Age determination and validation studies of marine fishes: do deep-dwellers live longer?

Age determination and validation studies on deep-water marine fishes indicate they are difficult to age and often long-lived. Techniques for the determination of age in individual fish includes growth-zone analysis of vertebral centra, fin rays and spines, other skeletal structures, and otoliths (there are three sets of otoliths in most bony fish semicircular canals, each of which is made of calcium carbonate). Most have regular increments deposited as the fish (and its semicircular canals) grows. The most commonly used otolith for age determination is the largest one called the sagitta. Age validation techniques include: (1) tag-recapture, often combined with oxytetracycline injection and analysis in growth-zones of bone upon recapture; (2) analysis of growth-zones over time; and (3) radiometric approaches utilizing a known radioactive decay series as an independent chronometer in otoliths from bony fishes. We briefly summarize previous studies using these three validation approaches and present results from several of our radiometric studies on deep-water, bony fishes recently subjected to expanding fisheries. Radiometric age validation results are presented for four species of scorpaenid fishes (the bank, Sebastes rufus, and bocaccio, S. paucispinis, rockfishes, and two thornyhead species, Sebastolobus altivelis and S. alascanus). In addition, our analysis of scorpaenids indicates that longevity increases exponentially with maximum depth of occurrence. The reason that the deep-water forms of scorpaenid fishes are long-lived is uncertain. Their longevity, however, may be related to altered physiological processes relative to environmental parameters like low temperature, high pressures, low light levels, low oxygen, and poor food resources.

Control of fatty liver syndrome in a Jersey herd by a change of diet and the use of recombinant bovine somatotrophin.

A Jersey herd was investigated following a decrease in milk yields. The cattle were permanently housed and fed a complete diet in four groups on the basis of yield. They were generally healthy, but the dry cows and many of the milking cows were over fat. The plasma concentrations of beta-hydroxybutyrate and glucose were normal, but the activities of aspartate aminotransferase and glutamate dehydrogenase and the concentration of non-esterified fatty acids were high. Fatty liver syndrome was diagnosed. All the dry cows were condition scored and placed into one of three dietary groups according to their score. They were exercised in an outdoor paddock and entered the pre-calving feeding group at least two weeks before calving; 75 per cent of them achieved a condition score of less than 3, and most of them produced normal milk yields. Thirty cows which had developed signs of fatty liver syndrome were paired and one of each pair received an injection of 640 mg of recombinant bovine somatotrophin. The yield of the treated cows was significantly higher (P < 0.05) for the first two weeks after the injection. The treated cows had higher plasma concentrations of beta-hydroxybutyrate and non-esterified fatty acids and lower plasma urea concentrations seven days after the injection. No other biochemical parameters were affected.

Bovine spongiform encephalopathy statement of possible relation with new variant Creutzfeldt-Jakob disease: effects on the welfare of United kingdom cattle.

Although measures to control bovine spongiform encephalopathy (BSE) had been in force in the United Kingdom for many years and had resulted in a marked decline in clinical cases, the announcement by the Secretary of State for Health on March 20, 1996, that a new variant form of Creutzfeldt-Jakob Disease may be linked with exposure to BSE, resulted in the introduction of several new control measures. These measures included a scheme banning human consumption of meat from cattle who were more than 30 months old (the so-called "over 30-month scheme;" OTMS), a subsidy for slaughter of calves, and additional inspections of abattoirs. The altered slaughter procedures and lack of rendering facilities meant an initial backlog of OTMS animals having to remain on farms. This placed pressures on accommodation and feed stocks, the latter being in short supply because of a poor grass growth the previous summer. Initially, the long delay before the removal of casualty animals from the farm resulted in increased summer mastitis problems for nonlactating cows. The export of calves to the European Union for veal production was banned, thereby allowing the cessation of a previously legal trade that was considered distasteful by many members of the general public. Financial concerns disturbed and continue to disturb affected farmers.

Suspected nutritional deficiency causing anaemia in llamas (Lama glama).

A case of poor condition and recumbency in a 14-month-old female llama and a case of poor condition and ataxia in a 23-month-old male llama are described. Both animals were anaemic and had low plasma copper levels. An increased intake of feed with a higher copper level and treatment with copper injections and an oral mineral solution resulted in a successful recovery. Two other young llamas also had low plasma copper levels. The problem was probably due to a nutritional, particularly copper, deficiency and the animals recovered as their copper levels increased.

Efficacy of recombinant bovine somatotrophin in the treatment of fat cow syndrome.

Recombinant bovine somatotrophin was used in addition to conventional therapy to treat a sample of post-calving cows in a herd suffering a high incidence of fat cow syndrome. Somatotrophin was also given to cows before they calved. There were no significant differences between the treated and untreated groups in the plasma concentrations of glucose, beta-hydroxybutyrate, albumin, total protein or calcium. Significant decreases in mean plasma urea concentration were observed in the pre-calving cows seven and 10 days after treatment with somatotrophin, and a significant decrease in mean plasma urea concentration was also recorded in post-calving cows with the fat cow syndrome. There was no evidence that somatotrophin, with its many potent actions in cows with acetonemia, exacerbated clinical ketosis. The authors' subjective clinical impression was that somatotrophin was helpful in the treatment of cows with the fat cow syndrome.