Near-infrared reflectance spectroscopy was used to assess the mineral composition of both alfalfa (Medicago sativa L.) and white clover (Trifolium repens L.). Alfalfa (n=230) and white clover (n=97) plant samples from different locations in Uruguay representing a wide range of soil types were analysed. The samples were scanned for reflectance in a NIRSystems 6500 monochromator (NIRSystems, Silver Spring, MD, USA). Predictive equations were developed using modified partial least squares (MPLS) with cross validation to avoid overfitting. The coefficients of determination in calibration (R_{\rm cal}^{2}) and the standard errors in cross validation (SECV) were 0·93 (SECV: 1·6), 0·95 (SECV: 1·3), 0·93 (SECV: 1·9), 0·88 (SECV: 2·7), 0·82 (SECV: 0·3) and 0·75 (SECV: 4·7) for alfalfa and 0·98 (SECV: 0·8), 0·52 (SECV: 0·8), 0·97 (SECV: 2·7), 0·83 (SECV: 3·1), 0·82 (SECV: 1·9) and 0·45 (SECV: 2·6) for white clover, for N, Ca, K, P, Mg and S in g/kg on a dry weight respectively. Calcium, nitrogen and potassium were well predicted by NIRS in both alfalfa and white clover samples.

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.

Results from field experiments with mobile pests and air-borne pathogens are subject to bias as a result of inter-plot interference. Serially balanced designs (SBDs) allow interference to be estimated but other designs may be better for decreasing such effects. To investigate this, systematic replicated designs, comparing sprays applied at different times to control powdery mildew of spring barley, were sited in 2 years alongside SBDs testing similar treatments. Yields of grain and assessments of mildew on the leaves were analysed. Results from the balanced designs provided strong evidence of interference in both years but not in a third (when the systematic design was omitted). Estimates of treatment effects from the systematic designs were often, but not consistently, greater than corresponding estimates from the SBDs. A method of analysis from Draper & Guttman (1980) was adapted to produce estimates of the differences between treatments as if applied to all plots of an experiment; this showed larger differences between treatments than the conventional analysis in 1975 and 1976 (when there was appreciable interference), but failed in 1977 when interference was slight. This method fails when applied to the systematic designs; SBDs (which are a subset of all designs in randomized blocks) are probably optimal for this type of analysis. The difficulties of analysing data in the form of percentages or proportions (with consequent non-orthogonality) are discussed.

Continuous honeycomb selection and testing in the absence of competition in a single environment, resulted in the isolation of recombinant inbreds in tomato that outperformed the hybrid only in that particular environment. Alternating selection and testing in two environments (open field v. glasshouse) reduced selection efficiency, by preventing exploitation of the whole constellation of genes contributing to heterosis. Selection in the F2 generation was most critical, as evidenced by the appearance of recombinant lines outperforming the hybrid as early as in the F3 generation. Exploitable genetic variation existed in advanced generations and even after the point of achieving theoretical homozygosity (F7 generation). In the future, and in order to fully exploit the unique possibilities offered by the honeycomb methodology (control of soil heterogeneity, high selection pressures, crop yield components), selection for reduced GE interaction should be practiced simultaneously over the target environments of adaptation.

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).

Tocopherols are the most important compounds having antioxidant activity in sunflower seeds. The objective of the present research was to study the genetic and environmental variation for tocopherol content and composition in sunflower. Thirty-six sunflower hybrids were grown at 13 locations across all major areas of sunflower cultivation in southern Spain. Seed yield, 100 seed weight, oil content and tocopherol content and composition were determined. Tocopherol content ranged from 314·5 to 1024·5 mg/kg seed and from 562·8 to 1872·8 mg/kg oil. The tocopherol fraction was largely composed of alpha-tocopherol, which accounted for 88·4% to 96·3% of the total tocopherols. Both genotypic and environmental effects were significant for tocopherol content and composition. For alpha-, beta- and total tocopherol content, the effect of the genotype was larger than that of the environment, whereas the latter had a greater effect on gamma-tocopherol content. Genotype×location interaction was significant for alpha-, gamma- and total tocopherol content. Tocopherol content was not correlated with seed oil or seed yield, indicating the possibility of selecting for this trait without affecting the performance of the genotypes.

