1. Semen was collected from bulls by means of the electro-ejaculation method developed by Thibault et al. (1948).

2. A copious sperm-free fraction of the ejaculate, produced in the early phase of stimulation, was examined for its chemical composition.

3. This secretion was found to have a low protein content, but its chloride concentration was higher than in the sperm-containing fractions of the ejaculate. Fructose and citric acid occurred in very low concentrations, and 5-nucleotidase was absent in the pre-sperm secretion. This indicates clearly that the secretion does not originate either in the seminal vesicles or in the ampullar glands; it is probable that it represents a discharge from the urethral glands.

4. The effect of the pre-sperm ejaculate fraction upon bull sperm fructolysis and motility was examined; both were unaffected by a considerable excess of this secretion.

5. The chemical composition of the pre-sperm secretion makes it unlikely that under physiological conditions it could play a role in the nutrition of the spermatozoa; presumably, its chief function is the clearing of the urethral passage prior to the descent of the semen proper.

1. The extraction of leaf protein from autumn-grown perennial ryegrass is described.

2. The composition, chemical analysis and rate of feeding of two mashes compared in the experiment are given. The same basal cereal mixture was used in each ration, with fish meal added to one and leaf protein and minerals to the other.

3. Two groups of three birds were kept on each ration. Nine-month-old Brown Leghorn × Light Sussex pullets, in full lay, were used.

4. The birds were given a 6 weeks' preliminary period on a uniform ration to accustom them to the experimental conditions and to ascertain their potential egg production.

5. In a 10-week feeding trial no difference occurred in the number of eggs or the total weight of eggs laid by the birds fed on either ration.

6. A small loss of body weight occurred in the birds in both treatments.

7. Egg-quality determinations indicated that the specific gravity of the eggs was not affected by the differential feeding. Yolk height was greater in eggs from birds fed on the ration containing fish meal. This ration also resulted in a higher number of eggs with rough shells and containing a higher content of foreign bodies.

8. The eggs from both treatments had low ‘Yolk-colour indices’, showing that the leaf xanthophylls were not present in quantities in the leaf-protein extract.

1. Two live-weight gain experiments using dayold chicks are described. A mash containing a basic ration with leaf protein was compared with a control mash containing the basic ration plus fish meal.

2. Details of the source of the leaf protein, its extraction and chemical analysis are given.

3. The composition and analyses of the mashes are recorded, together with their rate of feeding.

4. The live-weight gains at fortnightly intervals are discussed and the results adjusted for sex of chicks, weight at day-old and level of protein in the mash.

5. In the first experiment some of the pullets from each treatment were fed on a commercial growers' ration from 6 weeks old to maturity.

6. The birds on both treatments in the two experiments were equally healthy. The mortality rates were normal. The leaf-protein chicks had deep yellow pigmentation.

7. The results of the experiments are compared. In the first the leaf-protein mash was as valuable as the fish-meal mash; in the second experiment the fish-meal mash proved to be superior.

8. A new method of measuring the biological value of the protein of herbage plants is suggested, using extracted protein fed to chicks or rats.

9. It is concluded that a mash composed of homegrown cereals plus leaf protein with vitamin supplements, a balance of minerals and additional aminoacid if necessary, would be suitable for rearing chicks.

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.

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.

The materials and methods have been described in the first paper of this series (Glover, 1953). All experiments were of 33 factorial design (Yates, 1937) involving three different levels of supply of nitrogen, phosphorus and potassium.

The results of the measurements are shown graphically in Figs. 1–4 inclusive. Because of the limits set by reproduction of Figs. 1 and 2 it is impossible to show minor variations due to different treatments. Where the curves of uptake run together one broad line is used to denote this. Deviations from this line are shown where they occur. Superimposed on the figures are lines denoting the length of the tasselling and silking periods. Thus a line covering a period of, say, 10 days and bearing the symbol T shows that tasselling in the particular series was completed in that period, and the first tassel was set at the date corresponding to the start of the line.

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.

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).

1. The rectal temperature of piglets was determined (a) at intervals from birth up to 18 days, (b) at the same time daily until the piglets appeared to be fully thermoregulated.

2. The rectal temperature of a vigorous piglet during parturition may be as high as 104–105° F.

3. During the first few minutes after birth the temperature falls to about 100° F., partly as a result of the lower temperature of the external environment and partly as a result of rapid evaporation of amniotic fluid with which the young pig is covered. The fall in temperature is greater with lighter pigs than with heavier pigs.

