Spatial and temporal stability of soil phosphate concentration and pasture dry matter yield

Several methods are described that could be used by a farm manager to define the spatial and temporal stability within a field from a series of yield maps. A quantitative analysis of soil phosphate concentration and pasture dry matter yield data over 4 years (2004–2007) were investigated to identify the spatial and temporal stability in a 6 ha pasture field. The data were combined into two maps that characterize the spatial and temporal variation recorded over the 4 years. The two maps were then combined to create a single map with five management classes, each with different characteristics that can have an impact on the way the field is managed. These categories are: high yielding and stable, high yielding and moderately stable, low yielding and stable, low yielding and moderately stable and unstable. The unstable class represents 83 and 93% of the total area with regard to soil phosphate concentration and pasture dry matter yield, respectively. Results from this study show that the significant temporal stability found cancels out over time, leaving a relatively homogenous map of spatial variation. The implication of the findings is that each pasture field should be managed according to the current year’s conditions. These results also justify a further study that evaluates the soil phosphorous dynamics under Mediterranean conditions.     

Evaluation of spatial and temporal variability of pasture based on topography and the quality of the rainy season

Yield and botanical composition of a given dry-land pasture are heavily influenced by rainfall distribution, and vary according to topography. Through analyzing these parameters, it is possible to identify patterns of spatial distribution, related to topographic characteristics, which can be used to improve spatial management of pasture. The main objective of this project was to assess the role of rainfall, temperature and topography in the spatial and temporal variability of pasture and establish models for predicting the spatial distribution and yield of certain plant species, based on its topographic characteristics. This study was carried out over three years, 2004 to 2006, in a dry-land pasture located in Southern Portugal. The data obtained were analyzed as a function of distance to flow lines and the results demonstrate that certain topographical characteristics, associated with agronomic information, can be very useful in explaining the spatial and temporal variability of yield and the botanical composition of the pasture. The slope of the linear regression of the variables mentioned can be used to estimate the spatial variation of yield and the botanical composition as a function of distance to flow lines. The regression coefficient can be estimated from the annual rainfall, given the strong correlation between the two.     

Biliary elimination kinetics and tissue concentrations of oxytetracycline after intravenous administration in hens

The pharmacokinetics of the biliary elimination of oxytetracycline (OTC) and tissue concentrations in certain organs were studied in 10 Leghorn hens. The animals were anaesthetized using xylazine/ketamine administered by the intramuscular (i.m.) route and were immobilized for right laparotomy. Both bile ducts were cannulated and a dose of 20 mg/kg of oxytetracycline hydrochloride was administered intravenously (i.v.). Samples of bile excreted were taken at predetermined intervals during 6 h. At 6 h animals were slaughtered and tissue samples of blood, liver, kidney, pancreas, spleen, heart, lung and pectoral muscle were taken. The values for OTC biliary elimination rate times were best fitted to a one-exponential equation. The maximum value for OTC biliary excretion rate (3.69+/-0.6 microg/min/kg) was reached at approximately 17.5 min (time to maximum concentration (tmax)). The first-order rate constant for the biliary excretion (k) and the half-life (t1/2) were 6.7x10(-3) min(-1) and 110.55 min, respectively. The mean value of area under the biliary excretion rate time curve (AUC) indicated that 839.77 microg/kg body weight (b.w.) were eliminated by the biliary route. The cumulative biliary excretion data indicated that approximately 4.20% of the dose was eliminated by this route, 3.28% being eliminated during the first 6 h and 0.92% thereafter. The highest mean concentrations were found in the kidney (35.82 microg/kg) and liver (16.77 microg/g). Significant differences were found between the concentrations of the various tissues studied. Plasma concentration was lower than that of the other tissues (except lung).     

Effect of dietary protein‐to‐energy ratio on reproduction in female redclaw crayfish Cherax quadricarinatus

The effect of eight diets with different protein‐to‐energy ratios (P–E ratio=10, 11, 14, 16, 18, 20, 22, 24 mg kJ^?1) on reproduction of female redclaw crayfish Cherax quadricarinatus was tested under laboratory conditions. After 75 days, there was a significant effect of the P–E ratio on final weight, spawning females and the number of juveniles per female. Using the broken‐line and quadratic equations, optimal values for the P–E ratio were: 16.0, 17.1 and 16.0 mg kJ^?1. The P–E ratio significantly affected protein and carbohydrate content and energy in the hepatopancreas. The broken‐line model indicated that the respective recommended values of the P–E ratio for these parameters were: 21.8, 16.7 and 18.6 mg kJ^?1. The concentration of carbohydrates and energy in muscle tended to significantly diminish as the P–E ratio increased. From broken‐line regression analysis, the recommended P–E ratio was 16.6 and 20.2 mg kJ^?1 respectively. No significant differences were found in survival, fecundity, vitellin content in eggs, protein and lipid content in muscle and lipids in the hepatopancreas. We concluded that, overall, a P–E ratio of 18±2 mg kJ^?1 is optimal for reproductive activity of female redclaw crayfish.     

