bluuebunny/crossref_metadata_2025_split huggingface dataset:
The nutrition of the bacon pig: V. The minimum level of protein intake consistent with quick growth and satisfactory carcass quality
Authors: Woodman H. E. , Evans R. E. 
Published: March 2009

The present investigation is the sequel to an earlier pig-feeding trial in which a diet supplying only half the standard amounts of protein supplement, in the form of a mixture of feeding blood meal, dried separated milk and ex. soya bean meal, was found to give as good results from the standpoints of rate of growth, efficiency of food conversion and carcass leanness and quality, as a diet that contained the full standard allowances.It was considered desirable to repeat this initial exploratory experiment, making use this time of a totally different form of protein supplement, since the question of the biological efficiency of the protein supply might conceivably be of critical importance at the lower levels of protein feeding. In the present trial, therefore, the mixture of the three protein foods was replaced by a single protein food, namely, white fish meal. The standard-protein treatment C supplied 12% of white fish meal up to 90 lb. live-weight, 10% from 90 to 150 lb., whilst from 150 lb. to slaughter at about 200 lb. live-weight, the white fish meal was omitted from the diet, its place being taken by 5% of ex. soya bean meal. The corresponding allowances of protein food in the low-protein treatment B were 5, 4 and 3% respectively. The low-protein treatment A, which was introduced as a link between the previous and the present trials, contained the protein supplement composed of feeding blood meal, dried separated milk and ex. soya bean meal and supplied the same amount of digestible protein as was contained in the low-protein treatment B.
The determination of the size distribution of soil clods and crumbs
Authors: Russell E. W. , Tamhane R. V. 
Published: March 2009

1. It is possible to determine the size distribution of clods in the field by simple sieving of the soil without any pre-treatment provided the soil is not too wet. There is a personal factor involved in the sieving, but with care and training this will not affect comparisons of results obtained by that person. If the soil is too wet the individual clods smaller than 3 mm. stick together on the 3 mm. sieve. This sticking together is first apparent on the 3 mm. sieve but may become appreciable on the ¼ in. (6 mm.) sieve. No certain way was found for overcoming this difficulty.2. There appears to be no best method for determining the size distribution of the soil crumbs, i.e. of the water-stable aggregates in the soil. The method and the technique must be chosen so as to give the maximum amount of useful information. If an appreciable proportion of the crumbs are larger than ½ mm., a water-sieving method is practically essential.3. The method of wetting to be used can only be chosen from a consideration of what information is wanted. If possible it would be desirable for general purposes to use a very slow or a vacuum wetting technique and a very rapid wetting technique such as wetting the soil by immersion in water.4. The decision whether air-dry or field-moist soil should be used depends entirely on the information needed. For general purposes the use of air-dry soil is recommended.
Hormonal augmentation of fertility in sheep: I. Induction of ovulation, superovulation and heat in sheep
Authors: Hammond J. , Hammond J. , Parkes A. S. 
Published: March 2009

1. Gonadotrophic extracts of horse-pituitary gland, of pregnant mare serum and of urine of pregnant women, as well as oestrogenic substances, will induce ovulation in anoestrous sheep. The number of ova shed is apparently independent of the dosage given and lies within the normal range.2. The oestrogens probably act by evoking ovulation-producing activity on the part of the animal's own pituitary gland, and it is likely that the gonadotrophins also initiate the same chain of events by causing oestrogen secretion by the ovary.3. Oestrogens induce heat in the anoestrous sheep, but horse-pituitary extract and P.M.S. evoked sexual receptivity only in animals having a regressing corpus luteum. In the absence of a corpus luteum, ovulation occurs without heat, while the presence of an active corpus luteum usually suppresses both ovulation and heat.4. Administration of horse pituitary a few days before the corpus luteum is due to regress results in superovulation at the succeeding heat, as many as twelve simultaneous ovulations having been obtained under these conditions.
Factors affecting the stability and estimation of carotene in artificially dried grass and hays
Authors: Kon S. K. , Thompson S. Y. 
Published: March 2009

