Showing papers in "The Journal of Agricultural Science in 1962"
TL;DR: A rapid and accurate atomic absorption method for the determination of chromium in faeces samples from pasture experiments using chromic oxide "markers" is described in this article, where the effects of these interferences were overcome by adding calcium to the test solution and by the addition of silicate to the standards, which were prepared in ‘blank’ solutions.
Abstract: A rapid and accurate atomic absorption method for the determination of chromium in faeces samples from pasture experiments using chromic oxide ‘markers’ is described. Of the elements present after ashing and digesting the samples in a phosphoric acid—manganese sulphate—potassium bromate solution silicate, aluminium, calcium and magnesium were found to interfere in the determination. The effects of these interferences were overcome by the addition of calcium to the test solution and by the addition of silicate to the standards, which were prepared in ‘blank’ solutions.The sensitivities of a number of alternate chromium resonance lines relative to that of Cr 3578·7 A. are given. These lines may be used to increase the concentration range of the analysis.The results of a comparison of the atomic absorption method with a chemical method are given.
1,848 citations
TL;DR: It is found that one problem in cattle is that of silent heat, the condition where ovulation is not accompanied by the usual symptoms of oestrus, and there is clear evidence of a dose-response relationship over the dosage range employed.
Abstract: 1. In the course of a 2-year field trial (1959–60) conducted in mid-Wales, 525 cattle were entered by 317 co-operating farmers for treatment with p.m.s. in the induction of multiple-pregnancy. Most animals were commercial, non-pedigree cattle maintained in accord with local custom. The cattle were of mixed ages and included some milking cows as well as animals used in calf rearing. 2. The method of hormone treatment tested consists of a single subcutaneous injection of a freeze-dried preparation of p.m.s. administered in the follicular phase of the oestrous cycle. Most cows were injected 16 or 17 days after a previous oestrus and bred by a.i. at the heat period following injection. 3. Of the 525 cattle injected 416 provide comprehensive data on factors affecting ovulatory response; seventy cattle, which had a ‘silent heat’ after injection, provide additional but partial information. In thirty-nine cattle, it was not possible to obtain reliable evidence of response. Data on ovulation and pregnancy were obtained by examinations per rectum conducted during the early weeks of pregnancy. 4. Ovulation data relate to 416 cows which were injected, came in oestrus shortly afterwards and inseminated, then examined for evidence of fresh corporea lutea at the following mid-cycle stage. Five dosage levels of p.m.s. were employed (800, 1000, 1200, 1600 and 2000 i.u.). The normal process of ovulation did not appear adversely affected by any of the doses employed. 173 of the 416 cows (41·6%) produced more than one egg. 5. There is clear evidence of a dose-response relationship over the dosage range employed. The mean number of ovulations varies from 1·43 at 800 i.u. to 3·97 at 2000 i.u. The percentage of cattle shedding additional eggs rises from 33 at 800 i.u. to 56–6 at 2,000 i.u., but increasing dosage level leads to considerable variability in ovulatory response: range of ovulations at 800 i.u. is 1–5, and at 2000 i.u. is 1–25. 6. Little affect was observed in ovulatory response according to the stage of p.m.s. administration. At low dosage levels, an interval of at least 2 days between injection and oestrus was necessary to allow response to occur. Among factors affecting response to a standard dose of p.m.s., lactation and state of normal ovarian activity appeared to have some importance. There was no evidence of an effect on cycle length. Treatment did not give rise to abnormal mating behaviour and the incidence of adverse side-effects following p.m.s. injection was negligible. The occurrence of large unovulated follicles occurred more frequently following treatment with 2000 i.u. than with lesser dosage levels. 59·1% of all ovulations occurred in the right ovary and 40·9% in the left. In examinations made prior to injection, the incidence of spontaneous double ovulations was 4·1%. 7. With the p.m.s. approach, it is found that one problem in cattle is that of silent heat, the condition where ovulation is not accompanied by the usual symptoms of oestrus. In 486 animals for which information was obtained, silent heat occurred in 70 (14·4%). There is some tendency for the condition to occur more frequently where low dosage levels are used or where p.m.s. is administered very late in the oestrous cycle. Lactation appears to affect the incidence of the defect. The lowest incidence (4·8%) occurs in ‘dry’ cows and the highest (22·7%) in cattle rearing three to four calves. Superovulation occurred less frequently at silent heat than at normal oestrus. There is no evidence that p.m.s. injection is the direct cause of the condition. It appears that time of ovulation in animals showing silent heat is comparable with that for cattle showing the normal symptoms. 8. Of the 416 cattle put to a.i. shortly after p.m.s. administration, 317 (76·2%) were pregnant when examined some 6 weeks after first insemination. This compares closely with the normal 30–60 day non-return figure for the mid-Wales area (78·5%). Cattle conceived as readily after injection with 2000 i.u. as after treatment with 800 i.u. Even where animals shed many eggs (e.g. more than six) the conception percentage (84·0) was high. It is clear that this form of therapy does not adversely affect the processes of ovulation, fertilization and implantation. There is some suggestion that p.m.s. aided conception in repeat-breeder cattle. Examinations in the mid-cycle stage following a.i. did not adversely affect conception. 9. Data on the number of eggs surviving (as foetuses) in the 6th week after mating, in relation to the initial number of ovulations, clearly show a heavy loss in eggs in early pregnancy. 41·6% of cattle shed additional eggs but only 23·1% possessed multiples in early pregnancy. 10. Reduction to a single foetus seemed particularly liable to occur in cattle producing two eggs-only. Of sixty-seven double-ovulating animals that conceived, thirty-two possessed twins at the 6th week (47·7%). The survival of both eggs in such cows was better when one egg was shed by each ovary (61·5%) than where both ovulations occurred in the one ovary (28·6%). Analysis of data on egg survival according to factors such as age, breed, time of treatment did not reveal differences. 11. Trans-uterine migration of eggs was rarely (1 case in 197 examinations) noted. The ability of a single uterine horn to sustain more than two foetuses was limited. In cattle where three to six eggs were shed by an ovary, the survival of twins in the associated uterine horn was observed in a majority (57%) of cases. Where many eggs (ten to fifteen) were shed by an ovary, twins were rarely sustained by the associated uterine horn. 12. A steady increase in the percentage of cows carrying multiples (at 6 weeks) was noted over the dosage range employed. 