bluuebunny/crossref_metadata_2025_split huggingface dataset:
The efficiency of utilization of grass by lactating ewes
Authors: Owen J. B. , Davies D. A. R. , Ridgman W. J. 
Published: March 2009

1. A study of grazing intake and efficiency was carried out on eighty-one ewes suckling twin lambs during early lactation.2. A method of estimating comparative grazing intake is described involving the administration of Cr2O3 and sampling from the pasture with the minimum of labour. The results indicated that reasonable precision was achieved with a method suitable for studying large numbers of animals. 3. The efficiency of production of lamb up to 5 weeks of age was not associated with the body weight of the ewe nor with the wither height. It was, however, negatively associated with grass intake by the ewe and to some extent with the gain in body weight by the ewe during lactation. Only in two of the four experiments was efficiency associated with lamb production up to 5 weeks.
Nitrogen metabolism in the lactating sow
Authors: Lodge G. A. 
Published: March 2009

1. Each of three litter sister sows was fed one of three levels of crude protein in the diet during two 8-day periods in the fourth and seventh weeks of lactation. The three protein levels were 11, 15 and 19% of the diet on an air-dry basis. The scale of feeding was varied to maintain each sow at constant weight throughout the 8-week lactation period.2. During two 3-day collection periods following 5-day preliminary periods, intake of nitrogen from the diet and outputs of nitrogen in faeces, urine and milk were measured.3. The sow receiving the medium level of protein in the diet was in positive nitrogen balance during both collection periods.4. The major effect of increasing the protein level of the diet was an increase in the output of urinary nitrogen. Neither milk yield nor output of protein in the milk appeared to be affected over the limited period studied.5. Apparent digestibility of dietary protein was 75% on the low level and 85% on the medium and high levels of intake.
The effect of pregnancy and fatness on the volume of rumen contents in the ewe
Authors: Forbes J. M. 
Published: March 2009

SUMMARYTwenty-seven ewes in various states of fatness, and either non-pregnant or between 72 and 144 days pregnant, were slaughtered and the volumes of digesta and abdominal organs were measured. There was a significant negative relationship between the volume of rumen contents and the volume of uterus plus abdominal fat plus other abdominal organs.
Self- and cross-fertility in field beans (Vicia faba Linn.)
Authors: Drayner Jean M. 
Published: March 2009

1. Controlled self- and cross-pollinations were performed on field bean plants. It was found that while manipulation of the flower stimulated seed setting, both self- and cross-pollination were equally effective.2. Estimations of pollen germination on artificial medium, to which had been added extracts of styles or ovaries from the same or a different plant, gave some slight evidence of a specific inhibition by ‘self’ extracts. No analogous effect was detected on pollen tube growth.3. Experiments in which the style was cut at varying intervals after pollination detected no difference between self- and foreign pollen in rate of growth through the style. Pollen placed on stigmas of immature flowers began growth at once although the fertility achieved was less than when mature flowers were used.4. The composition of seed from mixed self- and cross-pollination was examined. Early application of foreign pollen increased the proportion of crossfertilization but the results were similar in hybrids and inbreds.5. Flower manipulation was more effective in stimulating seed setting than shaking the plants. Spraying with hormone solution was ineffective.6. It was found that plants varied in their capacity to set seed without flower manipulation (autofertility). Hybrid plants were more autofertile than plants from inbred lines.7. X-ray pictures of unopened flowers suggested that the pollen may be more abundant and less diffuse in hybrids than in inbreds.8. The expression of autofertility was affected by many genetic factors.9. Seed produced by open pollination of F1 hybrids contained a much higher proportion derived from self-pollination than did seed from inbred plants grown in the same plot. Possible explanations for this difference, and some consequences for the population genetics of the species, are discussed.
The agronomic properties of urea-containing compound fertilizers:I. High-nitrogen type
Authors: Collier P. A. , Hood A. E. M. , Powell R. A. , Templeman W. G. 
Published: March 2009