1. The influence of storage in the light and in the dark at ordinary temperature and in a heated room at 70–80° F. on the carotene content of finely ground artificially dried grass stored in paper sacks and jute sacks was studied. There was an initial drop in carotene content from 61·1 to 46·5 mg./100 g., i.e. 23·9%, in the first month, and a total loss of 31·4% during 6 months' storage (August to February). No difference could be detected either between treatments or types of containers.2. There was a marked loss of carotene during 13 months' storage of baled artificially dried grass and of hays, amounting to 30–40% of the original value.3. Two methods of estimating carotene were compared. The method of Ferguson & Bishop (1936) gave higher results than the method of Peterson, Hughes & Freéman (1937). The difference is probably due to incomplete extraction in the latter method.4. Chromatographic analyses of “carotene” fractions from the above grasses showed the presence of coloured impurities amounting to 20·5–33·8% of the total recovered pigments.5. As these impurities are biologically inactive, chromatographic analysis or the use of special solvents are probably necessary for the accurate determination of carotene in forage.
Preliminary experiments on the estimation of traces of heteroauxin in soils
Authors: Parker-Rhodes A. F. 
Published: March 2009

A method is described by which small quantities of indolyl acetic acid can be detected and measured quantitatively, depending on the effect of this substance on osmotic pressure of root hair cells of wheat seedlings. Full details are given of the procedure adopted and the precautions which it was found necessary to take, and suggestions are put forward as to how the method might be rendered more accurate if necessary. Possible sources of e"rror are also discussed.An experiment is described in which this method is used to determine what effect is produced by different manurial treatments on the content of indolyl acetic acid in the soil. It was found that farmyard manure tended to increase the quantity present.
Lattice squares
Authors: Yates F. 
Published: March 2009

A new method of analysing the results of experiments arranged in lattice (quasi-Latin) square designs is described. By this method the information contained in the inter-row and inter-column comparisons is recovered. The procedure followed is to estimate the actual accuracy of the inter-row and inter-column comparisons relative to intra-row and column comparisons, and assign weights proportional to these relative accuracies.The methods of computation by which this procedure can be carried out expeditiously are described in detail, and are illustrated by two experiments carried out at Rothamsted and Woburn. The gains in accuracy obtained in these two experiments (as compared with ordinary randomized blocks) were approximately 30% and 60% respectively, allowing for losses of information due to inaccuracies of weighting.
The teart pastures of Somerset: II. Relation between soil and teartness
Authors: Lewis A. H. 
Published: March 2009

1. Teart soils contain molybdenum in amounts varying from about 0·002 to 0·010% in the surface horizon and are neutral or alkaline in reaction and often calcareous. The contents of molybdenum increase down the soil profile. Teart soils are developed from Lower Liassic materials, but all soils formed from the Lower Lias are not teart. Those which are acid in reaction in the surface horizons are not teart even if their molybdenum content is high. Others which contain little molybdenum are also not teart; such soils cover a large area in Glamorgan.2. Molybdenum appears to be concentrated in the (uppermost) argillaceous component of the Lower Lias. The limestone contains little molybdenum. The soils of Somerset are largely derived from the upper, argillaceous component while those of Glamorgan are largely derived from the lower, limestone component. This may explain why the soils of Somerset contain much more molybdenum than those of Glamorgan.3. Somerset soils formed from Keuper, Middle Lias, Upper Lias and Cretaceous material generally contain little molybdenum and are not teart.4. How a knowledge of the relation between soil and teartness can be turned to practical advantage is briefly discussed.
Milk-fed calves:4. The effect of herbage allowance and milk intake upon herbage intake and performance of grazing calves
Authors: Baker R. D. , Barker J. M. 
Published: March 2009

