Perceptions of veterinarians and producers concerning Johne’s disease prevalence and control in US beef cow-calf operations

BACKGROUND: Efforts to educate producers and veterinarians in the United States regarding the management, prevention and control of Mycobacterium avium subspecies paratuberculosis (MAP) infection have increased over recent years. While nationwide awareness about MAP infection is improving, current level of awareness among beef producers and veterinarians is largely unknown. This study compares the perceptions of beef producers and veterinarians on the burden of MAP infection in cow-calf herds and on measures to control new infections. Questionnaires were mailed to 989 US beef producers through state Designated Johne’s Coordinators and to 1080 bovine veterinarians belonging to a US nationwide professional association. RESULTS: Twenty-two percent (34/155) of producers reported having infected animals in their herds. The mean (minimum, median, maximum) prevalence reported by producers was 0.8% (0, 0, 10). Twenty-seven percent (27/100) of producers had at least one clinical animal during the previous year. Compared to the small herds (<50 head), the mean test-positive percentages and estimated prevalences were higher in medium (50–149) and highest in large (≥150) herds. Seedstock herds had a lower prevalence and these producers were more likely to enroll in Johne’s disease (JD) control programs and test their herds. Veterinarians reported a mean overall animal level prevalence in their client herds of 5% (0, 2, 60). Similarly, 26% (0, 10, 100) of client herds had at least one infected animal. Mean percentage of infected cows within infected herds was 9% (0.01, 5, 80). Producers generally performed activities to control MAP transmission more frequently than perceived by veterinarians. Compared to veterinarians’ opinions, producers were less likely to cull cows with signs consistent with JD (P < 0.01), but more likely to test purchased additions (P < 0.01). Testing recommendations by veterinarians (n = 277) for beef cow-calf herds were bacterial culture of feces (3%), PCR (14%), ELISA (35%) and a combination of these tests (47%). Seventy-nine percent of veterinarians recommended a 12-month interval between testing. CONCLUSIONS: Seedstock producers who had had JD risk assessments performed on their farms were more supportive of JD control programs and had a correspondingly lower prevalence. It is important to increase educational activities to provide relevant information to veterinarians and producers for better management and control of JD. Educational programs should target larger herds to maximize the impact

Comparison of calf weaning weight and associated economic variables between beef cows with and without serum antibodies against or isolation from feces of Mycobacterium avium subsp paratuberculosis

OBJECTIVE—To compare calf weaning weight and associated economic variables for beef cows with serum antibodies against Mycobacterium avium subsp paratuberculosis (MAP) or from which MAP was isolated from feces with those for cows that were seronegative for antibodies against or culture negative for MAP. DESIGN—Retrospective study. ANIMALS—4,842 beef cows from 3 herds enrolled in the USDA National Johne’s Disease Demonstration Herd Project. PROCEDURES—Individual cow ELISA and culture results were obtained from the project database. During each parity evaluated for each cow, the 205-day adjusted weaning weight (AWW) of its calf was calculated. The AWW was compared between test-positive and testnegative cows by use of multilevel mixed-effect models. The median value for feeder calves from 2007 to 2011 was used to estimate the economic losses associated with MAP test– positive cows. RESULTS—The AWW of calves from cows with strongly positive ELISA results was 21.48 kg (47.26 lb) less than that of calves from cows with negative ELISA results. The AWW of calves from cows classified as heavy or moderate MAP shedders was 58.51 kg (128.72 lb) and 40.81 kg (89.78 lb) less, respectively, than that of calves from MAP culture–negative cows. Associated economic losses were estimated as $57.49/calf for cows with strongly positive ELISA results and$156.60/calf and $109.23/calf for cows classified as heavy and moderate MAP shedders, respectively. CONCLUSIONS AND CLINICAL RELEVANCE—Calves from cows with MAP-positive test results had significantly lower AWWs than did calves from cows with MAP-negative test results, which translated into economic losses for MAP-infected beef herds. (J Am Vet Med Assoc 2013;243:1609–1615)http://avmajournals.avma.org/loi/javmaam2014ab201

