Expression of the “<Emphasis Type="Italic">glanded-plant</Emphasis> and <Emphasis Type="Italic">glandless-seed</Emphasis>” trait of Australian diploid cottons in different genetic backgrounds

The expression of the “glanded-plant and glandless-seed” trait was assessed using High Performance Liquid Chromatography (HPLC) analysis methods in different Gossypium hybrids obtained by crossing Australian diploid cottons and various diploid and tetraploid species. Significant variation in the gossypol content in the seed was observed among the analyzed genotypes. HPLC data demonstrated that the gossypol synthesis repression mechanism in the Australian diploid species belonging to C and G genomes was dominant but did not confirm its preferential functioning against A genome species bearing GL₂ locus. About 10% of the produced seeds had total gossypol content lower than the limit imposed by the World Health Organisation (600 ppm) for the use of cotton flour in food and feed. HPLC analysis of the terpenoids aldehyde (TA) contents in the aerial parts of the hybrids showed important qualitative and quantitative variability. This result could indicate a certain separation between pigment gland morphogenesis and terpenoid synthesis mechanisms in cotton.     

Factors Affecting the Readiness and Preparation of Replacement Heifers in Tropical Breeding Environments

The future of beef cattle production in tropical regions is uncertain because of land tenure concerns, threatening the survival of extensive management programmes in these areas of the world. The need to intensify production systems will inevitably lead to changes in the management of replacement animals in existing herds. The present review underlines the main constraints, which in the past could be resolved by the sheer numbers of animals present in beef cattle operations, with replacements reliant only on finding enough heifers to substitute the adult females destined for culling. This scenario is rapidly changing as beef cattle units in tropical regions subdivide to share out the land between as many farmers as possible. Consequently, issues such as the efforts needed to manage the pregnant cow, particularly her nutritional status and its effect on the new‐born calf, the future replacement heifer growing in the presence of the dam, weaning management and procedures required before a heifer can be introduced into a breeding programme, need to be adequately and efficiently addressed by farmers in tropical regions.     

Influence of Cysteamine on In Vitro Maturation, In Vitro and In Vivo Fertilization of Equine Oocytes

The effect of cysteamine on in vitro nuclear and cytoplasmic maturation of equine oocytes collected by transvaginal ultrasound guided follicular aspiration was assessed. Oocytes were matured in vitro with (cysteamine group) or without (control group) cysteamine. The nuclear stage after DNA Hoechst staining, penetration rates after two different in vitro fertilization (IVF) techniques (IVF media with ionophore and Hepes buffer with heparin) and the embryo yield following oocyte intra-oviductal transfer were used as a criterion for assessing nuclear and cytoplasmic maturation, respectively. Contrary to the data described in other domestic species, there was no effect of cysteamine on in vitro nuclear maturation, IVF or in vivo embryonic development under our conditions. Ovum pick up yields (52%) and maturation rates (control group: 47% and cysteamine group: 55%) were similar to those previously reported. From 57 oocytes transferred to the oviduct in each group, the number of embryos collected was 10 (17%) in the control group and five in the cysteamine group (9%). Those two percentages were not statistically different (p > 0.05). No effect of IVF technique was seen on the success rate (6%) in each group.     

Comparison of Multistage Versus One-Stage Destabilization of a Type II External Fixator Used to Stabilize an Oblique Tibial Osteotomy in Dogs

