bluuebunny/crossref_metadata_2025_split huggingface dataset:
Studies on the adaptability of three breeds of sheep to a tropical environment modified by altitude IV. Role of the fleece in thermoregulation in German Merino ewes
Authors: Symington R. B. 
Published: March 2009

The influence of fleece on thermoregulation in German Merino ewes was investigated in Rhodesia. Comparative heat tolerances of Persian Blackhead, indigenous Native and shorn and unshorn Merino ewes were obtained during the hottest month of the year in Northern Rhodesia. The main thermolytic responses in unshorn, partially shorn and completely shorn Merino ewes were measured at 7.0 a.m.; 10.0 a.m.; 1.0 p.m. and 4.0 p.m. during April in Southern Rhodesia.1. Unshorn Merino ewes showed more and shorn Merino ewes less effective body temperature regulation than Persian or Native ewes. High heat tolerance in unshorn Merinos was due primarily to insulation by the fleece and not to more efficient physiological thermolysis than in hair breeds. No ewe showed signs of undue thermal stress and feed intake was not affected by heat.2. Increases in rectal temperature and respiratory rate between 7.0 a.m. and 1.0 p.m. of Merinos in Southern Rhodesia were related inversely to fleece length. Body temperature did not differ significantly at 1.0 p.m. owing to differential rates of increase in respiratory rate.3. Magnitude of the diurnal fluctuation in skin temperature was also related inversely to fleece length. Partially shorn ewes, however, began with and maintained highest skin temperature through the heat of the day. In all groups skin temperature fell after 10.0 a.m. although ambient temperature continued to rise. This fall could not be attributed to sweating since moisture secretion declined simultaneously.
The apparent digestibility of the non-nitrogenous components of ruminant feeds
Authors: Glover J. , Dougall H. W. 
Published: March 2009

The digestibility of the non-protein constituents (almost entirely carbohydrate) of ruminant fodders is shown to be a function of the level of the crudefibre and crude-protein components.The effect of increasing crude fibre in the diet is to depress the digestibility of carbohydrate, irrespective of the level of crude protein associated with it.The effect of crude protein on the digestibility of carbohydrate is only well marked when its concentration in the dry feed lies below some 5%, that is when the feed is below approximate maintenance levels. Increasing the crude-protein content of the diet from some 2 to about 5% leads to increased digestibility of carbohydrate, but thereafter in the range of some 6–30% crude protein the protein effect is very slightly depressing to carbohydrate digestibility and is apparently quite negligible at average crude-fibre concentrations to be expected at any given level of crude protein.The implications of the various aspects of this paper are that the variability in digestibility of the non-nitrogenous component of ruminant feeds depends mainly on the respective levels of crude protein and crude fibre in the diet and to a very much lesser extent, if at all, on the species of ruminant or class of feed, be it silage, roughage or even mixture.
The total digestible nutrients and gross digestible energy of ruminant feeds
Authors: Glover J. , Duthie D. W. , Dougall H. W. 
Published: March 2009

It is shown that reasonable estimates of the average amounts of total digestible nutrients and gross digestible energy of ruminant feeds can be derived from knowledge of only the crude-protein and crude-fibre contents of such material as fed. These estimates do not appear to be markedly affected, if at all, by differences in class of feed or species of ruminant whether cattle, sheep or goat.A table of the average estimates of digestible crude protein and total digestible nutrients, to be expected at different levels of crude protein and crude fibre, is presented for use in the estimation of the average nutritive value of feeds whose digestibility has not been studied in detail by means of numerous animal trials.Inherent in the relationship between either total digestible nutrients or gross digestible energy and the proximate partial composition of the feed is a suggestion that if a low plane of protein nutrition is prolonged, that is when the crude protein of the dry diet lies persistently below some 5% in the dry feed, there is likely to be a sharp fall in the total digestibility of the feed.
Exogenous progesterone and oestrous cycle length in the ewe
Authors: Thwaites C. J. 
Published: March 2009

