Normal, self and backcross families in a triple test cross were used to investigate the inheritance of number of days from sowing to flowering and dry plant weight for a population of pure-breeding lines of bread wheat (Triticum aestivum L.). Several tests of non-allelic interaction, additive genetic and dominance variances were made that involved triple test cross and single tester analyses. Non-allelic interaction was found to be a component of the genetic variation for both traits. The additive and dominance variances were prevalent for both traits. Alternative estimates of additive genetic and dominance variance components did not differ significantly when tested by a weighted least-squares model fitting procedure. The results are discussed in relation to genetic improvement of bread wheat.

Two steers (Bos indicus and Bos indicus x Bos taurus) were acclimatized to an ambient temperature of 30 °C before working at this temperature on two treadmills (gradients 0 and 6°) for 2 h (one on each treadmill) whilst carrying a load equivalent to 10% of body weight. The study was then repeated at an ambient temperature of 15 °C. The effect of variation between animals, ambient temperature and rate of energy expenditure were tested on the linear regression model EEw = A PHR + B (where EEw is the energy expenditure (w/kg0·75) and PHR is the percentage increase of working heart rate over resting heart rate).

Animal and ambient temperature had no significant effect on the model. The gradient of the regression line was significantly greater (P < 0·01) when the animals were expending energy at the higher rate (about 30 W/kg live weight0·75) than when they were expending energy at the lower rate (about 14 W/kg live weight0·75).

Adrenaline was infused at three rates, 40, 15 or 3 μ/kg/h, in normal sheep and in sheep rendered hypercortisolaemic by infusion of cortisol at 150 μg/kg/h. In both normal and hypercortisolaemic animals, plasma concentrations of glucose and free fatty acids were increased by adrenaline treatment; plasma phosphate decreased with all treatments; plasma magnesium and potassium decreased on infusion of adrenaline at 40 or 15, but not at 3 μg/kg/h; plasma calcium decreased only on infusion of adrenaline in hypercortisolaemic animals, and plasma sodium concentration was unaffected by treatment.

Induction of a degree of lipolysis likely to occur in the field was not associated with a marked decrease in plasma magnesium.

To quantify changes in rates of metabolism and nutrient uptake of gravid uteiine, foetal and utero-placental tissues throughout gestation, mature Hereford cows received surgery at 132 ± 0·6 (n = 12), 176 ± 0·5 (n = 8), 220 ±0·4 (n = 11) and 245 ±1·5 (n = 7) days after mating. Indwelling catheters were implanted into a uterine artery and vein of all cows. Foetal catheters also were implanted into an umbilical vein and foetal femoral artery and vein (days 176 and 220) or into a placental artery and two placental veins (days 132 and 245). Approximately 5 days after surgery, deuterium oxide was infused into a foetal femoral venous or placental venous catheter during a 3 h period to quantify uterine and umbilical blood flows by steady-state diffusion methods. Oxygen, glucose, lactate and α-amino acid nitrogen concentrations were determined for uterine and foetal blood samples collected during this procedure.

Uterine blood flow increased 4·5-fold (2·92–13·181/min) and umbilical blood flow increased 21-fold (0·28–5·861–min) during the interval of gestation studied. The relative rate of increase of umbilical blood flow was about twice as great as that of uterine blood flow. Uterine arterial and umbilical venous concentrations as well as uterine arterial-venous and umbilical venous-arterial concentration differences in metabolites changed little with stage of gestation. However, because rates of blood flow increased, uptakes of O2, glucose and α-amino N by the gravid uterus and foetus increased as gestation advanced. The proportion of gravid uterine uptakes utilized by the foetus increased from day 137 to 226 for O2 (24–58%) and from day 137 to 180 for glucose (4–19%), then remained relatively constant. The proportion of gravid uterine α-amino N uptake utilized by the foetus remained relatively constant and averaged 60%. A net secretion of lactate from the utero-placenta to the uterine and foetal circulations was observed and increased as gestation advanced. These data indicate that increased rates of uptake or secretion of metabolites by tissues of the gravid uterus can be explained primarily by increased rates of uterine and umbilical blood flows.

