雏鸡喹乙醇中毒血液生化指标测定

为探讨喹乙醇急性中毒雏鸡血液生化指标的变化情况,。将200只5日龄伊莎公鸡雏随机分为2组,对照组饲喂基础饲粮,试验组饲喂基础饲粮+150mg/kg喹乙醇。在染毒后5、10、15d,对相关血液生化指标进行检测。结果表明,喹乙醇中毒时,在各时间点,试验组血清K+含量均高于对照组,在15d差异显著(P<0.05);试验组血清中Ca2+、PO43-、Na+含量均低于对照组,在15d差异均显著(P<0.05);试验组血清ALB、TP含量均低于对照组,ALB在15d差异显著(P<0.05),TP在10d和15d差异显著(P<0.05);试验组血清ALP、GOT、GPT活性高于对照组,GOT、GPT在15d差异显著(P<0.05)。结果显示喹乙醇中毒能够引起雏鸡相关血液生化指标的改变,喹乙醇有一定的蓄积毒性。     

Consequences of selection for improving production traits on the frequency of deleterious alleles for fitness

In this study the effect of artificial selection on BLUP EBV for production traits on the allele frequencies of a pleiotropic QTL affecting both production and disease susceptibility was investigated. Stochastic simulations were used to model artificial selection on a production trait that is controlled, in part, by a biallelic QTL that also controls susceptibility to disease. The QTL allele increasing production also increased susceptibility to disease. Different modes of action and proportions of variation accounted for by the QTL were assessed for the production trait. The main results indicated that alleles that confer susceptibility to the disease could be maintained in the population over a long period, depending on the mode of action of the QTL. In addition, the results of the study indicate that, under various conditions, it is possible to find pleiotropic QTL that control 2 traits despite these traits appearing to be uncorrelated. Therefore, in practice, an estimate of the genetic correlation between 2 traits may be misleading when the presence of such a QTL exists. The results of this study have implications for breeding programs. For example, if a pleiotropic QTL exists that favors heterozygotes for a production trait, it would be very difficult to remove disease susceptibility alleles via traditional selection methods.     

Estimating parameters of growth curves of bulls

Parameters were estimated for nonlinear growth curves for bulls of five straightbred and 20 crossbred breed-types produced in two generations of a diallel. The primary intent of this study was to use the estimates obtained for mature size and maturing rate to define male growth in manner that would be appropriate for use in the Texas Agricultural Experiment Station (TAES) Beef Cattle Simulation Model. The results that were obtained from the nonlinear regressions made on the male growth data indicated that the relation between the mature sizes of males and females of the same breed-type is consistent with the assumption for that relation contained in the model (a ratio of 1.5). However, the inverse relationship between mature size and maturing rate that is assumed in the model was not consistent with the results of the present study. That contradiction presumably arose due to the different environment imposed on the males relative to their female counterparts. This condition prohibits direct application of the results of this study because live weights cannot be directly related to the principal growth curve contained in the model. However, such a relationship can be developed when information regarding the composition of bulls considered in this study becomes available.     

Genetic evaluation of the probability of pregnancy at 14 months for Nellore heifers

To estimate the heritability for the probability that yearling heifers would become pregnant, we analyzed the records of 11,487 Nellore animals that participated in breeding seasons at three farms in the Brazilian states of S?o Paulo and Mato Grosso do Sul. All heifers were exposed to a bull at the age of about 14 mo. The probability of pregnancy was analyzed as a categorical trait, with a value of 1 (success) assigned to heifers that were diagnosed pregnant by rectal palpation about 60 d after the end of the breeding season of 90 d and a value of 0 (failure) assigned to those that were not pregnant at that time. The estimate of heritability, obtained by Method R, was 0.57 with standard error of 0.01. The EPD was predicted using a maximum a posteriori threshold method and was expressed as deviations from 50% probability. The range in EPD was -24.50 to 24.55%, with a mean of 0.78% and a SD of 7.46%. We conclude that EPD for probability of pregnancy can be used to select heifers with a higher probability of being fertile. However, it is mainly recommended for the selection of bulls for the production of precocious daughters because the accuracy of prediction is higher for bulls, depending on their number of daughters.     

Nutrition of rodents.