SummaryOne hundred and sixty mature Merino ewes were randomly allocated to a factorial experiment designed to investigate the effects of short-term progesterone administration on oestrous cycle length. Groups of ewes received a series of four daily injections of 0, 10, 25 or 40 mg progesterone in peanut oil beginning either on the day of oestrus (day 0) or the next day. Equal numbers of ewes (ten per group) received subcutaneous and intramuscular injections, and those in the control groups received injections of the vehicle only.Oestrous cycle length was significantly reduced in all progesterone-treated groups, but a consistent trend for this reduction to be greatest in ewes treated first on day 0 gave rise to a significant ‘day x dose’ interaction (P < 0·001). Route of progesterone administration had no significant effect on subsequent cycle length which, in control ewes, averaged 17·2 ± 0·1 days. For ewes first treated on days 0 and 1, mean oestrous cycle lengths for groups receiving 0, 10, 25 and 40 mg of progesterone per day were 17·3, 14·6, 12·1 and 10·7 days and 17·1, 15·2, 13·6 and 13·0 days respectively.
An evaluation of the properties of soil potassium influencing its supply by diffusion to plant roots in soil
Authors: Bagshaw R. , Vaidyanathan L. V. , Nye P. H. 
Published: March 2009

SUMMARYK+ uptakes from forty-four arable soils from England by 1 cm portions of the roots of intact onion seedlings during 10 days growth were measured. A single-split-root arrangement was used, enabling the determination of uptake by known surface area of the root. Transpiration was restricted to make K+ diffusion in the soil the predominant supply mechanism. These were compared with calculated values using separately determined K+ diffusion coefficients in the soils.Two methods were followed, namely (a) measuring K+ diffusion to a hydrogen form of cation exchange resin paper and calculating diffusion coefficients assuming total depletion of the (ammonium acetate) exchangeable K+ at the resin paper: soil boundary; and (b) deriving diffusion coefficients from estimated values of the impedance factor and the measured K+ buffer power of each soil, for 50, 60, 90 and 100% depletion of the initial soil solution K+at the root:soil boundary. None of the predictions adequately accounted for the observed uptake. Calculations of the root:soil boundary concentrations showed a wide range of depletion. Soils with initial soil solution K+ in the range 0.04–0.4 μmoles/ml were depleted of the solution K+ to near zero or even less. A negative concentration of K+ in solution indicates the probable contribution of non-exchangeable K+. When the initial soil solution K+ was more than 0.4 μmoles/ml, the uptake of K+ could be accounted for by 30–85 % depletion at the root:soil boundary.Partial and multiple regression of the measured uptake on the initial exchangeable K+ content and the initial soil solution K+ concentration were calculated. A simple relationship between the uptake and the exchangeable K+ content accounted for about three-quarters the variance. The uptake was less closely associated with the K+ in solution or its ratio to Ca2+ + Mg2+ in solution. These correlations are discussed from the diffusion point of view and in relation to the usually reported correlations from pot experiments.Potato yield response to K+ fertilizer additions in field experiments are examined in relation to the supply of K+ by diffusion in the soils. When K+ uptake by 1 cm portion of onion root from the unfertilized soil exceeded l.2 μmoles/10 days, yield response to K+ addition became erratic and occasionally negative.
Effects on barley and kale of NPK fertilizers containing differing proportions of urea and ammonium nitrate, and either triple superphosphate or mono-urea phosphate
Authors: Widdowson F. V. , Penny A. 
Published: March 2009

SUMMARYOf eight experimental fertilizers (with %N; %P2O5; %K2O ratios of 2:1:1) obtained, four contained triple superphosphate and four mono-urea phosphate; all contained muriate of potash. In the first four, urea supplied either 100, 66, 33 or 0% of the total N (ammonium nitrate supplied the remainder); in the second four, urea and ammonium nitrate supplied only the balance of the N, but in the same proportions.For barley, each fertilizer was combine-drilled to give 0·5 or 1·0 cwt N/acre. In 1965, much rain fell after drilling, early growth was not harmed and yields from each fertilizer were the same. In 1966, dry weather followed sowing and all fertilizers checked growth; those containing urea killed many plants and diminished yields. Also, yields from the fertilizers containing urea phosphate were larger than from those containing superphosphate; thus urea phosphate was safer than urea alone. For kale, the fertilizers were broadcast in May to give 1·25 or 2·50 cwt N/acre. None seriously diminished plant number and yields from all were similar.Increasing the proportion of urea in the fertilizers greatly increased %N in the barley grain in 1966, but not in 1965. The crops recovered more N from ammonium nitrate than from urea.
The lactation of Persian Blackhead ewes and the growth of lambs: The effect of three different nutritional regimes during gestation on subsequent growth
Authors: Butterworth M. H. , Blore T. W. D. 
Published: March 2009

