Oats grown in a pot experiment on two sandy loams were sampled at four stages of growth. Neither KC1 nor MgSO4.7H2O had any effect on yield but % Mg and total Mg uptake were consistently decreased by applying K and increased by applying Mg.Ca(NO3)2 increased % Mg more than did (NH4)2SO4, but yield and total Mg uptake were higher where (NH4)2SO4 was applied. The effects of fertilizers were similar on both soils.

The effects of applying (NH4)2SO4 and NaNO3 to the soil on % Mg in barley were compared in a field experiment on an acid loam to which several rates of limestone had been applied. Treatments had no effect on the % Mg in grain or straw at maturity. At four earlier stages of growth (NH4)2SO4 increased % Mg in the plants more than did NaNO3. Limestone slightly increased % Mg. Nitrification of NH4 in the soil was rapid.

A study has been made of the effect of a progressive increase in the hours of light each day on the sexual activity of German Merino, Persian Blackhead and indigenous ‘Native’ ewes.

Incidence of oestrous tended to be greater in ewes subjected to extended daylight than in ewes subjected to the natural photoperiod. This was particularly true during the latter stages of the study. Duration of oestrus was unaffected by the extended daylight but varied temporarily in both groups of ewes. The effect of extended daylight on duration of the oestrous cycle and on the incidence of oestrous cycles of normal or abnormal duration was not marked and differed between breeds. Extension of daylight to 19 hr. each day apparently did not prevent reproduction since several light-treated ewes inadvertently conceived, gave birth to and reared a healthy lamb after a gestation period of normal length.

1. The object of the experiment was to determine the effects of varying the quantities of herbage available to cows on their diet and milk production.

2. Four groups of five Ayrshire cows were strip grazed for three periods of 3-4 weeks on areas calculated from sample cuts to supply (A) 25, (B) 35, (C) 45 or (D) 55 lb. dry matter per cow per day. These periods were interspersed between four standard periods of 2-3 weeks, in which all the cows were strip grazed on 50-60 lb. dry matter per head per day.

3. Measurements of milk production and of herbage consumption, by the chromic oxide-faecal nitrogen technique, were made for the last 12 or 16 days of experimental and last 8 days of standard periods. The observations made in the standard periods were used as covariates in the analyses of those made in the experimental periods.

Nine Cheviot and nine ¾ Merino, ¼ Cheviot sheep were fed at similar annual maintenance levels. The annual ration was provided in three ways–in simulation of the ‘natural’ intake cycle, the reversed intake cycle or as a constant daily ration. Liveweight curves for both breeds corresponded fairly closely with the feed intake curves but considerable genotype/environment interaction was found in the response of unscoured wool growth to variation in feed intake.

After an extended period of adjustment, the between sheep variation in intake, in the Merino group, was reflected in variation in wool-growth rate at all times. In the Cheviot group, intake and wool growth were related in summer but not in winter. It is suggested that not only is the efficiency of wool growth subject to genetic control but that the modification of efficiency in response to variation in environmentally controlled metabolic processes is also a function of the genetic background.

1. Sorghum is capable of giving substantial yields under dry conditions where maize fails.

2. Sorghum can consistently out-yield maize in some areas under conditions of apparently adequate or excessive rainfall.

3. Low soil nutrient status, and/or poor soil water relations, interacting with the amount of rainfall were probably responsible for the low maize yields where precipitation in the growing season exceeded 15 in.

4. Some hybrids originating in the U.S.A. may be of immediate value in dry areas of East Africa. Such hybrids are generally susceptible to bird damage and are more susceptible to Atherigona indica infuscate than local material. Hazera 726 shows less susceptibility to both these pests and is recommended for dry areas.

1. Experiments were carried out in 1961 and 1962 to study the effect of high levels of nitrogenous fertilizer on the health and performance of early weaned lambs. The lambs were artificially reared and grazed in a ‘worm-free’ area. In 1961, levels of Nitro-chalk were applied at 22 and 110 kg. N/hectare/month and in 1962 an intermediate level of 66 kg. N/hectare/month was added; the actual totals applied per hectare were 220,660 and 1100 kg. to treatments N1, N2 and N3 respectively. All nitrogen treatments were carried out with and without irrigation (applied to maintain a soil moisture deficit of less than 2.5 cm.).

