bluuebunny/crossref_metadata_2025 huggingface dataset:
Effects of the inclusion of treated jack beans (Canavalia ensiformis) and the amino acid canavanine in chick diets
Authors: Belmar R. , Morris T. R.
Published: March 2009

Three experiments were conducted in Mérida, Mexico, between 1987 and 1990 in which jack beans, treated in various ways, were included in chick diets at the rate of 300 g/kg diet. The diets were balanced by appropriate supplementation to provide the same concentrations of energy, minerals, vitamins and principal essential amino acids as control diets based on maize or sorghum and soyabean meal. Boiling jack beans or soaking and shaking them and the combination of boiling with soaking and shaking were studied with a view to removing or inactivating toxic factors and enhancing the utilization of the beans as a livestock feed. A fourth experiment was conducted to evaluate the contribution of canavanine to the deleterious effect observed when broiler chicks are fed diets containing treated jack beans and to examine the effect of canavanine on the efficiency of protein retention of broiler chicks.

Boiling for 1 or 2 h reduced the toxicity of jack beans, but chick growth rate was only half that of controls. The combination of boiling, followed by soaking and shaking, removed most of the jack beans’ anti-nutritional factors, but some toxic effects were left in the beans, causing a depression of c. 10% in feed intake and growth rate. Growth, feed intake and protein utilization of chicks were not affected when canavanine was added to a sorghum-soyabean diet at a level (3·5 g/kg diet) which matched the canavanine present in a diet containing 300 g/kg boiled jack beans.

It was concluded that boiling was a satisfactory procedure for the inactivation of the heat-labile lectins in jack beans and that soaking and shaking was an effective method of reducing canavanine and the haemolytic activity of the saponins in jack beans. However, canavanine was found not to be the main toxic or anti-nutritional factor present in jack beans.
Grain yield in determinate and indeterminate cultivars ofVicia fabawith different plant distribution patterns and population densities
Authors: Stützel H. , Aufhammer W.
Published: March 2009

A determinate and an indeterminate cultivar ofVicia fabawere grown in the field to study the effects of two different plant densities and three plant distribution patterns on yield formation. The relationship between crop growth rate during flowering and the number of pods produced was identical in both cultivars. The higher growth rates of the indeterminate cultivar and of dense stands were associated with higher pod numbers. Average crop growth rates in the period between flowering and 30 days thereafter were related to the number of mature seed-containing pods. This relationship was similar in both cultivars except that the determinate cultivar aborted seed-containing pods as late as 40–45 days after flowering when grown at the low density. Rates of seed filling for both cultivars were similar at the low density (c1·4 mg per °C per day per pod), but were larger for the determinate cultivar at the high density. The annual differences in seed weights per pod were not related to seed filling rates. Grain yields and harvest indices were generally lower in the determinate than in the indeterminate cultivar, but high plant density increased seed yields of the determinate more than of the indeterminate, because of an increase in harvest index. Plant distribution pattern had no significant effect on the above characters.
A comparison of methods for determining the concentration of extracellular peptides in rumen fluid of sheep
Authors: Wallace R. J. , McKain N.
Published: March 2009

Samples of rumen fluid were removed from pairs of sheep on four grass-hay-based diets 7 h after feeding. Micro-organisms were sedimented by centrifugation and the cell-free supernatant was treated with perchloric acid (PCA) to precipitate protein. The remaining fluid was analysed for peptides by several methods to determine how much peptide escaped degradation. Ammonia interfered with analysis by amino group reagents, especially ninhydrin. In this respect,o-phthalaldehyde and trinitrobenzene sulphonic acid were more specific and more useful than ninhydrin. Use of all these reagents showed that significant quantities of amino groups (equivalent to up to 153 mg amino acid N/1 of rumen fluid) were released by hydrolysis of the PCA extract with 6 M-HCI for 24 h. However, fluorescamine analysis indicated that the peptide content of the unhydrolysed PCA extract was < 3 mg N/1. The true amino acid content of different extracts was resolved by chromatographic amino acid analysis: the sum of individual amino acid concentrations in acid-hydrolysed PCA extracts of extracellular rumen fluid ranged from 7·8 to 14·5 mg N/1. Thus most of the free amino N released by hydrolysis of the PCA extract was not from amino acids, and most of the amino acids that were released were originally present in a form that did not react with fluorescamine. Although none of the methods gave a reliable estimate of peptide concentrations, amino acid analysis provided an upper limit. It was therefore concluded that peptide concentrations in extracellular rumen fluid are much lower than indicated by previous ninhydrin estimations, and that little dietary peptide escapes degradation for a prolonged period in the rumen.
Evaluation of the nitrogen contribution of legumes to subsequent cereals
Authors: Danso S. K. A. , Papastylianou I.
Published: March 2009

