During the winter of 1956, an experiment was conducted, using seventy beef steers of three different age-groups to determine intake and digestibility, by means of the indicator method, of mixed rations differing in ration concentration.

In the first part of the experiment, six pairs of steers of three age-groups receiving two types of rations were used. The pairs were selected on the basis of their rate of gain and constituted the fastest and slowest gaining steers of their respective age and ration groups. The object of the experiment was to ascertain whether any correlation could be found between the rate of gain of the steers and the degree to which the ration was digested.

Two indicators were used, namely, the internal indicator lignin and Cr2O3, administered twice daily by means of gelatin capsules, containing 7·5 g. of the indicator.

Using lignin as an indicator of digestibility, it was found that the calculated digestibility coefficient of both rations varied. A larger variation occurred, however, in the case of the ration with a concentrate to roughage ratio of 2:1 than in the case of the ration with a ratio of 1:3·6.

1. The amounts of wood shavings eaten by a group of unmuzzled calves allowed unlimited access to the shavings but fed otherwise only on milk were estimated by a lignin ratio technique. The amounts increased to a mean value of about 250 g. dry weight/day at 13–14 weeks of age.

2. Although a marked decrease in net magnesium absorption from the diet occurred with age in a group of efficiently muzzled milk-fed calves the mean decrease was not as great as that in the group of unmuzzled calves when the latter were eating considerable amounts of wood shavings. Data are presented which show that the difference is accountable by the excretion in the faeces of some of the magnesium in the increased flow of endogenous fluid from the rumen (probably mainly saliva) in the unmuzzled calves. The results suggest that many milk-fed calves (assuming about 11–12 mg./100 ml. magnesium in the milk) will resist hypomagnesaemia for at least 5 months but only if they are effectively prevented from chewing foreign matter. This may partly account for previously observed variations in. the ages at which calves develop hypomagnesaemia.

3. Net calcium absorption from the diet decreased with age in both the muzzled and unmuzzled groups of calves but again to a greater extent in the unmuzzled group. The difference was much greater than could be accounted for by increased loss of endogenous calcium due to greater saliva production in the unmuzzled calves. It appeared that the shavings contained a factor (not phytate) which interfered with calcium utilization. It is suggested that the factor might act by inhibiting the action of vitamin D.

The daily intake of dry matter by zebu steers between 400 and 600 lb. live weight when fed hay and hay-concentrate mixture was investigated and found to be 2·0–2·2% of body weight.

Preliminary results of the nutritional values of Rhodes grass and Star grass hays are discussed and these suggest that the local zebu cattle require less starch equivalent for maintenance than do European cattle in temperate climates.

1. Evidence is presented to show that compared with an unmulched soil, a surface mulch reduces the nitrate-N levels significantly following an application of a nitrogen fertilizer during the rains.

2. Natural nitrate-X values in the top-soil were lower under a gravel mulch than a Napier grass mulch. It is concluded that the effect of a Napier grass-mulch cover in lowering natural soil nitrogen-N is offset in part by nitrates formed from the nitrogen it contains.

1. Results are presented which refer to the behaviour of twenty young East African shorthorned zebu heifers grazing a Chloris gayana ley at Serere Experiment Station in north-east Uganda. The heifers were studied for two trial periods, each of 72 hr. duration, one during the transitional season and one during the dry season.

2. Five of the heifers were recorded individually, and the results showed a fair degree of variation in behaviour between heifers. The difference in total ruminating time between two heifers was statistically significant, but all other differences were nonsignificant.

3. The day to day variation in behaviour was very small. There was no significant difference in the time spent engaged in any major activity between the 3 days of either trial.

4. During the transitional period of the year between the wet and dry seasons, young heifers spent 8·6 hr. grazing (22·5% at night; 77·5% by day) and 7·0 hr. ruminating out of a 24 hr. period. During the dry season, the heifers spent 7·8 hr. grazing (25·2% at night; 74·8% by day) and 6·5 hr. ruminating. There were no other important differences in behaviour time between the two seasons.

5. In the transitional season the grazing was divided into three distinct periods, two during the day and one at night. In the dry season the afternoon grazing period was divided by a short resting period into two parts, making four periods in every 24 hr. An average of 2 hr. were spent night-grazing in both seasons, and this night grazing was independent of moonlight.

