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1.
In each of 42 Danish dairy herds, ten young stock aged 8–18 months were tested for antibodies against bovine virus diarrhoea virus (BVDV). At the same time a bulk milk sample from each herd was examined for antibodies against BVDV.

The herds could be divided into two distinct groups: (1) Group A (24 herds) had three or less antibody carriers among the ten young stock sampled from each herd and were considered ‘slightly infected’; (2) Group B (18 herds) had eight or more antibody carriers in the ‘spot’ sample and were therefore considered ‘heavily infected’. Persistently infected animals were not found in two Group A herds studied by a subsequent total herd blood test but were detected in five Group B herds in which all animals in the herds were subsequently tested.

Bulk milk titers were generally higher in Group B than in Group A herds. However, there was considerable variation, and in most cases it was not possible to distinguish the two herd categories from one another by means of bulk milk titers.  相似文献   


2.
Conjoint analysis is a technique well known in marketing research to elicit consumer preferences and opinions. This paper describes the results of an experiment which explores the potential application of conjoint analysis in the field of veterinary epidemiology and economics. In this experiment, the method of conjoint analysis was used to elicit the opinion of experts about the relative importance of risk factors concerning contagious animal diseases. Diseases studied were: African Swine Fever (ASF), Classical Swine Fever (CSF), Foot-and-Mouth Disease (FMD), Swine Vesicular Disease (SVD), Newcastle Disease (NCD) and Avian Influenza (AI). Risk factors included were import of livestock, import of animal products, feeding of swill, tourists, returning livestock trucks and air. The conjoint analysis technique was used to draw up a questionnaire which was handed out during the 7th ISVEE held at Nairobi, Kenya, from 15 to 19 August 1994. According to the experts approached, the factors ‘import of livestock’ and ‘import of animal products’ were the major sources of risk for all diseases. For ASF, CSF and FMD, the risk factor ‘swill feeding’ ranked third. For FMD and the two poultry diseases NCD and AI, only the risk factor ‘air’ was important. Overall conclusion was that conjoint analysis could be a useful method for eliciting the opinion of experts about risk factors concerning contagious animal diseases. In further research, special attention should be given to the selection of experts and the presentation of the conjoint questions.  相似文献   

3.
We developed three different knowledge-dissemination methods for educating Tanzanian smallholder farmers about mastitis in their dairy cattle. The effectiveness of these methods (and their combinations) was evaluated and quantified using a randomised controlled trial and multilevel statistical modelling. To our knowledge, this is the first study that has used such techniques to evaluate the effectiveness of different knowledge-dissemination interventions for adult learning in developing countries.

Five different combinations of knowledge-dissemination method were compared: ‘diagrammatic handout’ (‘HO’), ‘village meeting’ (‘VM’), ‘village meeting and video’ (‘VM + V’), ‘village meeting and diagrammatic handout’ (‘VM + HO’) and ‘village meeting, video and diagrammatic handout’ (‘VM + V + HO’). Smallholder dairy farmers were exposed to only one of these interventions, and the effectiveness of each was compared to a control (‘C’) group, who received no intervention. The mastitis knowledge of each farmer (n = 256) was evaluated by questionnaire both pre- and post-dissemination.

Generalised linear mixed models were used to evaluate the effectiveness of the different interventions. The outcome variable considered was the probability of volunteering correct responses to mastitis questions post-dissemination, with ‘village’ and ‘farmer’ considered as random effects in the model. Results showed that all five interventions, ‘HO’ (odds ratio (OR) = 3.50, 95% confidence intervals (CI) = 3.10, 3.96), ‘VM + V + HO’ (OR = 3.34, 95% CI = 2.94, 3.78), ‘VM + HO’ (OR = 3.28, 95% CI = 2.90, 3.71), ‘VM + V’ (OR = 3.22, 95% CI = 2.84, 3.64) and ‘VM’ (OR = 2.61, 95% CI = 2.31, 2.95), were significantly (p < 0.0001) more effective at disseminating mastitis knowledge than no intervention.