SUMMARYThe effect of herbage allowance and milk intake upon herbage intake and performance was investigated using 48 Hereford × Friesian calves purchased at 10–12 days of age and reared on reconstituted milk substitute. Groups of 24 calves were fed low (L) or high (H) daily quantities of milk normally associated with 240-day lactation yields of 1000 or 2000 kg. Six calves on each milk treatment were allocated to four daily herbage allowances during the grazing season. These were 20, 40, 60 or 80 g/kg herbage dry matter/kg live weight.There was no effect of herbage allowance before day 95; thereafter both herbage intake and live-weight gain of the L20 and H20 groups were depressed. The effect was greatest for the L calves. Additional milk consumption reduced herbage intake at all herbage allowances. Milk intake influenced the extent to which calves were buffered from the effects of a low herbage allowance.
The estimation of the nutritive value of feeds as energy sources for ruminants and the derivation of feeding systems
Authors: Blaxter K. L. , Boyne A. W. 
Published: March 2009

SUMMARYThe results of 80 calorimetric experiments with sheep and cattle, mostly conducted in Scotland, were analysed using a generalization of the Mitscherlich equation R = B(l–exp(–pG))–l, where R is daily energy retention and G daily gross energy intake, both scaled by dividing by the fasting metabolism. The relations between gross energy and metabolizable energy were also examined. Methods of fitting the Mitscherlich equation and the errors associated with it are presented.It is shown that the gross energy of the organic matter of feed can be estimated from proximate principles with an error of ±2·3% (coefficient of variation) and that provided different classes of feed are distinguished, the metabolizable energy of organic matter can be estimated from gross energy and crude fibre content with an error of ±6·9%. Parameters of the primary equation made with cattle agreed with those made with sheep and there was no evidence of non-proportionality of responses on substitution of feeds in mixtures.The efficiency of utilization of gross energy for maintenance and for body gain of energy was related to the metabolizability of gross energy and, in addition, to fibre or to protein content. Prediction equations are presented which describe these relationships.It is shown that the primary equation can be manipulated to express a number of biological concepts and that its two parameters B and p can be simply derived from estimates of the two efficiency terms for maintenance and production.The results are discussed in relation to the design of feeding systems for ruminant animals and to the derivation of optima in their feeding.
The respiration rate and loss of dry matter from stored bran
Authors: Snow Douglas , Wright Norman C. 
Published: March 2009

1. Experiments were made on the respiration of bran at different moisture levels using a continuous absorption apparatus in which the humidity of the air-stream was adjusted to be at equilibrium with the respiring bran. The rate of respiration was accelerated with increasing moisture content and was very rapid deterioration due to the high respiration rate and microbiological damage.2. Experiments were made on the storage of bran at known moisture contents in closed tins in the laboratory and also in sacks kept under farm conditions. The total nitrogen content of the bran stored in the tins appeared to increase during storage. From similar increases in total phosphorus, it is clear that the increase in total nitrogen was caused by a loss of dry matter from the stored feeding stuff, a fact which was further demonstrated by the loss in dry weight of the sacks of bran with attributed to two causes: (1) the respiration of the plant cells still active in the bran itself, and (2) the respiration of developing micro-organisms. It is evident from these experiments that fresh bran, free from insect infestation and stored at a moisture content of less than 13%, will have a very low respiration rate and will, therefore, not be liable to heating. Bran of 15–19% moisture content respires at a much faster rate and the time for which such material can be stored with freedom from heating or other types of deterioration will be limited.
Lactation in heifers induced by oestrogen implants
Authors: Day F. T. , Hammond J. 
Published: March 2009

