bluuebunny/crossref_metadata_2025 huggingface dataset:
Yield estimation of tropical and temperate pasture species using an electronic capacitance meter
Authors: Jones R. J. , Haydock K. P.
Published: March 2009

Modifications to the New Zealand meter (Campbell, Phillips & O'Reilly, 1962) are briefly described and the results obtained with the modified meters presented.

Water was shown to have the dominant influence on meter reading—dessication of the plant material reduced readings, application of water increased readings.

The relation between yield of water (W) and meter reading (MR) depended on the circuitry of the meter used and was similar to that between capacitance change induced by a variable capacitor and meter reading. With the new meters this relation was strongly linear. For individual species the simple correlation of W on MR was generally superior to that for weight of dry matter. Regression coefficients for weight of water on meter reading differed between species and/or days but were correlated with the relative water content of the species (RW). Inclusion of RW in addition to that of W increased the variation accounted for (V%) when all species were included from 76·0 to 86·9%. However, the multiple regression did not eliminate bias. For individual species, there was no benefit in including the RW term.

The inclusion of height of herbage (H) in a multiple regression equation with weight of water greatly improved the V% when compared with the regression of meter reading on weight of water alone for oats dressed with three levels of nitrogen. The V% increased from 71·3% for W alone to 90·0% when W, H and H2 were included in the regression. Further testing using height of herbage over a wide range of species will be required to confirm this improvement for use in an overall regression.

Emphasis is placed on the very strong linear relation between yield (of water or dry matter) and meter reading within any one pasture at any one time. Use is made of this relation in the presentation of a new method, which overcomes the bias associated with prediction equations, for estimating pasture yields. This entails establishing the mean reading for any pasture and cutting for yield estimation three samples having such a mean. The limitations of the method for use with mixtures is discussed.
The utilization of dietary fats by ruminants:II. The effect of fatty acid chain length and unsaturation on digestibility
Authors: Andrews R. J. , Lewis D.
Published: March 2009

The effect of fatty acid chain length and unsaturation on digestibility in sheep were examined using partially purified samples of lauric, myristic, palmitic, stearic, oleic and linoleic acids. The digestibility of the fatty acids was relatively constant with only a very slight decrease on increasing chain length. There was an extensive hydrogenation of the unsaturated fatty acids.

The corrected digestibility coefficients for lauric acid was 91%, myristic 86%, palmitic 87% and stearic acid 81–83% whereas the corrected digestibility coefficients for oleic and linoleic acids were calculated at 87 and 93% respectively. The digestibility coefficients for the saturated fatty acids are higher than similar estimates that have been reported for non-ruminants. It is suggested that the ruminant is better able to utilize saturated fatty acids than the non-ruminant.
Digestibility of tropical pasture mixtures using the indicator technique
Authors: Olubajo F. O. , Oyenuga V. A.
Published: March 2009

Chromic oxide was used to assess the herbage intake of three tropical pastures mixtures namely: Cynodon plectostachyum and Centrosema pubescens (E); E plus Stylosanthes gracilis; Digitaria decumbens plus Centrosema pubescens and Stylosanthes gracilis, by-White Fulani (Zebu) steers and the use of faecal nitrogen to estimate digestibility of grazed herbage.

Chromic oxide recoveries in faecal organic matter ranged from 94·60% in treatment F to ca. 97·2 and 97·5% in treatments E and G respectively.

Positive relationships were found to exist between faecal organic matter nitrogen and herbage organic matter digestibility. Correlation coefficients of the ‘local’ regression equations obtained were positive but of low magnitude in some instances. Estimated mean organic matter intake was comparable to, but slightly lower than, the figures for animals of corresponding live weights in temperate countries while digestible organic matter intake was much lower.

The mean organic matter digestibility values were ca. 70·2 and 66·7% respectively for the two grazing seasons studied.
Buffalo sperm survival in glycine-yolk extenders
Authors: Yassen A. M. , El-Kamash M. A.
Published: March 2009

Survival of buffalo sperm in glycine-yolk extenders stored at 5°C was investigated. Eight glycine-yolk extenders containing variable levels of glycine (1·7 and 3·8%), glycerol (0 and 7%), fructose (0 and 1%) and 20% egg yolk, were compared with the conventional 4% glycine–50% egg yolk (control 1) and a 0·2 mol Tris-yolk extender (control 2). The highest rate of sperm survival in glycine extenders occurred in the one containing 1·7% glycine, 7% glycerol, 1% fructose and 20% egg yolk. All glycine extenders however, including control 1, were statistically (P < 0·01) inferior to the Tris-yolk. Sperm survival at the 4th day of storage for the glycine extenders ranged between 30 and 63% but it was 83% for the Tris-yolk.

