Failure of zinc supplementation to prevent severe facial eczema in cattle fed excess copper

CASE HISTORY: A 400-cow dairy unit in the Waikato suffered a severe outbreak of facial eczema (FE) despite consistent zinc supplementation and significantly elevated serum zinc concentrations.

CLINICAL FINDINGS: FE prevention had begun in mid-January 2006, via zinc sulphate supplementation in the water. Photosensitisation was reported on 06 April, contemporaneous with a marked increase in the number of Pithomyces chartarum spores in pasture samples. Within 10 days of this first clinical case, 100 affected cows had been dried off, eight of which subsequently died or were culled. Blood samples were collected from ten affected cows; all had serum zinc concentrations >17 µmol/L, and eight had gamma-glutamyl transferase (GGT) activities >200 U/ml, indicating that the photosensitisation was secondary to liver damage, i.e. probably FE. Further investigation identified that this herd had been receiving excess copper supplementation; 4/6 culled cows had liver copper concentrations within or above the marginal range for copper toxicity.

DIAGNOSIS: Severe FE despite zinc supplementation that increased serum zinc concentrations above recommended levels

CLINICAL RELEVANCE: As zinc supplementation significantly reduces apparent copper status, copper supplementation is often used to counteract this. Previous excess copper intake may reduce the efficacy of zinc in preventing FE, thus copper intake should be assessed prior to the start of zinc supplementation.     

Evaluation of Efficacy and Safety of Zinc Gluconate Associated with Dimethyl Sulphoxide for Sexually Mature Canine Males Chemical Neutering

The aim of this research was to evaluate the efficacy of zinc gluconate associated with dimethyl sulphoxide (DMSO) for chemical neutering in canine males. Fifteen sexually mature male dogs were divided in two groups, named control and treated. An injection was administered to both testicles, at a concentration of 26.2 mg zinc gluconate per ml and 0.5% DMSO in the treated group (11 dogs). The control group was given injections of saline solution (four dogs). Clinical examination and blood collection for a haemogram were done both before and after drug injection. There were 12 spermograms performed to analyse sperm motility, sperm vigour, ejaculate volume, testicle size, pathology and sperm concentrations. Libido was also measured. An ultrasound examination and histopathology were performed at the end of the experiment. Dogs’ libido after chemical injection was reduced by over 50%. The spermogram analysis showed final mean results of 14.54% for sperm motility, 0.72 of sperm vigour and 37 150 per million spermatozoa per millilitre, values considered below the necessary levels at which fertilization can occur. Ultrasound and histopathology analyses of testicles for the treated group revealed more intense injuries when compared with the control group, with compromised testicular parenchyma and a decrease of germ cell number leading to total atrophy, indicating that the treatment reduced the fertilizing potential of male dogs, promoting a possible subfertile status.     

Lignocaine versus bupivacaine for flank anaesthesia using multiport catheters via a caudal epidural approach in cattle

Objective To determine the anaesthetic and systemic effects of dorsolumbar epidural anaesthesia using non-stylet multiport catheters via the caudal approach to administer hypertonic 5% lignocaine (HL) or hypertonic 0.5% bupivacaine (HB) to the flank in standing cattle. Materials and methods Six healthy adult cattle weighing 310–455 kg received 0.2 mg/kg HL or 0.025 mg/kg of HB; control animals received 0.9% saline solution. All drugs were injected into the dorsolumbar epidural space via a caudal approach through a non-stylet multiport catheter. Each animal received each treatment at random. Evaluations of anaesthesia, ataxia, heart rate, arterial pressures, respiratory rate and rectal temperature were obtained at 0 (basal), 5, 10, 15, 30, 45, 60, 75, and 90 min after epidural injection and then at 30-min intervals until loss of anaesthesia. All animals received a standard noxious stimulus and a 4-point scale was used to score the response. A second scale was used to score ataxia. Results The duration of anaesthesia in the upper and lower flanks in cattle was 68 ± 12 and 110 ± 15 min (mean ± SD) after dorsolumbar epidural HL or HB, respectively. Both hypertonic local anaesthetics produced a mild ataxia. The systemic changes were within acceptable limits in these clinically healthy cattle. Conclusion In standing cattle the dorsolumbar epidural injection of hypertonic lignocaine provided faster onset of anaesthesia and fewer cardiovascular effects, but had a shorter duration of anaesthesia than hypertonic bupivacaine.     

Volatiles from the 1994 Eruptions of Rabaul: Understanding Large Caldera Systems

The 1994 eruption of Rabaul, in Papua New Guinea, involved a small plinian eruption at Vulcan and a vulcanian eruption on the opposite side of the caldera at Tavurvur. Vulcan's ash leachates indicate seawater interaction that is consistent with earlier observations of low sulfur dioxide emissions and the presence of ice crystals in the initial plinian eruption cloud. In contrast, Tavurvur ash leachates indicate no seawater interaction, and later sulfur dioxide emissions remained high despite low-level eruptive activity. Silicic melt inclusions indicate that the andesitic melt contained about 2 weight percent water and negligible carbon dioxide. Mafic melt inclusions in Tavurvur ash have water and carbon dioxide contents that vary systematically over the course of the eruption. The mafic melt inclusions suggest that a mafic dike intruded from below the silicic chamber and provide further evidence that mafic intrusions drive caldera unrest.     

Methanol as cryoprotectant and the suitability of 1.2 ml and 5 ml straws for cryopreservation of semen from salmonid fishes

For salmonid semen, the cryoprotective action of 10% methanol was compared with a 5% dimethyl sulphoxide (DMSO), 1% glycerol mixture, until now one of the most effective cryoprotectants. In Oncorhynchus mykiss (Walbaum), Salmo trutta L. f. fario, Salmo trutta L. f. lacustris and Salvelinus alpinus (L.), semen cryopreserved with both cryoprotectants yielded post-thaw fertilization rates of 90-100% of control with untreated semen at sperm-to-egg ratios of 1.8 × 10⁶-2.4 × 10⁶ spermatozoa per egg. However, at sperm-to-egg ratios of 0.9 × 10⁶-1.2 × 10⁶ spermatozoa per egg, semen cryopreserved with methanol had significantly higher fertilization rates than semen frozen with the DMSO/glycerol mixture. In other studies we obtained similar data for Coregonus sp., Salvelinus fontinalis (Mitchill), Thymallus thymallus (L.) and Hucho hucho (L.), proving that methanol is the most effective and generally applicable cryoprotectant for semen of the studied salmonid species. To facilitate the insemination of large egg batches we investigated the suitability of 1.2 ml and 5 ml straws for deep freezing of semen of Oncorhynchus mykiss, Salmo trutta f. fario, Salmo trutta f. lacustris and Salvelinus alpinus. With 1.2 ml straws the fertilization rates were similar to 0.5 ml straws when using lower freezing and higher thawing temperatures. The 5 ml straws resulted in a fertilization success of only about 40% of fresh semen control.     

Post-cambrian trilobite diversity and evolutionary faunas

A cluster analysis of the stratigraphic distribution of all Ordovician trilobite families, based on a comprehensive taxonomic database, identified two major faunas with disjunct temporal diversity trends. The Ibex Fauna behaved as a cohort, declining through the Ordovician and disappearing at the end-Ordovician mass extinction. In contrast, the Whiterock Fauna radiated rapidly during the Middle Ordovician and gave rise to all post-Ordovician trilobite diversity. Its pattern of diversification matches that of the Paleozoic Evolutionary Fauna; hence, trilobites were active participants in the great Ordovician radiations. Extinction patterns at the end of the Ordovician are related to clade size: Surviving trilobite families show higher genus diversity than extinguished families.