Onion (Allium cepa L.) and bean (Phaseolus vulgaris L.) seedlings grown in soil treated with DCPA (dimethyl tetrachloroterephthalate) were less susceptible to northern root-knot nematode (Meloidogyne hapla Chitwood) infection than seedlings grown in untreated soil. DCPA treatment of nematode larvae did not alter their pathogenicity. Resistance could be correlated with altered cell structure of the root epidermis, increased root exudate as evidenced by soil adherence, reduced fibrous root development, or both.

We examined and described colonization of MRSA in the anterior nares and throat from 184 community-recruited injection drug users. Thirty-seven (20%) were positive for MRSA: most (34, 92%) were carriers in the nares; while only three (8%) were carriers detected by throat swabs alone. The majority (29, 78%) of MRSA isolates were PVL positive.

This triennium began with an action to re-create the Terms of Reference for the Working Group Global VLBI (WG-GV). These had been lost over the years since the Group was established in 1990. Fortunately, the personal archive of one long-term member yielded a copy of the original memorandum by R. D. Ekers, which was found to coincide quite well with current practice and areas of interest. New Terms of Reference, based on modern conditions, were drafted and accepted by both IAU and URSI.

In the Central Kenyan Highlands, dairy cattle ownership is a crucial element in poverty alleviation. For example, in Kiambu district just north of Nairobi, out of the population of 744010, 48% of 189709 households stall feed dairy cattle. Farm sizes average 1.1 to 2.0 ha per household. Producing sufficient forage for dairy cattle is difficult and low dry matter intake constrains dairy production and there is a positive correlation between stover intake and milk yield.. Napier grass comprised 40% of the total dry matter fed to cattle and maize forage 24% according to the project’s Rapid Rural Appraisal, maize thinnings and stover being routinely fed to livestock. In another survey, dry maize stover accounted for nearly 65% of dry matter intake of dairy cattle during October.

In sub-Saharan Africa mixed crop-livestock systems predominate in the semi-arid, sub-humid and cool highland zones. In these areas, systems intensify and crops and livestock become increasingly integrated as the human population increases and land becomes a more important constraint than labour (Boserup, 1965; McIntire et al., 1992). As intensification progresses, use of crop residues moves from open access to crop fields, following harvest, to labour intensive management of cereals as dual-purpose crops.

Considering the escalating population growth, shrinking grazing land and increased demand for animal products, sustainable livestock production through improved management is critical to the issue of food security and poverty alleviation in most developing countries. The challenge facing the research and extension services in these countries is to increase productivity in the livestock sector while sustaining and enhancing the productive potential of the available natural resources.

VLBA observations of the two-sided emission structures in 3C 84 have been used to study the ionized gas in the vicinity of the presumed accretion disk on parsec scales. Strong free-free absorption is seen with a radial gradient, but only upper limits have been obtained on a stimulated recombination line at 23 GHz.

Twelve dairy cows in early lactation were offered low (L; 215 g/kg) or high (H; 449 g/kg) dry matter(DM) content silages, prepared using material from the same sward. In addition, all animals received 9 kg/day, of supplements based on barley (B), sugar-beet pulp (SB) or a 50: 50 mixture of the two (B: SB), in two equal portions at 07:30 and 14:30 h. The six treatments were offered in an incomplete Latin square design. Mean intakes of H (14·4 kg DM per day) were significantly higher than intakes observed for L (10·0 kg DM per day) (P < 0·001). Within silage type, highest intakes were observed for cows receiving the SB supplement (P < 0·01). Higher intakes of H were reflected in higher total milk yield (P < 0·05) as well as fat (P < 0·05) and protein (P < 0·01) yield. Milk protein concentration was greater for animals receiving silage H (P < 0·001), with lower values being observed for animals consuming SB (P < 0·05), within silage type. Time spent eating, duration and number of meals were similar for either silage and the higher intakes of H silage reflected greater intake rates (g DM per min) (P < 0·001) resulting in larger meal sizes (P < 0·001). All chewing indices (time spent eating silage, ruminating and total time chewing per kg DM ingested) were greater for the L silage (P < 0·001). It is concluded that the benefits in forage intake with higher DM grass silages, for high yielding dairy cows, are associated with consequential benefits in milk yield and milk protein content. The most likely explanation for the greater intakes is a faster particle breakdown in the rumen allowing larger meal sizes before animals became constrained. The higher intakes of silage when animals consumed the SB supplement may be due to a slower rate of fermentation of the supplement, which was more closely matched to that of silage. Although not significant there was a tendency for differences in silage intake between animals receiving B compared with SB supplements to be greater for animals receiving the H silage suggesting that supplementation strategies to ensure optimal forage utilization may differ for silages of differing DM content.

Sanda et al. (1999) studied the effects on crossbred steer liveweight gain of alternating the same quantities of napier grass and barley straw at five day intervals over a 40 day period. These animals lost significantly more weight (p<0.05) than animals on one and ten day frequencies of alternation and those receiving the same quantities of the two feeds mixed together at each meal. These responses could not be explained by differences in in vivo digestibility or intake. The present study was designed to test the hypothesis that there are gradual changes in the rumen environment as animals adapt to the intake of a given forage and that, during this adaptive phase nitrogen is not used efficiently, which could explain the poor performance.

