Three experiments were conducted to determine the value of foliage from three tropical legume trees as low level protein supplements to napier grass diets for growing ‘Kacang’ goats. The average crude protein concentration in the napier grass was 12%.

Napier grass and foliage of the legume trees Gliricidia maculata, Leucaena leucocephala and Sesbania grandiflora were subjected to in situ microbial fermentation and subsequent treatment with acid-pepsin solution. The levels of N solubilized after 2 h incubation were 46 and 43% for napier grass and sesbania respectively, which were higher (P < 0·05) than those for gliricidia and leucaena (27%). Rates of protein disappearance between 2 and 24 h incubation in the rumen averaged 2·6%/h for the legumes and 1·0%/h for napier grass. The proportion of water-insoluble, rumendegradable protein from the legumes was larger (P < 0·05) than that from napier grass.

Napier grass intake by goats supplemented with gliricidia or leucaena at 15% of the dry-matter intake from napier grass was lower (P < 0·05) than that of controls receiving no legume supplement. Napier grass intake did not differ between controls and sesbania-supplemented goats. There was no difference among diets in total dry-matter intake, intake of cell wall constituents or digestibility. Average daily gain for control goats was – 1 g/day as compared with 21 g/day for supplemented goats.

The feeding of formaldehyde-treated soya-bean meal (F-SBM) as a supplement to either napier grass or napier grass–legume diets increased (P < 0·05) intake of dry matter and weight gain of goats. Napier grass intake of animals supplemented with only F-SBM was higher (P < 0·05) than that of control animals. The efficiency of N utilization from F-SBM was higher than that in the legumes, but replacement of legumes by F-SBM above 4% F-SBM feeding had no effect on weight gain or efficiency of utilization.

It was concluded that napier grass of 6–8 weeks' regrowth with 12% crude protein did not provide sufficient protein for growing goats owing to inefficient protein utilization. The increase in efficiency of protein utilization on supplemented diets is mainly associated with the larger proportion of water insoluble, rumen degradable protein and possibly acid-pepsin soluble protein in tropical tree legumes.

Forty-one cows were used to determine calving intervals, intervals from calving to conception and pregnancy rates at 60–90 days postpartum for suckled and nonsuckled Bunaji cows. Twelve of the cows (six suckled and six non-suckled) were used to study the serum progesterone concentrations during the postpartum period. The mean intervals from calving to conception were 232·5 and 72·6 with calving intervals of 512·5 and 352·6 days for suckled and non-suckled cows, respectively. Pregnancy rates at 60–90 days postpartum were 21·1 and 72·7% for suckled and non-suckled animals, respectively. The overall mean calving interval and interval from calving to conception for all cows were 426·7 and 146·7 days, respectively, with a conception rate of 48·8%.

Based on serum content of progesterone and rectal palpation of ovaries, one of six suckled cows resumed ovarian activities within the first 90 days of calving with peak progesterone of 0·7 ng/ml. Four of six non-suckled cows resumed cyclic activities and conceived within the same period. Two of the four cows conceived at the first postpartum cycle and the remaining two conceived at the second cycle. The serum progesterone concentrations of the cows ranged from 0·1 to 6·9 ng/ml during the nonfertile cycle and 0·1 to 15 ng/ml at pregnancy. It is concluded that suckling interfered with ovarian activities and thus conception during the postpartum period, resulting in a prolonged calving interval.

Blood samples were collected at 12-week intervals from 12 to 72 weeks from a total of 221 growing Friesian and Jersey calves and assayed for plasma concentrations of free fatty acids (FFA), ketones, glucose, calcium, phosphorus, magnesium, copper, albumin and globulin. Sixty-six of the animals could be allocated to genetically high and 73 to genetically low milk producing lines on the basis of being sired by the ‘best’ or ‘worst’ nationally available progeny tested sires. All animals were housed indoors and fed a complete pelleted diet ad libitum. There were no differences between genetically high and low milk production lines for any blood constituent and no useful indicators of genetic merit for milk production in later life. There were no differences between breeds for metabolites related to energy status (FFA, ketones, glucose). Friesians bad higher magnesium and lower mean copper concentrations than Jerseys and had higher phosphorus concentrations up to 36 weeks. Differences between breeds and ages in mineral concentrations were not related to breed differences in the discrepancy between observed intakes and predicted requirements of minerals. Concentrations of globulins were higher and of albumin lower in Jerseys than in Friesians at 12 and 24 weeks possibly owing to slightly higher disease incidence of Jerseys in early life. There were changes with age in concentrations of all constituents except FFA. There was evidence of genetic variation within breeds and lines for mean plasma concentrations of ketones, copper and globulin. There was no evidence for differences between females and castrates for any blood constituent.

