Grass is a complex crop and its value for agriculture must be assessed in terms of the quantity and quality of downstream livestock products (milk, meat and wool). In addition to being a natural low-cost feed for ruminants, grassland protects soil and water resources and enhances the landscape. Temperate grasslands support a major share of the world's milk and beef production but now there is increasing emphasis on sustainability in livestock farming systems rather than maximizing outputs. The economic sustainability of livestock producers in many developed temperate regions is increasingly linked to production from fewer animals giving a higher quality product. A key element in the efficiency of all grassland systems is to optimize the protein/energy balance of forage and value it in a similar way to other livestock feeds. Grasses are rich in energy comprising structural and non-structural carbohydrates while forage legumes are rich in protein. The main forage legumes used in Europe are white and red clover, and lucerne, which form an essential part of sustainable farming systems because of their high nutritive value and ability to fix nitrogen. The productivity of grasslands containing legumes generally reflects the amount of N fixation, which is 65–280 kg/ha/year in W. Europe. Animal production from white clover-based pastures in Europe can be 0·8 that obtained from grass pastures fertilized with 400 kg N/ha/year, and that from lucerne and red clover can be equivalent to animal production from such pastures.

The analysis of series of crop variety trials has a long history with the earliest approaches being based on ANOVA methods. Kempton (1984) discussed the inadequacies of this approach, summarized the alternatives available at that time and noted that all of these approaches could be classified as multiplicative models. Recently, mixed model approaches have become popular for the analysis of series of variety trials. There are numerous reasons for their use, including the ease with which incomplete data (not all varieties in all trials) can be handled and the ability to appropriately model within-trial error variation. Currently, the most common mixed model approaches for series of variety trials are mixed model versions of the methods summarized by Kempton (1984). In the present paper a general formulation that encompasses all of these methods is described, then individual methods are considered in detail.

Ticks are considered in Europe to be the most important arthropod group responsible for vector-borne diseases in humans, while in the tropics mosquitoes take over this position with ticks being the second most important. Over the last decade, vector-borne diseases have proliferated within Southern Europe (Blue tongue and West Nile viruses, both mosquito-borne diseases) while human ehrlichiosis (a tick-borne disease) has increased dramatically in Eastern Europe.

The nutritional and immunological importance of colostrum for the survival and development of the neonatal pig are reviewed. The pig is born with low body energy stores and devoid of serum immunoglobulins. Colostrum provides the piglet with both energy and maternal antibodies but its fat and protein composition is very variable. Colostrum is very digestible, and both colostral energy and nitrogen (N) are retained with a very high efficiency. Colostrum production by the sow assessed from the weight gain of the litter from birth to 24 h of age is very variable (from 1900 to 5300 g). There is no clear effect of litter size or parity, suggesting that colostrum production is a characteristic of the sow. Within a litter, colostrum consumption by the individual piglets varies considerably. It is independent of birth order, but related positively to birth weight and negatively to litter size. Other factors influencing colostrum consumption, including cold stress, premature birth and birth hypoxia, are discussed. Because of the epitheliochorial nature of the porcine placenta, the new-born piglet must acquire maternal immunoglobulin G (IgG) from ingested colostrum for passive immune protection until the immune system of the piglet becomes fully developed. Colostrum IgG concentrations in milk vary widely between individual sows both in initial concentration and in the rate at which concentrations decline during the first 24 h of life. The piglet can only absorb intact IgG prior to gut closure, which occurs in the first 24 h of life and is induced by intakes of colostrum which are insufficient to maintain piglet live-weight. As a result, the amounts of intact IgG absorbed by the piglet vary widely. The effects of colostrum consumption on neonatal survival are discussed. Consumption of colostrum in amounts sufficient to meet the energy requirement of the piglet is a major determinant for survival. Since most neonatal losses occur in the first 2 days of life, before acquisition of a maternal IgG for immune protection becomes important for survival, piglet serum IgG concentration does not correlate well with early survival but is important in later resistance to disease challenge. It is concluded that colostrum production is a good marker for the maternal quality of the sow. Future research should focus on the ability of the sow to produce more colostrum and on the possible delayed effects of passive immunisation on the health and performance of piglet at weaning and later in life.

For the determination of soil organic carbon (OC) concentrations, the availability of a fast, low-cost analysis method is required. The aim of the present study was to evaluate the possibilities of near infrared reflectance spectroscopy (NIRS) to build a spectral database and to develop calibrations for the prediction of organic carbon concentrations in grassland soils. NIRS spectra of 1626 soil samples from different grasslands (both agricultural and natural) were collected between 1100 and 2500 nm. NIRS calibrations were developed with modified partial least square regression and tested with independent validation samples. The best equations were obtained with the first derivative of the spectra without scatter corrections. For the global calibration, containing the samples of all origins, the standard errors of calibration (SEC) and of prediction (SEP) were respectively 3·70 g OC/kg dry soil (R2=0·89) and 3·95 g OC/kg dry soil (R2=0·88). The ratio of the standard deviation of the reference validation data to the SEP (RPD), indicating the performance of the calibration, was 2·9. Dividing the samples into groups according to their practice (agricultural or natural grassland), improved SEP by 5·8 and 7·7%, respectively. Dividing the samples into texture groups (clay, silt, sand) improved SEP for agricultural grassland by, on average, 7·4% and for natural grassland by 16·2%.