The effects of a preceding (1986/87) season's crop of vetch (Vicia saliva) or oats (Avena sativa), either singly or as two different mixtures, on the nitrogen uptake and growth of a succeeding barley crop (Hordeum vulgare) were examined in Cyprus in 1987/88, on field plots previously labelled (1984/85) with 15N enriched organic matter. Grain as well as the vegetative material were harvested before planting the barley. Barley after vetch accumulated 61 % more nitrogen than barley after oats, while, for the mixtures, the nitrogen yields in the succeeding barley crop did not differ significantly from those of barley grown after oats. The 15N enrichment in barley indicated that fixed N2 from vetch contributed little nitrogen to the available soil nitrogen pool and to the nitrogen in barley. Most of the increased assimilation of nitrogen in barley following vetch (compared to barley after oats) was attributable to a greater availability of soil nitrogen arising from the lower soil nitrogen uptake by the preceding vetch than oats. The dry matter yield of barley following vetch was 84% higher than for barley after oats, while barley after the vetch-oats mixtures yielded 38–54% higher than barley following oats. It was concluded that greater nitrogen availability to the cereal following the legume was not the sole cause of the dry matter yield responses observed.
Nutrient cycling and losses based on a mass-balance model in grazed pastures receiving long-term superphosphate applications in New Zealand: 2. Sulphur
Authors: Nguyen M. L. , Goh K. M.
Published: March 2009

Sulphur (S) cycling and losses in irrigated, sheep-grazed pastures receiving annual superphosphate (SP) applications for 35 years at rates of 0, 188 and 376 kg/ha were studied using a mass-balance approach which accounted both for S inputs to and outputs from the soil-plant-animal system. Total recoveries of applied S in the 188 and 376 kg SP/ha treatments were estimated to be 35·2 and 21·2% respectively. Over 65·0% of the applied S was not recovered, and this was attributed to leaching losses beyond the major rooting zone (0–300 mm), lateral S transfer by irrigation water and cxcretal S transfer to stock camps. The lower S recovery in the 376 compared with the 188 kg/ha per year treatment was probably due to a higher accumulation of soil phosphorus (P), which might have competed with sulphate (SO42-) for adsorption sites on soil colloids. Superphosphate applications resulted in the accumulation of soil organic S (S0) fractions (hydriodic acid-reducible and carbonbonded S) to a soil depth of 300 mm in both camp and non-camp areas. However, an increase in SP applications from 188 to 376 kg/ha per year did not lead to a further accumulation of soil S0 fractions. Approximately 50% of this additional S input was estimated to be leached beyond the 300 mm depth. The presence of soil So fractions at 300 mm soil depth, especially in camp areas, suggests that leaching occurred, involving not only SO42- but also So fractions from soil, plant litter, root residues and animal excreta, as the soil had a low SO42- retention capacity. These leaching losses may limit the ability of soil S reserves to sustain adequate S for pasture production when S fertilizer application is withheld.
Body weight and wool production in grazing sheep given access to a supplement of urea and molasses: intake of supplement/response relationships
Authors: Nolan J. V. , Norton B. W. , Murray R. M. , Ball F. M. , Roseby F. B. , Rohan-Jones W. , Hill M. K. , Leng R. A.
Published: March 2009

A technique for estimating the intake of liquid supplements by individual, grazing animals was used in a trial with 200 sheep grazing poor quality pasture and given access to a urea-molasses supplement (19%, w/v).

A mathematical procedure was developed to estimate intake of supplement based on measurements of the accumulation of tritiated water (TOH) and its rate of turnover in the body of each animal after a TOH-labelled mixture had been available for a period of 7 days.

In calculating the level of intake of labelled supplement, it was assumed that each animal ingested the mixture once daily over the 7-day period, since animals were observed to take the supplement daily and the daily loss of supplement from the dispenser was noarly constant. It was estimated that the combined intakes of the animals accounted for 87% of the known total loss of labelled supplement from the dispenser.

Of the 200 sheep, 97 did not consume any supplement and among the other 103 animals, estimated intake varied from 5 to 550 ml/day.

All sheep lost body weight during the trial, but those consuming the supplement lost significantly less weight, and grew significantly more wool during the period of supplementation, than did the sheep that did not consume the supplement.

A small but significant amount of the variance (13%) in body-weight change and wool growth during supplementation was removed by multiple regression analysis, by including the intake of the supplement, faecal egg count (as an indication of parasite burden) and body weight at the start of the trial, as independent variables. Other factors not studied (e.g., dry matter intake) apparently accounted for a large proportion of the variance.

The relationship between body-weight change and intake of the urea-molasses mixture was compatible with the hypothesis that the supplement was used largely as a concentrate feed, and not solely as a nitrogen supplement.
Seed yield in caraway (Carum carvi). 1. Role of pollination
Authors: Bouwmeester H. J. , Smid H. G.
Published: March 2009

Seed yields of caraway vary considerably between years, indicating that weather affects the yield-determining processes. Pollination could be one of these processes, because pollinator activity and efficiency are negatively affected by cold or wet weather. From 1990 to 1992 at the Research Institute for Agrobiology and Soil Fertility in Wageningen, The Netherlands, field and glasshouse experiments were performed to study the importance of pollination for caraway seed yields and the effects of some environmental factors. Preventing insect pollination by placing gauze cages in field plots reduced the yield of caraway byc. 15–20%, but under normal field conditions > 90% of hermaphrodite flowers were fertilized and additional hand-pollination did not improve yield. Removal of competing umbels enhanced the low seed set percentages in higher-order umbels, indicating that pollination did not limit seed yield in these umbels. Assays suggested that wind transfer, in addition to insects, plays a role in the pollination of caraway. It was concluded that assimilate availability and not pollination limits caraway seed yield.
Intake and digestion in swamp buffaloes and cattle. 3. Comparisons with four forage diets, and with rice straw supplemented with energy and protein
Authors: Kennedy P. M.
Published: March 2009

