bluuebunny/crossref_metadata_2025_split huggingface dataset:
The effects of season and age of stand on the nutritive value of heather (Calluna vulgaris, L. Hull) to sheep
Authors: Milne J. A. 
Published: March 2009

SUMMARYIn two experiments frozen heather (Calluna vulgaris, L. Hull), which contained 85–90% of the current season's shoots, was offeredad libitumto castrated male sheep. In one experiment, heather harvested in July, September, November and March was offered to six sheep per harvest, D.M. digestibility fell from 55.9% in July to 41.9% in March, with the greatest decline occurring after flower development in August. There were no significant changes with season in voluntary intakes, which were low, ranging from 29 to 39 g D.M./kg W0.75/day. Apart from the July harvest, intakes of digestible D.M. were insufficient to maintain the sheep. The apparent digestibility of N(14·3–42·2%) and plasma urea N values (5–6 mg/100 ml) were low and undigested N of dietary origin in the faeces was high (25–45%). Sheep offered the September, November and March harvests were in considerable negative apparent balances of N and it was calculated that the sheep were in a negative balance of truly digested N. In a second ex-periment, heather harvested in August from pioneer, building and mature stands was offered to six sheep per harvest. There were no significant differences between stands in voluntary intake and digestibility.
An effect of soil ingestion on the utilization of dietary copper by sheep
Authors: Suttle N. F. , Alloway B. J. , Thornton I. 
Published: March 2009

SUMMARYTo test the hypothesis that the ingestion of Mo-rich soils by ruminants might adversely affect Cu metabolism, four groups of initially hypocupraemic ewes were repleted with a Cu-supplemented diet either soil-free or containing 10% of one of three soils of low, medium and high Mo content. The three soils were equally effective in inhibiting the response in plasma Cu and probably reduced the availability of Cu by more than 50%. The ingestion of certain soils produced increases in urinary Mo and Zn concentrations, indicating that the Mo and Zn ingested in soil can be biologically available: however, these Cu antagonists were probably released in insufficient quantities to have contributed greatly to the observed interference with Cu metabolism. Soil ingestion may be involved in the aetiology of hypocuprosis in cattle and swayback in sheep, since it commonly constitutes 10% of the D.M. intake of animals grazing winter pasture.
Effect of variations in dietary protein and of supplements of cod-liver oil on energy digestion and microbial synthesis in the rumen of sheep fed hay and concentrates
Authors: Sutton J. D. , Smith R. H. , McAllan A. B. , Storry J. E. , Corse D. A. 
Published: March 2009

SUMMARYEstimates have been made of the amount of energy fermented and the amounts of microbial protein and total fatty acids synthesized in the rumen of sheep given various rations of hay and concentrates. The sheep had re-entrant cannulas in the proximal duodenum. The amount of protein synthesized was calculated from the flow of RNA-N at the duodenum. The change in the amount of total fatty acids between the food and the proximal duodenum was also measured.In Expt 1, six sheep were given a low-protein basal diet and the same diet supplemented with a vegetable protein concentrate with or without tannin treatment. Some 72% of the digestible energy was apparently digested in the rumen and an estimated 150–170 g microbial protein were synthesized per kg organic matter apparently digested in the rumen. Differences due to the dietary treatments in the amount of energy digested and the amount of microbial protein synthesized were small and non-significant.In Expt 2, the effect of a supplement of 20 g/day of cod-liver oil (CLO) on digestion of a mixed diet of hay and concentrates was examined in five sheep. Despite a marked fall in the ratio of acetic acid to propionic acid in the rumen volatile fatty acids when CLO was added, there were no clear differences in the amount of energy fermented in the rumen, which averaged 64% of the digestible energy, or in the efficiency of microbial protein synthesis, which averaged 200 g/kg organic matter apparently digested in the rumen. On the basal diet an increase of 6·7 g total fatty acid/day occurred in the stomach. This was presumably synthesized in the rumen. However when CLO was added to the diet, a decrease of 4·1 g total fatty acid/day was measured.
The growth responses to weather of simulated vegetative swards of a single genotype ofLolium perenne
Authors: Thomas Henry 
Published: March 2009