The relationships between organic-matter digestibility (OMD), dry-matter intake (DMI) and the mean retention time (MRT) of unabsorbed solutes in the gastrointestinal tract were examined using six fistulated, cross-bred, castrate male sheep. Measurements were made on each sheep at two different DMIs within the range 28–81 g D.m./(day. kg0·75). There were negative, curvilinear relationships between MRTs (both rumen and total) and DMI and positive, curvilinear relationships between OMD and MRTs. As a consequence, there was a negative, rectilinear relationship between OMD and DMI. OMD declined by 0·022 when DMI increased from calculated maintenance to twice maintenance. The proportion of the total MRT accounted for by rumen MRT did not change significantly; the mean value was 0·364 ( ± S.e. 0·010).

Experiments made for 4 years in the seasonally dry period of the monsoon environment of north-west India showed that the application of farmyard manure (FYM) with the onset of monsoon rains (in early July) was more advantageous for the growth and yield of wheat than its application at the end of the monsoon season in mid-September. Fertilizer N drilled into the soil with the cessation of rains was better utilized by wheat than that applied at sowing in mid-November. A combination of the organic matter and urea was better than their application separately. N, P and K removal by the wheat crop was significantly increased by FYM and urea application. The time of their application influenced the nutrient removal by the crop in the same way as it affected its growth and yield.

Changes in body weight and body temperature were observed in Sudanese desert sheep and goats, which had been subjected to the summer sun (20 °C min. to 42 °C max.), given water normally and then deprived of water for 3 days. Tritiated water was also used to measure total body water and water turnover in these animals together with measurements of plasma and extracellular space, intracellular fluid volume and blood osmolality. The body weight and the size of the fluid compartments decreased in the two species at varying degrees associated with haemoconcentration. The extent of some changes was more marked in sheep than in goats, suggesting better adaptation of the former species to desert life.

Carcass data for 1053 steers from the Meat and Livestock Commission's beef breed evaluation programme were used to examine the relative precision of alternative fatness assessments for predicting carcass lean percentage. The data were from four trials and comprised both dairy-bred and suckler-bred cattle by a wide range of sire breeds.

A visual assessment of carcass subcutaneous fat content to the nearest percentage unit (SFe) was the single most precise predictor both overall (residual S.d. = 2·28) and within breed (residual S.d. = 2·05). Precision was improved by the addition in multiple regression of the percentage perinephric and retroperitoneal fat (KKCF) in carcass, a visual score of the degree of marbling in the m. longissimus and selected fat thickness measurements taken by calipers on cut surfaces (residual S.d. = 2·11 (overall) and 1·90 (within breed)).

When the best overall equation was applied to the breed means, there was substantial bias (predicted – actual carcass lean percentage). Biases ranged from +2·5 (purebred Canadian Holstein and Luing) to – 1·3 (Limousin crosses).

Breeds differed significantly in carcass lean content when compared at equal levels of fatness measurements. The differences depended both on the precision with which the measurements predicted carcass lean content and the observed differences in carcass composition that existed before adjustments to equal fatness were made.

The robustness of prediction equations was examined by applying them to independent sets of data (a total of 334 carcasses) from four other trials involving steers, heifers, cows and young bulls. Equations were stable for cattle of the same breed, sex and similar levels of fatness but important bias was found between more extreme types of cattle.

Two experiments were carried out to test the effects of ryegrass maturity on rumen lipid metabolism. In the first experiment the effect of stage of maturity of perennial ryegrass on lipid metabolism in the rumen was studied with grazing sheep fitted with rumen cannulae. The pasture was either immature (13·8% crude protein), mature (8·1% crude protein) or senescent (5·5% crude protein).

The rates in vitro of triacyl glycerol lipolysis and linoleic acid (18: 2w6) hydrogenation were found to decrease with increasing age of the ryegrass.

In the second experiment the sheep were dosed with emulsified linseed oil (30 g) via rumen cannulae while grazing immature or senescent ryegrass and the rumen digesta and blood plasma sampled at 0, 4 and 8 h after dosing.

The proportions of linseed oil retained in the rumen were greater and blood plasma linoleic (18:2w6) and linolenic (18:3w3) acid concentrations higher when senescent ryegrass was fed.

