Effect of dietary lysine to crude protein ratio on performance of male Ross 308 broiler chickens

Two experiments were conducted to determine the effect of dietary lysine to crude protein ratio on performance of male Ross 308 broiler chickens. In each experiment the diets were isocaloric and isonitrogenous but with different lysine to crude protein ratios. A complete randomized design was used in both experiments, the starter (1-21 days) and grower (22-42 days) experiments. The three starter diets, based on lysine to crude protein ratios, were L(0) (0.055), L(1) (0.066) and L(2) (0.077), while grower diets were L(3)(0.047), L(4)(0.061) and L(5)(0.074). A quadratic type equation was used to determine ratios for optimum growth rate, feed conversion ratio, breast meat yield and breast meat nitrogen content. Dietary lysine to crude protein ratios of 0.066 and 0.077 supported optimum growth rate and feed conversion ratio, respectively, during the starter period. Dietary lysine to crude protein ratios of 0.073, 0.073, 0.069 and 0.079 supported optimum growth rate, feed conversion and breast meat yield and nitrogen content during the grower phase. Dietary lysine to crude protein ratio had no effect on diet intake and digestibility. The results indicate that at each phase a single dietary lysine to crude protein optimized both growth rate and feed conversion ratio. However, the ratio for optimum breast meat yield was lower than that for optimum growth rate and feed conversion ratio. These findings have implications on ration formulation for broiler chickens.

Productivity of Angora goats in the communal rangelands of Molimo-Nthuse area in Lesotho

Production parameters were determined for kidding, offtake and mortality rates, and milk production and composition of Angora goats in two communal agro-ecological zones, Mountains and Lowlands, of Molimo-nthuse area in Lesotho. True incidence rates and risk rates as used in dynamic populations were used to calculate the different production parameters. A completely randomized design was used to compare the differences between the two agro-ecological zones. Angora goats in the two agro-ecological zones produced milk similarly (p > 0.05) in amounts and composition. There were no significant (p > 0.05) differences in annual kidding, mortality and offtake rates between Angora goats kept in the Lowlands and those in the Mountains. However, high mortality rates and mortality risk rates were observed in both zones. Thus, the risk rates that suckling Angora goats would die within their first 6 months after birth were 28% and 34% for the Mountains and Lowlands, respectively. It is suggested that future emphasis should be on reducing kid mortality through better herding of the goats and improvement of pre- and post-partum nutrition of the doe in this communal livestock farming system.

Effects of stocking density and group size on the performance of white and brown Hyline layers in semi-arid conditions

The effect of housing two Hyline strains of commercial laying hens White Hyline (W-98) and Brown Hyline (Hyline Brown) at densities of 2, 3 or 4 per cage (1100, 733 or 550 cm2/hen, respectively) was investigated over 3 months. Hyline Brown layers gained more weight, laid more but lighter eggs, utilized feed more efficiently and had a lower mortality than W-98 layers. Housing birds 2 or 3 per cage resulted in greater body weight gain, higher egg production, heavier eggs, better feed conversion ratio and a lower mortality than housing them 4 per cage. There were significant interactions between strain and stocking density for egg production, egg weight, egg output and mortality. It is suggested that for egg production in semi-arid areas Hyline Brown hens could be used and housed at a density of 733 cm2/hen.

Effects of genetic and environmental factors on pre-weaning and post-weaning growth in West African crossbred sheep

Effects of genetic and environmental factors on pre-weaning and post-weaning growth were studied in West African crossbred sheep. Effects of lamb genotype (7/8 Sahelian-1/8 Djallonké, 3/4 Sahelian-1/4 Djallonké and 1/2 Sahelian-1/2 Djallonké; hereafter denoted 7/8Sa, 3/4Sa and 1/2Sa, respectively), parity, type of birth, sex of lamb and year-season of lambing on birth weight, weaning weight, 8-month weight and pre- and post-weaning growth rates were determined. At birth 7/8Sa and 3/4Sa lambs were heavier (p < 0.01) than 1/2Sa lambs. Lambs born to first-parity ewes were lighter (p < 0.01) at birth than lambs of older ewes. At weaning and 8 months of age, lambs born to fourth-parity ewes were heavier (p < 0.05) than those born to ewes of the other parities. Parity did not have any significant effects on pre-weaning growth rate. Lambs born in the rainy season of 2001 were significantly heavier at birth and at 8 months of age than those born in the dry season of 2001/02, but there was no difference between the two groups at weaning. Pre-weaning growth rate was significantly faster in lambs born in the dry season of 2001/02 but the reverse was true for post-weaning growth rate.

