Comparison of three in vitro techniques to estimate benzimidazole resistance in Haemonchus contortus of sheep

Three in vitro assays to detect benzimidazole resistance, namely, the egg-hatch assay, tubulin-binding assay, and a larval-development assay, were evaluated by estimating the level of benzimidazole resistance in three field isolates of Haemonchus contortus compared with a susceptible reference strain. Comparisons were also made with estimates of benzimidazole resistance of the three field strains obtained from an in vivo controlled anthelmintic efficacy test. All three in vitro tests showed similar, consistent results which also suggested greater sensitivity than the in vivo assay. These results indicate that selection of an in vitro technique to determine benzimidazole resistance should therefore be based on considerations other than precision, such as technical expertise, availability of equipment, cost and speed in which diagnosis is required.     

Dietary Lysine Requirement of Juvenile Red Drum Sciaenops ocellatus

The dietary lysine requirement of juvenile red drum Sciaenops ocellatus was reevaluated in two separate experiments. In the first experiment, lyophilized red drum muscle was combined with an L-form crystalline amino acid premix to yield diets containing approximately 35% protein on a dry-matter basis. Gradations (0.25%) of L-lysine HCl were added to the basal diet containing approximately 1.0% lysine. Each diet was fed to triplicate groups of juvenile red drum initially weighing 6–7 g for 8 weeks. Based on growth and feed efficiency data, the lysine requirement (±SE) was determined to be 1.55% (±0.079%) of dry diet or 4.430% of dietary protein. In a second experiment, the lysine requirement of red drum was investigated with diets containing 35% intact protein from zein and red drum muscle. Each of the zein-based diets containing incremental levels of lysine was fed to triplicate groups of juvenile red drum initially weighing 1–2 g for 8 weeks. A crystalline amino acid test diet serving as a control in this experiment significantly outperformed the zein-based diets, and palatability of those diets was questionable due to an obvious change in feeding behavior of the fish. Due to the inferior performance of the fish fed the zein-based diets, the authors were not successful in determining a requirement with these diets. Thus, a lysine requirement of 1.55% of dry diet (4.43% of dietary protein) as determined in the first experiment is recommended for juvenile red drum.     

Clinical Evaluation of Three Surgical Methods for Treatment of Caudal Cervical Spondylomyelopathy of Dogs

Sixty-four dogs with caudal cervical spondylomyelopathy (CCSM) caused by chronic degenerative disc disease were treated with ventral decompression (n = 20), linear traction and interbody screw stabilization (n = 7), or linear traction and plastic plate stabilization (n = 37). Interbody screw stabilization was ineffective in treating CCSM because of an unacceptably high rate of implant failures. Ventral decompression or linear traction and plastic plate stabilization were effective in the treatment of most patients with mild to moderate neurologic deficits (neck pain, paraparesis, or ambulatory tetraparesis). Although these techniques were also used successfully in some patients with severe neurologic deficits (weakly ambulatory tetraparesis or nonambulatory tetraparesis), variable success rates and prolonged postoperative recovery periods were noted.     

A Comparison of Arterial and Lingual Venous Blood Gases in Anethetized Dogs

The purpose of this study was to determine whether lingual vanous blood gas samples reflect arterial acid-base gas status in anethetized dogs. Heparinized blood samples were drawn simultaneously from the lingual vein and a peripheral artery in 50 anestheized dogs that were clinical surgical patients, as well as from four experimental dogs in which hemorrahaic shock was being studied. Blood pH, oxygen tension (PO₂), and bicarbonate (HCO_3-)) from the two sources in clinical patients showed significant liner correlation, although arterial PO₂)(PaO₂)) tended to be approximately 110mm Hg higher than lingual venous PO₂). During hemorrahgic shock, however, PaO₂) and PaCO₂) were significantly different from lingual venous PO₂) and PCO₂), Lingula venous blood gas analysis may be useful in assessing acid-base and blood gas status in routline cases, but should not be relied upon in dogs with low cardiac output or poor perfusion.     

Prospects for biological control of nematode parasites of ruminants

Control of nematode parasites in ruminants is directed almost exclusively at the parasitic stage in the host using conventional anthelmintic therapy. However, to complete their life cycle, parasites have to develop through a series of free-living stages on pasture. It is within this environment that there is a vast range of cohabiting micro-organisms, some of which are known to infect or prey on nematodes. These include bacteria, protozoa, viruses and fungi. To date, most interest has been focused on those organisms producing chemical toxins which have been developed as anthelmintics, e.g. Streptomyces/avermectins. Yet the potential of predacious and nematoxic fungi and bacteria for the biological control of nematode parasites of livestock remains largely untapped. These organisms may well offer a cheaper and more sustainable approach to reducing the impact of parasitism in livestock.