Search

The shallow aquifer beneath the Western Snake River Plain (Idaho, USA) exhibits widespread elevated arsenic concentrations (up to 120 μg L−1). While semi-arid, crop irrigation has increased annual recharge to the aquifer from approximately 1 cm prior to a current rate of >50 cm year−1. The highest aqueous arsenic concentrations are found in proximity to the water table (all values >50 μg L−1 within 50 m) and concentrations decline with depth. Despite strong vertical redox stratification within the aquifer, spatial distribution of aqueous species indicates that redox processes are not primary drivers of arsenic mobilization. Arsenic release and transport occur under oxidizing conditions; groundwater wells containing dissolved arsenic at >50 μg L−1 exhibit elevated concentrations of O2 (average 4 mg L−1) and NO3 (average 8 mg L−1) and low concentrations of dissolved Fe (

The goal was to evaluate acoustic analysis as a means to monitor and quantify chewing behaviour, and to estimate DM intake of forages with a wide range of water and fibre content. Each of three Angus steers (284–316 kg of body weight) was fed 32 treatments resulting from the factorial combination of four amounts ( i.e. 75, 150, 225 and 300 g dry matter, DM), two particle lengths ( i.e. chopped or whole), two water contents ( i.e. fresh or hay), and two species ( i.e. grass or alfalfa). Behaviour was videotaped and chewing sound was recorded using a microphone attached to the steers foreheads. Intake rate of DM was higher for alfalfa versus grass higher (33.0 ± 2.03 versus 28.7 ± 2.04 g DM/min), and lower in fresh forages versus hays (28.0 ± 2.04 versus 33.7 ± 2.04 g DM/min). Fresh forage was chewed more than hay (3.1 ± 0.19 versus 2.4 ± 0.19 chews/g DM) demonstrating that chewing was primarily affected by water content of forage. Alfalfa hay was chewed less than grass hay, but fresh grass and fresh alfalfa did not differ from each other and required more chewing than fresh forages. The impact of forage internal water in chewing was clear, since chews per g of neutral detergent fibre (NDF) differed among the forages, but for fresh alfalfa (the forage with the most water and the least NDF), it was much higher than for the rest. There was little evidence of an impact of particle size on chewing behaviour, probably because all forages had very long particles. Of the variation of energy in chewing sound (E), 66% was explained by DM intake (DMI). The relationship between E and DMI was linear, and the slope was 28% higher for fresh forages versus hays (P=0.033). Volume of chewing sound explained the most variation in E/DMI, and it was higher for fresh forage versus hays, whereas chews/DMI was the component of E/DMI most affected by forage characteristics. The DMI was estimated accurately based on easily observable behavioural and acoustic variables. Number of chews, cumulative sound energy and forage moisture ( i.e. fresh versus hay) were the most important predictors. The prediction error in cross-validation was 27.3 g DM (coefficient of variation = 16%, R 2 = 0.89). Acoustic analysis yields more useful information than simple the number and rate of chewing, and should be further developed as method to research and monitor chewing behaviour of ruminants.

Animal source foods (ASF) can provide micronutrients in greater amounts and more bioavailable forms compared to plant source foods, but their intake is low in many poor populations. However, the impact of ASF on micronutrient status of undernourished populations has not been assessed. Supplemental meat (60-85 g/d), milk (200-250 mL/d) or energy (isocaloric with the meat and milk, 240-300 kcal/d) were randomly assigned to 555 undernourished school children aged 5-14 y in a rural malaria-endemic area of Kenya, at one school meal daily for one school year. Blood and stool samples were collected at baseline and after 1 y to assess stool parasites, malaria, hemoglobin, serum or plasma C-reactive protein, ferritin, iron, zinc, copper, vitamin B-12, folate and retinol, and erythrocyte riboflavin. At baseline, there was a high prevalence of micronutrient deficiencies (iron, zinc, vitamins A and B-12 and riboflavin), yet plasma ferritin was low in few children, and none had low serum copper. At the end of the year of supplementation, plasma vitamin B-12 concentrations were significantly increased in children fed the Meat or Milk meal; prevalence of severe plus moderate deficiency fell from 80.7% at baseline to 64.1% in the Meat group and from 71.6 to 45.1% in the Milk group, respectively. No significant improvement was observed in the status of other micronutrients compared to the Energy and Control groups, although malaria and other infections may have obscured effects. Supplementation with small amounts of meat or milk reduced the high prevalence of vitamin B-12 deficiency in these children.

To alleviate poverty in developing countries, economies must grow. Without the necessary investments in human capital, national economic growth may not lead to poverty alleviation and socioeconomic development, nor be sustainable. Economic growth that leads to poverty alleviation is fueled by the creative and physical capacities of people. The impact of micronutrient malnutrition is established early in life, leading to growth stunting, lower cognitive abilities, lethargy and poor attention, and greater severity and rates of infection. These effects limit educational progress, physical work capacity and life expectancy, thereby reducing individual lifetime productivity and the aggregate ability of the population to enhance its well-being and participate in national and global markets. The diets of the poor are largely cereal-based, monotonous and lacking in diversity and micronutrients. Animal source foods (ASF) have been an important factor in human evolution, a component of what was an historically diverse diet and an important source of micronutrients. Poverty and micronutrient malnutrition positively influence each other. This poverty micronutrient malnutrition (PMM) trap requires outside inputs to change the state of development in developing countries. Nutrition interventions have been excellent investments in development. More productive interaction between agricultural scientists and nutritionists, supported by a strong federal agenda for development, is needed to break the PMM trap. In the end, food is the means by which nutrients are delivered. Food-based approaches will require long-term commitments, but are more likely to be sustainable because they are part of a development process that leads to long-term economic growth. J. Nutr. 133: 3879S-3885S, 2003.