20·8% of cows injected with 800 i.u. carried multiples, the figures for doses of 1000, 1200 1600, and 2000 i.u. being 25·2, 31·3, 41·7 and 42·7, respectively. Multiples in the form of triplets and quadruplets occurred more frequently at the higher dosage levels than at 800–1000 i.u. of all cows with multiples considered, 36·5% possessed more than two foetuses at examination in the 6th week. 13. Pregnancy diagnosis examinations were conducted over a period ranging from 35 to 101 days after mating, with most falling in the period 41–44 days. It appeared that the most appropriate time for diagnosing multiples was at the end of the 6th week of pregnancy. The need to conduct diagnosis at a specific time after mating, and the fact that the examination may lead to total litter loss in many animals, makes the procedure unsuitable for any widespread practice. Partial litter loss (loss of one foetus) was observed in 12·5% of cows carrying twins at 6 weeks and in 20·0% of those with triplets. 14. In nineteen cows, each possessing either three or four foetuses, an attempt was made in the 6th week of pregnancy to control litter size to two. This was by rupture of excess amniotic vesicles by manipulation per rectum. Two of those so treated eventually produced calves, the others either aborting or returning in oestrus soon after the control procedure. The method is unsuitable for farm application for reason of the delay in returning to normal breeding after such cases of failure of pregnancy. 15. A substantial proportion (32·5%) of those cows which were subjected to pregnancy diagnosis lost the conceptus a short time afterwards. Foetal loss in cows with twins was greater (43–46%) where foetuses were both in the one horn than where distributed between both horns (31%). The various factors which were possibly involved in foetal loss are discussed. Evidence was obtained that total foetal loss occurred more frequently in animals shedding many eggs than in those shedding few. 16. Information is recorded for 147 injected cattle which produced single calves following conception at the oestrus immediately following hormone treatment. Additional data on single calvings are provided by 200 untreated cattle which were studied in the area of the trial. These data show birth weight of single calves to be 78·6 lb., and the incidence of calf mortality, retention of foetal membranes and difficult calvings to be 4·9, and 6·0%, respectively. The mean duration of the gestation period was 283·4 days. 17. The outcome of multiple calving was observed in forty-four cattle (thirty-five sets of twins, eight sets of triplets and one set of quintuplets). As a result of earlier examinations, farmers were usually alert to the fact that cows were carrying twins. Herd owners were encouraged to provide such cows with an additional 2 cwt. of a suitable concentrate feed during the final 2 months of pregnancy. Although a number of herd owners followed the recommended feeding programme, in a number of instances the most appropriate pre-calving preparation was not given. The outcome of calvings in relation to the level of additional feeding is considered under three headings, high, moderate and low plane. 18. Given good feeding (high plane) the outcome of twin calvings was satisfactory. Results suggest that the problems often associated with twins (low-weight calves, high rate of mortality, retained foetal membranes, loss of conditon and poor subsequent breeding of the dam) may largely be overcome by an adequate ‘steaming-up’ policy. In cows adequately prepared, birth weight ranging from 59 to 89 lb. were recorded (mean 73·9 lb.) Mean gestation was a little less (280·6 days) than for singles. The incidence of retained foetal membranes (18·2%) was greater than that for single-bearing cows, but did not constitute a serious problem in any animal. 19. Less satisfactory results were noted in cows not given adequate preparation for twins. Where triplets were carried, the outcome for cow and calves, regardless of the feeding attention given, was unsatisfactory. Triplet-bearing cows calved earlier, and the incidence of retained foetal membranes, difficult calvings and calf deaths was much above that noted for the twin
84 citations
TL;DR: There is evidence that the holocellulose and xylan in grasses are different from those in legumes in the extent to which they are digested, and it is suggested that this is due mainly to thexylans or hemicellulose fraction in the forages, and may be a reflexion of a different molecular structure for the xylans in either group.
Abstract: There is a strong correlation between the digestibility of the organic matter and the percentage crude fibre, percentage lignin, and percentage cellulose plus lignin in the foodstuffs examined.There is evidence that the holocellulose and xylan in grasses are different from those in legumes in the extent to which they are digested. It is suggested that this is due mainly to the xylans or hemicellulose fraction in the forages, and may be a reflexion of a different molecular structure for the xylans in either group.Within each group of plants both the holocellulose and xylan percentages are strongly correlated to the percentage digestible organic matter.Excessive heating of hay led to a marked rise in the percentage lignin. This is probably due to the xylans becoming horny and insoluble, therefore being determined as lignin. This also offers an explanation for the decrease in digestibility of the organic matter.
74 citations
TL;DR: The relationship between the soluble carbohydrate carbon/soluble nitrogen ratio in grass with no nitrogen was 18 at the first sampling and it increased gradually, reaching 70 at the last sampling.
Abstract: Italian rye-grass given ammonium sulphate or sodium nitrate at 56 or 112 lb. N/acre was analysed for total nitrogen, soluble nitrogen (non-protein-nitrogen) and soluble carbohydrates.Ten days after applying fertilizer the differences in total-N between the grass receiving 56 and grass receiving 112 lb. N/acre were very small. Total-N in grass decreased with growth, but the effect of the rate of nitrogen on total-N increased. At first the grass given sodium nitrate contained more soluble nitrogen than grass given ammonium sulphate, the difference being greater at 56 lb. N/acre; soluble nitrogen decreased with increasing growth. Ten days after applying fertilizer, the nitrate-N content of grass was very high (ranging from 0·1 to 0·9% in the D.M.) and it gradually decreased. At both levels of nitrogen application, grass given sodium nitrate contained much more nitrate-N than grass given ammonium sulphate. Forty days after applying nitrogen the nitrate-N contents of grass which received 56 and 112 1b. N/acre as ammonium sulphate were 0·039 and 0·222% of the dry matter, respectively; the grass supplied with sodium nitrate gave values of 0·082 and 0·438%.Total soluble carbohydrates in the grass were small early in growth and gradually increased. Nitrogen dressings had little effect on the content of soluble sugars (glucose + fructose + sucrose) but greatly decreased the fructosan. The pattern of changes in the total soluble carbohydrate content followed that in fructosan content. Early in growth, the total soluble carbohydrate/crude protein ratio was very small in grass from all treatments except the ‘control’. This ratio increased with growth and at the last sampling was 2·13 in grass receiving no nitrogen, and in grass supplied with 56 and 112 lb. N/acre as ammonium sulphate it was 1·44 and 0·72 respectively; the corresponding figures for grass receiving sodium nitrate were 1·13 and 0·66. The total soluble carbohydrate carbon/soluble nitrogen ratio in grass with no nitrogen was 18 at the first sampling and it increased gradually, reaching 70 at the last sampling. This ratio was considerably less with all nitrogen treatments than with ‘control’. The values obtained with 112 lb. N/acre were less than those obtained with 561b./acre, irrespective of the form of nitrogen used.The relationship between the soluble carbohydrate carbon content and the soluble nitrogen in grass is illustrated graphically and discussed.
