bluuebunny/crossref_metadata_2025_split huggingface dataset:
Some effects of chloral hydrate on rumen fermentation and digestion in sheep
Authors: Mathers J. C. , Miller E. L. 
Published: March 2009

SUMMARYTwo experiments were carried out with adult sheep to investigate the effects of chloral hydrate (CH) on rumen metabolism and on the sites and extent of digestion.Experiment 1 confirmed that CH is a very potent methane inhibitor; doses of 1 or 4 g/day reduced methane production to 4% of that observed in the absence of the drug. In both experiments, CH administration altered the proportions of volatile fatty acids in rumen fluid. The main changes were an increase in propionic acid and a decrease in acetic acid with smaller increases in the proportion of isovaleric, valeric and caproic acids. Stoichiometric calculations indicated that only 21% of the hydrogen saved by prevention of methanogenesis was diverted to the synthesis of additional propionic and butyric acids and the fate of the remaining hydrogen was not determined unequivocally.CH had little effect on the extent of biohydrogenation in the rumen of the long-chain fatty acids in dried grass.The apparent digestibility of ether extract was reduced (P< 0·05) by CH but those of other proximate constituents and energy were little affected. There were no s gnificant effects of CH on the extent of digestion of dry matter, organic matter, non-ammonia nitrogen or ash between the mouth and abomasum, abomasum and terminal ileum or ileum and anus.
Lodging studies inLolium perennegrown for seed: 1. Seed yield and seed yield components
Authors: Hebblethwaite P. D. , Burbidge A. , Wright D. 
Published: March 2009

SummaryThe effects of lodging on the seed yield of S. 23 and S. 24 perennial ryegrass were investigated in a series of field experiments from 1973 to 1976. Natural lodging severely reduced seed yield in all years as a result of a decrease in the number of seeds per unit area. Controlled lodging at different stages of crop growth produced more variable results, indicating that lodging may affect both pollination and seed development. Disturbance of the crop during anthesis in order to aid pollination did not improve seed yields, possibly as a result of damage incurred.
Some effects of potassium chlorate administration onin vitroandin vivorumen fermentation
Authors: Barry T. N. , Harte F. J. , Perry B. N. , Armstrong D. G. 
Published: March 2009

SummaryHay was fed to anin vitrocontinuous culture of the rumen microbial population and to sheep kept in metabolism cages, and the effects of potassium chlorate addition on the rumen fermentation were studied. The compound was given for 8 daysin vitroand for either 3 or 8 daysin vivo.Potassium chlorate additionin vitro(13·7 mg/g hay D.M.) depressed the production of CH4and acetate, had little effect on propionate production and caused a small increase in the production ofn-butyrate andn-valerate. The treatment also depressed cellulose digestion and the concentration of DNA in fermentor liquor, but increased the CO2:CH4ratio in fermentor gas.When givenin vivofor 8 days at 6·7 mg/g hay D.M., potassium chlorate progressively depressed total VFA concentration in rumen fluid, had no effect on VFA molar proportions but caused a small increase in the CO2:CH4ratio in rumen gas. When administeredin vivofor 3 days at 14·4–15·3 mg/g hay D.M. the treatment increased the molar proportions of propionate and depressed those of acetate in rumen fluid without affecting total VFA concentration. There were considerable differences between animals in propionate response, and the maximum responses were generally obtained 2–5 days after dosing had ceased. Potassium chlorate addition also caused a temporary reduction in appetite with some sheep.It was concluded that potassium chlorate was toxic to the rumen microbial population when given for 8 days, but that large doses given over 3 days could be used to increase the ratio of propionic acid relative to acetic and butyric acids produced from the rumen fermentation.
The effects of moisture, propionic acid, sodium hydroxide and anaerobiasis on the stability of vitamin E in stored barley
Authors: Rice D. A. , Blanchflower W. J. , McMurray C. H. 
Published: March 2009

