1.Within a flock of 55 Welsh Mountain ewes maintained under lowland conditions the first ewecame into oestrus on the 14th October. The mean cycle length of 44 normal cycles was 16 days 3 hr.

2. The onset of oestrus as assessed by the time of mounting of the ram does not appear to beevenly distributed throughout the day (24 hr.).

Six factorial experiments, each lasting 3 years, were carried out to determine the effects of N, P and K on herbage cut five times each year.

Clover almost disappeared with the 87 lb. N treatment and none survived with the 174and 348 lb. dressings. N increased the proportions of rye-grass and cocksfoot in the sward. P had no influence on botanical composition. K usually increased the clover content in the absence of, but had practically no effect in the presence of, N.

The performance of four varieties of lucerne, du Puits, Provence, Grimm and S 205, as spaced plants, in broadcast plots and in drills, with and without a companion grass was compared by yield of dry matter, percentage and yield of crude protein, leanness, weediness and reaction to leaf spot (Pseudopeziza medicaginis).

1. The influence of castration on meat production has been studied in three experiments involving cattle, sheep and pigs. The results are presented to indicate the changes which might be expected in more extensive experiments, and give an indication of the parameters likely to be important.

1. Ten experiments were carried out on winter wheat in various parts of England in 1959-61, to compare 60 lb./acre of nitrogen broadcast as ammonium sulphate, ammonium nitrate and calcium nitrate (a) all in autumn, (6) one-third in autumn and two-thirds in spring, (c) all in spring. The winter rainfall was high in four experiments and moderate in six.

1. The effects of seed size in the swede crop on germination, emergence, growth and final yield were studied during the period 1959 to 1962.

2. The germination percentage was similar for all sizes of seed, but the emergence percentage was slightly poorer for ‘large’ and ‘small’ seed than for ‘graded’ seed.

3. Leaf area in the early stages of growth was proportional to the seed size, but as the season advanced the plants from small seed grew at a relatively faster rate than those from large seed, so that at harvest the relative yield difference, although still in favour of large seed, was much smaller than the relative difference in seed weight or seedling leaf area. It was shown that the relatively faster growth rate from small seed was not due to a later onset of inter-plant competition.

1. The mean concentrations of sodium, potassium, phosphorus, calcium and magnesium were determined in the dry matter of the gut contents of European and Zebu steers which were allowed water ad lib. or in restricted quantities. Except for K concentrations in the colon and rectum, which were significantly higher in the Zebus, there were no breed differences.

1. A male-sterile winter bean, inherited as a simple Mendelian recessive, is described.

2. The sterility gene was shown to be expressed in the cytoplasm of eleven inbred lines of English winter beans, two varieties of English spring beans, six varieties of foreign spring beans and three varieties of broad beans (Vicia faba major). It is concluded that these varieties are unlikely to provide a fertility-inducing cytoplasm which would allow the development of a non-restoring pollinator.

3. Evidence of linkage between three chlorophyll-deficient mutants and the male sterility locus is given and circumstances are outlined by which a suitable marker gene could be employed to assist in large-scale production of hybrid seed.

1. Sodium, potassium, calcium, and magnesium balances in seven Hereford and seven Zebu steers have been determined during two 10-day trials. Values for phosphorus, omitting urine excretion, were also determined.

2. No breed differences were found apart from a tendency for Zebu steers to excrete less potassium in their faeces and more in their urine than Herefords.

A plot trial compared the herbage yields of Hyparrhenia veld and giant Rhodes grass (Ghloris gayana cultivar) cut at grazing and hay stages of growth at four levels of N fertilizer. Veld outyielded Rhodes grass in all treatments.

The milk yields from Hyparrhenia veld and a giant Rhodes grass pasture were similar when grazed at low and high stocking rates with and without N fertilizer.

1. F1 hybrids between inbred lines of winter beans were obtained by roguing male-fertile plants from segregating progenies of a genetic male-sterile line which had been interplanted with a pollinator.

2. In a series of trials the mean yields of many hybrids were significantly higher than those of open-pollinated varieties. Over the 4 years, 1959–62, with trials at three centres in each year, the mean advantages of all hybrids over the two control varieties was 6·4 cwt./acre over Gartons S.Q., 4·7 cwt./acre over Throws M.S.

