Manufacturing properties and quality of Cheddar, Wensleydale and Cheshire cheeses made either with milk from cows treated with Sometribove, methionyl bovine somatotropin (BST), or with milk from untreated control cows were compared.

The source of milk did not affect manufacturing properties in terms of processing time. Renneting times for Cheddar cheese made from control milk and that made from milk produced by cows treated with BST were 57 and 55 min, respectively. Corresponding values for Wensleydale and Cheshire cheeses were 50 and 53 min and 49 and 46 min, respectively. The source of milk did not influence cheese composition in terms of moisture, fat, protein and salt. When cheeses were submitted to the National Grading Service, those made from milk produced by BST-treated cows were indistinguishable from those made from control milk. The total points scored (maximum 100) for Cheddar, Wensleydale and Cheshire cheeses made with milk from control and BST-treated cows were 89 and 88, 85 and 85, and 86 and 86, respectively.

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.

The pigeon pea (Cajanus indicus or C. cajan) grown extensively in India, Africa, and other tropical and semitropical countries has attained considerable prominence as a stock food in Hawaii, where it is being grown as an important field and pasture crop in some sections. Its culture and utilisation in Hawaii have been exhaustively treated in a bulletin of the Hawaii Agricultural Experiment Station written by F. G. Krauss(1).

Bleasdale & Nelder (1960) refer to several models which have been used in studying the relationship of yield and density in crop plants and indicate that they regard as most satisfactory the equation:

where ω = yield/plant, ρ = number of plants/unit area and A and B are constants. The estimation of the constants for any given case is a very unattractive arithmetic exercise requiring a fairly large number of observations and a tedious iterative calculation; Nelder (1961) has discussed the least squares fit with the equation in the form

which may readily be derived from (1) by the substitutions

The data in the present case do not justify attempting this process but some progress can be made by the substitutions

by means of which it is easy to derive from (1) that

1. The object of this investigation was to determine the extent to which the decomposing power of soils within a climatic region is influenced by:

(a) the geological character of the rocks from which the soils are derived,

(b) the nature of the vegetative covering.

2. A short account is given of the geography, climatology, geology and pedology of Glamorgan. The soils of South Glamorgan appear in general to be Brown Earth types.

3. In studying the rate of decay it is necessary to obtain an index of the intensity of the total biochemical processes taking place. One of the best and most suitable of indices for this purpose is CO2 evolution.

4. A type of apparatus used by a previous investigator (Neller) to measure the CO2 evolved from soil was tested and found to be unsatisfactory. Thus a suitable apparatus had to be evolved. This apparatus is described in detail.

Three pot experiments were performed in unheated glasshouses at the University College of North Wales College Farm, Aber, Gwynedd in 1980–1983. Two experiments tested the effects of sowing date and N supply, the third sowing density and nitrogen supply. Extension growth of main-stem leaves was measured by ruler and expressed in thermal time units to allow comparisons between sowing dates. Rate and duration of leaf extension were determined from linear regressions of leaf length against thermal time.

Increasing N supply increased leaf extension rate but had no significant effects on leaf extension duration. Leaf extension rate increased with leaf position on the main shoot, but decreased slightly in leaves extending at the time of stem elongation. Leaf extension duration also increased with leaf position on the main shoot and was related to mean temperature during the leaf extension phase. Plants sown in September were able to compensate for lower radiation receipts by having a faster rate and longer duration of leaf extension, by producing larger leaves with a greater specific lamina area and by partitioning a greater proportion of extension growth into lamina and less into sheaths. In plants sown in June, the largest leaf occurred at a lower stem node and leaves emerging later showed a strong response to N. It is suggested that this is attributable to earlier onset of internal competition for assimilates. Variation in leaf extension rate was the main factor influencing variation in final leaf area. There was a strong positive relationship between leaf extension rate and leaf N content.

Increasing sowing density increased the area of the first four leaves on the main shoot and decreased that of later leaves, changes mainly associated with changes in leaf extension duration. It is concluded that progress in the modelling of leaf area expansion, light interception and dry matter production requires more information about how sowing date, sowing density and N supply interact to influence crop development and leaf growth.

1. Loss of ignition at 450°C. and the organic carbon content of some shale soils are positively correlated (r = +0·99).

2. Base exchange capacities and exchangeable cations were determined on soils, treated and untreated with hydrogen peroxide solution.

3. Oxidizing the organic matter lessened the exchange capacities of all samples; the exchange capacity of the organic matter varied from 67·5 to 97·0 m-equiv./1OO g. dry material.

An account is given of artificial insemination of 733 grade cows in Kenya from January 1936 to August 1939. 76·8% of the cows inseminated calved, with an average of 1·88 inseminations per conception. The different doses and dilution of sperm used gave very similar results, as did two inseminations, compared with one insemination, in a single heat period.

1. Continuous waterlogging and 4 weeks' waterlogging immediately after transplanting produced plants with higher leaf and shoot numbers.