SUMMARYTwo experiments were designed to measure the effect of current barley storage systems on vitamin E stability.Whereas propionic acid and sodium hydroxide treatment of moist barley results in destruction of vitamin E, neither moisture per se nor anaerobic storage has such a detrimental effect. The destruction is most severe and rapid with alkali treatment, the reaction having substantially reached completion by 5 days. All the vitamin E isomers were affected to varying degrees, the order of susceptibility to decay being α-tocopherol > γ-tocopherol > α-tocotrienol > γ-tocotrienol.Possible explanations are given as to why the findings incriminating propionic acid in vitamin E destruction are at variance with currently held opinion.
The effect of variation in phosphorus intake on salivary phosphorus secretion, net intestinal phosphorus absorption and faecal endogenous phosphorus excretion in sheep
Authors: Scott D. , Whitelaw F. G. , Buchan W. , Bruce L. A. 
Published: March 2009

SUMMARYMature sheep fitted with rumen and duodenal cannulae, and fed a pelleted hay diet, were given supplementary phosphorus by continuous infusion into the rumen and the effects on salivary phosphorus secretion, net intestinal phosphorus absorption and faecal endogenous phosphorus excretion were studied. In control periods little phosphorus was excreted in the urine and little increase was seen in response to supplementation, the faeces being the major pathway for excretion. Increasing phosphorus intake led to an increase in net intestinal phosphorus absorption, a rise in plasma phosphate concentration, an increase in salivary phosphorus secretion and an increase in faecal endogenous phosphorus excretion. Overall net intestinal absorptive efficiency for phosphorus did, however, decrease as intake rose so that changes in faecal endogenous phosphorus excretion were in part due to increased salivary phosphorus secretion and in part to a reduction in overall absorptive efficiency. The significance of these changes in relation to the control of phosphorus balance in ruminants is discussed.
Number of kernels in wheat crops and the influence of solar radiation and temperature
Authors: Fischer R. A. 
Published: March 2009

SUMMARYThe number of kernels per m2 (K) in well managed and watered wheat crops was studied using results of experiments in Mexico and Australia in which short spring wheat cultivars were subjected to independent variation in radiation, largely via artificial shading, and in temperature. Also crops subjected to differences in weather (year), sowing date and location within Mexico, revealed responses to the natural and simultaneous variation which occurs in radiation and temperature. Responses in K were interpreted in terms of spike dry weight at anthesis (g/m2) and number of kernels per unit of spike weight.K was linearly and most closely related to incident solar radiation in the 30 days or so preceding anthesis, herein termed the spike growth period; for the cultivar Yecora 70 with full ground cover the slope was 19 kernels/MJ. This response seemed largely due to a linear response of crop growth rate to intercepted solar radiation. The proportion of dry weight increase partitioned to the spike increased somewhat with reduced radiation. Also increasing temperature in the range 14–22 °C during this period reduced K (slope approximately 4% per CC at 15 °C). The cause appeared to be lower spike dry weight due to accelerated development. The number of kernels per unit spike weight at anthesis was little affected by radiation or temperature, and averaged 78±2/g for the cultivar Yecora 70.With natural variation in radiation and temperature, K was closely and linearly correlated with the ratio of mean daily incident or intercepted radiation to mean temperature above 4·5 °C in the 30 days preceding anthesis. As this ratio, termed the photothermal quotient, increased from 0·5 to 2·0 MJ/m2/day/degree, K increased from 70 to 196 × 102/m2. These responses of K to weather, sowing date and location were closely associated with variation in spike dry weight.It was concluded that the ratio of solar radiation to temperature could be very useful for estimating K in wheat crop models. Also the analysis of K determination in terms of spike dry weight appeared promising, and suggests that wheat physiologists should place greater emphasis on the growth period immediately before anthesis.
Characterization of climatic factors affecting chilling injury in field-grown ratoon cotton
Authors: Sachs M. H. , Zilkah S. 
Published: March 2009

text abstractThe response of cotton (Gossypium hirsutum L.) to chilling temperatures has been documented mainly for germinating seeds and young seedlings (Christiansen, 1963; Christiansen & St John, 1981; Guinn, 1971; Sellschop & Salmon, 1928). Ratoon (known also as stub or biennial) cotton offers an opportunity to study the chilling injury of mature plants under field conditions. Observations showed that ratooning plants suffer stand loss during the winter. However, the surviving plants recover and start growing vigorously when temperatures rise, early in the following spring (Ellern, 1966; Evenson, 1970; McClintic, 1981).
The availability of copper to grazing ruminants in parts of North Yorkshire
Authors: Givens D. I. , Hopkins J. R. 
Published: March 2009