Intake and digestion by swamp buffaloes (Bubalus bubalis) and crossbred cattle (Bos indicus × B. taunts) of a range of diets were measured in two experiments conducted in north Queensland in 1988. In Expt 1, four animals of each species were offered rice straw ad libitum with a supplement of minerals and urea. The four dietary treatments were (i) no concentrates, (ii)cracked rice grain (900 g/day), (iii) cracked rice grain (900 g/day) plus sunflower seed meal (900 g/day) and (iv) as for (iii) but with 50% of the sunflower seed meal treated with formaldehyde solution. In Expt 2, the same animals were offered two legumes, lablab (Lablab purpureus) and verano (Stylosanthes hamata cv. verano), and two grasses, sorghum (Sorghum bicolor × S. sudanense) and pangola grass (Digitaria eriantha). In Expt 1, voluntary intake of organic matter of buffaloes was 1·22 that of cattle. Concentrate supplementation increased organic matter digestibility and total intake, but did not affect straw intake. Intake of supplements by cattle was poor in the absence of sunflower seed meal. In Expt 2, intake and digestibility was similar in both species but was higher in animals given sorghum compared with the other forages. Total time spent chewing for both species and all diets ranged between 163 and 244 min/kg intake of plant cell wall constituents. The fractional rate of fluid flow from the reticulorumen and the concentration of propionic acid in the rumen fluid of buffaloes were consistently higher than in cattle in both experiments. Cotton and rice straw, placed in polyester bags in situ in the reticulorumen, were more extensively fermented in buffaloes than in cattle in Expt 1. In contrast, there were no differences between animal species in fermentation rates of cotton and ground diets in situ in Expt 2, but a relationship was observed between the relative fermentation of cotton and the relative digesta retention times in the reticulorumen in the two animal species. Microbial biomass, estimated as microbial dry matter per kg dry matter in the reticulorumen, was less (P < 0·05) in buffaloes than in cattle in Expt 1; higher concentrations of protozoa were observed in buffaloes than in cattle in Expt 2. Digesta load in the reticulorumen of buffaloes was c. 0·88 that of cattle. In Expt 1, digesta load was inversely related to digestible organic matter intake. The results were consistent with the hypothesis that energy metabolism and digesta load in the reticulorumen interact in the regulation of roughage intake, but it appeared that the lower loads measured in both species in Expt 2 indicated the operation of an unidentified limitation to intake.
Persistence of herbage treatment effects in barley and consequences for subsequent crop experimentation
Authors: Fairey N. A. , Lefkovitch L. P.
Published: March 2009

A study, conducted in the Peace region of Canada, determined the effects of the stand and management treatments of four herbage experiments (1986–88) on the yield and quality of subsequent crops of barley (Hordeum vulgare L.) harvested in 1989 and 1990. Quantitative relationships indicated that the crop management treatments most conducive to good yield and quality of herbage were also the most beneficial for subsequent high yield and quality of the barley grain. Unless designs orthogonal to those previously used can be found, covariance adjustment procedures are recommended to minimize the residual effects of previous experiments.
Heterogeneity of variance in field experiments: some causes and practical implications
Authors: Krajewski P.
Published: March 2009

Data from 62 field experiments on various crops in 1973–85 at Rothamsted Experimental Station were used to obtain knowledge about the heterogeneity of variance of yield. The results suggest that explaining heterogeneity of variance in terms of a mean–variance relationship is inadequate; better understanding of the patterns of changing variance can be gained by investigating the influence of the experimental factors on the variance. The effects of the factor ‘amount of nitrogen’ on mean yield and on the variance were positively correlated; factors which tend to affect variability but not the mean were identified. Suggestions are given for controlling variance but the need for further experimental evidence is emphasized.
New estimates of dry matter intake of lactating beef cows grazing three pasture systems
Authors: Barlow R. , Ellis K. J. , McLennan D. J. , Costigan P. , Hirst P. H.
Published: March 2009

Estimates of dry matter intake reported by Barlow el al. in this journal in 1988 appeared low for grazing beef cows during early lactation. Further estimates for 144 crossbred and Hereford cows at Grafton, NSW, support the contention that the previous estimates for early lactation were biased downward. This appears to have been simply a scale effect as rankings of pastures and cow genotypes remained unchanged, although the magnitude of differences did alter.
Feeding value for finishing pigs of silage effluent with a high initial pH
Authors: Patterson D. C.
Published: March 2009

Silage effluents with pH values of 4·1, 4·7 and 5·1 (normal (N), high (H) and very high (VH), respectively) were treated with hydrochloric acid to bring the pH of each effluent to 40. The effluents were offered to finishing pigs in a randomized block experiment (November 1983 to February 1984 at the Agricultural Research Institute of Northern Ireland) with dietary treatments which comprised a control diet in which meal was given to a standard scale of feeding, or effluent diets N, H and VH, in which the effluent was substituted on a dry matter basis for 150g/kg of the standard scale of feeding. In a negative control diet, meal was offered at 850 g/kg of the control diet. Water or effluent as appropriate was given on the meal, and water was also available ad libitum. A total of 60 pigs was used with mean initial and final live weights (LW) of 37·1 and 86·4 kg, respectively.