65 citations
TL;DR: The results confirm that fixation or release are determined by the extent to which the soil contains more or less exchangeable potassium than its equilibrium percentage potassium saturation.
Abstract: The relationship between the exchangeable potassium content of a soil and the activity ratio, aK/√(aCa+Mg), of the solution with which it is in ‘instantaneous equilibrium’ is a characteristic of the soil which is independent of the soil: solution ratio or the total electrolyte concentration (up to O·06 M) of the solution. It is unaffected by the transfer of substantial amounts of potassium ions to or from the fixed state. Hence instantaneous equilibrium curves provide a basis against which to measure the changes in exchangeable potassium content due to fixation and release. This procedure has the important advantages that all measurements are made in the solution phase and that the solutions in contact with the soil approximate to the natural soil solution. The technique has been employed successfully in studying the fixation and release of potassium by several widely different soils. The results confirm that fixation or release are determined by the extent to which the soil contains more or less exchangeable potassium than its equilibrium percentage potassium saturation. Seemingly the equilibrium percentage potassium saturation, and hence the equilibrium activity ratio of potassium in the soil solution aK/√(aCa+Mg), is regulated by the amounts or proportions of potassium in the fixed state. The amounts or proportions of potassium in the fixed state may be increased by repeated applications of potassium fertilizers and reduced by continued cropping.
60 citations
TL;DR: It was concluded that, in a temperate climate, variations in the skin temperatures of the extremities of the ox have a thermoregulatory function.
Abstract: 1. Measurements of the temperatures of the extremities, rectal temperatures, respiratory rates and heart rates have been made in calves during exposure at environmental temperatures within the range – 5·0° –45·0° C.2. Large variations in the skin temperatures of the extremities were recorded between environmental temperatures of –5·0° and 25·0° C. At environmental temperatures above 25·0° C. the extremity temperatures and the skin temperatures of the trunk were similar.3. Feeding and localized infra-red irradiation of part of the trunk of the animals resulted in marked increases in the skin temperatures of the unheated extremities.4. Evidence was obtained that the variations in the skin temperatures of the extremities were brought about by changes of blood flow to these parts.5. Respiratory rates varied also with the environmental temperature at which the animals were exposed. When the animals were exposed to localized infra-red irradiation of the trunk the increase in respiratory rate was significantly greater when the extremities were initially warm than when they were cool.6. In addition to spontaneous fluctuations in the skin temperatures of the ears at environmental temperatures of 10·0°–25·0° C, periodic increases in the skin temperatures of the ears were observed in all the calves at an environmental temperature of – 5·0° C. The increase in the skin temperatures of the ears persisted throughout the 7 hr. exposure to an environmental temperature of – 5·0° C.7. It was concluded that, in a temperate climate, variations in the skin temperatures of the extremities of the ox have a thermoregulatory function.
60 citations
TL;DR: The weights of the two sides of the twenty carcasses were similar, although the loins of the left sides were highly significantly heavier than those from the right sides and the right fores were highly significant heavier than the left fores.
Abstract: 1. Twenty Southdown-Romney wether lamb carcasses of a mean hot carcass weight of 39·2 lb. (range 31·2–43·8 lb.) were frozen. Each frozen carcass was divided down the back-bone to give two sides and each side was divided into four parts: leg, loin, 9–10–11 rib cut, and fore. A method of obtaining samples from the parts and from the sides is described. The samples were analysed for water, fat (uncorrected), and residue (uncorrected). The dried residue was analysed to give an ash percentage and a Soxhlet correction factor so that total fat (ether-extract), protein (dried fat-free, ash-free residue), and ash were determined.2. The weights of the two sides of the twenty carcasses were similar, although the loins of the left sides were highly significantly heavier than those from the right sides and the right fores were highly significantly heavier than the left fores.3. The mean percentage composition of the two sides of the carcasses studied were similar. Likewise each of the four parts showed close similarity between sides except for the residue and protein percentage of the loin in which the left sides had significantly more protein percentage than the right sides. In all the uncorrected chemical components a significant side × carcass interaction was found.4. An analysis of the sampling errors showed that the variance of a treatment mean was decreased only slightly by increasing the number of samples per side or by sampling both sides instead of one. Any substantial increase in precision can be achieved only by increasing the number of carcasses per group.
56 citations
TL;DR: The design of an experiment to measure the responses of ordinary farm crops to supplementary irrigation in a part of England where, from meteorological reasoning, the frequency of need was expected to be about 2 years in 3.
Abstract: Part I, largely introductory, outlines the design of an experiment to measure the responses of ordinary farm crops to supplementary irrigation in a part of England where, from meteorological reasoning, the frequency of need was expected to be about 2 years in 3. The watering treatments were based on estimates of potential transpiration, made from weekly weather data collected on the site, and measured rainfall. The basis of the computation is restated, and the balance of rain and estimated transpiration plotted for each of the 9 years, week by week in summer, month by month in winter. The meteorological specification of frequency of need was satisfied in 5 of the years, during which twenty crops were taken. Of these, eighteen responded to irrigation. In the other years, four of the sixteen crops responded positively to irrigation, and a few of the remaining twelve responded negatively when early irrigation was followed by summer rainfall sufficiently in excess to cause leaching from irrigated plots.
46 citations
TL;DR: This paper reports on the behaviour of one variety of Lolium perenne, S. 24, grown in a logarithmically related series of densities and frequently defoliated for 2 years, measuring plant performance in a wide range of field environments.
Abstract: 1. To evaluate selection criteria in grass breeding, a series of investigations was conducted measuring plant performance in a wide range of field environments.2. This paper reports on the behaviour of one variety of Lolium perenne, S. 24, grown in a logarithmically related series of densities and frequently defoliated for 2 years. Half the plots received only natural rainfall, the rest were irrigated so that the calculated soil moisture deficit did not exceed 2 in.3. In 1958, with little effect of irrigation, swards yielded most per unit area, widest spacing (24 in.) least; there were no significant differences in yields from the other densities (3, 6 and 12 in.). In 1959, when yields were lower, irrigation increased production in all plots, the higher the density the greater the increase. In contrast to 1958, over the range of spaced densities, the higher the density the greater the yield. Individual harvests did not always conform to the annual pattern.4. Lowest mean production per plant was from broadcast plots in both 1958 and 1959, yields of plants from 3, 6 and 12 in. plots showed a linear increase with a reduction in density, those from 24 in., though heaviest, yielded less than linear expectation. In 1959 irrigation increased yields per plant.5. Of the components of yield, number of sterile tillers gave the best estimate of total fresh weight (95·3% reliability). However, total number of tillers (sterile plus fertile) was almost as efficient (94%). Tiller weight was a much less reliable index.6. The results and their value in establishing efficient criteria for selection in grass breeding are discussed.
