The digestibility and rumen metabolism of diets containing as 50% of their organic matter (OM), cotton straw (CS) untreated, treated with sodium hydroxide and treated with ozone, were studied in sheep cannulated in the rumen and at the duodenum with simple cannulae. The concentration of total volatile fatty acids (VFA) in the rumen of sheep given the ozone and NaOH treatments was higher than in the untreated diet; however, the VFA profiles were not different. The rumen dehydrogenase activity, suggested to reflect general microbial activity, was higher by 83 and 81% in the ozone and NaOH treatments respectively, than in the untreated.

Apparent digestibility of organic matter in the ozone-treated diet was 74·6%; 1·25 and 1·17 times higher than in the untreated and NaOH-treated diets respectively. The calculated values for organic matter and cell-wall digestibilities of the cotton straw in the complete diets were: 30·0, 20·0; 60·8, 60·0; and 39·6, 39·7%, respectively, for the untreated, ozone and NaOH-treated cotton straw. Nitrogen metabolism was not impaired by the presence of formic acid in the ozonated cotton straw; the apparent absorption of N from the intestine and the apparent digestibility of N were higher in the ozonetreated diet than in the untreated or NaOH-treated diet.

The proportion of organic matter and cell walls digested in the rumen was higher in the NaOH and ozone treatments than in the untreated, and the possible reasons for that are discussed. A positive relationship was found between cell-wall digestion in the rumen (% of intake) and the rate of passage (% per h) of particulate matter from the rumen. The interpretation of this relationship is discussed in general and in view of the results of the present study.

During the past century wheat breeders have produced a large number of genetically improved wheat lines and varieties. This activity has led to widespread adoption of improved varieties, a steady increase in average wheat yields during the past 4–5 decades and major contributions to food security and poverty reduction. The rate of generation and adoption of improved varieties, and therefore the time lag from varietal release to widespread use, varies across regions. The remarkable success of wheat improvement hinges on the decisions of millions of farmers to adopt, or replace older wheat varieties with superior material. The present paper summarizes studies on the determinants of adoption. Because adoption is a necessary but not sufficient condition for economic impact, the present paper synthesizes key assessments of impact from different farming systems in developing countries.

A field experiment to compare the growth, development and yields of four varieties of oilseed rape, Cresus, Guile, Rigo and Nilla, is described and the results discussed. Cressus was the highest-yielding variety largely because it produced more pods and more seeds per pod. The numbers of pods and seeds per pod were positively correlated with the leaf area index at the onset of flowering. This suggests that the rate of supply of carbon assimilates to the inflorescences around the time of anthesis is an important yield-determining character. The mean weight of the individual seeds was greater in Cresus than Guile and this difference, which developed late on in pod growth, also contributed to the higher yields in Cresus.

Selection for high-(H) and low-(L) drought-induced abscisic acid (ABA) accumulation in spring wheat was made from a cross between parents which contrasted in the character. By the F5 generation H and L selections were homozygous for ABA accumulation, which differed between the classes by 80%. The selections were evaluated in field experiments in which the amount of available water was varied.

In one experiment, in which plots were automatically sheltered from rain, H selections outyielded L selections by an average 0·36 t/ha both when fully irrigated and when water was withheld between anthesis and maturity. The extra grain yield of the H selections was not produced at the expense of additional water requirement in either treatment. When water was withheld during the 4 weeks preceding anthesis, the grain yields of H and L selections were similar, but H selections used less water between 1 May and maturity. Averaged over all treatments the ratio of grain yield to water use was greater for H selections than for L selections by 0·12 t/ha/100 mm. Withholding water caused a reduction in water use and a corresponding reduction in biomass production in both sets of selections.

In two trials in which plots were either irrigated weekly or received natural rainfall only, the ratio of grain yield to water use was again greater for H than for L selections, by an average 0·10 t/ha/100 mm.

It is concluded that in spring wheat, selection for high levels of ABA accumulation in response to water stress may provide an opportunity of increasing grain yield and water-use efficiency.

