1. Eight experienced judges used a 20-point scoring scale in different ways when assessing the ‘proportion of lean to fat’ from the same photographs of cut bacon sides presented in the same arrangements. The average score for the 220 judgements made during the experiment by a single judge, which represents his over-all level of scoring or ‘standard of judging’, ranged from 13·7 to 12·0. The standard deviation, a measure of the degree of discrimination attempted by the judge, ranged from 3·26 to 4·74.

2. The judges varied in their consistency of assessment or ‘repeatability’. The standard error for a single judge, measuring the extent of the variation of his scores within photographs, ranged from 0·89 to 1·99. The judges who attempted to discriminate most between photographs tended to be the least consistent in their judgements, although one judge was a notable exception to this trend.

3. The consistency of judgement tended to decrease from the good (high-scoring) rashers to the poor (low-scoring) rashers, but this effect was more marked for some judges than for others.

4. Some of the variation in the scores awarded to each photograph was due to alterations in the standard of judging from batch to batch. When this was allowed for, the standard errors were all reduced and ranged from 0·61 to 1·31. The judges tended to adjust their standards according to the average quality of the batch being assessed. This led to the variation among the average scores for the batches being less than it would have been had their standards remained constant.

5. Alterations in the standard of judging during the experiment affected the scores awarded to good (high-scoring) rashers rather less than those awarded to poor (low-scoring) ones.

6. The correlations between the individual judge's mean scores for the forty-four photographs and the over-all mean scores were very high. For seven judges, they ranged from 0·962 to 0·984, whereas for the eighth judge the correlation was 0·918. The lower correlation for this judge was due to two rashers with very thin fat being heavily marked down.

7. The correlations between the over-all mean scores and two different combinations of three objective measurements were both about 0·92; these measurements were therefore slightly less closely related to the over-all scores than were an individual judge's mean scores.

8. The possibility of making the experimental technique more realistic and of improving the precision of such visual judgements by providing photographic scales of reference are discussed.

Quantitative and qualitative bacteriological comparisons were made between complementary samples of cud and rumen contents using five fistulated cows receiving various diets; no marked differences were observed between samples taken from the same animal at the same time. This, with the method of collecting cud described, simplifies bacteriological evaluation of the rumen contents of intactanimals.

1. The volume of rumen liquor in milk-fed calves at different ages up to 32 weeks was estimated by injecting polyethylene glycol into the rumen and subsequently determining its concentration in the rumen liquor. This volume increased progressively with age in relation to unit body weight. The increase xswas approximately fourfold between 4–8 weeks on the one hand and 28–32 weeks on the other.

2. The amount of milk entering the rumen during a feed was estimated at different ages up to 32 weeks by the subsequent determination of the volume and fat content of the rumen liquor. In the majority of cases less than 5% of the milk fed entered the rumen. There did not appear to be any increase in the quantities of milk entering the rumen as the calves got older.

3. An estimate of the rate of flow of fluid into and out of the rumen (other than milk at feeding) was made by measuring the rate of disappearance of polyethylene glycol from the rumen. A mean figure of 255 ml./hr./100 kg. body weight s.d. ± 50 was obtained in this way. It is suggested that this value probably represents the rate of flow of saliva.

4. Magnesium, in a concentration up to about 8 mg./100 ml. in the rumen liquor, did not appear to be absorbed to more than a small extent through the rumen wall.

1. Attempts to investigate the physical properties of bran, and other feedingstuffs, with regard to their ability to absorb and retain water, have been outlined.

2. Two experiments have been described in which pigs were fed bran, fibrous cellulose, or different levels of powdered cellulose, added to normal pig rations. These experiments involved 24 hr. faecal collections, and ultimate slaughter of the animals, together with analysis of faecal material and gut contents.

3. The addition of bran or fibrous cellulose to a ration causes a reduction in the average percentage of dry matter in the faeces, but tends to emphasize fluctuations in faecal dry-matter percentage, which are attributed to fluctuations in rate of passage through the large intestine.

4. The behaviour of the powdered cellulose was anomalous, giving rise to hard stools. It appeared to be almost inert in relation to water.

1. The desirability of employing the genetic variation present in diploid and tetraploid wild species for the improvement of the cultivated hexaploid species stimulated an investigation into the synthesis of various amphiploid forms in Avena.

2. Five amphiploids at the hexaploid level have been produced, but the present investigation is limited to the amphiploids developed from the cross A. barbata (2n = 28)×.A. strigosa subsp. hirtula (2n= 14), their hybrids with the natural hexaploid species and with other amphiploid types.