Average lactation curves have been prepared from selected animals in a group of heifers treated for 60 or 100 days with stilboestrol or hexoestrol tablet implants. A treatment period of 100 days appears to give poorer results than one of 60 days. The optimum duration, on the average, is probably about 75 days, but seems to depend upon the way lactation develops—which bears no obvious relationship to the amount of oestrogen absorbed.A rise in yield follows tablet removal whether this is done while the yield is still rising or after it has begun to decline. Yield in an induced lactation may fall very far short of the animal's inherent capacity, but comparison between induced lactations and those at subsequent calvings shows that it may very nearly approach what would be a normal yield.A heifer which was treated twice did rather less well in her second induced lactation.Breeding histories of a number of implanted heifers are outlined. They were all animals which had failed previously to get in calf. 5–10% (without further treatment) did not return to an ovulatory cycle. About 70% of anatomically normal heifers got in calf, the service rate being about 2·6. A rather high incidence of abortions may be a feature of a recovery period from treatment, but may have been due to selection of animals with such a tendency.
Seasonal variation in the reproductive capacity of the bull
Authors: Anderson J. 
Published: March 2009

Seasonal variation in the reproductive capacity of the bull was studied during a 27-month experimental period at the Experimental Station. There are a total of 1049 ejaculates for this period. Supplementary data for other periods on the Experimental Station and for two other large farms practising artificial insemination are also included.Highly significant individual and monthly differences were noted during the experimental period for the density and motility of the sperm, the pH of the semen and for the percentage of ejaculations performed. The seasonal variation in semen is marked, but there is considerable variation in different years between bulls and between farms in the periods of maximal and minimal types of semen and in seasonal trends.The relationship between such variation and climatic and nutritional conditions is discussed. There appears to be a basic seasonal rhythm in bull semen associated with climatic factors, warmer conditions causing stimulation and vice versa. Nutritional factors may, however, modify this rhythm. The relationship between seasonal variations in semen quality and fertility is discussed.
Studies on the behaviour of cattle and sheep in relation to the utilization of grass
Authors: Hughes G. Pearson , Reid D. 
Published: March 2009

The importance of conducting studies on the behaviour of grazing animals has been stressed by several authors. Stapledon & Jones (1927) indicated the need for such work; while more recently Stapledon (1948, 1949) has made further reference to this need.Adequate reviews of the work conducted prior to 1939 are to be found elsewhere (Castle, Foot & Halley, 1950; Tribe, 1950), and only the more important aspects need be considered here. The main weakness on the part of many of these earlier studies was that they were based on few observation periods, and that few animals were observed during each period. Many workers (Cory, 1927; Hodgson, 1933; Sheppard, 1921) carried out their observations during the daytime only, on the assumption that little or no grazing occurred after dark. In spite of this and the fact that the methods of study adopted varied considerably, some correlation exists between the results reported by the different workers.
The carbonic anhydrase activity of the hen's oviduct
Authors: Common R. H. 
Published: March 2009

1. Some preliminary observations on the carbonic anhydrase activity of the hen's oviduct are reported.2. It is suggested that the carbonic anhydrase activity of the uterine epithelium is higher than that of the remaining oviducal tissues, and that this activity may play a part in shell secretion.
An investigation of nitrogen uptake in mixed crops not receiving nitrogenous manure
Authors: Nowotnówna Anna 
Published: March 2009

1. The total yield of dry matter of rye-grass, grown in the presence of inoculated (a) peas, (b) red clover, (c) serradella, in sand with no added nitrogen, after 13 weeks' growth was increased by about three times in the peas-rye-grass series, twice in the clover-rye grass series, and nearly twice in the serradella series in comparison with the yield of rye-grass grown alone.2. The nitrogen percentage and total nitrogen yield of rye-grass were greatly influenced by associated growth with peas, clover or serradella. Rye grass grown with peas after 13 weeks' growth contained nearly five times, grown with clover three times, grown with serradella about twice, as much total nitrogen, as grass of the same age similarly grown, but in the absence of leguminous plants.3. Among the three leguminous species tested at Pulawy, peas were the best companions for rye-grass, giving the highest amount of assimilated nitrogen, while serradella gave the smallest.4. In another experiment, when barley and (a) peas, (b) red clover, (c) lucerne were grown together in sand without added nitrogen, only peas exerted a beneficial influence upon the yield of dry matter and the nitrogen percentage and total nitrogen yield of barley.
Base exchange equilibria in soil profiles
Authors: Mitchell R. L. 
Published: March 2009