Three rates of phosphate (0, 25, and 60 kg/ha P2O5) were applied to phosphorus-deficient native grassland at Tel Hadya, in northern Syria, and biomass productivity, botanical composition and number of legume seeds in the soil were monitored for five seasons (1984/85–1988/89). The experiment was grazed at low (0·8 sheep/ha per year) and high (1·7 sheep/ha per year) stocking rates from the second to the fourth seasons of the experiment; in the fifth season, the low and high stocking rates were increased to 1·1 and 2·3 sheep/ha per year, respectively. The experimental site was typical of native grassland within the cereal zone of west Asia, where cropping is not possible because of shallow, stony soils and steep slopes.

The results showed that annual applications of phosphorus, even as low as 25 kg P2O5/ha, alleviated the deficiency in soil P and resulted in improved pasture production, even in dry years. Legume production showed the greatest response to P, increasing by 0·3–3 times the production of the control treatments. By the fifth season, legume seed mass had increased threefold and number of seeds sixfold in the P-treated plots, compared with the first season, while in the control plots there was little change. Rain-use efficiency on the P-treated plots was more than double that of the controls by the fourth and fifth seasons.

Practical application of the results depends on whether (i) legumes are as frequent in native grasslands, as a whole, as they are at Tel Hadya, (ii) the P deficiency observed at Tel Hadya is widespread, and (iii) grazing of communally owned grasslands can be controlled. It is suggested that all three criteria will often be fulfilled and, therefore, that grassland productivity in west Asia could be substantially increased. Furthermore, the results suggest that above-ground cover and soil organic matter will also increase after P application, both of which will help to reduce soil erosion and thereby increase the sustainability of livestock production in west Asia.

A dynamic, mechanistic model of enteric fermentation was used to investigate the effect of type and quality of grass forage, dry matter intake (DMI) and proportion of concentrates in dietary dry matter (DM) on variation in methane (CH4) emission from enteric fermentation in dairy cows. The model represents substrate degradation and microbial fermentation processes in rumen and hindgut and, in particular, the effects of type of substrate fermented and of pH on the production of individual volatile fatty acids and CH4 as end-products of fermentation. Effects of type and quality of fresh and ensiled grass were evaluated by distinguishing two N fertilization rates of grassland and two stages of grass maturity. Simulation results indicated a strong impact of the amount and type of grass consumed on CH4 emission, with a maximum difference (across all forage types and all levels of DMI) of 49 and 77% in g CH4/kg fat and protein corrected milk (FCM) for diets with a proportion of concentrates in dietary DM of 0·1 and 0·4, respectively (values ranging from 10·2 to 19·5 g CH4/kg FCM). The lowest emission was established for early cut, high fertilized grass silage (GS) and high fertilized grass herbage (GH). The highest emission was found for late cut, low-fertilized GS. The N fertilization rate had the largest impact, followed by stage of grass maturity at harvesting and by the distinction between GH and GS. Emission expressed in g CH4/kg FCM declined on average 14% with an increase of DMI from 14 to 18 kg/day for grass forage diets with a proportion of concentrates of 0·1, and on average 29% with an increase of DMI from 14 to 23 kg/day for diets with a proportion of concentrates of 0·4. Simulation results indicated that a high proportion of concentrates in dietary DM may lead to a further reduction of CH4 emission per kg FCM mainly as a result of a higher DMI and milk yield, in comparison to low concentrate diets. Simulation results were evaluated against independent data obtained at three different laboratories in indirect calorimetry trials with cows consuming GH mainly. The model predicted the average of observed values reasonably, but systematic deviations remained between individual laboratories and root mean squared prediction error was a proportion of 0·12 of the observed mean. Both observed and predicted emission expressed in g CH4/kg DM intake decreased upon an increase in dietary N:organic matter (OM) ratio. The model reproduced reasonably well the variation in measured CH4 emission in cattle sheds on Dutch dairy farms and indicated that on average a fraction of 0·28 of the total emissions must have originated from manure under these circumstances.

