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Efeito do uso da inseminação artificial em tempo fixo e de sistema automático de detecção de estro na eficiência reprodutiva de rebanho leiteiro

2026-09-30T06:21:02Z

Title: Efeito do uso da inseminação artificial em tempo fixo e de sistema automático de detecção de estro na eficiência reprodutiva de rebanho leiteiro Abstract: The resumption of ovarian activity and the efficient detection of estrus during the postpartum period are critical to the reproductive performance of dairy cows. However, metabolic, productive, reproductive, and health-related factors can influence both the behavioral manifestation of estrus and the conception rate. In this context, automated activity monitoring systems have been used as auxiliary tools in reproductive management. This thesis was developed aiming to investigate factors associated with the conception rate in Girolando cows in response to fixed-time artificial insemination (TAI), as well as to evaluate the association between automated estrus detection and the resumption of ovarian activity in Holstein cows in intensive dairy production systems. In the first study, factors associated with pregnancy after artificial insemination (P/TAI) were evaluated. Moderate/Strong estrus was associated with a higher probability of P/TAI, with cows being 2.11 times more likely to become pregnant compared to those with Absent/Weak estrus (P = 0.004). Parity also influenced P/TAI: second-lactation cows were 2.89 times more likely to conceive (P = 0.003). The season was also associated with the outcome, with a lower probability of P/TAI during the Summer compared to Winter (P = 0.032). Semen type and milk production showed no significant association with P/TAI. In the second study, the occurrence of ovulation and estrus events detected by automated activity monitoring were evaluated up to 56 days into lactation. The body condition score was associated with ovarian activity, while the locomotion score was not significantly associated with ovarian activity or estrus detection. During this period, 88.9% of the cows exhibited at least one ovulation, while 80% exhibited at least one estrus event detected by the system. Silent ovulations were observed in 13.7% of the cows, and a moderate positive correlation was found between the number of ovulations and the number of detected estrus events. In conclusion, the intensity of estrus, parity, and season of the year should be considered when interpreting the reproductive performance of dairy cows in the postpartum period. In addition, automated activity monitoring is effective in helping to identify the resumption of ovarian activity, especially when an estrus alert is emitted, although it does not completely replace ultrasound evaluation given the occurrence of silent ovulations.

Epidemiologia baseada em esgoto como ferramenta de uma só saúde: vigilância do SARS-CoV-2 e da resistência antimicrobiana em Escherichia coli e Klebsiella pneumoniae.

2026-09-15T06:26:27Z

Title: Epidemiologia baseada em esgoto como ferramenta de uma só saúde: vigilância do SARS-CoV-2 e da resistência antimicrobiana em Escherichia coli e Klebsiella pneumoniae. Abstract: Wastewater-Based Epidemiology (WBE) has established itself as a strategic tool for health surveillance, enabling non-invasive pathogen monitoring and community health assessment from a One Health perspective. This thesis aimed to investigate the circulation dynamics of SARS-CoV-2 and characterize the antimicrobial resistance profile of Escherichia coli and Klebsiella pneumoniae in raw sewage in the municipality of Uberlândia-MG, Brazil. The study was divided into two surveillance axes: virological and bacterial. In the first axis, SARS-CoV-2 viral load was quantified by RT-qPCR and variants were genomically identified by sequencing at the four wastewater treatment plants of Uberlândia-MG throughout the pandemic and post-pandemic periods, correlating environmental data with clinical indicators of reported cases and deaths. The results evidenced the effectiveness of WBE as an early warning system, demonstrating concordance between viral load in effluents and the epidemiological waves of COVID- 19. In the second axis, six E. coli and three K. pneumoniae isolates recovered from the Uberabinha wastewater treatment plant were characterized for antimicrobial susceptibility and whole-genome sequence data, including sequence types, resistance genes and mutations, virulence factors and plasmid replicons; the same sewage samples were subjected to targeted enrichment metagenomics, expanding the detection of ESKAPEE taxa (Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, Enterobacter spp., and Escherichia coli) and resistance determinants not recovered by culture. The analyses revealed a high prevalence of multidrug-resistant (MDR) strains, including the detection of critical resistance mechanisms (blaCTX-M, blaKPC-2, blaNDM, blaVIM), evidencing complementarity between culture, genomic sequencing and targeted metagenomics. It is concluded that integrated raw sewage surveillance is essential for public health, providing robust data for managing viral outbreaks and controlling the spread of bacterial resistance from a One Health perspective.