Adjusting the pH of the glycine extender to 6·5 increased the percentage of sperm survival but it was still below that occurring in the Tris-yolk. Sperm survival in glycine yolk adjusted to pH values of 5·9, 6·5 and 7·1 were 55, 65 and 60% compared with 75% for the Tris-yolk control.
Changes in trace element composition of developing barley grain
Authors: Duffus Carol M. , Rosie Roberta
Published: March 2009

Changes in the amounts of the trace elements iron, zinc, manganese and copper, present in intact grain, endosperm, testa pericarp and embryo throughout the developmental period were recorded. Accumulation of iron and zinc in intact grain was extremely rapid, rising in the case of iron from 40 ng/grain to 1600 ng/grain between 5 and 40 days after anthesis. Manganese accumulated steadily throughout, reaching a final value of 475 ng/grain. Significant amounts of copper were present throughout and a small peak was observed at 38 days after anthesis. Some variation from this overall pattern was found in the different morphological parts as development proceeded. This was notable in the case of embryo manganese, which was undetectable until 45 days after anthesis, when levels rose dramatically to reach a steady maximum of around 100 ng/embryo. The results are discussed in relation to the biochemical events accompanying maturation.
Milk-fed calves: 2. The effect of length of milk feeding period and milk intake upon herbage intake and performance of grazing calves
Authors: Le Du Y. L. P. , Baker R. D. , Barker J. M.
Published: March 2009

Forty-eight Hereford × Friesian steer calves purchased at 7–10 days of age were reared on reconstituted milk substitute and groups of 12 were weaned at 86, 128, 170 or 212 days. Six calves at each weaning age were fed high (H) and low (L) quantities of milk normally associated with 240-day lactation yields of 2000 or 1000 kg. Calves were housed until day 63 of the experiment and then strip-grazed on swards of Loliun perenne with a daily allocation of herbage dry matter equivalent to 60 g/kg LW.

Herbage intake per unit live weight prior to weaning was consistently greater for the calves receiving low quantities of milk. Following weaning there was a rapid rise in herbage intake towards a maximum of 30 g OM/kg LW when sward conditions were non-limiting. The amount of milk fed prior to weaning affected herbage intake after weaning, and H groups did not achieve similar intakes to their L contemporaries until some weeks after weaning. The H groups grew faster from birth to weaning than the L groups but they experienced a more severe check in live-weight gain after weaning which nullified the advantage of better weight gains between the start of the grazing period and weaning. In consequence, there was no significant effect of the quantity of milk consumed prior to weaning upon live-weight gain during the grazing season. The results indicate a marked benefit from distributing a given quantity of milk over a longer feeding period as similar growth rates occurred for the H86 v. L128, H128 v. L170 and H170 v. L212 groups. Calves receiving milk consumed less herbage and spent a smaller proportion of the day grazing than weaned contemporaries, which suggests that metabolic rather than physical or behavioural factors are likely to limit their intake.
Effect of short-term water deprivation in summer on Marwari sheep
Authors: Ghosh P. K. , Khan M. S. , Abichandani R. K.
Published: March 2009

Effect of 24 h and 48 h of water deprivation on glomerular filtration rate (GFR), and on blood and urine electrolyte levels in Marwari sheep of the Rajasthan desert, India, have been recorded. Body weight, urine volume, GFR and erythrocyte sodium concentration in these animals registered considerable decreases due to dehydration. Both plasma sodium and urinary potassium concentrations remained unaffected. While plasma potassium was somewhat reduced, the potassium in red blood cells increased after 48 h of water deprivation. The most remarkable response was in the concentration of urinary sodium which rose to more than double the normal level.
A new record of root rot of broad bean (Vicia faba) from the Sudan
Authors: Ibrahim G. , Hussein M. M.
Published: March 2009

Fusarium solani f. sp. fabae Yu & Fang was isolated from root-rotted field bean (Vicia faba)plants at the Research Farm, Hudeiba Agricultural Research Station, Northern Province, Sudan. This is the first record of this fungus on field beans in the Sudan. Cultural and morphological characteristics of the fungus on potato-dextrose agar (PDA) and the symptoms caused are described.
Investigations on Nigerian root and tuber crops: effect of potassium on starch yields, HCN content and nutrient uptake of cassava cultivars (Manihot esculenta)
Authors: Obigbesan G. O.
Published: March 2009

Field experiments were made in the rainforest zone of Western Nigeria over three cropping seasons on the effects of potassium fertilizer of one local cassava cultivar 53101 and two improved cultivars 60506 and 60447 which wereF1hybrids of the former. The results showed that K-fertilizer increased the starch yields only slightly. Cultivar 60506 produced significantly higher starch yields (P< 0–01) than the local strain, 53101, while cultivar 60447 gave lower starch recovery than the local cultivar.

A definite influence of K application on the cyanide (HCN) content of the tuber roots could not be established. The peeled tubers of the improved cultivars contained much less cyanide than those of the local 53101 strain (P< 0–01). Potassium had the highest (0·72–1·28% dry weight basis) while phosphorus had the lowest concentration (0·06–0·12%) in the peeled tuber. Owing to its higher yielding capability the unfertilized 60506 removed larger amounts of potash (average 110·9 kg k20/ha) from the soil than unfertilized 53101 (average 82·2 kg k20/ha).
The effect of interval between harvests and nitrogen application on the proportion and digestibility of cell wall, cellulose, hemicellulose and lignin and on the proportion of lignified tissue in leaf cross-section in two perennial ryegrass varieties
Authors: Wilman D. , Daly M. , Koocheki A. , Lwoga A. B.
Published: March 2009

The effect of six intervals between harvests and two levels of N application on the proportion and digestibility of cell wall was studied in two perennial ryegrass (Lolium perenne) varieties in the first and second harvest years in a field experiment. In the oase of four of the six intervals between harvests the proportion and digestibility of cellulose, hemicellulose and lignin and the N content of cell wall were determined. Diets derived from three of the harvesting treatments were fed, at maintenance level, to sheep as a partial in vivo check on the in vitro procedures. The effect of six intervals between harvests and two levels of N application on the proportion of lignified tissue in leaf cross-section was determined in two varieties in the first harvest year.