Effects of Quillaja saponins on growth,feed efficiency,digestive enzyme activities and metabolism of common carp (Cyprinus carpio L)

Common carp were fed diets containing various levels of Quillaja saponins (QS) (0, 150, 300 and 450 mg kg^?1 dry diet) in a completely computerized respirometric system for 4 weeks. Fish fed diets containing QS exhibited significantly higher ABW and specific growth rate than did those fed the control diet; those fed diets containing QS 150 grew fastest but were not significantly different from those fed diets with QS 300 and QS 00450. All the utilization efficiency indices, namely food conversion efficiency (FCE), protein productive value and PG were increased by QS supplementation. There were no significant differences in the average routine metabolic rate between treatments, indicating that dietary QS at the levels tested were not toxic to the carp. Increases in amylase and trypsin specific activities were observed at QS 300 and QS 450. Enzymes of carbohydrate metabolism such as G6PDH, 6‐phosphogluconate dehydrogenase and pyruvate kinase were not significantly affected by dietary QS. Activities of the aerobic enzyme Cox and to a limited extent that of the anaerobic enzyme lactate dehydrogenase were significantly increased by dietary QS but the net effect was a shift towards aerobic metabolism, indicating absence of stress and favouring the anabolic processes. Thus, Quillaja saponin was beneficial as a feed supplement in the common carp.     

Chemical constituents and antioxidant activity of sweet cherry at different ripening stages

The development and ripening process of sweet cherry (Prunus avium L. cv. 4-70) on the tree was evaluated. For this purpose, 14 different stages were selected in accordance with homogeneous size and color. Some parameters related to fruit quality, such as color, texture, sugars, organic acids, total antioxidant activity, total phenolic compounds, anthocyanins, and ascorbic acid were analyzed. The results revealed that in sweet cherry, the changes in skin color, glucose and fructose accumulation, and softening process are initiated at early developmental stages, coinciding with the fast increase in fruit size. Also, the decrease in color parameter a was correlated with the greatest accumulation of total anthocyanins. Ascorbic acid, total antioxidant activity (TAA), and total phenolic compounds decreased during the early stages of sweet cherry development but exponentially increased from stage 8, which coincided with the anthocyanin accumulation and fruit darkening. TAA showed positive correlations (r(2) = 0.99) with both ascorbic acid and total phenolic compounds and also with the anthocyanin concentration from stage 8. Taking into account the reduced shelf life of sweet cherry and to ensure that these fruits reach consumers with the maximum organoleptic, nutritional, and functional properties, it is advisable to harvest sweet cherries at stage 12 of ripening.     

Presence of immunoglobulins and antigens in serum, lung and small intestine in Ascaris suum infected and immunised pigs

The immunodetection of local Ascaris suum antigens and local and systemic antibodies were analysed in pigs reinfected with eggs or immunized with the 14, 42 and 97 kilodalton (kDa) fractions from A. suum. Twenty-one Iberian pigs were divided in 7 groups of 3 pigs. Groups 1 and 2 were uninfected and challenge control groups, respectively. Groups 3 and 4 were infected weekly with increasing doses of A. suum eggs and Group 4 was additionally treated with pyrantel pamoate. Groups 5, 6 and 7 were immunised with the 14, 42 or 97 kDa fractions from adult worms, respectively. Groups 2-7 were challenged with 10,000 infective eggs. Animals of Groups 3 and 4 showed a pulmonary granulomatous reaction with moderate number of eosinophils and leukocytes, while Groups 5-7 presented higher number of cells, especially in animals immunized with the 42 kDa fraction. These immunized groups presented abundant deposition of Ascaris body fluid (BF) and body wall (BW) antigens as well as the 14 and 42 kDa fractions in the pulmonary and intestinal tissues, while lower deposition of antigens was observed in animals of Groups 3 and 4. The immunized pigs of Groups 5 and 6 showed the highest systemic IgG titres in serum and these antibodies were negatively correlated with the number of larvae recovered in the lungs, suggesting that the IgG response may have a protective function against the ascariosis. The highest concentrations of IgA-bearing cells were observed in animals of Groups 3 and 4 compared to the immunised pigs (Groups 5-7), suggesting that local IgA production may be involved in the protection against migrating larvae. The main localisations of IgA-bearing cells were the bronchial and peribronchial areas of lungs and the lamina propia of duodenum. Low numbers of local IgG-bearing cells were observed in all animals and no IgM-bearing cells were detected in the local tissues.     

Tuberculosis in alpaca (Lama pacos) on a farm in Ireland. 2. Results of an epidemiological investigation

Tuberculosis (TB), due to infection with Mycobacterium bovis was diagnosed in a flock of alpaca in Ireland in 2004. An epidemiological investigation was conducted to identify the risk of TB for farmed alpaca where TB is endemic, the origin of the infection, the potential for alpaca-to-alpaca transmission and appropriate control measures. The investigation focused on the alpaca flock (including the farm, animal movements and breeding, feeding and flock health practice), the disease episode (including animal disease events and subsequent control measures) and TB infection risk in the locality. The TB risk to alpaca is high in areas where infection is endemic in cattle and badgers and where biosecurity is inadequate. It is most likely that the source of infection for the alpaca was a local strain of M. bovis, present in cattle in this area since at least 2001. Genotyping of isolates identified a single variable number tandem repeat (VNTR) profile in both cattle and alpaca in this region. Although a tuberculous badger was also removed from the vicinity, bacterial isolation was not attempted. On this farm, infection in alpaca was probably derived from a common source. Alpaca-to-alpaca transmission seems unlikely. Two broad control strategies were implemented, aimed at the rapid removal of infected (and potentially infectious) animals and the implementation of measures to limit transmission. Tests that proved useful in detecting potentially-infected animals included measurement of the albumin-to-globulin ratio and regular body condition scoring. Skin testing was time consuming and unproductive, and early detection of infected animals remains a challenge. The flock was managed as a series of separate groupings, based on perceived infection risk. No further TB cases have been detected.