bluuebunny/crossref_metadata_2025 huggingface dataset:
An analysis of growth of different cattle genotypes reared in different environments
Authors: Frisch J. E. , Vercoe T. E.
Published: March 2009

Calves from three breeds, Brahman, Hereford × Shorthorn (HS) and Brahman × HS (BX), were divided equally into two groups, one of which was treated every 3 weeks from birth onwards to control ticks and gastrointestinal helminths, and one of which was untreated. Mortalities, growth rates and levels of resistance to environmental stresses that affected both mortality and growth under grazing conditions were recorded for all animals up to weaning (6 months) and for all males up to 15 months of age. The Brahmans were the most and the HS were the least resistant to environmental stresses, each of which was shown to depress growth in proportion to its magnitude and to contribute to the high mortalities of the HS. All breeds responded positively to parasite control with the greatest response in both survival and growth in the HS breed and the least response in the Brahman breed.

Samples of males from the various breed-treatment groups were taken into pens where they were protected from environmental stresses and fed both low-quality pasture hay and high-quality lucerne hay ad libitum. Measurements were made of fasting metabolism, maintenance requirement, voluntary food intake and gain, variables related to the growth potential of each animal. The HS animals had the highest whilst the Brahmans had the lowest values for each variable.

However, despite their low growth potential, the Brahmans had the highest growtli rate, and the HS, despite their high growth potential, had the lowest growth rate, when growth was measured in the presence of all environmental stresses. When parasites were controlled, growth rates were highest for the BX, the breed with intermediate growtli potential, and did not differ between the HS and Brahmans. These interactions arose because of the different contributions of resistance to environmental stresses and growth potential to growth rate measured at the different levels of environmental stresses. The relevance of these interactions to breed evaluation and cross-breeding is considered.

Growth potential and resistance to environmental stresses were negatively correlated both between and within breeds, though the latter was biased by the effects of compensation. The influence of these relationships on the likely outcome of selection for increased growth rate, both between and within breeds, is discussed.
Effect of spacing on growth and yield of sunflower (Helianthus annuus L.) under two systems of dry farming in Sudan
Authors: Khalifa F. M.
Published: March 2009

An experiment was conducted over a 2-year period at two sites in the central rainlands of Sudan under rainfed conditions at one location and under supplementary irrigation at the other to investigate the effects of cultivars and spacing on yield and yield components of sunflower. Row spacing had no significant effect on grain yield under either system of production. Under rainfed conditions, the late maturing cultivar Manchurian performed better under wider row spacing than Hungarian-A which is a medium late maturing variety. Size and number of seeds weie significantly affected by row width. It is argued that the choice of a row spacing for sunflower production on a commercial scale in dry regions should be evaluated in association with machine efficiency which is affected by plant height, stem circumference, head diameter and lodging, all of which were significantly affected by row width. Also the number of plants established per unit area of land differed between systems of farming.
The nutritive value of normal and brown midrib-3 maize
Authors: Weller R. F. , Phipps R. H. , Griffith E. S.
Published: March 2009

Normal and brown midrib-3 (bm3) maize plants of three genotypes (Inra 188, Inra 240 and Inra 258) were sampled at three stages of maturity. Whole crop and plant components were analysed for in vitro digestible organic matter in the dry matter (DOMD) and the concentration of neutral detergent fibre, cellulose, hemicellulose, xylose, soluble sugars, starch and total nitrogen in the dry matter.

The concentrations of total nitrogen, neutral detergent fibre, cellulose, hemicellulose and xylose were similar in both normal and bm3 plants. Xylose was the main constituent sugar of hemicellulose forming 70–75% of the total hemicellulose. The higher concentration of soluble sugars and lower concentration of starch in the bm3 plants was attributed to the later maturity of the bm3 plants.

The bm3 gene significantly reduced lignin synthesis in the whole plant and plant components at all harvests. The mean concentration of lignin in the normal and bm3 plants were 2·2 and 1·4%, respectively. The ferulic and p-coumaric acid concentrations in the bm3 plants were 1·31 and 0·93 mg/g D.M. compared with 1·59 and 1·16 mg/g D.M. for the normal plants, respectively.

The in vitro DOMD values for the bm3 plants were significantly higher (P < 0.05) than their normal counterparts.
The redistribution of a surface layer of solute during the drainage of a soil profile to field capacity
Authors: Towner G. D.
Published: March 2009

An approximate analytical method derived by Wilson & Gelhar (1981) is a powerful and flexible one for calculating solute distribution profiles developing under steady state and transient water flow conditions. Solute concentration profiles developing from an initial deposition in the surface layer, as the soil profile returns to field capacity, have been calculated using the method for idealized representations of the two principal forms of water redistribution.