3. These amphiploids, like their parents, possessed black paleae, with hairs and a fairly strong geniculate awn on both the lower and upper grains. The bases of both the lower and upper grains possessed the articulation surfaces characteristic of A. fatua. Their hybrids with A. fatua were similar in spikelet morphology, but the A. sterilis type of spikelet was dominant in both the amphiploid 6x × A. sterilis and amphiploid 6x × A. byzantina. Partial dominance of the cultivated type base over the shedding type was evident in crosses with A. sativa and A. nuda but the naked caryopsis and multiflorous spikelet were recessive in the latter cross. In crosses between the A. barbata/A. hirtula 6x amphiploid and the A. abyssinica/A. strigosa 6x amphiploid (Cc 4387) the hybrid exhibited a reversal of dominance relationships, with the cultivated base type of Cc4387 being completely recessive to the shedding base.

1. Two experiments have been described in which pigs were fed different levels of fibrous cellulose superimposed on a highly digestible purified basal ration. These experiments involved 24 hr. faecal collections and ultimate slaughter of the animals, together with analysis of faecal material and gut contents.

2. The results of these experiments, together with those from experiments described in the previous paper in this series, have provided the basis for a discussion of the effects of adding bran and cellulose to pig rations, and of the influence of the progress of the residues of feeds through the digestive tract, on the pattern of excretion and the dry matter content of the faeces.

1. The peripheral metabolism of thyroxine in sheep in pregnancy was investigated by measuring the rate of disappearance from blood of injected 131I-thyroxine. Only limited changes in thyroid metabolism during pregnancy were observed. The rate of turnover of thyroxine slightly increased, but this was not accompanied by increased levels of plasma protein-bound iodine (PBI), or thyroxinebinding protein.

2. In a 3·5-month foetus, the thyroid was active, and a marked concentration of iodide by the foetus was observed. The significance of this activity could not be assessed in the absence of knowledge on the placental passage of iodide or thyroxine in the sheep.

3. Knowledge of thyroid metabolism is inadequate at present to explain any correlation between animal productivity and either hormone supplementation, or PBI concentration.

1. Seven experiments on spring barley and five on spring wheat carried out in 1955–7 compared dressings of ammonium sulphate and calcium nitrate applied to the seedbeds at 0·3 and 0·6 cwt. N/acre. The fertilizers were tested both when broadcast and when drilled with the seed.

2. Consistently higher yields of barley were produced by drilling than by broadcasting ammonium sulphate. Drilling calcium nitrate at 0·3 cwt. N/acre was superior to broadcasting for barley but when applied with the seed at 0·6 cwt. N/acre this fertilizer retarded germination and early growth and gave smaller yields than were obtained by broadcasting. Broadcast dressings of both fertilizers gave higher yields of wheat than combine-drilled dressings. There is a considerable risk of fertilizer ‘scorch’ when compound fertilizers containing all their nitrogen in nitrate form are combine-drilled at rates sufficient for maximum yield. This risk may be discounted when adequate rain follows drilling but the check to germination may be sufficient to reduce yields in dry springs, on light soils, and on badly prepared seedbeds. Fertilizers containing all their nitrogen in ammonium form appear to be quite safe at the rates of dressing tested in this work.

3. Calcium nitrate and ammonium sulphate gave similar yields and nitrogen contents of both crops when the fertilizers were broadcast on the seedbed. Nitrates applied at sowing-time to cereals grown in the drier parts of the country do not appear to be leached out of the root-zone before they can be taken up by crops.

1. Thirty-four lambs varying from 1 week old up to 22 weeks have been treated with: (a) p.m.s. alone; (b) Progesterone + p.m.s.; (c) p.m.s. + chorionic gonadotrophin (c.g.).

2. At 1 week old the lamb's ovaries were unresponsive to treatment (a).

3. At 4 weeks follicular growth was obtained in groups treated with both (a) and (b).

4. At 8 weeks of age follicular stimulation was obtained from treatment (a), follicle luteinization from (b), and ovulation from (c).

5. At 10 weeks luteinization was observed in (b) and ovulation in (c).

6. At 12 weeks luteinization occurred following treatment (a) and ovulation followed treatments (b) and (c).

1. An experiment has been described in which pigs were fed rations containing four different levels of cellulose, each ration being fed successively at three different levels of water intake. The cellulose levels were superimposed on a highly digestible basal ration.

2. It appears that altering the level of water intake, while keeping the ration constant, has only a very limited effect on the level of faecal dry-matter percentage, and on the pattern of variation therein.