Access to a diet that provides adequate nutrition is one of the most important environmental factors influencing the well-being of rodent colonies. The dietary ingredient and nutrient composition, as well as the potential biological and chemical contaminant concentrations, are factors for consideration in selecting diets for a specific rodent colony. Estimated nutrient requirements have been published for the rodent species that are commonly used in biomedical research. The nutrient concentrations in adequate diets for other captive rodent species that are not used in biomedical research are more difficult to obtain. However, reasonable estimates of their nutrient requirements can be obtained by extrapolation of data from rodent species of a similar metabolic weight and size or from nutrient concentrations of diets that have a history of acceptable performance in the species of interest. Captive rodent colonies should be provided with nutritionally balanced diets with only limited amounts of succulent foodstuffs. The practice of feeding rodent colonies specific cereal grains is discouraged, since no single grain provides a balanced rodent diet.     

Analyzing the effect of different approaches of penalized relationship in multistage selection schemes

The aim of this study was to extend optimum contribution selection to more realistic breeding schemes with multistage selection. It seems that if the last selection stage accounts for the relationship of the selected animals, then previous selection stages also account for this relationship. An extreme example was considered here: the preselection of dairy bulls that enter a progeny testing scheme. First the penalty on the average relationship in selection step 1 is assumed the same as in step 2. Thereafter, situations with different penalties on the average relationship in the 2 selection steps were analyzed. The simulation started with the generation of prior EBV, which were sampled from a truncated normal distribution. Possible candidates for further progeny testing were selected and progeny test EBV were simulated, where the progeny test was based on 100 daughters per young bull. In situations with greater accuracy of prior EBV, high trait heritability and prior EBV were available for 2,000 bulls; the results were similar for both approaches, independent of family size. However, in a situation with low accuracy of prior EBV and low trait heritability it could be observed that with increasing penalty on the average relationship, correction for relationship in stage 1 yielded in a similar genetic level compared with selecting only for high prior EBV. If the number of bulls with prior EBV increased from 2,000 to 4,000, an increasing penalty on an average relationship gave an improved genetic level. A further improvement of the results with respect to genetic level and average relationship could be observed by increasing the penalty on an average relationship in selection step 1 above that in selection step 2. Overall, this study showed that it is beneficial to use a penalty on an average relationship already for the selection of bulls that enter the progeny test. In case optimum contribution was applied with a constraint on the average relationship in stage 2, this constraint may be translated into a penalty on the average relationship, and the current results suggested that the optimal penalty in selection stage 1 should be twice that of stage 2.     

Welfare consequences of mulesing of sheep

Mulesing is traditionally performed on approximately 80% of Merino wool-producing sheep in Australia. Mulesing produces a stress response that persists for 24 to 48 hours. Behavioural changes indicative of pain and discomfort resolve within 24 and 48 hours, respectively. Reductions in weight gain may persist for 14 days. The acute stress response to mulesing has been shown to be similar to that produced by shearing, castration and mild flystrike, but mulesing has a longer duration of response (24 to 48 hours) than shearing (1 hour) or knife castration (8 to 24 hours), whereas flystrike response persists for the duration of infection. Theoretically, if mulesing were not used, with Merino sheep of existing genetics, increased chemical use and flock inspections could keep flystrike rates to approximately equivalent to present levels in some production systems. Increased handling events for chemical preventative application would represent a mild stressor for sheep, but cumulatively not more than that of mulesing. If producers were able and prepared to sufficiently increase resources into alternative anti-flystrike methods, then the welfare of Merino sheep would probably be equivalent or better to that of today. If constraints such as property size or finances dictate a sub-optimal level of flystrike prevention and treatment, then animal welfare will unquestionably be worse. The result of that equation would depend on individual flock managers, the physical characteristics of their production system, the profitability of their business, and seasonal variations in flystrike risk. It is likely that there would be some occasions when flystrike would increase. This highlights the need for alternative strategies, such as genetic selection, to reduce the susceptibility of Australian Merino sheep to flystrike.     

