Ticks are able to transmit tick-borne infectious agents to vertebrate hosts which cause major constraints to public and livestock health. The costs associated with mortality, relapse, treatments, and decreased production yields are economically significant. Ticks adapted to a hematophagous existence after the vertebrate hemostatic system evolved into a multi-layered defense system against foreign invasion (pathogens and ectoparasites), blood loss, and immune responses. Subsequently, ticks evolved by developing an ability to suppress the vertebrate host immune system with a devastating impact particularly for exotic and crossbred cattle. Host genetics defines the immune responsiveness against ticks and tick-borne pathogens. To gain an insight into the naturally acquired resistant and susceptible cattle breed against ticks, studies have been conducted comparing the incidence of tick infestation on bovine hosts from divergent genetic backgrounds. It is well-documented that purebred and crossbred Bos taurus indicus cattle are more resistant to ticks and tick-borne pathogens compared to purebred European Bos taurus taurus cattle. Genetic studies identifying Quantitative Trait Loci markers using microsatellites and SNPs have been inconsistent with very low percentages relating phenotypic variation with tick infestation. Several skin gene expression and immunological studies have been undertaken using different breeds, different samples (peripheral blood, skin with tick feeding), infestation protocols and geographic environments. Susceptible breeds were commonly found to be associated with the increased expression of toll like receptors, MHC Class II, calcium binding proteins, and complement factors with an increased presence of neutrophils in the skin following tick feeding. Resistant breeds had higher levels of T cells present in the skin prior to tick infestation and thus seem to respond to ticks more efficiently. The skin of resistant breeds also contained higher numbers of eosinophils, mast cells and basophils with up-regulated proteases, cathepsins, keratins, collagens and extracellular matrix proteins in response to feeding ticks. Here we review immunological and molecular determinants that explore the cattle tick Rhipicephalus microplus-host resistance phenomenon as well as contemplating new insights and future directions to study tick resistance and susceptibility, in order to facilitate interventions for tick control.

BackgroundTicks cause massive damage to livestock and vaccines are one sustainable substitute for the acaricides currently heavily used to control infestations. To guide antigen discovery for a vaccine that targets the gamut of parasitic strategies mediated by tick saliva and enables immunological memory, we exploited a transcriptome constructed from salivary glands from all stages of Rhipicephalus microplus ticks feeding on genetically tick-resistant and susceptible bovines.ResultsDifferent levels of host anti-tick immunity affected gene expression in tick salivary glands; we thus selected four proteins encoded by genes weakly expressed in ticks attempting to feed on resistant hosts or otherwise abundantly expressed in ticks fed on susceptible hosts; these sialoproteins mediate four functions of parasitism deployed by male ticks and that do not induce antibodies in naturally infected, susceptible bovines. We then evaluated in tick-susceptible heifers an alum-adjuvanted vaccine formulated with recombinant proteins. Parasite performance (i.e. weight and numbers of females finishing their parasitic cycle) and titres of antigen-specific antibodies were significantly reduced or increased, respectively, in vaccinated versus control heifers, conferring an efficacy of 73.2%; two of the antigens were strong immunogens, rich in predicted T-cell epitopes and challenge infestations boosted antibody responses against them.ConclusionMining sialotranscriptomes guided by the immunity of tick-resistant hosts selected important targets and infestations boosted immune memory against salivary antigens.Electronic supplementary materialThe online version of this article (doi:10.1186/s13071-017-2136-2) contains supplementary material, which is available to authorized users.

Bovine hemoplasmas are bacteria found on the erythrocyte surface or free in the plasma of cattle. The aim of the present study was to evaluate the occurrence of 'Candidatus Mycoplasma haemobos' ('C. M. haemobos') in Holstein and Jersey cattle raised in Londrina and surroundings, northern region of the State of Parana, Southern Brazil. PCR testing directed to 16S rRNA gene fragment was performed to investigate the occurrence and characterize the molecular identity of 'C. M. haemobos'. A total of 264/433 (60.97%) blood samples were positive by PCR. Further alignment of 500-bp amplicons to available sequences at the GenBank database showed high identity (100%) to 'C. M. haemobos'. To the author's knowledge, this is the first molecular confirmation of the hemoplasma 'C. M. haemobos' in cattle from Brazil. Moreover, 'C. M. haemobos' was observed in high occurrence in dairy cattle, and may have significant impact in livestock production.