Effects of interval between harvests and time of year on herbage digestibility were due to effects on both proportion and digestibility of cell wall, particularly the latter. Hemicellulose digestibility appeared to be rather more affected by interval between harvests and rather more closely associated with the proportion of lignin than was cellulose digestibihty. The proportion of cell wall was particularly low and its digestibility particularly high in April and early May.

The N in cell wall accounted for about 10% of total N in harvested herbage on all treatments. The ratio of cellulose to hemicellulose averaged 1:0·88 and hemicellulose was rather more digestible than cellulose. Cellulose and cell wall were less digestible in vitro than in vivo.

The application of N tended to reduce the proportion of cell wall and to increase its digestibility in leafy but not in stemmy crops.

Interval between harvests and N application had no effect on the proportion of lignified tissue in leaf cross-section.
The effect of interval between harvests and nitrogen application on initiation, emergence and longevity of leaves, longevity of tillers and dimensions and weights of leaves and ‘stems’ in Lolium
Authors: Wilman D. , Droushiotis D. , Mzamane Mary N. , Shim J. S.
Published: March 2009

The effects of six intervals between harvests and three levels of N application on the initiation, emergence and longevity of leaves and longevity of tillers of Italian ryegrass and on dimensions and weights of leaves of four ryegrass varieties were studied in the first harvest year in field experiments. Dimensions and weights of leaves and ‘stems’ of the four varieties were recorded on three dates in the second harvest year.

The number of leaf primordia on the shoot apex of young Italian ryegrass tillers was increased by N application and seemed to be increased by increasing the period of uninterrupted growth allowed to the parent tillers. The number of leaves which emerged on marked tillers during a 30-week period was approximately halved by increasing the interval between harvests from 3 to 10 weeks, but was not affected by N application. The number of leaves which died on marked tillers was at least doubled by increasing the interval between harvests from 3 to 5 weeks. The second and third leaves to emerge on a tiller had a longer potential life than the first leaf. Increasing the interval between harvests greatly increased the average age of the green leaves in the canopy at the time of harvest.

Length and width, but not thickness, of fully expanded green leaf blades were increased by both N application and increased interval between harvests. The effect of applied N in increasing leaf size appeared to be an important reason for the positive effect of N on yield, particularly with the longer intervals. The effect of N in increasing the number of tillers and leaves was important with the shorter intervals. Applied N reduced dry weight per unit volume of plant tissue and increased ‘stem’ length and increased weight and volume of herbage per unit volume of canopy. The area of exposed surface of ‘stem’ seemed too large to be ignored when considering the photosynthetic capacity of the canopy, particularly with the longer intervals.
Changes in soil pH and exchangeable calcium in two liming experiments on contrasting soils over 12 years
Authors: Bolton J.
Published: March 2009

Soils were analysed from two long-term liming experiments on a sandy-clay loam at Rothamsted and a loamy sand at Woburn. Plots given four levels of limestone factorially combined with phosphate and potassium fertilizers (with magnesium subplots in 1974) were cropped with beans, barley, potatoes and oats from 1963 to 1974.

The smallest limestone applications (5 t CaCO3/ha) increased soil pH the following year to values predicted by lime-requirement determinations using a standard advisory method. The larger limestone applications (10 and 20 t/ha) increased pH proportionally less. Soil pH decreased after the first year with 5 t/ha in both experiments but increased at the 20 t/ha rate for 6 years in the sandy-clay loam and for 3 years in the loamy sand before starting to decline.

Exchangeable calcium (soluble in N ammonium acetate) decreased at approximately linear rates in all plots of both experiments from the first year. Slopes of the regressions were smaller at low than at higher rates of liming, depending primarily on the average pH. Rates of CaCO3 losses from the surface 23 cm of soil ranged from 225 to 823 kg/ha per year at Rothamsted and from 307 to 852 kg/ha per year at Woburn.

Observed rates of Ca loss were compared with an empirical relationship suggested by Gasser (1973) between annual Ca losses and soil pH under average rainfall conditions and estimates based on a model system.
An evaluation of potential seed treatments to control Fusarium solani f.sp. phaseoli, the cause of foot and root rot of Phaseolus vulgaris
Authors: Russell P. E. , Mussa A. E. A.
Published: March 2009

Two systemic fungicides, benomyl and thiabendazole, were more active than the non-systemic fungicide Drazoxolon in inhibiting fungal growth in vitro. A similar pattern was obtained in glasshouse trials with benomyl and thiabendazole giving adequate protection at low concentrations while Drazoxolon was ineffective unless applied at 50% the commercial product concentration. A field trial using thiabendazole, Drazoxolon and a mixture of benomyl and thiram confirmed the glasshouse results.

