A balance experiment was carried out using four young lactating goats in a Latin square design, fed with perennial ryegrass (Lolium perenne) from plots that had received 377 kg K/ha (diet 1); 63 kg K plus 377 kg Na/ha (diet 2); 188 kg K plus 188 kg Na/ha (diet 3) or no fertilizer (control diet 4).

The apparent availability of Mg was high in all the grass diets (0·355–0·469); it was significantly depressed (P < 0·05) when the intake of K was high (diet 1); but was not significantly different when a high intake of K was accompanied by a high intake of Na (diet 3).

There was a significantly lower (P < 0·05) apparent availability of Na in diet 4 and a significantly higher (P < 0·05) apparent availability of K in diet 3. There were no significant differences in the apparent availability of Ca.

The plasma Mg concentration was not significantly affected by any dietary treatment but did decrease temporarily when diets were changed.

There were no significant effects on mineral concentrations in the milk.

Phenological development and its variation during reproductive growth have important effects on the yield and quality of forage grasses. In perennial ryegrass (Lolium perenne L.) genetic variation in heading date is well recognized, but there are no reliable studies about the variability in the length of the stem elongation phase. To determine the variation in phenological traits of single plants of perennial ryegrass genotypes, a field trial was conducted over three growing seasons (2011–2013) using plant material from eight different ecotype populations, sampled from old permanent grassland swards in Northern Germany. In addition to the phenological stages of jointing, heading and flowering, the critical phase of stem elongation was considered as a new phenological trait. It was hypothesized that the length of the critical phase between jointing and heading differs significantly among genotypes and thus offers a new tool for selecting for specific purposes, e.g. adaption to changing climatic conditions, cutting or grazing as well as yield and quality. The study revealed significant genotypic variation in the observed traits, which was highest for the critical phase (GCV = 0·21). Moderate heritability in jointing (h2 = 0·72) revealed a large environmental impact. In contrast, high heritability (h2 > 0·86) in heading, flowering and the critical phase imply a strong genetic effect. Moderate to high genotypic and phenotypic coefficients of correlation revealed a substantial linkage among the phenological traits. Results are discussed in the context of providing different approaches and strategies in forage crop production, especially with regard to regional weather conditions and future climate change. Significant differences among the tested ecotype populations indicate that existing diversity in permanent grassland can provide source material for further progress in grass breeding.

1. Two experiments involving length measurements of ninety-six bacon-pig carcasses showed that chopping out the backbones, chilling and laying the carcasses down on a table, each resulted in a decrease in average length. There was variation from carcass to carcass in the magnitude of these decreases which, in the case of the chopping out the backbone and laying down stages, was related to the fatness of the carcass, greater decreases being found in the longer, leaner carcasses than in the shorter, fatter sides.

2. Estimates of the precision of measuring showed that length from the junction of the first rib and the sternum to the symphysis pubis taken on hanging carcasses was less susceptible to errors than the same measurement taken on the lying carcass, and that both these measurements were more accurate than that from the atlas bone to the symphysis pubis taken on carcasses either hanging or lying.

This study aims to determine the effects of dietary crude protein (CP) content of early-weaned calves; and the influence of flint maize processing methods on intake, total tract nutrient digestibilities and performance of Nellore heifer calves. Fifteen early-weaned Nellore female calves (4 ± 0.5 months; 108 ± 13.1 kg) were used. In phase 1, animals were fed one of the following diets for 112 days: 130, 145 or 160 g CP/kg dry matter (DM). In phase 2, animals received one of the two diets for 84 days: 0.60 dry ground maize grain, 0.30 whole-plant maize silage plus 0.10 mineral-protein supplement or 0.90 snaplage plus 0.10 mineral-protein supplement. In phase 1, intake and digestibility of dietary components were not affected (P > 0.05) by increasing dietary CP content. Daily total urinary nitrogen (N) and urinary urea N increased (P < 0.05) in response to increasing dietary CP content. Animal performance was not affected (P > 0.05) by dietary CP content. In phase 2, maize processing methods did not affect (P > 0.05) intake and digestibility of dietary components as well as animal performance, carcase characteristics and carcase composition. Therefore, based on the current experimental condition, we conclude that dietary CP concentrations of 130 g/kg DM can be indicated for early-weaned Nellore calves. However, more studies are recommended to validate this result and to evaluate concentrations below 130 g CP/kg DM for early-weaned Nellore calves. Moreover, snaplage could be used as an exclusive fibre and energy source for finishing cattle in feedlot.

