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111.
112.
Connolly Dj Dwyer P Fagan J Hayes M Ryan E Costello E Kilroy A More S 《Irish veterinary journal》2008,61(8):533-537
Tuberculosis (TB), due to infection with Mycobacterium bovis was diagnosed in a flock of alpaca in Ireland in 2004. An epidemiological investigation was conducted to identify the risk of TB for farmed alpaca where TB is endemic, the origin of the infection, the potential for alpaca-to-alpaca transmission and appropriate control measures. The investigation focused on the alpaca flock (including the farm, animal movements and breeding, feeding and flock health practice), the disease episode (including animal disease events and subsequent control measures) and TB infection risk in the locality. The TB risk to alpaca is high in areas where infection is endemic in cattle and badgers and where biosecurity is inadequate. It is most likely that the source of infection for the alpaca was a local strain of M. bovis, present in cattle in this area since at least 2001. Genotyping of isolates identified a single variable number tandem repeat (VNTR) profile in both cattle and alpaca in this region. Although a tuberculous badger was also removed from the vicinity, bacterial isolation was not attempted. On this farm, infection in alpaca was probably derived from a common source. Alpaca-to-alpaca transmission seems unlikely. Two broad control strategies were implemented, aimed at the rapid removal of infected (and potentially infectious) animals and the implementation of measures to limit transmission. Tests that proved useful in detecting potentially-infected animals included measurement of the albumin-to-globulin ratio and regular body condition scoring. Skin testing was time consuming and unproductive, and early detection of infected animals remains a challenge. The flock was managed as a series of separate groupings, based on perceived infection risk. No further TB cases have been detected. 相似文献
113.
磷酸泰乐菌素是一种以提高动物生长为目的、被批准能以亚治疗剂量在肉鸡饲料中使用的抗菌药物,而红霉素通常是用来治疗人弯曲杆菌病的首选药物,这两种药物均属于大环内酯类药物,它们之间存在着交叉耐药性。本试验将商品肉鸡单独饲养在生长肥育鸡舍,并使其感染空肠弯曲杆菌。试验组肉鸡从14日龄起至出栏之间自由采食含有0.022‰磷酸泰乐菌素(22g/t)的饲料,对照组肉鸡饲喂组成相同但不添加磷酸泰乐菌素的饲料。在42日龄时,全部肉鸡在一个严格模拟商业性屠宰加工条件的中试屠宰加工厂进行屠宰加工。分别收集肉鸡屠体脱毛后、胴体内外冲洗后和胴体浸没式冷却后的屠体或胴体清洗液。结果表明,两组肉鸡屠体脱毛后清洗液所含弯曲杆菌在数量上无显著性差异(对照组肉鸡为3.53logcfu/mL,药物试验组为3.60logcfu/mL)。同样,饲料中添加药物不会影响肉鸡胴体内外清洗液中的弯曲杆菌含量(分别为3.11和3.07logcfu/mL)。然而,药物试验组肉鸡胴体浸没式冷却液中的弯曲杆菌数量(1.45logcfu/mL)少于对照组(2.31logcfu/mL)。试验时未能从对照组肉鸡屠体清洗液中分离到红霉素耐药性弯曲杆菌,而从药物试验组肉鸡屠体/胴体清洗液中分离到的所有弯曲杆菌均为红霉素耐药性菌株。饲料中添加磷酸泰乐菌素会减少肉鸡胴体冷却液中弯曲杆菌的数量,然而屠体上存活的弯曲杆菌对红霉素具有耐药性。 相似文献
114.
