Factors associated with the development of equine degenerative myeloencephalopathy

A case-control study was done to identify factors associated with the development of equine degenerative myeloencephalopathy (EDM). Questionnaires were mailed to the owners of 146 horses admitted to the New York State College of Veterinary Medicine between November 1978 and June 1987 and diagnosed as having EDM by histologic examination. Questionnaires also were sent to owners of 402 clinically normal horses admitted to the college during the same period. Data were compared between the EDM-affected and control groups (56 and 179 questionnaires returned, respectively). Risk factors identified included the use of insecticide applied to foals, exposure of foals to wood preservatives, and foals frequently spending time on dirt lots while outside. Foals spending time outside on green pastures was a protective factor. Foals from dams that had had an EDM-affected foal were at higher risk of developing EDM than were foals from other dams.     

Toxicity of synthetic piperonyl compounds to leaf-cutting ants and their symbiotic fungus

The development of Leucoagaricus gongylophorus, the fungus cultured by the leaf-cutting ant Atta sexdens was inhibited in vitro by synthetic compounds containing the piperonyl group. In addition, worker ants that were fed daily on an artificial diet to which these compounds were added had a higher mortality rate than the controls. The inhibition of the fungal growth increased with the size of the carbon side chain ranging from C1 through C8 and decreasing thereafter. 1-(3,4-Methylenedioxybenzyloxy)octane (compound 5) was the most active compound and inhibited the fungal development by 80% at a concentration of 15 micrograms ml-1. With worker ants the toxic effects started with compound 5 and increased with the number of carbons in the side chain. Thus, for the same concentration (100 micrograms ml-1) the mortality rates observed after 8 days of diet ingestion were 82%, 66% and 42%, for 1-(3,4-methylenedioxybenzyloxy)decane, 1-(3,4-methylenedioxybenzyloxy)dodecane and compound 5, respectively, whereas with commercial piperonyl butoxide the mortality was 68%. The latter compound, which is known as a synergist insecticide, was as inhibitory to the symbiotic fungus as the synthetic compound 5. The possibility of controlling these insects in the future using compounds that can target simultaneously both organisms is discussed.     

Host--parasite relationship in cysticercosis: immunologic study in different compartments of the host

Cysticerci parasitize several mammalian species, including man, in which the parasitic disease shows unique characteristics since cysticerci are established mainly in immunologically privileged sites and can survive for many years. The study of the human immune response to cysticerci is helpful in diagnosis and could perhaps also aid in preventing or curing the disease. Anti-cysticercus IgG can be detected in serum and cerebrospinal fluid (CSF) of almost all patients with neurocysticercosis, by the enzyme-linked immunosorbent assay (ELISA); antibodies of the other classes are found less frequently. Antibodies react with up to eight Taenia solium cysticercus antigens, mainly with antigen B. This antigen has an affinity for collagen and is not commonly found in the CSF. It could therefore be participating in vasculitic processes spotted in the brain of neurocysticercotic patients. Immunoglobulins are also identified on the surface of the parasites: IgG is detected on parasites obtained from various tissues; IgM, IgA and IgE mostly on extracerebral cysticerci. We discuss the possibility of extraneural cysticerci being destroyed by the immune response of the host whereas natural aging may cause brain cysticerci death.     

Knots detection in wood using microwaves

This work describes a microwave technique used to generate and process data on knots in wood prior to processing. The experimental design was a simple system composed of a microwave emitter and receiver used to scan the wood samples with knots. Signals were calibrated and amplified, and then a data storage and graphic visualization were performed. A PCL-711 data acquisition card was used in conjunction with data acquisition software. The preliminary results obtained for the studied wood samples were viewed in 2- and 3-dimensional graphics, showing a strong relation with the visual inspection of the samples.     

Association of Gallbladder Mucocele Histologic Diagnosis with Selected Drug Use in Dogs: A Matched Case‐Control Study

Background

The cause of gallbladder mucocele (GBM) formation in dogs currently is unknown. Many available drugs represent a newer generation of xenobiotics that may predispose dogs to GBM formation.

Objective

To determine if there is an association between the histologic diagnosis of GBM in dogs and administration of selected drugs.

