A general account is given of four experiments in which the action on the soil of the Fowler “Gyrotiller” has been compared with that of the traditional cultivation implements. The gyrotiller has produced well-marked changes in the soil on both heavy and light land. These changes have been demonstrated and recorded by tests of the compactness, the resistance, the degree of comminution and the permeability of the soil.

On the heavy land, the initial effect has been to produce a very loose and open soil. This has gradually settled down until, after the end of the first winter, no difference in compactness was demonstrable by means of the revolver test. But the resistance of the soil, measured by a special recorder and by plough drawbar tests, has remained demonstrably lower on the gyrotilled plots than on the controls for a considerable time after this, and a method of soil fixation has shown that small cavities persisted for more than a year. In one experiment, differences in resistance have been shown to exist up to 19 months after gyrotilling.

In a hybridization programme to study the genetics of resistance to bacterial blight of cotton within Gossypium herbaceum, a major gene, thought to be homologous with Knight's B9, was found in Wagad 8. The strain Chinese Indigenous was also found to possess a major gene for blight resistance but this gene was non-homologous with B9In addition genes there were strains of cotton. to the aforementioned major genes of small effect in both

Methods for extraction, concentration and determination of minute quantities of soluble carbohydrates, lactic acid and volatile fatty acids have been described. Different factors affecting the accuracy of the determinations have been studied and corrections, where necessary, have been suggested.

An account is given of a preliminary experiment on artificial insemination of cross-bred Merino sheep in Kenya. 202 ewes were inseminated and 74·3 per cent conceived. The practical application of artificial insemination to sheep breeding in Kenya is discussed.

In the present study, precise, animal-based biometric data on the space needed for the body dimensions of individual pigs (static space) were collected. Per batch, two groups of eight piglets each were formed after weaning (35 days old). Using three-dimensional cameras that recorded a piglets’ pen from above and newly developed software, the static space of individuals was determined over 6 weeks. The area covered by an individual increased almost linearly with increasing body weight (R2 = 0.97). At the end of rearing (25 kg body weight), an individual covered 1704 cm2 in standing position, 1687 cm2 in sitting posture and 1798 cm2 in a recumbent position. According to the allometric equation: Space = k × body weight0.667, k values for the static space in standing position (k = 0.021), in recumbent position in general (k = 0.022) and in lateral recumbent posture (k = 0.027) were calculated. Compared with spatial requirements in different countries, the results of static space obtained in the present study revealed that pigs weighing 25 kg are provided with 0.09–0.18 m2 free space per pig which is not covered by the pig's body. This free space can be used as dynamic space needed for body movements or social interactions. The present study was not intended to enhance space recommendations in pig farming, but to demonstrate the amount of free space in a pigs’ pen. It was shown that innovative technologies based on image analysis offer completely new possibilities to assess spatial requirements for pigs.

From a study of the data of two season's work the following observations may be made:

Frequency of grazing with a view to the successful operation of the scheme will depend on a number of factors, chief among which is the character of the herbage and its growth. Recovery and vigour of growth are primarily dependent on rainfall and secondarily on the fertility of the soil, which may be increased by fertiliser applications. Rainfall, its amount and distribution, has in this investigation shown itself the most potent of all influences in the recovery of the plots. The results in general of 1928 indicate that the application of fertilisers, in which nitrogen predominates, greatly assisted in the maintenance of vigorous growth.

The protein content of the herbage increases with the shortening of the period between cuttings, due in the first season solely to the fact that the protein content of the grass falls off with age, but in the second and subsequent seasons, in a very large measure, to the incursion of white Dutch clover.

A consideration of protein yields per acre in relation to frequency of cutting reveals that in the first season, when the herbage is essentially grass, the shortening of the period between cuttings tends to reduce the protein yield; in the second season, when clover replaces grass, roughly in proportion to the shortening of the growing period, the higher protein content of the legume tends to counteract the depressing effect on yield of frequent cutting.