SummaryA total of 225 herbage samples were taken from two areas with a history of bovine hypocupraemia and examined for their Cu, Mo, total S, Zn, Fe and Cd content.In general, the concentrations of Cu and Mo (mean values 10·4 and 1·6 mg/kgD.M. respectively) were normal, as were those of Zn, Fe and Cd (mean values 43, 255 and 0–59 mg/kg D.M. respectively). The total S concentrations (mean value 3·5 g/kg D.M.) were, however, higher than found by some other workers.The concentrations of available herbage Cu were calculated using the following relationship of Suttle & McLauchlan (1976):logTA Cu = –0·0019 Mo–0·0755 S–0·0131 Mo × S–1·153,where TA Cu is the true availability of Cu, and Mo and total sulphur (S) are dietary concentrations as mg/kg D.M. and g/kg D.M. respectively. Animal requirements for available Cu were derived from estimates of the factorial Cu requirements of various classes of livestock, and when these were compared with the calculated concentrations of available Cu in the herbage they provided a possible explanation for the widespread hypocupraemia experienced in these areas.
Storage stability of DDT/Lindane emulsifiable concentrates and reworking deteriorated stocks
Authors: El Attal Z. M. , Moustafa Omayma K. , Said A. A. A. 
Published: March 2009

SummaryInvestigations of the reasons for the instability of emulsifiable concentrates (ECs) during storage and a study of reprocessing insecticide ECMs whose emulsification propertieshad deteriorated during storage is reported. Bioassay showed that very stable emulsions, although physically perfect, leave inadequate residues on the treated leaves. When a deteriorated EC was reprocessed, its emulsification properties were restored, resulting in better adherence of the insecticides on the leaves' surfaces; the residual toxicity was increased.
Effect of mulching and kaolin foliar spray on mung (Vigna radiata) – rapeseed (Brassica campestris) double cropping system under rainfed conditions
Authors: de Rajat , Giri Gajendra 
Published: March 2009

SummaryResults are described of an experiment made at the Indian Agricultural Research Institute, New Delhi, for 4 years under semi-arid seasonally dry tropical conditions to explore the possibilities of double cropping in the traditionally monocropped areas. Use of straw mulch did not increase mung yield in the monsoon season with welldistributed rainfall but increased its yield in a year when the monsoon receded early. Irrespective of rainfall pattern, mulching helped conserve enough moisture in the top 30 cm of soil to enable germination and quick establishment of the rapeseed crop. Mulching continued in the rapeseed crop conserved soil moisture until the flowering stage and increased the yield of rapeseed by 23%. Kaolin, a reflectant material applied at the preflowering stage, also increased seed yield of rapeseed.
Regrowth characteristics of an S. 23 perennial ryegrass sward defoliated at early stages of reproductive development
Authors: Davies Ieuan 
Published: March 2009

SummaryPatterns of stem development in late spring/summer regrowths after initial cuts at three growth stages are described. The stages at which the initial cuts were taken were: (a) before stem apices were raised to defoliation level (5 cm), (b) two weeks later when the apices of about 90% of the stem tillers were raised above this height, and (c) four weeks after (a), when the apices of all stem tillers were raised well above cutting height.Following an initial cut at stage (a) stem development was quickly resumed, the most advanced tillers being devoid of leaf blades. After initial cuts at the later stages there was virtually no stem development until after the fourth week of regrowth.The greater proportion of stem tillers in the earlier regrowth was not reflected in reduced digestibility during the first six weeks from cutting.Reproductive (apical) development was generally weak in tillers in which stems developed in midsummer (after cutting at stages b and c); at least two-thirds of these tillers were indeterminate.The significance of the distinct batch of stem tillers developing in spring is discussed, and the data are also considered in relation to (i) avoiding stemmy regrowths in spring, (ii) stem development and herbage quality, and (iii) summer stem extension and the perennation of the sward.
The effect of quality and quantity of carbohydrate and protein in the ration of the sheep on the digestibility of cellulose and other constituents of the ration, with a note on the effect of adding vitamins of the B-complex on the digestibility and retention of the nutrients of a hay ration
Authors: Head M. J. 
Published: March 2009