It was concluded that the rates of rumen lipolysis and hydrogenation decreased with the age of pasture and that after dosing with linseed oil the polyunsaturated fatty acid concentrations in blood plasma increased.

Two varieties of okra were sown at approximately 14-day intervals from 1 April to 1 June for 2 years during the main rainy season in Nigeria. Low soil temperature and moisture, which resulted from a combined effect of high solar radiation, high atmospheric temperature and low rainfall, led to poor seedling emergence at the early sowing dates.

The growth of the fewer plants of the early sowing dates were more vigorous than those of later sowing dates and they attained 50% flowering earlier and had a longer harvest duration. This resulted in increases in number of pods per plant, pod length, pod diameter, pod volume, pod weight and pod yield per ha, indicating compensatory growth by the fewer plants in the early plantings. The relatively lower values obtained for these variables with the late sowing dates were also attributed to possible poor soil aeration arising from the increased rainfall during their growth period.

Sowing dates did not generally affect the percentage moisture, oil and protein in the pods. The effects of varieties on the variables measured were more uniform than those of sowing dates and mostly not significant.

Carcass data for 1053 steers from the Meat and Livestock Commission's beef breed evaluation programme were used to examine the prediction of carcass composition from conformation-related characteristics corrected to equal fatness. The data were from four trials and comprised both dairy-bred and suckler-bred cattle by a wide range of sire breeds.

When used with carcass weight (W) and a visual assessment of carcass subcutaneous fat percentage (SFe) (the most precise simple assessment of carcass lean percentage, residual S.d. = 2·28), m. longissimus area (MLA) at the 10th rib was the most effective conformation-related assessment (residual S.d. = 2·10). Precision was improved by the further addition of a visual conformation assessment (C15) on a 15-point scale (residual S.d. = 2·06). The use of equations combining W, SFe, MLA, C15 and other simple assessments of fatness improved the precision further (residual S.d. = 1·94).

The measurement combinations above also provided a significant prediction of the percentage of total carcass lean distributed in the higher-priced joints. Residual S.d.s were: W + SFe, (1·12); W + SFe + MLA (1·07); W + SFe + MLA + C15 (1·06).

When the equations were applied to the breed means, there was substantial bias (predicted – actual carcass lean percentage). Bias ranged from approximately + 1·5 (purebred Canadian Holsteins and Luings ) to – 1·6 (Limousin crosses). The accuracy of carcass lean prediction was not improved by the addition of bone measurements to the equations but there was some improvement in the prediction of lean to bone ratio: cattle with light, thin bones tended to have higher ratios.

Similar combinations of independent variables were found to provide the most precise prediction within breed.

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.

The pollination requirements of three cultivars of winter and one of spring swede rape (Brassica napus), grown in a glasshouse, were compared. All cultivars yielded more when hand-pollinated than when auto-pollinated but were self-fertile and yielded equally well whether self- or cross-pollinated. In most cultivars plants that were shaken to simulate movement of plants by wind yielded more than autopollinated plants and not significantly differently from hand-pollinated plants. Handpollinating and shaking plants also increased the set of early flowers.

Two experiments were carried out to study the effects of five agronomic variables on the marketable yield of transplanted leeks. In the first experiment two cultivars were used, cvs Splendid and Winterreuzen, and the treatments compared three plantraising systems, two ages of transplant when planted, and two plant population densities, two row spacings and two levels of nitrogen nutrition in the field. In this experiment some treatment interactions were confounded with each other.

In the later experiment only cv. Splendid was grown. There were two plant-raising systems, two plant-raising temperatures, two plant-raising nutrition levels, two times of transplanting (63 or 84 days from sowing) and four different sowings (7 and 28 February, 20 March and 10 April 1984). The duration of the growth period in the field was standardized by harvesting each treatment combination on two occasions, 168 and 189 days after transplanting.

