Effects of cimetidine on broiler fattening and on stress-induced gizzard erosion in chicken.

The work describes the effects of cimetidine on stress-induced gizzard erosions (Experiment A) and the influence of the long-term application (42 days) of the same drug on weight gain and feed consumption during broiler fattening (Experiment B). For Experiment A, 60 male, three-day-old chicks were divided into two groups: C (n = 30)--control chicks treated with 0.5 ml saline; CIM (n = 30)--chicks treated with cimetidine in a dose of 5 mg/kg body weight (b. w.) intragastrically. All chicks were stressed using a modified water-immersion stress method according to which the chicks, after 24 h of feed deprivation, were immersed in tap water (17 degrees C) for a few seconds. Under chloroform anaesthesia ten chicks from each group were killed 1, 2 and 3 h after the stressing. The morphometric analysis of gizzard erosion (GE) and histopathological examinations of gizzards were performed for each chick. In Experiment B, 32 one-day-old broilers of both sexes were used. The control group was untreated (n = 16) while the CIM group (n = 16) was fed the same diet supplemented with 10 mg of cimetidine per kilogram of feed throughout the fattening period (42 days). The results of Experiment A showed decreased mean length of the GE in the cimetidine-treated birds as compared with the GE lesions of the controls. In Experiment B, the treated chicks had reduced liveweight (1835.1 g), carcass weight (1474.6 g) and increased feed consumption (2115 g of feed per kilogram of weight gain) compared to the controls in which the same parameters were 1898.5 g, 1574.2 g and 1797 g, respectively. The results show that while stress-induced GE of chicks can be medicated pharmacologically, long-term application of the same substance impairs the results of fattening.     

Tree–grass interactions for N in Nothofagus antarctica silvopastoral systems: evidence of facilitation from trees to underneath grasses

Nothofagus antarctica forests in south Patagonia are usually used as silvopastoral systems but how grasses and trees compete for specific resources, such as nitrogen in these systems is unknown. To understand interactions between grasses and N. antarctica trees for N, an experiment with ¹⁵N labeled fertilizer was carried out comparing N absorption by grasses growing under trees (silvopastoral system) with an open site. Labeled ¹⁵NH ₄ ¹⁵ NO₃ fertilizer at 10 % atom excess was added in spring at both sites and ¹⁵N was measured in herbage, soil and trees every 30 days during the growing season. Soil was the component that containing the greatest amount of N and greatest ¹⁵N recovery. Grasses growing in the silvopastoral system absorbed almost double of the fertilizer applied than grasses in the open site (32.4 kg N ha^?1derived from fertilizer based on ¹⁵N recovery). Roots were also an important fate for N absorbed, representing 50 and 63 % of total ¹⁵N recovered in grass roots of open and silvopastoral sites, respectively. Trees absorbed 69 % less applied N than grasses in the silvopastoral system; being mainly allocated in small branches, sapwood and fine roots. Overall, ¹⁵N recovery was 65 % higher in the silvopastoral system (tree + grasses) than in the open site (grasses). Silvopastoral system made more efficient use of the ¹⁵N added. These results indicated that N. antarctica trees in the silvopastoral system may “facilitate” fertilizer N absorption of grasses by improving environmental conditions like water availability or by reducing competition for inorganic N between soil microorganisms and plants.     

Effect of different daily doses of gizzerosine on the serum 1,25-dihydroxycholecalciferol concentration in laying hens

Five groups of laying hens were treated with different gizzerosine doses (0, 2.5; 5.0; 7.5; 10.0 mg/kg/body weight of gizzerosine) daily over a 21-day period to determine the serum concentrations of 1.25-dihydroxycholecalciferol (1,25(OH)2D), total calcium, inorganic phosphorus and magnesium. Blood samples were taken on days 7, 14, and 21 of the experiment. The concentration of 1,25(OH)2D remained unchanged after day 7 in the gizzerosine-treated birds compared to the control group. After 14 days, it was significantly lower in the birds receiving. gizzerosine, compared with the control group. On day 21, 1,25(OH2)D concentrations were also significantly decreased in all 4 gizzerosine-treated groups compared with the control hens. The serum total calcium, inorganic phosphorus and total magnesium concentrations varied significantly, but irregularly, during the period of the study.     

Blood parasites of sheep in the Netherlands. I. Anaplasma mesaeterum sp.n. (Rickettsiales, Anaplasmataceae)

Summary On two occasions an anaplasm was isolated from sheep on the Dutch island of Ameland. The organism proved to be highly pathogenic for splenectomised sheep; a non-splenectomised animal recovered spontaneously after the packed cell volume had decreased by 40%. Treatment with oxytetracycline was effective. Its pathogenicity for goats appeared to be low, and the organism was apparently not infective to splenectomised cattle. This anaplasm differs from Anaplasma ovis in that less than 30% of the organisms are marginally situated in the red cell, as against over 70% in A. ovis; cross-immunity with A. ovis was incomplete and the latter appeared to be far more pathogenic to goats than the Dutch anaplasm, for which the name Anaplasma mesaeterum sp.n. is proposed. Its ultrastructure is similar to that of A. marginale and A. ovis. The vector is either Ixodes ricinus or Haemaphysalis punctata. Its practical importance remains to be ascertained.     

