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Household surveys are one of the most commonly used tools for generating insight into rural communities. Despite their prevalence, few studies comprehensively evaluate the quality of data derived from farm household surveys. We critically evaluated a series of standard reported values and indicators that are captured in multiple farm household surveys, and then quantified their credibility, consistency and, thus, their reliability. Surprisingly, even variables which might be considered ‘easy to estimate’ had instances of non-credible observations. In addition, measurements of maize yields and land owned were found to be less reliable than other stationary variables. This lack of reliability has implications for monitoring food security status, poverty status and the land productivity of households. Despite this rather bleak picture, our analysis also shows that if the same farm households are followed over time, the sample sizes needed to detect substantial changes are in the order of hundreds of surveys, and not in the thousands. Our research highlights the value of targeted and systematised household surveys and the importance of ongoing efforts to improve data quality. Improvements must be based on the foundations of robust survey design, transparency of experimental design and effective training. The quality and usability of such data can be further enhanced by improving coordination between agencies, incorporating mixed modes of data collection and continuing systematic validation programmes.
The objective was to compare the performance of the updated Charlson comorbidity index (uCCI) and classical CCI (cCCI) in predicting 30-day mortality in patients with Staphylococcus aureus bacteraemia (SAB). All cases of SAB in patients aged ⩾14 years identified at the Microbiology Unit were included prospectively and followed. Comorbidity was evaluated using the cCCI and uCCI. Relevant variables associated with SAB-related mortality, along with cCCI or uCCI scores, were entered into multivariate logistic regression models. Global model fit, model calibration and predictive validity of each model were evaluated and compared. In total, 257 episodes of SAB in 239 patients were included (mean age 74 years; 65% were male). The mean cCCI and uCCI scores were 3.6 (standard deviation, 2.4) and 2.9 (2.3), respectively; 161 (63%) cases had cCCI score ⩾3 and 89 (35%) cases had uCCI score ⩾4. Sixty-five (25%) patients died within 30 days. The cCCI score was not related to mortality in any model, but uCCI score ⩾4 was an independent factor of 30-day mortality (odds ratio, 1.98; 95% confidence interval, 1.05–3.74). The uCCI is a more up-to-date, refined and parsimonious prognostic mortality score than the cCCI; it may thus serve better than the latter in the identification of patients with SAB with worse prognoses.
Dual-purpose (milk and beef) farms in the tropics are characterised by 1) a high variability of nutritional management systems, and 2) their flexibility to adapt to changing conditions. An appropriate characterisation and classification of these systems is necessary to determine efficient and sustainable resource management strategies according to the different goals or productive orientation of the farms. A prospective study for characterising the nutritional management systems of dual purpose farms in Costa Rica was carried out. The dynamics of the farms, in terms of management intensity and productive orientation, are described and discussed.
The aim of using any in vitro method is to obtain a good description of the nutritional value of forages as they are fed, which in most cases is on a fresh basis. The in vitro gas production technique has the potential to characterise fermentation pattern of the carbohydrate fractions of forages, and has been used extensively with forage material that has been dried and ground through a 1mm screen. The objective of the present study was to compare the fermentation patterns of fresh and dry forage.
The growth performance of youngstock has a double effect on the general productivity of dual purpose farms. First, it directly influences the beef outputs of the farm, and second; it has an indirect effect on the length of the non-productive period of the replacement heifers and their subsequent milk production ability. The latter effect has been well documented on dairy heifers in both temperate and tropical conditions. The growth performance of youngstock is dependent of the management intensity and productive orientation of the farm. This paper shows the effect of a series of nutritional factors and farming characteristics on the pre-weaning growth performance of youngstock in eighteen dual purpose farms in Costa Rica.
This paper discusses some of the unique aspects of the interactions of livestock with the natural resources base. It argues the nature of these interactions make the use of a systems approach of particular importance when planning and executing livestock research if it is to be of any relevance to farmers in developing countries. The key issues are illustrated in two contrasting case studies.