OBJECTIVE: To compare the biomechanical effects of multistage versus one-stage destabilization of a type II external skeletal fixator (ESF) used to stabilize an oblique unstable tibial osteotomy in dogs. STUDY DESIGN: In vitro, in vivo, and ex vivo experimental study. ANIMAL POPULATION: Twelve healthy adult dogs. METHODS: The biomechanical characteristics of the type II ESF used in this study were determined. This fixator was applied to both tibiae of two groups of 6 dogs to stabilize a 2-mm-wide oblique osteotomy. One fixator on each dog remained unchanged throughout the 11-week study (control group). The fixator on the opposite limb was destabilized late and acutely in one group of dogs (single-stage) and early and progressively in the other (multistage). Clinical examination, radiographic examination, and force-plate analysis were used to evaluate the results. All dogs were euthanatized at 11 weeks. All tibiae were scanned to determine the cross-sectional area of the callus in the center of the osteotomy and subjected to biomechanical tests to determine mean pull-out strength of pins and callus strength and stiffness. RESULTS: Stiffness of the type II ESF used in this study was 578 N/mm in axial compression, 0.767 Nm/deg in torsion, 261 N/mm in medio-lateral bending, and 25 N/mm in cranio-caudal bending. Peak vertical forces of the hindlimbs were significantly lower at 2.5 and 5 weeks than before surgery. Peak vertical forces of the hindlimbs did not change before and after destabilization. No significant differences could be detected between the two destabilization sequences or between all control tibiae and pooled destabilized tibiae with regards to radiographic evaluation of the healing osteotomy, cross-sectional periosteal callus area, mean pull-out strength of transfixation pins, callus strength, and callus stiffness. CONCLUSIONS AND CLINICAL RELEVANCE: Bone healing of unstable osteotomies stabilized with a type II ESF is not significantly enhanced by staged destabilization of the fixation as performed in this study.     

Analysis of landscape patterns in coastal wetlands of Galveston Bay,Texas (USA)

High productivity and accessibility have made coastal wetlands attractive sites for human settlements. This study analyzed the patterns of wetland landscapes in Galveston Bay, Texas, USA. The first objective of the study was to describe the relationships between the fractal dimension of wetland boundaries and those factors which affect the wetland landscapes (e.g., land use, type of vegetation, size, location, and level of human disturbance). The second objective was to construct a historical database to contrast wetland areas which had experienced different levels of disturbance between 1956 and 1989. The fractal dimension, a measure of how much of the geographical space is filled by boundaries, was measured by the perimeter-area method. The fractal dimension of wetlands was significantly affected by land use, type of vegetation, size, and level of anthropogenic disturbance. In addition, increasing the size of buffers around roads did not significantly affect the fractal dimension of wetlands. Landscape indices, such as fractal dimension, dominance, and diversity, were used to characterize spatial heterogeneity in the historical database. Lake Stephenson, an area of low anthropogenic disturbance, experienced no changes in wetland composition and abundance over time. Anahuac, an area of medium disturbance, experienced changes in both wetland composition and abundance. Texas City, an area of high disturbance, experienced a change in wetland composition. These differences can be associated with the type and level of disturbance present; however, more evidence is needed to determine whether certain landscape patterns have stable, intrinsic properties which allow persistence in the face of disturbance. These results will be informative to resource managers determining how wetlands can be managed as natural resources and nature reserves.     

Canine Bladder and Urethral Tumors: A Retrospective Study of 115 Cases (1980–1985)

One hundred and fifteen dogs with neoplasms of the lower urinary tract (bladder and/or urethra) were retrospectively evaluated at five referral institutions participating in ongoing studies by the Veterinary Cooperative Oncology Group. Most tumors were malignant (97%) and of epithelial origin (97%). Lower urinary tract tumors were more common in older dogs weighing greater than 10 kg. The following significant (P less than 0.05) statistical associations were found using the University of Guelph hospital population as control; there was no sex predisposition although the female:male ratio was 1.95:1. Neutered dogs were predisposed as were Airedale Terriers, Beagles, and Scottish Terriers, whereas German Shepherds were significantly under-represented among dogs with lower urinary tract tumors. These statistical associations should be interpreted cautiously because of possible demographic differences in hospital populations among the University of Guelph and other cooperating institutions. There were no significant correlations between age, gender, weight, breed, response to therapy, and survival time. Clinical signs were indicative of lower urinary tract disease and included hematuria, stranguria, and pollakiuria. The laboratory data were nonspecific except for urinalysis test results. Hematuria and inflammatory urinary sediments were most commonly reported; neoplastic cells were identified in the urine sediment of 30% of dogs with lower urinary tract tumors. Contrast cystography was a useful noninvasive diagnostic method since 96% of the dogs had a mass or filling defect in the lower urinary tract demonstrated by this technique.(ABSTRACT TRUNCATED AT 250 WORDS)     