In addition, the ‘VM’ method was less effective at disseminating mastitis knowledge than other interventions. Combinations of methods showed no advantage over the diagrammatic handout alone. Other explanatory variables with significant positive associations on mastitis knowledge included education to secondary school level or higher, and having previously learned about mastitis by reading pamphlets or attendance at an animal-health course.  相似文献   


4.
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5.
The effects of weaning age, type of creep diet and the classification of piglets as ‘eaters’ or ‘non eaters’ of creep feed on weight gain to weaning were examined. Four antimicrobial-free diets were offered from day 14 of lactation: (i) wheat-soy based diet with animal and vegetable (‘mixed’) protein sources (COMM), (ii) heat-processed rice (HPR) with barley hulls and potato starch and mixed protein sources (RBPS), (iii) HPR with sugar-beet pulp and mixed protein sources (RSBP), and (iv) HPR with mixed protein sources (R). Pigs were weaned at an average of either 27 (early) or 33 (late) days of age. A dye (indigo carmine) was added to each diet at day 24 of lactation in both groups to classify piglets as ‘eaters’ or ‘non eaters’ of creep feed, based on appearance or non-appearance, respectively, of dye in faeces. Pigs weaned late weighed 1.4 kg more (P < 0.001). Weaning age interacted with diet type and eating classification for weaning weight (P < 0.001). Of the 1067 piglets where classification of the faecal dye was possible, 829 (77.7%) were ‘eaters’ and 238 (22.3%) were ‘non eaters’. This qualitative estimate of creep feed consumption did not influence weight gain to weaning (P > 0.05).  相似文献   

6.
Sixty-one Mycobacterium avium subsp. paratuberculosis isolates from cattle and deer from the Buenos Aires province, an important livestock region in Argentina, were typed by restriction fragment length polymorphisms (RFLP) analysis based on IS900. Four different RFLP patterns (designated ‘A’, ‘B’, ‘C’ and ‘E’) were identified in BstEII digests of genomic DNA. The most frequently observed type, pattern ‘A’, was found in 46 isolates (75%). The second, pattern ‘E’, included 8 isolates (13%), while the third, pattern ‘B’, included 6 isolates (10%). Pattern ‘C’ was found for only one isolate. All of the deer isolates were classified as pattern ‘A’, while cattle isolates represented all four RFLP patterns. Twenty-one isolates representing the four different BstEII-RFLP patterns were digested with PstI. Twenty isolates showed identical PstI-RFLP pattern. BstEII-RFLP patterns from Argentine cattle and deer were compared with patterns found in cattle, goat, deer, rabbit, and human isolates from Europe. The most common pattern in Argentina, pattern ‘A’, was identical to a less frequently occurring pattern R9 (C17) from Europe. The other Argentine patterns ‘B’, ‘C’ and ‘E’, were not found in the Europe. These results indicate that the distribution of M. avium subsp. paratuberculosis genotypes in the Buenos Aires province of Argentina is different from that found in Europe.  相似文献   

7.
A total of 796 sows and gilts from 30 Danish sow herds were examined three times at intervals of 6 weeks for serum antibodies to Leptospira bratislava by the microscopic agglutination technique (MAT) test. The prevalence of seroreactors with positive titer values, 1:100, at the three successive tests were 2.7%, 2.5% and 2.9%; 4.5% of the animals were positive in at least one of the three tests, and 2.2% showed a greater than two-fold rise in titer between two consecutive samplings. Of the 30 herds, 21 (70%) had ever-positive within-herd prevalences in sows and gilts of 4–13%. The risk of a herd having one or more positive sow was positively associated with a herd size of > 141 sows, and distinct regional differences in the prevalence of positive herds were observed. The reproductive performance of the 21 herds with seroreactions was poorer than the performance of the nine herds without positive reactions concerning the variables: ‘days from weaning to last service’ (2.7 days more, P = 0.07), ‘percentage of sows returning to heat’ (4.0 percentage units more, P = 0.03), ‘services per farrowing’ (0.04 more, P = 0.04), ‘farrowing percentage’ (4.3 percentage units lower, P = 0.06), and ‘stillborn pigs per farrowing’ (0.16 more, P = 0.02). No association between the MAT serological status of the herd and the incidence of medical treatments of sows and gilts could be found. A high prevalence and low cumulative incidence of seroreactors was demonstrated in first-parity gilts, followed by a low prevalence and cumulative incidence from parity 2 to 3, and a high prevalence and cumulative incidence at the fifth parity.  相似文献   

