Experiments on permanent grass and newly sown Italian ryegrass compared ammonium hydroxide solution, with ammonium sulphate, ammonium nitrate, calcium nitrate and urea, applied at 56 and 112 lb. N/acre as solids, and also when dissolved in water to give a final N content of 5 %. Ammonium hydroxide solution containing 5% N damaged established grass severely and did not increase drymatter yields; when applied to the seed-bed before sowing Italian ryegrass, ammonium hydroxide solution did not affect germination but yields were lower than with other N fertilizers.

On permanent grass all fertilizers significantly increased dry-matter yields and N uptake at both cuts. The form of N fertilizer did not significantly affect dry-matter yields or N uptake of grass of the first cut. The method of application (i.e. solid or liquid) did not affect dry-matter yields, except that ammonium nitrate in solution gave a significantly higher yield than did the solid form at the second cut; the grass had higher N content with solid forms than with solutions. The grass took up more N from solid forms than from solutions except with ammonium nitrate at the second cut. Delaying the N application by 20 days decreased dry-matter yields considerably and increased the N content of the grass.

1. Symptoms of copper deficiency and toxicity were studied in guar, bottle gourd, eggplant and blue panic grass using sand culture technique.

2. The visual deficiency symptoms are: curling of the young leaves along the margins, chlorosis of the leaflets, necrotic spots on the leaves and drying of very young leaves in guar; loss of turgidity and drooping of lower leaves followed by chlorosis and drying of leaves in bottle gourd; faint green colour of the leaves, chlorosis of the outer rim of the older leaves, white necrotic spots and leaf scorch in eggplant; yellowish green colour of leaves, brownish white spots and depressed growth in blue panic grass.

3. The toxicity symptoms are: stunted growth, drying of the lower leaves and formation of few seedless pods in guar; chlorosis of the lower leaves and marked stunted growth in bottle gourd; dull green colour and chlorosis of the leaves in eggplant; stunted growth, leaf chlorosis and burning appearance of the plant in blue panic grass.

4. There is an increase in copper uptake with increase in the rates of application of copper.

5. There is a decrease in. the molybdenum content with increase in copper applications indicating the inverse copper-molybdenum relationship.

A tracer method has been used to determine the relative amounts of phosphorus that a range of short-term crops and fallows derive from different parts of their root zone when growing on a phosphorus deficient latosol. The short-term crops made little use of sub-soil phosphorus: millet derived 16% from below 12 in. after 95 days growth; and maize derived 7% and pigeon pea 11% from below 10 in. after 80 days. Pigeon pea feeds much closer to its base than the cereals until the 50th day. Since millet absorbed little phosphorus from subsoil placed in a layer only 5–10 in. deep, it is concluded that the poor uptake of subsoil phosphorus is due to low availability, rather than a natural surface feeding habit.

Pigeon pea in its second year extracted little more phosphorus from the subsoil than it did in the first. On the other hand, in a natural savanna both the perennial grasses and the associated dicots derived over 30% of their phosphorus from below the 10 in. layer. The amount corresponded with the proportion of dicotyledonous roots in the subsoil, but exceeded the corresponding proportion of grass roots. The greater proportion of subsoil phosphorus in the savanna may be due to lower availability of phosphorus in the topsoil, which in contrast to the other plots did not receive fertilizer.

1. The relationship between the level of feeding herringmeal and its effect on growth rate, feed efficiency and bacon quality has been examined in nine experiments, each consisting of three groups of seven (in one series six pigs). All experiments concerned herringmeal with about 7% petrol ether extracted fat, fed in combination with ground cereal grains and concentrates (Table 2).

2. Seven levels of feeding were tried. In the live weight period 20–30 kg they amounted to 3, 4, 5, 6, 8, 10 and 12%, herringmeal respectively. Later the percentages were successively reduced as follows: in the period 30–50 kg live weight 3/4, in the period 50–65 kg 1/2 and in the period 65–80 1/4 of the original amounts. No herringmeal was fed from 80 to 90 kg when the pigs were slaughtered (Table 1).

3. Increased levels of herringmeal produced increased growth rate and also brought about an increased feed efficiency. Most of the response was obtained with moderate levels, i.e. additions starting with 6–8%. Higher levels exerted more total effect, but these further accelerations progressively lessened. For initial additions of 6% herringmeal the growth rate improved on an average estimated at 8% and the feed efficiency by 5% compared with the performances of the pigs on an all-vegetable control diet, whereas corresponding figures for initial additions of 12% were about 13 and 7, respectively. Lower levels proved of little benefit (Tables 3 and 4 and Figs. 1 and 2). Growth-promoting effect of levels of 6% or more proved significant.

In the cows' intestine there is no isotony with the blood serum. In the upper part of the small intestine the chyme is strongly hypertonic but as it passes along the intestinal tract to the large intestine it becomes more and more hypotonic. The hypertony in the small intestine is not due to inorganic elements but is caused by organic non-electrolytes.

In the large intestine hypotony is the result of strong selective absorption of sodium against a concentration gradient.This is an important aspect of the sodium metabolism of the cow. Chlorine is also absorbed from the large intestine against a concentration gradient.

1. Queen-rearing and queen-introduction records of two honey farmers have been analysed.

2. Cells with newly grafted larvae were sometimes more readily accepted by queenless and broodless colonies than by queenless colonies with brood, or queenright colonies, and sometimes more readily accepted and built by queenless colonies with brood than by queenright colonies. Giving larval food with the larvae made little difference to acceptance.