Genetic parameter estimates for body weight in local Venda chickens

Genetic parameters were estimated for Venda chicken body weights at hatching, and at 4 weeks, 10 weeks and 21 weeks of age. A single-trait animal model with restricted maximum-likelihood procedures was used. Random effects were additive direct and maternal genetic, common environmental and error. The heritability estimates for direct effects were 0.36, 0.25, 0.41 and 0.22 for hatch, 4 weeks, 10 weeks and 21 weeks, respectively. The maternal effects were estimated at hatch and 4 weeks of age and were not present at later ages. Common environmental effects disappeared with increasing age. There was an antagonistic relationship between direct and maternal effects. The results show potential for genetic improvement of indigenous Venda chickens through selection. Maternal effects should be considered if selection is carried out at early ages.

Lowering the dose of hydroxyurea minimizes toxicity and maximizes anti-HIV potency

The goal of this study was to optimize the hydroxyurea dosage in HIV-infected patients, and to minimize the toxicity and maximize the antiviral efficacy of the hydroxyurea-didanosine combination. In a randomized, open-label study (RIGHT 702, a multicenter trial performed in private and institutional practices), three daily doses (600 microg, 800-900 microg, and 1200 microg) of hydroxyurea were administered in combination with didanosine and stavudine to 115 chronically HIV-infected patients, one-third antiretroviral drug naive, with viremia between 5000 and 200,000 copies/ml regardless of CD4+ cell count. The primary efficacy end point was the proportion of patients with plasma HIV-1 RNA levels below 400 copies/ml after 24 weeks of therapy. In the RIGHT 702 intent-to-treat population the lowest (600 mg) dose of hydroxyurea was better tolerated, associated with fewer adverse events, and more potent by all efficacy parameters, including the primary end point (76 versus 60% patients with viremia<400 copies/ml at week 24 for the 600-mg and 800- to 900-mg dose groups, respectively; p=0.027), the mean area under the curve (60.3 versus 65.8; p=0.016), and the mean log10 decrease (-1.95 versus -0.77; p=0.001). Patients receiving 600 mg of hydroxyurea daily also had the highest CD4+ cell count, CD4+/CD8+ cell ratio, and lowest CD8+ cell count and percentage (p=0.035). The RIGHT 702 trial provides an explanation for the increased toxicity and decreased efficacy of hydroxyurea when it was used at high dosage (1200 mg daily). At the optimal dosage of 600 mg daily, hydroxyurea, in combination with didanosine, deserves reevaluation for the long-term management of HIV/AIDS worldwide, because of its excellent resistance profile, durability, and affordability.

Estimation of Genetic Parameters and Variance Components for Growth Traits of Nguni Cattle in Limpopo Province, South Africa

Estimates of (co)variance and genetic parameters of birth, weaning (205 days) and yearling (365 days) weight were obtained using single-trait animal models. The data were analysed by restricted maximum likelihood, fitting an animal model that included direct and maternal genetic and permanent environmental effects. The data included records collected between 1976 and 2001. The pedigree information extended as far back as early 1960s. The heritabilities for direct effects of birth, weaning and yearling weights were 0.36, 0.29 and 0.25, respectively. Heritability estimates for maternal effects were 0.13, 0.16 and 0.15 for birth, weaning and yearling weights, respectively. The correlations between direct and maternal additive genetic effects were negative for all traits analysed. The results indicate that both direct and maternal effects should be included in a selection programme for all the traits analysed.

