Two varieties of oil-seed rape were drilled in 1979–81 at a range of seed rates. Percentage establishment, plant weight, height, and the ratio of seed to total aboveground dry matter were lower in high-density plots. Seed yields were not increased when the seed rate was raised from 9·0 to 13·5 kg/ha (Expts 1 and 2) or from 4·5 to 18·0 kg/ha (Expt 3) owing to a compensating reduction in the number of pods per plant. Seed quality and 1000-seed weight were not influenced by the seed-rate treatments.

The development of the maxillary teeth in cattle was studied by recording eruption into the oral cavity and by radiographic examination following bisection of the skull. Observations of second molar intra-oral eruption showed that varying stages were seen at different ages. Radiography of the teeth allowed determination of the degree of crown and tooth development in the permanent premolar and molar teeth as well as stages of temporary premolar tooth resorption. Radiographic inspection showed that in the same animal all the permanent maxillary cheek teeth except the first premolar were less well developed than their mandibular counterparts. It was suggested that the intra-oral eruption of the second maxillary molar and radiography of the maxillary teeth provided a better method of age estimation in cattle than the traditional one of examining the intra-oral eruption of the incisor and canine teeth.

Experiments were conducted in association with farmers during 1977, 1978 and 1979 on a River Estate sandy loam at Valsayn and on a Cunupia clay loam at Piarco, Trinidad, to assess the relative importance of components in a set of practices for wetseason production of ‘yellow shell’ pods of ‘blackeye’ type of cow pea (Vigna unguiculata (L.) Walp.). Though the response of the cow pea growth, yield and seed quality characteristics were similar at both locations, crop performance was consistently better at Valsayn and was attributed to more favourable soil conditions and to a lower incidence of pests (mainly Ceratoma beetles), cow pea severe mosaic virus, and weeds. Overall, it was found that pest control was the most important management factor, accounting for a mean yield increase of 144%. The adoption of the improved cultivar, California Blackeye No. 5, increased yield by 77%. Other inputs resulting in significant yield increases were, in order of magnitude, weed control (40%), roguing of mosaic infected plants (37%) and high plant density of 110000 plants/ha (23%). A fertilizer treatment did not significantly increase yield. The results suggest that adoption of the insect control treatment by farmers in their cultivation of an improved cultivar sown at high plant density, the use of herbicide and roguing of mosaic infected plants have practical potential and would be economically justified for the production of high yields and good quality ‘yellow shell’ pods of vegetable cow pea for processing.

Five agricultural by-products, maize stover and cobs, wheat straw, grape marc and sunflower husks, were treated with alkaline reagents under various conditions.

Maize stover and wheat straw reacted quickly with both sodium hydroxide applied at a level of 4 g NaOH/100 g dry residue and a mixture of calcium and sodium hydroxides (1:1), which led to changes in chemical composition and increases in digestibility. However, ensilage of the treated product at about 37% dry matter (D.M.) was not successful.

When dried grape marc was treated with sodium hydroxide (4·3 g NaOH/100 g dry residue) apparent lignin content increased, although other changes in composition and digestibility were similar to the above. Nevertheless, digestibility remained low. Moreover, when previously ground marc was treated in the same way lignin and cellulose fractions increased markedly while digestibility decreased.

Treatment of maize cobs with increasing amounts of sodium hydroxide (2·1–4·2 g/100 g dry residue) at 80% D.M. gave progressively more favourable results, although no improvement in digestibility was noted when half the sodium hydroxide was replaced by calcium hydroxide. Similar positive results were obtained under industrial conditions at application rates of 3·2 and 4·5 g sodium hydroxide per 100 g dry residue. Pelleting the product led to a further increase in digestibility.

Sunflower husks also showed a decrease in hemicellulose content and increases in digestibility and volatile acid content after treatment with 4·4 g NaOH/100 g dry residvie under industrial conditions. Lignin content was unchanged. The pelleted products (about 80% D.M.) were stable for more than 6 months when stored in paper sacks.

Except with grape marc loss of hemicellulose provided a general indication of the success of alkali treatment, although correlation with increased digestibility did not reach statistical significance (r = 0·34). Volatile acid production and alterations in lignin content were not suitable as general indicators.

