1. Honey-bee colonies were fed either concentrated or dilute sugar syrup, or remained unfed, in spring, summer, and autumn of 1958 and 1959.

2. More concentrated than dilute syrup was accepted in every experiment, but the proportion of concentrated to dilute syrup accepted decreased during the course of both years.

3. The concentration of syrup fed made no apparent difference to the gain in weight relative to the sugar taken, probably because the greater efficiency in storing concentrated syrup was offset by the diminution in foraging produced.

4. Feeding dilute or concentrated syrup increased brood rearing during and after feeding in one year (bad weather) but had no effect on brood rearing in the other year (good weather).

5. While being fed colonies usually collected more pollen than they otherwise would.

6. Feeding either concentration of syrup probably decreased nectar gathering when foraging conditions were good, and concentrated syrup may have decreased it more than dilute syrup.

1. Worker bees learnt the colour of their hive in the close vicinity to their hive entrance and took little or no notice of colours above the lower brood chamber. They orientated to a colour below the entrance more than to a colour above. They did not learn combinations of colours.

2. They distinguished between certain symbols placed immediately above the hive entrance.

3. They learnt the height of their hive and the height of its entrance above ground.

4. More worker bees and drones from queenright colonies drifted to queenless than to queenright colonies. Drones expelled from queenright colonies did not drift to queenless colonies.

The influence of undersowing on the establishment of broad red clover and Italian rye-grass was investigated under three managements and two levels of nitrogen applied in spring. The following conclusions are drawn:

1. The cereal cover crop reduced the aggressiveness of Italian rye-grass towards red clover.

2. The cereal cover crop produced a high initial yield of dry matter and crude protein. In midseason, when keep from maiden seeds is important, the highest yield was obtained in the absence of the cereal cover crop.

3. The danger of failure in the take of undersown herbage seeds is increased when soil moisture is very low.

4. Total dry-matter yield in the seeding year was increased by using a cover crop, but starch-equivalent yield was not greatly affected. Crude-protein production was increased when the cover crop was cut for silage or frequently grazed, but not when a grain crop was harvested.

5. Undersowing Italian rye-grass and clover gave a higher yield of dry matter, starch equivalent and crude protein than sowing the herbage after the cereal was harvested.

6. The cover crop depressed weed growth, and ‘Nitro-Chalk’ increased it, except where Italian rye-grass was undersown.

7. The application of ‘Nitro-Chalk’ increased the yield of dry matter, particularly early in the seeding year. ‘Nitro-Chalk’ encouraged the growth of Italian rye-grass and oats but depressed the clover. This reduction in legume yield was least when defoliation was frequent. The influence of nitrogen on plant growth was especially noticeable when soil moisture was low and a cover crop used.

1. Fifty-four dairy type calves were grazed together on a perennial-type pasture. At regular intervals from birth to 17 weeks individuals were slaughtered and the weights of their reticulorumens, omasums and abomasums were immediately recorded.

2. The recitulo-rumen had the fastest growth rate of the organs of the stomach and the abomasum had the slowest.

3. During the first few weeks after birth, the four stomachs altered rapidly in proportion to the live weight of the calf. By 17 weeks of age, the reticulo-rumen apparently had not reached a constant weight relative to live weight.

4. As a percentage of the total weight of the three organs, the reticulo-rumen reached a relatively constant proportion by about 8 weeks of age.

1. Two experiments were conducted to study the development of rumen function in young dairy calves under different feeding regimes.

2. The volume of the rumen contents increased with age whereas the volume of the abomasum contents tended to remain constant.

3. The concentration of total volatile fatty acids in the rumen liquor of milk-fed calves with free access to pasture reached constant levels at 5 weeks of age. Restricting calves to an all milk diet delayed the development of adult levels of volatile fatty acids until such time as roughage became available.

4. Levels of rumen ammonia were high soon after birth but showed a decline with age. An absence of roughage in the diet tended to maintain higher levels of rumen ammonia.

5. The pH of rumen liquor showed a steady increase from birth to 17 weeks of age.

6. Both volatile fatty acid and ammonia levels in the rumen showed a characteristic diurnal pattern of variation.

7. High figures for the digestibility of pasture by young calves were obtained. When calves which had been restricted to an all milk diet were offered roughage they quickly attained a digestive efficiency comparable with calves which had access to pasture from birth.

An attempt to find the effect of humidity on hatchability and at the same time indicate the optimum humidity for incubation was carried out by subjecting eggs in one incubator to various levels of humidity and comparing the results with eggs hatched as a Control in a second incubator of identical design.

Hatchability was depressed by excessively high levels of humidity but in general satisfactory hatches can be obtained between 40 and 70% R.H.

The pattern of mortality, the incidence of Malposition I but not Malpositions II, III and VI were affected by humidity level.

The optimum level found, c. 50% R.H., was lower than the previously accepted optimum and may be accounted for by a number of factors including egg size.