Genetic diversity and toxin gene distribution among serovars of Actinobacillus pleuropneumoniae from Australian pigs 下载免费PDF全文
Objective
To explore the diversity among isolates of the Actinobacillus pleuropneumoniae serovars most common in Australia (serovars 1, 5, 7 and 15) and to examine the Apx toxin profiles in selected representative isolates.Design
A total of 250 isolates selected from different farms were examined for their genotypic profiles and a subset of 122 isolates for their toxin profiles.Methods
The isolates of serovars 1, 5, 7 and 15 selected for this study came from different farms and different Australian states and were submitted for serotyping to the reference laboratory. The overall diversity of the strains was explored with the enterobacterial repetitive intergenic consensus (ERIC) PCR and the presence of the toxin genes was investigated with a toxin PCR assay.Results
Some degree of variation was observed in the ERIC‐PCR pattern within all four serovars, ranging from 38% to 61% genetic diversity. When looking at the toxin gene profile and, therefore, the predicted ability to produce the expected toxin pattern, one isolate each of serovars 1 (n = 20) and 7 (n = 47) and 17 isolates of serovar 15 (n = 40) showed variation to the expected gene profile.Conclusion
The variations in toxin gene patterns, as detected by PCR, found in this study could be related to significant changes in the gene sequence or total absence of the gene. Variation in toxin gene sequences has been observed in other countries. This variation in the toxin profile could also explain possible variation in pathogenicity observed in the field. 相似文献115.
116.
Effect of different mini‐volume colloid centrifugation configurations on flow cytometrically sorted sperm recovery efficiency and quality using a computer‐assisted semen analyzer 下载免费PDF全文
LB Ferré JL Chitwood C Fresno HH Ortega ME Kjelland PJ Ross 《Reproduction in domestic animals》2018,53(1):26-33
Straws of sex‐sorted sperm are usually packaged at a low concentration (e.g., ~2.1 × 106 sperm/ml) and cost significantly more than unsorted conventional semen from the same sire. In order to maximize the efficiency of using sex‐sorted sperm under in vitro fertilization conditions, the selection of an appropriate sperm separation technique is essential. In this study, the effect of using different silane‐coated silica colloid dilutions and layering configurations during centrifugation of sex‐sorted sperm was examined over an extended period of incubation time. Sperm recovery and viability after centrifugation using the colloid separation technique were measured along with several sperm motility parameters using CASA. For this purpose, frozen and thawed sex‐sorted sperm samples were centrifuged using mini‐volume single‐layer (40%, 60% and 80%) and mini‐volume two‐layer (45%/90%, 40%/80% and 30%/60%) separation configurations using PureSperm®. A single layer of 40% PureSperm® recovered significantly more sex‐sorted sperm (78.07% ± 2.28%) followed by a single layer of 80% PureSperm® (68.43% ± 2.33%). The lowest sperm recovery was obtained using a two‐layer PureSperm® dilution of 45%/90% (47.57% ± 2.33%). Single‐layer centrifugation recovered more sorted sperm (68.67% ± 1.74%) than two layer (53.74% ± 1.74%) (p < .0001). A single layer of 80% PureSperm® exhibited the highest sorted sperm viability (72.01% ± 2.90%) after centrifugation (p < .05). The mini‐volume single layer of 80% PureSperm® was determined to be an effective alternative to a two‐layer centrifugation configuration for sex‐sorted sperm selection. In addition, single‐layer colloid dilution of 80% performed either as well as or significantly outperformed the other treatments, as well as the control, with regard to motility (MOT) for all time periods of analysis. 相似文献
117.
Objective To evaluate the effect of the number of days exposure to a prepartum transition diet on reproduction and health in dairy cows. Design A prospective cohort study. Procedures We enrolled 1008 dairy cows from three herds to examine the effects on reproduction and health of increased days exposure to prepartum transition diets that included ryegrass pasture, ryegrass silage, cereal hay, grain, by-products, oilseed meals, BioChlor®, rumen modifiers, minerals and vitamins. Diets provided 9.9 MJ metabolisable energy per kg dry matter (DM), a metabolisable protein balance of 286 g/day and a dietary cation anion difference of −150 meq/kg DM. Statistical models controlled for herd, calving day, age and gestation period. Results In two of the three herds increased days exposure to prepartum transition diets increased the hazards of submission for breeding, conception and clinical mastitis, and decreased the hazard of cow removal. The odds of pregnancy by 6 and 21 weeks after the mating start date tended to increase with increasing days of exposure to prepartum transition diets. Conclusions Increasing exposure to a prepartum transition diet improved the calving to conception interval, tended to improve the odds of pregnancy and reduced the risk of culling of cattle, but increased the hazard of clinical mastitis. 相似文献
118.