The emergence of seedlings from natural, germinating and selected uniformlygerminated onion seeds was compared in a range of changing patterns of soil moisture. The timing, spread and amount of seedling emergence from seeds in all three treatments were affected by the timing of water availability in the seed bed and these effects differed between treatments.

The rate of seedling emergence in all three treatments under non-limiting soil moisture conditions was correlated with mean temperature, but this relationship was obscured in irrigation treatments where water stress occurred. However, if the seed bed was moist at sowing irrespective of subsequent moisture stress the reciprocals of the time to the start, time to 50% and time to the end of seedling emergence from uniformly germinated seeds were correlated with mean temperature (r > 0·87, D.F. 27).

The results show that if the seed bed is irrigated prior to sowing and soil moisture is maintained during the first 3 days following sowing high levels of seedling emergence with both predictable timing and uniformity can be achieved by sowing uniformlygerminated seeds. Seedling emergence from natural and germinating seeds was much less predictable.

Damage to barley grain cv. Golden Promise was induced in the laboratory by putting seed at 8·7, 14, 18, 22, 26 and 35% moisture content (MC) through a mechanical laboratory thresher for 10, 20 or 45 sec. The extent of visible external damage was greatest at 8·7 and 14% MC with reduced and similar levels of damage after handling at 18–35% MC. At moisture contents up to and including 26%, seeds could tolerate extensive mechanical damage with little effect on seed quality. Seed germination and seedling vigour were, however, reduced after handling at 35% MC despite similar levels of external damage to those seeds handled at 18, 22 and 26% MC. Samples of grain of cv. Triumph produced by whole-crop harvesting included mainly slightly damaged seeds with little effect of harvest moisture content, which ranged from 22·5 to 44%, on the incidence of damage. Seed germination and seedling vigour increased when seeds were harvested at progressively lower moisture contents, with the largest increase between 36% MC (56% germination, 6·1 vigour rating) and 29·5% MC (94% germination, 7·8 vigour rating). The seed quality of whole-crop harvested seed at 29% MC was similar to that of combined seed harvested at the same moisture content. It is suggested that 30 % is the maximum harvest moisture content at which commercially acceptable seed may be produced by the whole-crop harvesting method.

A 4 x 4 latin-square design experiment was carried out to determine the effects of increasing nitrogen (N) intake by feeding diets containing increasing amounts of soyabean meal upon the digestion of organic matter (OM) and N by cattle equipped with rumen and duodenal cannulae. A basal diet (B) containing 600 g ground barley and 400 g grass silage/kg diet and three diets (BS1, BS2 and BS3) in which increasing amounts of the barley were replaced by soya-bean meal were fed. The mean daily intakes of OM and N when each diet was fed were 4·56, 4·55, 4·30 and 4·52 kg OM and 920, 114·7, 138·3 and 164·1 g N for diets B, BSl, BS2 and BS3 respectively.

Neither the amounts of OM entering the small intestine nor those voided in the faeces were altered by the diets fed. Thus the mean apparent OM digestibility for all the diets fed was 0·74 + 0·013 and the proportion of digestible OM intake apparently digested in the rumen was 0·77 + 0048.

Mean daily concentrations of ammonia N in the rumen were significantly (P < 0·001) increased from 38 mg N/l (diet B) to 129 mg N/l (diet BS3) as N intake increased.

The quantities of non-ammonia N and of amino acid N entering the small intestine were not significantly (P >0·05) increased as more soya-bean meal was added to the diet, although diet BSl supported the greatest flows of N to the small intestine. Thus as more soya-bean meal was added to the diet there were increasing net losses of nonammoniaN(P < 0·01) and amino acid N (P < 0·01) prior to the small intestine. Faecal N excretion was not increased (P > 0·05) as soya-bean meal intake increased and thus apparent N digestibility was significantly (P < 0·01) increased by increasing soyabean intake.