SUMMARYThe influence of ambient weather conditions on the regrowth and morphology of a perennial ryegrass sward, over the period May–October 1972, was assessed by following the performance in the field of a succession of vegetative, single genotype, simulated swards previously grown under standard conditions. Crop growth rates estimated from largely non-destructive measurements of growth components (leaf extension, leaf weight/length ratio, tillering rate and tiller density) agreed with, and were more precise than, rates determined from harvests; the components having the greatest influence on growth rate were leaf extension and leaf weight/length ratio. Leaf extension and appearance were closely dependent on temperature; leaf weight/length was only slightly affected by the weather. The growth rates of total above ground parts, especially of herbage above the cutting height, were largely determined by temperature and initial leaf-area index, and insensitive to insolation. At higher temperatures, a greater proportion of assimilates was partitioned into herbage growth.
The utilization of maize silage for intensive beef production: II. The effect of urea on silage fermentation and on the voluntary intake and performance of young cattle fed maize silage-based diets
Authors: Thomas C. , Wilson R. F. , Wilkins R. J. , Wilkinson J. M. 
Published: March 2009

SUMMARYMaize was cut at 22·6, 27·0 and 41·6% dry matter and ensiled in 4 kg quantities in polythene bags without additive or after the addition of urea at 0·5, 1·0, 1·5 and 2·0% of the crop dry-matter content. Silos were opened at intervals up to 96 days. Maize of 23·4% dry-matter content was ensiled in 10 t butyl rubber silos without additive or after the addition of urea at 1·0% or fishmeal at 4·0% of the crop dry-matter content.Silages from the polythene bag silos were all well preserved. pH values increased and total acid content fell with increasing maturity of the crop. Addition of urea had little effect on these values. Only with the most mature crop did ammonia content increase markedly with increasing level of urea addition. All silages from the butyl rubber silos were well preserved with low pH values and similar total acid contents.Silages from the butyl rubber silos were used to measure voluntary, intake live-weight gain and efficiency of utilization of young beef cattle. The diets fed were silage without nitrogen supplement or supplemented with urea or fishmeal, added at ensiling, at feeding or included in a concentrate feed. One third of the total dry-matter intake of all cattle was provided by a pelleted concentrate feed consisting of equal quantities of dried grass and rolled barley.The increase in nitrogen content brought about by the addition of urea or fishmeal did not affect total dry-matter or organic-matter intake but was associated with 25% increase in nitrogen consumed. Live-weight gain on all treatments with added nitrogen was 20% higher than for the unsupplemented silage. This improvement in growth rate was accompanied by significant increases in efficiency of utilization of dietary dry matter and organic matter but efficiency of nitrogen utilization was reduced. The results indicate that neither the source nor site of addition of supplementary nitrogen significantly affect live-weight gain, dry-matter intake, organic-matter intake or utilization of dry matter or organic matter. They also demonstrate that urea can be used effectively to provide supplementary nitrogen to young cattle fed a maize silage-based ration.
Emergence of seedlings from different depths following high temperature stress
Authors: Onwueme I. C. , Adegoroye S. A. 
Published: March 2009

SUMMARYSeeds of Amaranthus, melon, cowpea and tomato were planted in moist soil at 1, 4 or 7·5 cm depth and subjected to a heat stress of 45 °C for 10 h on the day of sowing (day 0), 1 day after sowing or 2 days after sowing. Seedling emergence was retarded by heat stress, the most drastic retardation being due to heat stress on day 1 for cowpea and tomato, day 2 for melon, and day 0 for Amaranthus. Emergence also decreased with increasing depth of sowing. The interaction of depth and heat stress was also significant in all cases, such that the delay in emergence due to heat stress tended to be greater with increasing depth of sowing. The agronomic significance of the results is discussed.
The exploitation of polyploidy in sugar-beet breeding
Authors: Hornsey K. G. 
Published: March 2009

