The distribution of body water in the different body compartments of four highpotassium (HK) and four low-potassium (LK) type sheep of the Marwari breed of the Rajasthan desert was determined after imposing the following watering treatments, viz. watering ad lib., ¼, ½ and ¾ restrictions (each of five days ‘duration with a sevenday normal drinking regime between each treatment) and water deprivation (of three days’ duration). There was no difference in the voluntary water intake of the HK and LK animals. The HK animals normally have a higher blood and plasma volume status than the LK. In both types of animals, the total body water, total blood and plasma volumes and the extracellular, intracellular and interstitial fluid volumes started decreasing as water intake was reduced below 25% of the daily requirement. In both the phonotypes 75% reduction was similar in its effect to complete deprivation. The physiological status of the HK Marwari animals appears to be somewhat superior to that of the LK although both types seem to be equally adapted to the conditions of the habitat.

The growth and yield of four varieties of field beans were studied in field experiments in 1967 and 1968.

Seed yield of the varieties Albyn Tick, Herz Freya, Blue Rock and Maris Bead were similar (averaging 6600 kg/ha) in 1967, but in 1968 Albyn Tick and Herz Freya (averaging 6400 kg/ha) outyielded Maris Bead (5700 kg/ha). Yield in both seasons were substantially more than the national average yields for Britain (about 3000 kg/ha). In 1968, yields were 40% greater at 57 plants/m2 (7100 kg/ha) than at 36 plants/m2 (5100 kg/ha).

Yield was closely correlated with number of pods/plant. The number of pods/node regulated this rather more than the numbers of nodes forming pods. Mean seed weight and seed number/pod varied little between plant densities but variety means were significantly different.

Maximum numbers of immature pods were present in late June. By mid-July 35% of the immature pods had shed, mainly from the middle and top of the range of podbearing nodes.

Dry weight per unit area was related to plant density differences and leaf area duration (LAD) up to pod-setting (late June). Total dry weight and seed dry weight at maturity were not related to total LAD or LAD after pod setting. Seed yield at a node was closely correlated with leaf area at the same node (r = 0·67 to 0·94).

Differences in net assimilation rate (NAR) between varieties were not significant. A substantial rise in NAR in July-early August was attributed to additional photosynthesis by pods.

Comparative slaughter was used to assess the effects of body-weight loss on Brahman cross (BX) and Africander cross (AX) steers of the F3 generation with respect to the empty body weight, the hot carcass weight and various offal components. Animals were slaughtered at design weights of 325, 341, 358, 374 and 390 kg, some while during positive body-weight growth (Group A) and others during weight loss from 390 kg at a rate of 0·5 kg per day (Group B).

AX animals had less empty body weight (B. B. W.) and dressed carcass weight (H. C. W.) at the same fasted body weight. Weight loss also reduced the amount of E. B. W. at the same fasted body weight but the effect on H. C. E. was not significant.

The breeds were very similar with respect to the various components of the offal, except that the AX had heavier heads. The weight loss treatment increased the proportion of the head, tail and feet, because these comparatively bony structures lost relatively little during the weight loss period. The heart was also relatively increased by the weight loss treatment. The liver, gall bladder, kidneys, total gut tissue, spleen and thymus were reduced relative to E. B. W. in Group B animals. The liver showed its most rapid weight loss in the early period of body-weight loss, being the only organ to show any variation in its rate of change during body-weight loss.

Body-weight loss caused changes in the distribution of the gut tissue, with a relative loss in the rumen-reticulum and a relative gain in the hind gut.

In some plants the roots have been shown to be major sites of cytokinin production. The part they play in controlling growth and development of cereals was studied by spraying barley with kinetin solution and by changing the size of the root system. Two varieties of barley were grown in culture solution and kinetin was applied and root sexcised at the second-, third- or fifth-leaf stage. The kinetin in aqueous solution was sprayed on the leaves, and either most of the root-tips, or an equivalent weight of entire root strands, were removed. Kinetin increased both shoot apex development and the final ear size. The weights of the main shoot and the whole plant also wore increased, particularly by the later treatments. Removing entire root strands decreased the whole plant dry weight more than removing most of the root apices, but the main shoot weight was less affected. Kinetin interacted with root removal, though neither the interaction nor the main effect of root removal showed unequivocally that cereal roots are the site of cytokinin synthesis, possibly because new root tips were regenerated.