Some phytotoxicity was noticed with high concentrations of both benomyl and thiabendazole, but satisfactory disease control was achieved using fungicide concentrations which did not induce phytotoxicity.
Effects of fertilizer N and number of years in tillage on the protein content of feeding barley straw (cv. Nessa) and on N uptake and recovery
Authors: Gately T. F.
Published: March 2009

The effects of six amounts (0, 17, 34, 51, 68 and 85 kg N/ha) of fertilizer N, applied at sowing time as calcium ammonium nitrate, on the crude protein (N × 6·25) content of barley straw sown as the first, second and fourth or later tillage crop after grazed pasture were studied over three seasons at a total of 126 sites. In addition total N uptake and apparent recovery of fertilizer N were calculated for each cropping sequence.

The mean crude protein content of the 126 sites was 4·1% without N, increasing to 4·8% with 85 kg N/ha. Maximum protein content with 85 kg N/ha ranged from 4·4% in 1971 to 5·4% in 1973. It was highest in the year which gave the lowest straw yields. Protein content was higher when the barley was sown as the first or second crop after pasture than when it was sown as the fourth or later crop. Incremental of fertilizer N gave only small increases or decreases in straw protein contents. Over all sites straw protein content amounted to about 36% of grain protein contents. There was a significant positive relationship between grain and straw protein contents.

Nitrogen uptake in the straw without fertilizer N was 19, 18 and 12 kg/ha in barley sown as the first, second and fourth or later tillage crop after grass. The total uptake of N in the grain and straw combined was 93, 102, 107, 109, 111 and 116 kg N from applications of 0, 17, 34, 51, 68 and 85 kg/ha of fertilizer N. The mean apparent recovery of fertilizer N in the straw varied from 12% with 17 kgN/ha to 8% with 85 kg N/ha.
Performance of yam (Dioscorea spp.) setts planted without water
Authors: Onwueme I. C.
Published: March 2009

Setts of Dioscorea alata and D. rotundata sprouted as rapidly in dry soil, dry sawdust, or dry shredded newsprint as in moist sawdust. Sprouting was slightly less rapid when the setts were kept on a laboratory shelf. Sprouting loci were smaller but more numerous in the dry-sprouted setts. Sprout buds produced during dry-sprouting remained relatively unelongated when compared with moist-sprouted setts, but setts wetted after dry-soil sprouting for 14 days produced a greater number of vines per sett.

When D. rotundatasetts obtained from 8-month stored tubers were subjected to alternating wetting and drying during sprouting, several sprouting loci developed into negatively geotropic, finger-like structures, rhizome-like in appearance but tuber-like in bulk.

The cultural implications of the results are discussed, and a scheme is proposed for pre-sprouting yam setts indoors before planting them in the field.
The importance of seed size in early growth of wild and domesticated cowpeas
Authors: Lush W. M. , Wien H. C.
Published: March 2009

Domesticated cowpeas (Vigna unguiculata(L.) Walp.) have larger seeds than their wild relatives. The effects of this increase in seed size on seedling emergence and growth were investigated. In shallow sowings, to 5 cm, seed size had no effect on emergence, but in deeper plantings ahigher proportion of the larger-seeded accessions emerged, and they emerged earlier than smaller-seeded accessions. The size of seedlings just after emergence was inversely related to depth of planting and directly related to seed size. The greater size of the seedlings of larger-seeded accessions was maintained until at least 40 days after sowing, despite the higher relative growth rates of smaller, wild seedlings. When compared at the same size there was no general difference in the growth rate of wild accessions and that of domesticates. During the evolution of domesticated cowpeas, large seeds have probably been advantageous because of their better emergence and establishment under agricultural conditions, and because of the greater size of plants arising from them.
Downward movement and transformation of phosphorus in soils after long-continued fertilizer application to coconut (Cocos nucifera)
Authors: Loganathan P. , Nalliah V.
Published: March 2009

Determinations of sodium bicarbonate (pH 8·5) extractable P made on profiles of a sandy loam soil 7 and 8 years after fertilizer application to coconut in the Dry zone of Sri Lanka showed that the downward movement of P from concentrated superphosphate was greater than from rock phosphate (saphos). The surface layers (0–15 cm) of soil given concentrated superphosphate had higher P values (60 and 89 mg/kg for the 8th and 9th year respectively) than those given rock phosphate (3 and 16·5 mg/kg). At 40 cm depth the concentrated superphosphate treatment had 6 and 30 mg P/kg but the rook phosphate treatment had almost zero P at and below 40 cm.

Phosphorus in the soil profile 8 years after fertilizer application was fractionated by the method of Chang & Jackson. Concentrated superphosphate treatment increased the Al-P and to a lesser degree Fe-P and Ca-P. Rock phosphate treatment increased the Ca-P and to a lesser extent Fe-P and Al-P. Phosphorus concentration in the 14th leaf was significantly correlated with Al-P, Fe-P and NaHCO3-P but not with Ca-P and organic P.

The significance of the findings to phosphorus fertilizer application to coconut is discussed.
The fate of acetyl groups and sugar components during the digestion of grass cell walls in sheep
Authors: Morris E. Jane , Bacon J. S. D.
Published: March 2009

The digestibilities of grass cell wall constituents determined in a digestion trial were compared with those obtained by suspending various isolated cell wall preparations in nylon bags in the rumen of a sheep. Particular attention was paid to acetyl groups and to individual sugars, which were determined in both cases by gas liquid chromatography.