Genotyping of groups of cows to improve genomic breeding values of new traits

Genotyping females and including them into the reference set for genomic predictions in dairy cattle is considered to provide gains in reliabilities of estimated breeding values for selection candidates. This should especially be true for low heritability traits. By the use of simulation, we extended a genomic reference set for an existing trait by including a fixed number of genotyped first‐crop daughters for one or two generations of reference sires. Moreover, we calculated results for the effects of a similar strategy in a situation where for a new trait the recording of phenotypes has recently started. For this case, we compared the effect of two different genotyping strategies: first, to phenotype cows but to genotype their sires only, and second, to collect phenotypes and genotypes on the same cows. We studied the effects on validation reliabilities and unbiasedness of predicted values for selection candidates. We found that by extending the reference set with genotyped daughters it is possible to increase the validation reliability of genomic breeding values. In the case of a new trait, it is always better to collect and use genotypes and phenotypes on the same animals instead of using only sire genotypes. We found that the benefits that can be achieved are sensitive to the sampling strategy used when selecting females for genotyping.     

A comparison of methods to estimate the prevalence of ovine Johne's infection from pooled faecal samples

OBJECTIVE: To compare estimates of ovine Johne's infection prevalence produced by several alternate methods based on pooled faecal culture (PFC) results with prevalence estimates based on individual faecal culture (IFC). PROCEDURE: Seven methods for estimating prevalence of infection based on PFC results were incorporated in a computer program, including methods for imperfect test sensitivity and specificity, for variable pool size and a Bayesian method that incorporates prior knowledge about test performance and prevalence. These methods were then used to analyse PFC data at one observation 30 months post-vaccination in a field trial of a killed vaccine for the control of OJD, undertaken on three farms in New South Wales. RESULTS: Prevalence estimates, for three methods that assume a perfect test, were close to the IFC estimate, whereas for three other methods that assume an imperfect test, the estimated prevalence was generally higher than the IFC estimate. In comparison, the Bayesian approach produced more variable estimates that were substantially higher than the IFC estimate when an inappropriately high prior estimate of prevalence was used. CONCLUSION: Despite the limitations of each method, two methods provided accurate and reasonable estimates of the prevalence assessed by IFC in all instances, and are appropriate for the analysis of data from this vaccine trial. One of these methods also has the advantage of allowing for variable pool size. However, further research is needed to develop a method that will simultaneously account for variation in pool size and in test sensitivity and specificity.     

Evaluation of the potential suitability of guide dog candidates by continuous observation during training

Periodic monitoring of the training of prospective guide dogs for the blind was evaluated to determine if the monitoring is useful in gauging the potential suitability of guide dogs. We selected 8 dogs as test dogs on the basis of their medical check and pretraining evaluation. Beginning with day 1 of training, we monitored their progress every 2 weeks for 12 weeks. The evaluation was designed to assess task performance, stress, excitement, and concentration for the task. We set the test course in a residential district, but in an area that was not used for daily training. In some variables, such as tail position, duration of distraction, and effect of the training break, there were some differences between a dog that successfully completed guide training and dogs that did not.The number of stress reactions was significantly different between successful and unsuccessful dogs. Only 1 dog out of the 8 observed became a guide dog; however, the present study suggests that it is possible to detect some traits in the early stages of training that determine whether or not a dog successfully becomes a guide dog.     

Genetic differences in the frequency of the hinge variants of porcine IgA is breed dependent

The distribution of the IgA(a) and IgA(b) alleles of porcine IgA in over 160 randomly-selected animals revealed an abundance of heterozygotes but only two b/b homozygotes. Since the IgA(b) allotype is a splice site mutant lacking two-thirds of the hinge, this study tests the hypothesis that pigs with this genotype may be at a selective disadvantage while heterozygous individuals may be at some advantage.This hypothesis was tested by collecting data on 374 animals of known breed and often parentage. We show here that when breed was not considered, young animals of known parentage had genotypic frequencies identical to that expected for Mendelian alleles but that a/b heterozygotes were overrepresented in adults. However, when analyzed with regard to breed, a very strong association between breed and the frequency of the IgA(a) and IgA(b) alleles was discovered. Meishan and NIH minipigs were homozygous for IgA while heterozygotes predominated in Berkshire, Chester White, Durocs, Hampshire and Landrace. Animals homozygous for IgA(b) were best represented in the White Cross line. We show here that this very strong breed dependency of IgA allotypy in swine can produce a sample bias that can explain why only two b/b homozygotes (1.3%) were found in the 160 randomly-selected samples since the original samples came from primarily Landrace and Yorkshire animals. The expected frequency of b/b homozygotes in these breeds would be <3%. Thus, the data presented here reject the hypothesis that swine homozygous for a trait that results in loss of two-thirds of the IgA hinge, are selected against and that heterozygotes are positively selected. Rather, the study shows that IgA(a) and IgA(b) appear to be simple, breed-dependent allotypic markers.     