Bovine cysticercosis is a disease that is endemic in several countries with an important zoonotic potential but with an increasing public health concern. The meat inspection at slaughterhouses is fundamental to establish the prevalence and prevention of zoonotic diseases, such as cysticercosis. However, in Brazil, there is no study investigating the dynamics of cysticercosis in slaughtered cattle from the entire country. Thus, the aim was to use Geographic Information System (GIS) as a tool to analyze the prevalence of bovine cysticercosis in slaughtered cattle, by using the data from slaughterhouses inspected by the Federal Inspection Service of the Ministry of Agriculture, Livestock and Supply (SIF/MAPA), during January/2007 to April/2010. Data from slaughtered cattle was used to generate a bovine cysticercosis database for all states and municipalities of Brazil, in order to analyze and create epidemiological maps using the GIS software. During the period analyzed, 75.983.590 cattle were slaughtered and the prevalence of bovine cysticercosis in Brazil was 1.05%, with the Southeast region presenting the majority of cases. The highest amount of bovine cysticercosis cases occurred in the state of São Paulo (400,834) followed by Mato Grosso do Sul (151,735), and Paraná (94,046), while there was no observation of occurrence in nine states. The data provided by slaughterhouses inspected by The SIF/ MAPA can be used as an informative source for animal and public health agencies for the prevention of the taeniasis/cysticercosis complex. This study elucidates the importance of meat inspection associated with epidemiological maps, targeting the disease control in livestock and the active surveillance for potential zoonotic human infection. Data from this study suggest bovine cysticercosis is endemic in several Brazilian states, and the risk of infection is directly related with the principal areas of commercial cattle rearing, irrespective of the demographics of the human population. ResumoCisticercose bovina é uma doença endêmica em vários países com um importante potencial zoonótico e uma crescente importância na saúde pública. A inspecção da carne nos matadouros é fundamental para estabelecer a prevalência e prevenção de doenças zoonóticas, tais como a cisticercose. No entanto, no Brasil, não há estudo que tenha investigado a dinâmica da cisticercose em bovinos abatidos em todo o país. Assim, o presente estudo teve como objetivo usar Sistema de Informação Geográfica (GIS) como uma ferramenta para analisar a prevalência de cisticercose bovina em bovinos, usando os dados de matadouros inspecionados pelo Serviço de Inspeção Federal do Ministério da Agricultura, Pecuária e Abastecimento (SIF/MAPA), no período de janeiro de 2007 a abril de 2010. As informações de bovinos abatidos foram usadas para gerar um banco de dados sobre cisticercose bovina para todos os estados e municípios do Brasil, a fim de analisar e criar mapas epidemiológicos usando o software GIS. Durante o período analisado, 75.983.590 bovinos for...

The antral follicle count (AFC) represents the number of follicles visualized by ultrasonography in the ovaries. Antral follicle count tends to be variable among cows but with high repeatability within the same individual. In the last decade, AFC has been considered a biological marker of fertility with many positive aspects of reproductive efficiency for those animals with high AFC. For instance, a larger number and better-quality embryos, better pregnancy rates, increased concentrations of circulating progesterone, in addition to other characteristics linked to fertility, are all responses observed in individuals with high compared with those with low AFC in Bos taurus cattle. However, the positive association between AFC and fertility did not follow the same pattern for Bos indicus. Recent articles showed no connection between fertility and number of antral follicles or better reproductive efficiency for high AFC group in Zebu cows. Thus, the aim of this review is to discuss the various data concerning AFC between indicus and taurus cattle. Additionally, we consider AFC to be a possible tool to improve cattle performance in reproductive biotechnology.

Oocyte mitochondria are increased in number, smaller, and rounder in appearance than mitochondria in somatic cells. Moreover, mitochondrial numbers and activity are narrowly tied with oocyte quality because of the key role of mitochondria to oocyte maturation. During oocyte maturation, mitochondria display great mobility and cluster at specific sites to meet the high energy demand. Conversely, oocyte mitochondria are not required during early oogenesis as coupling with granulosa cells is sufficient to support gamete's needs. In part, this might be explained by the importance of protecting mitochondria from oxidative damage that result in mutations in mitochondrial DNA (mtDNA). Considering mitochondria are transmitted exclusively by the mother, oocytes with mtDNA mutations may lead to diseases in offspring. Thus, to counterbalance mutation expansion, the oocyte has developed specific mechanisms to filter out deleterious mtDNA molecules. Herein, we discuss the role of mitochondria on oocyte developmental potential and recent evidence supporting a purifying filter against deleterious mtDNA mutations in oocytes.

Mitochondrial function, largely regulated by the dynamics of this organelle, is inextricably linked to the oocyte health. In comparison with most somatic cells, mitochondria in oocytes are smaller and rounder in appearance, suggesting limited fusion. The functional implications of this distinct morphology, and how changes in the mitochondrial shape translate to mitochondrial function in oogenesis is little understood. We, therefore, asked whether the pro‐fusion proteins mitofusins 1 (MFN1) and 2 (MFN2) are required for the oocyte development. Here we show that oocyte‐specific deletion of Mfn1, but not Mfn2, prevents the oocyte growth and ovulation due to a block in folliculogenesis. We pinpoint the loss of oocyte growth and ovulation to impaired PI3K‐Akt signaling and disrupted oocyte‐somatic cell communication. In support, the double loss of Mfn1 and Mfn2 partially rescues the impaired PI3K‐Akt signaling and defects in oocyte development secondary to the single loss of Mfn1. Together, this work demonstrates that the mitochondrial function influences the cellular signaling during the oocyte development, and highlights the importance of distinct, nonredundant roles of MFN1 and MFN2 in oogenesis.

The number of embryos produced by in vitro fertilization (IVF) has grown exponentially in recent years. Recently, for the first time, the number of embryos produced and transferred in vitro was significantly higher than the number developed in vivo worldwide. In this context, a particular boost occurred with ovum pick-up (OPU) and in vitro embryos produced in North America, and this technology is becoming more prominent for commercial dairy farms. However, despite many advances in recent decades, laboratories and companies are looking for methods and alternatives that can be used in collaboration with the existing process to improve it. Among the strategies used to improve the dairy industry are the use of genomic analysis for the selection of animals with desired traits or as an evaluation tool of oocyte and embryo quality, the optimization of the collection and use of gametes from prepubertal females and males, the effective use of sexed semen, and improvements in culture media and methods of embryo cryopreservation. Thus, this review aims to discuss the highlights of the commercial use of IVF and some strategies to increase the application of this technique in large-scale dairy programs.