For dried grass and hay in the digestion trial the cell wall constituents showed digestibilities decreasing in the following order: arabinose, galactose, glucose, xylose, acetyl, lignin.

For a leaf cell wall preparation derived from all cell types except mesophyll, the nylon bag technique allowed the same order of digestibilities; rhamnose and uronic acids were also measured and found to be rapidly digested. Mesophyll cell walls placed in nylon bags were more readily digested than non-mesophyll. All the sugars, and also acetyl groups, were digested to the same extent.

In a grass cell wall preparation isolated from sheep faeces, tested similarly, xylose and glucose were digested to the same extent, but acetyl groups were less digested.

Removal of acetyl groups, using sodium ethoxide, which left the sugar composition and lignin content unchanged, increased the digestibility particularly of the cell walls from faeces.

The results are discussed with reference to the relationship between cell wall composition and digestibility.
Studies on reproduction in prolific ewes. 3. The development in size and shape of the foetal skeleton
Authors: McDonald I. , Wenham G. , Robinson J. J.
Published: March 2009

Measurements of 21 bone lengths and breadths were made on radiographs of 215 foetuses of known gestational ages ranging from 50 to 145 days obtained from 80 Finnish Landrace x Dorset Horn ewes. Number of foetuses per ewe varied from 1 to 5, but the main statistical analyses were based on the 22 sets of twins, 34 of triplets and 11 of quadruplets. Equations were fitted to relate each of the linear measurements to foetal weight alone, to foetal age alone, to foetal age together with number of foetuses, and to foetal age together with foetal weight. It was found that there were significant differences between the twins, triplets, and quadruplets in the lengths their bones attained at any specified weight or at any specified age but not when both weight and age were fixed. The relationships to weight and age jointly were significantly closer than to either of them alone even after allowing for number of foetuses. The mathematical model that fitted best was a modified Gompertz equation of the form

where ywas the measured length, w was the number of days prior to expected parturition, w was foetal weight, wu was an estimate of the expected foetal weight at time u, and P, Q, R and Dwere fitted constants.
Promotion and synchronization of cereal grain germination by osmotic pretreatment with polyethylene glycol
Authors: Akalehiywot T. , Bewley J. D.
Published: March 2009

The effects of osmotic pretreatments were tested on the germination responses of oat and wheat grains. Temperature and duration of the pretreatment with polyethylene glycol (PEG) at two osmotic potentials (OP) were the experimental variables. The rate and synchronization of germination at 5–25 °C were significantly improved in both species by osmotic pretreatments compared with untreated controls. Maximum promotive effects were obtained after pretreatment periods of 6 and 4 days at – 10 bars at 5 and 10 °C respectively, and after 3 days at – 20 bars at 25 °C. Rapid and synchronized germination of seeds may be of advantage by minimizing their exposure to environmental hazards at early stages following imbibition and by allowing more favorable competition with other fast-germinating and growing species.
Lactation performance of ewes and the growth of lambs, in Awassi sheep, under two different suckling regimes
Authors: Guirgis R. A. , Kassem M. M. , Kazzal N. T. , Abdallah R. K.
Published: March 2009

The present study was carried out on 39 local Awassi ewes. After parturition, lambs were left to suckle their dams for the first month of age, after which they were separated into two suckling regimes, restricted and continuous.

The average milk yield of ewes in the continuous system was 155·7 kg during the lactation period of 167±6·1 days whereas that of the restricted system was 139·8 kg during a lactation period of 183 ± 5·7 days. However, differences were not significant. Significant differences (P < 0·01), in favour of the continuous system, occurred in the amount of milk suckled by lambs in the different suckling systems from the 8th week onwards till weaning. Measured hand milk showed no significant differences between the two regimes.

Averages of butter fat percentages were 5·63 and 6·69 in the continuous and restricted systems respectively. The total percentage suckled milk, regardless of suckling regime, was 36·7 ± 1·99; averages were 41·6 ± 0·89 and 31·7 ± 3·52 in the continuous and restricted systems respectively.

The averages of commercial milk production from the 9th week after lambing until the end of lactation were 45·9 and 61·7 kg in the continuous and restricted systems respectively (P < 0·01). Averages of butter fat quantities in the commercial milk yield were 3·25 and 5·03 kg in the continuous and restricted systems respectively (P < 0·01).

The weights of lambs in the two suckling regimes started to differ significantly from the 14th to the 46th week of age; lambs reared under the continuous system were 4 kg heavier at the yearling age than those of the restricted system.

It might be worth considering weaning and selling extra lambs at 3 months of age to make full use of the high growth rate encountered in this period. The breeder could also obtain 11·4 kg more milk from ewes from 9 to 17 weeks after lambing in the restricted system than those in the continuous one. It might be advisable to use the restricted system and wean the lambs at 12 weeks of age; the excess milk obtained will outweigh the extra gain in body weight of 1·52 kg encountered in the continuous system.
Interaction between maize and cowpea at various frequencies
Authors: Remison S. U.
Published: March 2009

Maize and cowpea were grown at various replacement ratios (100/0, 67/33, 50/50, 33/67 and 0/100) in field experiments. The experiments were carried out during the early growing seasons of 1977 and 1978 at Ibadan in the rainforest zone of Nigeria. A maize cultivar (FARZ 17) and three cowpea cultivars (Ife brown, New Era and TVu 4557) were used.

