Some published figures relating to the incidence of swarming have been examined, and records obtained in the routine examinations of colonies in honeyproducing apiaries have been analysed. It is concluded that in these apiaries between 10 and 40% of colonies would swarm in an average year, if they were given excess hive space and otherwise left alone. The proportion of colonies which produced queen cells varied from year to year and from one apiary site to another. This variation was presumably due to environmental factors, but it was substantially independent of those factors which determined honey yield. There was no evidence that it was due to the effects of conditions in the years when the queens were reared. After the end of June, at least, the tendency for colonies to produce queen cells was markedly less with queens of the current year than with queens of the previous year, and was probably also less with queens of the previous year than with still older queens. Queen cells were most frequently observed in colonies in the latter half of May and in June and July. The mean time of queen-cell production varied from year to year. Many colonies which began to rear queens eventually ceased to do so with no other treatment than removal of queen cells. Queen rearing did not begin and end in all colonies at the same time; many colonies began rearing queens after others had stopped.

In samples of wild-oat panicles collected in England and Wales in 1951 only two species, Avena fatua L. and Avena ludoviciana Dur., occurred; both were very variable in grain characters but most plants bred true. Plants of all except one type of A. fatua were upright in habit with few tillers and averaged 95% dormant grains at harvest; plants of A. ludoviciana were procumbent or prostrate at the maximum tillering stage with numerous tillers and the percentage dormant grains was lower than in A. fatua.

The taxonomy of wild oats is discussed. Chromosome counts on eleven selections showed that 2n = 42.

Types intermediate between wild and cultivated oats were compared with wild oats.

1. Ayr Line Potato oats was studied in the later stages of development for 3 years under upland conditions in Kincardineshire, Scotland. Some major changes in yield and chemical composition of the crop and certain effects of haymaking have been demonstrated.

2. In each year, between the ‘milky’ stage and full ripeness of the grain, the growth curve falls into the distinct phases of growth, maturity and senescence when dry-matter loss occurs. The position of the peak yield in terms of stage of maturity varies from year to year.

3. Percentage crude protein is low throughout, falling to a minimum after the early ‘milky’ stage and rising again to a maximum at the last cut. Yield of crude protein is highest at the last cut in one year and at the penultimate cut in two years.

4. Percentage crude fibre tends to decrease with increasing maturity, while crude fibre yield is low at both extremes of the experimental period.

5. More detailed chemical analyses at different stages of maturity show total ash content to be low. The content of calcium is especially poor.

6. Separation of the whole of the aerial part of the plant into leaf, stem and inflorescence shows that chemical constituents are being actively re-distributed throughout the plant during the experimental period; with the exception of crude fibre and calcium all constituents estimated tend to be concentrated in the grain with advancing maturity.

7. In one year, dry-matter losses during curing range from 22 to 7% at the first and last cuts respectively, while corresponding figures for crude protein are 18 and 10%.

8. In the absence of digestibility data and feeding trials under Scottish conditions, the tentative conclusion is drawn that in the higher rainfall areas of the north and west where the crop is most likely to be used, cutting between the late ‘milky’ and late cheesy' stages should give optimum results.

9. Attention is drawn to the need for caution in the general application of the results.

Hairiness in wool of Suffolk sheep as a fault was found to be associated with other defects like coarseness of wool fibres, hairiness of the britch, and the occurrence of pigmented fibres. The presence of these various defects was studied in the lamb's tail at docking time, and subsequently evaluated and correlated with the fleece.

The tails were graded according to the nature of the fibres and the spread of halo hairs from the tip to the base into four principal grades which by further subgrading could be made into seven grades. The results were as follows:

(1) There was wide variability in grades of tails within each flock.

(2) Average grade of tails followed in general the mean quality of the adult fleece.

(3) When Border Leicester were crossed with Welsh Mountain the tails of the two reciprocal crosses were found to be of hairy type of tail and nearly like the Welsh Mountain type.