To identify separate effects of gender, castration and exogenous oestrogen on growth, castrated lambs of both sexes and entire male lambs (n = 8) were implanted subcutaneously with three sizes of oestradiol-17β implants, or not implanted, and grazed on ryegrass and white clover pasture for 180 days. A group of non-implanted entire female lambs (n = 8) was run together with the others. Non-implanted entire male lambs grew faster, had heavier heads, less internal, non-carcass fat and more protein and less fat and water in the carcass than non-implanted entire females. In addition, they had higher 12th vertebral spine, thicker tibia, and heavier and larger humerus than entire female lambs. Castration of male lambs reduced live-weight gain, weight of head and content of protein in the carcass whereas it increased carcass fat content. In addition, it caused lengthening of cannon bones and reduced height of 12th vertebral spine and length of tibia. In females, gonadectomy increased height of 12th vertebral spine and diameter to length ratio of the radius. Oestradiol treatment increased live-weight gain, reduced total internal and carcass fat, and increased water and protein content of the carcass in gonadectomized animals of either sex, and increased weight of carcass and head in spayed ewe lambs. Oestradiol treatment inhibited longitudinal growth of cannon bones and stimulated that of vertebral column and ribs, but had little effect on the dimensions of limb bones apart from increasing their diameter. Oestradiol treatment had no effect on muscle length but increased muscle girth and weight, except for m. splenius in ram lambs where muscle weight was reduced. Effects of oestradiol on skeletal measurements in most cases were linearly related to dose of oestradiol. It was concluded that the variable effects of sex steroids on the skeleton were related to the differential pattern of skeletal maturation. In early maturing bones acceleration of the growth process by an exogenous sex steroid caused elongation to cease prematurely, whereas in late-maturing bones the acceleration effect on elongation did not result in premature cessation. This observation may explain the often contradictory reports in the literature on the effects of sex steroids on linear growth of bone.

Observations on the onset of the breeding season in a flock ofSouthdown ewes in subtropical Australia (latitude 27° S.) indicated that the mean date of onset during the years 1962-65 was 3 March, with annual means ranging from 11 February to 17 March. There was evidence that, under some circumstances, ovarian activity may be initiated before the summer solstice.

The onset of the breeding season was later in ewe lambs than in yearling and adult ewes and the mean age at puberty was 239 days.

1. Two series of experiments designed to investigate the effects of delaying planting potato seed tubers after drawing ridges in preparation for planting and of consolidation of soil beneath seed tubers on the growth and yield of potatoes are described and the results discussed.

2. Delayed planting reduced the yield of saleable ware-size (> I¾ in.) tubers in one year by as much as 1.7 + 0.59 tons/acre, but had little effect in the other years, and it is argued that the effect was dependent on the tilth obtained in preparation for planting, the soil moisture content at the time the ridges were drawn, the amount of moisture lost during the delay period, and the rainfall after planting.

The relative uptake of phosphate, introduced as radioactive 32P into an Agrostis-Festuca hill land association in mid-Wales, was examined under two contrasting methods of cultivation: (i) complete cultivation, (ii) slot-seeding. Seedling plants of Lolium perenne S. 23 and Trifolium repens S. 184 were grown as pure stands and as binary mixtures with plants either 4 or 6 cm apart.

Relative uptake of phosphate was higher under complete cultivation and, in the binary mixtures, clover accounted for 26% of the uptake only. The percentage of phosphate removed by each of the species when grown in mixtures remained constant over cultivation treatments. The significance of the results to agronomic practice is discussed.