Both the quantities of microbial N entering the small intestine daily and the apparent efficiency of microbial N synthesis within the rumen were increased when diet BSl was fed in comparison with the basal diet (B) and then declined when diets BS2 and BS3 were fed; these increases were not significant. The quantities of feed N entering the small intestine daily were not significantly (P > 0·05) increased as soya-bean meal intake increased; thus apparent feed N degradability in the rumen was significantly (P < 0·01) increased as soya-bean meal intake increased. In contrast, the rates of disappearance of N from each of the components of the diets fed, when incubated in the rumens of the cattle in porous synthetic fibre-bags, were not increased (P > 0·05) as soya-bean meal intake increased.

Inoculation of 3·0 t of fresh Azolla pinnata (Bangkok) per hectare 15 days before transplanting, 10 and 30 days after transplanting produced Azolla mats on the water surface 10, 12 and 15 days after inoculation, respectively. The Azolla growth and N2-fixation before transplanting were more than that after transplanting. Growing Azolla once before transplanting and twice after transplanting produced a total of 51·0–52·8 t fresh Azolla/ha, which fixed 92·8–96·0 kg nitrogen, whereas growing it once before transplanting plus once after transplanting and twice after transplanting produced 35·0–40·0 and 29·0–37·5 t fresh Azolla/h, and fixed 660·–72·4 and 52·5–66·1 kg N, respectively.

Application of Azolla increased the plant height, tillering, grain and straw yields of rice and also the fertility of the soil at harvest. Growing and incorporating Azolla once before transplanting and twice after transplanting of rice increased the grain and straw yields significantly more than applying 60 kg N/ha as urea and showed greater effect on soil fertility.

Growing Azolla before or after transplanting the rice in combination with 30 kg N/ha as urea and Azolla once before transplanting and once after transplanting without incorporation gave responses similar to that obtained by a divided application of 60 kg N/ha as urea. Growing and incorporating Azolla twice after transplanting showed slightly less response than growing it once before and once after transplanting and giving 60 kg N/ha as urea but slightly more than giving 45 kg N/ha as urea. The Azolla pinnata collected from Bangkok and Vietnam when used once before transplanting at equal biomass (15·0 t/ha fresh Azolla) together with a top dressing of 30 kg N/ha as urea showed a similar response in the rice crop.

The relationship between seed rate and use of pesticide (chlorpyrifos and aldicarb) on tiller density and herbage yield of a conventionally established autumn re-seed (i.e. grass sown after a previous grass crop) of Italian ryegrass (cv. RvP) was investigated in small plot trials at three sites in Yorkshire, Berkshire and Devon in August 1984. Plots were also sampled for pests and earthworms. Pesticide enhanced yield at all sites at the first harvest in October 1984, particularly at the low seed rates, but this effect did not persist until the spring harvest in 1985. Tiller density and herbage dry-matter yield increased logarithmically with increasing seed rate. Frit fly was the major pest and the proportion of infested tillers increased linearly with seed rate. Low seed rate in combination with appropriate insecticide was more cost effective than untreated higher seed rates in the establishment of autumn re-seeded Italian ryegrass.

Observations are presented from a crop of sugar beet grown in Cambridgeshire during 1978, and a field trial at Sutton Bonington during 1985 in which the influence of synthetic plant growth regulators (PGRs) daminozide, chlormequat, GA4+7 and ethephon were compared.

Several distinct patterns of growth were evident, being similar for both growing seasons and described by two intersecting straight lines. Early development was characterized by a slow rate of biomass accumulation, a dominance of foliage production with a constant but small root fraction (around 40%), a low specific leaf area and a slow but conservative rate of sucrose fractionation. Later in the season the rate of stand growth was both constant and maximal, the root fraction doubled, specific leaf area increased and the rate of sucrose accumulation rose markedly.

Transitions between developmental phases occurred at various times dependent on variate under consideration. The onset of the main growth period began at the end of June, followed by an increase in the rate of sucrose accumulation about 2 weeks later. Finally, near the end of July, partition of assimilate into the root assumed a faster rate. Changes in the partitioning into both roots and sucrose are discussed in relation to the development of the secondary cambium.

