The effects of straw incorporation (early and late cultivation) and straw burning were contrasted in a split-plot study examining the impact of long-term straw residue management, and six fertilizer nitrogen (N) rates on soil mineral nitrogen, crop fertilizer N requirements and nitrate leaching losses. The experiments ran from 1984 to 1997 on light-textured soils at ADAS Gleadthorpe (Nottinghamshire, UK) and Morley Research Centre (Norfolk, UK).

Soil incorporation of the straw residues returned an estimated 633 kg N/ha at Gleadthorpe and 429 kg N/ha at Morley on the treatment receiving 150 kg/ha per year fertilizer N since 1984. Straw disposal method had no consistent effect on grain and straw yields, crop N uptake, or optimal fertilizer N rates. In every year there was a positive response (P<0·001) to fertilizer N in straw/grain yields, N contents and crop N offtakes at both sites. Nitrate leaching losses were slightly reduced by less than 10 kg N/ha where straw residues had been incorporated, while fertilizer N additions increased nitrate leached at both sites.

At both sites there was a consistent effect (P<0·001) of straw disposal method on autumn soil mineral N, with values following the pattern burn>early incorporate>late plough. The incorporation of straw residues induced temporary N immobilization compared with the treatment where straw was burnt, while the earlier timing of tillage on the incorporate treatment resulted in slightly more mineral N compared with the later ploughed treatment. Fertilizer N rate increased (P<0·001) soil mineral nitrogen at both sites. At Morley, there was more organic carbon in the plough layer where straw had been incorporated (mean 1·09 g/100 g) rather than burnt (mean 0·89 g/100 g), and a strong positive relationship between organic carbon and fertilizer N rate (r2=93·2%, P<0·01). There was a detectable effect of fertilizer N on readily mineralizable N in the plough layer at both Gleadthorpe (P<0·001) and Morley (P<0·05). At Morley, there was a consistent trend (P=0·06) for readily mineralizable N to be higher where straw had been incorporated rather than burnt, indicating that ploughing-in residues may contribute to soil nitrogen supply over the longer term.

The effects of supplying the fertilizer nitrogen (N) as a recommended quantity of ammonium nitrate or as a commonly used dose of poultry manure on yield of sugarbeet infected with Beet mild yellowing virus (BMYV) or Beet yellows virus (BYV) were studied in field experiments at IACR-Broom's Barn in 1990, 1991 and 1992. Three N fertilizer treatments comprising Zero (N0), standard rate of 110 kg N/ha (N1) and poultry manure equivalent to c. 300 kg/ha of available N (N2) were applied to plots which were uninoculated or were subsequently inoculated with either BMYV or BYV. Averaged over virus treatments, N1 increased sugar yields by 23% relative to N0: there was no further increase when N2 was applied. When averaged over N treatments, early virus yellows infection reduced the sugar yields by 23%. Generally there was no significant interaction between N supply and virus infection. There was no evidence that the large N supply could reduce the yield effect of virus yellows infection, as had previously been thought. Crops infected from late July produced similar yields to uninoculated controls. The main effect of virus yellows was to reduce the efficiency of radiation conversion even when account was taken of the light intercepted by yellow foliage. Whilst the N2 treatment helped to maintain a green leaf cover throughout the season on virus yellows infected crops, it had no effect on virus replication. Beet processing quality was impaired by increasing the N supply and by virus infection, but again there were generally no significant interactions between infection and N rate.

In vivo digestibility trials were carried out using six young rams fed with Atriplex halimus biomass harvested in summer (A) and in early autumn (B), and with a mixture of mid-autumn Atriplex halimus and wheat straw (5[ratio ]1 ratio on fresh matter basis) (C). Atriplex halimus had a high protein content (139·0, 135·9 and 193·4 g/kg DM in A, B and C respectively), but was rich in sodium chloride, especially in summer (145·9 g/kg DM), limiting its use as feed. The summer forage had a higher organic matter (OM) digestibility coefficient than the autumn forage (0·663 v. 0·530) but lower digestible OM intake (16·8 v. 29·4 g/day per kg BW0·75). In autumn forage, the combination with straw did not influence the digestibility of organic matter, whereas it enhanced DOM intake in comparison with the Atriplex halimus on its own (35·7 v. 29·4 g/day per kg BW0·75).

This work evaluated the effect of seed size and morphology on the development and biomass of durum wheat seedlings. Three different seed-grading sizes selected by sieving were used in glasshouse experiments, and a set of three developmental and 23 biomass-related indices were measured on eight genotypes, at two moisture levels. The influence of seed size on seedling development was studied at high and low temperatures (22/12 °C, and 15/5 °C day/night temperatures, respectively), in growth chambers.