46 citations
TL;DR: The energy cost of gain is less than that of pen-fed sheep and it is suggested that this is due to the maintenance cost decreasing with increasing availability of pasture and with increasing gain, and the exponent of live weight agrees well with the estimates of other workers based on pen- fed animals.
Abstract: The intake of grazing sheep in terms of digestible organic matter, DOM, has been measured by faecal index methods, employing chromic oxide to measure faecal output and faecal nitrogen for digestibility of pasture. A regression equation for the prediction of digestibility from faecal nitrogen (organic matter basis) was developed from several series of digestibility trials with pasture, the equation beingdigestibility of organic matter = 30·84 + Four trials to measure maintenance and gain were conducted, as follows:(i) Thirty-eight sheep, comprising twelve wethers of mean weight 112 lb., thirteen small or thin Romney ewes of mean live weight 110 lb. and thirteen large or fat Romney ewes of mean live weight 166 lb. were grazed all together for 17 weeks on a rye-grass-white clover sward at an intensity such that live weight was just maintained. Corrections to intake were made for small live-weight changes.Daily DOM intake (lb.) for maintenance = 0·062 maintenance for a 100 lb. sheep becomes 1·48 ± 0·08 lb. DOM/day.(ii) Thirty-six weaned Romney ewe lambs of mean initial live weight 56 lb. were grazed for 8 weeks on a rye-grass-white clover pasture and allowed to gain in weight. Regression of intake on gain gave the equationdaily DOM intake (56 lb. lamb) = 0·93 (±0·07) + 0·90 gwhere g = gain in lb./day. Combining this lamb data with that of the previous trial yields the equationDOM intake (lb.) for maintenance = 0·052 (iii) Forty ewes, comprising eight Southdowns, twelve Romneys, eight Border Leicesters and twelve Border-Romney crossbreds were grazed together on short pasture (rye-grass-white clover) for 12 weeks. The ewes were of widely differing live weight and the mean gains or losses of the groups over the period varied from + 1·5 to −4·5 lb.Daily DOM intake (lb.) for maintenance = 0·061 which for a 100 lb. sheep becomes 1·63 ± 0·13 lb. DOM.(iv) Seven Romney ewes were grazed in high and eight ewes in low intake groups for 8 weeks. Regression of intake on gain gave the equationdaily DOM intake (130 lb. ewe) = 1·58 (±0·06) + 1·98 g.For a 100 lb. sheep this becomes 1·36 (± 0·06) lb. DOM/day for maintenance.The three estimates of maintenance of a grazing sheep of 100 lb. live weight 1·48, 1·63 and 1·36 lb. DOM/day are greatly in excess of the estimate of 0·92 lb. DOM/day for pen-fed sheep. It is believed that this difference is outside experimental error and represents a true increase in energy cost due to grazing. It is suggested that the cause of this derives from the energy costs of walking and harvesting the pasture together with climatic factors wind, cold and rain. The exponent of live weight agrees well with the estimates of other workers based on pen-fed animals. The energy cost of gain is less than that of pen-fed sheep and it is suggested that this is due to the maintenance cost decreasing with increasing availability of pasture and with increasing gain.
45 citations
TL;DR: In this paper, the nitrate and total nitrogen contents were determined over a period of 14 days in a range of near neutral Ghanaian soils, and it was found that only small or non-significant losses of nitrogen occurred in the unsaturated soils, but larger and rapid losses were observed in the saturated samples.
Abstract: Denitrification has been studied in a range of near-neutral Ghanaian soils. The technique used was to add nitrate, alone or with glucose, to 10 or 15 g. samples and incubate at 30° C. and 70 or 160% of the water holding capacity. Changes in the nitrate and total nitrogen contents were then determined over a period of 14 days. Only small or non-significant losses of nitrogen occurred in the unsaturated soils, but larger and rapid losses were observed in the saturated samples. In the samples from under standing forest or old grassland denitrification proceeded without addition of a carbonaceous substrate, but a small addition was required in the cultivated and young grassland soils. The amount needed was much less than has been shown necessary for an equivalent nitrogen loss in a number of temperate zone soils. Evidence was obtained that nitrification and denitrification could proceed simultaneously in the same sample. It is c6nsidered that this supports the concept of a micro-mosaic of aerobic and anaerobic spots in a wet soil.
TL;DR: It was found that with the exception of a few parts, the percentage which the parts constituted of the carcass remained remarkably constant in the various groups of beef steers, and the effect of age in both the fattened and unfattened groups was comparatively small.
Abstract: 1. The effect of fattening, age and the ratio of concentrates to roughage in a ration on the development of beef steers was investigated. The specific purpose was to study developmental patterns during the short-term fattening of beef steers of different ages in order to ascertain to what extent beef steers improved in the proportions of the various body parts, offals, organs and tissues. 2. The experimental material consisted of 104 beef steers of three age-groups, namely, ± 8, ± 20 and ± 32 months old, fed on rations differing in the ratio of concentrates to roughage and 36 control steers of the same age-groups, slaughtered at the start of the experiment. 3. When the weights of the parts of the carcasses were expressed as a percentage of the carcass weight, it was found that with the exception of a few parts, the percentage which the parts constituted of the carcass remained remarkably constant in the various groups. The effect of age in both the fattened and unfattened groups was comparatively small, whilst the effect of fattening was of slightly greater magnitude. The effect of the ration concentration per se was negligible. 4. The parts where fat was deposited formed a significantly ( P 5. The shoulder, chuck and buttock and rump, formed a significantly ( P
TL;DR: Four experiments have been conducted with sheep, housed and fed in pens, to determine the maintenance and live-weight gain requirements of sheep under such conditions and the mean estimate of maintenance was 1·00 ± 0·11 lb.