Generally there were no effects of PGRs on biomass accumulation, dry-matter partitioning, specific leaf area and sucrose accumulation. However, daminozide increased early canopy expansion and early dry-matter production but failed to influence biomass or sugar yield.

Spores of Pyrenopeziza brassicae, which are mostly dispersed by rain splash, were trapped 4 m above and 20 m downwind of an oil-seed rape crop. This suggests that not all trapped spores were transported in ballistic splash droplets (100–2000 μm); indeed some were airborne during periods of dry weather following closely after rain. Vertical and horizontal spore concentration gradients corresponded to the gradients expected for spores with fall speeds of between 2 and 5 cm/sec. Atmospheric dispersal calculations suggest that such spores have the potential for transport over considerable distances to other susceptible crops.

Four experiments are reported in which the effects of a range of physiological ages of seed tubers on growth and yield in seed crops and regrowth of the progeny seed were studied. Increasing the age of seed in Home Guard, Arran Comet, Pentland Javelin and Désirée advanced emergence, tuber initiation and early growth but restricted leaf area index and reduced the number of tubers and seed tuber yield. In these varieties increasing the physiological age of seed shortened the dormancy of the progeny seed and slightly increased sprout lengths at replanting but in Home Guard had no effects on field growth and tuber yield.

In a further series of experiments at Tenby seed of five varieties (Home Guard, Red Craigs Royal, Désirée, Maris Piper and Stormont Enterprise) was multiplied over 2 years using husbandry methods designed to produce seed of contrasting ages. Once-grown seed from Tenby which had been planted and harvested early in the season was stored at either 4 or 12 °C and grown again at Tenby before being stored again at either 4 or 12 °C. The seed resulting from this multiplication over 2 years was compared with seed imported from seed-growing areas stored at the two temperatures. The seasons for the two multiplications at Tenby (1975 and 1976) were hot and were followed by an especially cold and late spring yet few differences between seed from Tenby and other areas could be detected. Where seed from different areas entered sprouting temperatures at different times and therefore produced different ages of seed at replanting large effects on yield were found. Storage temperature had large effects on regrowth of tubers in Home Guard, Red Craigs Royal and Stormont Enterprise for storage at 12 °C produced ‘little potato disorder’ in the majority of plants in one storage phase while storage at lower temperature produced full plant stands and yields. The results provided no support for the suggestion that repeated multiplication in warm lowland areas may lead to cumulative deterioration in the performance of seed.

The effects of recalculating P concentrations in spring barley (Hordeum vulgare L. cv. Georgie or Julia) on the basis of tissue water were investigated. Expressing P concentrations in this way altered their apparent behaviour with time. Whereas % P in dry matter declined during growth, P concentrations in tissue water decreased initially but then increased. The rate of increase became more rapid during senescence. Nitrogen and water supplies induced differences in % P in dry matter but these were reduced when P concentrations were expressed on the basis of tissue water. Like % P in dry matter, P concentrations in tissue water were lower in crops grown on a soil that had not received P since 1852. It is suggested that P concentrations in tissue water can provide a method for assessing crop P status that has some advantages over % P in dry matter.

Laboratory studies were conducted on four soils to ascertain the effect of P content and texture on the capacity factor (P buffering capacity) of soils and in turn the effect of these factors combined with moisture content of soil on the diffusion coefficient of P (Dp). A glasshouse experiment was conducted to study the relationship of Dp with P uptake by maize and wheat. The buffer capacity decreased by the application of P in all four soils. There was a significant negative correlation between buffer capacity and Olsen's extractable P but positive correlation with other soil factors. The relative influence of different soil variables on the buffer capacity was in the order: free iron > percentage clay > exchangeable aluminium. The Dp value increased significantly with applied P, the maximum (3·2-fold over control) being in Tolewal loamy sand. The increase in clay and moisture content of soil also increased the Dp value. The drymatter yield and P uptake was significantly correlated with Dp, the r value being higher at later stages of growth of maize and wheat.