The profiles depend very strongly on the mode of redistribution of the water. However, the small spread of the final profiles (at field capacity) across the range of water redistribution types examined suggest that, for agricultural application, it might be accurate enough to use a simplified representation of the actual redistribution rather than the correct, and inevitably more complicated, water flows and distribution.
Physiological analysis of growth and yield variation of rapeseed and mustard
Authors: Chauhan Y. S. , Bhargava S. C.
Published: March 2009

Rapeseed and mustard crops are the second most important source of edible oil after groundnut in India. The average yield of these crops is around 600 kg/ha which has been static for several years. These low yields are of increasing concern in view of the short supply of oil seeds in India. Considerable breeding efforts are being directed to improving production potential as well as stability of yield in these crops (Prakash, 1980). An understanding of the physiological basis of yield formation can be of great help in selecting for high and stable yields. However, there is little information available on the production physiology of these crops (Mehrotra, Saxena & Moosa, 1976; Bhargava & Tomar, 1982).
Effect of grazing simulation on forage hay and grain yields of spring barleys in a low rainfall environment
Authors: Droushiotis D. N.
Published: March 2009

A 4–year experiment was conducted at two sites in each year to evaluate some of the effects of five harvesting treatments on the forage and grain production and quality of four spring barleys sown in November and grown under rainfed conditions. A single harvest during the growing season at the milk stage of grain produced the highest herbage drymatter and digestible yields.One harvest at tillering reduced significantly the plant height, grain production and dry-matter yields of straw and hay, while the digestibility of the organic matter in the dry matter (D-value) and the crude-protein content of straw, crudeprotein content of grain and the number of tillers were not affected. The weighted mean of D-value and crude-protein content of herbage was increased when a ‘grazing’ cut was taken prior to harvest. In addition lodging was eliminated. Three or four harvests during the growing season resulted in very low forage yields of otherwise excellent quality.
Assessment of dry-matter yield from grain yield in the West African Savannah Zone
Authors: Powell J. M.
Published: March 2009

Crop residues, consisting of cereal stovers and hays made from the vegetative parts of grain legumes, are important dry-season feeds for ruminant livestock in the Savannah Zone of West Africa (van Raay, 1975; McCown, Haaland & de Haan, 1979; Jahnke, 1982). With the increasing demand on land to produce more crops and animal products, traditional systems are under pressure. There is need for a reliable means to quantify the supply of feed from various sources and to monitor the type, quantity and quality of crop residue available to livestock.
The effect of sulphur on the yield and chemical composition of winter barley
Authors: Scott N. M. , Dyson P. W. , Ross J. , Sharp G. S.
Published: March 2009

The changeover from fertilizers containing calcium or ammonium sulphate to those containing little or no sulphur has led to the occurrence of sulphur deficiency in many areas of the world (McNaught & Christoffels, 1961). In the United Kingdom, it was thought that even in the absence of fertilizer sulphur, atmospheric inputs were sufficient to ensure an adequate supply for crops. Recent work in the north of Scotland has shown that this is not so, that many soils in the area are low in sulphur, and yield responses have been obtained following application of sulphur to grass (Soott et al. 1983; Scott, 1984). The purpose of the present experiments was to extend the work to cereals, in particular to examine the response to added sulphur of the grain yield of winter barley, and to measure the effect of sulphur on the chemical composition of plants.
Effects of chronic environmental heat stress on blood flow and nutrient uptake of the gravid bovine uterus and foetus
Authors: Reynolds L. P. , Ferrell C. L. , Nienaber J. A. , Ford S. P.
Published: March 2009

To evaluate the effects of chronic environmental heat stress during mid-gestation on gravid uterine and foetal metabolism, mature Hereford cows were assigned to control (n= 8) or heat stress (n= 5) treatments beginning on day 100 of gestation. Uterine and umbilical blood flows were estimated by the steady-state diffusion procedure on day 169 ± 4 of gestation. Oxygen (O2), glucose, lactate, α-amino nitrogen and urea nitrogen concentrations were determined for uterine and umbilical blood samples collected during this procedure. Foetuses and foetal fluids were collected on day 174±4.

Uterine and umbilical blood flows were reduced and foetal weight also was less for heat-stressed than for control cows. In addition, foetal liver weight as a proportion of foetal weight and total foetal liver RNA and protein were less for heat-stressed cows. Uterine and umbilical arterial–venous concentration differences in metabolites were similar between the two groups. Uterine, foetal and utero-placental uptake or secretion rates of the metabolites measured in this study were reduced in the heat-stressed cows, primarily because of differences in blood flow. Thus, chronic heat stress during mid-gestation had an adverse effect on foetal development resulting, at least in part, from decreased uterine and umbilical blood flows, which led to a reduction in uterine, utero-placental and foetal nutrient uptake or secretion rates.
The cellulase content of 15 species of entodiniomorphid protozoa, mixed bacteria and plant debris isolated from the ovine rumen
Authors: Coleman G. S.
Published: March 2009

The cellulolytic activity of cell-free extracts of 15 species of entodiniomorphid protozoa grownin vitroand under two conditionsin vitrohas been measured using six different assays with substrates varying in complexity from carboxymethylcellulose to microcrystalline cellulose. Although there were differences between the assays, the highest activities were found inEudiplodinium maggii, Epidinium ecaudatum caudatumandOstracodinium obtusum bilobumwith little or no activity in fiveEntodiniumspp. There was no consistent effect of growth conditions on cellulase content although with protozoa grownin vitrothose grown on grass alone tended to contain more cellulase than those grown on starch and grass.