Animals

Eighty‐one dogs with a histologic diagnosis of GBM and 162 breed, age, and admission date‐matched control dogs from a single referral institution.

Methods

Medical records of dogs with GBM and control dogs from 2001 to 2011 were reviewed. Owner verification of drug history was sought by a standard questionnaire. Reported use of heartworm, flea, and tick preventatives as well as nonsteroidal anti‐inflammatory drugs, analgesics, corticosteroids, or medications for treatment of osteoarthritis was recorded.

Results

Dogs with GBM were 2.2 times as likely to have had reported use of thyroxine (as a proxy for the diagnosis of hypothyroidism) as control dogs (95% confidence interval [CI], 0.949–5.051), 3.6 times as likely to have had reported treatment for Cushing''s disease (95% CI, 1.228–10.612), and 2.3 times as likely to have had reported use of products containing imidacloprid (95% CI, 1.094–4.723). Analysis of a data subset containing only Shetland sheepdogs (23 GBM and 46 control) indicated that Shetland sheepdogs with GBM formation were 9.3 times as likely to have had reported use of imidacloprid as were control Shetland sheepdogs (95% CI, 1.103–78.239).

Conclusions and Clinical Importance

This study provides evidence for an association between selected drug use and GBM formation in dogs. A larger epidemiologic study of Shetland sheepdogs with GBM formation and exposure to imidacloprid is warranted.     

Starch levels on performance,milk composition and energy balance of lactating dairy cows

The objective of this experiment was to evaluate the effects of starch levels in diets with the replacement of citrus pulp for corn on milk yield, milk composition, and energy balance of lactating dairy cows. Twenty-eight multiparous Holstein cows were used in seven 4?×?4 Latin squares conducted concurrently, and each experimental period consisted of 20 days (16 days for adaptation and 4 days for sampling). The experimental treatments comprised four starch levels: 15, 20, 25, and 30 % in the diet. The dry matter intake increased linearly with increasing starch levels. The milk yield and 3.5 % fat-corrected milk yield showed quadratic response to increasing starch levels. The milk protein content and milk total solids content responded linearly to increasing starch levels. The feed efficiency, milk lactose content, milk urea nitrogen, plasma urea nitrogen, and plasma glucose concentration were not affected by starch levels. The estimated net energy for lactation (NE_L) intake increased linearly as the starch level was raised. Although the milk NE_L output per kilogram of milk was not affected by starch, the milk NE_L output daily responded quadratically to starch levels. In addition, the NE_L in body weight gain also responded quadratically to increasing starch levels. The efficiency of energy use for milk yield and the NE_L efficiency for production also responded quadratically to increasing starch levels. Diets for mid-lactating dairy cows producing around 30 kg/day of milk should be formulated to provide around 25 % starch to optimize performance.

     

Mimosa tenuiflora as a cause of malformations in ruminants in the northeastern Brazilian semiarid rangelands

Craniofacial anomalies, eye malformations, and permanent flexures of the forelimbs are common malformations seen in ruminants grazing semiarid rangelands of Northeastern Brazil. To investigate the cause of these malformations, we fed 2 suspected plants, Mimosa tenuiflora or Prosopis juliflora, to groups of 4 pregnant goats each. Fresh green M. tenuiflora was collected daily and fed ad libitum to 4 goats in group 1 throughout pregnancy. This treatment group also received a supplemental feed concentrate equivalent to 1% body weight. Four goats in group 2 received a ration with 70% of P. juliflora pods and 30% hay throughout pregnancy. Four control goats were fed supplemental feed concentrate (1% body weight) and hay ad libitum throughout pregnancy. Goats treated with P. juliflora pods and the control goats delivered 9 normal kids. The four goats that were fed M. tenuiflora during pregnancy delivered 4 kids, 3 of which had abnormalities similar to those observed in field cases, including cleft lip, unilateral corneal opacity, ocular bilateral dermoids, buphthalmos with a cloudy brownish appearance of the anterior chamber due to an iridal cyst, and segmental stenosis of the colon. Malformations induced experimentally by M. tenuiflora were similar to those observed in field cases, suggesting that M. tenuiflora is a cause of the field cases observed in the Brazilian semiarid rangelands.     