Forty merino sheep of mixed ages including lambs, ewes, wethers and rams were slaughtered and dissected. The chemical fat content often muscle groups in each sheep was measured directly and the mean value for the musculature of the whole carcass calculated.

A characteristic pattern of chemical fat deposition was shown with the intercostal muscle group and the abdominal group being consistently highest in fat content, the shin and hind-limb muscles lowest and other intermediate. The pattern of growth of intramviscular fat was consistent with differences in activity of the muscle groups in the maintenance of posture. It was postulated that variations in fat content in muscle groups are affected by differences in blood flow.

A highly significant relationship was established between dry matter and chemical fat content for each of the muscle groups. The regression was characteristic for each muscle group, and differed for most groups.

Regressions between individual muscle group fat and that of total musculature fat revealed that no group was consistently the best predictor of the total carcass musculature fat though there was considerable difference between the groups. It was concluded there is no group which could be used for prediction purposes commercially.

In a group of 14 other ewes subjected to weight loss up to 30%, and half of which were implanted with resorcylic acid lactone, no discernible effects on muscle group fat content were revealed.

Crops of lucerne and cocksfoot of high moisture content were ensiled without additive and with the addition of formic acid at up to 0·91% of the fresh crop weight in test-tube silos and in silos containing about one tonne of crop. Silages from the larger silos were fed to sheep for measurement of voluntary intake and digestibility.

Silages made without formic acid were badly preserved and contained large quantities of acetic acid, butyric acid and ammonia. The addition of formic acid reduced the production of acids and ammonia. With test-tube silos differences between the minimum pH measured during the storage period and the final pH after 155 days were not significant for silages made from both crops with addition of 0·45% or more of formic acid: these silages were considered to be stable.

Silages from the larger silos were generally not as well preserved as those from the test-tube silos, particularly at the higher levels of formic acid application. This difference was attributed to less effective application of additive to the larger silos and loss of formic acid in the effluent which was released from these silos but not from the test-tubes. Organic matter intake increased with increase in formic acid level, but organic matter digestibility was not significantly correlated with formic acid levels. Intake was closely related to the quantity of ammonia in the silage and it is argued that formic acid affected intake by influencing the pattern of fermentation in the silo rather than by a direct effect of formic acid itself.

Wool samples from 47 Barki yearlings were taken from five positions during two years to study the variability in the fleece, the cause of variability and associations between different fleece traits. Statistical analysis has indicated the following significant points.

An antero-posterior gradient occurred in the different traits under study. When medullation was discarded, though it was of a low magnitude (3·9%), a reduction of 5·89% in the mean fibre diameter and of 18·33% in its standard deviation occurred.

The position most representative of the whole fleece varied with the trait. It is recommended to take three sampling positions forming a triangle, withers, mid-side and hip, to represent the Barki fleece.

The animals contributed the major part in the variability of mean fibre diameter (1), the standard deviation of fibre diameter (S.D.1), percentage medullation, mean fibre diameter after discarding the medullated fibres (2), the standard deviation of fibre diameter after discarding the medullated fibres (S.D.2), the contribution of medullation to the total variability, percentage fine fibres and percentage coarse fibres. The positions were the main contributor to the variability of percentage kemp fibres, staple length, medullation index and to a certain extent to that of the kemp score. The year played a significant part in the variability except for 2 and S.D.2.

The highest correlations with the standard deviation of fibre diameter were those of percentage medullation and kemp score. These three variables when considered separately accounted for 0·47, 0·35 and 0·31 respectively of the variability in S.D.

Equations were obtained to predict the standard deviation from both the mean fibre diameter and the percentage medullation and to predict the mean fibre diameter from the staple length and the kemp score. The coefficient of determination of the first set of equations ranged from 0·47 to 0·56 while that of the second set ranged between 0·07 and 0·51 for different positions.

Twelve experiments in the East of Scotland tested a hypothesis that the smaller yield responses to salt in Scotland than in England shown by previous work was due to the adverse effects of soluble salt concentration brought about by ridging, and also to test a wider range of salt and potash than used previously. All combinations of three rates of salt (0, 315, 630 kg/ha) and three rates of muriate of potash (0, 315, 630 kg/ha) were applied in four ways: (1) ploughed down in winter, (2) on the furrow in February, (3) in the seed bed and (4) half as (1) and half as (3). Plant emergence was decreased by salt and potash in only three experiments and then only when the larger amounts of both fertilizers together, along with nitrogen and superphosphate, were applied in the seed bed prior to ridging. Both experiments were in a year when the weather was dry while the plants emerged. Yield of sugar was greatest with the February application on the furrow and smallest with the ploughing down method. At equal weights, salt and muriate of potash had similar effects on sugar yield. Equations derived from the response surface gave the most profitable dressing as 377 kg/ha of salt plus 127 kg/ha of K2O which gave a £4.90 greater margin per hectare over costs than the best potassium application without salt.