Effluents H and VH had higher ammonia N: total N and lower amino acid N: total N and lactic acid contents than effluent N. The rates of LW gain, feed conversion ratios, backfat thicknesses and the proportions of lean and fat in the ham joint were similar for the control diet and effluent diets N and H, indicating a similar nutritive value for all three. Effluent diet VH gave a significantly (P < 0·01) reduced rate of LW gain and poorer feed conversion ratio than diets N and H. While diet VH was consumed reluctantly with widespread refusals (mean refusal 28 g DM/kg DM offered), the feed refusals together with the lower lysine and threonine contents of the effluent would not have produced the observed degree of deterioration in growth and feed conversion. Possible reasons for the lower nutritive value are undetectable wastage of feed or the presence of an antinutritional factor in effluent VHG, or a combination of both factors.
Effects of competition with weeds on the growth, development and yield of sorghum
Authors: Everaarts A. P.
Published: March 2009

In two field experiments in Suriname, competition between weeds and sorghum (Sorghum bicolor(L.) Moench) was studied in the rainy seasons of 1982 and 1983. The crop was kept either weed-free or without weed control for each of six different periods of time from planting. Observations made at the end of each period allowed an analysis to be made of the growth and development of a crop with and without weed control.

Due to the crop canopy structure and fertilizer placement near the row, weed growth was concentrated in the rows. Starting atc.20–30 days after planting, competition with weeds reduced ground-cover and leaf area index of the crop. Competition reduced growth rates, leading to lower yields. Plant population density was not affected, but competition reduced the number of leaves present. Stem length initially increased with competition in one season, but was retarded in another. Competition for nutrients was strong and was found as early as 15 days after planting. Nitrogen was the element most competed for initially. Competition for water occurred, but competition for light seemed unlikely. About 20 weed-free days after planting were necessary to avoid yield losses and around 30 weed-free days to attain negligible weed growth at harvest. Yield reduction was mainly due to a decrease in number of grains per panicle. Competition during floret establishment (c.30–40 days after planting) should be avoided.
The influence of spring nitrogen on yield, yield components and glucosinolate content of autumn-sown oilseed rape (Brassica napus)
Authors: Bilsborrow P. E. , Evans E. J. , Zhao F. J.
Published: March 2009

The response of low glucosinolate, low erucic acid (double low) cultivars of oilseed rape to spring nitrogen application was examined at Cockle Park, Northumberland in three successive seasons (1987–90). Seed yield and protein content increased in response to increasing nitrogen application. In each season over 85% of the maximum recorded yield was obtained with an application of 150 kg N/ha. In the absence of spring nitrogen, seed yield varied considerably over the three seasons. The variation in seed yield and protein content between 1987/88 and 1988/89 can partly be explained by differences in the availability of soil nitrogen in the different seasons. Seed glucosinolate concentration was significantly increased withnitrogen applications between 0 and 150 kg/ha. Increasing nitrogen beyond 150 kg/ha hadlittle or no effect on seed glucosinolate concentration. The results are examined with reference to the varying effects of increasing nitrogen application rates on seed glucosinolate concentrations reported previously.
Comparison of seasonal patterns of growth, voluntary feed intake and plasma hormone concentrations in young sambar deer (Cervus unicolor) and red deer (Cervus elaphus)
Authors: Semiadil G. , Barry T. N. , Muir P. D.
Published: March 2009

During 1991/93, young sambar (5 months old) and red deer (7 months old) were confined indoors in individual pens in New Zealand and fed a pelleted concentrate diet (12 MJ ME/kgDM; 2·9% N) ad libitum for 21 months. Seasonal patterns of voluntary feed intake (VF1), liveweight gain (LWG), scrotal circumference and plasma concentrations of prolactin (PRL), luteinizing hormone (LH), testosterone (T) and progesterone (P) were compared using five stags and three hinds of each species.

Red deer showed a strong pattern of seasonality, with high VFI and LWG in summer and low VF1 and LWG in winter and with peak plasma T and scrotal circumference in stags in early autumn. Compared with red deer, sambar showed weaker seasonal patterns of VFI and LWG, with maximum values in autumn and minimumvalues in spring. Over a complete 12-month cycle, sambar deer gained similar amounts of liveweight to red deer but consumed substantially less feed, thus demonstrating a more efficient conversion of feed tobodyweight. Metabolizable energy (ME) requirements for both maintenance and gain were substantially lower for sambar than for red deer. Scrotal circumference and plasma T values in sambar stags attained their highest values during late autumn, winter and spring, but with a lower magnitude than peak values for red stags. Plasma PRL concentrations were seasonal in both species, with highest values in summer and lowest values in winter. Rapid increase of plasma P was first detected in red hinds in autumn and sambar hinds in spring when they weighed 96 and 90 kg respectively, and were aged 17 and 14 months. Rapid increase of plasma T was first detected in red stags in early autumn and sambar stags in mid-autumn whenthey weighed 117 and 101 kg, and were aged 16 and 15 months respectively.