The work reported in two previous papers, Robinson (1960a, b) led to certain conclusions which required evaluation in terms of coffee yields (Coffee arabica Linn). The work describes changes in nitrate and ammonia-N in the Kikuyu red loam coffee topsoil, both natural and fertilizer derived, in the presence and absence of mulches.

This paper presents early coffee yield results which have been obtained from field trials laid down on the Coffee Research Station, Ruiru, Kenya, to measure the effect of treatments based on the conclusions drawn from the soil studies.

Peat soils change gradually as a result of drainage and cultivation, losing depth through shrinkage, oxidation and blowing, changing in character through increases in mineral matter and ‘drumminess’, and changing in productivity and manurial requirements. The sequence of changes has been studied in the field and a number of stages distinguished which may be recognized quite simply from the texture of the ploughed layer. Texture is a field assessment of the type and condition of the peat and the proportion and nature of the mineral matter associated with it. The Fenland soils have been classified as follows: (1) peat soils, (2) peaty mineral soils, (3) organic mineral soils and (4) mineral soils. Further subdivision into textural classes depends on recognizing the mineral combinations or fractions as in texturing mineral soils

Analysis of samples of the ploughed layer in the laboratory has shown that organic matter or loss on ignition figures, expressed as a percentage of the oven-dried soil, can be used for recognizing the kind of soil; use is made of this in considering those earlier experiments for which organic matter figures could be calculated.

A fine soil separate gave the highest and most rapid seedling emergence. This was considered to be due to its better moisture supply characteristics and the lower mechanical impedance compared with coarser seed-beds. There was no evidence that natural seed clusters are any less responsive to soil aggregate size than processed beet seed clusters.

Consolidation slightly hastened emergence, though the mechanism of this is not clear. Sowing at ¾ in. was superior to deeper sowing (1½ in.), both in speed of emergence and in ultimate emergence. This was partly an effect of decreased mechanical impedance, and partly due to the shorter period over which the seedlings were susceptible to pathogens. Heavy dressings of soluble fertilizers were found to delay emergence, though without effect on the ultimate emergence.

1. Pellets of L-thyroxine (30 mg.) were implanted subcutaneously in sheep. The loss in weight of the implants and the plasma P.b.i. level were determined at intervals.

2. The P.b.i. concentration increased within a few days from a normal value of around 5 μg./100 ml. to one of 15–20 μg./100 ml. After 10–20 days the concentration slowly returned to normal, and at 70 days subsequent to implantation was only slightly above the normal level.

1. Seasonal changes in wool production per unit area of unstretched skin, number of fibres of each type per unit area, ratio of fibre types, mean fibre weights, lengths and diameters and degree of medullation are given. The production cycle shows a peak in August and September and a trough in February and March, the weight of wool produced in the latter period being only 16% of that in the former. Approximately 80% of the fleece is produced in the 6 months from June to November (lambing ewes). Other components show similar trends.

2. The production cycle does not entirely coincide with the nutritional cycle as estimated from bodyweight changes before late pregnancy. Whilst bodyweight increases from September to November wool production declines by about 25%.

3. The winter drop in wool production per unit area is caused partly by a decrease in the mean weight of each fibre type (in turn made up of a decrease in both length and diameter) and partly by a 50% reduction in the number of active fine fibre follicles and a 100% reduction in active kemp follicles. There is no apparent change in the number of active coarse fibre follicles. The degree of medullation of both coarse and fine fibres declines substantially between December and May.

1. A preliminary trial involving forty-six ewes demonstrated that when ewes in store condition were flushed for different periods, there was a marked increase in ovulation rate after 1 month with no further increase after 2 or 3 months. Flushing did not lead to ovulation rates higher than in ewes maintained in fat condition.

2. When similar ewes in fat condition were fed submaintenance diets there was no decline in ovulation rate while the animals had good body reserves, but as the period of submaintenance feeding was extended there was a gradual fall in ovulation rate.

3. In the main experiment forty-eight ewes were allocated to four groups of twelve ewes each. One group was fed a submaintenance diet till they were in moderately poor condition (submaintenance group). The other three groups were reduced to store condition and were then flushed on good pasture for 5–8 days, one oestrous cycle and two oestrous cycles, respectively. All ewes were slaughtered 2–5 days post-oestrus and half the ewes of each group were injected subcutaneously with 600 i.u. of P.m.s. on the twelfth or thirteenth day of the oestrous cycle prior to slaughter.