An experiment to study the effect of row direction on the light interception, growth and yield of three wheat cultivars sown at three different dates was conducted at Punjab Agricultural University, Ludhiana during rabi seasons 1982–3 and 1983–4. The results showed that sowing in a north-south direction resulted in 0·20 and 0·22 t/ha higher yield than sowing east-west. Bi-directional sowing gave further increases of 0·30 and 0·18 t/ha over north-south direction during 1982–3 and 1983–4 respectively. Late sowing significantly reduced yield.

Incidences of pollination and fertilization were determined and the development of seeds was monitored in spring beans over 2 years. Plant density was varied in the 1st year and irrigation in the 2nd. The incidences of pollination, fertilization and seed development were all independent of plant density. The proportion of ovules that developed as seeds was slightly enhanced in irrigated plots as losses from abortion and from lack of fertilization within fertilized ovaries were both reduced. Autofertility, or spontaneous self-pollination leading to fertilization, led to an increase in the overall incidence of fertilization. Three autofertile stocks were up to 11% more pollinated and fertilized than two partly autofertile ones which, in turn, were up to 20% more than two non-autofertile, long-podded stocks. A closed-flower population was 30% less fertilized than the long pods and was insufficiently autofertile to allow an adequate number of pods to set on the lower flowering nodes. Three stocks, one autofertile, one with terminal inflorescences (ti) and the third with both characters, were subject to particularly high losses of fertilized ovules from abortion, 27–35%, while few ovules, 12% or less, aborted in closed flowers and long pods. Failure of seeds to mature in long pods was associated primarily with the low proportion of ovules fertilized within fertilized flowers, rather than with abortion of the fertilized ovules.

Energy budgets and estimates of forage intake requirements were developed for adult camels, cattle, sheep, and goats managed by nomads in the arid Turkana District of north-western Kenya. The estimates were developed by combining our field data on livestock activity patterns, diet quality, weight changes and milk yields with literature based estimates of the associated costs and efficiencies. On an annual basis, the average animal walked 17 km/day and had a total metabolizable energy (ME) allocation of 47% for basal metabolism, 16% for travel, 14% for other activities, and 23% for production. Season and species influenced patterns of energy demand and allocation. Average daily ME requirements ranged from 8·7 MJ (sheep) to 76·7 MJ (camels). ME demand for all species peaked during wet (April-May) or early-to mid-dry periods (June-October), and decreased considerably in the late-dry season (November-March). In the wet season the average sheep or goat allocated 45% of its ME budget to production of milk and gain, followed by cattle (36%) and camels (25%). All species were more similar in ME allocation for production during the late-dry season (7–13%; all to lactation), yet patterns of weight loss during this time indicated that camels experienced the lowest degree of negative energy balance. On an annual basis, camel budgets were the most deviant, as they allocated relatively more ME to activity and relatively less to basal metabolism or weight gain. Estimates of forage dry-matter intakes (per unit live weight per day) ranged from 3·8% (cattle, camels) to 4·6% (sheep, goats) throughout the year, and intakes declined for most species by an average of 50% from the wet to late-dry intervals. This approach has revealed ecological differences among livestock species that help explain the utility of multi-species holdings in this system.

The ability of mepiquat chloride and chlormequat growth retardants to modify grain yield components and stem length in two contrasting spring barley cultivars was evaluated in 2 years of small scale field experiments in central southern England. Interactions with plant population density and sowing date were studied.

The mid-tall cv. Koru was more responsive than the shorter high tillering ‘erectoides’ cv. Goldmarker. Early treatments of mepiquat chloride (applied before the start of main shoot stem elongation) on Koru raised grain yield/plant in both years. Early treatments with chlormequat and later applications (during main shoot stem elongation) of either retardant were largely ineffective. Yield increases were achieved by raising the number of spikes/plant along with the number of grains/spike and the above-ground biomass in certain later-formed, lower ranking shoots.

A medium plant population density (250 plants/m2) allowed the best response to early treatment with mepiquat chloride, as did a normally-timed sowing in contrast to a late one. Retardant-induced improvements in yield components in Koru were positively correlated with plant height, the result of over-compensation in the length of upper internodes.

It appears that effective treatments reduced the dominance of the main shoot during tillering, allowing greater initiation and survival of florets (grain sites) in smaller shoots.