Maize sown alone gave a greater yield than all mixtures. The yield of New Era cowpea was no less when grown in mixture with maize than when grown alone; indeed when grown in a 50/50 mixture it was significantly greater.
Complete diets for dairy cows: comparisons of feeding to appetite with rationing according to milk yield
Authors: Greenhalgh J. F. D. , Reid G. W.
Published: March 2009

Two experiments were made, each with 35 autumn-calving cows fed on complete diets containing 40–70% hay and 60–30% concentrates. In both experiments, cows fed to appetite on a diet containing 11 MJ metabolizable energy/kg D.M. for weeks 7–24 of lactation ate about 20% more than cows rationed according to yield, but produced only about 3% more milk. The cows fed to appetite gained more in live weight, but lost their weight advantage during the subsequent grazing season.

In Expt 1, a further group of cows were fed to appetite on diets progressively reduced in metabolizable energy content from 11·0 to 9·2 MJ/kg. Dry-matter intake decreased by about 1·2 kg/day per 1 MJ reduction in energy content. The lower dry-matter and energy intakes of cows on this treatment did not significantly reduce their milk yield, but their response when turned out to grass suggested under-nutrition in late winter. In Expt 2, increasing the energy content of the diet in early lactation (weeks 7–12) and reducing it thereafter had no significant effect on milk yield.

Within each treatment group there were reasonably close relationships between energy intake and energy requirement. Nevertheless, it seems likely that the efficiency of feed utilization of cows fed on complete diets will be low unless intake is controlled by energy dilution.
Reduction of yield of Vicia faba by foliar fertilization during the seed-filling period
Authors: Witty J. F. , Roughley R. J. , Day J. M.
Published: March 2009

Vicia faba, in common with other grain legumes, rarely gives economic yield increases in response to soil application of nitrogenous fertilizer either before sowing or at flowering (McEwen, 1970a, b; Day, Roughley & Witty, 1979). The lack of response was attributed to poor uptake of the applied fertilizer particularly at flowering (Day et al. 1979). Garcia & Hanway (1976), however, increased the yield of soya beans from 3695 to 5225 kg/ha with foliar sprays containing N as urea, P, K and S applied during the seed-filling period. Day et al. (1979) using four foliar sprays of the same composition increased yield of V. faba by 361 kg/ha (8·6%) following the uptake of 15% of the 80 kg N/ha applied. However, Robertson, Hinson & Hammond (1977) reported no yield responses of soya beans with up to five foliar sprays of the same composition and noted that those containing ammonium polyphosphate and KNO3 caused leaf damage that significantly reduced yield.
The deposition of sulphur in rainwater in central Kenya
Authors: Bromfield A. R. , Debenham D. F. , Hancock I. R.
Published: March 2009

The deposition of S in rainwater was measured at ten locations in central Kenya, monthly for 1 year (1977–8). Amounts deposited ranged from 1·58 to 3·81 (mean 2·47) kg S/ha. Concentrations ranged from 0·10 to 0·17 (mean 0·12) mg S/l rainwater. The washout factor (w) was 200 and the vertical deposition velocity (Vg) for dry deposition was 0·31 cm/sec. Two locations were affected by local anthropogenic emissions. The agricultural significance of these results is briefly discussed.
Studies on reproduction in prolific ewes
Authors: Robinson J. J. , McDonald I. , Fraser C. , Gordon J. G.
Published: March 2009

Estimates of the energy contents of the foetuses, placentae, foetal fluids, empty uteri and maternal empty bodies at 88 and at 144 days of pregnancy were obtained from a comparative slaughter experiment on Finnish Landrace × Dorset Horn ewes. Over this period the mean daily intakes of metabolizable energy (ME) for ewes with twin, triplet or quadruplet foetuses were 11·2, 12·0 and 12·2 MJ respectively (low plane of feeding) or 14·4, 15·2 and 15·3 MJ (high plane of feeding), total numbers of ewes being 15, 23 and 7 respectively. The diet contained 8·2 MJ of ME and 153 g crude protein per kg dry matter. All six categories of ewe lost energy from maternal empty-body tissues between 88 and 144 days at mean daily rates of 2·7, 4·1 and 4·9 MJ (low plane) and 1·4, 2·7 and 3·6 MJ (high plane), according to litter size. Rates of energy deposition in the gravid uterus were 0·72, 0·93 and 1·07 MJ/day respectively, and were not affected by plane of nutrition. Estimates of heat production from these balance data were confirmed by direct measurements made on about half of the ewes.

Estimates of the gross efficiency of utilization for foetal growth of the combined energy from maternal tissue and from ME intake, after allowing for maternal main–tenance, were similar for each litter size but were 0·14 and 0·11 on the low and high planes of feeding respectively. Consideration of these together with other published observations suggested that efficiency of utilization of ME in pregnancy increases linearly with the ME concentration of the diet and at concentrations below 10 MJ/kg dry matter is less than the efficiency of utilization of energy derived from maternal tissue loss.
The influence of cultural factors and mildew on yield of winter barley
Authors: Bainbridge A. , Finney M. E. , Jenkyn J. F.
Published: March 2009

In experiments on winter barley in 1975–6 and 1977–8 early or late sowing, full or half seed rate, nitrogen applied in March or April and tridemorph spray applied in autumn, early spring and late spring were assessed factorially in all combinations for their effects on mildew development, crop growth and grain yield.