In general, alkali treatment of the examined materials improved digestibility, although the products with a high water content were subject to undesirable fermentative changes during storage and therefore should be used within a few days.

A re-examination of the results from 374 sheep used in previovis studies of calcium metabolism show there is a highly significant linear relationship between endogenous faecal loss of Oa and food intake, endogenous loss increasing by about 0·64 mg/day/kg body weight for each 1 g/day/kg body weight increase in food intake. This loss was unaltered by Ca intake or by pregnancy and lactation but was slightly higher in young animals than in adult animals given the same Ca intake on a body-weight basis. It is suggested that a variable factor for endogenous Ca loss, based upon some measure of level of feeding, should be introduced into rationing schemes.

A survey on 17 beef suckler herds in the north-east of Scotland showed that there was no relationship between herd serum copper concentration (range 0·16–0·92 μg/ml) measured within 1 month of mating and the conception rate of the herd calculated from the pattern of calving to that mating. Cows treated with 100 mg copper before mating, in trials on four farms with low copper status and involving 221 animals, did not have an improved conception rate compared with control animals on the same farm. Copper per sewould therefore not appear to be a major factor in determining the fertility of beef suckler herds.

Herbage from a grass-white clover sward was dried in the field to the hay stage (< 0·3 g moisture/g dry matter) at four times of year in 2 years comparing, in each case, all combinations of three stages of maturity, three levels of applied nitrogen and three thicknesses of swath; 35, 55 and 75 days' regrowth, 0, 75 and 150 kg N/ha and, on average, 220, 474 and 728 g herbage dry matter/m2 were compared.

The least mature herbage had the highest moisture content at the time of cutting and dried most quickly at a given swath thickness, being slightly drier than the more mature herbage at the hay stage. At the cuts in late May-early June and late Juneearly July, when the crop was predominantly grass, the application of nitrogen increased both the moisture content at the time of cutting and the initial rate of drying at a given swatli thickness, so that in the middle and later stages of drying there was no effect of applied N on moisture content. At the cuts in early and late August, herbage from the plots that had received no applied N, which contained a substantial amount of white clover, had the highest moisture content at the time of cutting, dried fastest at a given swath thickness and had the lowest moisture content in the later stages of drying. In the very early stages of drying, herbage in a thin swath lost water much faster than herbage in a thick swath, but subsequently the rate of drying was consistently faster in a thick than in a thin swath so that, by the hay stage, herbage in a tick swath was at least as dry as herbage in a thin swath. There was almost no interaction between the different types, of treatment.

Rain during the drying period had little or no effect on the nitrogen content of the crop, but reduced digestibility by about 9 units. Stage of maturity and swath thickness did not affect the extent of this reduction in digestibility.

Three experiments examined the effects on seedling emergence and seedling weight of covering pelleted, natural and pre-germinated seeds of the variety Pennlake with soil and other media.

Covering seeds with a peat-vermiculite mix gave significantly greater, earlier and more uniform emergence and seedlings with a lower coefficient of variation (c.v.) of weight than covering with soil.

Seedlings from pre-germinated seeds emerged more rapidly than those from natural and pelleted seeds and tended to be heavier when harvested 24 or 41 days after emergence. However, natural seeds consistently gave more uniform emergence than the other seed treatments and the lowest c.v. of seedling weight.

Twenty-eight centres participated in two co-ordinated trials to obtain further evidence on responses of growing pigs (20–86 kg) to different levels of copper sulphate (CuSO4. 5H2O) supplementation, and on effect of lowering the amount of copper in the ‘finishing’ diet. The levels of copper supplied were 141, 232 and 276 mg Cu/kg diet in the ‘starting’ diet in trial 1 and 125, 200 and 250 in the ‘starting’ diets continuing or reducing to 125 mg Cu/kg diet in the ‘finishing’ diets in trial 2. The results varied to such an extent that no definite conclusion could be drawn, but there was a tendency to support rather than dispute the accumulated evidence in world literature that the most effective levels of copper supplementation are from 200 to 250 mg/kg diet throughout the growing period.

