Selected data of McMeekan (1940, 1941) were reanalysed to compare the proportions and distribution of tissues, and the weights of some organs, in pigs growing at different growth rates due to differing levels of nutrition. The effects of variation in fat content were excluded, and the distribution of tissues was compared at the same total weight for each tissue, by allometric regressions. Except for components of the head and neck, and the stomach, the results do not support a concept of retardation of development by poor nutrition of those parts of the body with the highest relative growth rates.

An experiment with two blocks containing phased sequences of continuous spring barley after beans or fallow was located on sandy soil over Lower Greensand on a gentle north to south (N–S) slope at Woburn Farm. Season had the greatest effect on yield with a 135% difference between the worst (1975, 1·73 t/ha) and the best (1974, 4·06 t/ha). years. N–S position was the next most important factor with average differences of 65 and 52% between the plots at the top and bottom of the site in blocks I and II respectively. The third most important factor was E–W position which gave a maximum difference of 35% in 1975.

A fertility trend with a strong linear component, which was most conspicuous in drier years, followed the main slope of the experiment and was attributed to erosion (fieldwash). After 1972 as different cropping sequences were progressively introduced, yield variation due to crop sequence differences was confounded with this positional effect.

Crops in the eastern block were taller by l·5–12·3% and, after adjustment for the linear trend, yield was on average 15·6% greater than in the western block. The site is astride a N–S soil boundary with Stackyard series to the east and Cottenham series to the west. The Stackyard soil has a greater available water capacity, and is subject to drought less frequently than the Cottenham soil. Using Penman's (1971) data for the Cottenham series at Woburn and estimates of profile available water for the two series elsewhere on the farm, theoretical yields were derived, which were generally greater than actual yields adjusted for the N–S linear trend (block means 1·47–4·32 t/ha), but which showed similar trends in the between-block differences. Explanations for discrepancies between theoretical and actual yields are discussed. The incidence and severity of take-all disease and differences in soil pH were always small and unlikely to have caused significant yield variations.

The course of free proline accumulation in leaves, stems, roots and ears was examined during the development of the wheat cultivars Yecora and Generoso grown in the field with or without irrigation. More negative values of leaf water potential were associated with higher amounts of free proline in the various organs. In most cases, proline accumulated more readily with increasing water stress before heading than after ear emergence in the leaves, stems and roots of both varieties. Differences between the two cultivars concerning the sensitivity of the mechanisms inducing proline accumulation to water stress existed mainly in the reproductive phase: Generoso accumulated proline more readily than Yecora. There is evidence that the increased amounts of free proline in Generoso can be associated with more effective dehydration and drought avoidance mechanisms.

An experiment has been made to study the effect of the pattern of distribution of a fixed amount of production compound on milk yield, milk composition and live-weight change in the first 20 weeks of lactation and any carry-over effects on performance in the remaining part. Adult British Friesian cows of predicted high yield potential were randomly allocated to a graded (G) or flat-rate (F) system of feeding.

There was no significant effect of treatment on milk yield, milk composition or yield of milk constituents in the experimental period or in the whole lactation.

Live-weight changes were not significantly different between treatments at any stage of lactation. Calculated energy balances showed losses until the 4th week of lactation. Thereafter positive balances occurred but it was not until the 9th week for treatment G and the 15th week for treatment F that the original zero balance was restored. The total balance was in good agreement with live-weight gain for treatment F but not for treatment G.

Calculated efficiencies of utilization of metabolizable energy for milk production (Klo) were variable throughout lactation and lower than the currently accepted standards.

Response of rice to root inoculation with Azospirillum under different N fertility levels was studied over three consecutive seasons under tropical conditions. The response to Azospirillum was more pronounced at lower levels (30 and 45 kg N/ha) of fertilizer N than at a higher level (60 kg N/ha). Although the root inoculation with Azospirillum resulted in a significant increase in mean yields of both grain and straw especially at low levels of N (30 and 45 kg N/ha), the interaction between the N fertilizer and inoculation was not statistically significant.