SUMMARYTetraploid lines were produced from colchicine treatments of European multigerm diploid material, and seeded in polycross plots. The same lines were crossed with European multigerm diploids to give anisoploid varieties, and also used as pollinators of American male-sterile diploids to yield monogerm and multigerm triploid varieties. Bigerm triploids were obtained from male-sterile hybrids heterozygous for the monogerm character, using European multigerm O-types in the grandparental generation. Double-cross monogerm triploids were obtained by crossing male-sterile diploids with non-equivalent O-types to provide male-sterile hybrids, and pollinating these with outbred tetraploids.Results from 35 root-yield trials showed that the sugar yields of the anisoploids and triploids were similar to those of contemporary commercial varieties, but that outbred tetraploids were slightly, and inbred tetraploids considerably, less productive. Changes induced in characters other than root weight by chromosome-doubling of diploid material were sometimes important, but not consistent in magnitude or direction. It is suggested that these changes result from selection and random drift rather than the ploidy change.A seed-yield trial demonstrated advantages of using hybrid seed-parents for triploid seed production. Problems of seed quality are discussed with particular reference to triploid varieties.It is concluded that the main importance of multigerm anisoploid varieties was in their combination of good sugar yield with near-monogerm fruit clusters at a time when commercial monogerm varieties were deficient in yield; the chief value of triploidy lay in its application to the short-term improvement of genetic monogerm varieties. The development of monogerm anisoploids is considered unlikely; but some advantages of deriving monogerm triploid varieties from tetraploid seed-parents are indicated, and it is suggested that these may become increasingly important in the future.
Manipulation of rumen fermentation in sheep by increasing the rate of flow of water from the rumen
Authors: Harrison D. G. , Beever D. E. , Thomson D. J. , Osbourn D. F. 
Published: March 2009

SUMMARYThe effects of an altered rumen dilution rate (D) upon the molar proportions of volatile fatty acids (VFA) in rumen liquor, VFA production rate, microbial protein synthesis and carbohydrate digestion within the rumen were studied using adult wether sheep.Dilution rate and VFA proportions were unaltered by the infusion of up to 121 water/day into the rumen of sheep fed dried grass and concentrate (9:1). There was a small but significant (P< 0·05) increase in the rumen volume when the infusion rate was increased from 8 to 12 1/day.The intraruminal infusion of artificial saliva (41/day), or artificial saliva containing 4% or 8% w/v polyethylene glycol (PEG) caused a significant increase in D with an associated decline in the molar proportion of propionate (Pr) in the rumen liquor. A similar effect was obtained with the intraruminal infusion of 2·5% w/v sodium bicarbonate. The overall regression of Pr on D was highly significant: Pr = 32·5–82·1D;r= –0·99, P < 0·001.A diet of flaked maize: dried grass (6:4) was offered to three sheep each fitted with a rumen cannula and with a re-entrant cannula at the proximal duodenum. The intraruminal infusion (4 1/day) of artificial saliva containing 4% w/v PEG caused a significant (P< 0·01) increase in D and a significant (P< 0·01) depression in Pr in two animals. The dilution rate and Pr in the third animal were virtually unaltered by infusion. The regression of Pr on D for the three animals was highly significant: Pr = 34·8–136·8D; r = –0·98, P < 0·001. Each increase in D was associated with an increased flow of α-linked glucose polymer, total amino acids and total microbial amino acids into the small intestine and with an increased efficiency of microbial protein synthesis within the rumen.
Variability in number of pods and yield in commercial crops of vining peas (Pisum sativumL.)
Authors: Hardwick R. C. , Andrews D. J. , Hole C. C. , Salter P. J. 
Published: March 2009

SUMMARYData were collected from 218 commercial crops of vining peas (Pisum sativumcv. Dark Skinned Perfection) to test the hypothesis that variability between commercial crops in the yield of vining peas is associated with variation in the number of pods per plant. Yield varied widely between crops; the coefficient of variation of crop yield adjusted to tenderometer reading 105 was 25%. Only a small part of this variation could be accounted for by the correlation between yield and the estimated number of pods per plant (r= 0·067, 216 D.F.), and significance levels were not substantially improved by allowing for the effects of sowing date and plant density, or by using data on number of pods at each separate node in place of the overall totals per plant. Consequently the hypothesis stated above is not supported and it is suggested that variation in the weight of peas per pod was the main cause of variation in yield between crops.A number of significant relationships were noted in the correlation analyses; (1) the mean number of pods per node at adjacent nodes tended to be positively correlated; (2) the number of pods per node at the first podding node tended to be positively correlated with plant density; (3) the numbers at the upper nodes tended to be negatively correlated with sowing date and with harvest date.
A study on the salt and sodium tolerance of rice
Authors: Bajwa M. S. 
Published: March 2009