3. Further evidence is cited in support of the theories, advanced in a previous paper, relating to the influence of fibrous cellulose on water relationships in the digesta and faeces.

Since the introduction of silos and associated techniques of ensilage production in the late 1870's, maize has been the principal silage crop in the United States. Many British authorities agree that maize is a ‘splendid silage crop, highly nutritious, heavy yielding and easy to cut and handle’ (Bond, 1948, see also Watson & Smith, 1956; Woodman & Amos, 1944) but, nevertheless, it is very rarely grown in Britain for silage. In this country, as in most countries of Western Europe, the predominant aim of maize cultivation has been to produce succulent green fodder for direct feeding to animals during time of drought and consequent grass shortage. The acreage grown in England is small, but in Western Germany in 1955 there were about 100,000 acres of fodder maize (Becker, 1956), while in France, in 1954, the acreage exceeded 500,000 (Desroches, 1955). Recently in Western Europe considerable interest has been shown in the possibilities of maize as a silage crop, and within the past few years preliminary results have been reported from Holland (Becker, 1956; Anon. 1954, 1955); Denmark (Bagge & Hansen, 1956); Belgium (Lacroix, 1955; Ledent, 1955); Germany (Jungehulsing, 1955; Schell, 1954); France (Desroches, 1955), and Switzerland (Bachmann, 1952).

1. Fractionation experiments have been described in which powdered bone materials were extracted with dilute acids using three different techniques. Ethylene diamine tetracetic acid (EDTA) was also used in one series of experiments.

2. The results suggested that the magnesium of bone is present in two main forms, one relatively soluble and the other relatively insoluble in dilute acids.

3. It appeared that a large proportion (at least 70%) of the total bone magnesium was located on the surfaces of the bone crystals either as Mg2+ or MgOH+ ions adsorbed at the primary cation adsorbing centres (the surface phosphate ions of the apatite crystals) or as Mg2+ ions replacing surface Ca2+ ions of the crystal lattice.

4. Evidence that magnesium carbonate does not occur in significant amounts in bone salt was obtained.

5. These results were discussed in relation to the hypomagnesaemia of lactating cows.

6. The carbon dioxide of bone also appeared to be present in two main forms, one relatively soluble and the other relatively insoluble in dilute acids.

1. A total of forty pigs (four litters) were slaughtered at weekly intervals from birth to 5 weeks of age.

2. Results are given for the changes in weight of different parts of the digestive organs and their contents with increasing age, and for the content of NaCl and of total acidity in the stomach contents.

3. Stomach pH was on average more alkaline than pH 3.4 at all ages up to 5 weeks; the average pH of the duodenum was 6.5 and of the small intestine 6.4.

4. Total NaCl and total acidity in stomach contents remained roughly constant from birth up to 5 weeks of age. No free HCl was detected in any of the stomach contents of the pigs.

5. The consistency of the stomach contents varied with the age of the pig; the hard milk clot which was characteristic of the contents at 2–3 weeks of age appeared softer and more broken in older pigs.

Quantitative aspects of skin follicle population growth and maturation in post-natal life from birth to 16 months have been studied in four groups of N-type and non-N New Zealand Romneys. The following characters were observed on skin biopsy specimens from a standard position on the mid-side in all cases: total and primary follicle population density; ratio of secondary to primary follicles ; primary and secondary fibre diameter; primary/secondary fibre diameter ratio ; and the incidence and degree of primary and secondary fibre medullation.

No important differences were found between the genotypes examined in any of these characters except primary fibre diameter , the primary/ secondary fibre diameter ratio ; and the incidence and degree of primary and secondary fibre medullation. These characters individually, but especially in combination, appear of great diagnostic value at all post-natal ages in discriminating N-type from non-N genotypes, in terms which reduce the number of assumptions necessary on the relations between the fibre types of the staple and the follicles of origin in the skin.

The effect of environment on the production and size of eggs, feed efficiency and mortality of New Hampshire hens in individual cages was studied simultaneously in five areas of Guatemala having temperatures covering a range of 0°–45° C. with variable humidities.

While birds housed in the tropical lowlands did show visible signs of thermo-stress, there were no significant differences in egg size, production, feed consumption, mortality and body weight between areas or between groups within areas. The inconsistency of these data with other published reports is explained on the basis of the observed extremely wide diurnal range for temperatures and humidities. An attempt is made to present accepted physiological phenomena in the form of a working hypothesis wherein the diurnal temperature range is related to the fowl's tolerance to thermo-stress.

1. Forty Large White pigs varying in age from birth to 5 weeks were slaughtered and their carbohydrate digesting enzymes studied for any change in activity with increase in age.