SUMMARYForty-two Persian Blackhead ewes were used to investigate the effect of three prenatal planes of nutrition 6 weeks before lambing on birth weights and weights at 4 and 12 weeks after birth of their progeny. Nutritional regimes were: good grazing with concentrate supplement (high), good grazing without supplement (medium) and poor grazing without supplement (low). Pastures used were rotationally grazed Pangola grass. High-plane ewes gained significantly more weight during the last 6 weeks of gestation than ewes of the other two groups. Ewes nursing twin lambs lost significantly more weight than ewes nursing singles during the first 4 weeks of lactation. Birth weights of male single lambs and lambs from mature ewes were significantly affected by the prenatal plane of nutrition of the ewe. Lambs from mature ewes weighed significantly more than lambs from maiden ewes and male lambs weighed significantly more than females. Live-weight gains to 4 weeks were significantly affected by prenatal plane of nutrition in all cases. Type of birth was an important factor affecting growth rate and maturity of the ewe less so. Male lambs gained more weight than females during this period. Similar tendencies were apparent during the growth period of 4–12 weeks after birth although rate of gain was lower.
Infertile bulls versus steers: II. Feed conversion efficiency and the effects of a high fat diet
Authors: Price M. A. , Yeates N. T. M. 
Published: March 2009

SummaryThe feed conversion efficiency of four intensively fed, partially castrated male cattle, measured over an 11-week period from approximately 9-months of age, was found to be significantly higher (P <0·05) than that of four steers.The effect of adding 5% beef tallow to the diet during this period was also studied. Although no statistically significant result of this on feed conversion was obtained, there was an indication that fat in the diet improved the bulls' efficiency, but not that of the steers. Added dietary fat had an effect on carcass composition, increasing signifioantly (P < 0·05) the deposition of carcass fat by steers but having no such effect in bulls. It appears, therefore, that the two sex types metabolized the added dietary fat differently, the steers converting much of it to depot fat; the bulls using it (with some evidenoe of greater efficiency) for growth of non-adipose carcass components.
Physiological and economic feasibility of hormonally induced ovulation in lactating Large White sows
Authors: Epstein H. , Kadmon S. 
Published: March 2009

SUMMARYEighty-nine lactating sows, which had farrowed at least once before, were given 140 injections with 2000, 1800 or 1500 i.u. pregnant mare serum hormone. Seventy sows served as controls. 124 injections with 2000 i.u. P.M.S. were followed by 113 oestrus reactions and 88 pregnancies, and 16 injections with 1800 or 1500 i.u. by eleven instances of oestrus and six of pregnancy.Oestrus occurred in 69% of the positive reactors on the 5th day after injection, and in the rest either earlier or later. The interval between the P.M.S. injection and the onset of oestrus was similar to that between weaning and oestrus in the controls.The difference between the pregnancy rate of 71% following injection with 2000 i.u. P.M.S. and that of 83% in the control sows from the first oestrus after weaning was found to be statistically highly significant.Mean litter size and weight were not affected by different time intervals between farrowing and P.M.S. injection, nor were there any statistically significant differences in size and weight of litters at birth or at weaning at 8 weeks of age between those of hormonally treated sowsand the controls.The shortening of the farrowing interval by P.M.S. injection had no after-effect on the sizeand weight of litters subsequently obtained with or without hormone application.Injections with 1800 or 1500 i.u. P.M.S. were followed by a reduced pregnancy rate, but the few litters thus obtained were similar in mean size and weight to those obtained with 2000 i.u.or those of the controls.Sows that did not come on heat or become pregnant following P.M.S. injection came into heat at the same times after weaning of their litters as the control sows.The shortening of the farrowing interval by an average of 22 days was considered to be of sufficiently high economic value to warrant the introduction on the farm where the experiment wasconducted of the routine application of 2000 i.u. P.M.S. to all gilts and sows on the 28th day after farrowing.
Relationships of yields of maize and cotton, and their response to phosphate fertilizer, with soil phosphate potentials in Tanzania
Authors: Addiscott T. M. 
Published: March 2009