The present study was carried out on adult fleeces, of Merino, coarse wool Barki and five of their crosses, of known birthcoats. The adult fleece traits studied were clean fleece weight, mean fibre diameter and its variability and mean staple length and its variability.

Birthcoat-adult fleece relationship was dependent on the breed studied. In Barki, plateau array in the birthcoat developed to adult fleeces with higher values of mean fibre diameter and its variability, mean staple length and clean fleece weight than those with saddle array. In ⅝ Merino there was a gradient in staple length, running from plateau, via saddle, to ravine, with higher values of the coarser arrays. Differences occurred in variability of fibre diameter between plateau and saddle arrays in ⅜ and ⅝ Merino and between saddle and ravine in ½, ⅝ and ¾ Merino.

Differences occurred where birthcoats, with plateau array with precipice, in the curly-tip group, grew into adult fleeces with longer mean staple than those with transition in Barki sheep. In the other breed groups differences observed in saddle array, with different features, precipice or transition, at the birthcoat level, did not contribute differences in their adult fleeces.

Selection of Barki lambs with plateau fibre type array in their birthcoats would result in higher clean adult fleece weights that have coarser fibre diameter, with higher variability, and longer staple than those with saddle array. Within saddle array, selection of those with reduced SK% would develop into adult fleeces with higher clean fleece weight and those with reduced CT% would grow into adult fleeces with finer diameter.

Selection of lambs that have birthcoat ravine array in f, ⅜, ½, ⅝ and ¾ Merino would reduce the within-staple variability in their adult fleece fibre diameter.

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.

Forty-five normal lactating buffaloes from Punjab Agricultural University, Dairy Farm herd, were used for this study and were divided into three groups as group I (control), group II (showers) and group III (wallowing). The study was conducted from May to September in two periods, May–June as period I (hot and dry) and July–September as period II (hot and humid). Potassium concentration was estimated on a flame photometer. The overall average values (m-equiv/l) were found to be lowest in the control group (21·5 ± 1·27) and highest in wallowing (24·3 ± 1·20). Lower values were obtained in period I than in period II. Different correlations of potassium concentration in red blood corpuscles with climatic variables are discussed. Erythrocyte potassium concentration may act as an index of heat tolerance in buffaloes.

The benefits to establishment and growth of white clover cvs Aberystwyth S.184 and Grasslands Huia of inoculation with three strains of Rhizobium trifolii, using the peat or liquid inoculum techniques, were investigated during 1975–8 on improved hill soils ranging from brown earth through dry and wet peaty podzol to deep peat.

Inoculation induced positive response in either number of seedlings, plant cover or dry-matter production in 18 out of 139 comparisons, had no effect in 118 and produced a negative response in three. Most of the positive responses to inoculation were at sites with wet peaty podzol or deep peat soils but of the five sites where increase in clover D.M. production was found in the first harvest year one was a brown earth. The positive agronomic responses occurred only when the proportion of plants with nodules was high and where a substantial proportion ( > 50%) of the latter contained introduced Rhizobium strains at least in the year of sowing. The three negative responses were in numbers of seedlings on one brown earth and two dry peaty podzol soils and with the Huia cultivar only. Despite lack of statistical significance at individual sites the dominant overall trend was for inoculation to enhance seedling establishment and the early growtli of white clover in all soil types.

On one brown earth and one dry peaty podzol soil there was some evidence that spraying the Rhizobium on to emerging white clover seedlings was more beneficial, atleast in microbiological terms, than the customary peat inoculum procedure.

The incorporation of even a small amount of nitrogen (30 kg/ha) into the seed bed at the time of sowing adversely affected germination, establishment and growth of white clover in some soils. Sometimes the effects of this nitrogen persisted into the first harvest year.

The design and analysis of an experiment to compare the yield of wheat grown continuously with that of wheat grown in two phases of a four-course rotation is described and the results discussed. A method of analysis which avoids making assumptions about the covariance structure of the errors derived from repeated observations on the same plots, which could be appropriate to other sorts of rotation experiments, is given.

There were no differences between yields of the first and second wheat crops which followed oats after beans in a four-course rotation, but the average of these two crops was 0·75 t/ha greater than the yield of wheat grown continuously. The response to N was the same in the two systems of cropping. The only yield component affected by the system of cropping was grain mass.

