RESUMO
Bovine paratuberculosis causes chronic, incurable diarrhea and weight loss, resulting in decreased cattle production. The disease is caused by Mycobacterium avium subsp. paratuberculosis (MAP), an obligate intracellular mycobactin-dependent mycobacterium that replicates slowly in the host and has heightened environmental resistance. In countries where the disease is found and the damage has been quantified, direct and indirect economic losses are extremely high. Local epidemiological data is of paramount importance for the implementation of control programs. Our objective was to verify whether paratuberculosis is present in commercial dairy herds in different mesoregions of RS. Therefore, a prospective, cross-sectional and observational study was performed on dairy cattle from five mesoregions of the RS state, Brazil. Milk samples taken from individual cows on commercial farms were tested using indirect ELISA tests and classified as negative, suspicious, or positive. In herds containing at least one positive cow, we conducted convenience sampling of feces directly from the rectal ampulla to identify MAP through PCR. Of the 362 cows tested, 20 were seroreactive for paratuberculosis from two mesoregions. The PCR tests were all positive; cows with a negative ELISA and positive PCR results probably indicate that the MAP was ingested and eliminated without causing infection. We found that paratuberculosis is likely endemic in the northwest and northeast mesoregions.
A paratuberculose bovina causa diarreia crônica e incurável, perda de peso e resulta em diminuição da produção. A doença é causada pelo Mycobacterium avium subsp. paratuberculosis (MAP), micobactéria intracelular obrigatória, dependente de micobactina, que se replica lentamente no hospedeiro e possui elevada resistência ambiental. Nos países onde a doença é encontrada e os danos foram quantificados, as perdas econômicas diretas e indiretas são extremamente altas. Os dados epidemiológicos locais são de suma importância para a implementação de programas de controle. Nosso objetivo foi verificar se a paratuberculose está presente em rebanhos leiteiros comerciais em diferentes mesorregiões do RS. Para tanto, foi realizado um estudo prospectivo, transversal e observacional em bovinos leiteiros de cinco mesorregiões do estado do RS, Brasil. Amostras de leite individuais, provenientes de vacas leiteiras de fazendas comerciais foram testadas com ELISA indireto e classificadas como negativas, suspeitas ou positivas. Em rebanhos contendo pelo menos uma vaca positiva, realizamos amostragem por conveniência, em que foram coletadas fezes diretamente da ampola retal, para identificar MAP por meio da PCR. Das 362 vacas testadas, 20 foram sororreativas para paratuberculose, oriundas de duas mesorregiões. Os testes de PCR foram todos positivos. Vacas com resultado negativo no teste ELISA e PCR positivo provavelmente indicam que o MAP foi ingerido e eliminado sem causar infecção. Sugere-se que a paratuberculose é provavelmente endêmica nas mesorregiões noroeste e nordeste.
Assuntos
Animais , Feminino , Bovinos , Paratuberculose/diagnóstico , Paratuberculose/epidemiologia , Doenças dos Bovinos/microbiologia , Brasil/epidemiologia , Ensaio de Imunoadsorção Enzimática/veterinária , Reação em Cadeia da Polimerase/veterinária , Mycobacterium avium subsp. paratuberculosis/isolamento & purificação , Leite/microbiologiaRESUMO
The Japanese black cattle breed (Wagyu) has an improved metabolism, which allows them to have a higher marbling score when compared with other cattle breeds. However, this may affect other aspects of the animal's physiology, including hormone secretion and their reproductive success, such as their response to synchronization protocols and embryo production. Therefore, the objectives of this study were to test a superovulation protocol (SOV) developed with low doses of FSH and to evaluate the outcome and economic viability of embryo production using the SOV and in vitro fertilization (IVF) approaches in the Wagyu cattle breed. For that, ten Wagyu cows were submitted to five SOVs over a period of 15 months using a standard protocol: CIDR + 3 mg estradiol benzoate (D0), 35 mg FSH (Folltropin®) a.m. and p.m. (D4), 35 mg Folltropin® a.m. and 20 mg p.m. (D5), 20 mg Folltropin® a.m. and 10 mg p.m. (D6), 10 mg Folltropin® and 0.5 mg cloprostenol, both a.m. and p.m., + CIDR removal (D7), 0.05 mg GnRH + insemination 12 and 24 h after (D8) and embryo collection + 0.5 mg of cloprostenol (D16). Thirty days after each SOV, a follicular aspiration was conducted to produce IVF embryos without any pre-synchronization using standard semen in the same group of animals. The average number of embryos produced was 7.63 ± 5.61 (SOV) and 4.52 ± 2.44 (IVF) (p = 0.303). There was no significant correlation between the number of embryos produced by the different techniques (SOV and IVF), indicating that cows that respond well to SOV did not respond well to IVF and vice versa (r = 0.379, p = 0.529). The total cost of each embryo produced by SOV was R$215.00 and R$410.00 for IVF. Therefore, cows that produce less than five embryos by SOV are not economically viable due their lack of response to FSH, and the use of IVF in those animals may be more effective.
RESUMO
The Indubrasil breed was developed in the Brazilian region called Triângulo Mineiro as a result of a cross between zebu cattle. Initially, it was used as a terminal cross and currently it represents approximately 4.45% of all the Brazilian zebu cattle. Studies were conducted to estimate genetic parameters in the Indubrasil using pedigree information, however, until now, no study has been developed using large-scale genomic markers in this breed. Pedigree information are widely used to investigate population parameters; however, they can neglect some estimates when compared to the use of genomic markers. Therefore, the objective of this study was to investigate the population structure and the genetic diversity of Indubrasil cattle using a high-density Single Nucleotide Polymorphism (SNP) panel (Illumina BovineHD BeadChip 700k). Levels of genomic homozygosity were evaluated using three different approaches: Runs of homozygosity (FROH), % of homozygosis (FSNP), and inbreeding coefficient (Fx). Further, Runs of Homozygosity (ROH) segments conserved among the animals were investigated to identify possible regions associated with the breed characteristics. Our results indicate that even the Indubrasil breed having a small effective population size, the levels of homozygosity (FROH = 0.046) are still small. This was possibly caused by the cross conducted among different breeds for its development. It suggests no immediate risks associated with loss of genetic variation. This information might be used in breeding programs, for the breed conservation and for the expansion of the Indubrasil breed.