Reliability of two 2,400-m time-trial protocols for assessing performance of Standardbred racehorses

OBJECTIVE: To evaluate the reliability of 2 time-trial protocols, 1 that involved use of a pacemaker and 1 that did not, for assessing performance of Standardbred racehorses. ANIMALS: 3- to 7-year-old Standardbred maiden pacers. PROCEDURE: 11 Standardbred pacers were used to determine the reliability of a time-trial protocol that involved use of a galloping pacemaker. All tests were performed by a single driver. Horses were paced for an initial 1,600 m then raced and timed for the final 800 m. They were retested 9 days later. Twenty-two horses were used to determine the reliability of a time-trial protocol that did not involve use of a pacemaker. All tests were performed by a second driver. Horses were paced for the first 1,200 m then raced and timed for the final 1,200 m. They were retested 3 and 8 days later. RESULTS: Reliability of performance time, expressed as the coefficient of variation (ie, the typical percentage variation in a horse's time between trials), was similar for the 2 protocols (1.0% and 1.3%, respectively). CONCLUSIONS: The small variations in performance times for the 2 time-trial protocols were similar to those of the best comparable laboratory and field tests of human and equine performance. Both protocols would be suitable for investigating factors affecting performance of Standardbred racehorses.     

Pharmacological aspects of bunamidine dosing of dogs

Extract

No doubt you would all be delighted to note when Mr MacIntyre opened this conference that our Minister of Lands is well aware of the economic loss resulting from disease in animals. He estimated the national loss for 1969 to be between $110 and $130 million. Now, about 5% of this loss can be attributed to hydatid disease. We should be thankful that man is a less attractive secondary host for Echinococcus granulosus than is the sheep, because hydatids is a horrible disease which can still be fatal. It affects some lives as well as many purses. Moreover, hydatid disease is very much our problem in that most of the countries that have better facilities for re-search in this field have little incentive for entering it.     

Identification and Management of Critical Control Points in the Cow-Calf Enterprise for Achieving and Maintaining Consistency and Low Cost of Production: Summary of Integrated Resource Management-Standardized Performance Analysis Results

Integrated Resource Management-Standardized Performance Analysis (IRM-SPA) for fiscal yr 1995 was completed for 10 commercial cow-calf operations in southwestern Colorado. The ranches varied in size but operated in consistent production environments. Production and financial measures were examined and compared between operations. These included reproductive performance, weaning performance, and financial and economic costs for feed, grazing, and operating cost. Previous to a similar baseline analysis for fiscal yr 1994, the producers were not completely aware of the actual cost of production for their respective operations. The results of the analysis show that 7 out of the 10 operations had financial break-even values that were higher than the market price in the fall of 1995. Examples are provided for how a management tool like IRM-SPA can be used to identify critical control points for lowering costs in the cow-calf enterprise. IRM-SPA provides baseline data that can provide a starting point for monitoring progress of an individual operation, and it can serve a comparison with other operations within a region, production system, or the entire country, as shown in the presentation of these results. More importantly, it measures the cost per unit of production, which is an important variable that every cow-calf producer whose goals include continuing to participate in the beef production chain should know.     

The use of porcine small intestinal submucosa for the repair of full-thickness corneal defects in dogs, cats and horses

OBJECTIVE: To evaluate the efficacy of using a porcine small intestinal submucosa (SIS) graft covered by a conjunctival flap for the surgical repair of full-thickness corneal wounds in dogs, cats and horses. PROCEDURE: All records dating from August 1999 to February 2003 from Purdue University Veterinary Teaching Hospital of patients that had undergone ophthalmic surgical procedures and received a SIS corneal graft for a full-thickness lesion were reviewed. Fifteen cases were identified including six dogs, two cats and seven horses. Requirements for inclusion in this study were that SIS was used as a corneal graft in a full-thickness corneal defect and that the graft was completely covered with a conjunctival flap. RESULTS: Of the 15 cases, one canine patient had received SIS following removal of an epibulbar melanocytoma. The remaining five canine patients had undergone this surgical procedure for the repair of corneal perforation. The two feline patients had been presented for corneal perforation following chronic ulceration. One equine patient had been presented for a deep melting ulcer, three for stromal corneal abscesses, and three for corneal perforations. Complications encountered postoperatively included aqueous leakage, conjunctival flap dehiscence, synechia, cataract and fibrin in the anterior chamber. Fourteen out of 15 patients were visual at the final re-evaluation. CONCLUSION: SIS is an inexpensive, easy-to-handle biomaterial that appears to be suitable for the repair of full-thickness corneal wounds in dogs, cats and horses. Results of our study support the conclusion that this relatively new product is an effective alternative to traditional implantation materials utilized in veterinary ophthalmology.     