Experiments are described in which the relative importance of head storage capacity and carbohydrate supply was examined in five sorghum varieties of different heights. The varieties were: Namatera (270 cm), Dobbs (180 cm), MUS 78 (100 cm), MUS 23 (85 cm) and MUS 70 (85 cm). Techniques used were (i) cutting off part of the head or part of the leaf at anthesis, (ii) shading during different periods of development, and (iii) thinning the plants at different physiological stages. Varietal differences ranged from a situation where the head was little more than half-filled by the available carbohydrate (MUS 78), through intermediate stages (Dobbs and Namatera), to a situation where the head capacity limited the amount of carbohydrate which could be stored (MUS 23 and MUS 70). Some differences could be attributed to pre-anthesis competition between head and stem, but in the dwarfs a more important factor appeared to be pre-anthesis competition between head and leaf. It is suggested that for maximum efficiency of grain-yield production, maximum carbohydrate should be utilized for pre-anthesis head and leaf growth and that partitioning between these plant parts should be such that the supply of carbohydrate for grain filling is in balance with head storage capacity.

1. Two profiles of a drift soil at Craibstone, Aberdeenshire, have been examined in the field and in the laboratory. Both profiles have been derived from parent material of the same geological origin—a somewhat gravelly drift consisting of the granitic and metamorphic rocks of the district. One of the profiles was taken in uncultivated land and the other from arable land in the same area.

2. The chief results obtained in the present investigation may be summarised as follows:

Soil surface moisture is a dominant factor influencing the establishment of surface sown seed, but its measurement is difficult. A cobalt chloride (CoCl2) saturated paper strip (20×5 mm) technique was developed as a cheap but sensitive indicator of soil surface moisture. The influence of soil surface moisture on the seedling survival of three oversown legume species, subterranean clover (Trifolium subterraneum L. cv. Karridale), strawberry clover (T.fragiferum L. cv. Grasslands Onward) and Caucasian clover (T. ambiguum Bieb. cv. Monaro) was investigated in a glasshouse and a field experiment at Palmerston North, New Zealand, between 1 October and 30 November 1993. Intact sods were sprayed with glyphosate, placed in plastic trays (420×300×50 mm) and transferred to the glasshouse or field. Three soil surface moisture treatments were imposed in the glasshouse. In the field trial, the plastic trays were buried flush with the soil surface in contact with the subsoil and exposed to natural wind and rainfall. Bare seed was oversown in a 20 × 20 mm grid and then pushed into the soil with a roller studded with metal rods to simulate treading by sheep. The low soil surface moisture treatment and the field trial had the lowest seedling survival. The main cause for this was low surface moisture caused by wind, which hindered radicle entry into the soil. Subterranean clover was less susceptible to low surface moisture and had better net seedling survival in all the treatments than the other two legume species.

Experiments were conducted during 1992/93 and 1993/94 to determine the effect of different planting dates and dinocap applications on control of powdery mildew and yields of early and late maturing coriander cultivars. Early plantings resulted in lower overall disease severity values for both the cultivars, but the late maturing cultivar S-33 benefited more than RD-44, an early maturing cultivar. Early planting resulted in smaller increases in yield in RD-44 but provided considerable economic gains in S-33. Further, it was possible to achieve similar levels of control of powdery mildew and yields in coriander with fewer dinocap applications by early plantings of both the cultivars. Therefore, to reduce the fungicide inputs, it is important that emphasis should be placed on early plantings for managing powdery mildew especially in environments conducive for its development.

1. A method is described whereby absolute changes in the organic and mineral constituents of cacao leaves during decomposition may be followed.

2. On a basis of their behaviour during decomposition, the components measured fall naturally into three groups. The first group comprises lignin, total protein, resistant protein, dilute-acid protein, concentrated-acid protein and nitrate-nitrogen; these exhibit an absolute increase during decompositión. The second group, represented by hemicelluloses, cellulose and pentosans, all show a downward trend, the decrease being most rapid at the outset. Alcohol- and ether-soluble substances constitute the third group and are characterized by a very rapid decrease during the first few weeks of decomposition.

