1. The typical profile of south-western Nigeria formed over acid igneous rocks under alternating conditions of percolation and evaporation is described. The profile being (a) brown sandy soil, (b) concretion layer, (c) red clay, (d) mottled red and white clay, (e) whitish clay, (f) rotting rock. Acidity increases with depth.

2. Analyses of the concretion layer show that it consists chiefly of silica (quartz), ferric oxide, and occasionally some manganese. Alumina does not occur to a large extent.

3. From studies of the mobility of the iron and soluble salts throughout the profile it is suggested that the profile is developed by a rise of an iron sol which is deposited on a layer of quartz to form the concretions.

4. The Yoruba name “Il***pa” has been adopted by the authors for describing such a profile.

1. In general the juvenile growth of interspecific Triticum and intergeneric Tritioum-Aegilops amphidiploids, was normal and did not deviate from the parental behaviour. However, in the case of the interspecific hexaploids derived from T. monococcum and T. aegilopoides there was an early check in growth, and all the amphidiploids derived from A. caudata developed more or less severe chlorosis.

2. Most amphidiploids were intermediate between their parents in mature plant characters. However, in the hexaploid Triticum interspecific amphidiploids there was a transgressive increase in plant height, and whilst the derivatives of Triticum x Aegilops crosses fell within the range of their parents, they were closer to one or other parent depending upon the Aegilops species involved.

3. The ear morphology of the Triticum interspecific amphidiploid was generally a composite of that of the parents, the influence of each parent being detectable. In the Triticum-Aegilops amphidiploids, however, ear morphology was so strongly influenced by the Aegilops species, that there was frequently no obvious difference between the ears of amphidiploids with a common Aegilops parent but different wheat parents.

4. The fertility of the amphidiploids was low and there was no significant correlation between the fertility of amphidiploids and parents. There was a significant correlation between both the grain weight, and number of spikelets per ear, in parents and amphidiploids, but whilst the mean grain weight was about that of the parent with the heavier grain, the mean of spikelets per ear was about that of the parent with the fewer spikelets.

Lactating red deer (Cervus elaphus) hinds and their calves were rotationally grazed on Lotus corniculatus or perennial ryegrass/white clover pasture at an allowance of 12 kg DM/hind/day during summer 1996 in Palmerston North, New Zealand. Half the hinds suckled pure red deer calves and half suckled hybrid (0·25 elk[ratio ]0·75 red deer) calves. Measurements were made of the diet selected, voluntary feed intake of the hinds and liveweight changes of the hinds and calves.

Lotus corniculatus and perennial ryegrass constituted c. 90% of green material in the diet selected on the respective forages. Total nitrogen (N) content and organic matter digestibility (OMD) were higher for Lotus corniculatus than for perennial ryegrass/white clover pasture. Lotus corniculatus contained 21 g condensed tannin (CT)/kg dry matter (DM), whilst pasture contained only traces of CT (1·6 g/kg DM).

Hinds grazing Lotus corniculatus tended to have higher voluntary feed intake, and calf liveweight gain (485 v. 399 g/day) and weaning weight (52·6 v. 48·1 kg) were greater than for deer grazing perennial ryegrass/white clover pasture. Hybrid calves grew faster than pure red deer calves (P<0·01), with hybrid calves grazing lotus having very high liveweight gain (c. 520 g/day). Liveweight gain of hinds grazing Lotus corniculatus also tended to be higher (91 v. 20 g/day) than for hinds grazing perennial ryegrass/white clover pasture. CT was bound more strongly during chewing by red deer than had been found in comparable studies with sheep and the nutritional significance of this is discussed. Nutritional reasons for the superior performance of deer grazing Lotus corniculatus are discussed.

Four bruchid-susceptible and four bruchid-resistant cow-pea cultivars were crossed to produce 16 F1s and their reciprocals. From each cross, six generations, P1, P2, F1, F2, BC1, BC2, were obtained. Each cross was fitted to the additive-dominance model. Estimates of additive and dominance variances were obtained from the half and full sib analyses of the F1s and their reciprocals respectively. It was demonstrated that resistance to cow-pea weevils has additive, dominance and maternal components.