By providing both spatial and temporal information remote sensing may function as an important source of data for site-specific crop management. This technology has been used for nitrogen application strategies to obtain optimum yield and grain quality. Here, the objective was to use early repeated remotely sensed multi-spectral data to predict grain yield and quality for winter wheat (Triticum aestivum L.) and spring barley (Hordeum vulgare L.). The crops were sown with two different seeding rates and a wide range of nitrogen strategies were applied. Multi-way partial least squares regression (N-PLS) was used to predict grain yield and protein content. The results were compared with unfold-PLS1 and PLS1 using reflectance data from the last measurement day. Both single reflectance wavelengths and selected vegetation indices were used simultaneously. The results reveal that all models can make a good prediction of yield in both crops with unfold-PLS1 and N-PLS as the best. However, estimation of grain protein content at harvest was very poorly determined in barley, as no relation between the reflectance measurements and barley protein content was obtained. The relation between reflectance measurements and protein content was slightly better in wheat, where especially N-PLS improved the prediction of grain protein content. The overall conclusion of the present experiments is that data from repeated measurements of reflectance used in multi-way partial least squares regression before heading improved the prediction of grain yield and protein content in wheat and barley.

The efficiency of the triple test cross (TTC) and the six-population biometrical analyses was compared in terms of assessing and quantifying the components of genetic variance for two faba bean crosses: Triple White×Giza 843 and NA112×Giza 429. Several traits were studied including days to first flower, plant height, branches/plant, pods/plant, seeds/pod, 100-seed weight and seed yield/plant. The results supported the triple test cross biometrical approach as it uses first degree statistics and can be applied to any population irrespective of its genetic architecture. Absence of a scalar relationship between triple test cross families (orthogonality) ensures independence between means and variance with no restrictive assumptions. Both methods provided evidence for epistasis, and both additive and dominance genetic components in the genetic control of the studied traits.

Cluster analysis has been commonly used in genotype-by-environment (G×E) analyses, but current methods are inadequate when the data matrix is incomplete. This paper proposes a new method, referred to as two-stage clustering, which relies on a partitioning of squared Euclidean distance into two independent components, the G×E interaction and the genotype main effect. These components are used in the first and second stages of clustering respectively. Two-stage clustering forms the basis for imputing missing values in the G×E matrix, so that a more complete data array is available for other G×E analyses. Imputation for a given genotype uses information from genotypes with similar interaction profiles. This imputation method is shown to improve on an existing nearest cluster method that confounds the G×E interaction and the genotype main effect.

In order to quantify the radiation hazard to humans through food, both migration and distribution of 95Zr in Chinese cabbage/soil system were examined by using the radioisotope tracer technique. When 95Zr was administered with simulated irrigation or simulated rainfall, 95Zr was detected in every part of Chinese cabbage, which indicated that 95Zr could be translocated to above-ground parts. Although concentrations of 95Zr in different parts of Chinese cabbage were different in the two treatments used in the present study, the patterns of 95Zr distribution in different parts of the plant were similar. Concentration of 95Zr in each part of Chinese cabbage followed the order of root>leaf>lower part of petiole>upper part of petiole>bud in the case of simulated irrigation. Moreover, the 95Zr could be accumulated in leaves after being taken up by roots. In the simulated irrigation treatment, 95Zr concentrations were 1·7 and 2·9 times higher in the leaf than in the petiole and bud, respectively. In the case of simulated rainfall, a portion of applied 95Zr precipitated on the above-ground parts of Chinese cabbage, which led to a higher concentration here than in the case of simulated irrigation. The results of the present study clearly indicate that there is a distinct possibility that foodstuffs produced in the 95Zr-contaminated area are radioactively contaminated. More than 90% of total 95Zr in soil was retained in the upper layer (0–8 cm), which indicated 95Zr could not easily move downwards because of strong adsorption to soil.

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).