Abstract: Four experiments have been conducted with sheep, housed and fed in pens, to determine the maintenance and live-weight gain requirements of sheep under such conditions.1. Fifteen Corriedale sheep of initial live weight 115 lb. were fed at maintenance for 13 weeks. Daily DOM (digestible organic matter) requirement for maintenance was 0·92 ± 0·07 lb.2. Twelve Romney ewes of mean live weight 106 lb. over the period were fed for 5 months, six on submaintenance and six on super-maintenance levels. Daily DOM requirement for maintenance was 0·99 ± 0·05 lb., and requirement for gain 2·29 ± 0·20 lb. DOM per lb. gain or loss.3. Thirteen Romney ewes of mean live weight 110 lb. over the period were fed at sub- and supermaintenance levels for 8 weeks yielding the result: daily DOM intake for maintenance 1·04 ± 0·13 lb. and for gain 2·25 ± 0·24 lb. DOM per lb. gain.4. Twenty-four Romney ewes of initial live weight 107 lb. were randomized into five groups and fed fresh grass, dried grass, sheep pellets, lucerne hay and rye-grass straw for 11 weeks at slightly below maintenance. There were no significant differences between groups and the mean estimate of maintenance was 1·00 ± 0·11 lb. DOM per day.Converting these estimates to those of a 100 lb. sheep using the ¾ power of live weight, and then taking the mean gives the final estimate for maintenance of a 100 lb. sheep 0·92 lb. DOM, 0·96 TDN or 0·89 lb. SE.
Abstract: A grass/clover ley (mainly S26 cocksfoot and S 100 white clover 3 years, 1951–53) and a pure grass stand (S 37 cocksfoot 6 years, 1954–59) on the same site had threefold replication of four irrigation treatments: O, unwatered control; C, kept near field capacity throughout; A and B, intermediate between O and C. All plots received the same basic P and K dressing, and half-plots got N dressings either as N1 and N2, or as N2 and N4, the nitrogen being applied in the spring and after every cut except the last at rates: N1 0·15; N2, 0·30; N4, 0·60 cwt. N/acre. Cuts were taken at about 3 or 4 week intervals in the summer, and yields expressed as dry matter.
TL;DR: In this paper, the authors investigated the relationship between the percentage of fat in the subcutaneous and intermuscular fatty tissues and the iodine number of the extracted fat from eight anatomical joints (foreshin, neck, shoulder, thorax, loin, pelvis, leg and hindshin) and from the perinephric fatty tissue and psoas muscles of the carcasses from twenty-four animals.
Abstract: 1. An investigation has been carried out concerning the percentage of fat in the subcutaneous and intermuscular fatty tissues and in the muscular tissues, and the iodine number of the extracted fat from eight anatomical joints (foreshin, neck, shoulder, thorax, loin, pelvis, leg and hindshin) and from the perinephric fatty tissue and psoas muscles of the carcasses from twenty-four animals. The animals were from three breeds (Hereford, Dairy Shorthorn and Friesian) and were on four levels of nutrition—high-high and medium-high, and high-medium and medium-medium. The first two groups—finished on concentrates—were younger than the second two groups—finished on grass. 2. Using an analysis of variance for the resultant data for percentage of fat and iodine number, it was found that breed had affected the percentage of fat in the tissues of the various joints significantly—on the average the order was Shorthorn (highest), Hereford and Friesian (lowest). This result could be predicted from the fact that this was the order of fatness of the carcasses (as measured by the percentage of fatty tissue in the carcass—see Callow, 1961). 3. The data for iodine number showed no significant effect for breed in either the subcutaneous or intermuscular tissues. The significant effect of breed in the case of muscle could be attributed to significant differences in the overall level of fatness (see Callow, 1961) of the carcasses of the three breeds. 4. A good correlation existed between the average percentage of fat in a joint and the average iodine number of fat extracted when the data for various joints was used to calculate straight lines of best fit. (In the case of muscular tissue, it was necessary to use the inverse of the percentage of fat to calculate the average—because the relation between the percentage of fat in muscular tissue and its iodine number is a rectangular hyperbola.) 5. Using such lines of best fit, it was possible to show that certain joints had tissues which gave abnormal values for iodine number. Thus, deepseated tissues, like psoas muscle and kidney fat, had unexpectedly low values, whilst tissues from the hindshin had unexpectedly high values. This was attributed to the effect of local temperature—a high local temperature in the body giving a lower iodine number and a low temperature a higher iodine number than would otherwise be expected. The special case of subcutaneous fat from the thorax—with a higher iodine number than expected—is explained by the presence of brisket fat (which has a high iodine number). 6. The data were used graphically to show the effect of growth gradients, thus the average percentage of fat in all the tissues is lowest in fore- and hindshins and highest in thorax (muscular and intermuscular tissues) and in the pelvis (subcutaneous tissue). Similar effects, but in the reverse direction, were shown by average values for iodine numbers. 7. There were systematic differences in the percentage of fat in the subcutaneous and intermuscular tissues of joints and in the iodine number of the extracted fat. These too showed marked growth gradients. Although the percentage of fat in the intermuscular tissue was greater than that in the subcutaneous tissue in the fore- and hindshins, it was less in the thorax, loin, pelvis and leg. In spite of this, the iodine number of the subcutaneous fat was always higher than that of the intermuscular fat. This is attributed to the former being a colder tissue than the latter. 8. It was shown that the relation between iodine number and percentage of fat in the various joints was different for the animals finished on grass (highmoderate and moderate-moderate levels of nutrition) as compared with those finished on concentrates (high-high and moderate-high levels). This was attributed to the rate of fattening being greater in the second case and to this giving rise to lower iodine numbers. 9. Beyond this effect of rate of fattening, no reason could be found for the fact that the general level of iodine numbers showed variation from animal to animal. 10. The extreme variation in percentage of fat in the tissues was (a) muscular tissue from 1·3 to 14·5%, (b) intermuscular tissue from 29·5 to 82·7%, and (c) subcutaneous tissue from 25·2 to 89·8%. For iodine number the variation was (a) 50·0 to 73·9, (b) 42·9 to 67·9 and (c) 46·3 to 67·9 It is thus clear that beef can be a very variable foodstuff.
TL;DR: In this article, a number of penned feeding and grazing experiments are described in which sheep and cattle, fed diets of low-quality roughage, were given supplements of urea and molasses, or Urea and starch.
Abstract: 1. A number of penned feeding and grazing experiments are described in which sheep and cattle, fed diets of low-quality roughage, were given supplements of urea and molasses, or urea and starch.2. Starch was unsatisfactory as a source of supplementary carbohydrate, and it was concluded that this was mainly due to its low palatability. Molasses added without urea to a diet of straw for penned sheep increased intake and reduced the rate of live-weight loss in one experiment, but had no effect in another.3. In general, supplementing low-quality rough-age with urea and molasses in both penned feeding and grazing experiments increased food intake and reduced the rate of live-weight loss. A supplement of urea alone increased food intake, but did not affect live-weight loss. The addition of ethanol or phosphoric acid to urea-molasses supplements had no additional beneficial effect. Supplementation with urea and molasses increased wool growth, but this increase was not always significant.4. The general effect of urea on rumen contents was to increase pH, V.F.A. and ammonia N levels; the effect of molasses was to decrease pH and ammonia N levels, and increase V.F.A. levels.5. Spraying of dry, standing herbage with urea and molasses increased the crude protein (N × 6·25) content, but this effect disappeared in 3–4 days. Sprayed herbage was markedly preferred by grazing animals, and generally one third of the sprayed herbage was removed within 24 hr. of spraying.6. The advantages and disadvantages of the pasture-spraying technique, and the possibilities of other methods of feeding supplements containing urea to grazing animals, are discussed.7. In no experiment where unsupplemented animals were losing weight did urea and molasses supplementation cause substantial increases in weight. It is concluded that the main value of supplementing low-quality roughage with urea and molasses would be for the survival, and possibly the maintenance, of animals.