Barley plants were grown at low, high, increasing and decreasing densities in an attempt to manipulate the environment. The effects on tiller production and development were measured.

Increasing density with time had less effect than decreasing it. Tiller number was the most plastic character, tiller production being earlier in those plants which emerged into low density, being delayed or inhibited in other treatments. The number of spikelets/ear and the length of the inflorescence were found to be less stable characters than the stage of ear development. Percentage spikelet survival showed a downward trend, with increasing density stress.

Blood and liver samples were taken from four fasted pregnant and five fasted non-pregnant Finnish Landrace × Dorset Horn ewes. The following metabolites were measured: adenine monophosphate (AMP), adenine diphosphate (ADP), adenine triphosphate (ATP), citrate, 2-oxoglutarate, phosphoenolpyruvate, pyruvate, lactate, 2-phosphoglycerate, 3-phosphoglycerate, α-glycerophosphate, malate, β-hydroxybutyrate, acetoacetate, glutamate, alanine and NAD+.

The effects of a 6-day fast on non-pregnant ewes were shown as significant reductions in the hepatic concentrations of 2-phosphoglycerate, alanine, NAD+ and ADP, together with significant increases in the hepatic concentrations of 3-hydroxybutyrate, malate and the ratio of 3-hydroxybutyrate:acetoacetate. In the blood there were significant reductions in the concentrations of urea, citrate and in the ratio of 3-hydroxybutyrate: acetoacetate.

Similar but more marked changes occurred in the late pregnant ewes, with additional significant reductions in the hepatic concentrations of citrate, ATP and the level of cell energy, and additional increases in the blood of the ratio of lactate: pyruvate and the concentrations of 3-hydroxybutyrate and 2-oxoglutarate. However, unlike the non-pregnant ewes no significant changes in either the plasma concentration of urea or the hepatic concentration of ADP were observed in the late pregnant ewes.

Crops of potatoes grown on 0·2–0·3 ha in each of the years 1971–8 at Stockbridge House Experimental Horticulture Station achieved total tuber yields of 70–94 t/ha. Yield was determined by the period and rate of tuber growth. The observed period of growth varied from 96 to 132 days and the rate from 0·55 to 0·90 t/ha/day. Rate of growth had the greater influence on variability of yield between the years. The number of tubers produced per unit area had little influence on their total weight, but had marked effect on their size. Adequate water supply was essential for very high yields. Experiments indicated that current recommendations for potash fertilizer can be adequate but that nitrogen and phosphate fertilizer use may need to be enhanced for very high yields. For high yields, the number of seeds planted per hectare may need to be higher than normally recommended in order to avoid the production of large tubers unsuitable for the ware market.

(1) Nine Scottish Blackface and four Merino × Cheviot ewes were shorn and given an acute cold exposure (at approximately −18 °C) in climate chambers. Individual exposures lasted up to 10 h. Because they were shorn, the sheep subsequently received 4 weeks of mild cold exposure, although kept indoors at an ambient temperature between + 8 °C and +15 °C. Skin and wool samples were taken before and after treatment. Twelve unshorn control ewes were also sampled.

(2) Wool production in the Blackface sheep was depressed following the treatment, and this was accounted for by a reduction in both the mean length and the mean diameter of the wool fibres.

Ruminants have extremely low concentrations of polyunsaturated acids in their adipose tissue as a result of hydrogenation of dietary lipids by microbes in the rumen. The possible association between intake of ruminant products high in ‘saturated’ lipids and the incidence of atherosclerosis in man has stimulated research on procedures for altering the fatty acid composition of ruminant tissue lipids. Vegetable oils, emulsified with a protein, spray-dried, and treated with formaldehyde, have been found to be protected from hydrolysis and hydrogenation in the rumen (Cook et al. 1970; Scott, Cook & Mills, 1971). Their subsequent digestion in the small intestine, and absorption of the fatty acids by the animal, results in tissue lipids high in linoleic acid (Faichney et al. 1972; Faichney, Scott & Cook, 1973; Cook et al. 1972; Garrett et al. 1976).