A survey of methods for the release of cellulase from other rumen fractions was made and mild treatment with ultrasound of the fraction suspended in water gave the maximal release of enzyme with the highest specific activity. Using this method 62% of the total rumen cellulase was found in the protozoal fraction and 27% was associated with the plant debris in a normal sheep, fed on hay and oats, with an A-type protozoal population.
Use of cluster analysis for classification of Benchmark soil samples from India in different micronutrient availability groups
Authors: Katyal J. C. , Doshi S. P. , Malhotra P. K.
Published: March 2009

In view of the increase in micronutrient deficiencies in crop plants, ans attempt is made to group 57 Benchmark Indian soils into different micronutrient availability classes (clusters) vis-à-vis some soil characteristics. Since most of the soil characters are expressed in proportions or percentages (a usual practice in soil studies), the data matrix was transformed into log10 values to bring it nearer to normality. The transformed data matrix was used for cluster analysis and subsequently also for discriminant analysis. By following the method of Euclidean cluster analysis, the 57 Benchmark soils could be subdivided into three clusters. The distinctness of clusters was proven by distance-matrix as well as discriminant analysis. All the soils of cluster I and II originated from arid and semi-arid climates and these were alkaline in reaction, low in organic carbon (OC) and high in total lime. On the contrary, cluster III comprised all but a few soils from humid-subhumid regions. These soils were acidic in reaction and relatively high in OC and total lime. The soils of cluster I and II were poorer in diethylene triamine penta-acetic acid (DTPA) extractable micronutrient cations than those of cluster III. This study thus reveals that it is possible to classify diverse soils by statistical means into distinct clusters based upon micronutrient availability and associated soil properties. Furthermore, it suggests that soils of arid and semi-arid climates as a group, because of their low micronutrient availability, are expected to be more prone to deficiencies than those of humid and subhumid zones.
Relationship between milk intensity and pituitary-thyroid function in water buffaloes
Authors: Hassan G. A. , El-Nouty F. D. , Salem M. H.
Published: March 2009

Water buffaloes (Bubalus bubalis) are reared in many tropical and subtropical countries for meat and milk production and to serve as draught animals. The improvement of milk yield in water buffaloes has been handicapped by the absence of physiological data that may provide means of rapid genetic improvement. Endocrine function is known to vary with lactation intensity. Thyroid hormones seem to have a stimulatory effect on the metabolic rate and, consequently, on the productivity of dairy animals (Lenon & Mixner, 1957; Picha, Pichova & Karasek, 1970; Swanson, 1972). Anderson (1969) also reported an increase in thyroid activity in lactating cows and rats, although other investigators (Johnson & Vanjonack, 1976; Hart et al. 1978; Hart, Bines & Morant, 1979) reported that lactation induced a decline in plasma thyroid hormones. None of these studies performed measurement of plasma thyroid stimulating hormone.
Effect of urea and neem cake coated urea on yield, and concentration and quality of essential oil in Java citronella (Cymbopogon winterianus Jowitt)
Authors: Prakasa Rao E. V. S. , Singh M. , Ganesha Rao R. S. , Ramesh S.
Published: March 2009

Java citronella (Cymbopogon winterianus Jowitt) is an important perennial aromatic grass cultivated in different parts of India. The steam-volatile essential oil from the citronella herb is widely used in perfumery, in manufacture of deodorants and mosquito repellent creams and in flavouring beverages. Systematic cultivation of this crop is being taken up and application of large quantities of N fertilizers was found to increase yield (Narayana et al. 1975; Bommegowda, 1978; Singh, Pathak & Bodoloi, 1980; Prakasa Rao et al. 1983). However, the efficiency of N utilization by this crop was found to be quite poor (Prakasa Rao et al. 1983). No systematic data are available in India on the effect of harvest season and N fertilizers on the principal constituents of citronella oil. Therefore the present experiment was made with two objectives: (i) to determine the effect of harvest season and N fertilizers on the essential oil concentration and the principal constituents of the oil which determine the oil quality, and (ii) to determine the effect of neem cake, an indigenous cheap material which is reported to have nitrification inhibitory properties, on the herb and essential oil yields of citronella.
Responses of yield, components of yield and nutrient contents of cow pea to magnesium fertilizer in a tropical rainforest region
Authors: Kayode G. O.
Published: March 2009

Field experiments were carried out in the early and late growing seasons in the rainforest zone of Nigeria to determine the responses of yield, components of yield and nutrient contents of cow pea to magnesium fertilizer. Yield and components of yield studied were not significantly increased by Mg application but N, P and Zn concentrations were significantly increased, while Mn concentration decreased significantly with applied Mg.

Yield was positively correlated with the micronutrient (Zn, Fe, Cu, Mn) concentrations of cow pea. A level of 0·43 m-equiv/100 g of exchangeable Mg or 15% Mg saturation appears adequate for successful cow-pea production in a typical forest zone within the humid tropics.
Effects of white clover and fertilizer nitrogen on clover and grass leaf dimensions, percentage cover and numbers of leaves and tillers
Authors: Hollington P. A. , Wilman D.
Published: March 2009

Effects of seven levels of N application and three seeds mixtures were studied on two sites for 4 years. One seeds mixture comprised perennial ryegrass (Lolium perenne L.) and two comprised perennial ryegrass with white olover (Trifolium repens L.). One site (Trefloyne) was 24 m above sea level on deep soil and the other (Pwllpeiran) was 328 m above sea level on relatively shallow soil. The plots were cut seven times per year.