Conservation agriculture (CA) is inadequately developed for rice-based cropping systems widely practiced in Bangladesh. The current drawback is the implementation of CA for all crops including rice (Oryza sativa L., ecotype ‘transplanted aman’ [T. aman]) to increase rice–wheat (Triticum aestivum L.) rotation productivity. It is important to identify the best combination of tillage types and cropping systems to achieve a high yield of component crops and improve soil health. Three tillage practices, assigned to main experimental plots [namely, zero tillage (ZT), conventional tillage using a rotary tiller (CT) and deep tillage using a chisel plough (DT)] and three different cropping systems, assigned to sub-plots [namely, WFT: wheat–fallow–T. aman, WMT: wheat–mungbean (Vigna radiata L. Wilczek)–T. aman and WDT: wheat–dhaincha (Sesbania rostrata)–T. aman], were tested. After 4 years, ZT under WDT and WMT significantly increased soil organic matter (SOM) at 0–150 mm depth, and these replicates also held the highest levels of total organic carbon. Soil organic carbon (C) increased at a rate of 1.17 and 1.14 t/ha/y in ZT under WDT and WMT, respectively, while CT and DT under WFT were almost unchanged. After 4 years, SOM build-up by the three-crop system (WDT and WMT) under ZT helped conserve soil moisture and improve other soil properties, such as reduction in soil strength and bulk density and increase plant available water content, thus maintaining an optimum soil water infiltration rate. Zero tillage under WMT and WDT showed significant improvements in root mass density of rice and wheat at increased soil depth. The WDT and WMT plots under DT consistently gave the highest yield followed by WDT and WMT under CT, in contrast with ZT under WMT or WDT, which showed the highest improvement in crop yields over the years. In summary, minimum soil disturbance together with incorporation of a legume/green manure crop into the rice–wheat system as well as the retention of their residues increased soil C status, improved soil properties and maximized grain yields.

Seed yield and seed quality determine much of the value of rice (Oryza sativa L.) crops to the producers. The effects of genotype and environment on seed yield and quality were investigated using 12 rice genotypes grown during 3 years (2000–2003) at four different sowing dates in India, where detailed environmental data were collected. Yield, seed weight, proportion of seed setting and quality in terms of potential seed longevity, proportion of discoloured seeds, seed leachate conductivity and percentage germination were evaluated. The results were subjected to analysis of variance and the influence of environmental factors was evaluated by correlation analysis. Analysis of variance suggested that proportion of seed setting, seed leachate conductivity, potential seed longevity, percentage seed germination and proportion of seed discoloration were influenced more by environmental effects than by genotypic effects. In contrast, yield, panicle number, seed weight, and proportion of high-density grains were influenced more by genotypic than by environmental effects. The significant interaction effects of genotype and environment for all characteristics were attributed to differential resistance of genotypes to lodging (caused by increased plant height, low radiation and excessive rain at the time of grain filling) and were associated with fewer panicles harvested, lower seed setting and lower seed weight. Correlation analysis suggested that warm weather conditions with high solar radiation and without excessive rains during grain filling stage gave the best rice seed yield with high quality.

Common bean (Phaseolus vulgaris L.) is the most important food legume for human consumption. Drought stress is the major abiotic stress limitation of bean yields in smallholder farming systems worldwide. The current work aimed to determine the role of enhanced photosynthate mobilization to improve adaptation to intermittent and terminal drought stress and to identify a few key adaptive traits that can be used for developing drought-resistant genotypes. Field studies were conducted over three seasons at Centro Internacional de Agricultura Tropical, Palmira, Colombia to determine genotypic differences in adaptation to intermittent (two seasons) and terminal (one season) drought stress compared with irrigated conditions. A set of 36 genotypes, including 33 common bean, two wild bean and one cowpea were evaluated using a 6 × 6 lattice design under irrigated and rainfed field conditions. Three common bean elite lines (NCB 226, SEN 56, SER 125) were identified with superior levels of adaptation to both intermittent and terminal drought stress conditions. The greater performance of these lines under drought stress was associated with their ability to remobilize photosynthate to increase grain yield based on higher values of harvest index, pod harvest index, leaf area index and canopy biomass. Two wild bean germplasm accessions (G 19902, G 24390) showed very poor adaptation to both types of drought stress. One small-seeded black line (NCB 226) was superior in combining greater values of canopy biomass with greater ability to mobilize photosynthates to grain under both types of drought stress. Two small-seeded red lines (SER 78, SER 125) seem to combine the desirable traits of enhanced mobilization of photosynthates to seed with effective use of water through canopy cooling under terminal drought stress. Pod harvest index showed significant positive association with grain yield under both types of drought stress and this trait can be used by breeders as an additional selection method to grain yield in evaluation of breeding populations for both types of drought stress.