2. Pancreatic amylase, sucrase and maltase increased from low levels at birth to high levels at 5 weeks of age.

3. The total amount of lactase present at birth and of small intestine amylase at 1-week-old was maintained at a constant level up to 5 weeks of age. The increased weight of the intestine with the growth of the pig made the quantity of these enzymes appear to decrease with age when the values were expressed per kg. body weight or per g. dry tissue.

4. Anaemia had no marked effect on the activity of the enzymes though the rate of enzyme development appeared to be retarded in the case of maltase.

5. The quantity of pancreatic amylase present in the pancreas was sufficient at all ages to digest the amounts of starch likely to be included in a synthetic diet. Maltase, on the other hand, appeared to be limiting in early life.

1. The efficiency of food conversion by pullets and yearlings fed on high- and low-energy diets has been determined.

2. Egg production was slightly higher by birds fed the low-energy diet for both pullets and yearling hens; pullets laid more eggs than yearling hens.

3. For each age, the gross food intake was greater for birds fed the low-energy diet; the consumptions of digestible protein, non-protein digestible energy and metabolizable energy were the same for both diets and both ages of bird.

4. The food cost per dozen eggs was slightly greater in the yearling year when the cost of rearing the pullets was ignored, and about the same when it was included.

5. The efficiency of utilization of digestible energy and protein showed only a slight decrease from the pullet to the yearling year.

6. The variation in the composition and digestibility of eighteen consecutive mixes of the highenergy diet and twenty-five of the low-energy diet was: crude protein 2%, non-protein digestible energy 5% and metabolizable energy 0·4 kg. cal./g. The digestibility of the crude protein and oil was 87%, for both diets; carbohydrates were 81% digestible in the high-energy diet and 59% in the low-energy diet.

1. Results are reported of an experiment carried out under commercial conditions to obtain information on the effect of four different levels of allmeal feeding on the performance and carcass grading results of fattening pigs.

2. There were four treatments. All pigs were given the same meal mixtures and were fed dry and ad lib. up to four different daily maximums, namely, 6½, 6, 5½ and 5 lb. meal/pig/day. There were five pens of nine group-fed pigs on each treatment, involving a total of 180 pigs. The pigs were on experiment from approximately 8 weeks of age to bacon weight. Comprehensive carcass measurements were made on all pigs.

3. The results showed that as the level of feeding was decreased, the growth rate of the pigs, back fat thickness and belly thickness were reduced, and the depth and breadth of eye muscle were increased, while the efficiency of food utilization, carcass dressing percentage and carcass length were not markedly affected. Commercial grading results similarly improved as the level of feeding was reduced.

4. It was concluded that under the conditions prevailing, the maximum daily meal allowance should be of the order of 5½ lb./pig in order to obtain relatively satisfactory carcass grading.

5. Subdivision of the carcass measurement and commercial grading data according to sex of pig showed that in general at each level of feeding the carcasses of the female pigs were superior to those of the male animals.

The possibilities of segregating pigs according to sex during fattening as a means whereby undue retardation in the growth rate of the females might be prevented without adversely affecting their carcass grading, was discussed.

Data concerning a random sample of flocks in Yorkshire and Lancashire were collected, in the form of answers to a questionnaire. Information was received from 88% of the 272 farms approached.

The present survey, a more detailed repetition of one performed in 1952–53, has extended the information already collected and enabled deductions to be made regarding the relationship between disease losses, breed and husbandry methods. The advantages and disadvantages of this type of survey are discussed.

1. The normal pattern of grazing behaviour of free-range indigenous cattle under conditions of lenient stocking and overstocking has been studied throughout the year.

2. There was a fairly fixed daily pattern of herd behaviour. The cattle usually started day grazing round sunrise and ceased approximately 1 hr. after sunset. There was a morning and afternoon peak of intense grazing activity separated by a rest period and watering about midday. There was usually one peak of night grazing.

3. The average daily grazing times varied from 8 hr. during the rains period of relative feed abundance, to about 13 hr. during the dry season period of malnutrition.

4. During the dry season there were no major differences in grazing times between the leniently stooked and overstocked groups. Both herds were losing weight.

5. The relatively greater weight gains of the overstocked herd compared with the leniently stooked group during the rains resulted from the increased grazing times of the overstocked herd.

6. The night grazing remained fairly constant at approximately 20% of the total daily grazing time.

7. There were no seasonal effects on the pattern of grazing behaviour. High daytime temperatures did not cause an increase in the proportion of night grazing of indigenous cattle.