An Ecological Foodniche Concept as a Proxy for Fish-Pond Stocking Rates in Integrated Aquacultural Farming for Malaysia

The merits of integrated aquaculture farming (IAF) as a strategy for bolstering income for the rural poor have been recognized, but the economic efficiency and sustainability are yet to be determined. The effects of one species on another and the economic benefits, net of government support, have not been critically evaluated. The concept of a foodniche for alternative species in an aquatic environment has not been properly tested in an economic setting. Thus, this report reflects the results of applying the technique of mixed integer linear programming to determine the optimum combination of species within the context of a foodniche. The objective also included maximizing revenues, with minimal external input requirements, for a representative small Malaysian wet-rice farm. It was found that the foodniche concept permitted flexibility in stocking rates, and that farmers could actually stock species at the exact rate that was optimal for profit, instead of standard fixed rates. Also, government subsidies for pond construction were essential for IAF success. The net revenues from IAF were low without interest-free loans for pond construction.     

Small intestinal carcinoma in cattle

The pathology of carcinoma of the small intestine in six adult cattle is described. The lesions were similar to those of carcinoma of the small intestine of sheep although a slightly less fibrous stroma and a greater tendency to metastasise was observed. Initial findings suggest the disease resembles small-intestinal carcinoma of sheep and cola-rectal carcinomas of man in having a higher prevalence in New Zealand than most other countries. This highlights the need to investigate common environmental factors which may be responsible for the induction and promotion of these tumours in both grazing ruminants and man.     

Bovine ceroid-lipofuscinosis: pathology of blindness

Five Devon cattle with suspected ceroid-lipofuscinosis and aged between 19 and 39 months of age were humanely slaughtered and subjected to post-mortem examination. There was severe atrophy of the cerebrum, particularly of the occipital cortex. Microscopy also showed severe atrophy of the retina with complete loss of photoreceptor cells, even in the youngest animal examined. Histopathologically the disease was characterised by accumulation of a fluorescent lipopigment in neurones, including those of the retina and a severe astrocytosis. The disease, which is characterised by the accumulation of subunit c of mitochondrial ATP synthase, is similar to that extensively described in South Hampshire sheep except that the retinal lesions were more severe. In contrast, tremors were not noted in the cattle. The clinical history and similarity to the disease in sheep and other species indicated inheritance was as an autosomal recessive trait.     

The effect of situational variability in climate and soil, choice of animal type and N fertilisation level on nitrogen leaching from pastoral farming systems around Lake Taupo, New Zealand

Agricultural systems with grazing animals are increasingly under scrutiny for their contribution to quality degradation of waterways and water bodies. Soil type, climate, animal type and nitrogen (N) fertilisation are contributors to the variation in N that is leached through the soil profile into ground and surface water. It is difficult to explore the effect of these factors using experimentation only and modelling is proposed as an alternative. An agro-ecosystem model, EcoMod, was used to quantify the pastoral ecosystem responses to situational variability in climate and soil, choice of animal type and N fertilisation level within the Lake Taupo region of New Zealand. Factorial combinations of soil type (Oruanui and Waipahihi), climate (low, moderate and high rainfall), animal type (sheep, beef and dairy) and N fertilisation level (0 or 60 kg N/ha/yr) were simulated. High rainfall climates also had colder temperatures, grew less pasture and carried fewer animals overall which lead to less dung and urinary N returned. Therefore, even though a higher proportion of N returned ultimately leached at the higher rainfall sites, the total N leached did not differ greatly between sites. Weather variation between years had a marked influence on N leaching within a site, due to the timing and magnitude of rainfall events. In this region, for these two highly permeable soil types, N applied as fertiliser had a high propensity to leach, either after being taken up by plants, grazed and returned to the soil as dung and urine, or due to direct flow through the soil profile. Soil type had a considerable effect on N leaching risk, the timing of N leaching and mean pasture production. Nitrogen leaching was greatest from beef cattle, followed by dairy and sheep with the level of leaching related to urine deposition patterns for each animal type and due to the amount of N returned to the soil as excreta. Simulation results indicate that sheep farming systems with limited fertiliser N inputs will reduce N leaching from farms in the Lake Taupo catchment.     

Effect of histamine on lung contractile elements in growing cattle

OBJECTIVE: To determine the effect of histamine on the contractile elements of the respiratory tract in neonatal calves and young adult cattle. SAMPLE POPULATION: Samples of trachealis muscle, bronchi, and intrapulmonary arteries and veins dissected from the respiratory tracts of healthy bovids (2 to 8 days and 16 to 20 months old). PROCEDURE: Histamine cumulative concentration-effect curves (10(-6) to 10(-3) M) were constructed in duplicate smooth muscle samples mounted in organ baths. Contractile responses to histamine were compared with reference contractions elicited by methacholine (10(-5) M) for airways or KCl (127 mM) for vessels. RESULTS: In young adult cattle, trachealis muscle had a substantial contractile response to histamine (84% of methacholine-induced contraction), whereas bronchi reacted slightly (15 and 20% for large and small bronchi, respectively). Although contractile responses to KCl were comparable in arteries and veins, histamine-induced contractions were greater for intrapulmonary veins than for arteries (202 vs 48% of KCl-induced contraction). In neonatal calves, histamine-induced contraction of veins also exceeded that of arteries (230 vs 54% of KCl-induced contraction); however, unlike in young adult cattle, histamine produced notable contraction of large and small bronchi (48 and 60% of methacholine-induced contraction, respectively). CONCLUSIONS AND CLINICAL RELEVANCE: Compared with intrapulmonary arteries, intrapulmonary veins have greater contractile responses to histamine in neonatal and young adult cattle. Data suggest loss of histamine responsiveness in bronchial smooth muscle as neonatal calves grow to young adults. Venodilation may be useful in treatment of lung edema in cattle.     