SUMMARYAlthough salt injury in plants is due to both osmotic and specific ion effects, little is known about the reaction of rice plants to salinity under increasing sodium adsorption ratios (SAR) in the growth medium. Therefore, a glasshouse experiment was conducted to study the effect of four levels of salt concentration (20, 40, 60 and 80 m-equiv/1 with respect to the sum of Na+, Ca2+ and Mg2+) and four levels of SAR (2, 25, 50 and 75) on growth and mineral composition of rice cvs IR 2153-26-3 and IR 26. The results show that as salt concentration increased, dry-matter yield and percentage water content of shoots decreased regardless of the variety. The rate of decline with salinity was most pronounced under low SAR and in the salt-sensitive variety IR 26. With increase in SAR, the yield, percentage water content and concentrations of Ca, Mg, and K in shoots and roots decreased, but the effects were more marked at the lowest salt concentration and in IR 26. Variety IR 2153-26-3 showed greater tolerance, maintaining a higher concentration of Ca and higher Ca/Na and K/Na ratios and a lower concentration of Na and Cl in the tops compared with IR 26.The degree of salt injury in rice seems to depend not only on salt concentration but also on SAR in the growth medium whilst salt tolerance is associated with tolerance for both high salt concentration and high SAR. Therefore, in studies on screening rice varieties for salt and sodium tolerance, the interactive effects of SAR and salinity must be considered so as to ensure greater adaptability by the varieties recommended for salt-affected soils.
Symbiotic nitrogen fixation efficiency of mutant strains of lentil (Lens esculenta)Rhizobiumgrowing from pH 4·5 to 7·5
Authors: Rai R. , Prasad V. , Prasad T. N. , Kumar S. B. , Srivastava B. S. 
Published: March 2009

SUMMARYA strain ofRhizobiumisolated from the root nodule of lentil was caused to produce mutants and screened on a medium of pH 4·5. Five mutant colonies ofRhizobiumwere isolated from lentil which differed in growth over a pH range 4·5–7·5. Strains differed in their growth in acidic and calcareous soils and also in their effectiveness of N fixation.
Protein synthesis in muscle of mature sheep
Authors: Bryant D. T. W. , Smith R. W. 
Published: March 2009

SUMMARYProtein synthesis was measured in wether sheep by constant intravenous infusion of [3H]tyrosine. The specific radioactivity of plasma tyrosine at plateau was used to calculate tyrosine flux and the rate of protein synthesis in the whole body was estimated. For wethers fed hay and concentrates tyrosine flux was 2·46 mmol/h and protein synthesized was 5·29 g/kg body weight per day. Corresponding values for wethers fed barley straw were 30–35% lower.Fractional rates of protein synthesis in individual muscles were between 2 and 3% per day for diaphragm, longissimus dorsi, gastrocnemius, semitendinosus and vastus lateralis muscles from wethers fed hay and concentrates, but the value for vastus intermedius was higher. Corresponding rates for wethers fed barley straw were 18–36% lower.
Changes in yield, protein, oil and maturity of groundnut cultivars with the application of sulphur fertilizers and fungicides
Authors: Laurence R. C. N. , Gibbons R. W. , Young C. T. 
Published: March 2009

SummaryFungicide applications in Malawi have shown improvements in groundnut kernel yield. Improved fertility of sulphur-deficient soils contributes to such gains when sulphur dust is used as the fungicidal agent. Application of sulphur alone to deficient soils lowered the oil/protein ratio of kernels, whereas a singular fungicidal effect raised the oil content, probably through delayed plant maturity.
Nutritional evaluation of kale (Brassica oleracea) diets:4. Responses to supplementation with synthetic S-methyl-L-cysteine sulphoxide (SMCO)
Authors: Barry T. N. , Manley T. R. , Millar K. R. 
Published: March 2009