In Nepal, shifts in land use patterns have led to marked changes in the availability and use of fodder resources. Farmers indicate that they are no longer able to use these optimally. Fodder from at least 90 different types of tree (some of which have yet to be properly classified botanically) are used to supplement the diets of buffalo, cattle and goats during dry seasons when food is in short supply. The nutritive value of each of these is affected by a wide range of management and environmental factors. Furthermore, diet selectivity means that fractions consumed differ markedly amongst both tree species and classes of livestock. It is clearly not feasible for researchers to evaluate this diversity using existing in vitro or in vivo indicators of nutritive value. Initial studies suggest that this variability is implicitly catered for in farmers' own assessments of relative nutritive values. A mechanistic understanding of this indigenous technical knowledge and the development of appropriate techniques for integrating it with models of the biological responses of animals to nutrients might, therefore, allow more effective assessment of strategies for tree fodder utilization.
Highland dairy systems in the humid tropics of Costa Rica (3000+ mm/year rainfall) could be very productive but suffer from a substantial dependence on imported inputs. Concentrate use is very high causing substantial underutilization of grazed pasture (the local resource), which is available year-round under these high-rainfall conditions. Over-supplementation with protein, which is the most expensive nutrient in the diet, at levels in excess of 200% of the requirement has been reported widely in these regions. Farmers want new strategies that enable them to manage their land and other resources in an alternative way, in order to be less dependent on grains and other imports. A decision-support system based on simulation and multiple criteria models representing a dairy farm has enabled the design and development of such strategies. Using this approach, farmers' objectives can be incorporated with a holistic understanding of the farming system in terms of management practices that will permit demand-driven animal production research at the farm level.
Smallholder dairy production in Kenya is one of the developing world’s success stories. Kenya's improved dairy cattle herd of more than 3 million is the largest in Africa, and significantly is held mostly by smallholders. As a result, dairy production is a major part of the agricultural sector and an important source of livelihoods for at least an estimated 600,000 smallholder farm families in Kenya (Omore et al., 1999). Compared to its neighbours, the country has a welldeveloped dairy production and processing industry, and the country has broadly managed to be self-reliant in dairy products, so that except during extreme dry years, imports are negligible.
In order to understand and ultimately predict the voluntary intake and performance of ruminants, it is necessary to know the nutritional value of foods. Most recent systems for predicting nutrient supply are dynamic in nature and characterize foods in terms of the quantities of available nutrients and their potential rates of supply. The in vitro gas production system has been used to characterize the carbohydrate fraction of foods in this manner. For the technique to be able to do this, two assumptions must be satisfied. First, that the rate of fermentation is limited by characteristics of the food and secondly that the pattern of gas production correlates closely with the pattern of food fermentation.Low microbial activity within the system could invalidate both assumptions since it could (i) limit the rate of food fermentation, thus not allowing the potential rate determined by the physical and chemical nature of the food to be measured and (ii) result in partition of food carbohydrate into new microbial matter, thus reducing the amount of volatile fatty acids and hence gas produced per unit of food fermented.
The aims of this study were mathematically to simulate food fermentation within an in vitro system and to use this representation to investigate the potential effects of variation in microbial activity on the characterization of foods.
The paper presents the main findings of a set of comparative milk sector surveys carried out in Kathmandu (Nepal), Nairobi (Kenya) and Santa Cruz (Bolivia). The surveys assessed changes in demand, supply and marketing of milk and milk products over a ten to fifteen year period to 2001. The paper considers demand for milk and milk products, changes in milk supply and trading pathways, the policy frameworks, changes in demand and market share, and growth in the sector and poverty reduction. The policy implications for propoor development of the milk sector are discussed.
There is increasing demand to obtain fast and accurate dynamic nutritional information from forages. Near-infrared reflectance spectroscopy (NIRS) offers the possibility for obtaining such information for a range of nutritional constituents of foods. Herrero et al. (1996 and 1997) calibrated in vitro gas production measurements of a single grass species by NIRS. There would be greater practical benefit if the gas production predictions could be obtained using calibrations derived from a wide range of plant species, since a single equation could be used for all forages. The objective of this study was to investigate if in vitro gas production measurements of a broad based sample population could be calibrated by NIRS.