The area of the seed and the area of the embryo were the seed morphological traits most affected by seed size. Seed size was strongly associated with seedling development and seedling biomass until the complete extension of the first two leaves, at the fourth leaf stage. The rate of first-leaf growth and the area of the first leaf were the developmental and biomass traits, respectively, most sensitive to seed-grading size.

The marginal winter pastures of reindeer and caribou (Rangifer tarandus) in Arctic and sub-Arctic areas are assumed to be nitrogen- and mineral-poor. Reindeer eat a mixed diet consisting of nitrogen-deficient lichens and a wide variety of vascular plants in winter. Some reindeer populations manage to maintain carcass mass outside the growing season and very little is known about the ability of reindeer to utilize vascular plants in this season. The chemical composition and in vitro digestibility of 17 species of vascular forage plants and one species of moss collected mid-winter from beneath the snow at an inland winter pasture in northern Norway were determined. Wintergreen parts of graminoids had a high content of crude protein (0.072–0.108 g/kg dry matter (DM)) and water-soluble carbohydrates (0.098–0.167 g/kg DM) and were highly digestible (50–65% IVDMD) compared with the withered parts of the plants (27–53% IVDMD). The digestibility of both shrubs and graminoids was inversely related to content of cellulose and lignin, but positively correlated with increasing contents of water-soluble carbohydrates. Shrubs were relatively calcium-rich (3.6–6.1 g/kg DM) while wintergreen graminoids contained up to 10.0 g/kg DM of potassium, 1.5 g/kg DM magnesium and 2.1 g/kg DM phosphorus. The present study demonstrates that the wintergreen parts of several species of vascular plants are nutritious, containing high levels of nitrogen and minerals, and that they are highly digestible to reindeer in winter. Vascular plants may, therefore, be more important to reindeer and caribou in winter than previously realized.

Ethiopia is the centre of origin and diversity of Vernonia galamensis, which is a new potential industrial oilseed crop. Seeds of Vernonia are rich in vernolic acid, a naturally epoxidized fatty acid with unique chemical (epoxy) and physical (low viscosity) properties. Vernolic acid is a useful raw material for manufacturing paints and coatings. No effort has been made so far in Ethiopia or elsewhere to improve this plant. Therefore, an experiment was conducted in three contrasting agroclimatic zones (Alemaya, Harar and Babile) using eight accessions to assess the genotypic (GCV) and phenotypic (PCV) coefficients of variation, to estimate broad sense heritability (h2B) and genetic advance (GA) as a per cent of the mean for 17 pheno-morphic and agronomic traits.

Considering GCV, h2B and GA (as per cent of the mean) simultaneously as the best estimators of the amount of advance expected from selection, secondary head number (28·90, 0·90 and 56·60), secondary branch number (13·90, 0·67 and 51·97), and seed number per head (15·97, 0·72 and 27·92) gave the highest values at Alemaya, Harar and Babile, respectively. This shows that a satisfactory selection program for improvement of these characters is possible in V. galamensis var. ethiopica at each specific location.

A study was carried out on five lowland farms in Northern Ireland over 3 years to investigate the effect of crossbred ewe and ram genotype on ewe prolificacy, lamb viability and weaned lamb output. Four crossbred ewe genotypes were sourced from six hill farms involved in a previous study – Bluefaced Leicester×Blackface (BLXB), Texel×Blackface (TXB), Suffolk×Cheviot (SXCH) and Texel×Cheviot (TXCH). On each farm, groups of 20–30 of each crossbred ewe genotype were mated with Suffolk or Texel rams. Throughout the 3 years of the study, the ewe genotypes lambed at 1, 2 and 3 years of age. Within each of the ram breeds, high lean growth index rams sourced from UK sire reference schemes were compared with rams sourced from flocks not involved in objective genetic improvement programmes (control). BLXB ewes were the most prolific of the four ewe genotypes producing 1.73 lambs per ewe lambed compared with 1.47 for TXB, 1.46 for SXCH and 1.41 for TXCH (P<0.001). Lamb mortality was similar for the four ewe genotypes, thus number of lambs weaned was greatest for the BLXB ewes (P<0.001) with the other three crosses producing similar numbers of lambs. A greater proportion (P<0.05) of SXCH ewes lambed without assistance compared with BLXB and TXB ewes and a greater proportion of TXCH ewes had abundant supplies of colostrum compared with the other crosses (P<0.10). Output of weaned lamb per ewe lambed and per ewe metabolic live weight (P<0.001) was greatest in the BLXB ewes. Ewe productivity, prolificacy, number of lambs weaned and the proportion of ewes lambing without assistance increased with ewe age (P<0.001). Lamb growth rate from birth to 6 weeks and from birth to weaning increased with ewe age (P<0.05). Crossbred ewes lambing at 3 years old had a greater output of weaned lamb compared with ewes lambing at 1 and 2 years old (P<0.001). Ram genotype had no effect on ewe prolificacy, lamb viability or pre-weaning growth rates, although Texel-sired lambs had lower birth weights than Suffolk-sired lambs and control-sired lambs had lower birth weights than high lean index-sired lambs (P<0.05).