The present study was conducted to investigate whether white clover (Trifolium repens L.) in grazed swards in Uruguay can produce and shed sufficient seed, and whether sufficient seedlings can develop and survive, to make an important contribution to the long-term persistence of the species. Five sites, on which survival of white clover had been better than is usual in Uruguay, were studied in 1995–97. The sites had been sown with white clover 11–15 years previously and were managed mainly by cattle grazing. The number of white clover inflorescences/m2 was at least 18 at nearly half the counts in the study and the number of viable seeds in the top 5 cm of soil was at least 1500 at half the counts. The results for both the above variables suggest that all five sites had a supply of seed greater than a commercial seed rate at some times of the year. However, the number of seedlings/m2 was >100, a possible target in these conditions, at only one fifth of the counts, and the proportion of seedlings that survived from one recording date to the next (a period of 4–5 weeks) varied from >0·7 to zero. It seems, therefore, that, in these conditions, the failure of seeds to convert to established plants is likely to be a greater constraint than the production and shedding of seeds. There was considerable variability with time, and between and within sites at each stage of the reproductive cycle. On one site, competition from Bermudagrass (Cynodon dactylon) greatly reduced the number of white clover seedlings/m2. Overall, the results suggest that white clover in grazed swards in Uruguay can produce and shed sufficient seed, and that sufficient seedlings can develop and survive, to make a significant contribution to the long-term persistence of the species. However, each year there is a risk of seedlings being killed in dry, hot weather.

Three successive field experiments (2000/01–2002/03) assessed the effect of wheat cultivar (Consort, Hereward and Shamrock) and fungicide (epoxiconazole and azoxystrobin) applied at and after flag leaf emergence on the nitrogen in the above-ground crop (Total N) and grain (Grain N), net nitrogen remobilization from non-grain tissues (Remobilized N), grain dry matter (Grain DM), and nitrogen utilization efficiency (NUtEg=Grain DM/Total N). Ordinary logistic curves were fitted to the accumulation of Grain N, Grain DM and Remobilized N against thermal time after anthesis and used to simultaneously derive fits for Total N and NUtEg.

When disease was controlled, Consort achieved the greatest Grain DM, Total N, Grain N and NUtEg; in each case due mostly to longer durations, rather than quicker rates, of accumulation. Fungicide application increased final Grain DM, Grain N, Total N and Remobilized N, also mostly through effects on duration rather than rate of accumulation. Completely senesced leaf laminas retained less nitrogen when fungicide had been applied compared with leaf laminas previously infected severely with brown rust (Puccinia recondita) and Septoria tritici, or with just S. tritici. Late movement of nitrogen out of fungicide-treated laminas contributed to extended duration of both nitrogen remobilization and grain N filling, and meant that increases in NUtEg could occur without simultaneous reductions in grain N concentration.

Three animal experiments were carried out to investigate the effect of condensed tannins (CT) on parasitic gastrointestinal (GI) nematode infections of sheep. Experiment 1 investigated the long-term effect of varying dietary levels (0–80 g/kg diet) of quebracho tannin (QT) on faecal egg counts (FEC) and feed consumption of lambs with experimental Haemonchus contortus infection. Dietary QT did not cause significant reductions in FEC although at high inclusions of QT there was an indication of a reduction in FEC. Some undesirable effects of tannins were also observed; feed consumption was significantly reduced (P<0·001) by dietary QT, while faecal water content increased significantly (P<0·01). In order to reduce the undesirable effects of dietary tannins in the host, short-term exposure to tannins was adopted. QT was administered as a drench, for 3 consecutive days, to growing lambs infected with H. contortus (Experiment 2) or its mixed infection with Trichostrongylus colubriformis (Experiment 3) and its effect on FEC, worm burdens and the GI tract was investigated. Administration of QT drench to sheep infected with the abomasal H. contortus alone significantly (P<0·05) reduced FEC and worm burdens (P<0·01) compared with the control group. In Experiment 3 the drench had little effect (P>0·05) on small intestinal T. colubriformis although similar effects to those seen in Experiment 2 on H. contortus were observed, suggesting that the location of the nematodes in the gut might be important. Apart from reducing feed consumption, the drench caused some physiological changes in the gut, particularly an increase in faecal water and mucus content, which were more marked following the drench than seen in the dietary inclusion trial. In conclusion, unlike dietary inclusion, QT worked more quickly and more effectively against H. contortus when administered as drench; T. colubriformis may require a higher dose or a prolonged exposure to the drench. The present findings suggest that it may be possible, perhaps with limited use of synthetic anthelmintics, to design appropriate feeding strategies using tannins to alleviate the problem of nematode infections in small ruminants. This may be particularly relevant to the tropics and subtropics where many species of plants contain high levels of tannins and where extracts high in tannins are readily available.

Bacterial growth inhibiting effects of dipicolinic acid (DPA), which occurs in spores of probiotic Bacillus spp. strains, was studied with a range of Lactobacillus spp. (13), Enterococcus spp. (14), and E. coli strains (8) in vitro. In vivo effects were studied in a broiler chicken nutrition trial and DPA supplemented feed (10 g/kg).

In vitro studies showed that DPA inhibited growth of most Lactobacillus spp. strains to a larger extent than E. coli strains. Enterococci were generally influenced less by DPA. However, in each group of bacteria some strains were less inhibited by DPA than others. Intestinal lactic acid bacteria in the jejunum and ileum showed a trend (P[les ]0·1) for lower counts in birds fed the DPA-supplemented feed on day 14 and 21. Counts of enterobacteria were not significantly influenced by DPA. No differences in colony counts were observed in 28-day-old animals. Digesta pH was not statistically reduced, but a lower crop pH was recorded throughout the nutrition trial.

The study showed that dipicolinic acid, present in probiotic Bacillus spp. spores, is inhibitory for in vitro growth of most lactobacilli and enterobacteria, while growth of enterococci was less inhibited. Intestinal colony counts in young broiler chickens fed a DPA-supplemented diet in part mirrored in vitro results.