(4) The percentage of coloured tails in the least hairy grades was found to be inversely related to the quality of the tail grade and indirectly to the fleece quality.

(5) The diameter of the wool fibres on the base of the tail is highly correlated with the diameter of fibres from the britch regions or mean fibre diameter from four regions of the body (mid-shoulder, midside, hip and britch).

(6) The mean diameter of the wool fibres obtained from four different parts of the tail was correlated with those of the britch regions only.

(7) The diameter and variability of fibres increased from shoulder to britch in the body and from base to tip in the tails.

(8) The britch and tails of two groups of sheep, one group characterized by coarse and the other by fine britch and tail wool, were studied histologically. There were significant or highly significant differences in the following characteristics in the britch of the two groups: (a) total number of follicles, (b) primary follicles with no medulla, (c) total number of secondary follicles, (d) secondaries with no medulla, (e) secondaries with large medulla. The only type of follicle where a significant difference was found in the tail was in the number of secondary follicles with no medulla.

1. With steers of indigenous cattle, the supplementation of veld grazing with two levels of salt with and without protein in the dry season has been investigated.

2. The feeding of 1 oz. of salt speeded up growth to a strongly significant degree, but under the experimental conditions no benefit was obtained during the dry season from adding a protein supplement to the salt. Protein supplementation without salt produced no significant effects upon growth.

3. The addition of 2 oz. of supplementary salt was found to give some increase in growth when compared with the control, but appeared to exert an inhibitory action as compared with the lower salt level, and again there was no benefit gained from the addition of a protein supplement in the dry season. No reason can yet be given for this.

4. Additional evidence has been given to support the suggestion that the tropical indigenous animal possesses the capacity to stop growing during adverse nutritional conditions.

The amount of phosphorus in composite surface samples and profile samples from a range of agriculturally important soils in the forest and savannah regions of the Gold Coast has been determined. The total phosphorus in each sample has been divided into an acid-soluble, an inorganic alkali-soluble, an organic and a residual fraction. On the surface samples these fractions, together with the soil pH, organic carbon and Bray ‘quick-test’ available phosphorus, have been related to superphosphate responses in the savannah region. The following conclusions have been reached:

Surface samples

The total phosphorus in the soils is low by comparison with other parts of the world, but its distribution among the soil fractions is normal for slightly acid soils.

Soils developed over basic rocks have more total phosphorus, and a lower proportion of acid-soluble phosphorus than soils over quartzose rocks.

Forest soils have more total phosphorus and more phosphorus in each of the fractions than savannah soils.

The organic phosphorus content is closely related to the organic carbon content. The C/P ratio averages 233 in forest and 247 in savannah, and this is considerably higher than the world average. The N/P ratio of 21·6 in forest and 19·5 in savannah is similarly high.

The C/P ratio, unlike the C/N ratio, is not reduced when long-rested savannah soils are cropped.

Soluble phosphate applied in permanent fertilizer trials is found in the acid-soluble, the alkali-soluble and organic fractions. In comparison with the amounts of those fractions already present, the acidsoluble fraction increases most and the organic fraction least.

Profile samples

In thoroughly leached soils the acid-soluble phosphate decreases sharply, and the alkali-soluble inorganic phosphate rather more slowly with depth. In the forest total phosphorus is greatest in the surface, but in the savannah there is no consistent change with depth. The incompletely leached profiles differ in showing a sharp rise in the acid-soluble phosphorus and the total phosphorus in the subsoil. The level of organic phosphorus falls less than expected down the profile, and the C/P ratio, like the C/N ratio, decreases in the subsoil.

Details are given of the S/P follicle ratios of a number of British breeds of sheep. These are discussed in relation to the figures of different authors for other breeds. Figures are given for the incidence of fibre shedding and follicle abnormalities, and evidence is presented which suggests that, at any rate in British breeds, follicles are formed after birth and it is suggested that the number formed may be roughly constant in all breeds. There is an appendix describing statistical treatment of the question of follicle competition.