8.
Eighteen crossbred boars, three siblings from each of six litters, were distributed randomly among three groups after weaning. The ‘Natural long-day’ group was housed in a standard room with windows, whereas the ‘Artificial long-day’ and ‘Artificial short-day’ groups were housed in light-sealed rooms and under an artificial light regimen (1400 lx). In spring (16–17 hr of light) plasma levels of melatonin and cortisol were measured in samples collected hourly for 24 hr. Two commercial melatonin radioimmunoassays with preassay diethyl ether extraction were compared. Only the assay from Bühlmann Laboratories AG showed low to undetectable melatonin levels during the light-phase and was used for further analysis. Dark-phase melatonin concentrations were higher than light-phase melatonin concentrations (P < 0.001). Dark-phase melatonin concentrations were higher in the ‘Natural long-day’ group than in the ‘Artificial long-day’ and the ‘Artificial short-day’ groups (P < 0.001). Sire had a significant effect on dark-phase melatonin concentrations (P < 0.01), but not on light-phase levels. Cortisol concentrations were higher during the light-phase than during the dark phase, and light-phase cortisol concentrations were higher in the ‘Natural long-day’ group than in the ‘Artificial long-day’ and the ‘Artificial short-day’ groups (P < 0.01). This study showed that peripubertal boars express a typical circadian melatonin rhythm under both artificial light regimens and in standard pig stable environment. Natural photoperiod and indoor lighting seem to interact in shaping the melatonin profile in standard stable environment. The great individual variation in the amplitude of the dark-phase melatonin levels could in this study be explained by the different sires.  相似文献   

9.
The rate and structure of cattle transfers between 206 Dutch cattle herds with a ‘Mycobacterium avium subsp. paratuberculosis (Map)-free’ status by November 2002, were analyzed over a 3-year period (November 1999–November 2002). Of the 206 ‘Map-free’ herds, 184 were closed herds during the period studied. In total, 280 cattle had been introduced into 22 herds at an average rate of 0.33 animals per year per 100 cattle present in the 206 herds. Assuming a random herd-contact structure, the observed rate of cattle transfers between certified ‘Map-free’ herds was sufficiently low to relax the surveillance scheme to biennial herd examinations by pooled fecal culture of all cattle ≥2 years of age.

The cattle transfers were not randomly distributed over the herds. Forty-four of the 280 cattle originated from 12 other ‘Map-free’ herds. The other 236 cattle did not originate from a ‘Map-free’ herd and were introduced into a herd before it obtained the ‘Map-free’ status. No cattle were introduced into any of the ‘Map-free’ herds from which cattle were transferred to other ‘Map-free’ herds. Thus, continued propagation of the infection by cattle transfers was impossible in the group of herds studied during the study period. Therefore the surveillance scheme may be further relaxed, and may be differentiated regarding the risk herds pose to other herds.  相似文献   


10.
The validity of producer-recorded preweaning mortality causes was evaluated in 31 Danish sow herds. For 1206 piglets producer-recorded preweaning mortality cause was compared with post-mortem diagnosis. The predominant preweaning mortality causes at post-mortem were injury (trauma, lain on, and savaged), miscellaneous (unknown, starvation, illthrift, euthanasia, and low viability), and diarrhoea, with 391, 219, and 119 recordings, respectively. The sensitivity of producer-recorded preweaning mortality causes was generally low, and further analyses showed that the probability of being born alive and the probability of being given ‘a producer diagnosis other than unknown’ were associated with the herd and that a correct producer-recorded mortality cause relative to the post-mortem diagnosis depended on the mortality cause. Rare mortality causes with primarily internal signs tended to be misclassified. The producers often gave ‘a diagnosis other than unknown’ to pigs with a weight at death under 0.75kg and it was often correct. To pigs with a weight at death over 1.75kg, they rarely gave ‘a diagnosis other than unknown’, but when they did it was often correct.  相似文献   