It was concluded that sambar deer had endogenous cycles of VFI, body growth and hormone secretion, which were of lesser amplitude and with different seasonality from those of red deer. Young sambar deer were more efficient feed converters than red deer, and attained sexual maturity at an earlier age and lower liveweight.
Pasture renovation: interactions of vegetation control with slug and insect infestations
Authors: Barker G. M.
Published: March 2009

In a field trial at Rukuhia, New Zealand, ryegrass (Lolium perenneL.) and white clover (Trifolium repensL.) seed was direct drilled into pasture (i) without herbicide suppression of the resident sward, (ii) with banded application of glyphosate or paraquat herbicide at drilling to remove 50% of the resident sward and (iii) after complete removal of the grass and weed components of the old sward with glyphosate or paraquat before drilling. These treatments were compared with the untreated old swards. Where the old sward was removed by herbicide before drilling, pests moved onto the drilled seedling rows, but, where herbicide was sprayed in bands over the drill rows, the pests remained in or moved into the residual bands of the old sward. Significant beneficial interactions between herbicide use and in-furrow applications of molluscicides and insecticides resulted in reductions in the numbers of pests on the seedling rows. The influence of vegetation control on the pest burden is discussed in the context of current pasture renovation practices.
Effects of cypermethrin + dimethoate and extracts of Piper guineense and Azadirachta indica on the pests and yield of cowpea, Vigna unguiculata
Authors: Ivbijaro M. F. , Bolaji O. O.
Published: March 2009

Field trials were conducted in 1988 at the University of Ibadan to determine the effects of cypermethrin + dimethoate (Sherpa Plus®), the oil extract from ripe seeds of Piper guineense Schum & Thonn and the aqueous extract of ripe seeds of Azadirachta indica A. Juss on the pests and yield of cowpea. Cypermethrin + dimethoate was consistently superior to all other treatments in substantially reducing the population densities of Megalurothrips sjostedti Trybom and of Maruca testulalis Geyer, which are serious pests on flowers and buds, and in reducing the densities of four pod-sucking bugs. Pest population densities were also reduced by foliar sprays with A. indica or P. guineense extracts.

Seed yield after treatment with cypermethrin + dimethoate was 0·99 t/ha, more than double the yield from other treatments. A marginal increase in seed yield compared with the control was achieved by foliar spraying with A. indica extract.
Effects of late-autumn fertilizer dressing on accumulation of photosynthates in tea (Camellia sinensis) and its contribution to spring tea quality
Authors: Shen Y. , Yang X. , Xie X.
Published: March 2009

Two-year-old tea bushes were given NPK fertilizer on 12 November 1986 and 14CO2 on 22–23 December 1986 and 9–10 January 1987. Late-autumn fertilizer dressing stimulated photosynthate accumulation in the whole bush, especially in overwintering leaves and roots. Large amounts of photosynthates in overwintering leaves provide the nutrition required for early spring budding. Lateautumn dressing also accelerated the transport of photosynthates from leaves to roots in winter, where photosynthates, with absorbed nitrogen, synthesized more animo acids, especially theanine and phenylalanine. The re-use of photosynthates stored in the roots of the dressed bushes during shoot growth the following spring was also facilitated by late-autumn dressing. The contents of amino acids and caffeine in the shoots of dressed bushes were much higher than those in the control, whereas the content of polyphenol was lower than in the control. The results indicate that late-autumn dressing improves the quality of spring green tea.
Effects of plant population density and rectangularity on the growth and yield of poppies (Papaver somniferum)
Authors: Chung B.
Published: March 2009

Growth, yield and incidence of lodging of poppies were studied in Tasmania at 10–200 plants/m2 and at nominal rectangularities (within-row: between-row spacing) ranging from 1:1 to 10:1. In 1983/84 and 1988/89, there were asymptotic relationships between plant population density and both total dry-matter production and total head (capsule plus seed) yield at maturity. In 1983/84, a season with above-average wind, the incidence of lodging increased as density increased to > 50 plants/m2; morphine concentration decreased as density increased to > 100 plants/m2. This resulted in parabolic relationships between yield of erect (machine-harvestable) heads and yield of morphine from erect heads with plant density, the maximum morphine yield from erect heads being achieved at 70 plants/m2. In 1988/89, a season with below-average wind, the effects of lodging were less severe at high densities and the components of ‘erect’ yield were adequately fitted by an asymptotic function. Rectangularity of 1:1 gave higher total dry matter production, total head yield, yield of erect heads and morphine yield from erect heads than 4:1 and 10:1. Since calm conditions similar to those of 1988/89 occur only once in every 4 years, growers should be encouraged to establish c. 70 plants/m2. As most commercial crops in Tasmania are drilled in 150–175 mm rows, growing at 70 plants/m2 to maximize the effect of plant density would also approximate to the ideal rectangularity (2:1 in this case).
Rumen fill, forage palatability and alimentary behaviour in sheep
Authors: Baumont R. , Seguier N. , Dulphy J. P.
Published: March 2009