2. There was no difference in the final shoot number between plants continuously waterlogged and those waterlogged for 4 weeks, immediately and 4 weeks after transplanting. The shoot mortality was higher in the continuously waterlogged plants and those waterlogged for 4 weeks immediately, 8 weeks and 12 weeks after transplanting than in those waterlogged for 4 weeks, 4 weeks after transplanting.

3. Continuously waterlogged plants and those waterlogged for 4 weeks, 4 weeks after transplanting, were taller than those waterlogged for 4 weeks, immediately, 8 weeks and 12 weeks after transplanting.

4. Leaf area per bucket, leaf area per shoot and per leaf lamina were higher in continuously waterlogged plants and those waterlogged for 4 weeks, 4 weeks after transplanting, than in those waterlogged for 4 weeks immediately, 8 weeks, and 12 weeks after transplanting.

5. Continuous waterlogging and waterlogging for 4 weeks, 4 weeks after transplanting, increased the physiological age of the plants as evidenced by earlier ear emergence and grain ripeness.

6. Fresh-weight yield, yield of grain and panicle were greater in continuously waterlogged plants and those waterlogged for 4 weeks, 4 weeks after transplanting, than in those waterlogged for 4 weeks immediately, 8 weeks and 12 weeks after transplanting.

7. The critical period for waterlogging in the cultivation of the rice variety studied is 4 weeks after transplanting and waterlogging applied during this critical period for 4 weeks favours higher yield of grain than when applied for the same period earlier or later than this period. Where water supply is limited the plants should only be waterlogged at this period and the soil kept moist throughout the remaining growing period. However, where there is enough water to waterlog the plants for 8 weeks this should be started immediately after transplanting.

A method that allows the effect of temperature treatments on plant quality to be quantified is described. The proposed method is based on the analysis of temperature regions for plant quality characteristics and enables an easier and more precise analysis of the influence of day and night temperature on plant growth and development. Plant quality may be evaluated by the combination of any number of plant characteristics. The proposed method can assist growers in determining what temperature regimes are necessary to produce acceptable-quality crops on specified days.

Steers fed low nitrogen diets were infused intraruininally with water.

Increasing the water load increased the urine volume and urinary urea excretion and depressed the plasma urea level.

The effect of intraruminal water loading was studied in association with intravenous urea loading of 25 and 65 g N/day. When 25 g N/day as urea was infused intravenously, water loading did not significantly increase the urinary urea excretion but the plasma urea level was depressed. At 65 g N/day water loading increased the urinary urea excretion and decreased the plasma urea level.

Significantly different relations between plasma urea and urea load existed for the ad lib. water and the water-loaded treatments but the relation between rumen ammonia level and plasma urea level was not affected by the water loading.

The results are discussed with reference to the recycling of urea.

The relationship between rate, spray interval and number of applications of Decis for pest control in cow pea was investigated. In 1978 and 1979, neither the rates nor the interaction effects were significant in grain yield when 12·5 and 25·0g a.i./ha of Decis were applied three times weekly or twice at intervals of 10 or 14 days.

Further trials in 1980 showed that for the contro l of thrips (M. sjostedti), rate, interval and number of applications were significant for samples at 49 days after planting and beyond, suggesting that the residual life of Decis is about 10 days. Three applications were significantly better than two for lowering the population of C. tomentosicollis and the number × interval interaction was also significant. The number, rate and interval were significant without interaction effects for shrivelled pods caused by all hemipteran pests. In all the trials in 1980 and 1981, damage by the pod borer M. testulalis was low. Rate and number × interval interaction were generally significant but no differences were observed in grain yield. However, in 1980 the higher rate and three applications gave better quality crop, resulting from less hemipteran damage.

An analysis of cost–benefit of the trial showed that 12·5 g a.i./ha gave higher returns than 25 g, as did two applications than three, but the trend in the spray interval was less consistent.

Cultivated pastures in southern China are being used to improve forage productivity and animal performance, but studies on grazing behaviour of goats in these cultivated pastures are still rare. In the current study, the grazing behaviour of Yunling black goats under low (5 goats/ha) and high (15 goats/ha) stocking rates (SRs) was evaluated. Data showed that the proportion of time goats spent on activities was: eating (0.59–0.87), ruminating (0.05–0.35), walking (0.03–0.06) and resting (0.01–0.03). Compared with low SR, goats spent more time eating and walking, and less time ruminating and resting under high SR. Goats had similar diet preferences under both SR and preferred to eat grasses (ryegrass and cocksfoot) more than a legume (white clover). The distribution of eating time on each forage species was more uniform under high v. low SR. Bites/step, bite weight and daily intake were greater under low than high SR. Results suggest that the SR affects grazing behaviour of goats on cultivated pasture, and identifying an optimal SR is critical for increasing bite weight and intake.

The writers do not mean to infer that the maintenance requirement of the adult sheep, as calculated by Wood and Capstick, is incorrect. The value obtained by these investigators is probably as reliable as any other which could be calculated from their data. The writers fully agree that Wood and Capstick's value is probably more accurate than previously estimated values of the maintenance requirement of the adult sheep.