Changes in Cu concentration in the livers of adult Scottish Blackface (B), Welsh Mountain (W) and B × W ewes fed diets containing 4, 9, 17 and 29 mg Cu/kg D.M. were measured over a 28-week period. Measurement continued during two further periods of 18 weeks when first all sheep were fed the diet containing 4 mg Cu/kg D.M. and finally, when 4 mg Mo/kg D.M. was added to this diet.

During the first period the increase on all diets was least in B ewes and, apart from the 4 mg Cu/kg D.M. diet, greatest in W ewes; this difference increased as the Cu in the diet increased. The rate of increase for all ewes diminished towards the end of the period. All breed types retained proportionately less Cu in their livers as the Cu in the diet increased; at one extreme B ewes fed 17 or 29 mg Cu/kg D.M. retained equal amounts.

When during the second period all sheep were fed the 4 mg Cu/kg D.M. diet the Cu concentration in their livers decreased, the rate of decrease being greatest for ewes whose mean concentration in the liver was highest, but at similar concentrations the decrease was greater in B than W ewes. During the final period the decrease was faster and was again associated with the mean Cu concentration, but the decrease was not significantly affected by breed.

Throughout the trial, W ewes had the highest concentration of Cu in their plasma, whilst B ewes and ewes fed the 4 mg Cu/kg D.M. diet throughout had the lowest concentrations both in plasma and in their kidneys at slaughter.

The results show that breeds differ in their ability to retain Cu from the diet in their livers. The magnitude of these differences depends on the intake of Cu and Mo from the diet and is affected by the concentration of Cu in the liver. Breed differences in the absorption and endogenous loss of Cu are suggested.

Information is assembled on how much wheat yields vary from place to place, from year to year and between years in England and Wales. Some indication of the practical importance of this variation is given by comparisons with the yield differences caused by individual management decisions as measured in comparative experiments, and with plot-to-plot variation in such experiments.

Regression analysis was used to examine the relationship between the weight of water, protein and ash (kg) and fat-free empty body (FFEB) weight (kg) in data from six published and one unpublished experiment conducted in this laboratory. The analysis involved 201 sheep divided into 12 groups which were either in positive growth, weight stasis, weight loss or compensatory growth prior to slaughter. Each of the relationships between water, protein or ash and FFEB was linear and could be expressed by a common slope. Small (though statistically significant) differences in intercept were found between treatments. The following overall equations provide a simple description of the data:

water (kg) = 0·721 FFEB + 0·37, R.S.D. 0·18,

protein (kg) = 0·215 FFEB - 0·22, R.S.D. 0·16,

ash (kg) = 0·055 FFEB - 0·07, R.S.D. 0·09.

Published data for cattle were also examined and corresponding equations are:

water (kg) = 0·701 FFEB + 3·59, R.S.D. 2·6,

protein (kg) = 0·234 FFEB - 2·00, R.S.D. 2·3,

ash (kg) = 0·060 FFEB - 0·71, R.S.D. 1·8.

It is suggested that these equations could be used in computer simulation models of growth to calculate FFEB gain (or loss) from nitrogen balance.

The effects of treading and the return of excreta on a Lolium perenne-Trifolium repens sward defoliated by sheep set-stccked at high and low stocking rates were examined. Sward performance was measured inside ‘graze-through’ cages which allowed defoliation without treading and excreta return, and outside where sheep grazed either fitted with harness to prevent the return of excreta or unharnessed to allow the normal return of excreta. Live-weight gain was measured from excreta return and non-return swards. The treatments imposed had large effects on herbage growth and botanical composition.