11.
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12.
An in vitro study was performed to describe the effect of addition of acid products to liquid feed on the course of fermentation. A standard grower diet with added extra lysine, methionine, and threonine was formulated. Three experimental treatments were prepared: the grower diet, ‘Control’; the grower diet + 4.8 g solid acidifier Boliflor® FA 2300S/kg liquid feed, ‘FA2300S’; and the grower diet + 2.0 g formic acid/kg liquid feed, ‘Formic’. Feed and water (1 to 2.75) were incubated in bioreactors with a volume of 1 l at 20 °C. A sample was taken after 0, 6, 24, and 48 h of incubation. After 48, 55, 72, 79, and 96 h of incubation, 90% of the mixture was removed and replaced with fresh feed and water. A sample was taken at 96, 102, and 108 h of incubation. Enterobacteriaceae counts were highest in the ‘Control’ diet and lowest in the ‘Formic’ diet at all sampling times. From 96 to 108 h of incubation,  5–19% total lysine, threonine, and methionine, and  26–42% free lysine, threonine, and methionine disappeared. Addition of 2.0 g formic acid or 4.8 g Boliflor® FA 2300S per kg pig liquid feed impeded a blooming of Enterobacteriaceae during the first hours of fermentation but had no effect on amino acid degradation. A disappearance of, mainly, free amino acids occurred during fermentation of liquid feed as prepared in the present study.  相似文献   

13.
The epidemiologies of the most common diseases diagnosed in pigs at the Danish pig-breeding test stations were studied with special reference to possible genetic predisposition. The population under study comprised 9084 test pigs (corresponding to 3028 test groups) housed at nine test stations from September 1983 to September 1984. There were substantial differences between the four breeds in the study (Landrace, Yorkshire, Duroc and Hampshire) with the white breeds having higher clinical incidences of respiratory diseases and culling rates than the coloured ones. In only one of nine analyses was a significant sire effect found. However, significant differences were found between breeding centres of origin. There was a negative influence of clinical diseases on daily gain and feed conversion. Classifying respiratory disease in an ‘early’ form (at least one pig in the group was treated during the first 45 days of the test period) and a ‘late’ form (treatments were given after this period) showed that late infections resulted in a higher reduction of performance than early infections did. There were no associations between pathological findings at slaughter and growth rate.  相似文献   

14.
We quantified the effect of Neospora caninum (NC)-serostatus on culling and (re)production in 83 herds randomly selected from the Dutch dairy herd population (random group) and in 17 herds that had experienced an abortion epidemic associated with NC infection (epidemic-abortion group). In the random group, a single whole-herd blood sampling was done during the spring of 2003, while in the epidemic-abortion group whole-herd blood sampling was done repeatedly at least once a year starting after the abortion epidemic during the period 1997–2000 until the summer of 2004. Serological test-results for NC were given as ‘negative’ (N), ‘low-positive’ (LP) and ‘high-positive’ (HP). For analysing the time to culling, calving interval and age of first calving, survival analysis was used. For categorical reproduction parameters either a logistic-regression model (abortion, non-return after 1st insemination) or a Poisson-regression model (number of inseminations per pregnancy) was used. For milk production a linear-mixed model was used. All models were controlled, if applicable, for confounding variables like parity, production, season, year and abortion and adjusted for within-herd clustering.