TL;DR: In this article, the crude-protein and mineral content of pastures at Muguga have been investigated, and the difficulties of interpreting such data have been considered, and it is shown that the amounts present of all substances determined largely depended upon the amount of recent rain.
Abstract: 1. Variations in the crude-protein and mineral content of pastures at Muguga are described. 2. At all times sodium appeared to be inadequate, and during dry periods phosphorus and crude protein were also apparently deficient. 3. Except for sodium and calcium, the amounts present of all substances determined largely depended upon the amount of recent rain. 4. The difficulties of interpreting such data have been considered.
TL;DR: The maternal influence on birth weight in cattle is in both qualitative and quantitative agreement with the maternal influence as derived from egg transfer studies in sheep.
Abstract: This study is based on 1015 live single calves brod by artificial insemination in a herd of Ayrshire, Friesian, Jersey and two-breed and three-breed cross cattle derived from them. Birth weights, subjected to a least squares analysis, show little effect of year or season of calving. Males were 6·0 lb. heavier than females; second and later parity calves were 6·6 lb. heavier than first parity calves. Over the range of breeds and crosses studied, heredity was the principal determinant of mean birth weight. No evidence of heterosis was found— means for crossbred calves, however, differed in reciprocal crosses. They deviated from the mean of the parents in the direction of the maternal weight at birth. If 0 is the mean birth weight of the dam's breed or cross and 0 of the sire's breed, the mean weight of offspring is closely estimated by This expression may not apply to the crossing of breeds differing much more in weight than the Jersey and Friesian breeds. In such crosses it is likely that small dams depress foetal growth more than large dams promote it. The maternal influence on birth weight in cattle as expressed above is in both qualitative and quantitative agreement with the maternal influence as derived from egg transfer studies in sheep. It is a pleasure to record the authors' heavy obligations to many friends for help during the course of this long experiment. The Milk Marketing Board, in the persons of Dr J. Edwards, C.B.E., Mr T. O'Sullivan, and their colleagues at the A.I. centres made the breeding programme possible. Much time has been saved and much statistical computation cut short by the help afforded us at the Rothamsted Statistical Department by Dr F. Yates and his staff, particularly Mr J. H. A. Dunwoody. Responsibility for the animals on the farms fell at first upon Mr W. S. Biggar, and from 1950 upon Mr J. S. Tavernor. They were aided by many of whom mention must be made of Mr H. L. Williams, Mr R. Pringle and Mr R. Simpson. In the preparation of this paper the authors have been much influenced by the work and criticism of their colleagues.
TL;DR: The ‘availability’ of the magnesium of diets consisting solely of roughage or succulent feeds, including herbages cut at different seasons and at different stages of growth, and of diets of hay supplemented with various concentrate feeds was assessed in metabolism trials conducted with two non-pregnant, non-lactating Shorthorn cows.
Abstract: 1. The ‘availability’ of the magnesium of diets consisting solely of roughage or succulent feeds, including herbages cut at different seasons and at different stages of growth, and of diets of hay supplemented with various concentrate feeds, was assessed in metabolism trials conducted with two non-pregnant, non-lactating Shorthorn cows. 2. The highest daily intakes of magnesium (1720 g./day) were provided by a diet of red clover: grasses and hays generally gave a considerably lower intake of magnesium (8–10 g./day), and most of the other diets provided intermediate amounts. However, with timothy hay and barley straw, intakes of 5 and 2 g./day, respectively, were recorded. Supplements to a diet of hay of dairy cubes or of oilcakes rich in protein gave a massive increase in magnesium intake but a supplement of flaked maize provided little additional magnesium. 3. The ‘availability’ of the magnesium of the diets was generally low, within the range of 5–30%. With diets of single feeds no clear distinction between the various roughages and succulents in the ‘availability’ of their magnesium was established, though within the group of herbages the lowest values tended to occur with grasses cut at an early stage of growth and the highest values at the mature stage. A supplement of flaked maize increased the ‘availability’ of dietary magnesium and one of protein-rich oil cakes decreased the ‘availability’ of dietary magnesium. 4. The results are discussed in relation to the development of hypomagnesaemia in cattle grazing spring pasture.
TL;DR: In light sandy soils, where vertical structural fissures are absent, nitrate becomes distributed down the profile on leaching and most of the nitrate disappears from the profile after removal, by leaching or denitrification, from the cultivation layer as discussed by the authors.
Abstract: 1. The pattern of downward movement of nitrate in light soil is different from that in heavy clay soil of the kind used in this work.2. In light sandy soils, where vertical structural fissures are absent, nitrate becomes distributed down the profile on leaching.3. In heavy soils, which are well fissured and possess a gleyed horizon of partially decomposed plant debris at cultivation depth, most of the nitrate disappears from the profile after removal, by leaching or denitrification, from the cultivation layer.4. There is little difference in the amount of rain required to remove nitrate from the surface layers of light or heavy soil.5. Heavy and continuous rain is required to remove nitrate completely from either light or heavy soils.6. Nitrification of ammonium sulphate is more rapid in summer than winter, but nitrification does proceed slowly during winter.7. Ammonium nitrogen is not leached from the surface layer of either light or heavy soil.
TL;DR: During the periods under consideration the proportion of muscle in the carcass exceeded that of the other tissues, however, while the rates of growth of muscle and bone were similar the growth rate of fat was markedly greater.
Abstract: 1. Results are presented concerning the gross composition of pig carcasses at 50, 68 and 92 kg. carcass weight in ten litters. They show that during the periods under consideration the proportion of muscle in the carcass exceeded that of the other tissues. However, while the rates of growth of muscle and bone were similar the growth rate of fat was markedly greater. The result was that at 92 kg. the proportions of muscle and fat in the carcass were 43·53 and 41·37%, respectively.2. Results are also presented dealing with the relative development of the different parts of the skeleton. Of the five major anatomical regions of the skeleton the sacrum grew relatively fastest between 50 and 68 kg. carcass weight while the cervical vertebrae grew fastest in the second period. In both periods the bones of the thorax and loin grew at rates intermediate between the fastest and slowest growing regions.