Changes in understory species diversity during theNothofagus pumilio forest management cycle

Human commercial activities must be compatible with sustainable management to achieve species conservation in the natural environment. After harvesting, diversity and abundance of understory species differ substantially from the pre-harvest situation. Have knowledge of the changes that logging produces in all components of the system allows us to develop management alternatives with reduced impacts. The objective of this work was to evaluate changes in density, biomass and diversity of understory species along a forest shelterwood cut system management cycle in aNothofagus pumilio forest. Six forest management situations (postharvesting stands and different phases of forest development) were sampled in a pureN. pumilio forest of Tierra del Fuego (Argentina) of middle-high site class (fromclass I toIII). Species number, density and biomass were modified substantially after a shelterwood cut. These were being greatest after cutting and falling substantially when the forest canopy closes during theinitial growth phase, returning to values similar to this virgin forest when themature phase was reached. The impact of the forest management on understory species diversity is analyzed and discussed. The silvicultural practices applied toN. pumilio forest in Tierra del Fuego permit the introduction of alien flora to the system, and produce great changes during the forest management cycle. To Celina Matteri, Itatí Ferraro, and Rosa Kofalt for their aid in taxonomical identification. To Juan Manuel Cellini, Ricardo Vukasovic and Gregorio Martínez Pastur for their participation in the field work; and to the sawmillLos Castores, Universidad Nacional de la Patagonia Austral, Centro Austral de Investigaciones Científicas and Instituto Nacional de Tecnología Agropecuaria for the institutional and financial support.     

Borrelia infections of ruminants in Europe

The occurrence of Borrelia spirochaetes in cattle in the Netherlands is reported for the second time, and in red deer and roe-deer in Austria for the first time. It is postulated that these spirochaetes are Borrelia burgdorferi rather than B. theileri. The reservoir role of ruminants in the epidemiology of human disease caused by B. burgdorferi in Europe should be investigated.     

Early growth and quality of radiata pine in a silvopastoral system in New Zealand

The effect of different understoreys on the early growth and quality of radiata pine (Pinus radiata) in a silvopastoral system was evaluated in Canterbury, New Zealand. Fitted models successfully represented the effect of understorey on the growth (basal area and height) and a quality of trees (diameter over stubs). Basal area, diameter, height and volume growth were affected by understorey competition. Trees growing with no-understorey had 34%and 29% higher volume than trees growing with lucerne (Medicagosativa) and cocksfoot (Dactylis glomerata)understoreys, respectively. However, the height of trees at age 10 grown without understorey competition was only 9% and 15% more than trees grown with grass and lucerne understorey, respectively. Understorey competition effects on growth became more evident during the summer and early autumn months when water deficits occurred. The quality of trees was also affected by understorey competition. While trees grown in bare ground had higher growth than trees grown with understorey competition, they had the poorest stem quality with higher diameters over stubs, branch size, sweep and proportion of stem defects. This will have an impact on the agroforestry system profitability by affecting the net harvest revenue. This revised version was published online in June 2006 with corrections to the Cover Date.     

Dry matter production,morphology and nutritive value of <Emphasis Type="Italic">Dactylis glomerata</Emphasis> growing under different light regimes

Plant growth, morphology and nutritive value under shade can differ between temperate grasses. Therefore, the aim of this study was to quantify the dry matter (DM) production, sward morphology, crude protein (CP%), organic matter digestibility (OMD) and macro-nutrient concentrations (P, K, Mg, Ca and S) in a grazed cocksfoot (Dactylis glomerata L.) pasture under 10-year-old Pinus radiata D. Don forest. Four levels of light intensity were compared: full sunlight (100% photosynthetic photon flux density-PPFD), open + wooden slats (∼43% PPFD), trees (∼58% PPFD) and tree + slats (∼24% PPFD). The mean total DM production was 8.2 t DM ha⁻¹ yr⁻¹ in the open and 3.8 t DM ha⁻¹ yr⁻¹ in the trees + slats treatment. The changes in cocksfoot leaf area index (LAI) were related to variations in morphological aspects of the sward such as canopy height and tiller population. CP% increased as PPFD declined with mean values of 18.6% in open and 22.5% in the trees + slats treatment. In contrast, the intensity of fluctuating shade had little effect on OMD with a mean value of 79 ± 3.2%. The mean annual macro-nutrient concentrations in leaves increased as the PPFD level declined mainly between the open and the trees + slats treatments. It therefore appears that heavily shaded dominant temperate pastures in silvopastoral systems limit animal production per hectare through lower DM production rates and per animal through reduced pre-grazing pasture mass of lower bulk density from the etiolated pasture.     

Local management to support local fisheries: Rāhui (temporary closure) and bag limits for blackfoot abalone (Haliotis iris) in southern New Zealand

1. Spatially discrete stocks that vary in life history traits on a reef-to-reef scale present a challenge for fisheries managers. Nationally or regionally applied one-size-fits-all approaches to management fail to account for this variability, and when coupled with fishing pressure this can result in serial depletion and localized extinction.
2. Where mechanisms for local management exist, as they do in New Zealand via customary protection areas (Taiāpure Local Fisheries, Mātaitai Reserves), managers have the opportunity to trial tools on scales relevant to the stocks managed. This study assesses the effect of bag limits and a rāhui (temporary closure) in managing the spatially discrete, and culturally important, blackfoot abalone (Haliotis iris, pāua) in the East Otago Taiāpure, in southern New Zealand.
3. Using surveys spanning 8 years and 26 sites, the rāhui was found to have had mixed results: halting the decline in pāua density at 0 m but not 0.5 m depths. The rāhui did, however, result in an increase in the percentage of individuals above the minimum legal size at both depths.
4. Where bag limits alone had been applied, pāua densities and the percentage of legal-sized individuals continued to decline over the 8-year period, with the loss of large individuals, translating into a decline in estimated egg production.
5. Growth estimates from mark–recapture and surveys of juvenile abundance at sites inside and outside the rāhui highlight the fine-scale variability in pāua life history even within this local area. This suggests there may be biological impediments to pāua management using bag limits alone.
6. Though pāua restoration efforts have had mixed results to date, this study highlights the potential for legally empowered local managers and communities to respond to fisheries declines in their own local area in an action-driven, adaptable, and timely way.