In random herds, HP serostatus increased the hazard for culling 1.73-fold (95% CI: 1.37–2.19) compared to N and LP serostatus. Compared to N serostatus, LP and HP serostatus in epidemic-abortion herds increased the odds for abortion 1.88-fold (95% CI: 1.41–2.52) and 1.72-fold (95% CI: 1.38–2.14), respectively. No other reproduction parameters were associated with NC-serostatus in the random or epidemic-abortion herds. We found no effect of serostatus on milk production in the random group. In contrast, milk production of LP and HP serostatus in the epidemic-abortion group was respectively, 0.72 kg milk/day (95% CI: 0.15–1.03) and 0.59 kg milk/day (95% CI: 0.13–1.30), less during the first 100 days of lactation in the first year after the abortion epidemic compared with N serostatus.  相似文献   


15.
This study investigated the effects of weaning age, diet, and classification of piglets as ‘eaters’ or ‘non eaters’ of creep feed in lactation, on production and diarrhoea after weaning. Four antimicrobial-free diets were offered in lactation and for 14 days after weaning: (i) wheat–soy based diet with animal and vegetable (‘mixed’) protein sources (COMM), (ii) heat-processed rice (HPR) with barley hulls and potato starch and mixed protein sources (RBHPS), (iii) HPR with sugar-beet pulp and mixed protein sources (RSBP), and (iv) HPR with mixed protein sources (R). Piglets were individually examined for diarrhoea daily for 14 days after weaning, and antibiotic treatments were individually recorded. Faecal swabs were taken on day 10 after weaning and scored for β-haemolytic Escherichia coli. There were significant main effects of weaning age and diet (both P < 0.001) on daily gain between weaning and 14 days after weaning. Pigs weaned later grew 50 g/day more than pigs weaned earlier, and pigs fed the COMM diet grew slower than pigs fed the rice-based diets. The number of antibiotic treatments was influenced by diet (P < 0.001), with most treatments (2.1) given to pigs fed the diet RBHPS. Faecal score was influenced by a weaning age and diet interaction (P < 0.01). There was no correlation (P > 0.05) between the number of antibiotics treatments and the E. coli score.  相似文献   

16.
The National Animal Health Monitoring System (NAHMS) (Round 2) for Tennessee collected baseline data on the preventive (as opposed to therapeutic) use of drugs from 60 beef cow-calf herds selected by a random, stratified, two-stage sampling plan. Counties were selected randomly with replacement for three herd-size strata, and herds were selected within countries by an area-frame method. Data were collected during monthly interviews for 1 year (1987–1988).

Tennessee beef cattle were medicated with 31 drugs to prevent diseases. The drugs most frequently used were anthelmintics and insecticides. The diseases against which preventive drugs were most frequently used were external parasites, intestinal parasites, ‘pink eye’ (keratoconjunctivitis), anaplasmosis, and respiratory infections. Ivermectin was the most frequently used anthelmintic and the most frequently used drug. Levamisole, fenbendazole, and thiabendazole were also frequently used anthelmintics. The most frequently used insecticides were the organophosphates (including fenthion, dichlorvos, and stirofos). Antimicrobials seldom were used, suggesting that prophylactic antimicrobial use in Tennessee beef cattle may not be a major public-health concern.  相似文献   


17.
We did a test-retest study on 21 farms to assess the repeatability of the Dairy Heifer Health Report of the National Dairy Heifer Evaluation Project. The median retest interval was 42 days (range 14–63 days), retest interviewers were blinded as to responses on the first visits, and all date-specific questions were anchored to the dates of the first tests. The overall discrepancy percentage was 8.5% (95% CI 8.0–9.0). Individual farms had discrepancy percentages of 3.0–15.2%; 240 out of the 539 questions had no discrepancies at all, but 81 questions had more than four (out of 21 possible) discrepancies (lowest percentages among the 81: 24%; 95% lower confidence limit on 24%: 6%). Combining ‘no’ and ‘not applicable’ responses for six similarly worded questions in the Biosecurity section would reduce the overall questionnaire discrepancy percentage to 7.8% and would bring that section's discrepancy percentage down to 8.6%. The other discrepancy percentages by section were: Maternity Hygiene, 14.1 %; Preweaning Hygiene, 4.8%; Disease Agents, 3.6%; Vaccination Practices, 12.1%; Preventive Practices, 16.8%. Discrepancy percentages did not differ importantly by type of question (independent, filter, or subordinate) or by type of response required (categorical, count, or measurement). Discrepancy percentages were independent of retest interviewer, test-retest interval and order of test within state (a proxy for time since training of the interviewers) but were correlated with herd size (rsp = 0.59).  相似文献   