TL;DR: Artificial feeding, divided into three equal feeds per day at 05.00, 13.00 and 21.00 hr. for the first 2 months, would be reasonably consistent with natural suckling activities if restrictive feeding has to be applied, but further work is required to determine the cost.
Abstract: 1. The habits of five Tanganyika Shorthorn zebus and their suckling calves were studied during periods of 72 consecutive hours at monthly intervals in each of the first 6 months of the calves' lives, during the ‘dry’ season of the year.2. Cows grazed for 7·16 hr. per day while grass was green and plentiful, but, as grazing became dry and sparse, they ate silage at night for up to 3 hr., and reduced their grazing time by about 2 hr. The ratio of rumination time to eating time tended to increase as grazing became drier and as silage eating increased. The average ratio was 1·01 to 1.3. All calves were actively grazing for 4·0 hr. per day by the second month, and for 5·6 hr. per day by the fifth month. They ate silage diffidently in the second month, but they were eating silage for 1·7 hr. per night at 6 months. Rumination was observed in a calf at 18 days of age, but was consistently observed in the second month when calves ruminated for 6·1 hr. per day. The ratio of rumination time to grazing time for calves declined from 1·5 to 1 in the second month to 1·1 to 1 in the fifth month. Rumination time among calves was more closely related to silage eating than to grazing time.4. The calves acted as individuals in the first month, and thereafter their eating habits were determined more by their dam than by their age. Day-time rumination pattern was a characteristic of the age of calf, but night-time rumination by calves was more closely correlated to that of their dams.5. Calves suckled for an average period of 9·2 min. per suckle. There was very little variation with age, but frequency of suckles decreased from 9·5 times per day at 1 month to 5·6 times per day at 6 months. The fastest-growing calf suckled less frequently for shorter periods, suggesting readier availabilty of more milk.6. Suckling intensity was evenly spread over the 24 hr. during the first 2 months, but thereafter suckling became increasingly confined to nighttime while the cattle were yarded.7. It was concluded that artificial feeding divided into three equal feeds per day at 05.00, 13.00 and 21.00 hr. for the first 2 months, followed by two equal feeds per day at 05.00 and 18.00 hr., would be reasonably consistent with natural suckling activities if restrictive feeding has to be applied. But further work is required to determine the cost, in terms of reduced efficiency of milk utilization, incurred by concentration of intake to restricted feeding times.
TL;DR: Although the adult geese were two or three times as heavy as the adult fowls, the mean total gut capacity was proportionately less, and this effect was enhanced by the concurrent inclusion of procaine penicillin G.
Abstract: A study has been made of the internal volume of the different parts of the alimentary tract of geese and fowls. It has been shown that although the adult geese were two or three times as heavy as the adult fowls, the mean total gut capacity, exclusive of the crop, was proportionately less. Although the gizzard was much greater in weight than in the fowl, its capacity in proportion to body weight is only half that of the fowl, whilst the caeca are relatively even smaller. The distended oesophagus of the goose, which replaces the crop of the fowl, was at all times smaller relative to body weight. The gut capacities of both chicks and goslings increased rapidly when they began to feed, and reached a maximum, relative to body weight, within the first fortnight after hatching. At 16 weeks, the capacity of the alimentary canal had almost the same relation to body weight as in the adult. In both, the small intestine constitutes the major proportion of the volume in the adult, being 33–40% in the fowl and more than 50% in the goose. Feeding a diet containing 21% crude fibre and supplemented with procaine penicillin G produced chicks with relatively greater gut capacities, and this effect was enhanced by the concurrent inclusion of procaine penicillin G, but where the fibre was reduced to 17·4%, the gut capacities were not significantly different, in relation to body weight, than in the control group. Histological examination of the wall of the gut of chickens raised on different diets showed marked abrasion on high-fibre diets, and a much thinner intestinal wall in those birds receiving antibiotic.
TL;DR: In this article, the effects of height-of-cutting on herbage yields were studied for five seasons with a perennial rye-grass-white clover mixture and for three seasons with timothy-white mixture.
Abstract: 1. The effects of two heights of cutting—down to either 1 in. or 2–2½ in. from ground level—on herbage yields were studied for five seasons with a perennial rye-grass-white clover mixture and for three seasons with a timothy-white clover mixture. Superimposed on these height-of-cutting treatments were treatments simulating strip grazing with and without a back-fence, and also three fertilizer nitrogen treatments. 2. Over the 5-year period the rye-grass mixture consistently gave greater dry-matter and crude-protein yields of herbage when cut to 1 in. than it did when cut to 2–2½ in. from ground level, the mean dry-matter yield difference being 34%. The decline in the total yield per season with increasing age of the grass sward was similar under both heights of cutting. 3. The effects of the height-of-cutting treatments on the timothy mixture were similar to those noted on the rye-grass mixture in the first three seasons of the experiment, but in the third year the beneficial effects of close cutting were much reduced. It is suggested that this resulted from the rest period between cuts being insufficient for timothy to recover fully from the close defoliation. 4. The effects of the height-of-cutting treatments on the botanical composition of the sward were slight, particularly on plots of the rye-grass mixture. 5. Possible factors leading to the observed effects of the height-of-cutting treatments are discussed with reference to the results of other workers and to the results from a preliminary study of the differential effects of the treatments on stem and leaf formation in perennial rye-grass. 6. A simulation of strip grazing with and without a back-fence showed that the herbage yields from both seeds mixtures under both height-of-cutting treatments were considerably reduced by the removal of the regrowth which could take place in the absence of a back-fence. 7. The effects of delaying the first nitrogenoua fertilizer application of the season noted in an earlier experiment were fully confirmed in this experiment.
TL;DR: It was found that in two experiments the mean difference between Africander x Herefords and Hereford steers, mean body weights 863 and 686 lb.