4. The temperature falls until the young pig finds its way round to the teats and starts to suckle. This struggle and activity of suckling together with the warmth in the sow's nest causes a temporary rise in temperature. During the first rest the temperature falls again to about 100° F., but vigorous pigs have a normal temperature within 12 hr.

5. Piglets deprived of milk after 5 hr. and 16 hr. suckling experienced a more or less steady fall in temperature to about 98° F. in 2–3 days, when the pigs were comatose and were killed. In the case of a pig which had suckled for 7–8 days the temperature remained more or less normal for 2 days and then declined to 95° F. during 5–6 days. The length of survival depends largely on the initial weight, i.e. on the reserves accummulated during the suckling period, and possibly on the thickness of the insulating layer of subcutaneous fat.

1. Piglets reared in a cold building but in pens provided with electrically warmed or wooden beds weighed considerably more at 8 weeks old than piglets reared in pens with solid concrete floors covered with thin permeable cork-tar bricks. At 3 days and 3 weeks old there were no differences in live weight between the three groups.

2. Before weaning at 8 weeks old the piglets reared on concrete floors had very much poorer appetites for solid food than had those from the other two groups.

3. Although the blood haemoglobin concentrations of piglets on warmed and wooden floors rose between 3 and 8 weeks of age, the haemoglobin concentrations in the group on concrete floors fell. The differences in concentrations between groups at weaning just failed to be statistically significant at P = 0·05.

4. Under the conditions of this experiment the provision of electrically warmed or wooden floors diminished but did not eliminate the incidence of a pathological liver condition in pigs which has been attributed to poor housing conditions.

5. The low weaning weights, poor appetites, low haemoglobin concentrations at weaning and the presence of the liver disease in piglets born on concrete floors were probably interdependent, but the mechanism and direction of this interdependence could not be explained from the data collected.

Six Romney Marsh ewes exposed daily in a hot-room to temperatures averaging 105° F. dry bulb and 87° F. wet bulb for 2 months prior to the start of the breeding season all experienced oestrus and, as a group, at the same time of year as non-heated controls.

However, when maintained under daily hot-room treatment throughout the pregnancy period only one ewe lambed, suggesting an adverse effect of high temperature on gestation.

In a further experiment to confirm this, eight control ewes all lambed, average birth weight of lambs being 9 lb. 5 oz. Of six experimental ewes exposed to temperatures of 107° F. (dry bulb) and 92° F. (wet bulb) for 7 hr. daily during the last third of pregnancy, one failed to lamb and the lambs averaged 7 lb. 15 oz. A further six experimental ewes exposed to similar room conditions for the last two-thirds of pregnancy produced still smaller lambs, averaging 6 lb. 11 oz. at birth, and three ewes failed to lamb.

The yield of lamb per ewe was 9 lb. 5 oz. for controls, 7 lb. 13 oz. and 4 lb. 1 oz. for ewes exposed to heat during the final third and two-thirds of pregnancy respectively and, in the previous year's experiment, 1 lb. 2 oz. for those exposed throughout the pre-mating, mating and post-mating period.

It is concluded that although high temperature is apparently without effect on the incidence of oestrus in sheep, it is inimical to satisfactory gestation.

1. A semi-lethal gene combination has been found in hexaploid species hybrids involving some strains of Triticum macha, but not in comparable hybrids involving other strains of T. macha. The production of these semi-lethal hybrids can be explained by the interaction of two genes designated as ma and mb.

2. The gene ma is carried in some strains of T. macha. The gene mb is carried in the third chromosome set of all other hexaploid species of Triticum, in Aegilops squarrosa and in Aeg. cylindrica.

3. The semi-lethal gene combination has been found between species which would otherwise produce fertile hybrids and between species which would otherwise produce sterile hybrids. The semilethal gene combination occurs between species which do not overlap geographically.

4. The distribution of the genes ma and mb shows that the gene ma originated in T. macha and that the gene mb originated in Aeg. squarrosa and was introduced from there, during the course of evolution, into the hexaploid species of Triticum (probably excluding T. macha) and into Aeg. cylindrica.

5. Meiosis in semi-lethal plants was comparable to meiosis in normal plants. But the semi-lethal plants showed a reduction in fertility, probably as a result of their poor vegetative growth.

6. The chromosomes of T. macha and T. vavilovi have been no more structurally differentiated than the chromosomes of the other hexaploid species of Triticum.

7. The present study has confirmed that the third chromosome set of the genus Triticum has been phylogenetically derived from Aeg. squarrosa.

