Fifty-one Scottish Blackface ewes were divided into three groups and individually fed throughout the latter half of pregnancy: (I) in excess of their nutrient requirements, (II) to produce a uniformly moderate degree of undernourishment throughout the final 6 weeks of pregnancy, and (III) to produce a uniformly severe degree of undernourishment during the same period.

Marked differences were evident in the amounts of feed required to maintain the prescribed nutritional states, and within the undernourished groups, between ewes with single and twin foetuses. In both groups of undernourished ewes the amount of feed required to maintain the prescribed level of undernourishment during late pregnancy was strongly related (P < 0·001) to birth-weight. The additional nutrient requirement of the ewe in late pregnancy was estimated to be 100 g D.o.m./kg foetus/day.

1. Three groups of seven Southdown and seven medium wool Peppin Merino ewes were subjected, respectively, to seasons of daylength corresponding to a latitude of 60° S., reversed seasonal lighting (60° N.) and an equatorial daylength with reversed thermal seasons, for 2½ years. During the next 20 months group 1 continued as before. Group 2 had a 32-week photoperiodic year and group 3 had a 32-week thermal year with equatorial daylength.

1. Using blood plasma FFA and ketone values to assess the nutritional state of individual ewes, high (H), medium (M) and low (L) planes of nutrition were imposed on 3 groups of Blackface ewes during pregnancy. By this method, ewes bearing single or twin foetuses were equally well or severely undernourished within treatment groups. The effects of these planes of nutrition during pregnancy have been assessed in terms of milk production, lamb growth, and live-weight changes by the ewes duriug their subsequent lactation. Immediately after parturition all ewes were individually fed a pelleted food ad lib. and their voluntary food intakes recorded. From 5 weeks of age individual voluntary intakes of solid food by the lambs were also recorded. Because of insufficient pen accommodation group-M ewes and lambs were discarded after 5 weeks of lactation.

The indirect estimation of intake of grazing animals is usually made from faecal index regression equations. Faecal nitrogen content or total faecal nitrogen are widely used to estimate intake. The most precise estimate of intake is obtained for a specific herbage (e.g. Phalaris) and condition (e.g. green, dry, etc,). Lambourne & Reardon (1963) found that the standard error of an estimate of the intake of a single animal, from a general regression equation, was 23%. Arnold & Dudzinski (1963) showed that the precision of estimates from general equations is improved by multiple regression including terms for faecal output. However, as regression relations are obtained from pen-feeding trials and are applied to field grazing, the following discrepancies axe likely to occur. We may have to extrapolate from low intakes in pens to higher intakes in the field; in addition selective grazing in the field can introduce a serious bias. To overcome the latter, when we are not sure about the exact condition of the forage eaten, as when green and dry herbage are both present, an average regression over two or more conditions has to be used. Naturally the precision of estimate then is much lower, because of the uncertainty as to what the animals are in fact selecting.

1. Emergence and dry-matter production of largeand small seeds of two varieties of broad beans (Beladi and Rebaya 34) were studied.

1. The mean iodine values and melting points of the fats from 16-month-old Romney wethers grazed on different pasture species including: perennial ryegrass or short-rotation ryegrass alone or admixed with white clover were as follows perinephric, i.v. 41.3-46.1, M.P. 47.7-49.4°C; omental, i.v. 43.2-47.4, M.P. 46.6-47.4°C; subcutaneous, i.v. 46.4-50.4, M.P. 44.2-46.0°C and 1. dorsi muscle, i.v. 57.5-60.3, M.P. 39.7-41.5°C. The iodine values were several units higher than those obtained previously (Shorland etal. 1962) for corresponding fats from mature Romney ewes.

The introduction of resistance to eyespot (Cercosporella herpotrichoides) from Aegilops ventricosa to Triticum aestivum is described.

In the hybrids, amphiploids and in the amphiploid derivatives investigated, the eyespot resistance was apparently simply inherited. Furthermore, this character was controlled by a chromosome, or chromosomes of the D genome of Ae. ventricosa and thus could be introduced into T. aestivum by recombination.

A study of fibre-type arrays in relation to kemp succession in Kerry, Cheviot-cross and Swaledale lambs has been carried out. It is found that:

1. There is a general association between HH grade and array such that higher grades tend to have stronger arrays.

Two degrees of compaction, 'heavy' with a flattyred vehicle wheel, and 'light' with a ring roller, were given to the seed beds after sowing barley and globe beet on three contrasted soils. Changes in pore space of the soils and the responses of the crop to the changed physical properties were measured. The sites used were: Barnfield at Rothamsted, a heavy clay loam long under arable cultivation and having little organic matter; Pastures Field at Rothamsted, a field of silty clay loam ploughed after an 8-year ley; Stackyard field at Woburn, a light sandy loam long in arable cultivation and containing little organic matter.