The chewing behaviour of red deer (Cervus elaphus) during eating and the effectiveness of chewing on feed comminution was studied in two experiments. In Expt 1, deer were fed long or chopped lucerne (Medicago sativa) hay, and feed intake and chewing activity were recorded. In Expt 2, the rumen was emptied and test meals of fresh chicory (Cichorium intybus cv. Puna), lotus (Lotus corniculatus cv. Grasslands Goldie), ryegrass (Lolium perenne cv. Ruanui) forage and long lucerne hay were given, chewing activity recorded and the ingested forage quantitatively removed from the rumen. In Expt 1, the chopped hay was eaten more quickly than long hay (11·4 v. 8·3 g dry matter/min), and required fewer chewing bites per g dry matter eaten. In Expt 2, the four forages were consumed at similar rates (mean 4·3 g organic matter/min) and there was no significant difference in the chewing required to consume either total organic matter (OM) or cell wall OM. Deer chewed more quickly when eating lucerne hay than when eating lotus, and it was estimated that a greater number of chewing bites were required to form a bolus of lucerne hay than to form a lotus bolus. The proportion of ingested OM which was comminuted so as to pass a 1 mm sieve (efficiency of chewing) was greater for lotus (0·485) and lucerne hay (0·.518) than for chicory (0·.267). The efficiency of chewing ryegrass (0·.366) was intermediate and not significantly different from any other forage. For all forages, the main effect of chewing during eating appeared to be the release of cell contents, rather than the comminution of cell wall. Physical breakdown to particles which passed a 1 mm screen but were retained on an 0·25 mm screen was low for fresh forages (0·074–0·086) but was slightly higher for lucerne hay (0·127). Deer reduced feed particle size during eating with a similar efficiency to sheep, but were less efficient than goats.

It is suggested that the chewing effort associated with forage consumption by red deer is related to the need to form a bolus. The amount of chewing may be as much influenced by the physical characteristics of the forage (e.g. leaf size and shape) as by its chemical composition, and the extent of comminution during eating may be determined by the processing needed to form a bolus and the resistance of the feed to bolus formation.

Demand for milk has waxed and waned over the last 100 years in response to changing perceptions of its health effects. Milk consumption was promoted for health benefits in the first half of the twentieth century, whilst milk fat has increasingly been regarded as something to avoid over the last 30 years. Emerging research is showing that milk fat provides a number of important components, almost uniquely, within a balanced human diet. Understanding of the role of animal diets in controlling milk fat content and milk fatty acid profiles has grown over this period. The multiple correlated changes associated with milk fat depression have led to a number of mechanistic theories which have not been resolved completely. The detailed mechanisms at the molecular level remain to be elucidated. Interestingly, the two research areas of milk fat content and milk fatty acid profiles have merged as it became clear that some of the intermediates of rumen biohydrogenation are involved in regulating milk fat content. The multivariate nature of milk fatty acid profiles means that future studies must make use of multivariate statistical techniques. These approaches will also be of great value in assessing the consequences of fatty acids for human health, where studies of the effects of single nutrients can be misleading. Issues about the sustainability of the marine harvests mean that attention needs to focus on alternative sources to meet the growing demand for n-3 fatty acids, notably from forages. Whilst attention has focused on milk fatty acids for their effects on human health, future work should also address effects on health and reproductive function of cows offered diets designed to alter milk fatty acid profiles.

The results obtained for dry matter and energy digestibility with 116 different rations fed to 242 non-pregnant dry cows and 96 laotating cows were studied.

With winter rations, dry-matter digestibility (Y) is linearly related to dry-matter intake (X1) and to the crude fibre content of the dry matter (X2):

Y = 89·58–0·557X1–0·863X2.

A similar equation was obtained for energy digestibility (Y):

Y = 90·68–0·195X1–0·892X2,

where X1 represents the energy intake (in 1000 kcal) and X2 the crude-fibre content.

Digestible dry matter or energy can be estimated very accurately from dry matter or energy intake and from crude-fibre content.

There is a highly significant linear relation between dry matter or energy digestibility and nitrogen concentration of the faeces, especially with grass.

Dry-matter digestibility is also influenced by the physical form of the feeds and by individual factors.

A method of assessing colour of grass leaves was developed to distinguish between cultivars. Leaves from a representative population of 60 plants of each cultivar were measured. To eliminate subjective judgment a colour difference meter was used, giving tristimulus values X, Y and Z (approximating to red, green and blue respectively), from which the colour co-ordinates L, a and b of the Commission Internationale de L'Eclairage system were calculated.