3. A large amount of material soluble in dilute acid which is neither protein nor reducing sugar is not accounted for; this on a carbon basis constitutes over 50% of the dilute acid hydrolysable fraction. The trend of this fraction is somewhat similar to the carbohydrate fractions. It is pointed out that this fraction should not be neglected in a proximate analysis of decomposing organic matter.

4. Potassium exhibits a very rapid decrease at the onset of decomposition, and the trend is closely parallel to the alcohol- and ether-soluble substances. At times of heavy leaf fall there is consequently a marked manurial effect which may amount to the equivalent of 1 cwt. of sulphate of potash per acre.

An analysis of the data from the continuous manurial experiment in Woodlands Field, Craibstone Experimental Farm, Aberdeen, has demonstrated the effects of fertilizers and of rainfall on the yields of various crops grown on a six-course rotation plan with a basal application of dung to the roots. The soil is a dark brown medium loam of which the parent material is ‘drift’ from the grinding down of granite and metamorphic rocks and is typical of a large class of glacial soils in the north-east of Scotland.

Of the three major nutrients nitrogen gave the largest mean response on every crop except hay. The hay yield was benefited least by nitrogen and most by potash. The effect of nitrogen was to depress slightly, but not significantly, the total production of the ley for the 3 years. Potash, on the other hand, significantly improved the yield of hay as well as of the aftermath and the following ‘pastures’. The phosphate and potash responses were approximately equal in respect of barley, oats and potatoes. Turnips, swedes and potatoes responded similarly to potash, but in terms of dry matter the response was markedly higher for potatoes.

Superphosphate proved more effective than ground mineral phosphate on every crop except turnips. Further study of the data revealed interesting differences between the crops in respect of their capacity for utilizing ground mineral phosphate. Oats gave negligible responses to mineral phosphate throughout the experiment.

Three trials were conducted over two cropping seasons, on portions of the production fields of the Nigerian Sugar Company sugar-cane estate, Bacita, to evaluate the efficacy of several herbicide mixtures for weed control in sugar cane using the varieties Co. 957 and Co. 1001. With a broad spectrum of weeds, early post-emergence applications of diuron + hexazinone (2·0 + 0·7 kg a.i./ha) followed by hexazinone + paraquat (0·5 + 0·3 kg a.i./ha) about 8 weeks after the first application gave satisfactory weed control that resulted in high cane yields. Addition of glyphosate to the mixture for the first application or its substitution for paraquat in the second application, or both, resulted in increased suppression of nutsedge. This was, however, more phytotoxic to the sugar-cane plants. Addition of pendimethalin to either diuron or hexazinone improved the control of grass weeds. Hexazinone-based mixtures were found to give longer-lasting weed control than the diuron-based mixtures. Both diuron and hexazinone were generally more selective on Co. 957 than on Co. 1001. The degree of weed infestation between 6 and 12 weeks after planting was inversely related to cane yield.

Chamber sampling is a common method for measuring nitrous oxide (N2O) emissions from agricultural soils. However, for grazed pastures, the patchy nature of urine deposition results in very high levels of spatial variability in N2O emissions. In the present study, the behaviour of the sample mean was examined by simulating a large number (9999) of random N2O chamber samples under different assumptions regarding the underlying N2O distribution. Using sample sizes of up to 100 chambers, the Central Limit Theorem did not apply. The distribution of the sample mean was always right-skewed with a standard deviation varying between 12·5 and 135% of the true mean. However, the arithmetic mean was an unbiased estimator and the mean of the sample mean distribution was close to the true mean of the simulated N2O distribution. The properties of the sample mean distribution (variance, skewness) were affected significantly by the assumed distribution of the emission factor, but not by distribution of the urine patch concentration. The geometric mean was also investigated as a potential alternative estimator. However, although its distribution had lower variance, it was also biased. Two methods for bias correcting the mean were investigated. These methods reduced the bias, but at the cost of increasing the variance. Neither of the bias-corrected estimators were consistently better than the arithmetic mean in terms of skewness and variance. To improve the estimation of N2O emissions from a grazed pasture using chambers, techniques need to be developed to identify urine patch and non-urine patch areas before sampling.