Eggs from Light Sussex hens were weighed before incubation started and on the 19th day of incubation to determine weight loss when incubated at 40% B.H. compared with 70% R.H. They were allowed to hatch and the day-old chicks were weighed.

Although the eggs incubated in the drier atmosphere lost more weight, their hatchability was no less than the eggs incubated in the wetter atmosphere. The hatched live weight of the chicks from the respective groups did not differ significantly.

The comparatively good hatch obtained here and in part I at the 40% R.H. is suggested as being an indication that for optimum hatchability large eggs may require lower humidity than small eggs.

Investigations on the effect of seed rates and cutting treatments on the inflorescence formations and yield of seed were carried out on S. 100, S. 184 and Kent wild white clover during 1957–60 at Cambridge. The study of primordial development under field conditions, establishment of the major characters contributing to the final yield and the factors affecting their contribution were the main object of these investigations.

These factors and their relationship and contribution to the final yield results are discussed in some detail.

A muscle biopsy technique was employed in an experiment designed to assess the effects of hexoestrol implantation on 2-year-old and 6-year-old Aberdeen Angus steers under New Zealand grazing conditions. This paper reports the results concerning live-weight gains, carcass weights and detailed analyses of samples of m. semitendinosus and associated subcutaneous fat.

There was some evidence of an adverse effect of the biopsy operation on the older, less tractable, animals, despite the observation of no apparent effect of repeated muscle biopsies in a preliminary trial with sheep.

Hexoestrol implantation, of four 15 mg. pellets for the 2-year-old steers and six 15 mg. pellets for the 6-year-olds, led to significant increases in live weight gains during the later part of the trial only, and reduced the dressing-out percentage of the younger animals. Although there were indications of a positive response in carcass weight to hexoestrol implantation, it was concluded that, under the conditions of this experiment, implantation of relatively large dosages was not economically justified in terms of increased meat production.

Absorption of the implanted pellets varied from 42 to 85% of the total dosage, but evidenced little association with live weight changes.

Deposition of subcutaneous fat appeared to be reduced under the hormone treatment, but the responses in this respect of the 6-year-old steers were highly variable.

1. In an experiment designed to study some of the factors influencing the role of clover in grassclover swards fertilized with nitrogen at different rates, botanical studies of the sward were made each spring and autumn. The methods used, and the results obtained in the autumn studies, are described in this paper.

2. Full details of the experimental treatments and design, and the yield results have been reported previously.

3. The botanical composition of the sward depended to a far greater extent on the variety of grass than it did on the variety of clover included in the seeds mixture. This was true also of the yields from the different swards.

4. Some relationships are suggested between the yield and nitrogen response results and the variations in the botanical composition of the sward attributable to the variety of grass included in the seeds mixture.

5. Kersey white clover appeared to be more persistent than S. 184 and S. 100 where fertilizer nitrogen was applied to the sward, although no differences in persistency were noted in the absence of applied nitrogen.

6. A statistical study of the botanical data obtained indicated that the intensity of sampling employed gave the optimum balance between variance and time expenditure, since only a slight reduction in variance would have been obtained if double the number of samples had been taken.

The results of the grassland experiments show that as a straight nitrogen fertilizer urea was, on average, slightly less effective than the conventional materials. In the majority of individual experiments there was no significant difference between the yields from urea and those from ‘Nitro-Chalk’; on the other hand, in a very few experiments the urea yields were much lower. The arithmetic means of the averages in each series of grassland experiments indicate that urea gave total yields about 93% of those from ‘Nitro-Chalk’ and the average response (i.e. difference from control) from urea was about 85% of that from ‘Nitro-Chalk’.

The available data for cereals are considerably less than for grassland but here again there is an indication of the infrequent slightly lower efficiency of urea.

On kale the results are confusing. At times urea was safe but in one experiment heavy dressings incorporated in the seed-bed caused serious damage.

1. An experiment was conducted at Jealott's Hill from 1945 to 1956 to study yield trends of cereals grown continuously and in four-course rotations including 1-year ‘renovation’ treatments in the form of (a) grazed ley, (b) ley cut for hay and grazed, (c) rape grazed, (d) mustard for green manure, (e) fallow.

Winter wheat, spring oats and spring barley were successive test crops common to all rotations and followed the ‘renovations’ or spring barley in the corresponding phase of the continuous cereals system. Main plot (rotation) comparisons were confounded with two levels of nitrogen fertilizer (0·2 and 0·4 cwt. N/acre) and three straw treatments (straw removed, burned or ploughed in) which were applied to all three cereal test crops.

All plots except those in fallow received 0·3 cwt. P2O5 and 0·3 cwt. K2O/acre every year. From 1945–48, leys, rape and mustard received 0·2cwt. fertilizer N/acre; from 1949 this dressing was doubled.

Grazing of leys and rape was by sheep.