A study was carried out on five lowland farms in Northern Ireland over 2 years to investigate the effects of crossbred ewe and ram genotype on lamb carcass characteristics. Four ewe genotypes were sourced from six hill farms – Bluefaced Leicester×Blackface (BLXB), Texel×Blackface (TXB), Suffolk×Cheviot (SXCH) and Texel×Cheviot (TXCH). On each farm groups of 20 to 30 of each crossbred ewe genotype were crossed with Suffolk or Texel sires. Within each of the ram breeds, high lean growth index rams sourced from UK sire reference schemes (SRS) were compared with rams sourced from flocks not involved in objective genetic improvement programmes (control). Throughout the 2 years of the study the ewes lambed at 1 and 2 years of age. Lambs from each of the crosses were slaughtered at 36, 44 and 52 kg live weight. Assessed on a 5-point scale, lambs from BLXB ewes had the poorest conformation classification values (2.8) (P<0.001) compared with 3.0–3.2 (S.E. 0.051) for lambs from the other ewe genotypes. Lambs from TXB, SXCH and TXCH ewes had similar conformation classification values. The differential in conformation classification values between lambs from BLXB ewes and those from the other genotypes was greater when the ewes were crossed with Texel (0.6 units) compared with Suffolk rams (0.3 units) (P<0.05). Differences in conformation between the sire breeds varied according to ewe genotype (P<0.05). When crossed with BLXB ewes there was no difference between Texel and Suffolk-sired lambs in terms of conformation classification values (2.7 v. 2.8 (S.E. 0.07), while with all the other ewe genotypes, Texel-sired lambs had a significantly higher conformation classification than Suffolk-sired lambs (3.5 v. 3.0 when crossed with T×B; 3.2 v. 2.9 when crossed with SXCH; 3.4 v. 3.0 when crossed with TXCH (S.E. 0.07)). Sire reference scheme-sired lambs had greater growth rates from birth to slaughter (203 g/day) compared with control-sired lambs (193 g/day) (S.E. 3.7 days) (P<0.05) and were of an improved conformation classification (3.1 v. 3.0 (S.E. 0.04)) (P<0.01). There was a significant interaction (P<0.01) between ram breed and ram source on lipid content of the carcass. Within the Suffolk-sired lambs, there was no significant difference between SRS-sired lambs (197 g/kg) and control-sired lambs (190 g/kg) (S.E. 6.2 g/kg). However, within the Texel-sired lambs, SRS-sired lambs had a lower lipid content (174 g/kg) than control-sired lambs (204 g/kg) (S.E. 6.2 g/kg) (P<0.01).

A study was carried out on five lowland farms in Northern Ireland over 2 years to investigate the effects of crossbred ewe and ram genotype on lamb meat quality. Four ewe genotypes were sourced from six hill farms – Bluefaced Leicester×Blackface (BLXB), Texel×Blackface (TXB), Suffolk×Cheviot (SXCH) and Texel×Cheviot (TXCH). On each farm groups of 20–30 of each crossbred ewe genotype were crossed with Suffolk or Texel sires. Within each of the ram breeds, high lean growth index rams sourced from UK sire reference schemes (SRS) were compared with rams sourced from flocks not involved in objective genetic improvement programmes (control). Throughout the 2 years of the study the ewes lambed at 1 and 2 years of age. Lambs from each of the crosses were slaughtered at 36, 44 and 52 kg live weight. Meat from lambs slaughtered at 36 kg had lower a* values (15.1) than meat from lambs slaughtered at 52 kg (17.0 S.E. 0.47) (P<0.05). Ewe genotype had no effect on any parameter of meat quality measured. The carcasses of lambs sired by Suffolk rams had a higher pHU than lambs sired by Texel rams (5.70 v. 5.65; S.E. 0.014; P<0.05) and hue angle was lower (P<0.05) in Suffolk-sired lambs (32.9°) compared with Texel-sired lambs (35.1°) (S.E. 0.62°). Warner–Bratzler shear force was lower in SRS-sired lambs (2.05 kg/cm2) compared with control-sired lambs (2.36 (S.E. 0.096) kg/cm2; P<0.05). Carcasses from male lambs had a greater cooking loss (217 g/kg) than from female lambs (196 S.E. 5.7 g/kg) (P<0.01) and meat from male lambs had greater values for Warner–Bratzler shear force (2.44 kg/cm2) than from female lambs (1.97 S.E. 0.098 kg/cm2) (P<0.001). Low, but statistically significant (P<0.05) correlations were obtained between carcass fat measurements and meat quality parameters (r = −0.29 for the relationship between cooking loss and fat depth over the gluteus medius P<0.001); r = 0.21 for the relationship between fat classification and C* values P<0.01). When meat quality parameters for each of the fat classes were averaged, significant linear regressions (P<0.05) were obtained between fat classification and pHU, a* and C* values.