SUMMARYThis paper reviews extensive work at Jealott's Hill and elsewhere in England and Wales on the agronomic effects of including various levels of urea in 2:1:1 NPK fertilizers combine-drilled with spring cereals.Little evidence of phytotoxicity was found with fertilizers containing up to 12% urea and providing about 0·6 cwt N/acre. The inclusion of 20% urea reduced braird more frequently on soils of high pH than did lower proportions although grain yields were seldom affected adversely. Such soils are not uncommon, especially in the barleygrowing areas of Southern and Eastern England, where perhaps a quarter of the cereal acreage may be located on soils of pH 7·7 and above.
Nutritional stress and pre-implantation embryonic mortality in Merino sheep, 1965
Authors: Edey T. N. 
Published: March 2009

SUMMARYOf 120 mature Merino ewes, balanced groups received the following treatments from days 8 to 15 after fertile mating: 1, submaintenance nutrition plus 10 mg/day progesterone; 2, submaintenance without progesterone; 3, maintenance nutrition plus progesterone as above; 4, maintenance nutrition without progesterone.The ewes were in light condition, they lost some weight before mating, they had an ovulation rate of 108·3% and they barely maintained their mating weight during the first 3 months of pregnancy. The percentages of ova shed not represented by lambs at term were 60·6, 58·1, 48·5 and 62·5 for groups 1–4 respectively. There were no significant treatment differences or interactions.The high overall loss of ova could have been due in part to depressed fertilization rate: however, the general environmental conditions and low body weight of the ewes seems likely to have made an important contribution to the high basal loss. There was a significant regression of prenatal mortality on body weight at mating, but no detectable relationship between prenatal mortality and condition score.Sixteen oestrous cycles of over 21 days were distributed through all groups, indicating that considerable mortality occurred after day 13.
The mean velocity and velocity distributions of normal bull spermatozoa at different hydrogen-ion concentrations, derived from photo-electric measurements
Authors: van Duijn C. , Rikmenspoel R. 
Published: March 2009

1. The mean velocity ῡ and the velocity frequency distribution f(υ) of bull spermatozoa with normal motility have been determined in standardized eggyolk—citrate buffers at different pH values, ranging frompH 5·70 to 8·35.Under assumed approximately anaerobic conditions at37·0 ± 0·1° C. the mean velocity was found to show a straight-line relationship -with pH in the physiological region pH 5·70–7·50, according to the general equationStatistically, k was shown to be a linear function of a, namely,Consequently, the dependence of the mean velocity of the spermatozoa from any ejaculate can be characterized by the one parameter a = dῡ/dpH. (dimension μ/sec./pH), determining the slope of the ῡ υs. pH curve.The mean velocity of all individual spermatozoa (measurements of all ejaculates at the same pH value pooled together) could be described accurately by the equation:For some ejaculates the linear relationship was found to hold up to pH 8·00.2. The velocity frequency distribution curves were found to change with pH. At pH 5·70 the curves are skew with a relatively high top value. At increasing pH values both the top value and skewness decrease. The mean standard deviation of the velocity distribution f(υ) was found to be proportional to pH and could be described by the equationThis means that the variability in swimming speeds of the individual spermatozoa of any ejaculate increases proportionally with pH, indicating a strain effect of increasing alkalinity on the population, irrespective of the general stimulation of motility in the region up to pH 7·50.3. At each pH value the mean velocity decreases with time. Under assumed approximately anaerobic conditions at 37° C. the speed of velocity decrease as a function of pH was found to differ so much between different ejaculates that no generalization could be derived from the available material. The same holds for the effect of pH on the number of normally moving spermatozoa in the diluted ejaculate.4. The total number of spermatozoa moving normally depends on pH, but the optimum varies with the individual ejaculates.
Studies on goat nutrition Part II. Digestible protein requirements for maintenance from balance studies
Authors: Majumdar B. N. 
Published: March 2009