Grazinglands, vegetated land that is grazed or has the potential to be grazed by wild and/or domestic ungulates, occupy about half of the world’s surface, provide livelihoods to almost one billion people, and constitute a major component of the global carbon stock and cycle. Grazinglands have significant potential for mitigation of climate change in the short term, and management practices that lead to mitigation are fairly well known. However, the degree to which this mitigation potential is realized pivots on our ability to design cost-effective protocols to promote the implementation of such management practices. In order to create efficient protocols we need a deeper and more precise knowledge of the processes and factors that affect greenhouse gas (GHG; mainly CO 2 , N 2 O, and CH 4 ) fluxes and carbon (C) stocks in grazinglands.

The technique of grazing cut sods was used in combination with sound and video recording to examine the feasibility of using small-scale depletion curves derived from stall trials to estimate forage intake of cattle at the pasture. Setaria lutescens sods were grazed for a variable number of bites to generate patch depletion curves. Depletion curves characterize forage intake as a function of the number of bites taken at a single feeding station. Thus, the method agrees with a hierarchical approach to foraging and it could be used as a basis for scaling up food intake measurements to larger spatial scales. Two sod experiments were carried out, with the second experiment as a validation for predictions of intake. A field experiment was carried out to validate the predictions from the sod experiments with respect to both the amount and the rate of intake. Bite weight was largely determined by initial sward height and depletion level. Cumulative dry matter intake from the sods was well described by a rectangular hyperbola including the variables of number of bites and sward height. Bulk density added little to the explained variation, but was an important factor to account for the dry matter intake on short, dense sods from the second experiment. Feeding time could be explained to a great extent by the number of bites and chews taken, both in the sod and in the field experiments. However, the animals were substantially faster when grazing in the field than on the sods due to a relatively smaller chewing effort. The estimate of bite weight in the field based on the sod depletion curves was validated by an independent estimate derived from the chew to bite ratio. Bite weight estimates that ignored feeding station depletion were significantly greater than the independent estimates. We conclude that the sod grazing technique is an adequate tool to investigate food intake and forage depletion by grazing. It shows promise as a tool to explicitly scale up of foraging behaviour from the level of the feeding station to that of larger patches.

Social organization and space use patterns of sexually sized dimorphic Nubian ibex (Capra ibex nubiana) were studied for 26 months in the northern Negev Desert, Israel. The main social units were: female/kid groups that also contained young males up to 3-years-old, immature male (4–6-years-old), mature male (more than 6-years-old), and mixed groups. Mature males and females were in separate groups except during rut, when mature males moved into areas occupied by females and were equally likely to be seen in female/kid, mature male, or mixed groups. Outside the rut, 89% of female sightings were in 4 ha quadrats in which no mature males were seen, but there was a dramatic increase in spatial overlap of adult males and females during the rut as the males moved into the same areas as females. Young males were found almost exclusively in female/kid groups (>90% of observations), but as body size of growing males surpassed that of females, they were more frequently associated with other groups. The pattern of sexual segregation of groups and space, and the age at which males left groups dominated by females and kids, is consistent with a nutritional hypothesis of foraging patterns and social organization for sexually dimorphic herbivores.

The effects of sward structure and bite weight ( W ) on bite rate in cattle ( Bos taurus ) were examined to explain the behavioural components of handling time. Three oesophageally fistulated steers grazed homogeneous, hand-constructed swards of Paspalum dilatatum Poir. or Medicago sativa L., in a sward area of approximately 0.36 m 2 , for 60–212 s. Three types of jaw movements (JM) were distinguished: manipulative JM that gather herbage into the mouth, chewing JM, and compound JM that manipulate fresh herbage and chew herbage already in the mouth within one cycle of opening and closing of the jaws. Intake rate ( I , g min −1 ) was a discontinuous asymptotic function of W: I = W max (0.0337,0.0201 + 0.0095 ∗ W) . Sward height and bulk density did not significantly affect I beyond the effects of W . Time per bite was 2.0 s when W ≈ 1.29 g, and increased linearly with W when W >1.29 g. Linear regression of time per bite on total number of JM explained 96% of the variance. A non-linear relation between total JM per bite and W comprised a linear relation between total chews per bite and W , and a constant number of total manipulative JM per bite. When W increased up to c . 1.5 g, chewing requirements were met by compound JM. Above W of 1.5 g, the overlap of chewing and manipulation reached a maximum, so total JM increased with W . The importance of compound JM and the potential for overlap between chewing and searching are discussed in the context of foraging models.

To investigate the digestive kinetics and fiber digestion of great apes, we conducted digestion trials on chimpanzees (Pan troglodytes) with diets of two fiber levels, one containing 34% neutral detergent fiber (NDF) and the other 14% NDF. Chimpanzees exhibited a response to fiber similar to that of humans. First, increases in the fiber concentration of the diet decreased mean transit time (MTT), hindgut turnover time (T) and the digestibility of fiber. Second, differences in MTT and T between the treatments and animals explained most of the variability in the digestibility of fiber components. Third, consistent with human data, the fiber marker passed more slowly than the liquid marker only when the high fiber diet was consumed. Fourth, individual variability, as in humans, was a significant factor affecting digestion and passage. Fifth, the MTT of chimpanzees was longer than that of humans. This result may be due to the apes' larger hindgut. In comparison with other hominoids, humans have smaller volumes in the gastrointestinal tract and hindgut. The gut proportions of modern humans, in combination with evidence from the fossil record, indicate that during its evolution the human lineage was able to overcome nutritional constraints imposed on body size increases in the great apes. We suggest that this advance was achieved through technological and social innovations that permitted early humans to achieve larger body size without lowering dietary quality.