1. The conditions governing base exchange equilibria in soil profiles are discussed.2. Exchangeable cation contents of six profiles are reported, the results including figures for Ca, Sr, Mg, Na, K, H and exchange capacity, as well as clay content and pH value.3. It is shown that cation displacement occurs as a result of the downward movement of hydrogen ions from the surface layers, and a layer of minimal basic cation content exists at about 30 cm. depth.4. Below this depth the basic cation content increases once again, but the base exchange capacity follows the clay content fairly closely.5. Calcium and strontium are displaced (and readsorbed) at similar rates, in accordance with their exchange constants, although there is about 400 times as much calcium as strontium present. The behaviour of the other cations also appears to be in accordance with theoretical demands.
The nutrition of the bacon pig: II. The influence of high-protein intake on protein and mineral metabolism
Authors: Woodman H. E. , Evans R. E. , Turpitt W. G. 
Published: March 2009

An investigation has been made, by the method of balance trials, of the utilization of food protein, at different levels of protein intake, by bacon pigs throughout the period of growth from weaning to slaughter. Information has also been secured relating to the retention of lime, phosphoric acid and chlorine. The main conclusions are as follows:(1) The young pigs after weaning were able to digest their food with as high an efficiency as was displayed in the later stages of growth. The extra protein in the high-protein rations had little or no effect on the extent to which the food was digested.(2) No evidence was secured at any stage of the trials suggesting the presence of protein in the urine of the pigs subsisting on the high-protein diet.(3) The gilts showed a consistently higher rate of nitrogen retention than their brother-hogs. This behaviour was manifested even when the protein supply in the gilt's ration was lower than that in the ration of the hog with which it was compared. This more efficient utilization of food protein by the gilts is held to explain the tendency of gilts to give somewhat leaner carcasses than hogs.(4) Nitrogen retention from the high-protein diet was no higher than from the normal-protein diet, a rinding suggesting that the amount of protein in the normal rations is sufficient to meet the demands for the quick growth required by modern standards of bacon production.
Fertility, morality, and growth rate in pigs
Authors: Menzies-Kitchin A. W. 
Published: March 2009

1. Large White sows are more prolific than Large Black sows, but mortality up to 6 weeks is higher in the former breed. At 6 weeks, litters from both breeds contain practically the same number of pigs. At that age, however, pure-bred Large White pigs appear to be slightly heavier than those of the Large White/Large Black cross.2. Sows show no significant deterioration in litter size or in litter weight at 6 weeks up to the tenth litter, but percentage death-rate tends to increase with farrow number.3. There appears to be little advantage in producing litters with more than 12 pigs at birth. In litters containing more than 12 pigs the addition in number is more than off-set by an increase in death-rate.4. There is no significant difference at 6 weeks between the average weights of pigs from litters of different size at birth. There is, however, a difference in average weight according to the number of pigs surviving at 6 weeks; the larger the number the lighter the pigs.5. The season in which the sow farrows appears to exercise a considerable influence on survival rate at 6 weeks; approximately one pig more per litter surviving in the summer than in the winter months.6. There is a definite negative correlation between the weight of the pigs at 6 weeks and the age at which they reach bacon weight. But the rate of post-weaning growth of the heavy pig is not necessarily greater than that of the light pig.7. Post-weaning mortality appears to increase with increase in litter variation.8. Litters which are fattened during winter months take longer to reach bacon weight than those fattened during summer.9. Rapid growth rate and high grading results are not incompatible when the conditions of suitable rations, good stock, and proper management are observed.10. The third and fourth week of age appears to be a critical stage in the life of the suckling pig, and especial care must be exercised in its treatment at that period.