3. Sealed cells and virgin queens wero more readily accepted by colonies dequeened for 3 days or more than by more recently dequeened colonies, particularly when the former had queen cells. Queen cells were the least successfully introduced to colonies which had been dequeened 3 hr. or less. Younger cells were better accepted than older cells in recently dequeened colonies, but not in colonies dequeened 3 days or more. Cell protectors did not increase the percentage of mated laying queens produced.

4. Mated laying queens were less successfully introduced to colonies with virgin queens, cells, or laying queens and cells, than to colonies with laying queens only.

5. In June and July cells and virgins were more successfully introduced, and mated laying queens less successfully introduced, than in other months. The acceptance of grafted cells did not vary with the time of the year.

6. The success obtained with cell building, and cell and queen introduction differed greatly in different years.

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.

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.

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.

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.

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.

Although considerable work has been done on basal metabolism and maintenance requirements of animals, maintenance needs in relation to total feed requirements for production have not received much attention in South Africa. Most workers have investigated production requirements, whilst the part of the total needs of the fattening of steers used for maintenance, has received very little attention.

This capital cost or ‘overhead’ expense is an item which constitutes a large proportion of the animals' fattening ration. In South Africa, only a small percentage of cattle is marketed under 4 or 5 years old. The maintenance cost of these animals must be considerable and the nett efficiency of beef production very low. As only the amount of a ration in excess of the maintenance requirements can be utilized for production, it follows that a level of nutrition well above the requirements for maintenance will facilitate a more efficient production system by narrowing the ratio between the part of the ration used for maintenance and that used for production. It is well known that differences in the efficiency of production between steers can only be due to the difference in the level of feed intake above maintenance needs—hence probably the strong correlation between rate of gain and efficiency of feed utilization. Apart from the actual determination of maintenance needs the object of this investigation was to determine the relationship between maintenance requirements and the total feed intake of beef steers when fed on fattening rations containing different ratios of concentrates to roughage.

1. An experiment was conducted to study the effects of progesterone and pregnant mare serum (p.m.s.) on incidence of oestrus, macroscopic changes in the ovaries, histological appearance of the genital tract, the vaginal smear and cervical mucus of New Zealand Romney Marsh ewes in deep anoestrus. Ten animals served as controls, thirty-five received progesterone daily for 4–12 days and ten were given p.m.s. alone. The remaining fifteen ewes were treated with progesterone for 4–6 days followed by p.m.s.

2. In ewes treated with progesterone alone, neither ovulation nor oestrus resulted. After p.m.s. alone six animals ovulated, while injection with both hormones caused ovulation in all 15 ewes and one was in oestrus.

3. Sections cut from the mid-region of the fallopian tube, uterine horn and cervix were examined. Histological responses to progesterone and p.m.s. were found in all positions of the tract and were greatest in the ewes which had ovulated.

4. In the ewes which ovulated a sequence of macroscopic and microscopic changes occurred in the vagina and these seemed similar to those associated with ovulation during the oestrous cycle.

5. Crystallization patterns in cervical mucus were seen in some ewes of all groups. Accompanying ovulation the phenomenon was seen for several days but was absent during most of the luteal period. When no follicles ruptured cervical mucus patterns often persisted. In most cases the presence and absence of arborization was presumably related to follicular oestrogen and progesterone from an induced corpus luteum and was in similar time relationship to that normally accompanying ovulation in the oestrous cycle. Some inconsistency in the response of cervical mucus following hormone treatment was noted.

6. No evidence was found that hormone treatment had initiated a regular cycle of ovarian activity.

The intake of dry matter from a pasture of Pangola grass by lactating dairy cows was measured. The chromic oxide administration technique was used. It was shown that the intake of dry matter was significantly higher in the dry season than in the wet. Reasons for this were discussed. An assessment of the nutrient intake of the animals was made and it was concluded that if the requirements of cattle in temperate climates was taken as a guide, this was adequate for at least maintenance and production of 1½ gal. per day of milk in the wet season. Under dry season conditions the intake of total digestible nutrients was adequate for the same level of production, but the digestible protein level was considerably below requirement. It was therefore concluded that supplementation with protein concentrates in the wet season was unnecessary save for high-yielding cows, but that all cows required concentrates during the dry season conditions of the experiment.

1. Individual herbage species were grown in pots and their magnesium contents studied throughout the growing season. The effects of treatments with sulphate of ammonia, superphosphate and calcined magnesite were also investigated.

2. Of the grasses studied timothy was consistently the lowest in magnesium content, the rye-grasses and cocksfoot being appreciably higher and similar. The clover species had higher magnesium contents than the grasses, especially in the spring.

3. The magnesium contents of the grass species were lowest in spring and showed a marked increase as the season advanced. The corresponding increases in clover magnesium content were considerably smaller.

4. The effects of sulphate of ammonia and superphosphate were slight increases in magnesium contents, but the calcined magnesite resulted in major increases in magnesium contents of both grasses and clovers.

Seedling beet plants grown on a fine soil separate produced more and larger leaves than those grown on coarser separates. This result has been ascribed to the greater quantity of available water, and the better root-soil water contact, in the fine separate compared with the others. Difficulties of root establishment in the coarser separates may retard the start of leaf development relative to that in the fine separates. Soil separates also affected leaf number, in some experiments, through their effect on seedling emergence, in that rapid emergence gave seedlings a slightly longer period for leaf production.

Fodder beet plants (variety Red Otofte) had a greater leaf number per plant at all counts than plants of any of the sugar-beet strains grown. Polyploid sugar-beet seedlings had larger leaves than diploid seedling.

Nitrogen applications to the seed-bed did not stimulate leaf production. In one instance, heavy fertilizerdressingsretardedleafproduction,probably by an osmotic effect.