Abstract: 1. Eight nitrogen metabolism experiments, each with sixteen steers representing grade Brahman, Brahman x Shorthorn, Africander x Hereford and Herefords, were carried out. The steers were fed according to body weight to the power 0·73, on rations consisting of natural pasture hay alone or in combination with lucerne hay.2. These experiments showed that the steers with zebu blood were significantly superior to the Herefords with regard to dry-matter digestibility and apparent nitrogen digestibility. The breed difference disappeared when nitrogen digestibility was calculated from the relationship feed nitrogen minus undigested faecal residue nitrogen, divided by feed nitrogen.3. Two further nitrogen metabolism experiments with six Africander x Hereford and four Hereford steers fed natural pasture hay plus lucerne hay, and one experiment with two Brahman x Shorthorn, two Africander x Hereford and two Hereford steers fed chaffed wheat straw were carried out. The steers were fed an equal amount of ration, irrespective of body weight.4. In these three experiments faecal nitrogen was fractionated into undigested residue nitrogen, non-dialysable centrifugable nitrogen, non-dialysable non-centrifugable nitrogen, and dialysable nitrogen. The breed groups differed significantly in the amount of dialysable faecal nitrogen excreted but not in any other component.5. The amount of dialysable faecal nitrogen excreted on equal intake was very significantly negatively correlated with body weight (r = −0·807, P < 0·01).6. It was found that in two experiments the mean difference between Africander x Herefords and Hereford steers, mean body weights 863 and 686 lb., respectively, was 1·81 ± 0·51 g. nitrogen per day. It was calculated that this would represent about 70 ± 20% of the body-weight difference between the breeds if the lost nitrogen was fully utilizable. This agreed well with the estimate of 65% derived from the square of the correlation coefficient.
TL;DR: In both spring and summer the increasing maturity of the herbage caused declines from one period to the next in herbage digestibility and intake, and there were declines also in milk yield and solids-not-fat content.
Abstract: 1. A group of four Ayrshire and four Friesian cows was strip grazed on a cocksfoot-dominant sward while a second, similar group was zero grazed on herbage cut from the same field. The experiment consisted of five 10-day periods, two in the spring and three in the summer.2. The intakes of all cows were calculated from values for faeces output, estimated by using chromic oxide, and for herbage digestibility, estimated from faeces nitrogen. The regressions used for predicting digestibility were determined with the zero-grazed cows, digestibility coefficients being calculated from measured intake and estimated faeces output values.3. Over the whole experiment there was no difference between treatments in milk yield, herbage digestibility or intake. The solids-not-fat content of the milk of strip-grazed cows was significantly higher than for zero-grazed cows.4. In both spring and summer the increasing maturity of the herbage caused declines from one period to the next in herbage digestibility and intake, and there were declines also in milk yield and solids-not-fat content. The declines were greater for the zero-grazed cows, apparently because they, unlike the strip-grazed animals, were unable to select the more digestible and palatable components of mature herbage. The effects of selective grazing on digestibility, however, were evidently small, for the difference in between the treatment groups was never greater than one unit.5. The estimated energy intakes of both treatment groups corresponded quite well with their theoretical requirements of energy for maintenance, milk production and live-weight gain, and there was no evidence of the energy cost of free grazing being appreciably greater than that of zero grazing.
TL;DR: It is suggested that, providing the diet is changed only in respect of quantity, important functional groups of rumen bacteria can survive at levels of food intake which are insufficient for the survival of the animal.
Abstract: 1. The composition of the bacterial population in the rumen of adult merino wethers conditioned to a diet of poor teff hay was studied during three consecutive periods of 60, 109 and 42 days when the ration was 1200,600 and 300 g. per day, respectively.2. In all three periods there was no significant difference between the three sheep with regard to either the viable counts of the functional groups of bacteria fermenting cellulose, starch, glucose, xylose and lactate or the percentage proportions of the different morphological types occurring in each group.3. The reduction of food intake had little or no influence on either the numbers or the morphological types of bacteria in each functional group.4. The animals lost weight at approximately the same rate throughout the three periods of the experiment which was ended when they were in a state of prostration.5. These results suggest that, providing the diet is changed only in respect of quantity, important functional groups of rumen bacteria can survive at levels of food intake which are insufficient for the survival of the animal.
TL;DR: The inter-relationships of starch and proteins during fermentation in the rumen are measured by estimating volatile fatty acids, ammonia, lactic acid and amino acids after administering the starch and protein supplements alone or together.
Abstract: 1. The inter-relationships of starch and proteins during fermentation in the rumen are measured by estimating volatile fatty acids, ammonia, lactic acid and amino acids after administering the starch and protein supplements alone or together. 2. The presence of casein stimulates the formation of volatile fatty acids from starch. Simpler nitrogen-containing compounds are less effective than casein; other proteins are as effective as casein provided they are fermented as rapidly in the rumen. 3. Proteins can be divided roughly into three groups on the basis of the rapidity with which they give rise to ammonia in the rumen: casein, gelatin, ground nut protein > soy protein, wheat gluten > bovine albumin, zein. 4. The proportion of acetic acid falls and of propionic acid and higher acids rises as proteins that are rapidly fermented are placed in the rumen.
TL;DR: The use of soil analyses in advising on P-manuring is discussed and a tentative method is proposed of establishing the analytical limits for soluble P that define ‘deficient’ soils as mentioned in this paper.
Abstract: Soil samples from 179 field experiments testing phosphate fertilizers on potatoes, swedes and grass were analysed for total phosphorus, and for phosphorus soluble in the following solutions: 0·3 N-HCl, 0·002 N-H2SO4, 1% citric acid (H3Ci), 0·5 N acetic acid (HAc), acetic acid-sodium acetate buffer (HAc-NaAc) at pH 4·8, 0·5 M-NaHCO3, and 0·01 M CaCl2.Average values for soluble P were closely related to average crop responses to superphosphate in the experiments on swedes, but not in the grass and potato experiments. The extractants that differentiated best between responsive and unresponsive groups of experiments were HAc, HAc-NaAc, and NaHCO3 for potatoes, and HCl, H2S04, HAc–NaAc, NaHCO3 and CaCl2 for grass.For the experiments as a whole 0·5 M-NaHCO3 was the ‘best’ extractant. The HCl, H2SO4, and HAc-NaAc buffer solution methods were roughly equally effective, though inferior to NaHCO3; the other three extractants (HAc, H3Ci, CaCl2) were of little general use. Total P in soil was also related to response to superphosphate, though less well than values for soluble P obtained by the better methods.Estimates of soluble P by different solvents were often related. Estimates by HCl and H2SO4 methods were most closely related; values for P soluble in H2SO4 and in HAc-NaAc were also often significantly correlated, as were estimates by HAc–NaAc and CaCl2. The H3Ci and CaCl2 methods gave results that were least related to those with other methods.The use of soil analyses in advising on P-manuring is discussed and a tentative method is proposed of establishing the analytical limits for soluble P that define ‘deficient’ soils. If the confidence attached to the limiting values that separate ‘deficient’ and ‘non-deficient’ soils is stated, farmers will be able to assess the risk entailed in accepting advice based on soil analysis.