The application of N to swards without clover considerably increased the number of ryegrass tillers as well as increasing ryegrass leaf blade length and width and sheath length. At Trefloyne the presence of clover greatly reduced the number of ryegrass tillers, had a greater positive effect on grass sheath length, relative to its effect on blade length and width, than that obtained by applying fertilizer N to a sward without clover, and tended to reduce grass leaf length during the winter. At Pwllpeiran the clover was less competitive, but it still tended to have a greater effect on sheath length and a less positive effect on numbers of tillers, relative to its effect on blade length and width, than that obtained by applying fertilizer N to a sward without clover. The application of N to grassolover swards increased the size of grass leaves and the number of tillers, but did not increase clover leaflet size. The number of olover leaves in the sward was greatly reduced by fertilizer N at Pwllpeiran, but was not affected by fertilizer N at Trefloyne. Blanca white clover had larger leaves than Aberystwyth S.100, but S.100 appeared to compensate for this by producing rather more leaves. In respect of number of leaves, leaf dimensions and rate of leaf emergence, clover appeared more sensitive than ryegrass to the differences between the sites. The leaf dimensions of the clover varied more from one time of year to another, but not from one year to another, than those of the ryegrass. The number of leaves per unit area of ground varied more in clover than in grass from year to year and from one time of year to another. The rate of emergence of leaves was faster in clover (per marked stolon tip) than in grass (per tiller).
Fleece development and wool growth on the Romney lamb
Authors: Henderson A. E.
Published: March 2009

The extent to which early environment affects wool production of Romney sheep was studied by means of measurement of skin growth, and of fibre numbers and dimensions, of lambs reared to 52 weeks on contrasting planes of nutrition.

Measurement of skin growth revealed a series of gradients which generally conformed with growth and development principles. A great degree of individuality among animals in skin growth on various regions was expressed, and it was not possible to prove that plane of nutrition caused differential skin growth among regions.

An initial low plane of nutrition had a retarding effect on fleece development and fibre growth, but it could not be decided whether there was a permanent effect on fibre numbers. It seems that this is of little practical importance, since a low plane of nutrition during the major part of the follicle development phase does not appear to impair subsequent unit area production, providing immediate nutrition is good.

Examination of fibre attributes, and quantitative fibre growth characteristics on various regions of the body, showed a series of orderly gradients. Large differences existed between the body regions for quantitative production per unit area and this suggests a widely differing nutrient supply of various skin regions.

The importance of immediate nutrition is emphasized. It appears that permanent effects of early environment on future productivity take the form of a lesser area on which wool is produced. The efficiency of the processes, apparently, is not affected.
The importance of vitamin B12for pig feeding
Authors: Dammers J.
Published: March 2009

After it had become evident that vitamin B12can be considered as a part of the so-called ‘Animal Protein Factor’, several experiments with young fattening pigs have been carried out in the Netherlands. The purpose of these experiments was to gain experience as to the value of products rich in vitamin B12for pig feeding. In these trials 312 animals were used.

The results can be summarized as follows:

1. Substitution to a large extent of animal protein by vegetable protein in rations containing tho same total percentage of protein resulted in a retardation of growth.

2. Addition of vitamin B12supplements to feed mixtures low in animal protein in this series of experiments generally gave better results than could be obtained without this addition. In the majority of cases, however, the results did not equal those of the groups which received rations containing the usual amount of animal protein.

3. Vitamin B12can be considered as a component of the animal protein factor, but besides this there probably exist other factors which contribute to the special value of animal protein for young pigs.

4. In circumstances such as prevail in the Netherlands, little benefit can be derived for pig fattening from the use of products rich in vitamin B12.
The effect of decreasing acidity on the solubility of calcium, magnesium and phosphorus in bran and certain pure salt solutions
Authors: Hill R. , Tyler C.
Published: March 2009

1. The precipitation of calcium, magnesium, phytate phosphorus, and non-phytate (chiefly phosphate) phosphorus has been determined in ‘hydrolysed’ and ‘unhydrolysed’ bran, with varying amounts of added calcium as calcium carbonate.

2. It was found that calcium phytate was precipitated before non-phytate (chiefly phosphate), whatever level of calcium carbonate was added.

3. Precipitation began and was more complete under more acid conditions when calcium and Ca: P ratio were high.

4. Similar experiments have been carried out using salt solutions containing calcium and phytate, calcium and phosphate, and calcium, phytate, and phosphate. The results were similar in most cases to those of corresponding bran mixtures.

5. The above results have been considered in relation to the precipitations which are likely to occur in the small intestine, and the possible effects of these precipitations on absorption are discussed.
Some further observations upon pigs reared in cold pens
Authors: Lucas I. A. M.
Published: March 2009

The experiment reported here involved thirty-two pigs from birth to bacon weight. During the 9 weeks before weaning sixteen pigs were reared on damp cold floors in a cold building and sixteen were reared on dry cold floors in the same building. After weaning all the floors were kept dry.