1. Pregnancy and lactation had no effect on the digestibility of the dry matter and nitrogen-containing constituents of the ration of Cheviot ewes fed at a constant level.

2. The water consumption of the pregnant ewe was almost doubled during gestation.

3. The digestibility coefficients of dry matter and nitrogen in both pregnant and barren ewes fell considerably from November until the beginning of the following April.

4. The average nitrogen content of a normal fullterm Cheviot foetus was approximately 99 g.

1. A report is given of an experiment to investigate the extent of genotype-environment interaction in the growth rate and reproductive phenomena of certain strains of mice when kept in two food and two temperature environments. Evidence of interaction was found in both characters.

2. The results are considered to be of sufficient interest to justify further work along these lines.

This might either take the form of extensive studies involving many strains and environments chosen more or less at random, or in more limited investigations where the genotypes and environments are especially chosen because of marked differences.

1. Earlier work on the digestibility of Calluna vulgaris has been briefly reviewed.

2. Determination of the digestibility of heather has been made by two methods, viz. (a) the conventional procedure involving the use of metabolism crates and (b) the lignin-ratio technique applied to tethered sheep.

3. A diet consisting of heather alone, and fed in metabolism crates, proved unsatisfactory as a result of low feed intake. Agreement between duplicate sheep in respect of digestive capacity was also poor.

4. Satisfactory feed intakes were attained when heather was admixed at levels of 40 and 70% with hay. At both levels the digestibility of the organic matter was approximately the same, and agreement between sheep was good except for crude protein.

5. The lignin-ratio technique applied to tethered sheep gave digestibility coefficients for organic matter which were consistent with those obtained by the conventional method; the values for crude protein were somewhat higher. While the organic matter of 10-year-old heather was digested to about the same extent as that of 4-year-old heather, its crude protein digestibility was rather less.

6. The advantages and disadvantages of both methods have been discussed; it has been concluded that the lignin-ratio technique is likely to play a useful part in future work of this kind.

7. These preliminary results suggest that heather has a higher nutritive value than earlier work would indicate, and that even the winter foliage may compare favourably with hay of moderate to poor quality.

The inverse relationship described in an earlier publication between phosphate response and the degree of base saturation has been confirmed with three further groups of field experiments. As an alternative to the degree of base saturation soil pH may be employed.

The discrepancies sometimes found with the more acid base-unsaturated soils, between actual phosphate responses and those expected from the degree of base saturation were found to be related to the control yields. In general, the higher the control yield on a distinctly acid soil the more the percentage response to phosphate fell short of that expected, and vice versa. By forming multiple regressions of percentage phosphate response on both control yield and the percentage saturation of the B.E.C. a more accurate assessment of phosphate response is possible than by using the simple regression of response on the percentage saturation of the B.E.C. A measurable soil characteristic that could be used in the multiple regressions instead of the control yield was not found.

Very significant and inverse relationships were established between percentage phosphate response and the amount of water-soluble or citric acidsoluble silica. These silica contents were also found to be significantly and directly related to the percentage saturation of the B.E.C. It appears that measurements of pH, silica and base saturation function similarly in classifying the soils, distinguishing between the almost neutral soils retaining phosphate in an available form associated with exchangeable bases, acid soils with relatively unavailable phosphate associated with iron and aluminium compounds, and soils intermediate between these.

1. The effect on cow health of galactopoietic stimulation with thyroactive materials was determined from a statistical study of the results of a large field experiment involving 2000 cows over a 3-year period.

2. The same experimental procedure was followed on thirty-seven farms scattered over England, Scotland and Wales. This procedure was planned to ensure that half the cows in each herd would receive a course of treatment with iodinated casein or thyroxine, and that the other half would constitute a suitable set of controls. Cows that remained in the herds received second and third treatments in successive lactations.

3. The galactopoietic stimulation was started at a fixed interval after calving, irrespective of the season of the year.

4. The use of the thyroactive materials in successive lactations did not have any serious adverse effects on the health of cows. The effect on productivity was less than had been expected, since the increase in milk yield resulting during the period of hormonal treatment was often largely or completely negatived by a shortening of the lactation period.

5. The incidence of disease was somewhat greater in the treated than the control group, the principal contribution to this difference being from the diseases described as digestive disorders. There were some other differences of lesser significance.

6. The rate of disposal of treated and control groups was almost identical.

7. There were no adverse effects on the reproductive life of treated cows; factors studied were the efficiency of coitus, interval between parturitions, length of gestation and incidence of abnormalities at parturition.