Integridade cromatínica e morfometria das cabeças espermáticas e suas relações com a concepção em éguas

2026-08-25T06:22:48Z

Title: Integridade cromatínica e morfometria das cabeças espermáticas e suas relações com a concepção em éguas Abstract: The evaluation of sperm chromatin and morphometry has gained relevance for diagnosing subfertility in stallions, especially when conventional seminal parameters do not explain reproductive failures. This study investigated whether changes in chromatin compaction, detected by Toluidine Blue, Feulgen Reaction, and Acridine Orange, as well as computational sperm head morphometric variables, correlate with conception in mares inseminated with fresh or cooled semen. Additionally, sperm morphometry was compared between Quarter Horse and Mangalarga stallions in order to evaluated possible differences between breeds and whether there was a correlation with conception. Ninety-seven semen samples used for artificial insemination were analyzed, and at least 150 sperm heads per sample were examined for chromatin compaction and morphometric variables. Chromatin characteristics evaluated showed no significant correlation with conception, indicating low sensitivity of these smear methods to predict reproductive performance when ejaculates meet minimum quality standards. In contrast, morphometric variables showed a significant correlation, with the width/length ratio (r= -0,226; p= 0,0398) and ellipticity (r= 0,226; p= 0,0400) standing out, in addition to a moderate correlation for form factor (r= -0,211; p= 0,0556) and Fourier 0 (r= 0,172; p= 0,1210). Significant differences were also observed between breeds, although these did not impact conception rates. The results indicate that, while the evaluated chromatin methods are not effective predictors, computational sperm head morphometry shows potential as a complementary objective tool for estimating stallion fertility.

Avaliação otológica canina e sua relação com endocrinopatias: aspectos técnicos, micológicos e bacterianos

2026-08-25T06:20:38Z

Title: Avaliação otológica canina e sua relação com endocrinopatias: aspectos técnicos, micológicos e bacterianos Abstract: Accurate assessment of canine otological microbiota is essential for proper diagnosis and management of otitis externa, one of the most common conditions in small animal practice. This thesis investigated technical, mycological, and bacterial aspects of canine otological microbiota, with emphasis on their relationship with endocrinopathies. Eighty dogs were evaluated, including 40 with hypothyroidism or hypercortisolism and 40 healthy controls, matched by age, sex, and breed. Animals underwent complete otological evaluation including otoscopy, auricular cytology, bacterial and fungal culture. For mycological analysis, hair samples were collected by manual traction or sterile vaginal cervical brush and inoculated in DTM medium for dermatophyte identification. Quantification of Malassezia spp. was performed by cytological evaluation, and bacterial samples were identified by MALDI-TOF, subjected to antimicrobial susceptibility testing using the VITEK system, biofilm formation capacity assessment by crystal violet method followed by microbiological counting of the sessile form, and ultrastructural analysis by scanning electron microscopy. Additionally, commercial and compounded propolis-based products were tested for antibiofilm efficacy. The prevalence of Malassezia spp. was significantly higher in endocrinopathic dogs (37.5%) compared to controls (10.0%; p<0.01), with dogs with otological malasseziosis presenting a 5.4-fold higher risk of being endocrinopathic (OR = 5.40; 95% CI: 1.60-18.20). Positive fungal culture for dermatophytes was identified exclusively in endocrinopathic dogs (5.0%). Different Staphylococcus strains were isolated, with all S. pseudintermedius strains demonstrating biofilm formation capacity (BFI>1.10) and variable antimicrobial resistance profiles. Results demonstrate strong association between endocrinopathies and opportunistic fungal infections, emphasizing the importance of endocrine investigation in recurrent otitis cases, and highlight the role of bacterial biofilms in persistence of otological infections.