New Zealand Veterinary Journal Volume 58 Issue 3

New Zealand Veterinary Journal Volume 58 Issue 3

The June issue of the NZVJ includes the first report globally on the field efficacy of a new derquantel-abamectin combination anthelmintic for sheep produced by Pfizer Animal Health. The issue also contains a stimulating discussion paper on the legal and ethical issues for veterinarians dealing with abuse of animals, and a series of papers examining the copper status of dairy cows in New Zealand.

For all veterinarians and veterinary business owners, Ian Robertson, a veterinarian and lawyer, considers the responsibilities of veterinarians to report suspected abuse of both animals and humans, which is a legal as well as an ethical duty. Currently veterinarians may face a risk of legal liability when reporting abuse. Suggestions are made for the profession to adopt a policy of mandatory reporting, while at the same time providing legislative immunity. The implications of such a policy are discussed.

For sheep practitioners, Peter Little and colleagues from Pfizer Animal Health present the results of field studies that evaluated the efficacy of a new anthelmintic combination, derquantel-abamectin in sheep. On 14 properties throughout New Zealand groups of sheep were treated with the test anthelmintic, or remained as untreated controls. On nine properties additional treatment groups received other anthelmintics. Faecal nematode egg count reduction tests were used to determine the efficacy of all treatments. On all properties the efficacy of  derquantel-abamectin was >99%, including those where resistance to other anthelmintic was demonstrated.

For cattle practitioners, a series of three papers addressing the copper status of dairy cows is presented by Neville Grace and colleagues. In the first, the change in copper status of dairy cows in 10 herds in the Waikato region is examined by Neville Grace and colleagues from AgResearch and The Veterinary Centre, Te Awamutu. Comparing liver biopsy samples taken from live cows and from slaughtered cull cows, both were useful for indicating the copper status of herds. A surprising finding was that most herds had an adequate status and copper toxicity may be a potential problem.

In the second paper, Stefan Smith and colleagues from Massey University, AgResearch and Agvance Marketing Ltd. present the results of an experiment examining the interaction between zinc and copper supplementation in non-lactating dairy cows fed silage. Cows were either supplemented or not with copper for 56 days. Within each group half received zinc oxide boluses, used for the prevention of facial eczema. Copper supplementation increased concentrations of copper in the liver, however additional supplementation with zinc significantly reduced liver concentrations of copper.

In the third paper, Shaun Balemi from Agvance Marketing Ltd. and colleagues from AgResearch and Massey University present the results of a study examining the changes in concentration of copper in the liver of dairy cows fed a copper deficient diet and given various copper supplements over 116 days. Concentrations of copper in the liver of unsupplemented cows decreased during this period, whereas supplementation with oral solutions of copper or a bolus of CuO wire particles resulted in increased concentration. Treatment with injectable copper did not affect liver concentrations.

Also on cattle, as well as sheep, Wayne Campbell and colleagues from Massey University present the results of an in-depth study examining the metabolites that are thought to be involved in plant- or mycotoxin-induced phototsensitivities. Detailed laboratory investigations were undertaken to identify and measure the chlorophyll a metabolites, specifically phytoporphyrin (= phylloerythrin), as well as pheophorbide a and pyropheophorbide a using chromatographic and spectroscopic techniques. A method was developed for the quantification of phytoporphyrin in the blood of photosensitive animals, that will be a useful tool for the investigation of outbreaks of, for example, spring eczema.

On goats, and in relation to stress physiology, Eloy Redondo and colleagues from the University of Extremadura, Cáceres, Spain present the results of an experiment that examined the interaction between stress and the pineal gland. Goat kids were separated from their dams at 4 days of age (weaned) or allowed to suckled twice daily. Half of each group were then treated with melatonin implants for 28 days. In the weaned kids not treated with melatonin, concentrations of cortisol in plasma were significantly higher than in the other groups; this group also had lower concentrations of melatonin, a smaller pineal gland and fewer pinealocytes. Treatment with melatonin resulted in these parameters being similar to those observed in the unweaned kids.

On poultry, a further study investigating the biosecurity risks associated with backyard poultry is presented by Caryl Lockhart and colleagues from Massey University and Biosecurity New Zealand. The prevalence of poultry ownership was low in both urban and urban-rural properties around Palmerston North. In both areas poultry were allowed to free range during the day, thus presenting a risk for contact with wild birds.

For companion animal practitioners, John Munday from Massey University, and colleagues from New Zealand Veterinary Pathology Ltd. and Levin & Horowhenua Veterinary Centre describe an interesting case of a Cavalier King Charles Spaniel that developed multiple inverted papilloma located only on an area of skin that had been clipped prior to ovariohysterectomy. The papillomavirus CfPV-2 was associated with samples from the papllomas. Fortunately the lesions spontaneously resolved 8 weeks after they were first observed.