PJ Collins Emily Mulherin Olivia Cashman Grainne Lennon Lynda Gunn Helen O’Shea Séamus Fanning 《Irish veterinary journal》2014,67(1):13
Background
Worldwide, Group A bovine rotavirus (RVA boRV) is one of the main causes of neonatal calf diarrhoea. Currently, limited epidemiological and sequence data exists on the RVA disease in bovines in Southern Ireland only. The aim of the study was to generate epidemiological and sequence data of RVA boRV distributed over a wide geographical area in Ireland.Findings
272 stool samples were obtained from symptomatic calves and analysed to identify the prevalent G and P genotypes. Viral type combinations including G6P[5], G6P[11] and G10P[11] genotype were the most frequently identified. The G6P[5] combination was predominant throughtout the study, accounting for 70% (n = 191). Sequence analysis of the VP7 gene revealed that Irish G6 strains fell within Lineage IV, similiar to previous reports in Ireland.Conclusion
The detection of unusual G and P combinations may have an impact on rotavirus control programmes and current vaccines may need to incorporate new strains, as the current vaccine available may not offer protection against all of these circulating types. 相似文献119.
PJ Kwong HY Nam WE Wan Khadijah T Kamarul RB Abdullah 《Reproduction in domestic animals》2014,49(2):249-253
The aim of this study was to produce cloned caprine embryos using either caprine bone marrow‐derived mesenchymal stem cells (MSCs) or ear fibroblast cells (EFCs) as donor karyoplasts. Caprine MSCs were isolated from male Boer goats of an average age of 1.5 years. To determine the pluripotency of MSCs, the cells were induced to differentiate into osteocytes, chondrocytes and adipocytes. Subsequently, MSCs were characterized through cell surface antigen profiles using specific markers, prior to their use as donor karyoplasts for nuclear transfer. No significant difference (p > 0.05) in fusion rates was observed between MSCs (87.7%) and EFCs (91.3%) used as donor karyoplasts. The cleavage rate of cloned embryos derived with MSCs (87.0%) was similar (p > 0.05) to those cloned using EFCs (84.4%). However, the in vitro development of MSCs‐derived cloned embryos (25.3%) to the blastocyst stage was significantly higher (p < 0.05) than those derived with EFCs (20.6%). In conclusion, MSCs could be reprogrammed by caprine oocytes, and production of cloned caprine embryos with MSCs improved their in vitro developmental competence, but not in their fusion and cleavage rate as compared to cloning using somatic cells such as EFCs. 相似文献
120.
Bahnson PB Fedorka-Cray PJ Ladely SR Mateus-Pinilla NE 《Preventive veterinary medicine》2006,76(3-4):249-262
Midwest U.S. herds (n = 63) were studied to identify risk factors for harboring Salmonella enterica among slaughter-weight pigs. Samples collected on farms (feces) and at slaughter (distal colonic content, cecal content and ileocolic lymph nodes) were cultured using conventional means. Approximately 15 pigs were studied per herd, for a total of 3754 samples. The proportion of pigs positive in one or more samples was calculated for each herd. Herd characteristics were described by a combination of interview and written survey. Logistic regression was used to detect relationships between the detection of Salmonella and potential herd-level risk factors. The mean individual pig prevalence was 5% for feces, 4% for distal colonic content, 15% for ileocolic lymph nodes, and 17% for cecal contents. One or more Salmonella isolates were detected in at least one sample type in every herd. The five most common serovars were S. Agona, S. Derby, S. Schwarzengrund, S. Typhimurium and S. Senftenberg, with 25 additional serovars detected. Salmonella prevalence estimates were positively correlated among all samples except distal colonic content and ileocolic lymph nodes. Pigs with culture positive fecal samples were at increased odds of being detected positive for each of the slaughter-collected samples examined, namely distal colonic content (OR = 30.5), ileocolic lymph nodes (OR = 12.9) and cecal content (OR = 23.2). Herds with positive fecal sample(s) had increased odds of having positive cecal content (OR > 1.5), distal colonic content (OR = 15.3) and ileocolic lymph nodes (OR = 12.7). Pigs from herds with at least some bowl drinkers had eight-fold higher odds of testing Salmonella positive than did pigs from herds with only nipple drinkers. Pigs from herds with only dry feeders had five-fold higher odds of testing Salmonella positive when compared with pigs from herds with combinations of wet/dry style feeders. Interventions at these two points should be considered when designing growing pig facilities to reduce Salmonella shedding. 相似文献