Italian rye-grass was grown in the greenhouse in clay loam soil in winter 1962 with several rates of a nutrient solution containing NO3-N and P, K, Ca and Mg to see whether the grass had maximum values for sums of the cations and anions (σ cations, σ anions). Two other experiments were done in summer 1962 with a similar nutrient solution containing either NO3-N alone or NO3-N plus NH4-N.

At the same level of added nutrients summer yields of grass were about twice those in winter and there was little difference when nutrient mixtures with NO3-N+NH4-N or with NO3-N alone were used. The sum of the cations (m-equiv./lOO g. dry matter) in the grass was positively correlated

The organism which produces “Blackleg” of the potato in Lancashire is B. atrosepticus (van Hall).

It is in all respects identical with the organism responsible for this disease in Ireland and described by Pethybridge and Murphy under the name B. melanogenes.

More than 200 wild type isolates of chickpea (C. arietinum) rhizobia were screened for their drug resistance. Only 15 were found to be resistant to one or more antibiotics at a concentration of 5 μg/ml (units/ml). When tested for multiple drug resistance, some were found to be resistant to more than one antibiotic. In competition studies, rhizobia resistant to streptomycin were found to be more competitive than antibioticsensitive strains, while those resistant to penicillin could not compete even with antibiotic-sensitive strains.

Different management regimes for 1-year rotational set-aside were tested in three experiments that followed winter wheat and started in autumn 1988–90. The regimes included operations that prevented the establishment of volunteers or allowed them to establish and persist until either spring or summer, and also altered the distribution of debris from the winter wheat that preceded the set-aside. For comparison, treatments in the set-aside year also included winter wheat.

Samples taken in spring from the first test crop showed that there were few significant or consistent effects on leaf diseases of growing the wheat after different set-aside treatments or after winter wheat. There were significant effects of the set-aside treatments on root and stem base diseases but some of the effects, and the apparent absence of others, are not easily reconciled with current understanding of the biology of the pathogens concerned. In summer, eyespot (Pseudocercosporella herpotrichoides) was most severe after winter wheat and least severe after ryegrass. Severity after the other set-aside treatments did not differ significantly. There was more sharp eyespot (Rhizoctonia cerealis) in plots that had been ploughed at the start of the set-aside year, including those sown with winter wheat, than in those that had not. Brown foot rot (Fusarium spp.) was equally severe where the wheat followed wheat or where it followed set-aside treatments that allowed volunteers to develop, and less so where the development of volunteers was prevented. Take-all (Gaeumannomyces graminis var. tritici) was most severe after winter wheat and more severe after set-aside treatments that allowed volunteers to develop and survive through the winter than after those that did not. Effects of ryegrass (Lolium perenne ssp. multiflorum) on take-all in the following wheat were particularly variable, perhaps because ryegrass is a host of both the take-all fungus and of Phialophora graminicola, one of its principal antagonists.

1. Healthy tubers and “primarily infected” tubers, at time of lifting, appear to be similar both in external appearance and chemical composition.

2. On drying at laboratory temperature (about 60° F.) healthy tubers lose weight much more quickly than “primarily infected” tubers. In addition, the latter remain in a “hard” condition which persists even after sprouting whereas the former become soft and flabby.

3. It is suggested that healthy “seed” may be separated from “primarily infected” seed on this basis.

The work described in this paper deals exclusively with the yeast flora of certain bottled ciders. It was undertaken as a section of an extensive scheme of investigation of the organisms which are concerned in the fermentation of English-made ciders. Apart from the more purely biological side of the question the main objects of the whole scheme are to determine how far the customary method of conducting the fermentation of cider in this country is satisfactory, and whether it could be improved, from a practical point of view, by certain modifications or by the substitution of other processes, such, for example, as the use of selected yeasts.

Calcium metabolism in dairy sheep was studied using radioisotope and balance techniques. The rate of calcium absorption increased, but the efficiency of calcium absorption decreased, with increasing calcium intake in dry sheep. Endogenous faecal and urinary calcium losses, and the rate of calcium absorption, decreased, but the efficiency of calcium absorption increased in pregnant sheep given a calcium-deficient diet. The rate and the efficiency of calcium absorption and the calcium balance of lactating ewes were not influenced by the prepartum level of calcium intake, when calcium intake in early lactation was high. Endogenous faecal calcium loss was related to dry-matter intake, and total faecal calcium loss was related to calcium intake.

