The introduction of expert systems in animal husbandry

The intensive nature of modern animal husbandry has changed the environmental conditions, so that protection against diseases, especially those caused by secondary pathogenic organisms, becomes an increasing concern. Production inefficiencies become more and more important. Because of their complex nature, many associated problems cannot be solved by farmers alone. With the introduction of information technology in the form of expert systems, new possibilities emerge for maximal productivity and animal health. Expert systems are a new type of computer programmes which are able to handle problems in limited domains at an expert level, using expert knowledge and reasoning processes, within strictly defined problem limits. Expert systems as they presently exist have the following components: a knowledge base (rule- and data-base), inference engine (deductive mechanism), user-interface (explanatory facilities, etc.). The application of knowledge engineering in animal husbandry may result in improvements in the general health and productivity of the herd and the financial returns of the farm, derived from the improved managerial control. At the same time the use of knowledge engineering may lead to greater understanding of the various epidemiological factors that influence farm results, either positively or negatively.     

Infiltrating Foxp3+ Regulatory T cells and Histopathological Features in Canine Classical and Spermatocytic Seminomas

In humans, regulatory T (T reg) cells are known to play a critical role in both the regulation of immune homoeostasis and the progression of cancer. However, there is little information about the identification, characterization and the function of T reg cells in canine tumours. We identified T reg cells in 28 canine seminoma samples using a Forkhead box P3 (Foxp3) antibody and investigated the relationship between T reg cell infiltration and histopathological features of classical and spermatocytic seminomas (SE and SS, respectively). The Foxp3 protein showed nuclear immunostaining in infiltrating lymphocytes, and Foxp3+ cells were diffused or focally distributed in seminoma tissues. Foxp3+ cells were frequently present in the SS histotype, in seminomas that showed no evidence of tumour cell invasion into the vessels and in seminomas showing a diffuse growth pattern with three cell types. Neither the SE/SS histotype nor the histopathological features of the tumour correlated with Foxp3+ cell counts. These results indicate that Foxp3+ T reg cells may be associated with a less malignant histological phenotype or may not play a critical role in the immune response of canine seminomas. Moreover, Foxp3+ T reg cells may be associated with SS seminoma, but further studies, involving a larger number of samples, are required to better understand whether these cells play a critical role in the immune response in canine seminomas. This is the first report to demonstrate the characteristics of T reg cell infiltration in canine seminoma.     

Effect of Dimethyl Sulfoxide on Cell Cycle Synchronization of Goldfish Caudal Fin Derived Fibroblasts Cells

Several studies have previously been conducted regarding cell cycle synchronization in mammalian somatic cells. However, limited work has been performed on the control of cell cycle stages in the somatic cells of fish. The aim of this study was to determine the cell cycle arresting effects of several dimethyl sulfoxide (DMSO) concentrations for different times on different cell cycle stages of goldfish caudal fin‐derived fibroblasts. Results demonstrated that the cycling cells or control group (68.29%) yields significantly higher (p < 0.05) arrest in G0/G1 phase compared with the group treated for 24 h with different concentrations (0.5%, 1.0% or 1.5%) of DMSO (64.88%, 65.70%, 64.22% respectively). The cell cycle synchronization in the treatment of cells with 1.0% DMSO at 48 h (81.14%) was significantly higher than that in the groups treated for 24 h (76.82%) and the control group (77.90%). Observations showed that treatment of DMSO resulted in an increase in the proportion of cells at G0/G1 phase for 48 h of culture. However, high levels of apoptotic cells can be detected after 48 h of culture treated with 1% concentration of DMSO.     