1. Selections from a cross of varieties of Triticum vulgare and T. Turgidum have been backcrossed repeatedly to the turgidum and vulgare parents and selections of turgidum and vulgare type respectively made within each series.

2. The yield and morphological stability of turgidum- and vulgare-type selections from the straight cross have been compared with those of selections backcrossed up to four times to T. turgidum and T. vulgare respectively.

3. In the case of backcrosses to T. Turgidum the highest yielding selections have been derived from the most frequently backcrossed material, but the vulgare-type selections from the straight cross have outyielded those from the material backcrossed to T. vulgare.

4. An analysis of the yield components of the parents and of the most promising selections, in terms of ears per plant, spikelets per ear, grains per spikelet and 1000-grain weight, has shown no evidence of a combination of the characters determining the high yield of the parents in these high yielding selections.

Response to selection primarily for lint yield among spaced plant populations of four American and one African variety of Gossypium hirsutum L., established in 1965—6 at Kimberley Research Station, was studied in three experiments conducted between 1966 and 1970.

In the first experiment, in which single-hill micro-plots of 3–5 plants per hill were used, the mean lint yield of progenies was larger than predicted from single plant heritabilities. In the second experiment, in which single-row plots were used, response to selection for lint yield was generally less than expected. In the third experiment, in which three-row plots were used, response to selection for lint yield was again less than expected and less than manifested in the second experiment. However, in all experiments responses to selection for lint percentage, lint quality properties, and height were close to expectations while some individual progenies substantially out-yielded their unselected parents.

The progressive decline in response to selection for lint yield from the first to thethird experiment, and the discrepancies between the actual responses and the expected responses for lint yield in all experiments, were interpreted mainly on a basis of intergenotypic competitive effects differing in sympathy with plot size and plant disposition.

It was concluded that the objective methods of selection practised were successful when judged on plant breeding criteria. It was also concluded that intra-varietal selection is an important technique by which genetic improvement can be achieved at regional breeding centres with limited resources.

The influence of dietary nutrients on carcass composition, rate of tissue deposition and the development of specific tissues, major and minor muscles in particular has been well documented for pigs reared in a temperate environment. Attempts have also been made in this environment to simulate artificial tropical conditions and, on the consequence of such conditions, to predict the nutrition and growth of the pigs.

Seven non-destructive field measurements were made on 1270 pigeon-pea plants varying widely in age, size and plant type, before determining their dry weight. The non-destructive measurements were generally highly correlated with one another, and were all significantly correlated with total, total above-ground and structural dry weights. In one experiment dry weights were best predicted by a multiple regression using stem diameter, length of longest branch and number of branches as predictors. Field height and stem diameter were the best predictors in a second trial. It is suggested that dry weights can be estimated by taking certain measurements at regular intervals, simultaneously sampling a number of plants to determine the best predictive equation. Where it is unnecessary or impracticable to do this, stem diameter appears to be the best single index of dry weight.

Cultivar mixtures of winter barley and spring barley, together with their component monocultures, were grown in field trials to assess the effect of cultivar combinations on both straw and grain yield. The overall grain yields for all trials were significantly higher for the cultivar mixtures than for the corresponding component monocultures. Also, significant decreases in rhynchosporium disease severity for cultivar mixtures were recorded for most non-fungicide treatments. The size of these responses was often significantly correlated with the component number of the mixtures. The amount of straw produced in mixtures was sometimes changed significantly, but not always in a positive direction and it was only correlated with increasing mixture component number in two environments. No correlation of straw yield potential of cultivars with performance in mixtures was found. Cultivar × cultivar mixture × environment interactions appeared to affect the relative yield of grain and straw differentially and therefore it was not possible to predict the effect of mixtures on the harvest index.

The use of silvopastoral systems with tree legumes is a viable alternative to recover and develop pastures, as they add N to the system influencing pasture growth. This study hypothesized that the herbage and litter of signalgrass (Urochloa decumbens Stapf) is affected by legume trees in the pasture. Treatments were composed of (1) signalgrass + Mimosa caesalpiniifolia Benth.; (2) signalgrass + Gliricidia sepium Jacq.; and (3) signalgrass monoculture. The 3-year experiment followed a randomized complete block design with three replications. Tree legumes were planted in double rows (15 × 1 × 0.5 m), in 1 ha paddocks. Litter samples were taken in five distance points (0, 1.8, 3.7, 5.6 and 7.5 m) perpendicular to tree legume rows. Signalgrass was taller at longer distances from the trees (P < 0.05). Signalgrass height differed between treatments, with taller signalgrass found in pastures mixed with G. sepium (15.6 cm) compared to M. caesalpiniifolia (9 cm) (P < 0.05). Herbage N content decreased with increasing distance from tree rows (P < 0.05). Litter N content followed a similar pattern, ranging from 23 g/kg under the trees to 12 g/kg at 7.5 m away from tree rows. Signalgrass did not grow under the tree crown (0–1.8 m), especially when intercropped with M. caesalpiniifolia. The findings of this study suggest that the type of legume trees used in the silvopastoral system has the potential to modify the pattern of grass growth and content of N in pasture litter.