Sixteen cultivars of beans (Vicia faba L.) were evaluated in a triple lattice experiment over 2 years. Differences among and within minor and equina groups were significant for most of the measured traits. In general, among equina and minor groups, the variability of means for yield components was higher than the variability for seed yield per plant. Most European cultivars were lower in yield potential and in number of branches per plant, taller and later in maturity than North African cultivars.

Significant positive correlations were found for seed yield per plant with weight of pods per plant and with number of pods per plant. These results indicate their value for improvement by indirect selection for seed yield. On the other hand, significant positive correlations were also obtained between number of seeds per pod and pod length and between number of seeds per pod and 100-seed weight. The correlation coefficients for height and number of days to maturity with seed yield per plant were negative but insignificant. Other correlation coefficients were also insignificant and low in magnitude.

Trials were conducted during the summer seasons (1978 and 1979) at the Faculty of Agriculture, Elminia University, to evaluate the effect of some growth regulators on sex expression, sex ratio and yield production of snake cucumber. The results obtained showed that both sex expression and ratio could be modified with plant regulator sprays even under the long and high temperature conditions of Elminia governorate. All plant regulators induced the formation of the first female flower at lower nodes compared with the control. There was significant suppression of male flowers in plants sprayed with plant regulators. All the treatments gave an increase in total yield and improved fruit characters.

Comparisons were made of the tuber yield and leaf morphology of three dihaploids, their chromosome-doubled derivatives and tetraploid parthenogenetic parents grown in a glasshouse at low, medium and high fertilizer levels. Differences in yield between the dihaploids and doubled dihaploids were not significant (P > 0·05) and responses to increases in fertilizer were similar. Leaf complexity showed generally large (usually significant, P< 0·05) increases when the fertilizer level was increased from medium to high. For the heterozygous tetraploid parents the tuber yield increased more than leaf complexity. Probably the dihaploids and doubled dihaploids utilized the additional fertilizer to increase foliage growth rather than tuber yield whereas the converse was the case for the tetraploid parents. There was no evidence that chromosome doubling resulted in changes in the response of dihaploid genotypes to changes in the fertilizer level.

An experiment combining a hyperinsulinaemic euglycaemic clamp approach and an isotope dilution method determined the effects of cold exposure and time relative to feeding on blood glucose metabolism in four sheep. The sheep, fed 20 g/kg body-weight (BW) of lucerne hay cubes and 5 g/kg BW of maize-based concentrates once daily, were exposed in turn to a thermoneutral environment (20 °C) and a cold environment (0 °C) for 20 days. The combined experiments were performed at four different times relative to feeding, i.e. 3 to 2 h, 2 to 1 h and 1 to 0 h before, and 1 to 2 h after the initiation of feeding for the basal periods, and 1 to 0 h before, and 0 to 1 h, 1 to 2 h and 3 to 4 h after the initiation of feeding for the glucose clamp periods in both environments. [U-13C]Glucose was continuously infused for 6 h after a priming injection. Insulin was continuously infused at 6·0 mU/kg BW per min for 2 h, which corresponded to the last 2 h of the [U-13C]glucose infusion. Blood glucose concentrations were maintained euglycaemic during the insulin infusion by concomitant variable glucose infusion. Blood glucose turnover rate (GTR) during the basal period was enhanced by cold exposure (P=0·01) and feeding (P=0·04). Blood GTR increased (P<0·01) with the glucose clamp. During the glucose clamp, blood GTR and glucose infusion rate (GIR) were greater (P=0·003 and P=0·001, respectively) during cold exposure than in the thermoneutral environment. Time relative to feeding influenced (P=0·003) the GIR, whereas changes in blood GTR and endogenous glucose production rate were not significant. No significant cold×feeding interaction was observed in these variables. It was suggested that, in sheep, glucose metabolism was enhanced by cold exposure and the glucose clamp. It was probable that blood glucose metabolism during the glucose clamp was influenced by cold exposure and feeding, but the combined effect of cold exposure and feeding was not significant.