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.

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.

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 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. The findings presented in two previous papers on the yields of volatile fatty acids, obtained by the action of rumen liquor in the artificial rumen, from fresh grass, dried grass and the water-soluble and water-insoluble separates of the latter, have been amplified by a consideration of the acids similarly obtained from specimens of chemically prepared crude fibre and cellulose, from four of the dried grass specimens.

2. The proportions of different volatile fatty acids from grass crude fibre and grass cellulose resemble those obtained from cellulose powder, propionic acid being produced in greatest relative yield.

3. A general review of these latter findings, in relation to those already presented, has been given.

1. One hundred and sixty-eight pigs were used in four experiments to test the value of including antibiotics and copper sulphate, either as separate supplements or together in rations for growing pigs. Procaine penicillin was added at the rate of 5·36 mg./lb. diet and Aureomycin (in Aurofac 2 A) at 8·03mg/lb. and CuSO4. 5H2O as 0·1% of the diet.

2. During the growing period in Exp. 1, pigs fed diets supplemented with copper sulphate or procaine penicillin grew 9 and 3% faster respectively than the controls. Pigs fed a diet containing both supplements grew 22% faster than the controls. During the finishing period there was an outbreak of virus pneumonia and the within-treatment variability was large. There were no significant differences between treatments during this period, although pigs fed the supplemented diets tended to grow more slowly than the controls. Over the total experimental period pigs fed the diet supplemented only with copper sulphate grow 2% faster than the controls, and those fed the diet supplemented with both procaine penicillin and copper sulphate grew 4% faster than the controls, but these small average improvements were not statistically significant. In Exp. 1 treatment differences in food conversion efficiencies paralleled those for growth rates. Killing-out percentages were higher when pigs were fed the copper-supplemented diets, and lower when procaine penicillin was fed. The area of ‘eye’ muscle was increased by adding procaine penicillin to the diet.

3. During the growing period in Exp. 2, pigs fed diets supplemented with copper sulphate or with both procaine penicillin and copper sulphate grew 8 and 9% faster, respectively, than the controls. The addition of procaine penicillin had no significant effect when added as a single supplement or in conjunction with copper sulphate. During the finishing period pigs fed diets supplemented with copper sulphate, procaine penicillin, or both copper sulphate and procaine penicillin grew 5, 3 and 10% faster, respectively, than the controls, while over the total experimental period they grew 4, 0 and 9% faster, respectively.

4. Some pigs fed the copper-supplemented diets during the growing period in Exp. 2 were fed diets with no copper added over the finishing period. During this latter period the pigs grew at about the same speed as the controls, and significantly more slowly than those pigs which continued to receive copper sulphate. Thus, the average growth rates over the total experimental period were significantly slower by 3–7% when copper was omitted after 100 lb. than when it was fed to the pigs throughout the entire experiment.

5. In Exp. 2, as in Exp. 1, treatment differences in efficiency of food conversion paralleled those for growth rates. A higher rate of growth was always accompanied by an improvement in efficiency of food conversion, with about the same percentage difference between treatments. Indeed, changes in rate of growth were probably dependent upon changes in efficiency of food conversion, since all pigs were fed to the same scale based on live weight.

6. The treatment differences in killing-out percentage and area of eye muscle observed in Exp. 1 were not confirmed in Exp. 2. There were no differences in carcass quality measurements attributable to the treatments imposed in Exp. 2.

7. The livers of pigs fed diets containing copper sulphate during both the growing and finishing periods had, on average, about eighteen times the concentration of copper found in the controls. When the copper sulphate supplement was fed only during the growing period the liver copper concentrations were, on average, about four times those of the controls. However, the variation between the individual values was very large in all groups fed copper sulphate. This variation may have been caused partly by sampling errors if copper is not distributed evenly throughout the liver.

1. The aim of the experiment was to determine gross efficiency and net efficiency of energy conversion for milk production in lactating sows.

2. Two lactating Wessex Saddleback sows were used for both determinations. Two dry, non-pregnant sows of the same breed were also required for the determinations of net efficiency.

3. Rations were adjusted with the aim of maintaining the sows at constant live weight, but this was only partially successful.

4. Digestible energy intakes and milk energy outputs were measured during three 6-day recording periods in the 2nd, 5th and 8th weeks of lactation. Digestible energy consumed was determined by incorporating 1% of chromic oxide in the rations to be fed, and measuring the energy contents of food and faeces by bomb calorimetry.

Milk energy output was determined by measuring milk yields and compositions and calculating the energy contents from percentages of fat, protein and lactose. Milk yields were measured by weighing the young pigs before and after each suckling during each recording period, and samples were obtained by a special milking machine for determination of chemical composition.

5. Data required for the calculation of energy conversion efficiencies for milk production are presented. Gross efficiency was determined as approximately 45% and net efficiency as approximately 85%, but this latter value must be regarded more as an estimation because of the difficulty of determining accurately the maintenance requirements of lactating sows.

The role of the skin of cattle in heat toleration has exercised many and has produced almost as manyopinions as workers. Brody (1945) pointed out that tropical cattle had a considerably larger surface area than the temperate breeds due to the looseness and folding of the skin. Bonsma, van Marle & Hofmeyr (1953) suggested on the basis of work on the Africander that a thick skin was necessary, presumably to repel the heat rays. Other workers have laid stress upon hair colour and thickness of coat, together with skin pigmentation. Worstell & Brody (1953) considered that cattle do not sweat, but Dowling (1955 a, b) found evidence that they did.