SUMMARYYields of maize and cotton given N, and sometimes K but no P, were related to equilibrium values of the monocalcium phosphate potential (½pCa+pH2PO4)eq', at which P is neither lost nor gained by the soil. The responses to phosphate fertilizer were not clearly related to phosphate potentials though small responses at large values of (½pCa+pH2PO4)eq were sometimes explained by very small values of δI/δQ (the rate of change of ½pCa+pH2PO4with change in the amount of P on the soil) or by soil reaction. In only one set of maize experiments, response to P was related to δI/δQ. (½pCa+pH2PO4)0 and (pH2PO4)0', determined without adding P to the solution, were equally useful and both were just as well related to yields without P as (½pCa+pH2PO4)eq' (pH2PO4)0 appeared more useful than the logarithm of the total P concentration measured without added P. It wa not necessary to find the equilibrium phosphate potential, or to measure Ca concentration, but correcting the phosphate concentration for pH (so that only H2PO4-ions were taken into account)was worth while.
Prediction of body compostion of sheep from tritiated water space and body weight—tests of published equations
Authors: Searle T. W. 
Published: March 2009

SUMMARYThe body composition of parasite-infected sheep and of healthy sheep of various body weights and breeding was predicted from tritiated water (TOH) space and body weight using previously published regression equations. Results agreed well with body composition determined by analysis of the minced carcass though a small bias existed in some groups. It is concluded that the equations have a general application to the prediction of body composition in sheep.
The effect of seedling disturbance on the growth habit and yield of swedes
Authors: Lang R. W. , Holmes J. C. 
Published: March 2009

SUMMARYThe effect of seedling disturbance on the yield and growth habit of swedes was studied in ten experiments during the period 1960–3. Seedling disturbance consisted of the removal of soil from around the seedlings during singling, thus exposing the hypocotyl and leaving the seedlings prostrate.Plant numbers were reduced slightly by seedling disturbance in half the experiments but not sufficiently to be a source of yield loss at the populations attained.Seedling disturbance greatly increased the incidence of prostrate growth in swede varieties of intermediate shape, such as Victory. Two globe-shaped varieties, Bangholm and Pentland Harvester, grew erect irrespective of singling technique.Disturbance of seedlings reduced yield when it increased the number of prostrategrowing plants. The yield depression ranged from 0·2 to 5·2 cwt D.M./acre.
Effects of nitrogen fertilizer, plant population and irrigation on sugar beet: III. Water consumption
Authors: Draycott A. P. , Durrant M. J. 
Published: March 2009

SUMMARYA neutron moderation meter was used to measure soil moisture 0–4 feet deep in plots of sugar beet carrying two plant populations (8800 and 54000 plants/acre), each with and without irrigation. Recordings began in April or May in each of three years (1967–9) after sowing the crop and continued at 1 or 2-;week intervals until harvest in October.The measured soil moisture deficits were very similar to potential deficits calculated from meteorological measurements. This indicates that the crop could extract the water needed for transpiration from the soil even when the deficits were quite large (more than 5 in in 1967), which probably explains the small response to irrigation by sugar beet in England.When the soil moisture deficit increased rapidly early during the season (1967), the crop extracted water from the soil by exhausting the available water from progressively deeper horizons, whereas when the deficit increased rapidly late during the season (1969) water was still being extracted from all horizons until harvest. Both decreasing the plant population and irrigating decreased the amount of water used from depth in the profile every year.The total amount of water used (evaporation plus transpiration), on average, from soil reserves and rainfall, was 12·2 in by the small population and 13·4 in by the large population. When irrigated, the consumption increased to 14·2 and 15·4 in. respectively. The difference in usage between populations was almost entirely from the difference in leaf cover early during the season. The water consumption in 1968, when the summer was wet, was only two-thirds of that in 1967 and 1969 when the summers were drier.
The relationship between the yields of eight varieties of Nigerian maize and content of nitrogen, phosphorus and potassium in the leaf at flowering stage
Authors: Agboola Akinola A. 
Published: March 2009