Five sheep were fitted with rumen cannulas and fed once daily ad libitumat 09.00 h with a low-quality mixed-grass hay or a good-quality lucerne hay. The effects of a second amount of the same hay or of the second hay distributed at the end of the large meal following the morning distribution, when rumen fill reaches its daily maximum, were investigated for feed intake, alimentary behaviour and rumen fill. The second distribution induced a true meal (200–400 g dry matter intake), except in the case of mixed grass offered after lucerne. On the basis of initial eating rate and the amount ingested, the highest palatability was for lucerne offered after mixed grass, and the lowest for mixed grass offered after lucerne. Diet selection was more pronounced with lucerne than with mixed grass, as indicated by the larger decrease in the neutral detergent fibre content of the fraction ingested. The true meals following the second distribution were associated with an increase in rumen fill up to 10% of the daily maximum observed without the second distribution. However, rumen fill with lucerne remained 1 kg lower than with mixed-grass hay, even after a second meal. It is concluded that the sensory response induced by a distribution of a sufficiently palatable hay is able to override the satiety signals due to rumen fill, and that there is a permanent balance between the stimuli related to the characteristics of the food available and those related to reticulo-ruminal digesta.
Oviposition deterrence and ovicidal properties of some plant powders against Callosobruchus maculatus in stored cowpea (Vigna unguiculata) seeds
Authors: Ofuya T. I.
Published: March 2009

Powders made from 15 plant species were tested in the laboratory against C. maculatus on stored cowpea seeds. Fewest eggs were laid on seeds mixed with Nicotiana tabacum powder. Few eggs were also laid on seeds mixed with powders obtained from Erythrophleum suaveolens and Ocimum gratissimum. N. tabacum powder, followed by E. suaveolens powder, was the most effective in reducing egg hatch.
Storage root quality in sugarbeet in relation to nitrogen uptake
Authors: Pocock T. O. , Milford G. F. J. , Armstrong M. J.
Published: March 2009

The relationships between the amounts of nitrogen fertilizer applied and taken up by sugarbeet crops and the concentrations of sugar and α-amino-N in the storage root were examined using data obtained from fertilizer-response trials on different soils in the UK and Belgium between 1974 and 1985. On unmanured mineral soils, crop uptakes of N without fertilizer ranged from 65 to 190 kg/ha and increased linearly with the amount of fertilizer N applied. On organic soils or mineral soils that had received large applications of organic manure, crop uptakes of N were very large (295–383 kg/ha) and were not increased by applications of fertilizer N.

The amino-N contents of harvested beet increased with crop N uptake. The distributions of crop N to the storage root and of storage-root N to amino-N differed, especially in manured, diseased and drought-affected crops. Greater proportions of crop N were present in the storage roots of manured crops than in conventionally fertilized crops, and more of the storage-root N was present as amino-N in crops affected by virus yellows or drought than in healthy, unstressed crops.

The fresh weight concentrations of sugar in the storage root also differed between sites and years but were not consistently reduced by applications of fertilizer N at individual sites. However, when compared across sites, concentrations were negatively correlated with crop N uptakes and the amounts of N in storage roots. This was because particular crops grown on mineral soils with large applications of manure or on organic soils had large N uptakes and exceptionally low concentrations of sugar.

The physiological implications of these relationships between N uptake and amino-N and sugar accumulation are discussed.
Response of maize to copper and sulphur in tropical regions
Authors: Ojeniyil S. O. , Kayode G. O.
Published: March 2009

Field studies were conducted in order to determine the components of yield and response of maizeto soil applied copper and sulphur in the rainforest-savannah transition zone and Guinea savannah zone of Nigeria. Five CuO treatments, 0, 1, 3, 6 and 9 kg/ha, were applied to maize in 1988–90, and grain yield was consistently and significantly increased by the 1 kg/ha CuO treatment. Five S treatments, 0, 10, 20, 40 and 80 kg/ha, were applied to maize in 1989–90, and all treatments increased grain yield significantly in 1989, but only the 10 kg/ha S treatment increased grain yield significantly in 1990. Higher amounts of applied S increased leaf S significantly in the Guinea savannah zone.
Effects of modified circulating prolactin levels on seasonal wool growth in Romney ewes
Authors: McCloghry C. E. , Foldes A. , Rintoul A. J. , Maxwell C. A. , Hollis D. E. , Baker P. J. , Kennedy J. P. , Wynn P. C.
Published: March 2009

The study investigated the effects of chronic elevation or suppression of circulating prolactin levels on seasonal wool growth in Romney sheep. Ewes (n = 10/group) were housed indoors under natural lighting (latitude 34 °S) and received either 50 mg bromocriptine i.m./ewe/28 days (Group B), 1 mg spiperone s.c./ewe/day (Group S) or no treatment (Group C) commencing in summer. Wool growth and liveweight were measured every 4 weeks and venous blood samples were collected for prolactin determination. Plasma prolactin levels (mean±s.E.) in Group C exhibited a gradual seasonal decline from 121±29 ng/ml to 35±9 ng/ml. Bromocriptine suppressed prolactin levels rapidly from a pretreatment value of 118±2 ng/ml to below 12±7 ng/ml for the duration of the study. Prolactin levels in Group S were not significantly higher than Group C, with the exception of the first 14 days following the initial treatment. A seasonal reduction in wool growth of c. 25% was observed in all groups; however, no significant treatment effect was evident. Mean liveweight of all animals increased from 50·4±0·8 to 56·8±0·7 kg during the study. These results indicate that perturbation of the annual cyclic secretion of prolactin does not affect wool growth in the Romney ewe.
Effects of previous crop, sowing date, and winter and spring applications of nitrogen on the growth, nitrogen uptake and yield of winter wheat
Authors: Milford G. F. J. , Penny A. , Prew R. D. , Darby R. J. , Todd A. D.
Published: March 2009

Multifactorial experiments at Rothamsted Experimental Station in two contrasting seasons, 1985/86 and 1986/87, tested the effects of treatment combinations that varied the supply of nitrogen at important stages of crop development in autumn and spring on the grain yield and nitrogen content of September- and October-sown winter wheat. Treatments that altered the nitrogen supply in autumn were an application of winter fertilizer N and sowing the wheat after rape or oats, which left different amounts of residual N. These were combined with treatments which tested the effects of 200 kg N/ha in spring applied as early or late dressings and as single or divided dressings. The effect of applying an additional 50 kg N/ha in summer was also tested in 1985/86.