2. Lambs were introduced to the experimental plots when 8-10 weeks of age and grazed in rotation a series of four paddocks on each treatment; a low grazing pressure was maintained at all times.

A co-ordinated trial has been carried out with fattening pigs at nineteen centres to compare the effects of the following methods of preparing and presenting the feed: (1) meal fed in the trough; (2) cubes fed in the trough; (3) meal fed off the floor; (4) cubes fed off the floor.

Pigs fed meal off the floor had substantially worse growth rate and feed conversion than pigs on any of the other three treatments, probably because of feed wastage. With trough feeding, pigs fed cubes had slightly better growth rate and feed conversion than pigs fed meal. When the feed was given as cubes, there was little to choose between trough feeding and feeding off the floor. Faster growing pigs were slightly fatter and had slightly smaller eye muscles.

1. On twelve occasions covering a complete seasonal cycle rumen mierobial end-product concentrations were measured in a group of sheep allowed to graze a pasture for 1 hr. Considerable differences were obtained in the rises in total volatile fatty acid and ammonia after feeding, in average rumen protein nitrogen and in free mierobial count.

2. Seven samples of fresh herbage wfere fed to groups of sheep in pens at different levels of intake. Increase in feed intake with five of the herbages produced significant increases in rumen ammonia and total volatile fatty acid and with one herbage there was a significant increase in protein nitrogen. Free mierobial count was measured after feeding three herbages and was found to be independent of intake level.

1. Five experiments, each with three steers, were made in which the same diet was given in three different amounts and energy and N metabolism measured. Fasting metabolism was also determined in each experiment. The experiments were made when the steers were 15, 31, 35, 46 and 81 weeks of age.

2. Age of animal had no effect on the apparent digestibility of the diet, methane production and urine energy loss from or on the metabolizable energy of the diet. The efficiency with which the metabolizable energy of the diet was used to maintain the animals and to promote energy retention by them was also unaffected by their age. The determined efficiencies were those to be expected from the results obtained in experiments with mature ruminants.

3. Retention of N was more efficient in the younger animals, and the composition of the gains showed that protein energy accounted for 30.5% of the total energy retained in the 15-week-old animals and 24.8 % in the animals 81 weeks of age.

1. This paper provides further information on the mineral content of the milk of Clun Forest ewes, particularly those elements not dealt with in a previous paper, namely, magnesium, sodium, potassium, and certain trace elements.

2. The average composition was as follows: calcium 0.200, magnesium 0.0147, sodium 0.046, potassium 0.168, phosphorus 0.140 and chlorine 0.076%; copper 0.22, iron 0.77, manganese 0.07 and aluminium 1.7 parts per million. Where possible the results are compared with those obtained by other workers for ewe's and cow's milk.

3. Statistical analysis of the data showed that, with the exception of phosphorus, the content of major elements varied significantly during the lactation period. There was also a significant variation in all major elements between sheep.

Data from one field and three glasshouse experiments are presented on the sodium and potassium contents of a number of grasses and on the effect of nitrogen, potassium, and sodium supply on these.

Large and consistent differences in sodium content exist between different genera of grasses. Potassium content may also show such differences.

Environmental factors which affect sodium content are the supply of nitrogen and potassium. Increasing nitrogen in the growth medium raises the sodium content, increasing potassium lowers it.

A grass with a potentially high sodium content will show a wide range in this element depending on the environment. One with a low sodium potential will remain always low, not unaffected by environment but affected within a more restricted range.

During the period 1959-62 liquid digested sludge was applied to grass to supply nitrogen at rates similar to those normally recommended to farmers. The responses were compared to those produced by equivalent inorganic fertilizers.

Liquid digested sludge gave as large an increase in dry matter as equivalent fertilizers. At the low rate of application the mean dry matter increase was 15.2 lb./lb. of applied nitrogen, and at the high rate the mean response was 11.0 lb. dry matter per lb. of nitrogen.