Before weaning four out of the sixteen pigs in each treatment died, but only one, which was in the wet cold floor group, was suspected of having a liver disease which has been described by Naftalin & Howie (1949). A greater incidence of this disease was expected to occur under the cold environmental conditions of the experiment.

After weaning one deformed pig was killed and three other pigs were killed at 40 weeks old. The latter three all had the liver disease. There was evidence that the disease had developed after the pigs were weaned and this indicated that it cannot necessarily be prevented by the provision of dry conditions in a cold house. The growth curves of two of the three pigs fitted the hypothesis that the disease is associated with cold environmental conditions, but the growth curve of the third suggested that it might have contracted the disease during the summer when the minimum air temperature was 54° F.

The possibility was discussed that the liver disease is caused by a virus or low nutritional status interacting with the effects of cold environmental conditions.

The two pre-weaning treatments had no dissimilar effects upon the piglets' weaning weights, blood haemoglobin levels and appetites for solid food, nor did they have any differential effect upon the growth rates and efficiencies of conversion of food to flesh of the pigs which survived to bacon weight. The bacon carcasses from the pigs born and reared to weaning on wet cold floors were shorter and fatter than those from pigs born and reared on dry cold floors. No explanation could be offered for this difference in carcass conformation.

The rates of heat loss from a constant temperature water-bath to an uninsulated concrete floor upon which pigs had not lain were halved by the provision of ½ in. depth of chopped straw bedding. They were also halved if the measurements were taken after pigs had recently been lying on the bare floor, and under these circumstances the provision of ½ in. depth of chopped straw bedding cut the heat losses even further.
Extracted herbage leaf protein for poultry feeding III. The digestibility of the residual product resulting from the extraction of herbage leaf protein
Authors: Hughes G. Pearson , Eyles Dudley E.
Published: March 2009

1. A digestibility trial is described using sheep fed on the product remaining after herbage leaf-protein extraction.

2. The material gave an analysis of 25.7% dry matter, 16.2% crude protein, 0.26% phosphorus, 1.26% potassium and 1.13% calcium.

3. The animals showed no loss in body weight during the feeding period.

4. The material was of low palatability, and the sheep consumed a maximum of 2½ lb. of dry matter per head daily.

5. The average digestibility coefficient of the dry matter was 52.1% and that of the crude protein 67.6%.

6. Nitrogen balance determinations indicated a sufficiency of protein in the feed.

7. The material barely supplied sufficient potassium and was inadequate in its supply of phosphorus and calcium.
The nutrition of maize in sand culture I. The balance of nutrition with particular reference to the level of supply of nitrogen and phosphorus
Authors: Glover J.
Published: March 2009

As part of the overall programme of research directed towards an understanding of fertilizer needs of crop plants in East Africa a study of the nutrition of maize in sand culture has been made.

The purpose of the work was to study growth and yield in relation to changes in the proportion and concentration of the major nutrients, nitrogen, phosphorus and potassium, and if possible to relate the results to the field behaviour of the crop in fertilizer trials conducted by another section of this organization. Simultaneously studies of the uptake of nitrogen and phosphorus were also undertaken. These latter are discussed in the second paper of this series.

This first paper deals only with growth, yield and nutrient content in relation to the nitrogen phosphorus balance, though the methods now to be described were common to all experiments.
Report on a further experiment to compare the fattening values, for beef cattle, of silage made from grass cut at different stages of growth, together with the results of some supplementary experiments
Authors: Dodsworth T. L. , Campbell W. H. McK.
Published: March 2009

1. A feeding trial is described including four groups of cattle fed on grades I, II and III silages and on swedes, straw and oats respectively.

2. The live-weight gains made are recorded, together with the rate of dry-matter intake.

3. The efficiency of the dry matter of the diets was calculated.

4. All three grades of silage produced a significantly greater rate of fattening than swedes plus straw and oats. There was no significant difference between the fattening values of the three grades of silage.

5. The dressing percentages found for 100 silagefed and 71 swede-fed cattle are given. The swedefed cattle yielded a greater average dressing percentage.

6. It is suggested that the higher dressing percentage found for root-fed cattle as compared with silage-fed cattle can be attributed to the more rapid elimination of dietary water from the body in rootfed cattle.

7. An animal behaviour study is described, the time spent by cattle on the four diets, eating, cudding and lying down, being determined.

8. Cattle fed on grass silage spent longer on feeding plus cudding than swede-fed cattle.

9. An experiment is described designed to determine the effect of the dry-matter percentage of the diet on the dry-matter intake of ruminants.