18.
Viruses differ from other infectious agents mainly in two respects: (a) they may be generated in the genome of normal cells and, in other instances, reinserted into the genome as proviruses, (b) they may participate in all pathologic processes that form the main subject of immune surveillance and immunity such as infectious diseases, tumourous growth, and, auto-aggressive processes.

Due to intracellular and cell modifying character of virus infection, the immune mechanisms are often unsuccessful in elimination of the agent from the vertebrate organism and may show disturbances contributing to development of a persistent viral disease. As exemplified by two forms of leprosy, intracellular bacteria may also cause ‘slow’ diseases. Their course, in analogy with viral slow diseases, seems to reflect the changed immunological potential of the infected host.  相似文献   


19.
In this study, two highly pathogenic avian influenza (HPAI) H5N8 viruses were isolated from chicken and geese in 2018 and 2019 (Chicken/ME-2018 and Geese/Egypt/MG4/2019). The hemagglutinin and neuraminidase gene analyses revealed their close relatedness to the clade-2.3.4.4b H5N8 viruses isolated from Egypt and Eurasian countries. A monovalent inactivated oil-emulsion vaccine containing a reassortant virus with HA gene of the Chicken/ME-2018/H5N8 strain and a bivalent vaccine containing same reassortant virus plus a previously generated reassortant H5N1 strain (CK/Eg/RG-173CAL/17). The safety of both vaccines was evaluated in specific-pathogen-free (SPF) chickens. To evaluate the efficacy of the prepared vaccines, 2-week-old SPF chickens were vaccinated with 0.5 mL of a vaccine formula containing 108/EID50 /dose from each strain via the subcutaneous route. Vaccinated birds were challenged with either wild-type HPAI-H5N8 or H5N1 viruses separately at 3 weeks post-vaccine. Results revealed that both vaccines induced protective hemagglutination-inhibiting (HI) antibody titers as early as 2 weeks PV (≥5.0 log2). Vaccinated birds were protected clinically against both subtypes (100 % protection). HPAI-H5N1 virus shedding was significantly reduced in birds that were vaccinated with the bivalent vaccine; meanwhile, HPAI-H5N8 virus shedding was completely neutralized in both tracheal and cloacal swabs after 3 days post-infection in birds that had been vaccinated with either vaccine. In conclusion, the developed bivalent vaccine proved to be efficient in protecting chickens clinically and reduced virus shedding via the respiratory and digestive tracts. The applicability of the multivalent avian influenza vaccines further supported their value to facilitate vaccination programs in endemic countries.  相似文献   

20.
The epidermis of the skin is both a sensitive immune organ and a practical target site for vaccine administration. However, administration of vaccines into the epidermis is difficult to achieve using conventional vaccine delivery methods employing a needle and syringe. A needle-free vaccine delivery system has been developed that efficiently delivers powdered or particulate DNA and protein vaccines into the epidermal tissue. The delivery system can be used to directly transfect antigen presenting cells (APCs) by formulating DNA or protein vaccines onto gold particles (particle-mediated immunization). Antigen can be directly presented to the immune system by the transfected APCs. Antigen can also be expressed and secreted by transfected keratinocytes and picked up by resident APCs through the exogenous antigen presentation pathway. Alternatively, protein antigens can be formulated into a powder and delivered into the extracellular environment where they are picked up by APCs (epidermal powder immunization). Using any of these formulations, epidermal immunization offers the advantage of efficiently delivering vaccines into the APC-rich epidermis. Recent studies demonstrate that epidermal vaccine delivery induces humoral, cellular, and protective immune responses against infectious diseases in both laboratory animals and man.  相似文献   

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