1. The effects of various starch and protein supplements on the digestibility of cellulose determined by the Norman-Jenkins technique and other constituents of the ration were studied in sheep.2. The addition of small amounts of maize or potato starch or flaked maize to a ration of about 1 lb. of poor hay was associated with a depression in the digestibility of (Norman-Jenkins) cellulose.3. When tested separately at varying levels, the addition of nearly pure maize protein, casein, white fishmeal, decorticated groundnut cake meal, urea or urea + DL-methionine, had no effect on the digestibility of cellulose, at any particular level of starch equivalent.4. The digestibility of nitrogenous nutrients was depressed by the addition of maize starch or flaked maize to the ration except when urea was the nitrogen supplement. The depression was even greater when potato starch was added to the ration instead of maize starch.5. The retention of nitrogen was not decreased by the addition of starch to the ration, although the digestibility of nitrogen-containing material was depressed. The retention was increased when starch was added to a ration containing casein.6. The retention of nitrogen was poor from rations containing urea and starch, but it was slightly improved by the supplementation with 1 g. DL-methionine per day.7. The addition of the various supplements had no marked effect on the digestibility of the dry matter or ‘other nutrients’ of the ration.8. It is suggested that the growth of the microorganisms digesting cellulose in the rumen is not dependent on the supplementary feed nitrogen when the substrate they are digesting contains a reasonable amount of nitrogen. This amount appears to be about 1%.9. The addition of vitamins of the B-complex to a daily ration of 1100 g. of hay did not affect the digestibility of the dry matter or nitrogencontaining substances or the retention of nitrogen by sheep.
The relationship in acid soils between base saturation and phosphorus uptake by grasses
Authors: Birch H. F. 
Published: March 2009

Analyses of grass samples from seventeen fertilizer trials on acid soil showed that both the percentage phosphate in the grass and the amount of phosphate removed by the crop were significantly and directly related to the percentage saturation of the b.e.c. of the soil. The amount of acid-soluble phosphate by difference (Table 1, A — B) was also significantly and directly related to the percentage phosphate in the grass but not to the amount taken up by the crop. The amounts of exchangeable bases, exchangeable calcium and acid-soluble, adsorbed and watersoluble forms of phosphate showed no significant relationships with phosphate uptake and percentage phosphate in the grass.The percentage saturation of the b.e.c. was found to be, on the average, about five times as effective a contributory factor to the percentage phosphate in the grass as the amount of acid-soluble phosphate by difference. The results confirm previous work, which indicated that in acid soils the main form of available phosphate is that associated with the exchangeable bases the effective presence of which is governed by the percentage saturation of the b.e.c. It is considered that phosphate availability and response in acid soils are best assessed by considering the percentage saturation of the b.e.c. rather than the amounts of some form or forms of phosphate in the soil.The grass analyses also showed that when the amount of phosphorus (P) hi the dry grass exceeds 0·33% no response to phosphate is to be expected. When the percentage in the grass is less than 0·23% responses of 10% or more are likely.
Methods of applying fertilizers for herbage crops
Authors: Cooke G. W. , Widdowson F. V. 
Published: March 2009