10. The results indicate that when ruminants are subsisting on a diet consisting solely of succulents, the dry-matter intake is depressed when the dry-matter percentage of the diet falls.
Evidence of gene-controlled sterility in bulls
Authors: Donald H. P. , Hancock J. L.
Published: March 2009

A study has been made of the relationships of sterile Friesian bulls manifesting ‘knobbed’ spermatozoa, and the conclusion drawn that the characteristic defect of the acrosome is due to an autosomal sexlimited recessive gene (kn).
Studies on the habits of Zebu cattle II. Individual and group variation within a herd
Authors: Taylor J. I. , Rollinson D. H. L. , Harker K. W.
Published: March 2009

Data collected during 336 hr. of observation with ten Zebu cattle were examined to assess the extent of variation between these animals and the extent to which these animals conform to the general herd behaviour. A further use was made of the data to discuss the effects of individual animal behaviour on the numbers of animals it is necessary to observe.
The effect of environmental temperature and humidity on the rectal temperature of calves
Authors: Beakley W. R. , Findlay J. D.
Published: March 2009

1. The rectal temperatures of three 4-month-old Ayrshire bull calves were measured in individual 6 hr. daily exposures to 15, 20, 25, 30, 35 and 40° C. dry-bulb temperature at low humidity (17 mg./l. absolute humidity) and to 30, 35 and 40° C. at high humidity (7 mg./l. saturation deficit). The experiments on each animal lasted 45 consecutive days and consisted of five replications of these nine environmental conditions. Measurements of rectal temperature were made every 5 min.

2. The rectal temperatures of the animals rose with increasing environmental temperature and humidity.
The effect of environmental temperature and humidity on the skin temperature of Ayrshire calves
Authors: Beakley W. R. , Findlay J. D.
Published: March 2009

1. The skin temperatures at each of eight positions on the trunks of three 4-month-old Ayrshire bull calves were measured at 5 min. intervals in individual 6 hr. daily exposures to dry-bulb temperatures of 15, 20, 25, 30, 35 and 40° C. at 17 mg./l. absolute humidity, and 30, 35 and 40° C. at 7 mg./l. saturation deficit in a modified form of Latin square arrangement of environmental temperature. The schedule of experiments on each calf lasted 45 consecutive days and consisted of five replications of each of the nine environmental conditions.

2. The skin temperatures of the calves all rose with increasing environmental temperature, humidity and time of exposure.
The nutritive value of herring ‘alkali-reduction’ meal for chicks
Authors: Carpenter K. J. , Duckworth J.
Published: March 2009

1. Herring ‘alkali-reduction’ meal—a by-product from the alkali process of herring oil extraction—has been tested as a protein supplement for chicks.

2. At high levels of feeding it was toxic.

3. At low levels of feeding its nutritive value was low compared with other fish meals.

4. The method of manufacture of reduction meal destroys vitamin B12and cystine, but supplementation of the material with vitamin B12and cystine did not greatly enhance its feeding value.
Studies on the soluble nitrogen content of dried samples of grass silage
Authors: John A. , Barnett G. , Miller T. B.
Published: March 2009

1. The relationship between the soluble nitrogen content (soluble nitrogen/total nitrogen) of samples of dried silage and the pH of the corresponding wet samples has been investigated. It has been shown that a relationship exists between the two, and that when Ns/Nd is high the pH is low and vice versa. Moreover, the product Ns/Nd × d.m. is also related to the pH.

2. Again it has been shown that the ratio Ns/Nd bears a relationship to the digestibility of the silage as measured by the Wedemeyer Method in the laboratory. The potential usefulness of the ratio in this connexion is being further investigated.
Field nitrates in Gezira soil
Authors: Jewitt T. N.
Published: March 2009

The results of two sets of soil nitrate measurements on the three-course rotation plots at the Gezira Research Farm are described. The first set is a long-continued series taken over 21 years; it shows for the first foot samples that there is a distinct tendency for nitrates to be depressed during the rainy season, this tendency being more marked in the more open rotations. This is ascribed to washing down of nitrates. The second set of measurements shows accumulations in the second foot and a distribution consistent with downward movement.

In the Sudan Gezira the yields of irrigated cotton are positively correlated with the amount of rainfall in the 6 weeks before sowing. It follows from the work described here that this is not due to increased nitrate in the top foot of soil at sowing time.

The sampling of this experiment for nitrate was started by my predecessor, H. Greene, and continued by O. W. Snow. The field experiment itself has been conducted by the Plant Physiology Section of the Research Division of the Ministry of Agriculture.
The effect of undernutrition before calving on the quantity and composition of milk produced by two-year-old heifers
Authors: Flux D. S.
Published: March 2009

Six pairs of 2-year-old monozygous twin heifers were used to determine the effect of underfeeding for 10 weeks prior to calving. Those which had been well fed before calving produced more milk than their sisters which had been poorly fed.

There was no effect on milk or butterfat composition, probably because none of the animals lost much weight after calving.

The effect of the treatment differed markedly between twin pairs, the maximum difference in milk yield being 2866 lb., the minimum 135 lb., and the mean 1057 lb. for 270 days' lactation.

The ratios of between-twin-pair to within-twin-pair variance for butterfat, total protein and lactose percentages of the milk were as follows:
Some effects of dietary crude fibre on live-weight gains and carcass conformation of pigs
Authors: Coey W. E. , Robinson K. L.
Published: March 2009

1. The results of six trials have been examined in which pigs received rations with contrasting levels of crude fibre. The contents of crude fibre ranged from 3½ to 11½% and were related to a variety of basal diets.

