Living in an amphidromous world: Perspectives on the management of fish passage from an island nation

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Different landscape features within a simplified agroecosystem support diverse pollinators and their service to crop plants

Landscape Ecology - Landscape simplification is a main driver of insect decline, threatening crop pollination services. Changes in functional features in simplified agroecosystems may impact the...     

Digestible energy intake, dry matter digestibility and mineral status of grazing New Zealand Thoroughbred yearlings

AIM: To measure the nutritive value of pasture in terms of digestible energy intake (DEI) and dry matter (DM) digestibility, and to determine the effect of Ca, P, Cu, Zn, and Se supplementation on growth rate and degree of physeal swelling in Thoroughbred yearlings grazed on pasture. METHODS: Fourteen yearling horses were randomly allocated to 1 of 2 groups and rotationally grazed on a ryegrass/white clover pasture for 7 months. One group was supplemented daily with a mineral mix. Liveweight changes were recorded at fortnightly intervals and pasture mineral composition determined at monthly intervals. The DM intake (DMI) was determined from daily faecal DM outputs divided by the indigestible DM fraction (1 - digestible DM) determined from a digestibility study. The DEI was determined from the difference between the gross energy intake and the gross energy faecal output. The DM, gross energy content, crude protein (CP), soluble carbohydrate, acid detergent fibre (ADF), neutral detergent fibre (NDF), lipid and mineral composition of pasture offered and faeces were analysed and their digestibility or apparent absorption calculated. RESULTS: The DM digestibility of pasture averaged 0.64 while the daily DMI and DEI of a 350 kg yearling, gaining 0.6 kg liveweight/day, averaged 6.9 kg DM/day and 78 MJ DE/day, respectively. The mineral supplement had no significant effect on the growth of yearlings grazing pasture that had a mineral composition of (g/kg DM) Na 0.17, K 32.8, Ca 3.6, P 3.4, Mg 2.1, S 3.0, and (mg/kg DM) Cu 7.9, Fe 177, Mn 83, Zn 28 and Se 0.016. Plasma Se was elevated (e.g. 40-218 microg/l) by Se supplementation while Cu supplementation had no effect on plasma and liver Cu concentrations. Physeal swelling was observed in all horses, regardless of treatment. CONCLUSION: Good quality ryegrass/white clover pasture that had a DE content of 11.3 MJ/kg DM and adequate mineral composition (as observed in this study, with the possible exception of Se) will provide an adequate intake of nutrients to ensure good growth in yearling horses.     

Detection of virus diseases affecting almond nursery trees in western Anatolia (Turkey)

The purpose of this study was a comprehensive survey on the occurrence and distribution of the viruses affecting almond nursery trees in western Anatolia (Turkey). Three provinces (Aydýn, Balýkesir and Ýzmir) which are well known for their state and commercial nursery plantations of almond (mixed with other stone fruits) were visited and 19 300 and 19 000 almond nursery trees were surveyed in 1992 and 1993, and 56 and 40 leaf samples collected, respectively. The main viral symptoms were chlorotic and necrotic spots, calico, mosaic, narrowing and deformation of the leaves; gummosis, weak growth, dwarfing and short internodes of the trees. DAS-ELISA was used to detect prunus necrotic ringspot ilarvirus (PNRSV), prune dwarf ilarvirus (PDV), raspberry ringspot nepovirus (RRV), peach rosette mosaic nepovirus (PRMV) and tomato ringspot nepovirus (ToRSV) in almond nursery trees in west Anatolia. PNRSV was found to be the most widespread according to ELISA. PDV was the second most important virus, and some samples were infected with both ilarviruses. Fewer samples were found infected with PRMV, RRV and only a few samples were infected with ToRSV.     

Use of immunochemical techniques for the analysis of pesticides

Immunochemical assays for small molecules such as pesticides are rapidly gaining acceptance among analytical chemists. These techniques are rapid, sensitive, cost effective and can easily cope with large sample loads. This review lists the advantages and disadvantages of the technique and describes the steps in assay development using examples from this laboratory, particularly the thiocarbamate herbicide molinate and the triazine herbicides. The focus is primarily on hapten synthesis strategies, assay format considerations, sample preparation and assay validation.     

Association of Fertility with Numbers of Antral Follicles within a Follicular Wave During the Oestrous Cycle in Beef Cattle

The association between conception rate at first service and numbers of follicles developed during a follicular wave was examined in 102 suckled beef cows and 14 heifers. Follicular development was monitored using ultrasonography for either two (trial 1) or three (trial 2) consecutive oestrous cycles (pre-breeding, breeding and post-breeding equivalent). Animals were examined on alternate days from day 6 after first oestrus (day 0) until ovulation and from day 6 after insemination until next ovulation or day 24 of pregnancy and were observed for oestrus twice daily and inseminated artificially at either the second (trial 1) or third oestrus (trial 2). Cows were classified as having two or three waves of follicular development for each oestrous cycle. Numbers of follicles >or=4 mm per wave were determined, and based on the maximum diameter they attained, were classified as small (4-6 mm), medium (7-10 mm) or large (>or=11 mm) follicles. Total numbers of follicles, and primarily numbers of small and medium follicles, were affected by trial and within trial by cow, oestrous cycle and follicular wave. Heifers had more small and total numbers of follicles, but fewer large follicles than cows in trial 1 (p < 0.05). The average number of antral follicles per wave in the breeding cycle or post-breeding period did not affect conception rates, which averaged 84%. Repeatability of the total numbers of antral follicles between and among oestrous cycles and follicular waves ranged from 0.01 to 0.97. In conclusion, fertility was not affected by the numbers of antral follicles >or=4 mm in diameter in a single follicular wave.