In a pilot study two visually distinguishable perennial ryegrass cultivars were easily separated (P <0·01) using the colour measurements. In a further examination comparing 23 cultivars, 68% of all possible cultivar pairs were separated (P <0·01).

The effects of green manuring with Sesbania aculeata, or with Leucaena leucocephala leaves and of weed incorporation on the physical properties of a clay loam soil under a rice–wheat rotation were compared at New Delhi, India, in 1986–87. Under puddled conditions, the volumetric moisture content of the saturated topsoils varied from 0·400 cm3/cm3 in the Sesbania-treated plots to 0·425 cm3/cm3 in plots receiving no green manure, but in the unsaturated soils at rice harvest the corresponding values were 0·317 and 0·271 cm3/cm3. The effects of the green manures on the water content of the soils were still evident after a subsequent wheat crop. Other soil physical properties affected by the treatments were the following (data refer to topsoils measured after the rice harvest): settling index (cm/cm), an estimate of structural instability, which ranged from 25·5% (Sesbania-treated plots), to 28·6% (weed incorporation), 29·7% (Leucaena-treated plots) and to 33·5% (NPK-fertilizer only). Soil dispersion increased from 6·0 to 10·0 g/100g through the same treatment sequence. Hydraulic conductivity in the NPK-fertilizer only plots was 31 cm/day, but increased to 4·8 cm/day in the Sesbania-trealed plots. Sesbania was superior to the other green manures for improving soil physical properties after its incorporation.

The nitrogenous composition of the water soluble, non-protein nitrogen fractions of three samples of high-pH-spoilt silage and one sample of overheated silage were examined in detail. The amino acid nitrogen content of the high-pH-spoilt silages declined with increasing extent of spoilage, due to a selective degradation of the amino acids. Losses of amino acids were associated with proportionate increases in the amount of volatile basic nitrogen. Lower aliphatic amines were not present and it was therefore concluded that the ultimate end product of nitrogen metabolism in high-pH-spoilt silages was ammonia. Only low concentrations of putrefaction products, such as putroscine, cadaverine and histamine were present.

The composition of the non-protein nitrogen fraction of the overheated silage was unusual in that the ammonia nitrogen content was high and associated with the complete destruction of certain amino acids. The free amino acid nitrogen content was low but this was partially compensated for by a very high ‘peptide’ nitrogen content. There was no evidence of putrefaction products in this silage.

Starting with the F2 generation of the single-cross commercial hybrid Lorena (PR3183), recombinant lines were developed combining half-sib/S1 evaluation on widely spaced plants in the direction of high yielding per se. Combining ability tests consisted of crosses between: (a) recombinant lines of common pedigree and (b) recombinant lines and freely available inbred lines. The highest-yielding crosses between recombinant lines reached 100% of the original F1 hybrid in a percentage of 14·2. Low heterosis was estimated owing to additive gene action of recombinant lines. Crosses between recombinant lines and freely available inbred lines outyielded significantly the commercial F1 hybrid in a percentage of 33·3. Heterosis was greater and the original F1 hybrid was outyielded significantly because of non-additive gene action. When the applied breeding procedure on a source population with high yield adaptability is adopted and where effects of intergenotypic competition masking the inherent genotypic value are controlled, population improvement may be substituted by combined half-sib/S1 selection for productivity of lines per se in low stress conditions during the very early stages.