2. The main object of the trials was to study the effect of increased levels of dietary crude fibre on carcass conformation, under conditions where there was no disparity in rate of live -weight gain between the pigs receiving the higher and the lower level of fibre. Thus pigs on the high-fibre diets received extra food in order to equalize the intake of digestible nutrients.

3. The results indicate that a rise in the level of dietary crude fibre was accompanied by a fall in the killing-out percentage, and hence by lower carcass weights. This effect was produced even by comparatively small changes, such as a rise from 3½% crude fibre to about 5% crude fibre. The results also show that carcass weight was positively correlated with back-fat thickness to a marked degree.

4. It is evident that raising the level of crude fibre in the food caused a change in the distribution of live-weight gains, so that when at the same slaughter weights, the high-fibre pigs had lighter carcasses and heavier offal than their low-fibre counterparts. Consequently the high-fibre pigs also had thinner back-fats, and they would tend to grade better under carcass grading systems based on backfat measurements and biased towards thin back-fats.

5. It is suggested that these effects are likely to be produced even in pigs considerably advanced in fattening, and that in younger pigs the drawback of retardation in rate of live-weight gain may also be encountered. Thus the use of high-fibre diets in self-feeding systems, as a corrective against over-fatness, may not normally be the best means of attaining this objective under commercial conditions.
Studies of grazing behaviour in relation to grassland management: III. Rotational compared with continuous grazing
Authors: Hancock John , McMeekan C. P.
Published: March 2009

1. A series of observations on the grazing behaviour of identical twin cattle on two contrasting systems of pasture management—rotationally and continuously grazed—is described.

2. The rotationally grazed cows averaged only 11 min. (day/cow) shorter feeding time and 18 min. shorter ruminating time than their continuously grazed co-twins. The total time they spent in work was thus 29 min. shorter.

3. While the average differences in total work over the whole trial was not great, the continuously grazed cows worked for appreciably longer daily periods at the time of seasonal feed shortage during which time the rotationally grazed cows were buffered by their pasture diet being supplemented with silage.

4. The differences in grazing behaviour between the cows of the two treatments, together with the magnitude of the seasonal variations which occurred in both groups, indicated that dairy cows attempt to maintain a stable production in the face of adverse pasture conditions by increasing their feeding time.

5. Previous conclusions based on observations of uniformly treated twins regarding the importance of heredity in the determination of grazing behaviour were fully confirmed.
Small plots and automatic rain shelters: a field appraisal
Authors: Legg B. J. , Day W. , Brown N. J. , Smith G. J.
Published: March 2009

Two rain shelters, each covering an area of 210 m2, have been built at Rothamsted for use in tillage experiments and drought experiments. Each shelter automatically moves over the experimental area when rain starts, and moves away when rain stops; thus all rain is kept off, but other aspects of the microclimate are little affected. Small experimental plots were used, and, except in the 0·5 m strips at the plot edges, the height and yield of a barley crop were uniform. Irrigation water to some plots was labelled with tritium; when applied to very dry plots, a measurable proportion of this water moved laterally by more than 1·0 m. However, the total quantity of water transferring between adjacent plots was not large enough to inconvenience the tillage or drought experiments.
The feeding and mating behaviour of pollen beetles (Meligethes aeneus Fab.) and seed weevils (Ceutorhynchus assimilis Payk.) on oil-seed rape (Brassica napus L.)
Authors: Williams Ingrid H. , Free J. B.
Published: March 2009

During the early period of infestation of winter rape, pollen beetles and seed weevils were mainly feeding and attaining sexual maturity. Before a crop flowered pollen beetles fed on buds but only some of those which they had perforated to obtain pollen dropped off. When flowering started adults obtained pollen from flowers rather than from buds. They laid their eggs in the buds but not in the flowers. Larvae moved from flower to flower up the raceme and caused no damage. Probably many podless stalks have been wrongly attributed to pollen beetle damage.

Overwintered seed weevils caused no damage by feeding on rape pods. New generation seed weevils caused some loss of seed weight and viability when feeding on pods of spring rape; this is probably unimportant on a field scale.

Pollen beetles and seed weevils mated from mid-May until the emergence of new generation adults; these did not mate before hibernating.
Plant-breeding studies in leguminous forage crops: II. Further observations on natural cross-breeding in winter beans
Authors: Fyfe James L.
Published: March 2009

1. Using the method given in the first paper in this series, estimates of p and a have been obtained for farm crops of winter beans grown in 1950 and 1951, p being the frequency of a dominant allele, in this case for black hilum, (1 — α) the proportion of successful fertilizations in which the pollen comes from the same plant as the ovule and α the proportion in which the source of pollen may be any plant in the crop. In the 1950 crop the estimates were in the 1951 crop they were The difference in the estimates of p is not surprising in view of the fact that the two crops were grown from different stocks of beans. The difference in the estimates of α is possibly due to the 1951 crop being much the denser.

2. In both crops, as in the case previously reported, selection of high-yielding parents produced a frequency distribution of genotypes showing no influence of inbreeding. The data from the 1951 crop failed to give a satisfactory fit with expectation. Both these facts are unexplained by the simple model of a Mendelian population varying at only one locus and with all genotypes of equal fitness. They can both be explained by amending the model so that the population is considered to vary at several loci and that heterozygotes have a slight advantage.

