Intake and digestion of barley straw by sheep given expelled groundnut meal with different amounts of calcium

Summary Six wether sheep were used in a 6×6 latin square experiment to study the effect of calcium intake on intake and digestibility of barley straw fedad libitum with low and high oil groundnut meal. The level of added calcium ranged from 1.6 to 3.0 g/day for the low oil and 6.4 to 10.4 g/day for the high oil diet. Each experimental period was of 21 days duration which comprised 14 days for adaption to the diet followed by a sevenday collection. The amount of added calcium had a significant effect only with the high oil groundnut meal. The digestibility of crude fibre in diets which contained this meal was significantly increased (p<0.05) when the amount of added calcium was raised from 6.4 to 8.0 g/day. The sheep showed a marked adaptation to the diets which was manifested as a highly significant increase (p<0.001) in straw intake as the trial progressed. There was a significant difference (p<0.05) between animals in intake and digestibility of some dietary constituents. This was shown particularly by one animal whose intake was substantially greater but whose digestive ability was appreciably less than the other five. The nitrogen retention by the sheep on the six diets differed considerably between the two types of groundnut meal. It was higher when the high oil meal was fed and this difference was mainly due to a smaller excretion of urea.

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Sumario Los ensayos de digestibilidad y pruebas de balance fueron llevadas a cabo en 6 ovinos castrados con el fin de estudiar el efecto del suplemento de calcio sobre la ingestión y digestibilidad dela paja dela cebada con dietas de harina de maní altas y bajas. El incremento en la digestibilidad de la fibra cruda con la harina de maní en dosis altas se atribuyó al calcio suplementado. La adaptación de los ovinos a las dietas fue notada conforme progresaba el experimento junto con una amplia variación entre los animales en ingestión y digestibilidad de algunos constituyentes de la dieta. La retención de nitrógeno fue mas alta en aquellos animales alimentados con niveles altos de harina de maní, y debido a una mas peque?a excreción de urea.

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Résumé Des essais de digestibilité et de bilan ont été effectués sur six moutons pour étudier l’influence d’un complément de calcium sur la consommation et la digestibilité de paille d’orge avec une proportion faible ou élevée de tourteau d’arachide. Une augmentation de la digestibilité de la cellulose brute de ce dernier a été attribuée à l’addition de calcium. L’adaptation des moutons aux rations a été progressive mais une grande variation de la consommation et de la digestibilité de quelques constituants alimentaires a été constatée entre les animaux. La rétention d’azote était plus élevée chez les animaux ayant re?u une proportion élevée de tourteau d’arachide, par suite d’une excrétion plus faible d’urée.

     

Jojoba seed meal proteins associated with proteolytic and protease inhibitory activities

The jojoba, Simmondsia chinensis, is a characteristic desert plant native to the Sonoran desert. The jojoba meal after oil extraction is rich in protein. The major jojoba proteins were albumins (79%) and globulins (21%), which have similar amino acid compositions and also showed a labile thrombin-inhibitory activity. SDS-PAGE showed two major proteins at 50 kDa and 25 kDa both in the albumins and in the globulins. The 25 kDa protein has trypsin- and chymotrypsin-inhibitory activities. In vitro digestibility of the globulins and albumins resembled that of casein and soybean protein concentrates and was increased after heat treatment. The increased digestibility achieved by boiling may be attributed to inactivation of the protease inhibitors and denaturation of proteins.     

Development of the Regional Policy Process for Air Pollution in South Asia,Southern Africa and Latin America

Projections indicate that large increases in emissions may occur in developing countries during the next twenty to fifty years if current development patterns persist. This paper describes the development of co-operation regarding air pollution issues in three sub-regions of three continents. Experiences gained through activities within a programme on Regional Air Pollution in Developing Countries are used to illustrate progress. The sub-regional process in South Asia developed through a series of meetings that led to the Malé Declaration. In southern Africa a policy dialogue led to the Harare Resolution targeted towards progress in the SADC region. A policy dialogue in Buenos Aires concentrated on issues related to regional harmonisation of legal frameworks in the Mercosur region. In all regions the link between scientific information required to support decision making has been emphasised. The sub-regional policy processes are analysed in relation to availability of required scientific information and compared to the process that led to protocol development in Europe.     

