Influence of Acute Exercise on Serum Homocysteine in Horse

The effect of acute exercise on serum homocysteine (sHCy) concentration was examined in 10 horses; five Sella Italiana and five Thoroughbreds. All horses underwent standard training before the study (show jumping for Sella Italiana horses and gallop racing for Thoroughbreds). For the study, blood samples were taken at rest, immediately after exercise, and during a recovery period (30 and 60 minutes after exercise) by external jugular venipuncture. sHCy values were determined by high-performance liquid chromatography. Heart rate and blood lactate were monitored to quantify the workloads. In show jumpers, there was a significant effect of sampling time on sHCy (P < .01), which increased significantly after exercise as compared with at rest. In Thoroughbreds, no statistically significant differences were observed in sHCy over time (F_(3,12) = 0.89, P = .05). The baseline values of sHcy were higher in Thoroughbreds than in show jumpers (P < .0002). We infer that physical activity causes biochemical changes that can influence the metabolic pathway of homocysteine in show jumpers, whereas the absence of a significant effect of exercise in Thoroughbreds may reflect an adaptive response of the enzymatic antioxidant defense system.     

Cloning and tissues expression of the pig CYP1B1 and CYP2J34

Cytochrome P450 (CYP) 1B1 and CYP2J have been studied in various mammals, but not in pig. The sequences encoding pig CYP1B1 and CYP2J34 were isolated from liver cDNA by RACE and sequenced. The open reading frames of pig CYP1B1 showed a higher sequence homology to bovine 1B1 (89%) than to dog 1B1 (88%) or to human 1B1 (85%). On the other hand, the coding sequence of pig CYP2J34 showed a similar homology (83-85%) to CYP2J of these species. From the substrate recognition sites (SRS 1-6) analysis of the deduced proteins, it was found that the porcine CYP1B1, unlike CYP2J34, completely shared the six SRS with the bovine counterpart. RT-PCR analysis of CYP1B1 and CYP2J34 expression in ten porcine tissues revealed that CYP1B1 was principally expressed in adrenal gland, whereas CYP2J34 was predominantly expressed in small intestine. These results further support the pig as an useful model for human.     

The occurrence of Dirofilaria immitis in dogs in South Australia

Heart, lung and samples of blood from 230 dogs were examined for infections of filarial parasites. Dirofilaria immitis worms and microfilariae were detected in one dog. Blood samples from a further 1428 dogs were examined for microfilariae and 22 were found to be infected. Eighteen dogs were infected with D immitis microfilariae and four with Dipetolonema reconditum microfilariae. The histories were available for 18 of the dogs infected with heartworm and only seven dogs had not travelled outside South Australia. It was concluded that heartworm infection was endemic in South Australia but the apparent prevalence was only about 1%.     

Effect of eCG Superstimulation and Buserelin on Cumulus–Oocyte Complexes Recovery and Maturation in Llamas (Lama glama)

The aim of the present study was two fold. Experiment I: evaluate the effect of buserelin on llama's oocyte maturation after exogenous follicular activity suppression, followed by ovarian superstimulation with different doses of equine chorionic gonadotropin (eCG). Experiment II: compare the number of follicles aspirated and the number of cumulus–oocyte complexes (COCs) recovered according to different doses of eCG followed by buserelin. Experiment I consisted in a control group (without buserelin) and a treatment group (with buserelin), both subdivided according to eCG dose administered: A: 500 IU; B: 1000 IU; C: 1500 IU. The treatment group received a single i.v. dose of 8 μg of buserelin when two or more dominant follicles were found at ultrasound evaluation and 20 h later were subjected to surgery. In group A, 83% of the llamas did not respond to superstimulation. In groups B and C differences were observed between the control and the treatment groups for the degree of COCs maturation (p < 0.05). In experiment II animals were divided into two groups according to the eCG dose administered: 1000 and 1500 IU. Twenty hours before surgery females received a single i.v. dose of 8 μg of buserelin. Average number of follicles aspirated and COCs recovered was higher (p < 0.05) with the administration of 1500 IU of eCG. A larger number of expanded COCs were obtained from follicles ≥7 mm in diameter. We conclude that buserelin aids the recovery of a larger number of expanded COCs. Administration of 1500 IU of eCG produces a higher number of follicles for aspiration and number of COCs recovered.     