1. Ten-day balances of sodium and potassium were recorded for Shorthorn and Zebu steers fed poor quality chaffed hay with and without sodium supplements.

2. Sodium supplementation had no appreciable effect on growth, all animals being close to amaintenance regime.

The distribution of whole blood potassium concentration in 1783 Welsh Mountain sheep showsmarked bimodality, varying about two modes, of 44 and 14 m-equiv./l.

The difference between high (HK) and low (LK) potassium types was not clear-cut. About 5 % of animals lay in the area where the tails of the two distributions merge.

Haematocrit values and plasma potassium concentrations were used to estimate erythrocyte potassium levels. They confirmed that the bimodality is due to variation within erythrocytes but did not offer a satisfactory method of allocating intermediate animals.

1. Sodium and potassium balances and the growth rate of steers have been recorded for animalsreceiving a protein supplement on a high and low salt regime.

2. Zebu steers receiving less than an average of 0-2 g. sodium per day were able to grow at 82 % of the rate of Zebu steers receiving salt supplement. Shorthorn steers under the same conditions grew at 72 % of the rate of Shorthorns receiving the supplement.

Little information is available on the composition of the milk of British breeds of sheep under conditions prevailing in this country.

1. This paper presents results of the analysis of milk from 46 Clun Forest ewes suckling lambs during 1961 and 1962. Three groups of ewes were used, two of which grazed while a third was fed indoors. Milk samples were obtained by handmilking one quarter while the lamb sucked theother, after a period of 5 hours during which suckling was prevented by means of udder covers.

1. Concentrations of ammonia, volatile fatty acids, and molar proportions of acetic, propionic and butyric acids were determined in the rumen liquor of sheep fed fresh herbage harvested in the first month of growth.

2. Concentrations ofammoniacal nitrogen ranged from 4·06 to 13·65 mg./1OO ml. rumen liquor with a mean value of 8·21.

3. Concentrations of volatile fatty acids ranged from 7·50 to 12·20 m-moles/100 ml. rumen liquor with a mean value of 9·81. Mean molar proportions of acids were: acetic 65·8%, propionic 19·5%, n-butyric 9·0 % and higher acids 5·7 %. Differences in the proportions of acids found at different sampling times were not statistically significant.

1. The increase in soil carbon has been assessed in arable land sown to different leys variously managed.

2. Under swards cut for herbage conservation, carbon in the top 15 cm. of soil increased by about 0-05 % each year. Although an increase of 0-3 % was found immediately under drills of cocksfoot grown for seed production, there was no increase midway between the drills and, for a given area of land, the carbon increment under such row-crops is probably similar to that under cut swards.

The use of changeover designs and of covariance analysis in experiments on lactating cows is reviewed. Continuous treatment designs are criticized because of their large coefficients ofvariation, e.g. of the order of 20 % for milk yield. Although changeover designs have smaller errors they are criticized because the results have strictly limited practical application. Covariance analysis applied to the data from continuous treatment designs offers a means of increasing their precision. Measurements made in a preliminary period may be used to adjust experimental measurements made subsequently for animal to animal variation. The covariance method was tested on data from thirtytwo heifers in an experiment involving factorial sequences of treatments. Weeks 5-12 of lactation formed the control period and weeks 13-22 the experimental period.

Results are given of 124 factorial experiments testing N, P and K fertilizers for maincrop potatoes; the experiments were done by N.A.A.S. Soil Chemists in the years 1955–61. The experimental sites were in sixteen groups, corresponding to particular soil series or complexes.

There were substantial differences in mean yield and in response to the lower levels of P and K between soil series; the influence of soil was less at higher rates of application. Alternative methods of soil classification which appeared to be associated with response were texture, experiments on the lighter-textured soils showing higher responses to K; and depth of freely drained soil, soils with impeded drainage being associated with larger P responses. Responses to P and K were particularly large on soils in Wales and N.W. Cumberland.

1. The contents of moisture, intramuscular fat and total nitrogen in various muscles of boars at 200 and 260 lb. live weight have been compared with corresponding data from hogs.

2. Although total nitrogen was higher and moisture and fat lower in the muscles of boars than those of hogs at 200 lb. live weight the converse tended to apply when comparisons were made at 260 lb.