Bovine brucellosis (BB) is a compulsory notifiable bacterial disease caused by Brucella abortus, which is responsible for severe reproductive disorders in cattle, considerable damages to trade and public health damage. The objectives of this study were to identify the frequency of BB and to analyze the risk factors in the dairy herds of the Rio Branco microregion, in the state of Acre, Brazil. Thus, 527-bovine-serological samples were submitted to the buffered acidified antigen test and to 2-mercaptoethanol. Risk factors were characterized by the administration of epidemiological questionnaires. The logistic regression test was used to evaluate the existence of a significant association between the variables. The frequency of BB in the Rio Branco microregion was 10.6% (56/527). The inappropriate destination of the aborted fetus and placental remnants (odds ratio — OR = 13.6), the slaughter of cattle within the property (OR = 3.4) and the age range above 4 years old (OR = 2.9) were the most significant risk factors identified by the logistic regression model. According to the results of this study, it is recommended to intensify BB control and prophylaxis measures in the microregion of Rio Branco, especially those related to sanitary and reproductive management in the livestock breeding.

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Introduction: Escherichia coli strains that lead to enteritis are considered an important cause of diarrhea in calves. For correct identification, these microorganisms must be differentiated from non-pathogenic members of the intestinal microbiota. The aim of the present work was to characterize E. coli isolates in calves regarding the presence of virulence genes that cause enteritis and evaluate the sensitivity of the isolates to different antimicrobials. Methodology: One hundred forty-nine samples from beef cattle and 27 samples from dairy cattle were evaluated. All samples were submitted to microbiological identification and the disk diffusion antibiogram test. The polymerase chain reaction method was used to detect virulence genes. Results: A hundred seventy-six samples were biochemically identified as E. coli and antibiograms were determined. The samples were then submitted to PCR; 35 were positive for the eae gene (19.88%), 135 (76.70%) for the stx1 gene, 62 (35.22%) for the stx2 gene, 159 (90.34%) for the sta gene and 35 (19.88%) for the ltII gene. No samples were positive for the cnf gene. Based on these results, the E. coli isolates were classified into pathotypes: enteropathogenic (n = 3), enterohemorrhagic (n = 32), Shiga toxin-producing (n = 122) and enterotoxigenic (n = 163). The antimicrobial sensitivity tests revealed that 77.2% of the isolates were resistant to three or more pharmacological groups, characterizing these isolates as multidrug resistant. Conclusions: Enterotoxigenic E. coli was the predominant pathotype. Moreover, the prevalence of multidrug-resistant isolates was very high, accounting for the vast majority of isolates.

Background: Enzootic bovine leukosis (EBL) is a viral and lymphoproliferative disease that attributes negative economic impacts to dairy farming. The immunosuppressive condition of these bovines favors the development of bacterial diseases such as tuberculosis, brucellosis, and bovine leptospirosis, which implications to the public health given that they are zoonosis. Diagnosis and control of EBL are neglected in cattle rearing, allowing their dissemination, especially in developing countries. In this sense, the objective of this study was to analyze the risk factors of EBL in dairy cattle from the Brazilian Amazon. Materials, Methods & Results:In order to identify the BLV-infected animals (527 serological samples), we used the agarose gel immunodiffusion serological test (IDGA) to diagnose the EBL and characterize the risk factors through the application of epidemiological questionnaires. We used the logistic regression test to evaluate the existence of a significant association between the variables. The EBL frequency in the study area was 14.42%. We detected seroreagent bovines in all municipalities evaluated with 95% of the properties showing outbreaks of the disease. The reuse of needles was the risk factor with the most significant statistical association (P < 0.01; OR = 2.16). Discussion: The origin of EBL in the Brazilian Amazon is probably related to the expansion of dairy cattle in the 1980s, which, at first, demanded the importation of cattle for the fast formation of the herds, without complying with the sanitary criteria of animal commercialization. The frequency of EBL in the Rio Branco microregion is below the estimated national average, as well as the regional level. The reduced influx of animals due to the geographical situation of Acre, since it is an area of greater physical isolation due to forest and river barriers, may influence the observed frequency. Different environmental conditions, herd size, cattle management, genetics and particularities of the diagnostic techniques should also be considered. The Rio Branco microregion can currently be considered as an area of medium frequency for BLV infection, a situation that ranges from 11 to 30% in the occurrence rate. When compared to herds with low infection frequency (<10%), the elimination of seroreagent animals and their respective outbreaks become more expensive in areas of medium or high frequency. As for the number of outbreaks detected, the finding reflects the degree of negligence regarding the prophylactic measures of EBL since it is a silent propagation disease, as well as the implications for the absence of official control and eradication programs in Brazil. According to the final logistic regression model, the reuse of needles for vaccinations, deworming, and for applying other drugs in different animals was the risk factor of greater association in the region, explaining the widespread occurrence of EBL in the studied farms. In Canadian herds, this practice also was associated with an increase in clinical cases. It is known that ...

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Gastrointestinal nematodes (GINs) in beef calves in the preweaning period can be an underestimated problem, and an adequate control program can result in increased productivity. In the current scenario of anthelmintic resistance, clinical studies with highly effective molecules with a prolonged period of action can contribute to the development of technologies applied in the field. The objective of this study was to evaluate the effects of a 10% moxidectin formulation (10%MOX), administered to calves aged 4–5 months, in the control of gastrointestinal nematodes and weight gain until the time of weaning. The study was divided into 2 stages. The first stage was carried out on a farm, with a randomized block design based on fecal egg counts (FEC), live weight, number of calvings of the mother, breed of the calves, and pickets. In the second stage, the study was repeated on 10 other farms, following a completely randomized design, to confirm the results obtained in the first stage. In all experiments there was a treated group and a placebo group. In the first stage, the effectiveness of 10%MOX in the FECRT performed on the 38th day post-treatment was 98.49%, and the treated animals still had lower FEC averages and a 9.4 kg increase in weight at weaning compared to those from the placebo group. In the second stage, the average increase in weight gain was 6.1 kg, confirming the results of the first stage. The study demonstrated effective control of GINs and improvement in the productive performance of calves treated in the preweaning phase, using 10% moxidectin.

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