SUMMARYSynthetic SMCO was added to basal diets of either fresh kale or lucerne at the concentrations 0, 0·2, 0·4, 0·8 and 1·6% D.M. and each diet offered ad libitum to groups of four lambs that were individually fed indoors. Within each group, two lambs were of haemoglobin genotype AA and two were AB. Initial live weight (W) was 21 kg and the experiment lasted for 6 weeks.SMCO supplementation depressed voluntary intake, body growth and wool growth, caused the development of haemolytic anaemia and produced kidney hypertrophy. Effects were much more severe when SMCO was added to a kale than to a lucerne diet, with the lowest SMCO intake of kale-fed lambs (0·3 g/kg W) producing marked detrimental effects whereas the highest SMCO intake of lucerne-fed lambs (0·7 g/kg W) produced only small and transient effects. The intake depressions were evident during the first week of SMCO supplementation and persisted throughout the full 6-week feeding period. Approximately 80 and 65% of the changes in body growth and wool growth could be accounted for by changes in intake, and it was concluded that the most important effect of SMCO in ruminant diets is as an intake depressant.It is suggested that the greater ratio of soluble to structural carbohydrate in kale (2·3) compared with lucerne (0·9) probably resulted in a microbial population developing in the rumen of kale-fed sheep that could metabolize SMCO to dimethyl disulphide at a faster rate than occurred in the rumen of lucerne-fed sheep. Dimethyl disulphide production is postulated as the cause of both the haemolytic anaemia and appetite depression. Plasma SMCO concentrations did not increase with increasing SMCO intake in sheep fed either diet, indicating that there must have been negligible absorption of this amino acid from tho digestive system.No haemoglobin C was produced by any of the lambs fed lucerne, and kale-fed lambs produced significant amounts only during weeks 5 and 6, with type AA lambs producing more than type AB lambs. However, there was no difference between AA and AB lambs in rate of decline in total haemoglobin concentration or upon voluntary intake, body growth and wool growth.
Seasonal variation in some characteristics of ejaculated spermatozoa of Sudan Desert sheep in the tropics
Authors: Galil K. A. A. , Galil A. K. A. 
Published: March 2009

SUMMARYThe Sudan Desert sheep are well adapted to the hot tropical climate, are thirst tolerant and can travel for long distances under nomadic conditions in search of water and pasturage. The ejaculate volume, sperm cell concentration, total number of sperms per ejaculate, motility, percentage live and percentage abnormal spermatozoa and the fructolytic index of semen were estimated throughout the hot dry summer (March-June), hot rainy season (July-October) and the winter (November-February). The semen characteristics were normal for about 7 months (May-November) covering the last 2 months in summer, the whole rainy season and the 1st month in winter and deteriorated slightly during the rest of the winter and early summer. Thus the Sudan Desert rams appear to be able to breed throughout the year and their spermatogenesis is not seriously affected by high environmental temperatures.
The effect of seed treatment and seed covering medium on the establishment of crisp lettuce
Authors: Wurr D. C. E. , Fellows Jane R. , Gray D. 
Published: March 2009

SUMMARYThree experiments examined the effects on seedling emergence and seedling weight of covering pelleted, natural and pre-germinated seeds of the variety Pennlake with soil and other media.Covering seeds with a peat-vermiculite mix gave significantly greater, earlier and more uniform emergence and seedlings with a lower coefficient of variation (c.v.) of weight than covering with soil.Seedlings from pre-germinated seeds emerged more rapidly than those from natural and pelleted seeds and tended to be heavier when harvested 24 or 41 days after emergence. However, natural seeds consistently gave more uniform emergence than the other seed treatments and the lowest c.v. of seedling weight.
Validation of intake estimates in grazing beef cattle
Authors: Moir K. W. , Ebersohn J. P. , Evans J. 
Published: March 2009

SUMMARYGrowing beef cattle grazed six pasture types (all-grass or grass-legume mixtures) for 4 months on each. Live weight (mean of ten animals) and dietary energy concentration were measured at 2- or 3-weekly intervals. Values for feed intake estimated by back-calculating from feeding standards were on average 2·5% higher (range, 10% less to 12 % higher) than intake values estimated directly from dietary energy concentration and live weight. In contrast to this level of agreement of means, differences between methods within pastures were so large as to suggest the presence of overriding effects on predictors of voluntary intake. It was concluded that until these overriding effects are explained, there are no means of validating measured intakes in grazing cattle, or of accurately predicting the amount of beef produced from pasture.