At a stocking rate of 25 yearling wethers/ha, sheep excreted about 1·1 kg N/ha/day, which increased soil N and led to an increase in herbage growth of about 26 %. The return of excreta increased ryegrass tiller density and this was partly responsible for a 26% reduction in the proportion of clover in the sward; the weight of clover was 13% loss where excreta were returned, and on this treatment stolon length at the end of the experiment was similar to that at the beginning. Doubling the stocking rate increased the N returned via excreta to about 1·3 kg N/ha/day, and this increased herbage growth by 53% but suppressed the proportion of clover by 21%, though not the weight of clover. Clover stolon length decreased during the experiment at this stocking rate, both with and without the return of excreta. Sheep live-weight change benefited from the stimulus to herbage growth where excreta were returned at the high stocking rate, but not at the low stocking rate.

Treading by 25 sheep/ha increased soil compaction but had no significant (P > 0·05) overall effect on herbage growth and botanical composition. However, treading by double the number of grazing animals significantly reduced herbage growth by 10%, plant root weight by 47% and the proportion of clover in the sward by 11%.

Differences in sward performance between stocking rates were due more to the difference in defoliation intensity between these stocking rates than to either treading or the return of excreta.

Labelled fertilizer N (15N depleted ammonium sulphate) was used to investigate both soil and fertilizer N use by winter wheat established in contrasting seed beds, these being soil cultivated to 20 cm depth or left undisturbed. The crop's response to, and recovery of, a range of N levels from 0 to 280 kg/ha given as a divided application in spring, were measured over two seasons. It was found that during the first season the direct-drilled wheat took up, on average, more fertilizer N but less soil N than wheat in cultivated soil, probably through differences in organic-matter mineralization. The different cultivation systems produced similar grain yields at all rates of applied N; however, when no fertilizer N was given, dry-matter production and soil-N uptake by the crop in the undisturbed soil were substantially less than by the crop in the cultivated soil. Crop recovery of the fertilizer N at harvest was between 29 and 40% of that given. After harvest, an average of one third of the applied fertilizer N was found in the top 60 cm of the soil profile. In the following season on the same plots a second winter wheat crop, receiving no fertilizer N, was drilled. At harvest there was shown to be an increase in grain yield and soil- and fertilizer-N uptake at the higher srates of N given in the previous season. In spite of this the recovery of the labelled residues was small, no more than 6% of the original application, or 15% of the residues remaining in the soil, irrespective of cultivation system.

Left and right 9–10–11 rib joints from 104 Madura, Ongole, Bali, Grati (or Friesian cross) and buffalo bulls were dissected into bone, muscular and fatty tissues and then ground and chemically analysed for water, ash, ether extract and protein contents. The carcasses from 48 of these bulls were also ground and analysed for these same chemical components. Within-breed relationships between dissectible and chemical composition in the rib and between dissectible composition of the rib and chemical composition of the carcass were tested by regression analyses.

There were no breed differences in the relationships between bone and ash or between muscle and protein in the rib, but at the same content of rib fatty tissue, buffaloes had less predicted rib ether extract than Bali, Ongole or Madura cattle. At the same ash content of the rib, Madura bulls had the most carcass ash. Rib-muscle content was considered to be a poor predictor of carcass protein. At the same fat content of the rib, breed differences in predicted carcass ether extract were large with Grati having higher levels than Bali and all four cattle breeds having higher levels than buffaloes. Use of rib-fat or rib-energy contents to predict carcass energy yielded relative breed differences similar to those when rib fat was used to predict carcass ether extract.

Differences in the distribution of fat within the carcass, particularly in the subcutaneous fat depot, were considered to have a major bearing on differences in the within-breed relationships. Therefore, published part-whole prediction equations should be used with caution when comparing genotypes likely to differ in the distribution of tissue within the carcass.

Four bruchid-resistant and four susceptible cow-pea cultivars and their F2 crosses were evaluated for oviposition, egg hatching and emergence scores of cow-pea weevils, Callosobruchus maculatus Fabr.