SciQuest and the complete archive of the NZVJ launched online

The complete archive of the New Zealand Veterinary Journal went online on 1 January 2003 on SciQuest (www.sciquest.org.nz), an innovative new e-publishing website developed by the New Zealand Veterinary Association (NZVA). This follows hot on the heels of the CD-Rom version released from the same platform in June last year. Subscribers in 2003 will be able to search and retrieve, online, the full text of any article published in the journal since its inception in 1952. To date, few veterinary science journals are able to offer such a complete and comprehensive resource. SciQuest's mission is to provide high-speed access to science and continuing education articles to scientists and veterinarians in a fully indexed and searchable format, both online (via the internet) and offline (via CD-Rom). Searching and browsing the archive online is free and abstracts are available for all articles published from 1972 onwards. Access to full text, which is presented in PDF format exactly as published, is restricted to journal subscribers. The site will be updated with each issue of the journal as it is published. The online format will largely suit institutional users and casual enquiries, whereas the offline version is designed to be loaded onto computer hard drives for immediate access, any-time, and is better suited to frequent users and veterinary practitioners. A major advantage of the offline resource is its speed and immediacy, returning search results and full text much faster than the online version, without the need for internet access. The search engine has been designed to suit specific problem-oriented enquiries, and great effort has been expended to ensure the archive is both complete and accurate. The same search engine and interface has been provided on both versions, which allows for fast and highly specific searching of titles and full text of all articles for the occurrence of any word or combinations of words, as well as indexes of author, volume, year, article type, animal type and subject. Search results can be instantly sorted by author and date of publication, and powerful secondary search features such as 'by the same author', 'in the same issue' and 'same subject' links add power and flexibility. The offline version will be updated with annual releases and is available for purchase to subscribers and members of the NZVA.     

Neuronal ceroid lipofuscinosis in Merino sheep

OBJECTIVE: To characterise neuronal ceroid lipofuscinosis (NCL) in Merino sheep. DESIGN: A prospective clinical, pathological, biochemical and genetic study. PROCEDURE: NCL cases were studied from a medium-wool Merino flock, the stud of origin of its replacement rams, and an experimental flock established at the University of Sydney. RESULTS: Behavioural changes and visual impairment were first detected at 7 to 12 months of age and progressed, with associated motor disturbances and at later stages seizures, to premature death by 27 months of age. At necropsy there was severe cerebrocortical atrophy associated with neuronal loss, astrocytosis and the presence in neurons of eosinophilic intracytoplasmic storage bodies with the characteristics of a lipopigment. In the retina there was progressive loss of photoreceptor cells. Storage bodies isolated from fresh brain, liver and pancreas formed electron-dense aggregates and coarse multilamellar and fine fingerprint profiles ultrastructurally, and consisted mainly of the hydrophobic protein, subunit c of mitochondrial ATP synthase. A homozygosity mapping approach localised the gene causing the disease in Merino sheep to the chromosomal region (OAR7q13-15) associated with NCL in South Hampshire sheep. CONCLUSION: NCL in Merino sheep is a subunit c-storing disease, clinically and pathologically similar to NCL in South Hampshire sheep. We propose that the disease in both breeds represents mutation at the same gene locus in chromosomal region OAR7q13-15.     

Neuronal ceroid-lipofuscinosis in Borderdale sheep

AIM: To describe the gross and histological lesions of a neurological disease in Borderdale sheep characterised clinically by blindness and circling, as a basis to its classification. METHODS: Formalin-fixed tissues were processed into paraffin wax and epoxy resin for light and electron microscopy of variously stained sections. RESULTS: Lesions were those of a lysosomal storage disease with severe neurodegeneration of the cerebral cortex. The staining reactions, autofluorescence and ultrastructure of storage material allowed the diagnosis of neuronal ceroid-lipofuscinosis associated with the accumulation of subunit-c of mitochondrial ATP synthase. CONCLUSIONS: The severity of neurodegeneration and minor differences in the ultrastructure of storage material implied that this was a different disease from other forms of ovine ceroid-lipofuscinosis that accumulate subunit-c of mitochondrial ATP synthase. An autosomal recessive mode of inheritance is considered probable. Although of only minor economic importance, this disease may be important to research into the group of ceroid-lipofuscinoses as a whole.     

Mucopolysaccharidosis IIIA (Sanfilippo syndrome) in a New Zealand Huntaway dog with ataxia

AIM: To investigate the nature of a progressive ataxia in a New Zealand Huntaway dog. METHODS: The affected dog was examined clinically before being humanely killed and necropsied. Selected tissues were submitted to light and electron microscopy and to biochemical analyses. RESULTS: The histological lesions were interpreted as indicative of one of the forms of mucopolysaccharidosis type-III (MPS-III), a lysosomal storage disease. Biochemically there was a deficiency of heparan sulphamidase. All the heparan sulphate chains had non-reducing-end glucosamine-N-sulphate residues. CONCLUSION: The disease is MPS-IIIA (Sanfilippo syndrome). An autosomal recessive mode of inheritance can be provisionally assumed from the nature of this disease in other species.