1. The crude protein requirement of goats for maintenance has been determined from balance studies. The requirement per kg., as found by three different methods of treatments of the balance data, is practically the same, viz. 2·63 g. crude protein.2. The digestible crude protein requirement also has been calculated, again by two different methods, and is estimated at 1·12 lb./1000 lb. body weight. This value is undoubtedly very much higher than the value (0·65 lb./1000 lb.) obtained previously from the endogenous urinary nitrogen determinations alone.3. The dry-matter requirement of goat per 100 lb. live weight has been determined. Calculated on the basis of live weight raised to the power 0·734, the requirement was found to be 2·6 lb./100 lb.
A study of milk production of the grazing ewe, with emphasis on the experimental technique employed
Authors: Coombe J. B. , Wardrop I. D. , Tribe D. E. 
Published: March 2009

1. Milk yields of grazing ewes with single lambs were estimated using two methods—the traditional lamb-suckling technique, and a technique involving hand-milking following stimulated let-down by intravenous injection of posterior pituitary gland extract (known as the oxytocin technique).2. The oxytocin technique gave significantly higher figures for milk production than did the lamb-suckling technique (P< 0·01), and this persisted throughout lactation. Variation between ewes was similar for both techniques.3. The two techniques are discussed in relation to the errors involved, and their accuracy and convenience of application to field conditions.4. Differences in milk yield between Border Leicester x Merino ewes, and Romney Marsh x Merino ewes, estimated by either technique, were not significant. Correlation coefficients between lamb growth rate and milk yield of the ewe, measured by either technique, were high up to 7 weeks of age.5. Where the ewes were under the same nutritional conditions before and after lambing, milk yield was not related to the live weight of the ewe, or birth weight of the lamb.
Comparisons of casein and formalized casein with ammonium sulphate, calcium nitrate and urea for Italian ryegrass
Authors: Widdowson F. V. , Shaw K. 
Published: March 2009

1. Italian ryegrass, laid down for two years, was used to compare the value of casein and formalized casein, ammonium sulphate, calcium nitrate and urea for grassland production. Residual effects of these treatments were measured on a third-year crop of barley.2. Single dressings of ammonium sulphate and casein were of similar value at each of three cuttings in 1956.3. Casein treated with formalin released nitrogen much more slowly and was of little value in the early part of the growing season. Formalized casein produced significantly higher yields than casein at the later cuttings in both years, but aggregate increases from this material were much lower than those obtained from untreated casein in each season. Formalized casein increased yields considerably in the year following application.4. Single dressings of formalized casein were also compared with ‘repeated’ dressings of ammonium sulphate, calcium nitrate and urea, in which the same total quantity of nitrogen was divided equally between cuttings. Formalized casein produced much lower yields than these ‘repeated’ dressings in the early part of the season, but was of only slightly less value at the last cut in 1956 and gave the highest yield at the final cut in 1957. Aggregate yields from repeated dressings of inorganic N fertilizers were higher than those given by single dressings of either form of casein.5. Comparisons were also made between the yields given by ammonium sulphate, calcium nitrate and urea. Urea applied before sowing (at 0·5 cwt. N/acre) damaged germination and reduced plant establishment slightly. Under dry conditions both urea and calcium nitrate tended to give higher yields than ammonium sulphate but with adequate rain all three fertilizers gave similar yields.
The skin characters of some breeds of indigenous African cattle
Authors: Walker C. A. 
Published: March 2009

The present work extends the information on the skin thickness of cattle and shows that generalizations made in previous work were only partly correct, for there are significant differences only between the skin thickness of the Zebu ‘races’ of tropical cattle and Bos taurus.Again there appeared to be no significant difference between animals of different ages within breeds.The work confirmed that cattle of eleven tropical breeds comprising four of the major ‘races’ of African indigenous cattle have a significantly thinner papillary layer than temperate breeds, and this was very strongly correlated with their superior heat toleration.Further support based on wider premises was therefore given to suggestions made by Dowling regarding the importance of the histology of the skin in heat toleration.
The population, morphology and evolutionary trends of the apocrine glands of African indigenous cattle
Authors: Walker C. A. 
Published: March 2009