Phosphate-potash fertilizer was drilled in bands 20 in. apart and 3 in. below the soil surface and compared with similar dressings broadcast on the surface for established crops of sainfoin. On unmanured plots yields were not reduced by cutting grooves for the fertilizer bands. Broadcasting fertilizer on the surface produced consistently more sainfoin hay than dressings placed in bands. In similar experiments on permanent grass broadcast fertilizer also gave consistently more hay than bands of fertilizer placed 10 in.apart. Intheabsence of fertilizer small decreases in yields of grass were caused by cutting grooves. The advantages of an equal supply of nutrients to all the plants in an established sward, obtained by broadcasting fertilizers, outweighs any disadvantage from confining the application to the soil surface.Two experiments on lucerne in 1950–51 compared broadcast dressings of phosphate-potash fertilizer harrowed into the seed-bed with the same quantities of fertilizer placed in one band 2 in. to the side of the seed. Side-band placement did not give better early growth than broadcasting. Broadcast fertilizer gave higher yields of hay than placed fertilizer at one centre in the first year. There were no significant differences at either centre between yields of hay given by broadcast and placed fertilizer in the second year. When the dressings were divided, half being applied at sowing-time and the remainder in the spring of the following year, slightly lower yields were obtained than from dressings applied wholly at sowing.A further experiment on lucerne was laid down in spring 1952. Superphosphate, muriate of potash and a mixture of the two fertilizers were compared both when broadcast and ploughed in and when broadcast on the seed-bed. All the dressings of broadcast fertilizer were tested in the presence and absence of a ‘starter-dose’ of superphosphate drilled directly beneath the seed. The ‘starter-dose’ gave much better early growth and higher yields of lucerne than any of the dressings of broadcast phosphate and potash. Broadcast fertilizer ploughed in tended to give higher yields at the first cutting than seedbed dressings. At the second cutting there was little difference between yields given by ploughed-in dressings and dressings broadcast on the seed-bed.There is no case for introducing special equipment to place fertilizer in bands below the surface of established swards. For establishing lucerne and other ley crops, where fertilizers may be applied at or before sowing, there are no advantages from using special drills to place the full dressing of fertilizer at a safe distance to the side of the seed. Where combine-drills are used for sowing herbage crops they should be modified to place a small quantity of superphosphate directly beneath the seed and the remainder of the fertilizer should be broadcast before sowing.
Population dynamics of the Dexter breed of cattle
Authors: Young G. B. 
Published: March 2009

1. It is possible for a breed of cattle to persist and to expand slowly, despite the existence of a genetic defect which prevents 50% of the calves born being used for breeding. Moreover, it is possible to exert a certain amount of selection in such a breed. The Dexter breed provides an example.2. Before 1924, about 64% of entrants to the breed were from inspected animals. Between 1924 and 1939 the breed contracted. From 1940 to 1947 the breed expanded.3. During the period of decline almost every Dexter-type female born was registered and raised. The wastage rate and age distribution of the cows are similar in Dexters to those of other breeds. There would appear to have been comparatively little breeding from Kerry types. The average registered reproductive rate of Dexter-type females was about 0·8.4. While it was not possible to examine the breed structure in the period of expansion, this was probably accomplished by lengthening the average productive life of the female, and possibly also by breeding from Kerry types.5. The possibility of exercising selection in Dexters is shown to exist. Only about 13% of the females registered are used for producing registered bulls. Of the total bull crop, only about 7% are used to produce registered females, but the bulls selected have different numbers of offspring. The use of bulls selected after progeny testing is hardly feasible in Dexters. The increased numbers of females necessary in order to produce an adequate number of heifers, renders this technique almost impossible.6. There has been little inbreeding in Dexters. This is possibly due to deliberate policy, as some of the breeders associate inbreeding with the production of monstrous calves.7. It would, therefore, appear that the damaging effect of a lethal in a breed could be overemphasized.
Fatty acid composition of tail, subcutaneous and kidney fats of fat-tailed Awassi sheep
Authors: Al-Shabibi M. M. A. , Juma K. H. 
Published: March 2009

SummaryFatty acid composition of tail fat (TF), kidney fat (KF) and subcutaneous fat from the rumps (SCF) of docked and intact fat-tailed Awassi sheep was studied.Docking had no effect on the composition of KF. Kidney fat possessed harder characteristics due to its relatively higher content of saturated fatty acids as compared with SCF or TF.