1. Five pairs of Suffolk twin lambs were used and one of each pair was injected twice daily with 2 mg. of a growth hormone preparation for 2 weeks.

2. Treatment was begun when they were between 3 and 4 weeks old, the total number of follicles in the Suffolk not being complete until 6 weeks old. Skin samples were taken at the beginning and end of the experiment.

3. It was found that in 0·25 sq. cm. of skin the total number of primary follicles was reduced from the beginning to end of the experiment in both control and treated groups, probably because of the expansion of skin area during that time. While the total number of secondary, ‘news’ and ‘plug’ follicles was also reduced in the control group, they were increased in the treated group.

4. Since the secondary to primary follicle ratio was 5·3:1 for the treated group as compared with 4·5:1 for the controls it is concluded that growth hormone increases the number of secondary follicles which develop during the early weeks of postnatal life.

1. Two factorial pot experiments with ryegrass grown on calcareous soils from adjacent long-term experiments on Hoosfield, Rothamsted, are described. The effects of the method of application of phosphate, of the amounts of saP tested and of the level of phosphate applied are discussed with special reference to the manurial history of the soils.

2. Yield and total phosphorus uptake by ryegrass were slightly greater in the early stages of growth when superphosphate was applied as a powder than when an equal amount of phosphate was applied in solution, but this effect disappeared in later cuts of grass. Total phosphorus uptake was not significantly altered by the levels of 32P tested, and yields were only significantly decreased at one sampling date in one experiment. Uptake of fertilizer phosphorus decreased and ‘A’ values increased, however, in both experiments at the higher rates of application of 32P.

3. The addition of fertilizer phosphorus, as superphosphate or monocalcium phosphate, increased the uptake of soil phosphorus by ryegrass on all soils on which there was a yield response to phosphate. The recovery of fertilizer phosphorus, estimated radiochemically, was less, therefore, than the increase in phosphorus uptake by the crop on the soils on which there was a yield response to phosphate fertilizers.

4. ‘A’ values were determined on all soils and were shown to be almost independent of two- and five-fold increases in the amount of labelled phosphate tested. ‘A’ values were related to the previous phosphate manuring of the soils and increased by about one-third of the difference in phosphate content on soils that had received heavy applications of superphosphate or farmyard manure over 50 years ago. The ‘A’ values of soils that had recently received superphosphate in the field decreased in 3 years by more than the amount of phosphate taken up by the crops. ‘A’ values of soils that received rock phosphate in the field were lower and did not decrease with time.

An investigation has been undertaken to study the apocrine gland population of the skin of the three indigenous breeds of cattle native to Northern Rhodesia, and a comparison made between them and the Africander.

It was found that the Angoni had the greatest density of glands/sq.cm. and that this density agreed closely with mean figures quoted for Bos indicus. The Barotse and the Tonga, both Sanga types, had significantly lower gland density, but were both significantly greater than the Africander which is a relict Zebu form.

Dowling's finding that the decrease in the density of the glands with age is due to the ‘spread’ of the constant number laid down at birth by the growth of the skin was confirmed.

A very close correlation between the density of the apocrine glands and the heat toleration coefficient was established.

From a consideration of previous work, it is concluded that the density of the apocrine gland population is only one of the factors concerned in the control of thermo-neutrality by cattle; in this there is some disagreement with the conclusions reached by Australian workers.

1. Three experiments were carried out in this study to investigate the effects of L-thyroxine on sheep and wool production. In the first experiment L-thyroxine was orally administered to ewe lambs from weaning time for a period of 48 weeks. In the second experiment, ten uniform yearling ewes were selected and were randomly distributed into two groups of five; one group was fed daily 7 mg. L-thyroxine per ewe for 7 weeks from 1 April 1954. In the third experiment L-thryoxine was fed as a supplement to lactating ewes over the second to the sixteenth week of lactation at the rate of 7 mg. daily per ewe.