Following the development of the Menke technique in 1979, the measurement of gas production in vitro has become increasingly popular for investigating the kinetics of rumen fermentation. The aim of this study was to compare the gas production profiles for three foods using two in vitro gas production techniques; the Menke et al. (1979) technique (MT) and the pressure transducer technique (PTT) (Theodorou et al., 1994). Both techniques involve recording gas production throughout the incubation of a food sample with rumen fluid. The MT incubations are made in gas-tight syringes where the volume of gas produced causes the plunger to move up the syringe barrel. The PTT involves measuring gas production in fermentation bottles using a pressure transducer and syringe assembly to measure the pressure and corresponding gas volume. As the medium to rumen fluid ratios also differ between techniques; 2:1 in the Menke technique and 9:1 in the PTT, both ratios were investigated in this study.
Extrapolate (EX-ante Tool for RAnking POLicy AlTErnatives) is a decision support tool to assess the impact of policy measures on different target groups. It is designed to serve as a “filter” that, given the broad characteristics of the population, allows the user to sift through different policy measures to assess ex ante the broad potential impacts of these before deciding to look at particular policy options in more detail. Extrapolate models, in a very simple way, the impact of changes on constraints facing potential beneficiary groups, and how these may affect outcomes and their livelihood status. Extrapolate now makes use of mapping facilities from another decision-support tool, PRIMAS (Poverty Reduction Intervention Mapping in Agricultural Systems), that allows the user to match characteristics of particular technological options and constraints with the spatial characteristics of particular target groups in the landscape.
Food eaten by a ruminant firstly undergoes microbial fermentation within the rumen. Nutritionally important characteristics of the food are the rate and extent of fermentation of its carbohydrate fraction, which can both be estimated using the in vitro gas production technique. The single greatest source of uncontrolled variation in any in vitro rumen fermentation system is the rumen fluid; curves produced from gas production data were influenced significantly by the variation in microbial activity between days (Menke and Steingass, 1988; Beuvink et al, 1992). A more reliable measure of rumen fluid activity is needed. The objective of this study was to determine whether the frequency of sampling of rumen fluid affected the microbial activity and subsequent fermentation.
Brachiaria spp. pastures, specially B. decumbens, cover an area of 400 thousand ha in Santa Cruz, Bolivia. They comprise the basal diet for ruminants in dual-purpose and small-holder dairy systems of the region (Herrero et al. 1999). Therefore, an important portion of the animal production is conditioned by the amount and quality of these pastures and their intake. Knowledge of pasture intake is crucial for formulating bio-economically feasible feeding systems for ruminants. The objective of this work was to measure intake of Brachiaria spp pastures using alkanes as markers and to quantify pasture intake differences between dry and lactating cows.
IR spectroscopy in the range 12–230 μm with the SPace IR telescope for Cosmology and Astrophysics (SPICA) will reveal the physical processes governing the formation and evolution of galaxies and black holes through cosmic time, bridging the gap between the James Webb Space Telescope and the upcoming Extremely Large Telescopes at shorter wavelengths and the Atacama Large Millimeter Array at longer wavelengths. The SPICA, with its 2.5-m telescope actively cooled to below 8 K, will obtain the first spectroscopic determination, in the mid-IR rest-frame, of both the star-formation rate and black hole accretion rate histories of galaxies, reaching lookback times of 12 Gyr, for large statistically significant samples. Densities, temperatures, radiation fields, and gas-phase metallicities will be measured in dust-obscured galaxies and active galactic nuclei, sampling a large range in mass and luminosity, from faint local dwarf galaxies to luminous quasars in the distant Universe. Active galactic nuclei and starburst feedback and feeding mechanisms in distant galaxies will be uncovered through detailed measurements of molecular and atomic line profiles. The SPICA’s large-area deep spectrophotometric surveys will provide mid-IR spectra and continuum fluxes for unbiased samples of tens of thousands of galaxies, out to redshifts of z ~ 6.