Date of sowing had the biggest effect on yield. Early-sown crops (24 September 1975, 6 October 1977) greatly out-yielded the late-sown; by 79·8% in the first year and 53·9% in the second. Late sowing (6 November 1975, 2 November 1977) approximately halved plant emergence. Although late-sown plants developed more tillers, more grains per ear and larger grain this failed to compensate for the thinner stand.

Sowing at half seed rate did not decrease yield when compared with the crop sown at the full seed rate on the same date. In contemporaneous crops extra tillering and larger ears generally compensated for fewer plants.

The effect of date of applying N was variable. April N gave the best yield in the early· and late-sown crops in 1975–6 and in the late-sown crop in 1977–8. However, in the early-sown crop in the second year March N was best. Number of ears was increased in early-sown crops by March N but date of N application had no influence on number of ears in late-sown crops or on the number of grains per ear in any crop.

The winter of 1975–6 was mild and mildew developed on both early· and late-sown crops throughout their growth.

Single tridemorph sprays applied in autumn (14 November) to the early-sown crop or winter (25 February) to the late-sown crop or early spring (9 April) to both crops gave significant yield increases of 6·3–7·6%. Applying two sprays, one in autumn or winter plus one in early spring gave an increase equal to the sum of each applied separately. A late spring spray (14 May) had no significant effect on yield. The 1977–8 winter was colder and although mildew was moderate on the early-sown crop in autumn it was almost absent from this experiment after winter. Spraying failed to increase yield significantly.
Direct drilling and ploughing: their effects on the distribution of extractable phosphorus and potassium, and of roots, in the upper horizons of two clay soils under winter wheat and spring barley
Authors: Drew M. C. , Saker L. R.
Published: March 2009

A study was made in the unusually dry 1975–6 season of the distribution of extractable phosphorus and potassium, and of roots, in the top soil in the second year of direct drilling on a Denchworth series clay (with winter wheat), and in the fourth consecutive year of direct drilling on an Evesham series clay (with spring barley). With both soils there were greater accumulations of phosphorus and potassium in the upper 5 cm with direct drilling compared with ploughing. In the Denchworth soil there were smaller concentrations of phosphorus at all depths below 5 cm with direct drilling and in the Evesham soil this depleted zone was located between 10 and 15 cm depth. There was little extractable phosphorus at depths below 20–30 cm.

Measurements of the overall change in concentration of extractable nutrients at each depth between the beginning and end of the season suggested that there may have been contrasting patterns of depletion with cultivation treatments. Depletion was greater between 2·5 and 5·0 cm with direct drilling, and for spring barley on Evesham soil this coincided with the zone in which roots were most abundant. For potassium, there was an increase in the concentration in the 0–2·5 cm zone, apparently due to potassium loss from the maturing crops. At harvest, the total depletion of phosphorus from all zones between 0 and 50 cm depth was appreciably less than data (Cannell & Graham, 1979) on the content of phosphorus in the crop per unit land area, indicating that release from non-extractable reserves in the soil had occurred.

Despite the exceptionally dry summer of 1976, crop growth and yield were not adversely affected by the tendency for extractable phosphorus and potassium, as well as roots, to concentrate in the upper layers where desiccation could occur most readily. Possible reasons for this, as well as factors that may contribute to the observed patterns of distribution of nutrients and roots, are discussed.
Further studies on the effects of plant density, spatial arrangement and time of harvest on yield and root size in carrots
Authors: Salter P. J. , Currah I. B. , Fellows Jane R.
Published: March 2009

Three experiments were carried out over a 2-year period to study the effect of plant density and spatial arrangement and the time of lifting on yield and root size of carrots. Plant density treatments ranged from 108 to 1553 plants/m2 and plant arrangement was varied by growing the plants in 1-, 2-, 3-, 4-, 5-, 10-, 18- and 36-row systems within a 152 cm bed; there were either two or three harvests in each experiment.

Total plant fresh weight, total root yield and mean root weight were not significantly affected by plant arrangement over the range studied, but they all progressively increased with later harvests. The asymptotic relationships between these yield variables and plant density were adequately described by the equation of Shinozaki & Kira (1956), the relationships being significantly different for each harvest.

Yields of canning-size roots (20–30 mm diameter) were influenced by time of harvest, plant density and the interactions between these two variables. The yield of canning-size roots increased with plant density to a maximum and then declined, the maximum yield being achieved at a higher density with later harvests. In two out of the three experiments there was no effect of spatial arrangement on canning root yields but in the third experiment there was a significant row system × density × harvest interaction.

The numbers of roots harvested per metre of row did not differ significantly between the ‘outer’ and ‘other’ rows for any row system treatment. The mean root weight, however, was consistently greater from the outer rows of systems with three or more rows and this ‘edge’ effect became larger with later harvests.

