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.

Article by D. F. Osbourn and P. N. Wilson:

‘Effects of different patterns of allocation of a restricted quantity of food upon the growth and development of cockerels.’

Wherever Figure 1 is referred to in the text, Figure 2 is meant.

The caption to Figure 1 should be placed under Figure 2 which has no caption at all. The caption of Figure 1 should read ‘Curves showing the liveweight gains of cockerels on the three treatments, (g.)’

The ordinate on Figure 2 should read ‘daily food consumption (g.)’

1. A study has been made of some of the factors influencing the role of clover in grass-clover swards fertilized with nitrogen at different rates.

2. From 1955 to 1957 inclusive three nitrogen treatments, 0, 4 and 10 cwt. ‘Nitro-Chalk’ (15·5% N)/acre/season, were applied to twentyone grass-clover mixtures sown in the spring of 1954. The mixtures contained either S 184, S100 or Kersey white clover alone or in association with one of the following grasses, S 23 or S 24 perennial ryegrass, S143 or S37 cocksfoot, S48 timothy or S53 meadow fescue.

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 statistical analysis was undertaken to study persistency of lactation in buffaloes, using the milk records collected on a herd of buffaloes belonging to the Ministry of Agriculture at Sakha Experiment Station. The number of buffaloes included in this report was 328 animals having 722 lactations. A formula was developed for estimating persistency of lactation in buffaloes and results obtained are as follows.

1. A brief description is given of an experiment in which some of the factors influencing the role of clover in grass—clover swards fertilized with nitrogen at different rates were studied.

2. Reference is made to a previous paper detailing the experimental methods and reporting the results pertaining to the effects of the grass varieties included in the seeds mixture on the yields of mixed herbage and of clover. The effects of the clover varieties on these yields are discussed in the present paper.

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. Ten experiments are reported in which the effect of high-level copper supplementation of pig rations on growth rate and food conversion was observed. In three of the experiments the study included observations on carcass quality.

2. In nine of the ten experiments a positive increase in the growth rate of the pigs receiving copper was recorded but the magnitude of this increase was markedly variable.

The aim of this investigation was to study the repeatability and heritability of initial milk yield and persistency of lactation in buffaloes. The interrelationships between 305 days milk yield, initial milk yield and persistency were also investigated.

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.

A description is given of a double change-over, grazing trial designed to test the value of Hyparrhenia veld grazing for milk production during the rains.

Three feeds were offered to lactating cows, and the effects of qualitative differences between the feeds were measured on milk yields. The treatments were:

Semen characteristics and libido were observed for 34 months in German Merino, Persian Blackhead and indigenous ‘Native’ rams maintained on Rhodesian highveld. Birth rate from controlled service was determined during 23 of these months.

1. Breeding ability, as judged by semen production and libido, was continuous in all rams. A fluctuation in birth rate from controlled service was due more likely to seasonal variation in female fertility than in seminal fertilizing capacity.

2. Monthly changes occurred in all seminal characteristics but only those in sperm concentration were consistent between years. In all breeds spermatogenic activity was high in spring and mid-summer, low in late summer and autumn.

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.

The paper reports the results for six factorial experiments carried out over a period of 3 years, and designed to measure the effects of nitrogen, phosphate and potash on the yield of dry matter and to determine the effect of nitrogen on the phosphate and potash requirements of grass being cut five times per annum for conservation.

Heavy dressings of nitrogen reduced the percentage of dry matter in the fresh herbage, but produced a very large increase in the yield of dry matter. There were quite large variations in the response to this plant food, but 348 lb. N per acre per annum practically doubled the yield and generally the response curves were substantially linear.

The response to nitrogen depended on an adequate supply of potash and at five of the centres there were very large interactions between these two nutrients. The need for potash was greatest at the highest nitrogen rate and was much greater in the second and third than in the first year of the experiments.

At the highest nitrogen rate some of the responses to potash were very large. The yields of dry matter showed no large or consistent differences between applying 336 lb. K2O in one dressing during the winter months or applying this amount in five equal dressings, one for each cut. The results demonstrated the ability of the soils to supply potash and showed that the regular cutting and removal of herbage, especially if heavy dressings of nitrogen were applied, exhausted the potash reserves in the soil.

Phosphate had practically no effect on the yield of dry matter either in the presence or absence of nitrogen.

With adequate potash the production of dry matter per lb. of fertilizer nitrogen was practically independent of rate and the overall mean results are between 14·0 and 15·7 lb. In the absence of fertilizer potash there was a very large effect of rate: 15·0 lb. dry matter per acre was produced per lb. N with the 87 lb. N per annum treatment, 13·7 lb. with 174 lb. N and 10·0 lb. with the 348 lb. N treatment.

Approximately 70–75% of the annual production was obtained before the end of July. Thus 1 lb. of fertilizer nitrogen produced considerably more dry matter per acre during May, June and July than later in the season.

German Merino, Persian Blackhead and indigenous Native rams were exposed to gradually increasing day-length simulated by use of electric light in the night pen. Between February and June experimental day-length increased from 14 hr. 35 min. to 17 hr. whereas natural day-length fell from 13 hr. 50 min. to 12 hr. An additional trial was superimposed on the main experiment to determine the effect of vitamin A injections on reproductive function and on ability to respond to photoperiodic stimuli.

The effect of age on attainment of puberty and on seminal characteristics in yearling and mature rams was studied in German Merino, Persian Blackhead and indigenous Native rams living on Rhodesian highveld.

1. Puberty occurred at age and live weight proportional to mature live weight. Well-grown Native lambs ejaculated first at 169 days of age and 46 lb. live weight; Merino lambs when 250 days old and 79 lb. live weight and Persians were intermediate. Onset of sexual maturity was related more closely to live weight than to age, since runts ejaculated first at live weights close to those of well-grown lambs.

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.

Evidence of natural selection for certain aspects of mating efficiency in swine are advanced based on preliminary studies with thirty-one sires, fiftyeight dams and their progeny. Selective fertilization was conclusively demonstrated. Variations in male and female mating behaviour were sufficiently large to indicate considerable non-randomness of mating frequency under the conditions of multiple sire mating (i.e. group exposure of dams to selected sires). The combined effects of the separate phenomena of selective fertilization and mating behaviour are discussed in relation to their evolutionary significance in animal breeding.

1. Fifteen experiments on spring barley (mainly Proctor), done from 1957 to 1959, compared alternative alternative methods of applying 0·3, 0·6 and 0·9 cwt. N/acre.

2. Combine-drilling 0·3 or 0·6 cwt. N/acre as ammonium sulphate produced higher mean yields than broadcasting, but drilling 0·9 cwt. N/acre checked early growth and reduced mean yields in two of the three seasons.

The effect of various diluents and different dilution rates on the maintenance of motility of ram sperm during storage at 4° C. was tested. Their efficiency was determined by half-life periods and total survival times of the sperm.

A yolk-glycine-citrate diluent maintained sperm motility for a longer period than did yolk—fructose—phosphate, yolk-citrate, cow's milk and ewe's milk, with or without yolk. This diluent has the advantage that the sperm is clearly visible under the microscope, and no sedimentation of any component occurs.

A modified IVT diluent prolonged the total life span of the sperm, but caused a faster motility decline in the first part of the storage period.