The present study aimed to evaluate trace mineral status of organic dairy herds in northern Spain and the sources of minerals in different types of feed. Blood samples from organic and conventional dairy cattle and feed samples from the respective farms were analysed by inductively coupled plasma mass spectrometry to determine the concentrations of the essential trace elements (cobalt (Co), chromium (Cr), copper (Cu), iron (Fe), iodine (I), manganese (Mn), molybdenum (Mo), nickel (Ni), selenium (Se) and zinc (Zn)) and toxic trace elements (arsenic (As), cadmium (Cd), mercury (Hg) and lead (Pb)). Overall, no differences between organic and conventional farms were detected in serum concentrations of essential and toxic trace elements (except for higher concentrations of Cd on the organic farms), although a high level of inter-farm variation was detected in the organic systems, indicating that organic production greatly depends on the specific local conditions. The dietary concentrations of the essential trace elements I, Cu, Se and Zn were significantly higher in the conventional than in the organic systems, which can be attributed to the high concentration of these minerals in the concentrate feed. No differences in the concentrations of trace minerals were found in the other types of feed. Multivariate chemometric analysis was conducted to determine the contribution of different feed sources to the trace element status of the cattle. Concentrate samples were mainly associated with Co, Cu, I, Se and Zn (i.e. with the elements supplemented in this type of feed). However, pasture and grass silage were associated with soil-derived elements (As, Cr, Fe and Pb) which cattle may thus ingest during grazing.
Effective tools for male contraception are important in the control of reproduction in animal populations. The aim of the present study was to evaluate the effects of active immunization against gonadotropin-releasing hormone (GnRH) on male reproductive function assessing testicular morphological changes and serum-gonadotropin levels in pre-pubertal rabbits, guinea pigs and ram lambs. An anti-GnRH vaccine was developed by linking a GnRH-homologous molecule to a tetanus clostridial toxoid (Al(OH)3 coadjuvant). After vaccination protocols testicular morphometry, histopathological alterations and endocrine responses (FSH, LH, testosterone and cortisol serum levels) were evaluated. Testicular volume was significantly reduced in vaccinated animals with respect to the control group in rabbits, guinea pigs and ram lambs (P<0.05 to P<0.001). The anti-GnRH vaccine generated a reduction in testicular volume of 15-, 27- and 11-fold, respectively. Tubule diameters decreased in the vaccinated group with respect to the control ~2.0-, 1.2- and 3.5-fold, respectively (P<0.001). Tubule, intertubular and lumen volumes significantly decreased in vaccinated rabbits (P<0.05), guinea pigs and ram lambs (P<0.01). Vaccinated animals of the three species showed significant reductions in spermatogonial numbers (10- to 40-fold; P<0.01). Sperm was absent in all seminiferous tubules of all rabbits, and most individuals of guinea pigs (80%) and ram lambs (60%). No significant differences were observed between vaccinated and control groups regarding FSH and LH during the experiments in the three experimental species/models used. Testosterone, however, was only significantly lower (~22-fold, P<0.01) in vaccinated rabbits. In conclusion, the present study demonstrated that pre-pubertal active immunization against GnRH leads to endocrine disruption and marked differences on testicular morphometry, development and activity among lagomorphs, hystricomorphs and ovine species with species-specific sensitivity regarding the anti-GnRH immune response.
The 0.5m refracting telescope of the Van Vleck Observatory has been active in the determination of trigonometric parallaxes since its first observations in 1922. Its lenses were ground by C.A.R. Lundin of the Alvan Clark Co. for photographic use. Coma was minimized across the field and vignetting was also kept to a minimum. Partly as a consequence the focal curve is very steep in the blue and green regions of the spectrum, as is shown in Fig. 1. A Wratten No. 12 minus blue filter is used to filter out all wavelengths to the blue of about 5200 å. The region between 5200 å and 6000 å is very flat with the focal plane varying over a range of about one millimeter. Towards the red region it steepens, although not enough to impair images on photographic plates of emulsion types 103a-D and IIIa-F, the two in widespread use in recent years.
We present spectral descriptions based on high-resolution spectrograms of central stars of planetary nebulae, obtained with the ESO 3,6-m telescope + CASPEC (Cassegrain Echelle Spectrograph). We make preliminary determinations of stellar photospheric metal abundances, using non-LTE model atmospheres and non-LTE line formation calculations.