In both experiments, larger yields were obtained from sowing in September than in October. The September-sown wheat grew better over winter in 1986/87 than in 1985/86 but the early advantage in size and N uptake resulted in enhanced production of straw rather than grain. Residues of N from previous crops were smaller after oats than rape in both years. This difference in soil N did not affect the over-winter growth and N uptake of the October-sown wheats. Neither this difference in residual N nor an application of fertilizer N in winter affected the yield of the following September-sown wheat in 1985/86 because autumn growth and N uptake were restricted by adverse weather. In 1986/87, however, wheat that followed oats yielded 0·42 t/ha less grain than wheat that followed rape, and the deficit in yield was removed by an application of fertilizer N equivalent to the deficit in soil N.

Yields were decreased when the spring N was applied as a delayed, single dressing in April especially if the wheat was sown in September after oats, or was not given winter N. Yields were not affected by any of the other combinations of single v. divided dressings or early v. late applications of spring N, despite these being given at very different stages of apical development.

The percentage of N in the harvested grain was greatly increased by winter applications of fertilizer N, especially to wheat grown after oats, by applying the spring N as a late, single dressing and, in 1986, by applying N in summer.
Effects of cutting height on the productivity and composition of perennial ryegrass–white clover swards
Authors: Acuña G. H. P. , Wilman D.
Published: March 2009

All combinations of five cutting heights (2, 4, 6, 8 and 10 cm), two rates of P application (0 and 100 kg P/ha per year) and two irrigation treatments (0 and maximum soil water deficit 35 mm) were compared on field plots sown with a mixture of perennial ryegrass (Lolium perenne L.) and white clover (Trifolium repens L.) in Wales. The cutting and P treatments were applied for 4½ years (1986–90) and the irrigation treatments for 2 years (1987 and 1988). The plots were cut at 4-week intervals from April to October each year.

Applied P and irrigation had only a small effect on the productivity and composition of the swards. The proportion of white clover in the sward was inversely related to the height of cutting, so that clover was almost eliminated by 3 years of 10 cm cutting. This reduction in clover content led to a 50% reduction in herbage yield. Close cutting increased the tiller density of ryegrass in May and June of the first harvest year, but this effect was subsequently reversed as clover competed more strongly with ryegrass under close cutting. The proportion of unsown species, predominantly Agrostis tenuis, was much higher in the third and fourth than in the first and second harvest years and was positively related to the height of cutting. Close cutting depleted soil K and soil water.
Winter cover crops to minimize nitrate losses in intensive lettuce production
Authors: Jackson L. E. , Wyland L. J. , Stivers L. J.
Published: March 2009

A 2-year study conducted in Salinas, California in 1989–91 showed that soil nitrate (NO3–N) concentrations were reduced by cover crops during a short winter fallow period and that this practice can be compatible with year-round vegetable crop production schedules by planting and incorporating cover crops directly on the beds into which the lettuce crop will be direct seeded in the early spring. Cover crops grown the first year were oilseed radish (Raphanus sativus cv. Renova), white senf mustard (Brassica hirta cv. Martigena), white mustard (Brassica alba), Phacelia (Phacelia tanacetifolia cv. Phaci), rye (Secale cereale cv. Merced) and annual ryegrass (Lolium multiflorum). Only phacelia and Merced rye were included in the second year. In both years, all of the cover crops depleted soil NO3-N and soil moisture relative to the fallow control. Estimates of cover crop root length, based on core sampling to 60 cm soil depth, averaged 18800 m/m2 after 17 weeks of growth the first year and 12500 m/m2 after 13 weeks of growth the second year. Above-ground dry matter production averaged 449 g/m2 (12·8 g N/m2) the first year and 161 g/m2 (61 g N/m2) during a shorter growing period and under the more adverse growing conditions of the second year. Following cover crop incorporation with a rotary tiller, soil ammonium (NH4-N), N03-N and net mineralizable N (anaerobic incubation) peaked after c. 1 week, then gradually declined for 1 month. Cover-cropped plots sustained higher net mineralizable N levels than the fallow control after incorporation. Nitrate concentrations after spring rains were lower in soils left fallow during winter. The subsequent lettuce crop was not affected by cover crop treatment.
Whole body metabolism of cysteine and glutathione and their utilization in the skin of Romney sheep: consequences for wool growth
Authors: Lee J. , Harris P. M. , Sinclair B. R. , Treloar B. P.
Published: March 2009

Infusion of [35S]-labelled cysteine into the jugular of Romney sheep of different ages was used to estimate the extent of combined cysteine and cystine (cyst(e)ine) and glutathione (GSH) interchange in various tissues, including skin, and to measure whole body irreversible loss rates (1LR) for cyst(e)ine. The studies were undertaken at Palmerston North, New Zealand during 1990 and 1991.

