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1.
Data extracted from reports on Bos taurus × Bos indicus crossbreeding were used to estimate the amount of heterosis in these crosses. Traits studied were age at first calving, milk yield, lactation length, and calving interval. The estimates obtained were (percent of midparent means in parentheses): | Age at first calving | ?3.2 to ?4.4 months | (?8 to ?12%) | | Milk yield | 287 to 400 kg | (18 to 25%) | | Lactation length | 7 to 15 days | (2 to 5%) | | Calving interval | ?30 to ?31 days | (?7%) | 相似文献
2.
Faecal samples of 4151 dogs from Denmark, 958 dogs from Germany and 231 cats from Germany with clinical signs were examined for lungworm larvae using the Baermann funnel technique between 2003 and 2007. In total, 3.6% of Danish and German dogs shed lungworm larvae. In Denmark, patent infections of dogs with Angiostrongylus vasorum were more prevalent (2.2%) than those with Crenosoma vulpis (1.4%). In Denmark, the majority of A. vasorum- (98%) and C. vulpis-infected (80%) dogs originated from Northern Zealand. The frequency of A. vasorum and C. vulpis infections in Danish dogs obviously decreased from 2003 to 2006. In Germany, canine faecal samples were found more frequently positive for C. vulpis than for A. vasorum larvae (2.4% and 1.2%, respectively). Lungworm-infected dogs originated mainly from southern and western Germany. Larvae of Aelurostrongylus abstrusus were detected in 5.6% of cats from Germany. Overall, a distinct seasonal pattern in the detection of infected dogs was apparent for A. vasorum in Denmark and C. vulpis in Germany. The relatively high number of lungworm-infected dogs and cats indicate that these parasitic diseases should be considered in differential diagnosis of cases of treatment-resistant respiratory/cardiopulmonary distress. 相似文献
3.
The immunization procedure of DNA vaccine pcDNA–TA4–IL-2 of Eimeria tenella, including route, dose, time of immunization and age of primary immunization of chicken, was optimized. The stability and the cross-species protection of the vaccine were also analyzed. Efficacy of immunization was evaluated on the basis of oocyst decrease ratio, lesion score, body-weight gain and the anti-coccidial index (ACI). Chinese Yellow chickens were randomly distributed into corresponding groups (30/group). The challenged, unchallenged and vector control groups were designed. The results illustrated that 25 μg was the optimal dose and intramuscular injection was the most effective route to induce protective immunity. There were no significant differences of ACIs between boosting and non-boosting groups. Storage time and temperature had little effect on the immunizing efficacy of the vaccine. The vaccine could provide partial cross-protection against the challenge with E. necatrix and E. acervulina, but not with E. maxima. 相似文献
5.
The objective of this work was to describe trends in multiple-class antimicrobial resistance present in clinical isolates of Escherichia coli F4, Pasteurella multocida and Streptococcus suis from Ontario swine 1998–2010. Temporal changes in multiple-class resistance varied by the pathogens examined; significant yearly changes were apparent for the E. coli and P. multocida data. Although not present in the E. coli data, significant increases in multiple-class resistance within P. multocida isolates occurred from 2003 to 2005, coinciding with the expected increase in antimicrobials used to treat clinical signs of Porcine Circovirus Associated Disease (PCVAD) before it was confirmed. Prospective temporal scan statistics for multiple-class resistance suggest that significant clusters of increased resistance may have been found in the spring of 2004; months before the identification of the PCVAD outbreak in the fall of 2004. 相似文献
6.
Paratuberculosis, also referred to as Johne's disease, is a contagious and chronic disease in ruminants caused by Mycobacterium avium subspecies paratuberculosis (MAP) . Few estimates of the genetic variation in measures of susceptibility to MAP are available in the literature and even less have attempted to elucidate the genetic associations between measures of susceptibility to MAP and performance in dairy cattle. The objectives of this study were to estimate the genetic variation in serological response to MAP in 4789 Holstein–Friesian dairy cows from 44 Irish dairy herds, and to quantify its genetic association with performance traits measured in the first three lactations of genetically related animals. Univariate mixed linear and threshold animal models were used to estimate variance components and genetic correlations were estimated using bivariate animal linear mixed models; MAP serological response was treated as a continuous variable and dichotomous variable. The prevalence of MAP in the sample population was 4.4%. This figure cannot be extrapolated to the national dairy herd as the sample population was biased towards herds with increased likelihood of MAP infection. Estimates of heritability for MAP serological response varied from 0.07 to 0.15 depending on the model of analysis and whether serological response was treated as continuous or binary; standard errors varied from 0.024 to 0.062. Genetic correlations between MAP serological response and lactation milk, fat and protein yield were negative or close to zero although not always more than two standard errors from zero; stronger negative genetic correlations were evident in older parity animals. Serological response to MAP was not genetically correlated with milk fat concentration but was positively genetically correlated with milk protein concentration in first lactation and negatively correlated with calving interval. There was little or no genetic association between serological response to MAP and survival. Results from this study corroborate previous international suggestions that selection for reduced serological response to MAP is possible, although this does not necessarily imply a concurrent selection for either reduced prevalence of clinical disease or increased resistance to MAP infection. 相似文献
7.