2. Differences in both body weight and rectal temperature between the experimental and control groups were not statistically significant. The treatment had also no effect on the body weight of the ewes during lactation.

3. Wool growth, as measured by the weight of keratine production per unit of surface area, was increased significantly during the period of thyroid treatment. This increase in wool production was due to an increase in the length of the wool fibres but not to any observable increase in the diameter of the fibres. This effect is different from that produced by a high plane of nutrition where extra wool production is characterized by increase in both length and diameter.

4. It was observed that the treated ewes exhibited hypersexual activities characteristic of male behaviour, i.e. jumping and mounting other animals.

5. There was a significant increase in the rate of milk secretion over the period. 2–8 weeks. This increase was reflected in an improved live-weight increase of the lambs which were suckling these treated ewes. The difference in milk yield between treated and untreated ewes was not maintained over the nine to ten weeks period of the lactation.

6. As a result of these studies it has been established that the normal milking performance of Border Leicester × Scotch Blackface ewes is high as compared with that of other breeds or crosses reported in the literature. The shape of their lactation curve suggests, however, that it is possible that after the eighth week of lactation the ewes may become competitors with their lambs for available grazing. Expressed in another way ewes become less efficient as converters of their food into milk for lambs, for which milk is becoming proportionately a less important component of the diet. This finding raises the question of the possibilities of providing creep grazing or supplementary feeding for lambs so that their growth potential is fully realized. Alternatively, there may, under farm conditions, be grounds for weaning lambs at about 12 weeks so that they may have preferential treatment in regard to available grazing rather than to adopt customary weaning at about 16–18 weeks of age.

7. It has been established that a close relationship exists between the milk yield of dams and the growth, rate of their lambs under normal grazing conditions. Because of this strong relationship a regression formula has been tentatively advanced which may permit workers to select ewes for milk yield on the basis of the live-weight gain of their lambs.

A study of the climate within the maize-growing areas of the West Rift area of the Kenya Highlands showed that rainfall is the major meteorological variable.

A further investigation showed that average yields of maize in subdistricts within the region are markedly affected by changes in seasonal rainfall and are apparently unaffected by large changes in acreage planted from year to year over a period of eleven years.

1. In five experiments, groups of milking cows were changed abruptly from winter-stall feeding to graze a number of different swards, and changes in the concentration of blood-serum magnesium and of other blood constituents have been studied.

2. Wide variations in the severity of hypomagnesaemia in individual cattle were found in all experimental groups, due possibly to such factors as individual variations in the intake of herbage, the requirement and body reserves of magnesium and the capacity to absorb magnesium from the gut.

3. The degree of hypomagnesaemia observed was independent of the level of milk production, but was generally less severe in Friesian than in Shorthorn and Guernsey cattle. The onset of hypomagnesaemia was delayed for a few days in cattle with a high serum-magnesium concentration at the commencement of grazing.

4. In two out of three experiments in which the effect of fertilizer treatment was studied, the incidence and severity of hypomagnesaemia was increased by the application to the sward of heavy dressings of nitrogenous fertilizer. In the third experiment, severe hypomagnesaemia occurred on a plot which had received no nitrogen fertilizer, due, it is thought, to a restricted intake of herbage magnesium, since the sward was extremely sparse. The feeding of supplements of flaked maize, crushed barley, crushed dredge corn, molassed sugar-beet pulp or a concentrate mixture balanced for milk production, to grazing cattle did not reduce the incidence of hypomagnesaemia.

5. The cutting of grass and feeding it in the stall did not prevent the development of hypomagnesaemia.

6. Blood pH and the concentrations of bloodserum calcium, sodium, potassium and blood glucose in cattle were unaffected by a change from winter feed to spring grazing, but a marked change in blood-serum non-protein and urea nitrogen and blood ammonia nitrogen, but not in any other nitrogenous constituents of the serum, was observed. The concentrations of serum non-protein and urea nitrogen and blood ammonia nitrogen were highest in groups of cattle grazing swards which had received a heavy dressing of nitrogen fertilizer and had a high nitrogen content.