The results are discussed in relation to other published data and to carrot production. It is concluded that any of the tested row systems are equally satisfactory for carrot production and the choice can be based on such considerations as the availability of suitable harvesting equipment.
The interaction of drainage and the response of winter wheat to nitrogen fertilizers: some preliminary results
Authors: Armstrong A. C.
Published: March 2009

Previous studies have indicated that improved artificial drainage increases yields of winter wheat by as much as 1 t/ha (Armstrong 1978), and suggested that an important component of this improved yield was the more effective utilization of nitrogenous fertilizer. Further data to support this hypothesis are here presented from the longterm drainage economics experiment at the Drayton Experimental Husbandry Farm, Warwickshire, England (Trafford & Oliphant, 1977; Bee, Dennis & Marks, 1978; Armstrong, 1978). The soil of this site is a non-calcareous pelo-stagnogley of the Denchworth series, and the mean annual rainfall is 617 mm. Both the soil and the climate are typical of much of the English midlands. The results presented here are, however, restricted to a single site, and are consequently tentative.
A contribution to the study of the problem of low fertility among Merino ewes in South Africa
Authors: Hunter G. L.
Published: March 2009

During the 12 months from September 1955 to August 1956, the reproductive tracts and ovaries of 4094 adult Merino ewes, recovered from the municipal abattoir at Pietermaritzburg, were examined. The great majority of the ewes had been consigned to the abattoir from one of three regions, between which differences in the nutritional value of the natural vegetation at different times of the year are recognized. From observations of the occurrence in the ovaries of active corpora lutea, it appeared that in some areas, mating Merino ewes during autumn and early winter is likely to result in the greatest percentage of ewes conceiving and in the highest lambing percentages. There was a suggestion, however, that in the more arid karoo areas, the percentage of ewes ovulating, as well as the mean ovulation rate per ewe, may remain relatively constant throughout the year. It seems likely that the low fertility of ewes of this breed may be due partly to the practice of introducing the rams into the flock at a time of year (spring and summer) in which many of the ewes are anoestrous, a practice which is often adopted in South Africa in order to avoid the poor growth rates which are known to occur among young lambs as a result of the high temperatures and the internal parasite infestations that are comcommon in the summer months. A need, in different areas, for extensive experimental evidence of the most suitable season for mating, is indicated.

No evidence of nutritional effects on fertility, either within or between areas, was obtained, but it is suggested that a higher proportion of ewes in certain areas may be capable of lambing in autumn as a result of more effective selection for this trait in these areas. There is also evidence that lack of fertilization of ova and early embryonic death may contribute significantly to the breed's low fertility.

Corpora lutea were observed more frequently in the right ovary than in the left. In gravid uteri, a greater proportion of foetuses were found in the right horn and, in addition, significantly more ova apparently migrated from the left ovary to the right horn than from the right ovary to the left horn. The numbers are given of large (diameter > 4 mm.) and medium (diameter 2–4 mm.) follicles observed in the ovaries both of non-pregnant ewes and of ewes in different stages of pregnancy, these stages having been estimated from measurements of foetal crownrump lengths.
Visual judgements of quality in meat I. Assessments of the proportion of lean to fat in bacon from photographs of the cut side
Authors: Gatherum D. P. , Harrington G. , Pomeroy R. W.
Published: March 2009

1. Eight experienced judges used a 20-point scoring scale in different ways when assessing the ‘proportion of lean to fat’ from the same photographs of cut bacon sides presented in the same arrangements. The average score for the 220 judgements made during the experiment by a single judge, which represents his over-all level of scoring or ‘standard of judging’, ranged from 13·7 to 12·0. The standard deviation, a measure of the degree of discrimination attempted by the judge, ranged from 3·26 to 4·74.

2. The judges varied in their consistency of assessment or ‘repeatability’. The standard error for a single judge, measuring the extent of the variation of his scores within photographs, ranged from 0·89 to 1·99. The judges who attempted to discriminate most between photographs tended to be the least consistent in their judgements, although one judge was a notable exception to this trend.

3. The consistency of judgement tended to decrease from the good (high-scoring) rashers to the poor (low-scoring) rashers, but this effect was more marked for some judges than for others.

4. Some of the variation in the scores awarded to each photograph was due to alterations in the standard of judging from batch to batch. When this was allowed for, the standard errors were all reduced and ranged from 0·61 to 1·31. The judges tended to adjust their standards according to the average quality of the batch being assessed. This led to the variation among the average scores for the batches being less than it would have been had their standards remained constant.

5. Alterations in the standard of judging during the experiment affected the scores awarded to good (high-scoring) rashers rather less than those awarded to poor (low-scoring) ones.

6. The correlations between the individual judge's mean scores for the forty-four photographs and the over-all mean scores were very high. For seven judges, they ranged from 0·962 to 0·984, whereas for the eighth judge the correlation was 0·918. The lower correlation for this judge was due to two rashers with very thin fat being heavily marked down.

7. The correlations between the over-all mean scores and two different combinations of three objective measurements were both about 0·92; these measurements were therefore slightly less closely related to the over-all scores than were an individual judge's mean scores.

8. The possibility of making the experimental technique more realistic and of improving the precision of such visual judgements by providing photographic scales of reference are discussed.