Growth and water use of kabuli-type chickpea was measured during the 1982/83 and 1983/84 growing seasons in northern Syria under rainfed conditions. Winter-sown (November) and springsown (March) crops of cv. ILC 482 were grown in 1982/83 while in 1983/84 spring-sown crops of contrasting genotypes (ILC 482, ILC 1929 and ILC 3279) were compared.

In 1982/83, shoot dry matter and seed yields of the winter-sown crop were almost twice those of the spring-sown crop although the water use of both crops was almost the same. Root growth of both crops was most rapid before flowering but continued until maturity (early June) in the winter-sown and until mid to late pod filling (also early June) in the spring-sown crop. Root dry weight (c. 45 g/m2) and length (c. 45 cm/cm2) were similar in both crops during pod filling.

In 1983/84, shoot weight, root weight and root length were similar in all genotypes but the later maturity of ILC 3279 resulted in lower seed yield and hence harvest index, and greater water use.

The root length density decreased approximately logarithmically with depth in the soil profile although comparison between seasons and with other published results showed that the relations could not be used predictively. Water use efficiency was poorer in the second, drier season and was almost doubled by winter sowing.

Three experiments were conducted to determine the value of foliage from three tropical legume trees as low level protein supplements to napier grass diets for growing ‘Kacang’ goats. The average crude protein concentration in the napier grass was 12%.

Napier grass and foliage of the legume trees Gliricidia maculata, Leucaena leucocephala and Sesbania grandiflora were subjected to in situ microbial fermentation and subsequent treatment with acid-pepsin solution. The levels of N solubilized after 2 h incubation were 46 and 43% for napier grass and sesbania respectively, which were higher (P < 0·05) than those for gliricidia and leucaena (27%). Rates of protein disappearance between 2 and 24 h incubation in the rumen averaged 2·6%/h for the legumes and 1·0%/h for napier grass. The proportion of water-insoluble, rumendegradable protein from the legumes was larger (P < 0·05) than that from napier grass.

Napier grass intake by goats supplemented with gliricidia or leucaena at 15% of the dry-matter intake from napier grass was lower (P < 0·05) than that of controls receiving no legume supplement. Napier grass intake did not differ between controls and sesbania-supplemented goats. There was no difference among diets in total dry-matter intake, intake of cell wall constituents or digestibility. Average daily gain for control goats was – 1 g/day as compared with 21 g/day for supplemented goats.

The feeding of formaldehyde-treated soya-bean meal (F-SBM) as a supplement to either napier grass or napier grass–legume diets increased (P < 0·05) intake of dry matter and weight gain of goats. Napier grass intake of animals supplemented with only F-SBM was higher (P < 0·05) than that of control animals. The efficiency of N utilization from F-SBM was higher than that in the legumes, but replacement of legumes by F-SBM above 4% F-SBM feeding had no effect on weight gain or efficiency of utilization.

It was concluded that napier grass of 6–8 weeks' regrowth with 12% crude protein did not provide sufficient protein for growing goats owing to inefficient protein utilization. The increase in efficiency of protein utilization on supplemented diets is mainly associated with the larger proportion of water insoluble, rumen degradable protein and possibly acid-pepsin soluble protein in tropical tree legumes.