Virulence and pCM1 plasmid carriage are related to BOX-PCR fingerprint type in strains of Clavibacter michiganensis subsp. michiganensis that cause bacterial wilt and canker of tomato in Argentina

Clavibacter michiganensis subsp. michiganensis (Cmm) causes bacterial wilt and canker in tomato, producing important economic losses worldwide. Its virulence has been related to several putative virulence factors present on a chromosomal pathogenicity island and on plasmids pCM1 and pCM2, in strain NCPPB382. We genotypically characterized a collection of Cmm isolates from the main greenhouse tomato-producing areas of Argentina by BOX-PCR fingerprinting and screened for the presence of genes and plasmids involved in pathogenicity by PCR. In addition, we evaluated in vitro cellulolytic activity and virulence in planta of selected strains. BOX-PCR fingerprinting clustered strains into four groups. Group II was dominant and included the most virulent strains, while Group III was the smallest and had the least virulent strains. All local strains exhibited similar cellulolytic activity. Most of the examined strains carry two plasmids of similar size to those of NCPPB382, although there were strains with one or three plasmids. By PCR amplification of repA, pCM1 was detected only in strains belonging to Group III, which includes local strains closely related to reference strain NCPPB382. All analysed pathogenicity genes were widespread among strains, and so in strains belonging to Groups I and II, celA found on pCM1 in NCPPB382 could be found in the chromosome or in plasmids other than pCM1. This study contributes to a better understanding of the diversity of Cmm genetic profiles and virulence of strains present in Argentina. Such information could be useful for the selection of strains for screening of host resistance and development of resistant tomato varieties.     

High allozyme variation and genetic similarity of two populations of commercial penaeids, Penaeus brevirostris (Kingsley) and P. vannamei (Boone), from the Gulf of California

Genetic resources assessment is considered as the starting point for population management in both fisheries and aquaculture. In this study, we have obtained genetic variability measures of two commercial penaeid shrimp species, Penaeus brevirostris (Kingsley) and P. vannamei (Boone), from the Gulf of California by means of starch electrophoresis analysis of 16 enzymatic systems, plus total protein. Thirty-two loci were resolved, which revealed polymorphism values (P₉₅) of 15.63% in P. brevirostris and 25.00% in P. vannamei. Unbiased expected heterozygosity (H_e) was 0.076 and 0.105 respectively. These are high genetic variability figures, taking into account the previously low genetic variability, assessed by means of allozyme variation, reported in several penaeid species around the world. Nei’s genetic similarity between the two species is 0.891.     

Ammonia‐, Sodium Chloride‐, and Calcium Sulfate‐induced Changes in the Stress Responses of Jundiá, Rhamdia quelen,Juveniles

Salt (NaCl) and gypsum (CaSO₄) are used as water additives to mitigate fish stress and improve specimen survival. High stocking densities and the transportation of fish can increase aqueous ammonia, which can, in turn, alter fish cortisol secretion. The objectives of this study were to assess the effects of salt, gypsum, and aqueous ammonia on some stress‐induced physiological responses of jundiá, Rhamdia quelen, juveniles induced by captivity and handling, and to determine the lethal ammonia concentration for this species. Jundiá juveniles were subjected to the following five treatments: water only, water + ammonia (0.4 mg/L), water + NH₃ + NaCl (6 g/L), water + NH₃ + gypsum (150 mg/L), and water + NH₃ + NaCl + gypsum. Blood samples were taken after intervals of 1, 5, 24, and 96 h, and the concentrations of cortisol, glucose, chloride, ammonia, and hematocrit were determined. The NH₃ LC₅₀ value after 96 h of exposure (LC_50?96h) was measured to be 1.9 mg/L NH₃. Either salt or gypsum reduced both cortisol and glucose levels during most of the experimental period, but the combination of both reduced these levels even further. The combined use of NaCl and CaSO₄ demonstrates a synergic effect on mitigating stress responses induced by handling and aqueous ammonia in jundiá juveniles.