Previous studies have shown that the timing of supplement distribution and supplement type can have implications on forage intake and/or production. For example, Robinson et al. (1997) showed that feeding a protein supplement at 00.30 h compared with 08.30 h increased fat yield through stimulation of rumen fermentation. The objective of the present trial was to test the hypothesis “that supplying a protein supplement either before or after silage was offered would affect feeding pattern and silage intake”.

Twelve multiparous cows, with average starting milk yield of 25.4 (s.d. 5.95) kg/day were allocated to one of six treatments in an incomplete Latin square with four periods of 21 days. Grass silage (219 g/kg DM, 151 g CP/kg DM) was fed ad libitum mixed with barley in the ratio 3:1 on a DM basis.

Parameters from in vitro gas production and in situ degradability are often used to predict digestibility and intake in vivo. However, these methods use dried ground feed samples and cannot be expected to estimate the effect of changes in physical form or particle size. Previous work (Romney and Gill 1998) has indicated that short term intake rate (STIR) values showed potential to rank a variety of feeds in terms of their ad libitum dry matter intake, rate of passage and digestibility. Since STIR values are determined on feeds “as offered” it is likely they will reflect the effects of physical structure on in vivo parameters. The present work examines whether measurement of STIR values can be used to predict in vivo responses to changes in particle size distribution in chopped forages.

Seasonal variation in feed supply, is recognised as an important constraint to animal production in the tropics. However, day to day fluctuations in quantity and quality of feed are also common in stall-fed animals on smallholder dairy farms. Opportunistic use of feeds available in small amounts, such as residues from food crops, weeds and purchased fodder is common. In addition, amounts of cut green fodder may be reduced or absent on some days. Ruminant animals require time to adapt to a given feed and it might be expected that frequent and abrupt changes of this type might have a negative effect on feed utilisation and animal performance. The objective of the experiment was to determine whether the way in which two fodders, with significantly different DM, CP and fibre contents, were offered, would influence digestibility and liveweight gain in cross-bred cattle.

In the tropics, fodder trees and shrubs are a very important source of nutrients, especially nitrogen. In vitro gas production methods used for food evaluation were originally developed for investigation of temperate forages and used a nitrogen-rich medium. Evaluation of fodder tree leaves in this medium may mask the effect of their nitrogen which it is important to understand. This trial studied the fermentation of a range of tropical fodder trees and shrubs in both nitrogen-rich and nitrogen-free media, in order to identify the main chemical entities contributing to gas production and the time within which such contributions were most important.

Multi-frequency VLBA observations were used to study the magnitude and radial dependence of free-free absorption of the radio emission from the counterjet in 3C 84.

Parameters from in vitro gas production techniques could have potential as predictors of dry-matter intake (DMI) and digestibility. Fermentation is usually carried out under conditions where nitrogen (N) is not limiting. Therefore where N supply is a constraint to intake and digestibility, prediction equations may be inaccurate. This study compared the use of N-free and N-rich media in an in vitro fermentation method (Theodorou et al., 1994) and studied the relationships between in vitro and in vivo parameters obtained using both media.

It might be expected that the same physical characteristics of a feed, determining the rate of breakdown in the rumen and physical fill, might also influence the rate at which an animal is able to eat a feed. Moseley and Manendez (1989) observed a positive relationship between intake rate measured over 1 minute periods and voluntary intake ad libitum. These authors also suggested that determination of eating rate could be used as a rapid method to evaluate intake characteristics of forages. The present work examines further the potential of what will now be referred to as short term intake rate (STIR value), as a method to rank forages in terms of their potential intake, digestibility and rate of passage.

We describe a space VLBI experiment involving an earth-orbiting satellite (SURFSAT) and simulated satellites, a space VLBI ground tracking station, an array of ground radio telescopes, and a space VLBI correlator. The purpose of this experiment was to provide as complete as possible an end-to-end simulation of space VLBI in preparation for the first space VLBI mission, VSOP, and in particular to test the most critical aspect of space VLBI, viz. the ability to generate a stable and accurate frequency standard (clock) for the orbiting VLBI element.

The effects of experimental Trypanosoma congolense infection on the digestive physiology and nutrient utilization in Gobra zebu and N'Dama cattle were examined in a 16-week trial. A pair-feeding procedure permitted examination of the effects of both food intake and trypanosomosis infection. Twenty Gobra and 16 N'dama bulls aged between 1 and 2 years were paired on a live-weight basis within each breed. One of each pair was chosen at random to serve as an uninfected control while the other was inoculated intradermally with 104 T. congolense in mice blood in the 6th week of the experiment. Packed cell volume and parasitaemia data were collected weekly throughout the trial. Total dry-matter intake (TDMI) and live-weight changes were measured weekly in all animals during the 16-week trial. Rate of passage (RoP) and dry matter digestibility were evaluated before and after infection.

While infection significantly depressed TDMI in both breeds (P < 0·05), neither infection nor breed affected the RoP and the apparent digestibility of the dry matter. Significant changes in live weight attributable solely to the infection were observed in both breeds. Loss of body weight was more severe (P < 0·05) in infected Gobra bulls compared with N'dama bulls possibly implying a superior efficiency of nutrient utilization by the N'dama during infection. In the course of the trial, one N'dama and three Gobra bulls that presented severe clinical symptoms of trypanosomosis were treated and withdrawn from the experiment along with their pair-fed controls.

In conclusion, the RoP and the digestive efficiency were not affected by infection and breed differences. Also, the trypanotolerance mechanism does not seem to be affected by anorexia but rather by the ability to conserve body reserves during infection.