1. Swards of perennial ryegrass (S 24) were grown under conditions of high fertility and were cut at intervals of (a) 3 weeks, (b) 6 weeks, (c) 3 weeks changing to 6 weeks at later points in the growing season.

2. The rate of herbage production (kg D.m./ha/day) was higher throughout the season (April to November) under the longer cutting interval. Plots which were changed from 3- to 6-weekly cutting intervals subsequently showed the same rate of production as those cut every 6 weeks throughout.

Inflorescences emerged from a higher proportion of tillers after long growth periods; this could explain the higher rates of production up to July.

An experiment was conducted to compare the relative performance of fourteen populations of Italian ryegrass at sward and three non-sward densities. The non-sward densities were 3 in sown rows, 6 in square planting and 3 in square planting.Seven of the populations were commercial cultivars and seven were 50:50 mixtures of two cultivars.

1. The rate of clean wool production, carcass apparisal and reticulo-ruminal development of grazing sheep were used to evaluate differences in pasture quality. Perennial ryegrass, cocksfoot and tall fescue pastures were assessed as pure stands and also white clover.

The activity of alanine aminotransferase (Al. T) was determined in serum and liver biopsy samples collected from cows over a period of more than a year. There were statistically significant fluctuations in both liver and serum activities during the period of observation. On the whole serum and liver activities appeared to fluctuate independently of one another and of climatic changes. The only possible correlation was between the rate of increase in hours of daylight and the increases in serum and liver activities in the period January to March. The cows were calving at intervals throughout the year, and their liver and serum Al.T activities did not change significantly during the last three months of pregnancy and the first 3 months of lactation.

Between 1924 and 1934 Uganda, in common with many other African territories, tested arable rotations incorporating legumo green manures to maintain soil fertility (Martin, 1944; Uganda Dept., 1931–32) and it was concluded that the green manures failed to maintain fertility and were not worth the trouble involved. The Uganda Department of Agriculture accordingly changed its official rotations to modified forms of the indigenous shifting cultivation, namely 3 years of elephant grass rest alternating with 3 years of cropping. This same failure of green manures, combined with the apparent lack of correlation between crop yields and soil nutrient contents and the obvious deterioration of soil structure under crops, led Martin (1944) to the view that it was the physical not chemical condition of the soil which was important. Using his wet sieving technique he showed that, provided soils contained enough clay, all grass increased the water-stable crumbs over ½ mm diameter in the top soil and that 3 years under elephant grass was about optimal for restoring crumb structure.

1. A colony of honey-bees was put beside a 1/36 acre plot of male-sterile and male-fertile spring beans in 1965, but very little bean pollen was collected and no honey-bees were seen pollinating either male-fertile or male-sterile flowers.

1. In 1960 a 'reference plot' experiment was begun on Stackyard field at Woburn, where arable crops had grown for many years. The soil contained very little N or HCl-soluble K and little HC1-soluble P; it was acid, but was limed before and during the experiment to a pH at or near 7.0. Very small plots (0-00145 acre) were used.

1. Milk fat obtained from six Clun Forest ewes was analysed in the 1st, 4th, 8th and 12th weeks of lactation for fat constant values and fatty-acid composition.

1. The effects of changing the closeness of cutting at different times in the season on the yields and quality of herbage were studied for 3 years on a perennial ryegrass-white clover sward.

Sugar-beet plants require an appropriate sequence of environmental conditions to change from the vegetative to the reproductive phase during the first year of growth. When plants bolt, the stem lengthens and bears flowers and the stem and root become lignified. Bolting is normally induced by a period of low temperature followed by higher temperatures and long-day conditions. The minimum time necessary, under these conditions, for initiation of bolting varies greatly with individual plants, susceptibility to bolting being genetically controlled. Intensive selection for resistance to bolting has resulted in the production of varieties which are highly resistant to bolting (e.g. Bell & Bauer, 1942; Campbell, 1953; Campbell & Russell, 1964). Elongation of the stem can be induced, without normal vernalization, by spraying beet plants with the naturally occurring growth substance gibberellic acid (Gaskill, 1957; Campbell, 1958). It has also been reported that infection with virus yellows sometimes affects the incidence of bolting (Desprez, 1959), although it has not been recorded which of the two common yellowing viruses in Europe is responsible.

1. Twenty-one varieties of pasture grasses, including ten bred varieties, were grown on fertile soil for 3 years. Figures are presented of the rate of production of herbage cut every 3or4 weeks. Plots were cut in staggered sequence to permit growth intervals to overlap and to allow frequent assessments of the rate of production.