1. A feeding trial was carried out using fortyeight Large White pigs, individually fed in a Danish type piggery. Six different diets prepared at two levels of digestible energy and three levels of crude protein were fed to eight replicates consisting of four hogs and four gilts per replicate. A record was maintained of the weekly live-weight gain and food was given at a defined restricted level in relation to the live weight. Carcass quality was assessed by complete dissection into visible lean, fat and bone etc.

2. Of the main effects, energy, supply was without significant effect upon growth, food conversion efficiency (FCE) or any carcass characteristics except body length which was increased with a high energy level. The protein level in the diet had a significant effect upon the percentage of carcass lean and the killing-out percentage, the higher levels of protein increasing both these measurements significantly. Gilts were significantly superior to hogs in every carcass measurement although hogs grew significantly faster.

An unknown phosphorus fraction previously recorded by the authors as frequently present in calf blood, is shown to be nucleoprotein and due to the presence of precursors of fully mature erythrocytes. The same fraction may also appear in small amounts in human blood and in horse blood, and always occurs in very large amount in the nucleated erythrocytes of birds.

Topping of tobacco (Nicotiana tabacum L.) plants (removal of the inflorescence) is not practised in Cyprus. Two field experiments were carried out at Akhelia Station, in 1985 and 1986, to test whether topping increased the yield or improved leaf quality of flue-cured tobacco grown under different types of irrigation. In contrast to the results of other studies, topping when the corolla had appeared on half the flowers did not increase yield. Topping when the inflorescence was just clear of the leaves (21 leaves harvested from topped plants v. 32 leaves from untopped plants) increased fresh yield by 7·0% but dry matter yield by 18·0%. The effects of topping were more marked on the leaves reaped at the third and fourth harvests, which constituted 52% of the fresh yield or 60% of the dry matter yield. At these harvests, leaves from topped plants had a lower percentage of midrib material (18·5 v. 21·0%) than leaves from untopped plants but a higher dry matter content (19·2 v. 17·2%) and specific leaf weight (80·0 v. 56·0 g/m2). Leaves of the fourth harvest from topped plants (27% of the total fresh yield) contained appreciably more nicotine (1·34%) than leaves from untopped plants (0·40%) but had a similar content of reducing sugars (20%). Topping did not influence the N, P and K contents of the leaves.

Irrigation increased fresh yield from 12·0 t/ha (225 mm water) to 24·0 t/ha (450 mm water) and dry matter yield from 2·0 to 3·8 t/ha, respectively, in Expt 1.

As Cypriot tobacco growers are paid for fresh yield delivered to the curing plant, the marginal increase of fresh yield with topping will hardly cover the cost of the extra operations involved.

Normal and ketotio ewes pregnant with twin lambs were injected intramuscularly with 0·5 mg/kg body weight of trienbolone acetate. In the normal animals there was no significant change in the concentration of glucose, ketones, glycerol or NEFA in plasma.

Induction of ketosis by starvation produced a significant fall in the concentration of glucose in plasma and significant increases in the concentration of ketones, glycerol and NEFA. Trienbolone caused no further significant changes in the concentration of the four metabolites in the plasma of ketotio sheep.

Primed continuous simultaneous intravenous infusions of tracer amounts of [2-3H] and [U-14C]glucose were used to measure total entry rate and irreversible loss of glucose. Trienbolone caused significant decreases in both these measurements in normal pregnant sheep. Production of ketosis by starvation had the same effect. Trienbolone produced no significant additional effect in the ketotic sheep and no alleviation of the clinical signs of the hyperglycaemic ketosis.

These results are discussed in relation to the assessment of the potential value of trienbolone as a treatment of pregnancy toxaemia of sheep.