An examination of the population density and morphology of the apocrine glands of four ‘races’ including fourteen breeds of African indigenous cattle has been completed.Two types of gland were found, the club-shaped and the sac-like, and it is suggested that the former is the more primitive form.Considerable differences in gland density and volume were found. In the thoracic-humped African Zebu both of these were similar to figures given for B. indicus sui generis.Gland volume was found to be closely correlated to heat toleration, but it is suggested that secretory rate is probably of high importance in view of the fact that despite differences in gland volume, there were only small differences in heat toleration coefficient.It is suggested that the heat toleration coefficient as presently defined may not be a reliable indication of the animals tolerance of prolonged high temperatures.A suggestion is made regarding the mechanism of heat control by sweating in cattle.
The effect of sulphate of ammonia applications on the sulphur content of various grass and clover mixtures
Authors: Jones D. J. C. 
Published: March 2009

1. The effects of annual applications of 0–12 cwt. per acre of sulphate of ammonia on the herbage levels and yields of sulphate sulphur and total sulphur were investigated in four seeds mixtures 1 year and 4 years after seeding down.2. There were significant increases in the levels and yields of both forms of sulphur up to the 2 or 4 cwt. per acre level of application in both years. The maximum values occurred at the 6 or 8 cwt. level and the corresponding values at the 12 cwt. per acre rate of application declined in many cases.3. The cumulative effects of the annual dressings of sulphate of ammonia resulted in substantial increases of approximately 50% in the levels of sulphate sulphur and total sulphur with much smaller increases in the levels of non-sulphate sulphur.4. Duplicate plots which received 2, 4 and 6 cwt. per acre of sulphate of ammonia also received an additional 2 cwt. per acre immediately after the first cut each year. This splitting of the dressings had no significant effect on the accumulation of sulphur by any seeds mixture. A second cut from the cocksfoot plots in the first year showed the sulphur levels in the plots which received the additional sulphate of ammonia to have increased less than the levels in those which received only the initial dressing. This was explained in terms of the yields of the components.5. There was a tendency for the rye-grass mixture to contain more sulphate than the other mixtures particularly in the fourth year.6. The possible significance of the increases found in sulphate levels in the copper-molybdenum metabolism of grazing animals is discussed.
Studies on the production of beef from zebu cattle in East Africa II. Milk production in suckled cows and its effect on calf growth
Authors: Lampkin K. , Lampkin G. H. 
Published: March 2009

1. The estimation of milk yield in a herd of suckled zebu cattle has been described.2. Milk yield was found to be relatively stable when compared with weight at calving and subsequent live-weight change.3. Under constant conditions, there was a negative correlation between milk yield and live-weight change in the cows, compared with a positive correlation when both characters were affected by seasonal changes.4. Variation in milk yield was reflected in the growth rate of the calves, but considerably greater quantities of milk were required to increase growth without the aid of extra grass.5. It was concluded that, under the present conditions, calf growth rate could be increased more efficiently by the improvement of nutrition than by selection for high milk yield in the dams.
Fission products and the dairy cow III. Transfer of 131iodine to milk following single and daily dosing
Authors: Garner R. J. , Sansom B. F. , Jones H. G. 
Published: March 2009

1. The transfer of 131I to milk has been studied in dairy cows following oral administration of carrierfree material in single doses as sodium iodide or as elementary iodine and in daily doses as sodium iodide.2. The total recovery from milk during the 6 days following administration of a single dose in twentyeight experiments on fifteen animals ranged from 1·3 to 19·4% of the dose with a mean value of 5·5%. The variations in recovery can be attributed largely to differences in the milk yield.3. There was no significant difference in the biological availability of 131I administered as iodide or iodine.4. The change in concentration of 131I in milk with time following daily dosing did not follow the predicted course, a peak value being observed in most animals after 1–3 days, followed by a fall and a subsequent rise to a steady value lower than was expected.5. The presence of a concentrating mechanism in the udder has been demonstrated by administration of sodium thiocyanate. Comparison of the milk total 131I: plasma dialysable 131I ratio at different times of the year indicates that the concentrating ability may be lower in the summer than in the autumn-spring months.
Effect of castration and dietary protein level on growth and carcass composition in beef cattle
Authors: Robertson I. S. , Paver H. , Wilson J. C. 
Published: March 2009