Whereas oviposition and number of eggs hatched were normally distributed, percentage of eggs hatched was not. For percentage weevil emergence, the F2 progenies with susceptible parents as females had a different distribution from that of their reciprocals with resistant parents as females.

Preferential oviposition was not observed among the parents and their F2 progenies. Resistance was observed at the egg hatching and weevil emergence stages. Percentage of eggs hatched was significantly and positively associated with percentage weevil emergence.

For many horticultural crops the distribution of weight over size grades is of more importance than the total weight. This paper shows how simply determined features of interrelationships of the weight, size and shape of an individual in the crop can be combined to provide estimates of various aspects of the distribution of crop weight over size grades. The two relationships required are (i) the probability density function of the grading variable for the crop; (ii) a function relating the weight of an individual to the corresponding value of the grading variable.

The paper shows how each of these can be determined either from published data or by simple experiment. Examples using data on onions and carrots are given to illustrate this and also to show some of the more important practical applications of the methods. For example, they allow the results of grading with one set of size grades to be extrapolated to a different set of grades without recourse to further measurement or experimentation and this is illustrated using published data on carrots. Other possible uses are also discussed and outlined.

Indonesian Ongole and swamp buffalo bulls were fed ad libitum a diet of elephant grass (Pennisetum purpureum) with five levels of rice bran (0, 1·2, 2·4, 3·6 and 4·8 kg/head/ day) in a study lasting 161 days. Measurements were made of the digestibility of the diet, the balances of nitrogen, phosphorus, calcium and water and the metabolizability of the gross energy. Using multiple regressions, the daily intakes of metabolizable energy were partitioned between maintenance and growth.

Feeding rice bran stimulated appetite, initially improved feed conversion efficiency and increased growth rates. Each additional kilogram of rice bran fed depressed grass dry-matter intake by 0·8 kg in the buffaloes and 0·6 kg in Ongoles. Rice bran had little effect on digestibility of dry matter, organic matter and energy. Metabolizable energy contents of rice bran and elephant grass were calculated to be, respectively, 9·5 and 8·2 MJ/kg dry matter. Nitrogen and phosphorus status was improved in the supplemented animals but the balance of calcium was adversely affected. Voluntary feed intake was always higher in the buffaloes but the differences were reduced with increasing rice-bran supplementation.

Metabolizable energy requirements for maintenance and growth did not differ significantly between Ongole and buffaloes and were similar to values calculated for British animals.

A branching peduncle individual was observed in a population of cow pea Vigna unguiculata (L.) Walp. cv. Ife Brown. Normal plants have unbranched peduncles with flowers arranged in alternate pairs at distal ends of the peduncles. However, the mutant plant has branched peduncles with flowers arranged in pairs alternately along the branches as well as at the ends of the branches. The branches arise in the axils of stipulate trifoliate leaves which develop on the peduncles. The normal plant has between one and four pods per peduncle, whereas the mutant is capable of carrying between two and ten pods per peduncle. The branching trait is under genetic control, involving a single gene with the normal peduncle completely dominant over the mutant. Evidence for the genetic control and its possible usage is discussed. Data on some agronomic properties of the mutant are also presented.

Hydrolysis and sorption reaction of pyrophosphate (PP) in soils and uptake of PP by maize were studied using some acid soils from southern Nigeria. Rate of hydrolysis varied with the soil type, and half-lives of hydrolysis ranged from 10 to over 40 days in unsterilized soils and more than 40 days in all cases when the soils were sterilized. An appreciable fraction (over 40%) of the added PP resisted hydrolysis, the effect being more pronounced in the sterilized soils.

Sorption of both PP and orthophosphate (OP) by soils followed the Langmuir isotherm. The adsorption capacity and bonding energy index for all soils were greater for PP than for OP.

A short-term glasshouse experiment showed that PP was as good as OP as a source of P to maize. When the soils were limed to pH 6, PP appeared to be superior to OP.