论社会主义的科学性与价值性的统一——兼评民主社会主义伦理价值观

民主社会主义认为社会主义具有“自由、平等、互助”等价值，因此，社会主义取代资本主义是人们一种道德追求，是道德力量使然，社会主义的实现，不具有历史必然性和规律性。唯物史观则认为，社会主义是科学性与价值性的统一，前者是后者的前提，规定着后者实现程度和速度，后者是前者的必然要求，并为前者提供精神动因。中国特色社会主义与民主社会主义存在原则区别，那种认为只有民主社会主义才能发展中国的论调是荒谬的。     

Relationship of equine housing to large airway inflammation

The pasture, as compared to stall confinement, has been considered a more desirable environment for maintaining the health of the respiratory system in the horse. This conclusion is based on reports which showed that ventilation in most barns was generally poor, and that horses bedded on straw and fed hay were exposed to many forms of respirable debris. In this study, six normal horses were evaluated for evidence of airway mucosal inflammation after being housed on pasture or stabled in a barn for one month. The response of the horses' airways was measured by assigning scores for the degree of tracheal mucosal secretions that were observed by endoscopic visualization. Cytological examination of transtracheal wash secretions was also performed, as well as histologic evaluation of tracheobronchial tissues obtained by a transendoscopic epithelial biopsy technique. Samples were collected at three time points; the initial collection occurred after the horses were housed on pasture for one month. The horses were subsequently moved to a barn for an equal length of time and samples were obtained at the end of this period. The horses were then returned to their original pasture and final sampling was performed after they were housed in this environment for two months. There were no significant changes in any of the parameters evaluated, regardless of the environment in which the horses were maintained. These findings indicate that housing horses in a barn for four weeks does not cause tracheobronchial mucosal inflammation in a manner that could be detected using the methods employed in this study.     

Transformation of Actinobacillus pleuropneumoniae and analysis of R factors by electroporation

An efficient method for DNA transfer is essential for the genetic manipulation of any organism. Such a capacity will be required for the genetic analysis of Actinobacillus pleuropneumoniae as a swine pathogen, as well as for its manipulation for vaccination purposes. For this reason, the use of electroporation as a means of plasmid DNA introduction into this species was examined. The multiple antibiotic-resistant strain 80-8141 of Actinobacillus pleuropneumoniae harbors 3 plasmids: pYG10, pYG15, and pYG12 of 5.0, 2.7, and 2.5 kb, respectively. Electroporation of A pleuropneumoniae strain 4074 with a plasmid extract of strain 80-8141 showed that pYG10 encodes chloramphenicol resistance and that pYG12 encodes ampicillin resistance. Electrical pulse conditions for efficient electroporation of strain 4074 were examined by use of pYG10 DNA isolated from a 4074 transformant. Efficiency, expressed as transformants per microgram of plasmid DNA, increased directly with pulse amplitude. However, high efficiencies were only observed in a narrow window of pulse duration (tau = 12 to 22 ms at 6.25 kV/cm). Longer pulse durations resulted in cell death. Electroporation efficiencies increased with cell density. Yield of transformants increased directly with DNA concentration. Results indicate that electroporation can be used to efficiently transform A pleuropneumoniae and that pYG10 and pYG12 are suitable plasmid vectors for use in the genetic manipulation of this organism.     

南京地区犬细小病毒基因型鉴定

为调查南京地区犬细小病毒(canine parvovirus,CPV)基因型分布情况,采集南京市某宠物医院2012-2019年犬细小病毒病患犬粪便43份作为检测病料,通过PCR扩增犬细小病毒VP2基因片段,并将扩增产物测序,分析CPV基因型.结果显示,43份病料皆扩增出目的片段,经测序后使用MegAlign软件与Gen...