7. In the two experiments in which the severity of hypomagnesaemia was increased by the application of nitrogenous fertilizer, there was a close group association between high concentrations of blood serum non-protein and urea nitrogen and blood ammonia and low concentrations of blood-serum magnesium. High levels of serum urea and blood ammonia during grazing are thought to reflect a high ammonia production in the gut, which may be responsible for the disturbance in magnesium metabolism which produces hypomagnesaemia.

The distance between the front of the incisor teeth and the front of the maxillary pad (incisor bite measure) was measured in 140 sheep about 1 year old. The sheep consisted of seven breed types—the offspring of Blackface ewes by Wiltshire, Border Leicester, Lincoln and Blackface rams, and of Welsh ewes by Welsh, Wiltshire and Suffolk rams. Within each breed type the effects of four different feeding treatments lasting 7 months were studied. These produced small but very significant differences in bite measure. Differences between breed types were significant only in respect of the division between the two breeds of dam. Effect of breed of dam, however, was confounded with any effect due to differences in origin.

The proportion of permanent central incisors which had replaced milk teeth when the animals averaged a little more than a year old was affected both by the level of treatment during the experiment and by breed.

Groups of pigs were weaned at 8, 14 and 20 lb. live weight from each of seven litters. Each of the twenty-one groups was housed separately and selffed a 30% protein diet ‘A’ up to 25 lb. live weight.

From then until 56 days of age each group was selffed a 22% protein diet ‘B’.

Weight at weaning had no significant effect on age at 40 lb. live weight, but weights at 56 day old of 46·5, 50·2 and 47·7 lb. for pigs weaned at 8, 14 and 20 lb. respectively tended to favour weaning at 14 lb. (P < 0·10).

Pigs weaned at 8, 14 and 20 lb. each required 25, 16 and 6 lb. respectively of expensive diet ‘A’ to reach 25 lb. live weight. To grow from 25 to 40 lb. live weight they each required 30, 28 and 27 lb. of diet B, and this trend in favour of the pigs weaned at heavier weights was significant at P < 0·05.

These results are discussed in relation to the system of early weaning.

An experiment was carried out to compare the amount of milk obtained by lambs suckling at 1-hourly intervals with that obtained by lambs suckling at 4-hourly intervals during a 24 hr. period. Statistical analyses of the figures showed that the milk consumption of lambs suckling at 4-hourly intervals was not greater than that of lambs suckling at 1-hourly intervals.

1. A study has been made of the production of volatile fatty acids obtainable from dried grass and its gross water-soluble and water-insoluble separates, in the artificial rumen, over two growing seasons.

2. In contradistinction to fresh grass, the dried grass gives a consistent production of acetic acid proportionately greater than propionic acid, at all stages of maturity, but when aqueous extracts of the dried grass, and the resultant extracted grass, respectively, are examined separately in the artificial rumen, it is found that the former yield preponderating amounts of acetic acid while the latter give amounts of propionic acid equal to, or exceeding, the corresponding productions of acetic acid.

3. An examination of the titration curves for the total acids obtained from the dried grass, extracted grass and grass extract runs, indicates an approach to an incomplete relationship between the residual carbohydrate in the extracted grass and cellulose, while the grass extract reveals itself as the chief source of acetic acid in the whole dried grass, the acid being formed very speedily at the start of the run.

4. The suggested sources and some of the possible metabolic pathways involved in the formation of v.f.a. from grass are discussed in the text.

1. Pot culture experiments are described comparing the recovery of nitrogen, and sulphur by the difference and ‘labelled atom’ methods and the recovery of carbon by the latter method. Italian ryegrass was used as the test crop with ammonium sulphate, calcium nitrate and urea as the fertilizers.