Field trials were carried out for three years in the savanna zone of northern Ghana to determine the fertilizer requirements of yam (Dioscorea rotundata). Under the conditions of the experiment, K was not important in yam fertilization. Release from the exchangeable reserves was adequate in meeting the crop demand. A small positive response to P applied at low levels (33·6 kg/ha) was observed and averaged only 5·6% increase in yield. N was the most important nutrient element and its application increased yields highly significantly. On the average, application of 33·6 kg/ha gave an increase of 13·5% and 67·2 kg/ha gave a 22·1% increase in yield. More N did not further increase yield.

Response of wheat to fertilizer-P on soils low and medium in available P increased with increasing doses up to 26 kg P/ha; responses were proportionately greater on medium-P soils. Application of 39 kg P/ha increased the response slightly on low-P but decreased it drastically on medium-P soils. The relatively small response on low-P soils may be due to fixation of fertilizer-P. The results indicate that the maximum response to fertilizer-P may be obtained only when P fixing capacity of the soil is satisfied so that sufficient P for the crop remains in the soil solution. The results of this investigation suggest that fertilizer should be applied on the basis of soil test data of individual fields instead of following regional recommendations.

Fatty acid composition of tail fat (TF), kidney fat (KF) and subcutaneous fat from the rumps (SCF) of docked and intact fat-tailed Awassi sheep was studied.

Docking had no effect on the composition of KF. Kidney fat possessed harder characteristics due to its relatively higher content of saturated fatty acids as compared with SCF or TF.

A series of digestibility trials was conducted with non-lactating cows and adult castrated male sheep given diets of hay and dried or high-moisture maize grain in various physical forms. Sheep were able to digest all forms of maize well and to a greater extent than cows. In cows considerable variation in digestibility of maize was associated with the particle size of the maize and the individual animal. Maximum digestibility of dried maize in cows ensued when the modulus of fineness lay within the range 4·7–3·0 and with high moisture maize from 5·4 to 5·1. A study was made of the effect of particle size on the rate of digestion of maize suspended in nylon bags in the rumen. Evidence was presented showing the importance of rumination in ensuring the digestion of intact kernels. Possible causes of differences between cows in their ability to digest intact maize kernels are discussed.

The fen silts bordering the Wash are among the most important soils for crop production in eastern England. Derived from marine alluvial deposits occurring naturally or as a result of reclamation, they form deep almost stoneless soils containing little coarse sand but much fine sand and silt.

Seven textural classes, ranging from loamy fine sand to silty clay, can be distinguished, but these can be grouped into (1) light silts, typically deep very fine sandy loams with a large available water-holding capacity but weakly developed structure; (2) medium silts, silty loams; and (3) heavy silts, silt loams or silty clay loams, less porous and more retentive of moisture than the light silts.

Formerly under grass, the silts were at first capable of growing good crops of potatoes with P fertilizer alone, but as their organic-matter content decreased, potatoes became increasingly responsive to N.

In 18 potato manurial experiments on silt soils in Holland, Lincolnshire, done between 1953 and 1963, the mean response to N was much larger than on most English soils, but response differed greatly from site to site and year to year; in most trials N was particularly effective in increasing tuber size and yield of ware. With long-continued use of P fertilizer, residues have accumulated and, particularly on light and medium silts, responses were quite small and differed little between sites; P tended to increase tuber numbers, and so to decrease ware percentage. Most silt soils are rich in K, and only small responses to K fertilizer can be expected, but on a few sites on the light silts, identified by soil analysis as being comparatively poor in K, potatoes responded well. Using these experimental results, recommendations are given for the manuring of potatoes on silt soils.

Cooking tests showed little consistent effect of manurial treatment on the amount or degree of tuber blackening.

Food intake prediction relationships were developed from in vitro dry-matter digestibility determinations on food and resultant faecal material for a number of diets ranging from low quality roughage to high quality irrigated pastures.

The relationship between true digestibility in vitro and in vitro food dry-matter digestibility was curvilinear, although true digestibility of food dry matter in vivo was highly correlated with apparent digestibility of food dry matter in vivo. The latter relationship was linear.