Intravenous catheterisation of conventional pigs without application of antimicrobial agents

In six experiments 43 castrated male conventional pigs weighing 25-41 kg were catheterised by inserting a cannula via the jugular vein into the cranal caval vein. The catheters were taped to the spinal neck region where the tap stops were located. Antimicrobial agents were not applied. One pig died 32 hour after surgery from Porcine Stress Syndrome. The catheters remained patent for at least nine days in 38 of the remaining 42 animals (90%). In two animals the catheter by mistake was not inserted into the jugular vein. Two animals got catheters with a one-way blockage four days after surgery. In these animals autopsy revealed thrombosis and phlebitis of the occluded vein and a valve-like thrombus at the tip of the catheters. In seven of the 43 pigs the effects of anaesthesia, surgery and catherisation were followed using rectal temperature and haematological and some blood biochemical parameters for nine days after the surgery. It is concluded that this catheterisation technique, without application of antimicrobial agents, can be used well for experimental infections and pharmacokinetic studies.     

Molecular Basis of Gene-for-Gene Specificity in Bacterial Speck Disease of Tomato

Transient expression of the Pseudomonas syringae avirulence gene avrPto in plant cells resulted in a Pto-dependent necrosis. The AvrPto avirulence protein was observed to interact directly with the Pto resistance protein in the yeast two-hybrid system. Mutations in the Pto and avrPto genes which reduce in vivo activity had parallel effects on association in the two-hybrid assay. These data suggest that during infection the pathogen delivers AvrPto into the plant host cell and that resistance is specified by direct interaction of Pto with AvrPto.     

Estimating the incidence of influenza-virus infections in Dutch weaned piglets using blood samples from a cross-sectional study

A cross-sectional study was carried out on 32 Dutch breeding herds to estimate the incidence of influenza-virus infections in piglets before the start of the finishing period, at the age of approximately 10 weeks. Longitudinal studies on two herds (8 and 10 litters, respectively) were done to obtain an average decay function for maternal antibodies.Each participating farm in the cross-sectional study was visited twice within 5 months; each time, blood samples were taken randomly from one compartment (a separate room with separate air flow) of 4-5-week-old piglets and one compartment of 8-9-week-old piglets. These blood samples (a total of 2598; 16-23 per compartment, depending on its size) were tested in a haemagglutination inhibition test for antibodies against influenza-virus subtypes H1 and H3. Samples from 8-9-week-old piglets from the first sampling period (n=660) were also tested in an IgM ELISA.For each individual herd and each influenza-virus subtype separately, the decay function derived from the longitudinal studies was used to calculate an expected seroprevalence in 8-9-week-old piglets, which was then compared to the observed seroprevalence. Depending on subtype and sampling period, between 10 and 15 of the 32 herds were suspected of virus circulation during the weaning period because the observed seroprevalence was significantly higher than the expected seroprevalence (P<0.05). In the first sampling period the IgM ELISA confirmed six of these outbreaks. However, due to the small window of detection of the IgM ELISA (compared to the length of the weaning period), it will always underestimate the number of infections. Infections in the first half of the weaning period will no longer be detectable because IgM antibodies have already disappeared.In individual pigs, an incidence of 16-17% was estimated for each subtype over a 4-week period between the age of 4-5 and 8-9 weeks. For each influenza subtype, 80% of the piglets will enter the finishing facilities without antibodies or with decaying maternal antibodies. These piglets may be susceptible to an infection with influenza virus.     

Identification of the DDAH2 Protein in Pig Reproductive Tract Mucus: A Putative Oestrus Detection Marker

Precisely detecting oestrus is important for artificial insemination. The aims of this study were to identify oestrus‐specific sow mucus proteins to determine the optimal time for artificial insemination. The proestrous‐ and oestrous‐stage mucus proteins were purified and analysed with proteomic tools such as two‐dimensional gel electrophoresis and matrix‐assisted laser desorption/ionization–time‐of‐flight analyses. Among the differentially expressed proteins, the dimethylarginine dimethylaminohydrolase 2 (DDAH2) protein showed a 3.6‐fold increase during the proestrous stage compared to that during the oestrous stage. A western immunoblot study revealed that two of three sow mucus samples clearly showed negative anti‐DDAH2 antibody activity during the oestrous stage. This study demonstrated that the pig DDAH2 mucus protein exists during the proestrous stage, but not during the oestrous stage, suggesting that mucus DDAH2 could be useful as an oestrus detection marker.