3. Theoretically, a bulk made up of the produce of parent plants selected for high yield should contain substantially more heterozygotes than a bulk of produce of unselected parents. This was confirmed by hilum colour counts. Estimates of yield show that the greater heterozygosity is not reflected in any increase in yield. A possible explanation is offered in terms of information theory.
The production of ketonaemia and pregnancy toxaemia in ewes through manipulation of the feeding level
Authors: Gill J. C. , Thomson W. , Park G. T.
Published: March 2009

1. Trials over 2 years involving 120 Half bred ewes were conducted in outdoor paddocks with controlled feeding. A study was made of the effect of varying the level of feeding during pregnancy on production of ketonaemia and pregnancy toxaemia.

2. Blood ketone levels were low and pregnancy toxaemia absent in ewes gaining weight during the latter part of gestation, but ewes failing to gain weight over the same period were subject to ketonaemia and pregnancy toxaemia. A reduction in the ration of fat ewes for a 3-week period, imposed more than 5 weeks before lambing, had no detrimental effect.

3. A significant correlation was found between loss in weight and highest ketone figure in the highthroughout and the high-checked groups in 1952 and in the high-checked-high group in 1953.

4. High ketonaemia was not always indicative of pregnancy toxaemia, since of the twenty-nine ewes which had, on one or more occasions, over 20 mg. β-hydroxybutyric acid per 100 ml. blood, seven showed signs of pregnancy toxaemia and twentytwo did not.

5. In the cases reported, the time of appearance of the first symptoms of pregnancy toxaemia was around 14 days from the estimated lambing date, and affected ewes tended to lamb before term.

6. On a comparatively low level of nutrition, only one case of pregnancy toxaemia occurred, though some animals had marked ketosis. In well conditioned ewes reduced to a similar level during the critical period, there was a high incidence of pregnancy toxaemia, and in most of these cases a high degree of ketosis.
Hydrolysis of the cell-wall carbohydrates of grasses by carbohydrases in relation to voluntary intake by sheep
Authors: Jones D. I. H. , Bailey R. W.
Published: March 2009

The relationship between the voluntary dry-matter intake of grasses and theirin vitrodigestibility (DOMD), chemical composition and susceptibility to enzymic hydrolysis was examined in two experiments. The grasses were artificially dried and represented a range of species and varieties cut at various growth stages.

In both experiments some 70% of the observed variation in intake could be attributed to differences inin vitrodigestibility between the grasses and between the growth stages when harvested. Estimations of acid detergent fibre, pepsin solubility and cellulose generally accounted for less than 70% of the variation in intake.

The enzyme digestion techniques, on the other hand, accounted for up to 79% of the variation. The content of enzymically unhydrolysable cell wall gave the highest correlation with voluntary intake (r= −0·88 and −0·89, residual standard deviation 5·5 and 6·2, for the two experiments).

It is concluded that simplified techniques based on cellulase digestion of plant material may be advantageously applied to breeding programmes with the expectation of identifying material high in digestibility and with good intake characteristics.
Varietal response by sugar beet to nitrogen, sodium and potassium fertilizers
Authors: Draycott A. P. , Russell G. E.
Published: March 2009

Three preliminary experiments at Cambridge (1904–70) indicated that several varieties and breeding lines of sugar beet differed in their response to fertilizers. Three factorial experiments were therefore made at Broom's Barn (1970–2) to measure response by four widely differing varieties of sugar beet (Sharpe's Klein ‘E’, Maris Vanguard, V.T.137 and Anglo-Maribo Poly) to nitrogen (0, 75 and 150kgN/ha), sodium (0 and 250 kg N/ha) and potassium (0 and 400 kg K/ha) fertilizers. Increases in sugar yield from 75 kg N/ha by each of the varieties were remarkably similar and giving a further 75 kg N/ha neither increased nor decreased the yield of any variety on average over the three experiments. The yield response to sodium and potassium was greatest in Sharpe's Klein ‘E’ and least in V.T.137; however, as with nitrogen, varieties responded inconsistently from year to year and the interactions were not statistically significant for data pooled over the three experiments. These experiments indicate that varietal differences in fertilizer requirement are unlikely to be important in commercial practice.
Effects of starch fermentation products on roughage digestion
Authors: Hynd P. I.
Published: March 2009

The potential benefits of high-energy supplements, such as cereal grains, for grazing ruminants are commonly eroded by an accompanying depression in the digestion and intake of the basal herbage (McCullough, 1959). Low ruminal pH (< 6·0) induced by the rapid rate of production of the acids of starch fermentation, and competition between cellulolytie and amylolytic bacteria for limited nutrients, are known to be responsible for inhibition of cellulolysis (Terry, Tilley & Outen, 1969; Stewart, 1977; el Shazly, Dehority & Johnson, 1961). However, there are reports of reduced roughage digestion when nutrients appear to be non-limiting and pH is maintained above 6·0 (Gilchristet al.1979; Henninget al.1980). The possibility remains that intermediates or end products of starch digestion have specific inhibitory effects on the numbers of cellulolytie organisms or on the activity of their extracellular cellulases.