For 122 sheep observations on voluntary dry-matter intake incorporating 11 diet types, introduction of either of the terms, cell-wall concentration in food: cell-wall concentration in the resultant faeces (CWFo/CWFe), or its converse, into conventional faecal index relationships did not increase precision of intake prediction using faecal nitrogen as an indicator substance. However, significant intake prediction relationships using food:faeces cell-wall ratios were generated.

Values for in vitro digestibility of food and resultant faeces dry matter expressed as either a ratio (R) or as a difference (delta) yielded useful prediction relationships. For ‘green’ and for ‘dry’ classifications of the feedstuff's investigated some of these new relationships were either equal to or superior to the predictive efficiency of conventional faecal index relationships.

Reasons are discussed for use of maximum potential in vitro digestibility values for food and faecal dry matter in such relationships in future work rather than a conventional 48 h fermentation.

Results from two trials on spring barley varieties are presented. A factorial fertilizer trial estimated the effects of N, P and K at each of three levels on diastatic power, heat-stable alpha-amylase activity, grain nitrogen content, thousand corn weight and yield in a single variety. This revealed that the main effect of N was the most important source of variation. In a subsequent variety–nitrogen trial seven varieties were tested at each of three levels of N.

In the variety–nitrogen trial, diastatic power was found to be positively correlated with both grain nitrogen content and alpha-amylase activity although these latter two variates were not themselves correlated. These observations were confirmed both within genotypes and within environments, and a hypothesis is advanced in explanation.

The implications of the results for a breeding programme directed towards the production of high-yielding, high-diastase varieties are discussed.

Drainage lysimeters were used to estimate actual transpiration of a perennial ryegrass sward; this is compared with the calculated values for potential transpiration. Losses to drainage of nitrate nitrogen (NO3–-N) under differing levels of application of nitrogen fertilizer were examined. When 250 kg N/ha were applied annually losses of NO3-N were negligible; when 500 kg N/ha were applied up to 142·9 kg N/ha were lost to drainage. Concentration of NO3-N in the leachate with an application of 250 kg N/ha was low (1–5 ppm); with 500 kg N/ha the concentration ranged from 10 to 109 ppm. Losses of NO3–-N were particularly severe during winter following a dry autumn. When drainage occurred during the growing season losses were minimal.

Concentrations and quantities of K, Ca, Mg, Na, P, Cl and S (as sulphate) leached wore also examined.

In experiments at this Institute in which samples of liver were required for the estimation of mineral content, difficulty had been encountered in obtaining samples reliably, especially in pregnant animals using the technique described by Dick (1944) and Abdellatif (1968). It was decided to investigate the possibility of obtaining liver samples from sheep under direct vision using a laparoscope.

Red blood cell electrolyte levels and haemoglobin types have been determined in flocks of Peppin Merino sheep genetically different for clean fleece weight and crimp frequency. The flocks selected for high clean fleece weight or low crimp frequency had significantly higher mean erythrocyte potassium levels than did those flocks selected for low clean fleece weight or high crimp frequency, this difference was apparent in both haemoglobin AB and BB types. Erythrocyte potassium concentration was not correlated with either clean fleece weight or crimp frequency within flocks. The high clean fleece weight flock had a significantly higher gene frequency for high potassium than did the low clean fleece weight flock, while the high crimp frequency flock had a lower haemoglobin B gene frequency than the low crimp frequency flock.

During 3 years, three groups of 20 Scottish half-bred ewes were grazed on perennial ryegrass, white clover or red clover. During this period the two legumes were oestrogenic, in terms of teat-length extension of wethers, but the perennial ryegrass was not. The white clover was only markedly oestrogenic when there was a high proportion of diseased leaves. The mean litter size and lambing percentage of the ewes grazed on red clover was significantly reduced. White clover, although it was oestrogenic, had no effect on mean litter size or lambing percentage. The mean litter size of the ewes on the perennial ryegrass was 2·35, 2·30 and 2·24, on the white clover was 2·20, 2·33 and 2·23 and on the red clover was 1middot;60, 1·67 and 1·78 for the three lambings. Lambing percentage of the ewes on the perennial ryegrass was 175, 225 and 218, on the white clover was 210, 222 and 189, and on the red clover was 160, 128 and 118 for the three lambings. The lambing date of the ewes grazing on the red clover was significantly later at the third lambing.