Prevalence of anthelmintic resistant cyathostomes on horse farms

OBJECTIVE: To determine prevalence of anthelmintic resistance in cyathostome nematodes of horses in the southern United States. DESIGN: Cross-sectional study. ANIMALS: 786 horses on 44 farms and stables in Georgia, South Carolina, Florida, Kentucky, and Louisiana. PROCEDURE: Fecal egg count (FEC) reduction tests were performed on 44 large farms and stables. Horses on each farm were treated with an oral paste formulation of fenbendazole, oxibendazole, pyrantel pamoate, or ivermectin at recommended label dosages. A mixed linear model was fitted to the percentage reduction in FEC, accounting for differences among farms, states, ages, treatments, and treatment by state interactions. RESULTS: By use of a conservative measure of resistance (< 80% reduction), the percentage of farms with anthelmintic-resistant cyathostomes was 97.7%, 0%, 53.5%, and 40.5% for fenbendazole, ivermectin, oxibendazole, and pyrantel pamoate, respectively. Mean percentage reductions in FEC for all farms were 24.8%, 99.9%, 73.8%, and 78.6% for fenbendazole, ivermectin, oxibendazole, and pyrantel pamoate, respectively. Pairwise contrasts between states for each treatment revealed that in almost all instances, there were no significant differences in results between states. CONCLUSIONS AND CLINICAL RELEVANCE: The prevalence of resistance found in this study was higher than that reported previously, suggesting that anthelmintic resistance in equine cyathostomes is becoming a major problem. Furthermore, data from these 5 southern states, which are geographically and physiographically distinct, were remarkably similar. This suggests that drug resistance in cyathostomes is highly prevalent throughout the entire southern United States and probably nationwide.     

A Combination of Baiting and Different PCR Formats, Including Measurement of Real-Time Quantitative Fluorescence, For the Detection of Phytophthora fragariae in Strawberry Plants

Phytophthora fragariae, the cause of strawberry red stele disease, is a quarantine pathogen in Europe. Detecting low levels of infection requires sensitive and specific methods. In the past, Dutch and English inspection services have used bait plants to test strawberry propagation stocks destined for export. Increasingly though, PCR is being incorporated into these testing procedures in an effort to increase sensitivity and speed. Various combinations of baiting and PCR assays were compared with existing testing procedures. Water and root samples from the bait test were screened by nested PCR and the PCR amplicon was detected by several methods, including fluorescent labelled probes (TaqMan and Molecular Beacon). PCR amplification was monitored in real-time and semi-quantitative detection was possible. Because PCR reactions are sensitive to inhibitors present in extracted DNA samples, an internal control containing the primer sequences specific for P. fragariae was developed to avoid false negatives.     

Use of magnetic motor-evoked potentials in horses with bilateral hind limb ataxia

OBJECTIVE: To determine the usefulness of magnetic motor-evoked potentials (MMEPs) for assessing the integrity of the cervical, thoracic, and thoracolumbar spinal cord in horses with bilateral hind limb ataxia. ANIMALS: 9 horses and 1 donkey with bilateral hind limb ataxia of various degrees. PROCEDURE: The motor cortex was stimulated magnetically, and MMEPs were recorded bilaterally from the extensor carpi radialis and cranial tibial muscles. RESULTS: In 5 horses and 1 donkey, MMEPs with normal onset latencies and peak-to-peak amplitude were recorded from the extensor carpi radialis muscles, whereas abnormal onset latencies and peak-to-peak amplitudes were recorded from the cranial tibial muscles. In these animals, a spinal cord lesion in the thoracic or thoracolumbar segments was suspected. In 4 horses, onset latencies and peak-to-peak amplitude of MMEPs recorded from the extensor carpi radialis and cranial tibial muscles were abnormal. In these horses, a cervical spinal cord lesion was suspected. CONCLUSIONS AND CLINICAL RELEVANCE: Transcranial magnetic stimulation can be considered a valuable diagnostic tool for assessing the integrity of the spinal cord, and MMEPs may be used for differentiating thoracic or thoracolumbar spinal cord lesions from mild cervical spinal cord lesions that cause ataxia in the hind limbs only.