Granular calcined magnesites originating from Spain, China and Greece and magnesium hydroxide powder were evaluated in a series of balance experiments conducted with wether sheep (c. 42 kg liveweight) given a basal ration of dried grass at Glasgow University Veterinary School between 1989 and 1994. Four Spanish ‘Agma’ products and three Spanish ‘Navarras’ products contained less material (0–104 g/kg)>1000 μm diameter than four Chinese and four Greek materials 178–483 g/kg). The Spanish products had lower (18–45 g/kg) losses on ignition compared with the Chinese and Greek materials (53–112 g/kg). A fifth Greek product contained only 4 g/kg>1000 μm diameter. In three experiments comparing supplementation of the basal diet with 2·0 g Mg as either magnesium hydroxide or as one of the three separate purchases of the commercial calcined magnesite sources, the powdered magnesium hydroxide had the highest mean apparent availability coefficient (0·30) (faecal increase method). The corresponding values were 0·24 (Agma and Navarras), 0·20 (Chinese) and 0·15 (Greek) (pooled s.e. 0·014, d.f. 10). Powdered magnesium hydroxide also had the highest (0·18) mean availability coefficient (urinary increase method) compared with 0·12 (Agma), 0·13 (Navarras), 0·14 (Chinese), 0·10 (Greek) (pooled s.e. 0·005, d.f. 10). In two subsequent experiments, Agma had a superior apparent availability coefficient (0·26) (faecal method) than either the Chinese (0·14) or the Greek materials (0·19). A finer grade of Greek calcined magnesite (0·25) was equivalent to Agma. For the 12 calcined magnesites evaluated in the three main experiments, significant (P<0·05) correlations (r) were found between the magnesium availability coefficient (faecal method) and loss on ignition (−0·65); particle size proportions (<250 μm, 0·59; and >1000 μm, −0·65) and tended towards significance for rumen solubility in 24 μm nylon bags in hay-fed cows over two days (r=0·54, P=0·07) and rate of reaction with citric acid (0·57, P=0·055). No correlations were found with magnesium availability coefficients (urinary increase method). This confirms the limitations of both in vitro predictions and in vivo (faecal) estimates of magnesium availability for different calcined magnesites. The mean magnesium availability coefficient (faeces) of the 17 calcined magnesites was 0·21 (s.d. 0·05). If this were to be confirmed by other observations, it would have implications for the amounts of dietary calcined magnesite required to meet recommended dietary magnesium allowances for ruminants.

A general equation for predicting the movement of interacting and non-interacting solutes is proposed. Equations to predict the leaching fractions and mean displacement depth of linearly adsorbed solutes have been derived from the solution of the general equation. A simple equation which considerably reduces the experimental and analytical work has also been derived to evaluate the adsorption coefficient. The predicted adsorption coefficient compares favourably with published data.

1. It is possible for a breed of cattle to persist and to expand slowly, despite the existence of a genetic defect which prevents 50% of the calves born being used for breeding. Moreover, it is possible to exert a certain amount of selection in such a breed. The Dexter breed provides an example.

2. Before 1924, about 64% of entrants to the breed were from inspected animals. Between 1924 and 1939 the breed contracted. From 1940 to 1947 the breed expanded.

3. During the period of decline almost every Dexter-type female born was registered and raised. The wastage rate and age distribution of the cows are similar in Dexters to those of other breeds. There would appear to have been comparatively little breeding from Kerry types. The average registered reproductive rate of Dexter-type females was about 0·8.

4. While it was not possible to examine the breed structure in the period of expansion, this was probably accomplished by lengthening the average productive life of the female, and possibly also by breeding from Kerry types.

5. The possibility of exercising selection in Dexters is shown to exist. Only about 13% of the females registered are used for producing registered bulls. Of the total bull crop, only about 7% are used to produce registered females, but the bulls selected have different numbers of offspring. The use of bulls selected after progeny testing is hardly feasible in Dexters. The increased numbers of females necessary in order to produce an adequate number of heifers, renders this technique almost impossible.

6. There has been little inbreeding in Dexters. This is possibly due to deliberate policy, as some of the breeders associate inbreeding with the production of monstrous calves.

7. It would, therefore, appear that the damaging effect of a lethal in a breed could be overemphasized.