Perceptions of veterinarians in bovine practice and producers with beef cow-calf operations enrolled in the US voluntary bovine Johne's disease control program concerning economic losses associated with Johne's disease

This study compares the perceptions of producers and veterinarians on the economicimpacts of Mycobacterium avium subspecies paratuberculosis (MAP) infection in cow-calfherds. Questionnaires were mailed to beef producers through the Designated Johne’sCoordinators and to veterinarians belonging to a nationwide professional organization.Important components of losses associated with MAP infected cows were used to estimatetotal loss per infected cow-year using an iterative approach based on collected survey data.Veterinarians were more likely to perceive a lower calving percentage in MAP infectedcows compared to producers (P = 0.02). Income lost due to the presence of Johne’s disease(JD) in an infected cattle herd was perceived to be higher by veterinarians (P < 0.01). Com-pared to veterinarians without JD certification, seedstock producers were more likely toperceive genetic losses due to culling cows positive for MAP (P < 0.01). There were mixedopinions regarding the magnitude of lowered weaning weight in calves from infected cowsand perceived differences in risk of other diseases or conditions in infected cows. An annualloss of $235 (95$89–$457) for each infected animal was estimated based on infor-mation from the producer survey. The analogous estimate using information inputs fromveterinarians was$250 ($82–$486). Mean annual loss due to JD in a 100 cow herd with a7% true prevalence was $1644 ($625–$3250) based on information provided by producers.Similarly, mean annual loss based on information collected from veterinarians was$1747($575–$3375).Program for the Study of Johne’s Disease in Texas and by a cooperative agreement with USDA-APHIS-VS.http://ww w.elsevier.com/locate/prevetmedhb2014ab201

Genome-wide association study provides insights into genes related with horn development in Nelore beef cattle.

Abstract The causal mutation for polledness in Nelore (Bos taurus indicus) breed seems to have appeared first in Brazil in 1957. The expression of the polled trait is known to be ruled by a few groups of alleles in taurine breeds; however, the genetic basis of this trait in indicine cattle is still unclear. The aim of this study was to identify genomic regions associated with the hornless trait in a commercial Nelore population. A total of 107,294 animals had phenotypes recorded and 2,238 were genotyped/imputed for 777k SNP. The weighted single-step approach for genome-wide association study (WssGWAS) was used to estimate the SNP effects and variances accounted for by 1 Mb sliding SNP windows. A centromeric region of chromosome 1 with 3.11 Mb size (BTA1: 878,631?3,987,104 bp) was found to be associated with hornless in the studied population. A total of 28 protein-coding genes are mapped in this region, including the taurine Polled locus and the IFNAR1, IFNAR2, IFNGR2, KRTAP11-1, MIS18A, OLIG1, OLIG2, and SOD1 genes, which expression can be related to the horn formation as described in literature. The functional enrichment analysis by DAVID tool revealed cytokine-cytokine receptor interaction, JAK-STAT signaling, natural killer cell mediated cytotoxicity, and osteoclast differentiation pathways as significant (P < 0.05). In addition, a runs of homozygosity (ROH) analysis identified a ROH island in polled animals with 2.47 Mb inside the region identified by WssGWAS. Polledness in Nelore cattle is associated with one region in the genome with 3.1 Mb size in chromosome 1. Several genes are harbored in this region, and they may act together in the determination of the polled/horned phenotype. Fine mapping the locus responsible for polled trait in Nelore breed and the identification of the molecular mechanisms regulating the horn growth deserve further investigation

Autozygosity islands and ROH patterns in Nellore lineages: evidence of selection for functionally important traits.