Reverse phase HPLC using a fluorigenic reagent, 7-fluoro-2,1,3-benzoxadiazole-4-sulphonate (SBD-F) was used for the simultaneous determination of thiols (cysteine and GSH) in whole blood (bound and free fractions), liver, kidney, small intestine, muscle, pancreas and skin. The appearance of [35S]-label in thiol compounds and their oxidation products was determined by ion-exchange HPLC. Specific radioactivities (SRA) for cyst(e)ine and GSH derived from this data showed equivalence for cysteine and GSH SRAs in all tissues, except for whole blood, indicating rapid withintissue interconversion between these thiols. In whole blood, however, the very low SRA for GSH (< 4 DPM/nmol) compared to cyst(e)ine (250 DPM/nmol) indicated markedly slower or negligible exchange with red blood cell GSH, and hence little inter-organ transport of [35S]-label as GSH.

Close infusion of [35S] cysteine into a defined patch of skin and collection of the venous outflow permitted directin vivomeasurement of the proportional uptake of cysteine by the skin. Results indicated considerable variation in the uptake of cysteineper se(20–40%) but no, or very little, oxidation of cysteine in the skin and no net export of GSH.

The combination of whole body, tissue and skin specific studies of [35S]-labelled cysteine metabolism quantitatively confirmed the very high proportion of circulating cyst(e)ine in sheep which is directed to skin and wool protein synthesis alone, and highlighted those aspects of this metabolism which are of most importance to wool production.
Wool follicles initiate, develop and produce wool fibres in ovine fetal skin grafts
Authors: McCloghry C. E. , Hollis D. E. , Raphael K. A. , Marshall R. C. , Foldes A. , Kennedy J. P. , Wynn P. C.
Published: March 2009

Research into the mechanisms that control the initiation and development of wool follicles has been severely hampered by the inaccessibility of fetal skin in utero. The aims of this study were to determine whether ovine fetal skin, when grafted onto the athymic nude mouse (nu/nu), could be maintained outside the uterine environment and, if so, whether it would retain its ability to initiate and develop wool follicles capable of producing wool fibres.

Skin was removed from the mid-side region of ovine fetuses on days 45, 55, 65, 75, 85 and 95 of gestation, and transferred to graft beds prepared on anaesthetized nude mice. After developing for 20 days on the recipients, the grafts were excised for histological examination. Control ovine fetal skin was also obtained at the above times and from fetuses on days 105 and 115, and similarly processed for histological examination.

Fetal skin at all ages was successfully grafted onto nude mice; 90% of all grafts were accepted and maintained by the recipients. Follicle initiation and/or development occurred in all grafts, including those formed from day 45 fetal skin, collected and grafted prior to follicle initiation in vivo. The number of follicles in grafted skin was reduced compared to that in control fetal skin of equivalent age; however, follicle development was generally accelerated. Follicle initiation and development occurred predominantly in the peripheral zone of the grafts. Some of the follicles present in the skin at grafting were lost due to the grafting procedure, while others continued to develop and produce wool fibres. Follicle development varied considerably between grafts. All grafted skin exhibited premature loss of the periderm layer and cornification of the epidermis, probably in response to the exposure of the skin surface to the atmosphere. There was a notable absence of both arrector pili muscles and sweat glands associated with graft follicles, and a retardation of sebaceous gland development.

The grafting technique developed in this study has enabled ovine fetal skin to be maintained outside the uterine environment for extended periods of time and may provide an improved means for future investigation of wool follicle initiation and development.
Experiments with upland rice in southern Belize: fertilizer application, weed control, plant spacing, sowing rate and variety
Authors: Johnson D. E. , Lee P. G. , Wilman D.
Published: March 2009

Agronomic research was carried out on upland rice in Toledo District, Belize, in 1979–86, with the objective of improving returns from the traditional system of shifting cultivation and of examining the potential for reducing the demand for new land by cropping for more than one season. The rice was grown in the wet season on land cleared from forest by slash and burn, using a traditional planting technique, placing seed in holes made with a pointed stick.

In a series of fertilizer experiments, in which rice was grown for up to 7 consecutive years, urea and triple superphosphate both increased grain yield, whereas muriate of potash had no effect. Mean yield in the fifth year was 85 % of that in the first. Urea and triple superphosphate both increased the number of full grains/panicle.

A slash and mulch weed control treatment before sowing resulted in low yields of grain in the third year; yield after the use of propanil and 2,4-D (after sowing) was, on average, 77% of the yield after hand weeding; omitting weed control after sowing led to very low yields, particularly in the second and third years.

In the varieties Bluebonnet and C22, grain yield was increased by reducing the distance between stations, particularly where 6, rather than 15, seeds were sown per station. Reducing the distance between stations increased the leaf area index during crop development and the number of panicles/m2, which more than counterbalanced reductions in the number and area of leaf blades per plant, the number of panicles per plant and the number of full grains per panicle. However, the yield/kg of seed sown and per hour spent planting was greatest at the widest spacing. C22 produced more panicles per plant and a greater weight of grain per plant and per hectare than Bluebonnet.

It was concluded that returns from the traditional system can be improved and the demand for new land reduced.