Experiments were designed to examine differences in some morpho-physiological characters among wheat genotypes in response to drought stress at anthesis and maturity and to determine the relationships between these characters. In three sets of experiments, one set was evaluated under well-irrigated conditions and two sets under drought stress conditions by developing terminal drought stress at anthesis in one set and at maturity in the other, for 2 years. Genotypes differed in their response at both stages of plant growth for grain yield, days to heading, excised-leaf water loss, leaf membrane stability and relative water content under drought stress. Under irrigated conditions differences in the genotypes for water retention traits were not clear. There were significant genotype×environment interactions. Terminal drought stress resulted in reduced mean values and variability for all characters. The varieties WH 147 and WH 147(U) showed a combination of drought resistance, water retention and high grain yield, whereas C 306, Kharchia 65 and Hindi 62 showed a lower percentage injury in plasma membrane and better water retention in the leaves. Drought resistance index was associated with other characters.

Sodic soils are widespread, especially in the Indo–Gangetic plain. Amelioration with gypsum is effective, especially when combined with growing a crop of rice. However, it has proved difficult to generate new varieties of sodic-tolerant rice, because of the difficulties of screening – other than in the field, where spatial variation of sodicity is notoriously high. Growing plants at high pH in solution culture in a controlled environment is problematic, because of the effects of pH on nutrient availability. This study evaluated a system of growing rice in a nutrient solution with added Tris but without minor nutrients, which were supplied in a foliar spray. Performance was evaluated from the change in weight and in appearance and correlated with performance in soil. Growing rice in the presence of Tris (4 mM, pH 8·6) provides a means of evaluating genotypic differences in response to sodicity.

Nutrient intake, digestibility and live-weight changes were compared for groups of grazing cattle on two Swiss Alpine pastures in different regions (R1 and R2; both >1500 m above sea level) during 2 years (1997 and 1998). The R1 site was an improved pasture, while R2 was an unimproved pasture of poor nutritional quality. Replicated over 2 years, R1 groups comprised four Scottish Highland suckler cows together with their calves and four Brown Swiss dairy cows (17·8 kg/day milk) kept at high stocking rates (approx. 7 cows/ha) in short rotations (intensive management system). R2 groups comprised four Highland cows with calves managed at low density (approx. 0·4 cows/ha) and set-stocked (extensive management system). Grazing seasons lasted 77 days at R1 and 127 days at R2. Intake, digestibility and faecal excretion were estimated by the slow-release alkane indicator method. Average dry matter intakes in kg/day and g/kg W0·75/day (in parentheses) were 17·4 (151) for dairy cows at R1 and, significantly lower, 12·7 (133) and 11·1 (111) for beef cows at R1 and R2, respectively. Herbage dry-matter intake of calves was 1·2 kg/day at both locations. Calf weight gains measured over 77 days (0·69 kg/day) were similar at the two sites and thereafter declined only slightly at R2. The N content of the herbage selected was similar in the two regions, but in other respects the herbage at R2 was of significantly poorer nutritive quality as indicated by the lower digestibility of organic matter and neutral detergent fibre at R2 compared with R1. Through feed selection, nutrient intake by beef cows was sufficient to gain weight. In contrast, dairy cows at R1 lost on average more than 50 kg of weight. Calculations were made and discussed regarding N utilization and urinary N loss, and measured faecal N and mineral excretion to allow a quantitative assessment of nutrient returns to the sward. We conclude that Highland beef cattle make poorer use of improved Alpine pasture than dairy cows though they utilize pastures of poor nutritive quality under extensive management without loss of productivity.

Conception and lambing rate, and litter size were studied on data from a flock of Horro sheep. The CATMOD and GLM procedures of SAS were used for the analysis of these traits. A sire, direct additive genetic and a repeatability animal model were employed to obtain estimates of heritability and repeatability for litter size. The results obtained showed that year of mating, age and weight of ewes at mating and number of previous parities had significantly (P<0.01) affected the rate of conception and lambing while weight of rams at mating has shown no significant effect (P>0.05). An increase in both conception and lambing rates was observed with the increase in weight of ewes up to about 36 kg and declined thereafter. Ewes which previously had no or one parity had lower conception and lambing rates compared with ewes in later parities. However, a decline in both conception and lambing rates was also observed in old ewes. Year of lambing, parity and weight of ewes at mating had a highly significant (P<0.01) effect on litter size. The overall mean litter size in the flock was 1.34 with annual means ranging from 1.18 to 1.55. Litter size increased with parity from 1.26 in primiparous ewes to 1.44 for ewes of parities five and above. With respect to weight of ewes at mating, litter size increased by 2.5% for each kg increase in weight at mating. The estimates of direct heritability (h2) for litter size were 0.17, 0.11 and 0.06 under the sire, direct animal and repeatability models. Repeatability was estimated to be 0.12. Since heritability and repeatability estimates of litter size are low, genetic improvement by selection may not bring sizeable impact in increasing litter size. Therefore flock management for optimal age structure and optimal weight of ewes at mating should receive due consideration to improve rates of conception, lambing and litter size in Horro sheep.