Forty-nine and 58 Damascus goats were used in each of two trials, respectively. Goats were randomly allocated 2 days post-partum to twin-suckling (TS), singlesuckling (SS) and no-suckling (NS) kids treatments. In trial 1, artificially reared kids were divided into two groups fed either on ewe-milk (25·8% fat, 24·2% protein) or on calf-milk (15% fat, 22·5% protein) replacer. In trial 2, all artificially reared kids were fed on ewe-milk replacer. The ewe- and calf-milk replacers were reconstituted in the ratio of 1 part powder to 5 or 4 parts (by weight) of water, respectively.

Separation of kids from their dams reduced total milk yield (means of two trials) until weaning (TS 194, SS 176, NS 121 kg/goat) and from weaning to 90 days of lactation (TS 95, SS 89, NS 70 kg/goat). On the other hand, separation of kids increased marketable milk yield until weaning (TS 68, SS 99, NS 121 kg/goat). Marketable milk during the period 3–90 days post-partum was similar for NS and SS goats (TS 163, SS 188, NS 191 kg/goat). Goats suckling two kids suffered greater weight losses (TS 78, SS 44, NS 6 g/day). Goats suckling two males produced more milk until weaning than all other twin sets. Differences in concentrate intake between group means of TS and SS were smaller compared with the NS group (TS 2·26, SS 2·08, NS 1·86 kg/goat per day).

There were no differences in weaning weight and weight gain from birth to weaning between kids reared on milk replacers. However, four kids on the calf-milk replacer died and two more were excluded from the data because of severe scouring. Single suckling kids gained more weight until weaning than TS and those reared artificially (AR) on ewe-milk replacer (SS 11·1, TS 9·1, AR 9·3 kg/kid). Furthermore, males consumed more milk than females (males 74, females 64 kg/kid) and SS more than TS kids (SS 75, TS 63 kg/kid).

It is concluded that SS and NS treatments increase commercial milk yields compared with the TS goats, but NS should not be recommended because of an adverse effect on pre- and post-weaning lactation performance.

Eight forage rape cultivars were grown in replicated trials in 1980, 1981 and 1982; the plots were either inoculated to promote early infection with powdery mildew (Erysiphe cruciferarum) or they received one application of fiuotrimazole (in 1980) or triadimefon (in 1981 and 1982) to control mildew.

Mildew infections first appeared during August and increased rapidly during September to give highly significant differences between cultivars for the percentage leaf area infected in October; cv. Lair had the least mildew and cvs Samo, Early Giant, Bishop and Winfred were most severely infected. Regression analyses were used to investigate the increase in mildew over time in 1980 and 1981. No clear pattern of disease development was evident in 1980, but in 1981 the increase in mildew was predominantly linear and in untreated plots the greatest increase occurred in cvs Winfred, Samo and Bishop and the least in cv. Lair. Mildew was reduced in each year (P < 0·001) on fungicide treated plots and the mean fresh weight yield increase of 4·61 t/ha from treated plots was attributed mainly to the control of E. cruciferarum.

Fungicide treatment had little effect on % organic matter (OM), % digestible organic matter (DOMD) or concentration of thiocyanate ion (SCN-); both % nitrogen (N) and concentration of S-methyl cysteine sulphoxide (SMCO) were reduced in fungicide-treated plots in 1981, and N was also reduced in 1982. The mean concentration of SCN- from treated and untreated plots over 3 years was least in cv. Samo (14·90 mg/100 g D.M.) and greatest in cv. Lair (22·15 mg/100 g D.M.). The response in yield and quality factors to fungicide treatment is discussed in relation to the control of powdery mildew and other, possibly phytotonic, effects.

From a mixed group of cross-bred steers slaughtered at the same age, up to 12 carcasses of similar weight from each of the five conformation classes were chosen using the European Economic Community (EEC) scale for the classification of carcasses of adult bovine animals. In the hindquarter of carcasses with better conformation the ratio of muscle to bone was higher with less internal fat and more subcutaneous fat, muscles were heavier and blockier, both the carcass and leg length were shorter. Short-thick muscles were associated with short-thick bones. The results indicate that the EEC scale is a useful method to discriminate between carcasses differing in composition. It is suggested that differences in muscle: bone ratio in cattle could reflect differences in the structure and shape of bones. The conclusions remain tentative until they are confirmed on a larger number of carcasses.