Relationships between Longevity and Linear Type Traits in Holstein Cattle Population of Southern Africa

Relationships between longevity and linear type traits were estimated using data on 34,201 cows with lifetime information and linear type scores. The longevity trait considered was the number of lactations initiated and the linear type traits were rump height, body depth, angularity, rear udder height, fore udder attachment, udder depth, fore teat placement and fore teat length. Fixed effects included in the models were herd year, season of calving and herd-date of classification-classifier and days in milk. Age at first calving and age at classification were included as linear and quadratic covariates. Heritability estimates were low for longevity and moderate for most type traits except rump height and fore teat length. All the phenotypic correlations between longevity and the linear type traits were slightly positive (0.01 to 0.09) except the relationships with rump height and fore teat length which were -0.01 and -0.02, respectively. Genetic correlations between longevity and udder traits as well as angularity were moderate to high and positive (0.22 to 0.48). The only notable negative genetic correlations were longevity with body depth and fore teat length (-0.15 and -0.07, respectively). The genetic correlations suggest that selection for udder traits and angularity should improve longevity in the Holstein cattle population.

Changes in vegetation and soil characteristics in coastal sand dunes along a gradient of atmospheric nitrogen deposition

A field survey was conducted to detect signals of atmospheric nitrogen (N) in 11 dune systems along a nitrogen deposition gradient in the United Kingdom. In the mobile and semi-fixed dunes, above-ground biomass was positively related to N inputs. This increase was largely due to increased height and cover of Ammophila arenaria. In the long term, this increased biomass may lead to increased organic matter accumulation and consequently accelerated soil development. In the fixed dunes, above ground biomass also showed a positive relationship with N inputs as did soil C : N ratio while soil available N was negatively related to N inputs. Plant species richness was negatively related to N inputs. In the dune slacks, while soil and bulk vegetation parameters showed no relationship with N inputs, cover of Carex arenaria and Hypochaeris radicata increased. Site mean Ellenberg N numbers showed no relationship with N deposition either within habitats or across the whole dataset. Neither abundance-weighting nor inclusion of the Siebel numbers for bryophytes improved the relationship. The survey reveals that the relationships of soil and vegetation with atmospheric N deposition vary between sand dune habitats but, despite this variability, clear correlations with N inputs exist. While this survey cannot establish causality, on the basis of the relationships observed we suggest a critical load range of 10 - 20 kg N ha(-1) yr(-1) for coastal sand dunes in the UK.

Finding and using rural aging data: an international perspective

This article reports on a workshop in which participants identified sources of data on rural aging. Such sources are typically part of larger data collection efforts or special aging studies with large rural components. Finding and using data on rural aging are not only two different processes but they also face somewhat different obstacles and the solutions are likewise different. The workshop addressed both of these issues. Participants shared many innovative and creative means for collecting, finding and adapting more general data sources, and analyzing and using these data, to further our understanding of rural aging phenomena.

The bispectral index monitor: a new tool for air medical personnel

The bispectral index monitor (BIS) is commonly used in the operating room to help anesthesiologists quantitate the level of anesthesia. The BIS has been shown to reduce the incidence of anesthetic overuse and decrease costs. The device has made its way into critical care areas, where it has proven effective in monitoring sedation levels, specifically in reducing the incidence of oversedation. This article explores the possibility of using the monitor in the air medical environment.

A comparison of medication errors between two storage sites

This prospective single-blinded study aimed to compare the types of medication errors and medication error rates of two medication delivery systems. The setting was a 30 bed surgical ward that was divided into two identical areas. In one area medications were stored and issued in a ward bay workstation immediately outside the patients' rooms. The alternate area used a medication trolley at the patients' bedside. Three hundred and forty opportunities for errors were observed using five nurse educators. Twenty administration errors (5.8% error rate) and two dispensing errors (0.6% error rate) were detected. A statistically significant difference was found between the two systems, where four errors occurred from the medication trolley (2.6% error rate), and fifteen errors occurred from the ward bay (9.2% error rate). These results suggest that medications were less likely to be omitted and more likely to be given on time when they were issued at the patient's bedside using the medication trolley.