Agriculture can benefit substantially from long-range weather forecasts, for the month or the season, which can help to optimize farming operations and deal more effectively with the adverse impacts of climate variability, including extreme weather events. In the context of climate change, long-range weather forecasts also represent key elements for the development of adaptation strategies. In spite of an undeniable potential, long-range forecasts issued for instance by the European Centre for Medium-Range Weather Forecasts (ECMWF) have yet to find widespread application in European agriculture. To address partially the question of why this is the case, the performance of the ECMWF monthly ensemble forecasting system was examined. It was noted that predictability is currently limited to about 3 weeks for temperature and 2 weeks for precipitation and solar radiation. This may appear deceptive at first sight, but it was noticed that precipitation forecasts over a month are, overall, at least as valuable as information obtained from observed climatology. Encouraged by this finding, the possibility of using monthly forecasts to predict soil water availability was tested. In an operational context, this could serve as a basis for scheduling irrigation. Positive skills were found for lead times of up to 1 month. It was concluded that more systematic investigations of the possibilities offered by long-range forecasts should be undertaken in the future. However, this will require additional efforts to increase the quality of the forecasts, design appropriate application tools and promote the dissemination of the outcome within the agriculture community.

Findings from multi-year, multi-site field trial experiments measuring maize yield response to inoculation with the phosphorus-solubilizing fungus, Penicillium bilaiae Chalabuda are presented. The main objective was to evaluate representative data on crop response to the inoculant across a broad set of different soil, agronomic management and climate conditions. A statistical analysis of crop yield response and its variability was conducted to guide further implementation of a stratified trial and sampling plan. Field trials, analysed in the present study, were conducted across the major maize producing agricultural cropland of the United States (2005–11) comprising 92 small (with sampling replication) and 369 large (without replication) trials. The multi-plot design enabled both a determination of how sampling area affects the estimation of maize yield and yield variance and an estimation of the ability of inoculation with P. bilaiae to increase maize yield. Inoculation increased maize yield in 66 of the 92 small and 295 of the 369 large field trials (within the small plots, yield increased significantly at the 95% confidence level, by 0·17 ± 0·044 t/ha or 1·8%, while in the larger plots, yield increases were higher and less variable (i.e., 0·33 ± 0·026 t/ha or 3·5%). There was considerable inter-annual variability in maize yield response attributed to inoculation compared to the un-inoculated control, with yield increases varying from 0·7 ± 0·75 up to 3·7 ± 0·73%. No significant correlation between yield response and soil acidity (i.e., pH) was detected, and it appears that pH reduction (through organic acid or proton efflux) was unlikely to be the primary pathway for better phosphorus availability measured as increased yield. Seed treatment and granular or dribble band formulations of the inoculant were found to be equally effective. Inoculation was most effective at increasing maize yield in fields that had low or very low soil phosphorus status for both small and large plots. At higher levels of soil phosphorus, yield in the large plots increased more with inoculation than in the small plots, which could be explained by phosphorus fertilization histories for the different field locations, as well as transient (e.g., rainfall) and topographic effects.

The screening of rhizobacteria for growth promotion of sorghum (Sorghum bicolour (L.) Moench) was conducted under greenhouse conditions for a total of 78 bacteria isolated from the rhizosphere of sorghum in Ethiopia, and 86 isolates from the rhizosphere and rhizoplane of grasses in South Africa. Three isolates from Ethiopia, all identified as Bacillus cereus, enhanced growth promotion by resulting in statistically significant increases in at least five parameters. Of these, B. cereus (KBE7-8) resulted in significant increase in shoot and root biomass. Among effective isolates from South Africa, B. cereus (NAS4-3) and Stenotrophomonas maltophilia (KBS9-B) showed significant increases in all the parameters measured. The isolates which resulted in significant growth promotion colonized the roots effectively with a count up to ⩾108 cfu/g. In the study conducted to elucidate the possible modes of action by these effective isolates, indole 3-acetic acid-like substances were detected in culture filtrates of the isolates ranging from 4·2 μg/ml by Serratia marcescens (KBS9-R) to 22·8 μg/ml by B. cereus (KBS5-H) in the presence of 2 mg tryptophan/g nutrient broth solution. Higher rates of solubilization of tricalcium phosphate on Pikovskaya agar medium were shown by Chryseomonas luteola (KBS5-F), S. marcescens (KBS6-H) and B. cereus (KBE9-1). There is very limited knowledge of the use of rhizobacteria in agriculture in Ethiopia and South Africa. The current study therefore generates valuable information towards application of plant growth promoting rhizobacteria as alternatives to chemical fertilizers.