The performance of Welsh Mountain ewes and their single Clun-cross lambs on swards of perennial ryegrass (Lolium perenne L.), cocksfoot (Dactylis glomerata L.), tall fescue (Festuca arundinacea Schreb.) and timothy (Phleum pratense L.) was studied over 3 years (1975–1977) at a site 305 m O.D. in mid-Wales. Under a rotational grazing regime at a fixed stocking rate of 25 ewes and lambs/ha, mean daily lamb live-weight gain over the 84 days experimental period from early May to late July was 24 g higher on timothy than on perennial ryegrass and tall fescue and 35 g higher than on cocksfoot. Averaged for the 3 years the mean daily lamb live-weight gains were 194, 170, 170 and 159 g on timothy, perennial ryegrass, tall fescue and cocksfoot respectively. There were, however, marked interactions with years.

Ewe live-weight change varied considerably between grasses and years with cocksfoot poorer than timothy and perennial ryegrass. Mean ewe live-weight change ranged from an overall loss of 39 g/day in 1975 to a gain of 34 g/day in 1977.

Differences detected in animal performance between the four grass species altered during the 84 days of the experiment. Timothy and to a lesser extent tall fescue produced better animal performance early in the season whereas perennial ryegrass came into prominence during July.

The results are discussed in relation to the present and potential use of the grass species under upland conditions.

A series of measurements of the heat production of 16 adult sheep made at intervals of not less than 4 weeks when they were given precise amounts of different diets at about the maintenance level of nutrition were analysed statistically. The total number of observations was 365. For some sheep the observations spanned periods of more than 3 years and none spanned less than 1½ years.

There were no time-related trends in the metabolizability of the gross energy of the diet. It was found that the measured heat productions, the heat productions corrected to zero energy retention and the heat productions corrected to zero feed intake (calculated fasting metabolism) were sinusoidal with time. The amplitude of the sine coefficient was about 14% of the mean value, and in some sheep there was in addition a linear secular trend. The phase of the sine function was such that minimal metabolism occurred in midwinter and maximal metabolism in midsummer.

The results suggest that the seasonal variation in voluntary feed intake is associated with a similar seasonal variation in basal metabolic rate. The fact that all animals were given maintenance rations throughout further suggests that the higher metabolism is not due to higher feed intake.

Experiments with spring barley at Saxmundham, in each year from 1975 to 1978, compared two varieties (Julia v Wing), two amounts of granular N-fertilizer (50 v 100kg N/ha) and two times of applying it (seed bed v top-dressing), a liquid N-fertilizer spray (0 v 50 kg N/ha), mildew fungicides (with and without) and a rust fungicide (with and without), in factorial combination (26).

Leaf diseases were assessed and grain weighed and analysed for % N each year. Thousand-grain weights were measured in 1977 and 1978.

Yields were small in 1975 and 1976 because little rain fell in summer, but larger in 1977 and 1978, years with average rainfall.

Mildew was most severe in 1975 and least in 1978, brown rust most severe in 1975 and 1978 and practically absent in 1976. Granular N-fertilizer was best applied to the seed bed in all years, whether or not leaf diseases were controlled. Late sprays of liquid N-fertilizer increased yield less than equivalent amounts of seed-bed N, but increased % N in grain more. However, because they also decreased grain size, less of the N applied as a liquid was recovered by grain than was recovered from granules given earlier. The mildew fungicides increased yields by ca. 0·25 t/ha in 1975 and 1977, but decreased them in 1976. They had little or no effect on % N in grain, but increased grain size in 1977. The rust fungicide, benodanil, increased grain yields each year and especially in 1978 (0·37 t/ha). It had no effect on grain % N, but consistently increased grain size and so enhanced grain yield and N uptake.

Field experiments on crop compatibility and spatial arrangements in sorghum were conducted at the Indian Agricultural Research Institute, New Delhi in irrigated conditions in 1976 and 1978. Grain yield of sorghum increased when grown in association with the legumes greengram, groundnut, grain and fodder cow peas and soya bean, compared with sole sorghum. Planting of sorghum in paired rows (30:90 cm) with two rows of intercrop in the 90 cm space produced maximum yields of sorghum and intercrops.