2. The recovery of fertilizer nitrogen was less using the ‘labelled atom’ technique than the conventional difference method.

3. The recovery of sulphur from ammonium sulphate ‘labelled’ with 35S was measured. It was considerably less than the nitrogen, but not inconsiderable especially as a basal dressing of ‘unlabelled’ K2SO4 was applied.

4. Using urea ‘labelled’ with 13C there was no evidence that any of the carbon was in the ryegrass four weeks after application.

1. The main experiment described was a 4 × 2 factorial designed to test levels of 18, 21, 25 and 28% crude protein in diets fed from 25–50 lb. live weight and to compare an all-vegetable diet with one containing white fish meal for pigs of 50–100 lb. live weight.

Forty-eight pigs were used in the experiment. They were weaned at an average weight of 9 lb. and were fed a standard 29% protein diet until they each weighed 25 lb. Between 100 lb. and slaughter at 200 lb. they were fed a standard all-vegetable diet containing 14% protein.

Live weights and food-consumption figures for each pig were recorded throughout the experiment and carcass-quality measurements were taken.

2. Forpigs of 25–50 lb. there was no advantage in raising the level of crude protein above 18% in a diet based on white fish meal, dried skim milk, rolled oat groats, ground barley and fine millers' offals. Level of protein fed during this stage of the experiment did not affect performance at any subsequent stage, nor did it affect carcass quality.

3. For pigs of 50–100 lb. rates of live-weight increase and food-conversion efficiency were poorer by 13 and 14%, respectively, on an all-vegetable diet containing 17% crude protein than on a diet including 7·5% white fish meal and containing 15% crude protein. This difference was not affected by level of protein fed before 50 lb., and in its turn it did not affect either growth performance from 100–200 lb. or carcass quality measurements.

4. The following notes relate to the overall performance of early weaned pigs during this experiment: After being weaned at an average of 9 lb. when 10 days old, the pigs reached 25 lb. at 36 days old and 50 lb. at 58 days old. They each ate an average of 29 lb. of the 29% protein diet 1A and 59 lb. of the diets 2 A–D fed from 25–50 lb. Between 50 and 200 lb. food-conversion efficiencies were lower than is usual for individually fed pigs at the Rowett Institute, but rates of live-weight increase were satisfactory when considered in relation to the plane of feeding followed, and the average age at 200 lb. was 185 days. Of the carcasses 85% graded A.

5. In a pilot trial pigs were changed over from the 29% protein diet 1A to the 18% protein diet 2D at 13, 17, 21 or 25 lb. live weight.

There was a linear trend towards slower rates of live-weight increase as the weight at change-over was reduced, and pigs changed at 13 lb. took 7 days longer than those changed at 25 lb. to reach 40 lb. live weight. Overall food-conversion efficiency was best when the change was made at 25 lb., but because of the high cost of diet 1 A in relation to diet 2 D there was a linear trend for the total cost of food per pig to be lower as the weight at change-over was reduced.

6. The results of the pilot trial were discussed in relation to the effects on the lightest pigs in a group of changing to diet 2 D as the average weight per pig reached 25 lb.

1. Measurements of volume, sperm density, ergothioneine, sulphydryl groups and citric acid were made in 100 ‘tail-end samples’ (post-coital penis drips) from thirteen thoroughbred stallions. In addition, a few analyses were made of postcoital vaginal samples.

2. The ‘tail-end samples’ were found to differ substantially in their composition from that of the whole ejaculates. They lacked the characteristic gelatinous appearance of normal stallion semen, and had a much lower content of spermatozoa, ergothioneine (sulphydryl groups) and citric acid than an average stallion ejaculate.

3. As the variations in volume and composition of the ‘tail-end samples’ collected from different stallions or from the same stallion on different occasions were considerable, it is unlikely that prognostication of fertility could be usefully based on results obtained by analysis of such samples.