1. A gradually decreasing plane of light and increasing plane of darkness is not an essential factor for stimulating the onset of oestrus in sheep.

2. Sheep being short-day breeding animals, a standard and regularly maintained rhythm of short-light and long-dark will stimulate the onset of oestrus.

3. The terms short and long are used in the relative sense only, since their significance is solely a means of supplying the necessary contrast impulse to the pituitary gland.

4. A ratio of 1 part of light to 2 parts or more of dark is sufficient to supply the contrast effect.

5. Oestrous cycles induced by artificial light rhythms appear to be normal in all respects, con forming to the normal intervals between heat periods and associated with the ovulation of normal ova.

6. The anoestrous period varies in depth, and sheep which have just entered it may be brought back into oestrus very much faster than animals which are in deep anoestrum.

7. The milk yield of lactating ewes does not appear to be unduly depressed by the onset of oestrous periods induced by an artificial light-dark rhythm.

The structure, distribution and dimensions of skin strata and sweat glands have been investigated in Egyptian buffaloes and cattle. Samples from sixteen body regions were taken from three adult bulls of both species. Identical studies were also made on one buffalo calf and two buffalo embryos. Serial vertical and horizontal sections were cut from each body region using the ‘terpineol paraffin wax’ method. The following results were obtained.

1. Buffalo skin is characterized by dermal papillae enclosing papillomatous epidermis. The fibrous structure of the dermis is similar in both species. In buffaloes, the average thickness of skin, main epidermis, papillomatous epidermis, and cornium is 6·5 mm., 50, 115, and 11μ respectively. The epidermis coefficient is 12 for the main epidermis and 18 for the papillomatous epidermis. In cattle, the average thickness of skin, epidermis and cornium layer is 4·3 mm., 51 and 5 μ respectively, while the epidermis coefficient is 8.

2. The average number of hair follicles per sq.cm. of skin is 394 in the buffalo and 2633 in cattle. Each hair follicle is accompanied by two large lobulated sebaceous glands in the buffalo, and one small bilobed gland in cattle.

3. There is no species difference in the histology of the sweat glands. Each hair follicle is accompanied by one sweat gland in both species. In the buffalo, the body of the sweat gland is oval and convoluted, while the duct is twisted at its attachment to the body. In cattle, the body of the gland is elongated while the duct is straight. The number of sweat glands per sq.cm. of skin is 394 in the buffalo and 2633 in cattle. The dimensions of the sweat glands are larger in buffaloes than in cattle. The length, circumference and sweating surface of the gland is 0·58, 0·47, and 0·276 sq.mm. in the buffalo, and 0·47, 0·26, and 0·124 sq.mm. in cattle respectively. The glandular surface of sweat glands per sq.cm. of skin is 1·07 sq.cm. in the buffalo and 3·08 sq.cm. in cattle.

4. The type of sweat gland secretion is apocrine in both species. In the buffalo, successive stages of apocrine secretion are observed, and the merocrinelike form is rare. In cattle, the merocrine-like form prevails and the other stages are very rare. The theory (Findlay & Yang, 1950) of intraluminal transformation, of secretory products from coarse granularity to fluid homogeneity is supported. The effect of locality on the type of sweating activity is stressed.

