS) and ultrasound (US) for carcass evaluation inbreeding programs, calls for a knowledge of the relationships between these traits and other relevantcharacteristics, such as feed effi ciency and production of commercial cuts. The objectiveof this study was to evaluate correlations between body visual scores and carcass traits identi-fi ed by ultrasound (US) and feed effi ciency (FE), carcass weight (HCW), dressing percentage (DP)and retail product yield (RPY) in beef cattle. Nellore cattle (male), 42 non-castrated [NCAST] and44 castrated [CAST]) were evaluated by both VS and US, at the postweaning (15-month old) andfi nishing phases (21-month old). Visual scores of conformation (C), precocity (P) and muscling(M) were assessed and the backfat thickness (UBFT), rump fat thickness (URFT) and ribeye area(UREA) were measured by ultrasound. Gain-to-feed (G:F) ratio and residual feed intake (RFI) weremeasured in feedlot. Hot carcass weight, DP and RPY were determined at harvest. Non-castratedcattle had greater HCW and RPY but lower UBFT and URFT than CAST. Postweaning VS and USwere poorly correlated with FE in both sexual conditions. Finishing VS were negatively correlatedwith G:F in CAST and fi nishing URFT was negatively correlated with RPY in NCAST. The relationshipof VS and US with feed effi ciency and meat yield is affected by age at the date of evaluationand by castration. Feed effi ciency is not related to the yield of meat cuts in Nellore cattle.(AU)