RESUMO
Background: Cattle are susceptible to chronic leptospirosis infection, that results in reduced milk production and reproductive disorders such as abortions, stillbirths, fetal malformation, and mummified fetuses, causing significant economic losses.Commercially available vaccines against leptospirosis offer limited protection to cattle because they contain only the mostprevalent serovars worldwide, even though they are not prevalent in the specific region. This study aimed to evaluate theprevalence of specific antibodies against Leptospira serogroups, reproductive disorders and the risk factors in dairy herdsfrom different mesoregions of Rio Grande do Sul State, Southern Brazil.Materials, Methods & Results: An epidemiological survey was conducted, and serum samples from the bovine population representative of three mesoregions (MR1, MR2, and MR3) were studied; the samples were collected and tested forleptospirosis using the microscopic agglutination test (MAT) for 12 serogroups checking for the presence of agglutination.A total of 442 blood samples were collected from dairy cattle from November to December 2019 (MR1, 187; MR2, 88;and MR3, 167), including cows vaccinated with different commercial vaccines during the three months before sample collection (n = 295) and non-vaccinated against leptospirosis (n = 147). At the time of collection, an interview was conductedwith the owners with questions about the health of the animals, management, habitat, feeding and reproduction. Chi-squaretests univariate analysis with the SPSS® version 20.0 were performed to estimate the association of serogroup Djasimanseroreactivity with the occurrence of reproductive problems and related risk factors. The mean prevalence of antibodiesagainst leptospires was 78.7% (MR1, 74.9 %; MR2, 84.1 %; and MR3, 80.2 %). Serogroup prevalence was different in...
Assuntos
Animais , Bovinos , Aborto Animal/etiologia , Fatores de Risco , Leptospirose/epidemiologia , Leptospirose/etiologia , Leptospirose/veterinária , Brasil , Inquéritos Epidemiológicos/métodos , Áreas AlagadasRESUMO
The aim of this study was to evaluate effects of intra-follicular (i.f.) treatment with lipopolysaccharide (LPS) on follicular and luteal development in cows. There were 18 non-lactating cows assigned to two groups to address this aim: control group (nâ¯=â¯9), which received an i.f. injection of saline; and LPS group (nâ¯=â¯9), which received an i.f. injection of 1⯵g of LPS per mL of follicular fluid. Cows were treated with an intravaginal P4 releasing device (IVD) and estradiol benzoate on D0. On D4 and D5 cows were treated with cloprostenol sodium and on D7 the IVD was removed. At 12â¯h after IVD removal, cows were administered the i.f. injection of LPS or saline. After administration of these treatments, follicular development was evaluated every 12â¯h until ovulation. The LPS treatment increased blood flow in pre-ovulatory follicles (P = 0.05). Follicle growth was reduced by LPS injection (P < 0.02) resulting a longer period to the time of ovulation for cows in the LPS than control group (P = 0.03). The percentage of cows having ovulations was less for the LPS than control group (P = 0.03). The diameter of the CL, CL blood flow and P4 concentrations 5 and 12 days after ovulation did not differ between groups (P> 0.05). In conclusion, intra-follicular treatment with LPS resulted in a decreased rate of follicle growth, delayed timing of ovulations and a lesser number of cows having ovulations.
Assuntos
Bovinos , Lipopolissacarídeos/toxicidade , Folículo Ovariano/efeitos dos fármacos , Ovulação/efeitos dos fármacos , Animais , Feminino , Injeções , Progesterona/sangueRESUMO
The aim of this study was to evaluate the effect of exposing bovine oocytes to lipopolysaccharides (LPS) in vivo and in vitro on early embryo development. In experiment 1, cumulus oocyte complexes (COCs, n = 700/group) were challenged with 0, 0.1, 1.0 or 5.0 µg/mL of LPS during in vitro maturation (IVM). Later, in vitro fertilization (IVF) and in vitro culture (IVC) were performed. In experiment 2, COCs (n = 200/group) matured and in vitro fertilized without LPS were subjected to IVC with the same doses of LPS from experiment 1. In experiment 3, heifers received two injections of saline solution (n = 8) or 0.5 µg/kg of LPS (n = 8) 24 h apart, and 3 days later, COCs were recovered and submitted to IVM, IVF, and IVC. In experiments 1 and 3, the expression of TLR4, TNF, AREG and EREG genes in cumulus cells was evaluated. Exposure to 1 and 5 µg/mL of LPS during IVM decreased nuclear maturation (39.4 and 39.6%, respectively) compared with control (63.6%, P < 0.05). Despite that, no effect on cleavage and blastocyst rates were observed. Exposure to LPS during IVC did not affect embryonic development. In vivo exposure to LPS decreased the in vitro cleavage rate (54.3 vs 70.2%, P = 0.032), but cleaved embryos developed normally. Number of cells per embryo and gene expression were not affected by the LPS challenge in any experiment. In conclusion, although in vitro exposure to LPS did not affect early embryo development, in vivo LPS exposure reduced cleavage rate.