Evaluating the risk of the establishment of screwworm fly in Australia

Objective To investigate probabilities of establishment of screwworm fly throughout the year, for several locations around Australias coastline.
Methods A simulation model that predicts the spread and economic impact of an established screwworm fly population was modified to include stochastic survival functions, to investigate the risks of the pest actually establishing in this country. The effects of time of year, climate, vegetation and the number of incoming flies or larvae were investigated for four locations around Australia.
Results Analysis of variance identified a dominant three-way interaction between site, time, and the number of introduced flies. These probabilities are graphed.
Discussion In southern areas, as exemplified by Fremantle, the cold winters limit survival. A high probability of establishment exists year round in tropical regions, except in areas around the Gulf of Carpentaria and in the Northern Territory where dry weather mid-year would limit survival. Despite these comparatively lower risks, there were no areas or times where reductions in quarantine efforts could be justified.     

Advances in pasture management for animal productivity and health

A wide range of management techniques is available to enhance quantity and quality of forage supply to grazing animals throughout the annual production cycle. Within broad limits, dry matter (DM) production is relatively insensitive to management of defoliation frequency, severity and duration. However defoliation management has effects on feed quality which can be enhanced, in particular, by control of pasture growth in the spring through maintenance of relatively low average pasture masses. Treading damage can have significant immediate and ongoing effects on pasture production and farmers can use a range of management techniques to minimise these.

Fertiliser application practices have a potent influence on pasture production and seasonality of that production. Available soil nitrogen is the primary nutrient deficiency limiting production in New Zealand's characteristically grass-dominant pastures. Nitrogen fertiliser usage has increased markedly in recent years, particularly to grow substantially greater amounts of forage during the cool season, and this trend looks set to continue. However, the use of nitrogen fertiliser has important environmental implications.

Pasture renewal and forage crop use has also increased in recent years. Care needs to be taken in conducting cost-benefit analyses, selecting the options that best meet the needs, and in establishment and subsequent management practices. Ryegrass (perennial and hybrids) and white clover remain the primary choice for permanent pasture renewal, the availability of safe endophytes having largely alleviated effects of endophyte toxicosis. Special-purpose mixtures are used, especially in dry environments. Italian ryegrasses, brassicas and chicory are common choices for forage crops. A range of management techniques can be used to alleviate deleterious effects of some forages, including ryegrass endophyte toxicosis, facial eczema, and toxins associated with Fusarium fungi. Generally these techniques are not totally effective. More research is required to increase our understanding of these disorders, and in order to develop more effective and reliable management practices.     

Ordered mesoporous materials from metal nanoparticle-block copolymer self-assembly

The synthesis of ordered mesoporous metal composites and ordered mesoporous metals is a challenge because metals have high surface energies that favor low surface areas. We present results from the self-assembly of block copolymers with ligand-stabilized platinum nanoparticles, leading to lamellar CCM-Pt-4 and inverse hexagonal (CCM-Pt-6) hybrid mesostructures with high nanoparticle loadings. Pyrolysis of the CCM-Pt-6 hybrid produces an ordered mesoporous platinum-carbon nanocomposite with open and large pores (>/=10 nanometers). Removal of the carbon leads to ordered porous platinum mesostructures. The platinum-carbon nanocomposite has very high electrical conductivity (400 siemens per centimeter) for an ordered mesoporous material fabricated from block copolymer self-assembly.     

Initial responses of woody vegetation, water quality, and soils to harvesting intensity in a Texas bottomland hardwood ecosystem

Sustainable management of bottomland hardwood forest ecosystems requires a knowledge of responses to management impacts, including timber harvesting. The effects of clearcutting and partial cutting on woody vegetation regeneration dynamics, surface and groundwater quality, soil physical properties, and soil respiration were tested in a bottomland hardwood ecosystem in southeastern Texas, USA, through comparison with non-cut control areas. Overstory removal only slightly affected composition of woody vegetation regeneration 1 year after harvesting compared with pre-harvest composition. Initial composition in both cutting treatments appeared to be the strongest determinant of post-harvest composition, at least for the first year after harvesting. There were few significant differences in groundwater properties when harvesting treatments were compared with control areas during a 17-month period following harvest. Turbidity, temperature, electrical conductivity, dissolved O₂, NH₄-N, NO₃-N, and PO₄-P of streamwater did not vary significantly among treatments. Slight decreases in total and macroporosity were observed in association with higher bulk densities at 0–5 cm depth in the clearcut and partial cut treatments. Saturated hydraulic conductivity values did not decline significantly with treatment intensity. No significant differences among treatments in measured soil physical properties were observed at 5–10 cm depth. Although in situ soil respiration increased with harvest intensity, treatment had no significant effect on mineral soil respiration. In summary, most variables showed only slight response to harvesting, thereby indicating that harvesting practices can be conducted with minimal initial impacts on measured response variables.