5. There are species differences in the distribution of blood vessels and capillaries. In the subepidermal level, the arterial branches are more frequent and superficial in buffaloes than in cattle. Capillaries are found in the dermal papillae of buffalo skin. The capillary loops encircling the hair follicle are more frequent in cattle than in buffaloes. The blood capillaries supplying the sebaceous glands are more numerous in the buffalo than in cattle. The blood supply of sweat glands is poor in both species.

6. There are age differences in the skin histology. The number of hair follicles per sq.cm. of skin in a 5-months-old embryo, calf at birth, and adult buffaloes is 10560, 1248 and 400 respectively. There are no skin glands in the 1-month and 5-months-old embryos. The sweat gland in the calf is small in size and similar in structure to that of the adult. Calves have fewer sweat glands than adults.

7. The body conformation and the degree of pigmentation are affected by species, breed and locality.

8. The secreting activity of the sweat glands may be affected by the locality.

9. It seems that there are species differences in the mechanism of heat convection and radiation, insensible perspiration and sensible perspiration, due to histological differences.

1. The contents of moisture, total nitrogen and intramuscular fat (and its iodine number), and the ultimate pH, were determined on longissimus dorsi (lumbar and thoracic regions), psoas major, rectus femoris, triceps (lat. head), superficial and deep digital flexor, sartorius and extensor carpi radialis muscles from ten pigs, of accurately known history, in each of three weight groups—pork, bacon and manufacturing (150, 200 and 250 lb. live weight, respectively).

2. In addition, the myoglobin content of longissimus dorsi (lumbar), psoas major, rectus femoris, triceps (lat. head) and extensor carpi radialis was also determined. In all five muscles there was an increase in pigment content with increase of body weight, but there was some suggestion that the myoglobin content of psoas major and triceps showed a proportionally greater increment between pork and bacon weights and rectus femoris and extensor carpi radialis between bacon and manufacturing weights.

3. In pigs of all three weight groups there were highly significant differences in fat-free moisture content between muscles and between animals. The mean, fat-free moisture content of longissimus dorsi (lumbar) (76·33%) is significantly less than that of longissimus dorsi (thoracic) (76·94%) and the mean value in the latter is significantly less than that in all the muscles except psoas major (77·28%). The mean fat-free moisture content of deep digital flexor (80·00%) is significantly higher than that in all the other muscles studied. There is evidence for a direct, but not linear, relationship between the contents of fat-free moisture and connective tissue (as calculated from hydroxyproline concentration).

4. Differences in ultimate pH between animals and between muscles were highly significant; but not those between the three weight groups, although there was a tendency for higher values in the muscles from bacon and manufacturing groups.

5. Both for the data overall, and within a given muscle, there was a direct proportionality between ultimate pH and fat-free moisture content. Except in the case of deep digital flexor correlation coefficients between these two parameters were significant. These correlations varied in significance for different muscles between the three weight groups.

6. Overall, the mean total nitrogen content (fat-free) of longissimus dorsi (lumbar) (3·77%) was significantly greater than that of longissimus dorsi (thoracic) (3·69%) and the latter greater than that of psoas major (3·58%). Such differences were also apparent within each weight group. The values were significantly greater than those for the six other muscles studied. The overall mean fat-free nitrogen content of deep digital flexor (3·17%) was very significantly less than that for all the other muscles. For the muscles of pork, bacon and manufacturing weights, overall nitrogen contents (fat-free) were 3·38, 3·44 and 3·55%, respectively. There was a significant inverse correlation between nitrogen (fat-free) and moisture (fat-free) (r = –0·88).

7. The ranking of muscles with respect to their contents of intramuscular fat was significantly different between weight groups. In contrast to the bovine, there was no significant difference overall between the intramuscular fat contents of longissimus dorsi in lumbar and thoracic regions; and these were both significantly higher than levels in psoas major, although the converse is true in the bovine.

8. Variation in the intramuscular fat content of the lumbar region of longissimus dorsi was strongly reflected by those in longissimus dorsi (thoracic), psoas major, rectus femoris, triceps and superficial digital flexor; but little with those in extensor carpi radialis and deep digital flexor; and not at all with that in sartorius.