Based on the natural benefits of the indigenous microbiota, lactic acid bacteria (LAB) from poultry origin were isolated from hens and broilers intestine, and their probiotic potential was further studied. The tolerance to digestion, adhesion, capture of a mannose-binding lectin, absence of virulent factors and antibiotic resistances were studied. Different in vitro and ex vivo assays were performed to select tolerant and adherent strains because standardized protocols have not been defined. Fourteen strains highly tolerant to gastrointestinal digestion were genetically identified. Hydrophobic surfaces were not required for the bacterial adhesion and only nine strains adhered ex vivo to the intestinal mucosa. Three strains captured a lectin of the same specificity of Type-1 fimbriae. Virulence factors were absent but some strains evidenced multiple antibiotic resistances. These results provide bases for a future standardization of methods for the selection of probiotic strains intended to reinforce the microbiota of newly hatched chickens. 相似文献
10.
The aim of the present study was to compare the test performances of three commercial enzyme immunoassays (EIAs) against the toxigenic culture using the cytotoxicity assay as the gold standard. All EIAs showed >78% sensitivity, and the lowest specificity was 92.6%. These results suggest that EIAs could be useful for the diagnosis of Clostridium difficile infection in foals. 相似文献
12.
Early diagnosis of MAP infection is a pressing need to enable efficient intervention with the spread of MAP infection in herds. Hence, study of lymphocyte subsets and their expressed adhesion molecules could contribute in defining a distinct diagnostic marker (or markers) at the subclinical period of the infection that could in turn facilitate the development of effective diagnostic approach. In accordance with this objective, milk and blood samples were collected from two groups of cattle naturally infected with MAP and their corresponding negative controls. Group (C) comprised 3-4 year-old ELISA negative/PCR positive-cattle that were considered as subclinical seronegative low shedder group (early stage). Group (A) included 6-8 year-old ELISA positive-cattle, which were considered as a clinical seropositive group (late stage). Flow cytometry of B cells, CD8 +, CD4 + and γδ cells and the adhesion molecules CD44 +, CD62L, LFA-1 and LPAM-1 indicated increase in CD4 + and B cells levels, with higher levels in blood than milk of group A, and significant expression of CD44 + in blood and milk and LPAM-1 in blood only. The CD8 + cells count in milk was higher than blood in the late stage. The peculiar feature of the early stage (group C) was the high level of γδ cells in the blood and milk, with tendency to express high level of CD62L. Compelling evidence could support the assumption that the dominant γδ cells at early stage of MAP infection could be of CD8CD2 −WC+1 + phenotype. γδ cells appear as promising markers in defining early changes of MAP infection due to their important role in priming innate and cell mediated immunity. Possible utilization of these peculiar changes in the γδ cells level in the early diagnosis of MAP infection should be the subject of further research. 相似文献
14.
In order to investigate the occurrence of Campylobacter, Helicobacter and Arcobacter species in caecal contents of rabbits reared in intensive and rural farms, a total of 87 samples from animals belonging to 29 farms were analysed by both cultural and PCR analyses. 相似文献
15.
Campylobacter ( C.) is one of the most common food-borne pathogen causing bacterial enteric infections in humans. Consumption of meat and meat products that have been contaminated with Campylobacter are the major source of infection. Pigs are a natural reservoir of Campylobacter spp. with C. coli as the dominant species. Even though some studies focussed on transmission of C. coli in pig herds and the excretion in faeces, little is known about the colonisation and excretion dynamics of C. coli in a complex gut microbiota present in weaned piglets and the translocation to different tissues. 相似文献
16.