On one site, all treatments reduced the clover percentage, the high rate more than the low rate. Sludge treatments reduced the clover percentages less than equivalent inorganic fertilizers.

In a factorial trial comparing liquid digested sludge with equivalent water, and inorganic nitrogen, phosphorus, and potassium fertilizers, almost all the effects observed could be attributed to the uptake of nitrogen or potassium.

Over the 2-year period of treatment application, liquid digested sludge and equivalent inorganic fertilizer nitrogen and potassium gave similar responses of 22.3 and 23.8 lb. dry matter per lb. of nitrogen, and 59 lb./acre K increased the response to inorganic nitrogen alone by 5.4 lb./lb. of nitrogen.

Over the 2-year period of treatment the amount of potassium absorbed by herbage, in excess of that applied, was greater with fertilizer nitrogen than with liquid digested sludge. Added potassium had no direct effect on crude protein production. Liquid digested sludge and inorganic nitrogen fertilizer increased crude protein to a similar extent.

In a trial laid out to compare the effects of liquid digested sludge with equivalent nitrogen and phosphate fertilizers as ‘Nitra-shell’ and superphosphate, growth data, and data of grain and straw yield were obtained.

Liquid digested sludge increased the dry weight and shoot number at the ‘tillering’ stage, and dry weight and ear number at the flowering stage, more than equivalent fertilizer.

By 13 May, sludge-treated plants had absorbed more nitrogen than fertilizer-treated plants. By 19 June this was reversed for the sludge-treated plants had then absorbed 81% of the nitrogen absorbed by fertilizer-treated plants; ripe grain from sludge plots had a lower nitrogen percentage than grain from fertilizer plots.

1. The main objectives of the breeding programme were to develop two types of soyabeans:

(a) High yielding, non-shattering, resistant to lodging, determinate in habit, with pods formed 5-6 in. from ground level, for mechanical harvesting.

(b) High yielding, non-shattering but with no qualifications as to habit, for hand harvesting by African farmers.

An account of the breeding programme carried out on twelve crosses is given. The breeding method used was a combination of the bulk and pedigree methods.

1. An experiment was started in 1959 to measure effects on grazed permanent grass of ammonium sulphate, calcium nitrate, superphosphate and muriate of potash; yields and N, P and K contents of the herbage were measured from 1961 to 1964.

2. Applying 1.5 cwt. N/acre per year (in four bi-monthly doses) consistently increased yields. The first and fourth cuttings yielded less with 3.0 cwt. N/acre per year (also in four bi-monthly doses) than with 1.5 cwt. N/acre, but the second and third cuttings yielded more; the total additional yield from 3.0 cwt. N was small. Yields were increased equally by ammonium sulphate (providing that lime was also applied) and calcium nitrate.

3. Yields were increased more by P than by K; the increase from P was greater when N was also applied.

1. Some of the effects of stress, fasting and ACTH injections in pregnant ewes were investigated.

2. A 6-day fast produced a relatively mild hypoglycaemia and hyperketonaemia without inducing pregnancy toxaemia.

3. Stress of transport produced an immediate slight rise in plasma cortisol; 4 hr. later the plasma cortisol had returned to the pre-stress levels.

4. A combination of stress and fasting produced severe hypoglycaemia, hyperketonaemia and subacute pregnancy toxaemia, but there was no increase in plasma cortisol levels.

5. Daily injections of ACTH resulted in a fourfold increase in plasma cortisol and prevented the development of hypoglycaemia, severe hyperketonaemia, and pregnancy toxaemia in pregnant ewes subjected to stress and fasting.

6. Changes in plasma concentrations of NEFA, urea, proteins, catecholamines and insulin were also investigated.

In an experiment in which plots of S24 perennial rye-grass grown at a 2 in. spacing were subjected to pretreatments involving two different nitrogen levels and three different cutting frequencies it was found that subsequent regrowth was most strongly related to total stubble weight. Other significant correlations were obtained with root weight, tiller number and weight of water-soluble carbohydrates in roots and stubble.

The relationships between cultural treatments and sward condition, and between sward condition and regrowth are discussed in the light of the results from this and other experiments.