The effects of feeding Leucaena leucocephala on semen quality and fertility were examined using four dihydroxy pyridone (DHP)-adapted (21.0, 26.5, 27.0 and 31.0 kg) and four DHP-unadapted (28.0, 31.0, 40.0 and 44.0 kg) South African indigenous Nguni bucks (mature male goats). The DHP-adapted bucks were assigned to air-dried Leucaena leucocephala forage (LL; Leucaena group) while the unadapted ones were maintained on a cereal-based concentrate diet (C; concentrate group) containing 122 g crude protein (CP)/kg over an 84-day period. Buck semen samples were collected on days 0 and 77 of the study. On the last day of the study (day 84), bucks in the Leucaena group were divided into two equal subgroups; a subgroup was assigned to Leucaena leucocephala-grass pasture (LGP) with ten does (mature female goats) while the second subgroup was assigned to natural pasture (NP) with nine does. Similarly, the two concentrate subgroups were separately assigned to mate nine and ten does on LGP and NP plots, respectively. The proportions of normal semen on both groups were not significantly different. However, semen quality on LL treatment increased significantly (P = 0.004) between days 0 and 77 and probably explains the significant (P<0.01) difference between the fertility rates of bucks on both treatments. There was no evidence that feeding LL was detrimental to semen quality and fertility of bucks and to conception among females mated by the bucks fed the forage; perhaps due to the fact that the bucks had adapted to DHP as a result of the DHP-degrading rumen bacteria (Synergistes jonesii) that were transferred to them by the does. Synergistes jonesii is known to be capable of detoxifying mimosine and its toxic metabolites to innocuous compounds.

Fresh cattle dung from four farms with different feeding strategies was used to create artificial dung pats in a continuously grazed pasture in order to compare the rejection of herbage growing around the pats, the effect on undisturbed herbage growth under cages and pat decomposition. The first farm was an extensive organic farm (ORGE) with young steers grazing on a biodiverse sward. The second was an intensive organic farm (ORGI) with dairy cattle grazing on a grass/clover sward during the day and fed low-protein forages indoors. The third dung used was from an integrated farm (INT), where the feeding strategy was aiming for high dung quality by including straw in the diet. The fourth examined dung was from a conventional farm (CONV) aiming for a high milk production per cow, where fertilized grazed grass was the main component of the diet. A human smell test was performed to rank the odour of the four dungs.

After 6 weeks of continuous grazing with dairy cattle, herbage yield around INT pats tended to be lowest, whilst undisturbed herbage yield in and around caged INT pats was highest (P<0·05). Therefore, it could be concluded that rejection was lowest for INT. The CONV pats gave highest rejection (P<0·05). However, herbage yield around the dung pats under grazing showed no significant correlation with both the human smell test and the contents of total-N and sugar in the rejected herbage.

The feeding strategy had a significant effect on the decomposition of dung pats under the cages. After 6 weeks, the most liquid and least fibrous dung (CONV) showed highest decomposition (P<0·05), whilst decomposition of the most solid and fibrous dung (ORGE) tended to be lowest. However, no relationship was found between the decomposition of dung and the rejection of herbage around the dung pats.

When combining a number of parameters determined in the experiment and comparing them using index figures for dung quality in terms of rejection, herbage growth and decomposition, the index figures of ORGI (102) and especially INT (113) were above average (100), while those of ORGE (94) and CONV (90) were below average. The difference between ORGI and INT might be explained by the addition of straw to the diet in the latter. The study showed that there are possibilities to improve dung quality by altering feeding strategy.

Progress in politics and science often happens by serendipity, and an unforeseen effect of the 2001 foot and mouth epidemic will be its impact on bovine tuberculosis in three areas. Cattle TB will be much worse, increasing the risk to public health, and ‘the highly emotive and complex issue’ of badgers and TB may be resolved after 30 years controversy. A critical reappraisal of these three areas is worthwhile.