2. In the earlier years the highest yields of wheat were obtained in the rotations containing rape, mustard or fallow, but in the later years yields after leys were superior to those in all other rotations. Wheat yields in the continuous cereals rotation soon declined and remained at the lowest level throughout, due largely to severe incidence of ‘take-all’ disease.

In the later years yields of barley and oats following 1-year ley were also superior to those in all other rotations.

3. In the six cropping rotations compared, all three cereal crops showed very marked responses to applied fertilizer nitrogen, particularly in the later years as the natural fertility of the site declined.

A laboratory and pot-culture investigation to seek reasons for the variable response of grass and other crops to top-dressings of urea, and to the occasional phytotoxicity to seedlings of urea either mixed in the soil or drilled in contact with the seeds is described.

The part played by biuret, the chief impurity in commercial urea, has been examined. It can be phytotoxic to germinating seedlings when in contact, but in the quantities likely to be applied in agriculture in top-dressings, e.g. 150 lb. of urea with up to 2·5% of biuret, its effect is negligible. Up to at least 5% of biuret can be present in urea without affecting its ammonification or nitrification in soil.

It has been shown that loss of nitrogen to the atmosphere can account for the poorer responses of grassland to top-dressings of urea as compared with ‘Nitro-Chalk’ or ammonium sulphate.

The phytotoxic behaviour of pure urea to germinating seeds seems to be due to rapid production of ammonia. This gas is also evolved from topdressings of urea. Both the phytotoxicity and the loss to the atmosphere can be reduced by mixing urea with acid salts to neutralize the ammonia.

1. A co-ordinated trial has been carried out at twenty-two centres to compare the value of wheat, crushed or ground, with that of fine wheat offal (weatings) when fed in equal amounts in the rations of growing pigs.

2. Pigs fed the wheat rations grew faster (8·7% improvement for crushed wheat, 6·3% for ground), had. more efficient food conversion (9·0 and 6·5%) and yielded heavier carcasses for a given final live weight (1·4 and 1·3%) than pigs fed weatings but were fatter at the shoulder (5·6 and 7·5%) and the loin (11·2 and 13·1%); all these effects were highly significant. Differences in length of carcass were not significant.

3. Improvements in growth rate and food conversion were significantly greater with crushed wheat than with ground wheat. None of the other differences between crushed wheat and ground wheat was significant.

4. An economic appraisal has been made which shows that, on the basis of certain assumptions, the feeding of wheat would have resulted in higher profit per year than the feeding of weatings under the price structure and system of grading prevailing during the period of the experiment.

5. Changes in the price structure (average price of bacon pigs, differentials between grades and cost of wheat and weatings), in the average quality of the carcasses (length of the carcass and fat at the shoulder and loin) and in the size of treatment effects on food conversion, all have a substantial effect on relative profits. The appraisal suggests, however, that feeding wheat would be more profitable than feeding weatings when the above changes were extremely severe.

1. A cross-bred sheep was fed successively with supplements of dried skim-milk or lactose. The effect of the supplements on the lactase activity of the rumen liquid was followed.

2. Lactase activity was expressed as mg. lactose hydrolysed per ml. rumen liquid, or per mg. protein nitrogen. The enzymic activity fluctuated considerably after a change in the diet, and did not become constant even when the ration remained the same for 7 weeks.

1. A total of twenty-one Merino lambs varying in age from 2 to 11 weeks were slaughtered.

2. The enzymic activity of their rumen contents was measured on a variety of carbohydrates and on protein.

3. Enzymic activity was expressed as mg. carbohydrate hydrolysed/mg. protein nitrogen/hour.

4. When compared with the rumen contents of adult sheep, lactase and proteolytic activity decreased with age; maltase, sucrase and fructanase activity increased; amylase activity decreased from 2 to 11 weeks though adult values were similar to those of the 2-week-old lamb.

5. The rumen contents of the lamb were as efficient as those of the adult sheep in their ability to hydrolyse a wide variety of carbohydrates and protein.

1. The study of the photoperiodic responses of varieties and forms of the genus Avena has revealed considerable diversity within the group.

2. The investigation of a number of forms differing in geographical distribution confirms the close relationship between photoperiodism and region of origin. There appears to exist a definite relationship between the geographic origin of a given form and the limits of its tolerance to short day. The forms from the more southerly latitudes suffered less from short day than those of northern origin.

3. Panicle exsertion was entirely suppressed under photoperiods of 12 hr. and less in A. sativa varieties Victory, S. 84 and Black Supreme, which have been selected for high yielding ability in more northerly latitudes.

4. Plants which failed to produce exserted panicles in varietal tests were dissected, and it was found that floral differentiation had not been inhibited by the shortened photoperiods, but that the full elongation of the internodes, especially the upper internodes, had been suppressed.

5. Selection experiments with progenies of the cross Wintok × A.fatna form Cc 3872 grown under different photoperiods confirmed a highly selective response to daylength, thus indicating that this response is under genetic control.