Assuntos
Desenvolvimento Embrionário/efeitos dos fármacos , Lipopolissacarídeos/farmacologia , Oócitos/efeitos dos fármacos , Animais , Blastocisto/citologia , Blastocisto/efeitos dos fármacos , Blastocisto/fisiologia , Bovinos , Células Cultivadas , Fase de Clivagem do Zigoto/efeitos dos fármacos , Fase de Clivagem do Zigoto/fisiologia , Células do Cúmulo/citologia , Células do Cúmulo/efeitos dos fármacos , Células do Cúmulo/fisiologia , Técnicas de Cultura Embrionária/veterinária , Embrião de Mamíferos , Feminino , Fertilização in vitro/veterinária , Regulação da Expressão Gênica/efeitos dos fármacos , Técnicas de Maturação in Vitro de Oócitos/veterinária , Oócitos/citologia , Oócitos/fisiologia , GravidezRESUMO
The aim of this study was to estimate neosporosis seroprevalence and its associated risk factors in milk herds (Bos taurus taurus) located in the northwestern region of Rio Grande do Sul State, Brazil. Three hundred twenty-two blood samples were collected from dairy cows on 18 farms in 17 cities of this region. An epidemiologic questionnaire was completed for each farm. It consisted of questions about the general characteristics of the herd, reproduction, and animal management. Serum samples were tested for Neospora caninum using a commercial enzyme-linked immunosorbent assay (ELISA) kit. Results indicated a seroprevalence of Neospora in 88.9% (16/18) of herds and 31.1% (100/322) of individuals. Risk factor analyses demonstrated that culling by reproductive disorder (OR = 0.6), flooding (OR = 0.5), and commercial sale (OR = 0.4) were associated with seroprevalence. Nevertheless, the purchase of replacement animals in the herd played an important role in disease occurrence (OR = 2.2). Results of this study suggested that Neospora caninum was present in the studied herds under investigation and that there are risk factors associated with its seroprevalence on the farms of the northwestern of Rio Grande do Sul.(AU)
O objetivo desse estudo foi estimar a soroprevalência da neosporose e os possíveis fatores de risco em rebanhos (Bos taurus taurus) localizados na mesorregião Noroeste do Rio Grande do Sul, Brasil. Foram coletadas 322 amostras de sangue de bovinos leiteiros, em 18 propriedades localizadas em 17 munícipios desta mesorregião. Um questionário epidemiológico foi aplicado em cada propriedade, contendo questões relacionadas às características gerais dos rebanhos, dados reprodutivos e manejo animal. As amostras de soro foram testadas através do teste de imunoensaio enzimático (ELISA) para Neospora caninum. Os resultados demonstraram uma soroprevalência de Neospora de 88,9% (16/18) entre os rebanhos e 31,1% (100/322) entre os indivíduos. Entre os fatores de risco analisados foi observado que descarte por problemas reprodutivos (OR=0,6), presença de áreas alagadiças (OR=0,5) e venda comercial (OR=0,4) estavam associados a soroprevalência. No entanto, a compra de animais substituídos no rebanho desempenhou um papel significativo na ocorrência da doença (OR=2,2). Os resultados desse estudo sugerem que o Neospora caninum esteve presente nos rebanhos estudados, bem como, existem fatores associados com a soroprevalência nas propriedades da mesorregião do Noroeste do Rio Grande do Sul.(AU)
Assuntos
Animais , Bovinos , Neospora/isolamento & purificação , Coccidiose/epidemiologia , Coccidiose/veterinária , Fatores de Risco , BrasilRESUMO
ABSTRACT: The aim of this study was to estimate neosporosis seroprevalence and its associated risk factors in milk herds (Bos taurus taurus) located in the northwestern region of Rio Grande do Sul State, Brazil. Three hundred twenty-two blood samples were collected from dairy cows on 18 farms in 17 cities of this region. An epidemiologic questionnaire was completed for each farm. It consisted of questions about the general characteristics of the herd, reproduction, and animal management. Serum samples were tested for Neospora caninum using a commercial enzyme-linked immunosorbent assay (ELISA) kit. Results indicated a seroprevalence of Neospora in 88.9% (16/18) of herds and 31.1% (100/322) of individuals. Risk factor analyses demonstrated that culling by reproductive disorder (OR = 0.6), flooding (OR = 0.5), and commercial sale (OR = 0.4) were associated with seroprevalence. Nevertheless, the purchase of replacement animals in the herd played an important role in disease occurrence (OR = 2.2). Results of this study suggested that Neospora caninum was present in the studied herds under investigation and that there are risk factors associated with its seroprevalence on the farms of the northwestern of Rio Grande do Sul.
RESUMO: O objetivo desse estudo foi estimar a soroprevalência da neosporose e os possíveis fatores de risco em rebanhos (Bos taurus taurus) localizados na mesorregião Noroeste do Rio Grande do Sul, Brasil. Foram coletadas 322 amostras de sangue de bovinos leiteiros, em 18 propriedades localizadas em 17 munícipios desta mesorregião. Um questionário epidemiológico foi aplicado em cada propriedade, contendo questões relacionadas às características gerais dos rebanhos, dados reprodutivos e manejo animal. As amostras de soro foram testadas através do teste de imunoensaio enzimático (ELISA) para Neospora caninum. Os resultados demonstraram uma soroprevalência de Neospora de 88,9% (16/18) entre os rebanhos e 31,1% (100/322) entre os indivíduos. Entre os fatores de risco analisados foi observado que descarte por problemas reprodutivos (OR=0,6), presença de áreas alagadiças (OR=0,5) e venda comercial (OR=0,4) estavam associados a soroprevalência. No entanto, a compra de animais substituídos no rebanho desempenhou um papel significativo na ocorrência da doença (OR=2,2). Os resultados desse estudo sugerem que o Neospora caninum esteve presente nos rebanhos estudados, bem como, existem fatores associados com a soroprevalência nas propriedades da mesorregião do Noroeste do Rio Grande do Sul.