The effect of implantation of trenbolone acetate and oestradiol into lambs soon after birth on the metabolism of alanine in the presence and absence of propionate has been studied in isolated perfused livers obtained from suckling and from ruminating lambs. The effect of butyrate on the metabolism of alanine in the presence and absence of propionate has been studied in livers obtained from the steroid implanted lambs.

Glucose production in the presence of alanine by livers from non-implanted suckling lambs was more than 3 times greater than that by livers from non-implanted ruminating lambs. Steroid implantation did not affect alanine uptake by the livers but metabolism within the livers was altered. Significant interactions were observed between the age of the lambs and whether or not they had been implanted with steroids for the rates of net glucose production in the absence of propionate (P < 0·01) and for the rates of release of urea by the livers in the presence of (P < 0·05) and absence of propionate (P < 0–01).

Propionate did not affect alanine uptake by livers obtained from either suckling or ruminating lambs, but there was a significant interaction (P < 0·05) between the age of the lambs and whether or not butyrate was infused, indicating that butyrate depressed alanine uptake by livers obtained from implanted ruminating lambs perfused in the absence of propionate. Despite this depression of alanine uptake the rates of net glucose production and urea production were unchanged, indicating that butyrate modified the metabolism of alanine in the livers of implanted ruminating lambs in that a greater proportion of the alanine carbon taken up must have been converted to glucose. Butyrate stimulated net glucose production in the presence of propionate and alanine in livers from suckling (P < 0·05) but not ruminating lambs. Butyrate was ketogenic and the release of 3-hydroxybutyrate accounted for 45 and 30% of the carbon taken up as butyrate by livers from suckling and ruminating lambs respectively perfused in the absence of propionate. Propionate was antiketogenic. Propionate inhibited urea formation from alanine by livers from implanted suckling (P < 0·05) and implanted ruminating (P < 0·001) lambs. This effect was diminished by the presence of butyrate. Lactate was released in the presence of propionate and accounted for approximately 12–5% of the carbon taken up as propionate.

It may be concluded that implantation of lambs with anabolic steroids maintains hepatic gluconeogenesis from alanine at rates more closely resembling those found in younger suckling lambs. The effects of the volatile fatty acids on alanine metabolism are likely to be of physiological significance when sheep are fed diets which result in a markedly altered pattern of rumen fermentation.

Herbage characteristics of perennial ryegrass (Lolium perenne L.), cocksfoot (Dactylis glomerata L.), tall fescue (Festuca arundinacea Schreb.) and timothy (Phleum pratense L.) pastures were obtained whilst rotationally grazed by ewes and their single lambs at a fixed stocking rate of 25/ha on an upland site (305 m O.D.) in mid-Wales. Drymatter production of cocksfoot averaged 32·1 kg/ha/day over the 3-year duration of the trial (1975·7) and was 13·3 kg/ha/day lower than that of the other three grass species. This resulted in a 8 kg/ha/day reduction in dry-matter intake on cocksfoot; this was significantly lower (P < 0·05) than that achieved on the other grasses, which were similar to one another around 36 kg/ha/day.

In vitro digestibility of the herbage ranked in the order perennial ryegrass > timothy = cocksfoot > tall fescue. Intake of digestible organic matter (DOMI) was lower on cocksfoot than on perennial ryegrass and timothy. Differences were also detected in crude protein, water-soluble carbohydrates and sodium composition between species.

Dry-matter intake was positively correlated with herbage growth rates (r = 0·95, P < 0·001) but not to digestibility of herbage on offer (r = 0·18). Both ewe and lamb live-weight gains were positively related to intake of dry matter and DOMI.

Reference is made to comparative yield data between the grasses obtained under cutting trials. In the 2nd and 3rd harvest years (1967–1967) growth rates in the grazing experiment were 76, 61, 81 and 80% of the 66·2, 66·7, 67·8 and 65·0 kg D.M./ha/day obtained under a cutting regime on perennial ryegrass, cocksfoot, tall fescue and timothy swards respectively. This illustrates the danger involved in assessing the potential of grasses based on such information.

The results are discussed in relation to the value of the species for use under grazing in the uplands.