SUMMARYStudies of the relationship between yield and content of N, P and K in the ear leaf of eight varieties of Nigerian maize, tested for three growing seasons, indicated that the varieties have different critical nutrient levels, although the values obtained for individual varieties were not significantly different from the pooled average critical level for any of the nutrients. The critical levels ranged from 2·85 to 3·19% N, 0·20 to 0·27% P and 2·06 to 2·60% K, while their pooled averages were 3·10% N, 0·23% P and 2·44% K.High ear leaf nutrient content was not a guarantee of high grain yield, and ear leaf nutrient values of low-yielding varieties were similar to those of the high-yielding varieties.
Effect of crude fibre upon feeding efficiency of cattle in ‘warm’ environments
Authors: Vohnout K. , Bateman J. V. 
Published: March 2009

SUMMARYResults of this study show that daily intake of dry matter (DM) and digestible energy (DE) was lower for the ‘warm’ environment and ‘high’ fibre groups. Efficiency of DM utilization was also lower for these groups. However, efficiency of DE was essentially the same for both rations, being lower in the ‘warm’ group. The lower intake in the ‘warm’ environment was attributed mainly to the longer length of time that animals spent resting, which resulted also in lower growth rates. The data indicate that increasing the caloric density of feed, to compensate for reduced consumption, would make it possible to obtain proportional increases in energy intake. As interactions were negligible, this situation would apply to both environments studied.
A comparison between the effect of various photoperiods on the reproductive performance of Scottish Half-bred ewes
Authors: Newton J. E. , Betts J. E. 
Published: March 2009

SUMMARYFour experiments are described in which attempts were made to increase the number of live lambs born per ewe per unit time. In the first experiment 22 Scottish Half-bred ewes were subjected to an artificial photoperiod. This resulted in 95 % of the ewes being mated 128 days after their previous lambing. It was estimated that artificial photoperiod brought the breeding season forward by about 5 weeks. The use of 1500 i.u. Pregnant Mare Serum had no significant effect on mean litter size. In the second experiment three artificial photoperiods were compared with natural daylength. In Group 2 photoperiod was decreased rapidly on 2 April from 18 to 10 h, in Group 3 photoperiod was decreased gradually on 2 April from 24 h and in Group 4 photoperiod was decreased rapidly on 28 May from 18 to 10 h. Group 5 was the control. Median intervals from parturition to next conception for Groups 2–5 were 70, 138, 68 and 131–5 days respectively; median intervals from onset of decreasing daylength to conception were 129, 200, 83 and 118–5 days respectively. Treatments 2 and 4 significantly reduced the interval from parturition to next conception but treatment 3 was unsuccessful. The interval from onset of decreasing daylength to conception was significantly shorter for treatment 4 than for treatment 2.In Exp. 3 an unsuccessful attempt was made to extend the natural breeding season by preventing photoperiod from increasing for 3 months after 22 December.In Exp. 4 a similar photoperiodic pattern was used for Groups 9 and 10 (16 h photoperiod decreasing rapidly to 8 h on 18 February). The contrast was that in Group 9 most of the ‘light’ was natural, in Group 10 all the ‘light’ was artificial. This pattern was compared with the natural daylength pattern (Group 8), an equinoctial treatment (Group 11) and a short-day treatment, 8h light, 16 h dark (Group 12). The median intervals from parturition to next conception for Groups 8–12 were 194, 102, 99, 156, 155 days, respectively. There was no significant difference in this interval between Groups 9 or 10. Type of ‘light’ therefore had no influence on the median interval from parturition to next conception; but photoperiodic pattern did. A rapid increase to 16 h light followed by a rapid decrease to 8 h (Groups 9, 10) was more effective than either the equinoctial treatment (Group 11) or the short-day treatment (Group 12). The treatments imposed on Groups 11 and 12 were more effective in shortening the median interval from parturition to next conception than the natural daylength pattern (Group 8). Time of year of mating had no effect on lambing percentage.It was concluded that the sensitivity of sheep to photo-stimulation varied directly, with time from the onset of the next natural breeding season and with the speed of photoperiodic decrease.