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.

In Volume 136, 407–426, you published a paper entitled ‘Responses of potato (Solanum tuberosum) to potassium fertilizers’ by M. F. Allison, J. H. Fowler and E. J. Allen. We consider that the authors' conclusions were not justified and they have mis-interpreted and criticized earlier published work. One of their criticisms is levelled at the use of exchangeable potassium (Kex – rapidly plant-available K) to categorize soils on the basis of the likely response of crops to an application of potassium (K) fertilizer. While Kex is not perfect, it is the best rapid method currently available (Johnston & Goulding 1990). To support their contention about Kex, the authors quote in Table 15 data from Rothamsted experiments done in the late 1950s and early 1960s. They state that despite the large amounts of K applied in fertilizers and manures the effect on Kex was relatively small. This comment fails to recognize that it is the K balance (K applied minus K removed) that must be related to Kex, not the K applied, and the inevitable transfer of part of the K balance from Kex to fixed K (less readily available K). Warren & Johnston (1962) showed that on these soil types as much as 60% of the K balance is rapidly transferred to fixed K.

The mechanisms and host plant responses that are indicative of tolerance to the African rice gall midge, Orseolia oryzivora Harris & Gagne were investigated in four promising donor rice cultivars, Cisadane, Bw 348-1, Tox 4093-17-1 and ITA 306 (local check), in a screen house at the International Institute of Tropical Agriculture (IITA), Ibadan, Nigeria. Results indicated that Cisadane was tolerant to infestations on the basis of higher (P<0.05) percentage seedling survival, production of significantly higher number of fertile tillers, productive panicles and significantly higher grain yield per infested plant than the control. Both single infestation at one larva per plant and adult infestation once at 14 days after seeding were positively correlated to higher fertile tiller production per infested plant (at 80 days after transplanting) and higher grain yield per infested plant at maturity. The grain yield per infested plant was significantly higher (P<0.05) in the tolerant variety (Cisadane) than in the control.

A study of the physiological responses and energy expenditure of goats was carried out from June 1999 to May 2000 by conducting two experiments: one on bucks maintained on stall feeding in autumn 1999 (Expt 1) followed by year-round grazing on native ranges over three seasons: monsoon, winter and summer (Expt 2). Physiological responses and energy expenditure (EE) measurements of housed and grazing goats were recorded at 06.00 h and 14.00 h for 5 consecutive days in each season. Goats were fixed with a face mask and meteorological balloon for collection of expired air and measurement of EE. Respiration rate (RR) at 06.00 h was similar in all seasons (14 respiration/min) except in the monsoon, where a significantly (P<0.05) higher value (26 respiration/min) was recorded. At 14.00 h, RR was higher in monsoon and summer (81 and 91 respiration/min) than in winter (52 respiration/min). Irrespective of the season, heart rate (HR) was higher at 14.00 h (86 beat/min) than at 06.00 h (64 beat/min). The rise of rectal temperature (RT) from morning (06.00 h) to peak daily temperature (14.00 h) was 0.9 °C in housed goats in autumn and 1.0, 2.1 and 2.0 °C in grazing goats during monsoon, winter and summer, respectively. The mean value was 1.7 °C. Skin temperature (ST) was lowest in winter (30.1 °C) and highest at 14.00 h in summer (40.3 °C). Energy expenditure of goats at 06.00 h was 32.7 W in winter and significantly (P<0.05) increased to 52.0 W in summer and 107.8 W in monsoon. At 14.00 h, EE was 140.2 W in winter and increased to 389.0 W and 391.3 W respectively in monsoon and summer. It is concluded that monsoon and summer are both stressful seasons in semi-arid regions. Animals should be protected from direct solar radiation during the hottest hours of the day to ameliorate the effect of heat stress.

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.