9. There was no significant difference overall in the iodine number of intramuscular fat between weight groups. Iodine numbers in both thoracic and lumbar regions of longissimus dorsi were significantly lower than those in all the other muscles studied. The overall correlations between intramuscular fat and its iodine numbers were r = –0·70, – 0·71 and – 0·66 in pigs of pork, bacon and manufacturing weights: each of these was significant.

10. In discussing the results, it is suggested that those circumstances causing a high ultimate pH in muscle (e.g. fatigue) may concomitantly effect redistribution of body water and hence explain the observed proportionality between water content and ultimate pH. Significant differences in moisture content between muscles may be related to their relative proportion of connective tissue or to its nature. On the basis of much of the chemical data obtained, the muscles studied appear to fall into three groups—longissimus dorsi (lumbar and thoracic), deep digital flexor, and the rest, although such a conclusion does not accord with that suggested by anatomical dissection. Aspects of the relative maturity of the muscles are considered.

Five inbred Large Whites from the same strain as used by McMeekan (1940) were reared on a High Plane of nutrition to approximately 330 lb. live weight at which one was killed as a control. The rest were put on to a submaintenance diet of straw and water and killed successively at roughly equal intervals in live weight between 330 and 200 lb. The weights of blood, organs and offals were determined and the carcasses were jointed and completely dissected into their constituent tissues. The total weights of each and the weights within the various joints were recorded.

(1) Organs. The early-maturing organs, brain, eyes, etc., continued to grow. Other organs like the heart, liver, lungs, etc., suffered a greater or less degree of atrophy which was probably determined by a suspension of their functions.

(2) Carcass composition. The tissues of the carcass were affected in reverse order to their development, i.e. fat most, muscle less and bone least. Bone continued to grow in the earlier stages of submaintenance.

The initiation of leaf and spikelet primordia was studied at sites ranging in latitude from Newton Abbot (50·6°N) to Aberdeen (57·2°N) in crops sown in the middle of September, October and November 1983. The rate of primordium initiation tended to decrease from south to north but there were also marked differences between quite close sites.

The rate of leaf initiation increased with temperature but photoperiod had little effect; the rate of spikelet initiation was affected both by temperature and by photoperiod. There were differences in the total number of leaves initiated which were only partlyexplained by differences in vernalization.

Expressing leaf and spikelet initiation rates in terms of thermal and photo-thermal time respectively showed a constant rate of leaf initiation and a constant and more rapid rate of spikelet initiation.

Carcass data for 424 castrated male lambs, comprising seven breed-type groups, were used toevaluate a series of linear measurements, subjective scores and the lean content of sample joints as predictors of percentage lean in carcass. The groups represented the main types of British lamb and mean carcass weights ranged from 12·8 kg (Welsh Mountain) to 20·8 kg (Lowland Longwool). Lambswere selected from commercial abattoirs to cover the ranges of fatness and conformation normally found in practice within each group. The pooled within-group S.D. for percentage lean was 3·70 and theoverall S.D. (ignoring groups) was 3·96.

Predictors were compared in terms of precision and the stability of their prediction equations. Of the characteristics measured on the intact carcass, subjective scoring of external fatness gave the most precise prediction both within groups and overall (R.S.D.within = 2·82, B.S.D.overall = 3·17). Fat thickness over the eye muscle (0) was the best predictor among those taken on the quartered carcass (R.S.D.within = 2·76, R.S.D.overall =3·00). The most precise individual predictors were percentage lean in the best end neck and shoulder joints (R.S.D.within = 1·51 and 1·59 respectively). Among pairs of predictors not involving dissection, the combination of C and percentage kidney knob and channel fat in the side gave the most precise prediction (R.S.D.within = 2.51, R.S.D.overall = 2·68). The stability of the prediction equations between groups tended to increase with the precision of the predictors. Among the more precise predictors, the equation for percentage lean in the leg was a notable exception, being particularly variable from one group to another.