During recent years increasing use has been made of carcass measurements to assess differences in the conformation, growth rates and carcass quality of bacon pigs. The measurements usually taken are: (a) thickness of back fat at one or more points, (b) thickness of flank at one or more points, and (c) the length of the carcass. Whilst at present there is fairly general agreement as to where the back-fat and flank measurements should be taken, the same agreement is not found in the case of carcass length.

1. A diluter for semen containing egg yolk, glycine, sodium citrate, fructose and glycerol is described.

2. 2005 inseminations gave an over-all conception rate of 65·7% (90–120 days non-returns) after periods of storage varying from 24 to 196 hr.

3. 401 inseminations after storage for 24–48 hr. gave a conception rate of 75·3%, compared with a conception rate of 60·0% on 398 inseminations after 96–144 hr. storage, using semen from the samecollections.

4. A possible use for modified glycine diluters for nominated service at A.I. centres is suggested.

1. The live-weight gain of lambs initially infected at five different levels was compared with that of similar but worm-free animals, under conditions of set-stocking at a high rate per acre.

2. Over a period of 9 months the worm-free controls gained 67·7% more weight than the total infected group, but the live-weight gains of the five levels did not appear to be related to their original infection or to their egg counts.

3. Although a few nematode eggs were detected in the faeces of some control lambs, reinfection was negligible under the conditions of this experiment.

4. It was concluded that a marked depression of productivity may be associated with an egg count as low as 114 e.p.g. in sheep 4–7 months of age.

1. The results of five experiments, comparing the wool production of worm free and infected sheep, are described.

2. Worm-free sheep produced (a) 12·0–38·8% higher total fleece weights and (b) 17·2–43·2% more clean, dry wool per unit area than infected sheep. None of the infestations was higher than occurs naturally in the field, but the greatest effects were associated with a low level of nutrition.

3. It is suggested that the precise effect of worm infestation on wool production will depend upon the age of the host when first infected, the size of the infestation and the rate of wool growth at the time when the infestation is at maximum.

1. Lucerne seed samples of known harvest history were treated by dry heat at various temperatures and durations; their germination capacity, emergence and establishment were tested by laboratory, greenhouse and field establishment tests on heavy Boil during 1952–6 at Cambridge.

2. A successful and safe heat treatment was 42° C. for 5 days, increasing the germination by as much as 44% up to about 90% at the cost of hard seed.

3. The establishment obtained on heavy soil from treated seed samples, although varying from season to season, was significantly higher (P > 0·001) at all seed rates than that obtained from untreated control samples.

4. Significant differences were obtained in germination capacity and establishment between samples harvested at different conditions. High moisture content of seed and high percentage of dark brown seeds was associated with late harvest. Brown seeds had a significantly lower germination capacity than yellow seeds. Only samples with a high initial moisture and high percentage of brown seeds showed a substantial decrease in germination capacity during the storage period of 3 years.

5. Although the mean number of plants established is significantly higher for higher seed rates the mean percentage of plants established decreases significantly with higher seed rates and the greatest wastage of seeds occurred at the high seed rate of 15 lb; per acre.

6. The viability of seed and speed of germination and of emergence were the most important factors in determining the successful establishment of a crop on heavy soil.

7. Hard seed is viable and could germinate and produce seedlings by the end of the season, but only a very small percentage of it could normally be established under field conditions. With untreated seed no significant correlations were established between laboratory germination and field establishment or between laboratory germination and greenhouse emergence, yet there were highly significant correlations in these cases for treated seed. With increased duration of laboratory germination test, corresponding to a decrease in the proportion of hard seed, values of r increased. Correlations between field establishment at three seed rates and greenhouse emergence were significant in the case of both untreated and treated seeds.

8. When the hard seeds were added to germination or establishment the relationships between the results of these tests were very close and highly significant correlations were established for both lots of seed, untreated and treated. The high proportion of hard seeds was the main limiting factor preventing a close relation between tests for untreated seed.

1. The diploid species Secale cereale (2n= 14) is self-incompatible, Aegilops longissima (2n = 14) and A. caudata (2n = 14) are self-compatible. A. longissitna is usually self-pollinated and A. caudata is usually out-pollinated.

2. Meiotic behaviour, constancy of chromosome number and seed fertility have been examined in the three octoploid amphidiploids derived from crosses of Triticum vulgare variety Holdfast (2n = 42) with S. cereale A. longissima and A. caudata respectively.

3. All the amphidiploids had cells in which some chromosomes were unpaired at first metaphase of meiosis. This meiotic irregularity is not, therefore, related to the breeding system of the diploid parent.

4. The fertility of the amphidiploids was not related to their meiotic regularity.

5. The least fertile amphidiploid was derived from the self-incompatible diploid S. cereale. The most fertile amphidiploid was derived from the selfcompatible, self-pollinating diploid, A. longissima.

6. It is suggested that the infertility of the wheatrye amphidiploid may result from interactions between genotypes adapted to different breeding systems, rather than from the homozygosity in the amphidiploid of deleterious recessive genes derived from the outbreeding rye parent.

7. The demonstration of the independence of meiotic regularity and fertility will complicate selection work on wheat-rye amphidiploid material.

1. A series of experiments designed to compare the effects on the succeeding wheat crop of five different methods of treating the aftermath of a Broad Red Clover ley is described and the results discussed.

2. There was little consistent difference in the effects of using the second crop for hay, for grazing or for green manure by ploughing it in. Bastard fallowing immediately after the first hay crop and taking the second crop for seed both showed large seasonal fluctuations in their effects, but there was insufficient evidence to show if these were due to seed-bed differences.

3. In no season was taking the second crop for hay outyielded by any other treatment.