Ammonium oxidation coupled to dissimilatory reduction of iron under anaerobic conditions in wetland soils

In exploring the dynamics of iron and nitrogen cycling in sediments from riparian forests we have observed a redox reaction that has not been previously described. During incubations of soil slurries under strictly anaerobic conditions, we repeatedly measured an unexpected production of both nitrite () and ferrous iron [Fe(II)]. Using this indirect evidence we hypothesize that, under anaerobic conditions, there is a biological process that uses ferric iron [Fe(III)] as an electron acceptor while oxidizing ammonium () to for energy production. This oxidation under iron reducing anaerobic conditions is thermodynamically feasible and is potentially a critical component of the N cycle in saturated sediments.     

Leaching of nitrate in calcareous soils as influenced by its adsorption on calcium carbonate

Adsorption of the nitrate ion on calcium carbonate and its leaching in calcareous soils were examined by equilibrium and elution techniques. Nitrate ions adsorbed on the surface of CaCO₃ fitted the Langmuir model well at an equilibrium concentration of 40 ppm NO₃⁻. Sulphate ions reduced adsorption of nitrate. Data for elution of surface-applied nitrate from laboratory soil columns, when plotted in the form of elution curves and semi-log plots, indicated interactions of nitrate with the soils. The elution curves had long trailing portions due to desorption of nitrate. The length of the trailing portion of a curve was determined by the amount of nitrate adsorbed which in turn seems to depend upon the total surface area of CaCO₃. Sulphate ions when present in the displacing fluid seem to desorb nitrate ions from the surface of the CaCO₃, whereas chloride ions have little or no effect.     

Occurrence of Fusarium species and mycotoxins in nepalese maize and wheat and the effect of traditional processing methods on mycotoxin levels

Maize (Zea mays) and wheat (Triticum aestivum) collected in the foothills of the Nepal Himalaya Mountains were analyzed for Fusarium species and mycotoxins: fumonisins, nivalenol (NIV), and deoxynivalenol (DON). Predominant species were Gibberella fujikuroi mating population A (F. moniliforme) in maize and F. graminearum in maize and wheat; G. fujikuroi mating population D (F. proliferatum), F. acuminatum, F. avenaceum, F. chlamydosporum, F. equiseti, F. oxysporum, F. semitectum, and F. torulosum were also present. Strains of G. fujikuroi mating population A produced fumonisins, and strains of F. graminearum produced NIV or DON. By immunoassay or high-performance liquid chromatography, fumonisins were >1000 ng/g in 22% of 74 maize samples. By immunoassay or fluorometry, NIV and DON were >1000 ng/g in 16% of maize samples but were not detected in wheat. Fumonisins and DON were not eliminated by traditional fermentation for producing maize beer, but Nepalese rural and urban women were able to detoxify contaminated maize by hand-sorting visibly diseased kernels.     

The role of potassium in sustaining yields in a long-term rice-wheat experiment in the Indo-Gangetic Plains of Nepal

A long-term soil fertility experiment (1988-1999) at the Regional Agricultural Research Station, Bhairhawa, Nepal, was analysed to determine: (1) how long the yields of rice (Oryza sativa L.) and wheat (Triticum aestivum L.) can be sustained without K but with N and N+P (NP) applied with or without farmyard manure (FYM) and green manure, and (2) the impact of K application on yields. Starting from the 1995 wheat season, the experiment was modified to accommodate K at 0, 42, and 84 kg ha^-1 in plots receiving NP to study the response of rice and wheat to K. Both rice and wheat responded to K application but the response of wheat was substantially higher, indicating that the availability of native K may have been lower in wheat. Rice yields were lower in treatments without P than with P, and yields declined significantly (0.11-0.20 Mg ha^-1 year^-1) in all the treatments except in NP and NP+FYM. Wheat yield was more adversely affected than rice yield when P and K were not applied. In addition, wheat yields were low (average 0.5-2.1 Mg ha^-1 in various treatments). Wheat yields declined (0.08-0.12 Mg ha^-1 year^-1) in all but FYM treatments indicating the role of FYM in sustaining yields. The interaction of K deficiency with Helminthosporium leaf blight (spot blotch and tan spot) is also suggested as one of the factors limiting wheat yields. The estimated K balance in soil was highly negative. Results suggest that farmers should apply adequate amount of K for higher and sustainable rice and wheat yields.     