1. The availability of iron in three herb species has been investigated, using the rat as the experimental animal.

2. Two procedures were employed, namely, the increase in blood haemoglobin concentration, and the gain in total grama of haemoglobin, by nutritionally anaemic rats.

3. Inorganic iron, as ferric chloride, was shown to be significantly more available than the iron contained in the three herbs.

The variations in fleece components over the body of the Blackface sheep are described. The differences amongst regions are relatively large and highly significant. The structural components—density, fibre type ratio and weight per unit area—are more variable than the fibre characteristics—weight, length and diameter. Fairly regular patterns are found which approximately correspond to those found in other breeds and there is evidence of significant animal by site interaction. It is concluded that neither fixed nor random site sampling can be regarded as ideal but that the best procedure would be single or multiple sampling in the mid-side region.

Corriedale ewes in New Zealand on a constant ration throughout the year were subjected to various light treatments and their monthly growth of wool compared with controls having normal daylight hours.

1. In the controls the peak of wool growth occurred during November–January with long daylight hours and the minimum during June–August with short daylight hours.

1. The energy metabolism and heat emission of two steers was determined at the maintenance level of nutrition in an environment of – 5, 5, 15, 25 and 35° C. and at a submaintenance level of nutrition in environments of – 5 and 19° C.

2. Shivering was observed at temperatures of – 5 and + 5° C. in both animals. Respiratory distress occurred at 35° C. being more severe in one animal than in the other. The animals stood for longer periods at the extreme temperatures.

3. The digestibility of food increased slightly as environmental temperature increased. Losses of energy as methane and in urine did not change in response to environmental temperature.

1. The water and food intakes of sixteen grade Shorthorn and Boran zebu steers have been studied.

2. A difference has been shown in the water requirements of Shorthorn and Boran cattle.

3. Modest supplementation with salt, of animals on an otherwise sodium deficient diet, had no significant effect on either water or food consumption.

4. Differences in environmental temperatures are suggested to explain the higher intake of water in one of the experimental periods. The increased water intake for the Borans was less than half that for the Shorthorns, only the increase for the latter being significant.

Plants from salt and potash fertilizer trials at Bothamsted were harvested at intervals throughout the growing seasons of 1942 and 1943 and analysed for N, K, Na, Ca, Mg and Mn.

The uptake of nutrients is discussed with respect to field methods of fertilizer application.

Salt increased beet yield in both years, but it did not act by mobilizing soil potassium reserves and increasing the potassium status of the plant. Potash fertilizer, although increasing the potassium status of the plant, did not increase yield. Sodium and potassium were differently distributed in the plant. At harvest, only 6% of the plant's sodium content was in the root compared with 33% of the potassium. The potassium, but not the sodium content of the petiole, was higher than that of the lamina until the end of August. Sodium thus is a nutrient for beet and not a potassium substitute.

The theory of conducting trials of apparent digestibility is simple but the practical side is expensive and requires well-trained staff. In Uganda there is a very pronounced shortage of skilled technical staff and, because of this, equipment used must be as simple as possible to avoid errors of handling and analysis of herbage and faeces. The series of investigations carried out by the authors was planned to simplify the techniques and equipment used without decreasing accuracy to any significant extent. This paper deals with the simplified apparatus which was finally used.

1. The effects of restricting the daily grazing hours of indigenous cattle have been studied on grazing behaviour and cattle weights. The cattle grazed on natural veld.

2. Three cattle-management treatments, i.e. free range, moderate kraaling (11 hr. grazing day) and severe kraaling (7 hr. grazing day), were compared during seasonal periods of low cattle-weight gains, large cattle-weight gains and large cattle-weight losses.

Some techniques of sampling, preserving, drying and for determination of nitrogen content of faeces were investigated.

It was found that any sample between 100 and 600 g., made up of 10 g. subsamples taken at random, is satisfactory.

Untreated faeces and those preserved by the addition of acetic acid, hydrochloric acid or toluene were dried in a large oven at 80° C. and compared with untreated samples dried at 105° C. for 8 hr. Duplicate samples of those dried at 80° C. were exposed to room temperature for 7 hr. and then dried. When dry-matter and crude-protein contents were compared no significant differences were found between the three groups.