The present study on defined double deletion (Δ aroAΔ htrA) mutant (S30) of Salmonella enterica serovar Abortusequi evaluated it for safety, immunogenicity, and efficacy as a vaccine candidate in equids. The candidate strain was found safe in equids (foals, male and female horses and donkeys, and pregnant and nonpregnant mares) and induced good humoral and cell-mediated immunity on administration through oral route. The strain was not excreted in feces of vaccinated animals. The vaccine candidate administered orally (1 × 10 11 cfu per animal) protected mares even after 180 days of inoculation against abortion on challenge with wild-type S. Abortusequi strain whereas in nonvaccinated control, all mares aborted. The vaccination in infertile mares resulted in regaining of fertility in 67%–80% thoroughbred mares at two different breeding farms. Further, the humoral immunity was transferred to foals from vaccinated mothers through colostrum, but no placental transfer was evident. Thus, the vaccine under study may be recommended for use in equids to control S. Abortusequi infection–associated abortions and also to enhance fertility of temporarily infertile mares in endemic areas. 相似文献
17.
A study was carried out to assess the efficacy and the economic profit of prophylactic treatment against Isopsora suis with toltrazuril or with a sulfamethazine/trimethoprim combination in piglets from an intensive pig farm. Thirty-one litters were included in study. Eight litters were treated once with toltrazuril (20 mg/kg b.w.) at 3 days of age (Toltra group); 8 litters were treated with the sulphonamide combination (sodium sulfamethazine 35 mg and trimethoprim 7 mg/kg b.w.) for 3 consecutive days starting at 3 days of age (Sulfa group), and 15 litters were untreated (control group). Counts of oocyst per gram on pooled feces sampled from each litter were carried out on Days 7, 14, 21 and 28 and diarrhea was registered daily from pooled samples. Piglets were weighed on Days 1, 7 and 28 and mean weight gain (WG) and daily weight gain (DWG) were evaluated. The economic profit of treatment was evaluated comparing the WG of piglets of each treatment group from the day of birth to Day 28. On Days 14, 21 and 28, toltrazuril showed a better efficacy in controlling fecal oocyst output, diarrhea and weight gain compared with sulphamidic treatment ( P < 0.001). The budgeting analysis showed a return of economic benefit of € 0.915 per toltrazuril-treated piglets and an additional cost of € 1.155 per sulphonamide-treated piglets. 相似文献
19.
Antibiotic resistance and ESBL constitute a risk to human and animal health. Birds residing close to humans could mirror the spectrum of human associated antibiotic resistance. Household pigeons were screened in Bangladesh to shed light on human associated, as well as, environmental antibiotic resistance. Escherichia coli from pigeons ( n = 150) were tested against 11 antibiotics. 89% E. coli isolates were resistant to one or more critically important human antibiotics like ampicillin, cefadroxil, mecillinam, ciprofloxacin, gentamicin and tigecycline. No carbapenamase-producers were detected and the lower ESBL prevalence (5%) in pigeons. ESBL-producing E. coli isolates had blaCTX-M-15 genes. Pigeons shared some bacterial clones and had bird associated sequence types like E. coli ST1408. Fecal carriage of bacteria resistance of critically important human antibiotics, together with examples of shared genotypes among pigeons, indicate the human-birds and bird to bird transmissions are important in the epidemiology of antibiotic resistance. 相似文献
20.
Only limited information is available on the epidemiology and pathogenesis of Bovine Herpesvirus 1 (BoHV-1) in domestic buffalos. In this study, a virulent BoHV-1 field strain isolated from cattle was inoculated into buffaloes to evaluate their susceptibility to the virus and to investigate the establishment of viral latency through clinical, virological and serological investigations. Latency was also studied by attempting viral reactivation using pharmacological induction. Six of seven male, 5 months old buffaloes were intranasally inoculated with BoHV-1; the other animal was kept as negative control. The animals were clinically monitored during the post-infection (P.I.) and the post-pharmacological induction (P.P.) periods. During these periods, nasal and rectal swabs, and blood samples, with and without anticoagulant, were collected at 2–3 day intervals. On culling the animals, 206 days P.I., their trigeminal ganglia and tonsils were collected. No clinical signs referable to BoHV-1 were observed throughout the experimental period. However, seropositivity was detected in all infected animals within day 20 P.I., using BoHV-1 glycoprotein E and glycoprotein B competitive ELISAs (IDEXX) and virus neutralisation test. In real-time PCR (RT-PCR), five of these animals were positive, at least once, for nasal or rectal swabs, during the P.I. period. The sixth infected animal was found positive only in the trigeminal ganglia after culling. Ganglia were also positive for two other animals. Virus isolation in permissive cell-lines was successful for a part of the RT-PCR positive samples. The detected viruses were confirmed by genetic analysis as identical to the inoculated strain. No evidence of infection was observed in the negative control. This study represents the first experimental transmission of BoHV-1 in buffaloes, confirming their susceptibility to infection and their possible role as host/reservoirs of BoHV-1. 相似文献
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