Effect of transpiration on iron uptake and translocation in lowland rice

We evaluated six lowland rice (Oryza sativa L.) genotypes with contrasting responses to increasing Fe²⁺ concentrations under conditions of both low (0.3 kPa) and high (2.4 kPa) vapor pressure deficit. Dry atmospheric conditions generally enhanced transpiration with concomitant increases in Fe uptake and leaf bronzing. Some resistant genotypes were able to limit the water loss by transpiration under higher Fe concentrations thus attenuating negative effects associated with increased Fe²⁺ translocation at high vapor pressure deficit.     

Imidazolinone-tolerant crops: history, current status and future

Imidazolinone herbicides, which include imazapyr, imazapic, imazethapyr, imazamox, imazamethabenz and imazaquin, control weeds by inhibiting the enzyme acetohydroxyacid synthase (AHAS), also called acetolactate synthase (ALS). AHAS is a critical enzyme for the biosynthesis of branched-chain amino acids in plants. Several variant AHAS genes conferring imidazolinone tolerance were discovered in plants through mutagenesis and selection, and were used to create imidazolinone-tolerant maize (Zea mays L), wheat (Triticum aestivum L), rice (Oryza sativa L), oilseed rape (Brassica napus L) and sunflower (Helianthus annuus L). These crops were developed using conventional breeding methods and commercialized as Clearfield* crops from 1992 to the present. Imidazolinone herbicides control a broad spectrum of grass and broadleaf weeds in imidazolinone-tolerant crops, including weeds that are closely related to the crop itself and some key parasitic weeds. Imidazolinone-tolerant crops may also prevent rotational crop injury and injury caused by interaction between AHAS-inhibiting herbicides and insecticides. A single target-site mutation in the AHAS gene may confer tolerance to AHAS-inhibiting herbicides, so that it is technically possible to develop the imidazolinone-tolerance trait in many crops. Activities are currently directed toward the continued improvement of imidazolinone tolerance and development of new Clearfield* crops. Management of herbicide-resistant weeds and gene flow from crops to weeds are issues that must be considered with the development of any herbicide-resistant crop. Thus extensive stewardship programs have been developed to address these issues for Clearfield* crops.     

Some aspects of reproductive performance in selected town-supply dairy herds

Breeding and production data were collected from 20 town-supply dairy herds in the Manawatu/Horowhenua region. Calving interval, calving to first service interval, first service to conception interval, inter-service interval, calving rate to first service and services per cow calving were 384, 85, 11, 43 days, 51% and 1.7, respectively, for the pooled population of 12, 056 calvings. The mean milk yield was 3730 litres per cow and the mean lactation length 291 days. Age, herd, season within year, and year, had statistically significant effects on reproductive performance, although the amount of variation due to these variables was small. The younger cows (2-year-olds) were relatively poor performers. Reproductive performance was best during the spring. Days from calving to first service, and from first service to conception, were of similar importance in determining differences in calving interval. A high incidence (25%)of return intervals of more than 49 days was found between first and second service. It was concluded from the data that a programme for breeding each cow as she comes into oestrus 46–66 days post-partum is a simple and appropriate procedure for achieving a 365-day calving interval. Such a programme is more likely to be successful if continued attention is paid to both heat-detection procedures and the nutritional requirements of animals during rearing, late pregnancy and early lactation, and if routine pregnancy testing 6 to 8 weeks after service is used to recognise the problems of post-service anoestrus.