SUMMARYThirty-six Hereford cross Friesian calves weighing on average 82.4 kg at an average age of 90 days were allotted in randomized blocks to a 2 x 3 factorial design. Castration by the open method was performed on half the number of calves and three dietary crude protein levels, 20, 14 and 11 % in dry matter were used in a mainly cereal concentrate diet fed ad libitum individually to the animals in stalls. Slaughter was at a fixed weight of approximately 420 kg.Steers compared with bulls gained weight at a significantly slower rate and with less efficiency. Castration's greatest effect in reducing rate of gain occurred during the later stages of rearing when puberty in the bulls, as measured by a steep rise in seminal fructose, was associated with their relatively well maintained live-weight gain. The influence of testicular hormones was also apparent in the bull's carcass with its heavier head, horn and hide and significantly higher proportion of lean and lower proportion of fat in the side.Dietary protein level affected rate of gain in both bulls and steers but at each level bulls performed better than steers. With circumstances similar to those in this experiment, a 14 % crude protein level in concentrate dry matter appears adequate for both categories up to a live weight of circa 270 kg and a reduction to 11 % thereafter. The effect of protein level on tissue proportions of the side and carcass composition generally was minimal.
Studies on the adaptability of three breeds of sheep to a tropical environment modified by altitude II. Responses in body, skin and coat temperatures, cardio-respiratory frequencies and rate of moisture secretion of ewes to the diurnal fluctuation in ambient temperature during the hottest part of the year
Authors: Symington R. B. 
Published: March 2009

Responses in body, skin and coat temperatures, cardio-respiratory frequencies and rate of moisture secretion of ewes of three breeds to the diurnal fluctuation in ambient temperature were recorded in the presence and absence of drinking water during the hottest part of the Rhodesian year.1. At 7.0 a.m. body temperatures were: Merino 102·8° F.; Persian 102·2° F. and Native 101·5° F. Between 7·0 a.m. and 1·0 p.m. body temperature rose almost equally in Persians and Natives and fell slightly in Merinos. Change in body temperature between 7.0 a.m. and 1.0 p.m. was not affected significantly by availability of water nor age of ewe, but varied with type of thermal burden (i.e. solar insolation only v. solar insolation plus artificial heat) when water was not available. Although air temperature fell towards late afternoon body temperature of Merinos and Natives rose appreciably, that of Persians only slightly.2. At 7·0 a.m. respiratory rates were (cyc./min.): Merino 59·6; Persian 43·0; Native 29·9. Increase in rate of respiration was the main thermolytic mechanism in all breeds. Merinos had a lower threshold of respiratory response to rising ambient temperature than either hair breed but increase in rate of respiration between 7.0 a.m. and 1.0 p.m. did not differ significantly with breed or age.3. No breed appeared to use the peripheral blood system in thermoregulation. Cardio-frequency, as a measure of this blood flow, remained almost constant with a slight tendency to fall with rise in ambient temperature.4. In all breeds skin temperature was related to ambient and body temperatures; consequently the diurnal fluctuation in skin temperature differed in wool and hair breeds. When thermal burden was greatest Merino skin temperature fell, that of hair breeds did not.Except at 11.0 a.m. there was a gradient between rectal, skin and air temperatures. Direct elimination of heat was thus possible for 23 hr. each day.5. In hair breeds moisture secretion depended on insensible perspiration; consequently, rate of moisture secretion changed with body and air temperatures. In Merinos moisture for skin surface evaporation was provided by sensible and insensible perspiration. Natives may be able to sweat at temperatures higher than those recorded but it is unlikely Persians have a sweating mechanism.6. In all breeds coat temperature was related closely to ambient temperature and changes in solar conditions evoked immediate response in coat temperature. Merino fleece apparently stabilized skin temperature whereas Persian and Native hair did not.