Chlorophyll contents per unit leaf area and unit dry weight, chlorophyll a:b ratio, visual colour rating, specific leaf area, and leaf fresh weight: dry weight ratios were estimated for 12 couch (bermudagrass) varieties (Cynodon spp. L.) in winter (July) and spring (October). Net photosynthetic and dark respiration rates were estimated in winter only.

The chlorophyll contents per unit leaf area were higher in all varieties in spring than in winter, but per unit weight were more variable. The varieties differed substantially in the net photosynthetic and dark respiration rates. The specific leaf areas were greater in winter than in spring in five varieties: in others it changed little. The fresh: dry weight ratios of the leaves were almost constant between varieties in the spring but varied greatly during the winter. Visual colour ratings were well correlated with chlorophyll contents per unit area but not with weight. The net photosynthetic rate was closely correlated with chlorophyll content (per unit area) but not so closely with colour rating.

Indonesian Ongole and swamp buffalo bulls that had previously been given 0, 1·2, 2·4, 3·6 or 4·8 kg/head/day rice bran plus ad libitum elephant grass were slaughtered after 161 days feeding. Abdominal depot fat, full and empty reticulo-rumen and cold carcass weights were recorded. Various carcass variables were measured and the 9–10–11 rib joints were dissected into bone, muscle and fat. Carcass gross energy was calculated from rib-fat content using previously determined regression equations. Feed efficiency was expressed in terms of the ratios of live-weight gain or carcass-energy accretion to metabolizable energy available for growth.

Increasing supplementation with rice bran resulted in larger abdominal fat depots, higher dressing percentages, increased carcass fatness (and hence carcass gross energy) and improved rib muscle to bone ratios. Carcass conformation was unaffected by dietary treatment. When feed efficiency was expressed per unit live-weight gain, there was a decrease with increasing rice-bran feeding. Feed efficiency, expressed per unit of carcass energy accretion, improved with rice-bran supplementation and was generally higher in buffalo than in Ongole bulls. Dietary and species differences in feed efficiency could be primarily explained by the differential energy cost of deposition of, and the availability of energy from, carcass protein and lipid.

The effects of some plant growth regulators on the growth and development of two cultivars of oil-seed sunflower (cvs Flambeau and Luciole) were examined in 1977 and 1978. Sunflower is a marginal crop for the United Kingdom, being late maturing and susceptible to infection by grey mould (Botrytis cinerea) during the seed-filling period.

An experiment in 1977 indicated that suitable growth regulators might improve sunflower husbandry principally by shortening the stem, allowing late applications of fungicide and insuring against lodging. A mixture of mepiquat chloride and ethephon (BAS 098 OOW) was the most effective stem shortener. Daminozide gave variable effects on yield depending on the rate and time of treatment. The number of seeds per m2 was the major determinant of yield; 1000-seed weights and oil contents were similar for all treatments. The proportion of linoleic acid in the oil was very high in all experiments.

In 1978 a second experiment involving daminozide and two sunflower cultivars revealed seasonal and varietal differences in response. The timing of growth regulator application seemed critical to affect seed yield. The third experiment, in 1978, investigated the results of applying BAS 098 OOW to four plant population densities varying from 40000 plants/ha to 160000 plants/ha. High plant population density advanced maturation by 2 weeks, but in these plots the crop lodged in the absence of growth regulator treatment.

Herbage intake by grazing dairy cows can be estimated by measurements on the pasture ('t Mannetje, 1978) or by measurements on the animal (Raymond, 1969; Corbett, 1978). Of the sward sampling techniques, the difference method, based on pre- and post-grazing sampling, has the greatest potential for providing valid estimates of herbage intake, but only when grazing periods are short and stocking densities are relatively high (Pigden & Minson, 1969). Estimates of intake by measurements on the animal are made by the faecal output-indigestibility ratio technique (Raymond, 1969; Corbett, 1978). The most widely used marker for the determination of faecal output is chromic oxide (Cr2O3).