Abstract Background The aim of this study was to assess genome-wide autozygosity in a Nellore cattle population and to characterize ROH patterns and autozygosity islands that may have occurred due to selection within its lineages. It attempts also to compare estimates of inbreeding calculated from ROH (FROH), genomic relationship matrix (FGRM), and pedigree-based coefficient (FPED). Results The average number of ROH per animal was 55.15&#8201;±&#8201;13.01 with an average size of 3.24 Mb. The Nellore genome is composed mostly by a high number of shorter segments accounting for 78% of all ROH, although the proportion of the genome covered by them was relatively small. The genome autozygosity proportion indicates moderate to high inbreeding levels for classical standards, with an average value of 7.15% (178.70 Mb). The average of FPED and FROH, and their correlations (&#8722;&#8201;0.05 to 0.26) were low. Estimates of correlation between FGRM-FPED was zero, while the correlation (&#8722;&#8201;0.01 to &#8722;&#8201;0.07) between FGRM-FROH decreased as a function of ROH length, except for FROH&#8201;>&#8201;8Mb (&#8722;&#8201;0.03). Overall, inbreeding coefficients were not high for the genotyped animals. Autozygosity islands were evident across the genome (n&#8201;=&#8201;62) and their genomic location did not largely differ within lineages. Enriched terms (p&#8201;<&#8201;0.01) associated with defense response to bacteria (GO:0042742), immune complex reaction (GO:0045647), pregnancy-associated glycoproteins genes (GO:0030163), and organism growth (GO:0040014) were described within the autozygotic islands. Conclusions Low FPED-FROH correlation estimates indicate that FPED is not the most suitable method for capturing ancient inbreeding when the pedigree does not extend back many generations and FROH should be used instead. Enriched terms (p <&#8201;0.01) suggest a strong selection for immune response. Non-overlapping islands within the lineages greatly explain the mechanism underlying selection for functionally important traits in Nellore cattle

Caracterização do desequilíbrio de ligação em uma população de bovinos da raça Nelore.

Resumo: Tendo em vista a importância da estimação do desequilíbrio de ligação para a seleção genômica, o objetivo deste estudo foi estimar o desequilíbrio de ligação de uma população de bovinos da raça Nelore participantes do programa de melhoramento da ANCP. Foram utilizadas informações de 9.459 animais genotipados com um painel de alta densidade, totalizando 735.044 SNP?s, antes do controle de qualidade. A estimação do desequilíbrio de ligação foi realizada através do programa SNP1101. Os valores de LD observados para os cromossomos autossômicos variaram de 0,18 a 0,25. Para marcadores distanciados até 1 Kb a média de r² foi de 0,53 e para marcadores distanciados entre 90 e 100 Kb 0,14. Para MAF a média variou de 0,23 a 0,25, considerando MAF mínimo de 5%. Os resultados obtidos neste estudo indicam que, a densidade de marcadores utilizados foi capaz de detectar altos níveis de LD. Adicionalmente, conclui-se que marcadores distanciados até 50 Kb ainda detectam consideráveis níveis de LD. Abstract: Considering the importance of estimating linkage disequilibrium for genomic selection, the objective of this study was to estimate the linkage disequilibrium in a population of Nellore cattle participating in the ANCP breeding program. Information from 9,396 genotyped animals with a high density panel, totaling 735,044 SNP's before quality control were used. The estimation of linkage dissequilibrium (LD) was performed using the SNP1101 program. The mean LD values observed for the autosomal chromosomes ranged from 0.18 to 0.25. For markers distanced lower than 1 Kb the r² mean was 0.53, and for markers distanced between 90 and 100 Kb was 0.14. For MAF, the mean ranged from 0.23 to 0.25, a minimum MAF of 0.05 was considered. The results obtained in this study indicated that the density of markers used was able to detect high levels of LD. Additionally, for markers distanced up to 50 Kb, considerable levels of LD was detected

Microbial Fuel Cells and Microbial Ecology: Applications in Ruminant Health and Production Research