Maize in Canada is grown mainly in the south-eastern part of the country. No comprehensive studies on Canadian maize yield levels have been done so far to analyse the barriers of obtaining optimal yields associated with cultivar, environmental stress and agronomic management practices. The objective of the current study was to use a modelling approach to analyse the gaps between actual and potential (determined by cultivar, solar radiation and temperature without any other stresses) maize yields in Eastern Canada. The CSM–CERES–Maize model in DSSAT v4·6 was calibrated and evaluated with measured data of seven cultivars under different nitrogen (N) rates across four sites. The model was then used to simulate grain yield levels defined as: yield potential (YP), water-limited (YW, rainfed), and water- and N-limited yields with N rates 80 kg/ha (YW, N-80N) and 160 kg/ha (YW, N-160N). The options were assessed to further increase grain yield by analysing the yield gaps related to water and N deficiencies. The CSM–CERES–Maize model simulated the grain yields in the experiments well with normalized root-mean-squared errors <0·20. The model was able to capture yield variations associated with varying N rates, cultivar, soil type and inter-annual climate variability. The seven calibrated cultivars used in the experiments were divided into three grades according to their simulated YP: low, medium and high. The simulation results for the 30-year period from 1981 to 2010 showed that the average YP was 15 000 kg/ha for cultivars with high yield potential. The YP is generally about 6000 kg/ha greater than the actual yield (YA) at each experimental site in Eastern Canada. Two-thirds of this gap between YP and YA is probably associated with water stress, as a gap of approximately 4000 kg/ha between the YW and the YP was simulated. This gap may be reduced through crop management, such as introducing irrigation to improve the distribution of available water during the growing season. The simulated yields indicated a gap of about 3000 and 1000 kg/ha between YW and YW,N-80N for cultivars with high YP and low YP, respectively. The gap between YW and YW,N-160N decreased to <2000 kg/ha for high Yp cultivars with little difference for the low Yp cultivars. The different yield gaps among cultivars suggest that cultivars with high YP require high N rates but cultivars with low YP may need only low N rates.

Of 41 male kids, 14 were killed immediately after birth (3·3 kg BW); the remainder were either fed on goat milk to satiation or weaned at 10 kg BW. After achieving 15·7 kg BW, weaned kids were fed on complete diets including either 20 or 40% straw. Milk-fed kids were slaughtered at 16·8 or 26·7 kg BW, weaned kids at 15·7 or 29–30 kg BW, respectively (at least four kids per treatment). Empty BW as a proportion of final live BW was 0·91±0·02 in milk-fed kids compared to 0·85±0·04 and 0·76±0·04 in kids given complete feeds including 20 or 40% straw, respectively. Empty BW of kids in the heaviest groups were c. 24 kg for milk-fed or weaned kids. Energy and crude protein contents per kg empty BW increased from 4·5 MJ and 158 g in newborn kids to 12·2 MJ and 163 g in milk-fed kids or 10·4 MJ and 194 g in weaned kids, respectively. No influence of the feeding system was found on mineral contents of empty BW. Ca, P and K remained constant at 12·6, 7·7 and 1·9 g/kg, Mg increased from 0·32 to 0·46 g/kg and Na decreased from 2·0 to 1·3 g/kg. Differences in composition of live BW gain are mainly caused by differences in gut-fill. Efficiency of utilization of ME for growth was c. 0·75 in milk-fed kids even at high BW, but only 0·31 in weaned kids. Proportions retained of dietary N, Ca, P, Mg, Na and K were highest in milk-fed kids between birth and 16·8 kg BW: 0·57, 0·88, 0·78, 0·40, 0·37 and 0·10, respectively. They were lowest in kids fed on complete feed including 40% straw from 15·7 to 30·3 kg BW: 0·25, 0·26, 0·32, 0·04, 0·11 and 0·04, respectively. Weaning seems to be of greater influence on composition of BW gain and efficiency of utilization than the increase in empty BW.

Experiments were conducted to determine the effect of lime pre-treatment on the chemical composition and in vitro rumen degradability of date palm leaves (DPL). Lime pre-treatments, with or without oxygen supply, were applied for 1, 2 and 3 weeks at 25 and 40 °C. Lime was neutralized by the Calcium-Capturing-by-Carbonation process. Delignification and in vitro rumen gas production were significantly influenced by duration, temperature and oxygen. At 40 °C, oxygen presence stimulated more delignification and subsequently increased in vitro rumen degradability. Lime pre-treatment with 0·2 g calcium hydroxide (Ca(OH)2)/g dry biomass for 3 weeks at 40 °C in the presence of oxygen resulted in a 3-fold increase in gas production after 24 h of incubation, compared with untreated biomass. Lime treatment of DPL with aeration resulted in higher lignin removal and subsequent rumen degradability than without aeration. A techno-economic analysis is needed to select the most efficient and economically feasible pre-treatment procedure.