Microbial fuel cell (MFC) systems employ the catalytic activity of microbes to produce electricity from the oxidation of organic, and in some cases inorganic, substrates. MFC systems have been primarily explored for their use in bioremediation and bioenergy applications; however, these systems also offer a unique strategy for the cultivation of synergistic microbial communities. It has been hypothesized that the mechanism(s) of microbial electron transfer that enable electricity production in MFCs may be a cooperative strategy within mixed microbial consortia that is associated with, or is an alternative to, interspecies hydrogen (H2) transfer. Microbial fermentation processes and methanogenesis in ruminant animals are highly dependent on the consumption and production of H2in the rumen. Given the crucial role that H2 plays in ruminant digestion, it is desirable to understand the microbial relationships that control H2 partial pressures within the rumen; MFCs may serve as unique tools for studying this complex ecological system. Further, MFC systems offer a novel approach to studying biofilms that form under different redox conditions and may be applied to achieve a greater understanding of how microbial biofilms impact animal health. Here, we present a brief summary of the efforts made towards understanding rumen microbial ecology, microbial biofilms related to animal health, and how MFCs may be further applied in ruminant research

An updated view of hypothalamic-vascular-pituitary unit function and plasticity

The discoveries of novel functional adaptations of the hypothalamus and anterior pituitary gland for physiological regulation have transformed our understanding of their interaction. The activity of a small proportion of hypothalamic neurons can control complex hormonal signalling, which is disconnected from a simple stimulus and the subsequent hormone secretion relationship and is dependent on physiological status. The interrelationship of the terminals of hypothalamic neurons and pituitary cells with the vasculature has an important role in determining the pattern of neurohormone exposure. Cells in the pituitary gland form networks with distinct organizational motifs that are related to the duration and pattern of output, and modifications of these networks occur in different physiological states, can persist after cessation of demand and result in enhanced function. Consequently, the hypothalamus and pituitary can no longer be considered as having a simple stratified relationship: with the vasculature they form a tripartite system, which must function in concert for appropriate hypothalamic regulation of physiological processes, such as reproduction. An improved understanding of the mechanisms underlying these regulatory features has implications for current and future therapies that correct defects in hypothalamic–pituitary axes. In addition, recapitulating proper network organization will be an important challenge for regenerative stem cell treatment

TEM INVESTIGATIONS OF WC-Co ALLOYS AFTER CREEP EXPERIMENTS

Des alliages carbure de tungstène-cobalt ont été déformés par compression ou par flexion trois points dans un domaine de température 1000-1350°C et dans un domaine de contrainte 30-1000 MPa. Dans ces conditions, l'exposant des contraintes n des alliages WC-Co est fonction uniquement du pourcentage volumique en cobalt et tend vers n = 1 pour le carbure pur. L'énergie d'activation apparente est 550 kj.mole-1. Des observations en M.E.T. sur des échantillons de carbure pur déformé à 1450°C montrent une déformation intragranulaire importante. L'analyse de ces défauts a été réalisée. De plus, une étude précise a montré un comportement différent entre les joints de grains en coïncidence (Σ = 2, 4, 13a) et les joints de grains généraux. Ces analyses à l'aide des données macroscopiques permettent de proposer un modèle pour la déformation des composites carbure de tungstène-cobalt.Carbide tungsten cobalt alloys were deformed in compression or in three point bending in a temperature range 1000-1350°C and in a stress domain 30-1000MPa. In these conditions, the stress exponent n of WC-Co alloys is a function of only the cobalt volumic ratio and tends towards n = 1 for pure carbide. The apparent activation energy is 550 kj mole-1. T.E.M. investigations on pure carbide deformed at 1450°C show an extensive intragranular deformation. Analysis of these defects have been performed. Moreover an accurate study has shown a different behaviour between coincidence grain boundaries (Σ = 2, 4, 13a) and general grain boundaries. These data and macroscopic results allow to propose a model for the deformation of carbide tungsten - cobalt composites