The results from the first experiment showed that plants raised in modules at high temperature, planted early at a high plant density with higher than normal levels of nitrogen gave high marketable (> 12·5 mm in diameter) yields of 7·31 kg/m2, greater than that from any other treatment combination. The second experiment confirmed these general trends but also showed that the date of transplanting was of critical importance with the earliest plantings in the year giving the highest yields and with later plantings resulting in progressively lower yields irrespective of the way in which the transplants were raised. Comparisons with meteorological data showed that decreasing yields were associated with decreasing values of accumulated solar radiation and accumulated day-degrees during field growth.

These results are discussed in relation to other published data. They do not support some of the current recommendations for growing the crop but suggest that much more work needs to be done on production systems for this crop because of the potential for increasing marketable yields.

Tubers from nine cultivars grown in four plantings over 3 years at two sites in Scotland were tested for resistance to cracking by squeezing between two flat surfaces. The force was applied by a lever to which a steel plate was fixed, pressing the tuber against a wooden base. The weight on the lever was recorded when wet hair-line cracks appeared on the tuber surface.

There were significant differences between cultivars from the same planting. The rank positions of some cultivars were relatively stable but others differed widely between plantings. The grouping of cultivars into the upper, middle or lower parts of the range for squeezing resistance was similar to that for resistance to external damage based on Potato Marketing Board farm surveys. The test could be used to help breeders identify genotypes highly susceptible to external mechanical damage. If combined with tests of resistance to other types of mechanical abuse common in the bulk handling of tubers a more accurate estimate of damage resistance on the farm should be possible.

Normal and brown midrib-3 (bm3) maize silages were fed to sheep, lactating cows and dairy calves to determine the effect of the bm3 gene on in vivo digestibility, dry-matter intake and animal performance.

In two trials wether sheep were fed either normal or bm3 maize silage at maintenance level. In the first experiment the bm3 gene significantly increased the digestibility of the organic matter(OM), cell wall constituents (CWC), acid-detergent fibre (ADF), cellulose and hemicellulose from 76·9, 74·7, 67·3, 74·2 and 79·5% to 79·6, 79·2, 75·8, 80·8 and 81·5%. In the second experiment the gene increased the digestibility of the OM, CWC, ADF and cellulose from 65·9, 44·7, 28·5 and 38·7% to 701, 59·3, 560 and 66·1, 39·1,32·8, 40·4 and 45·5% to 68·1, 51·9, 53·7, 58·0 and 49·2%. The digestibility of the protein was similar for both diets.

In a feeding trial 6-month-old calves were fed either normal or bm3 silage ad libitum together with 1·6 kg D.M. of a protein supplement. The dry-matter intake of the two silages was similar; however, the daily live-weight gain of 0·92 kg for calves fed the bm3 diet was significantly higher than the 0·83 kg for calves fed the normal diet.

The effect of glucagon on the rate of glucose production in the presence of alanine, of lactate and of propionate has been studied in isolated perfused livers obtained from foetal, suckling and weaned lambs.

Glucose utilization occurred in foetal livers in the absence of glucagon whereas addition of glucagon resulted in a net production of glucose from the three substrates. In livers from suckling and weaned lambs addition of glucagon was not essential for glucose production to occur and the stimulation of gluconeogenesis by added glucagon was less evident in the older lambs. The effect of glucagon was not dependent on changes in the rate of substrate uptake.

It is concluded that gluconeogenesis will be induced by glucagon in foetal lambs when their mothers are severely undernourished, and that placentally derived lactate could contribute up to 90% of the glucose synthesized.

The effect of six intervals between harvests and three levels of N application on the concentration of nitrate-N and total N in total herbage, green leaf and ‘stem’ was studied in two varieties of perennial ryegrass during 30-week periods in each of the first two harvest years of a field experiment. The effect of two intervals between harvests on the concentration of nitrate-N in Italian ryegrass total herbage was studied in the same experiment. The effect of two intervals between harvests and three levels of N application on the concentrations of nitrate-N and total N in total herbage was studied in five grasses during a 32-week period in a second field experiment.

Increasing the interval between harvests tended to increase the concentration of nitrate-N in herbage; however, this seemed due mainly to the average date of harvest being later in the year with the longer intervals. The concentration of nitrate-N in herbage increased from June to September. Italian and hybrid ryegrass and tall fescue were much higher than perennial ryegrass in nitrate-N concentration at the highest level of applied N (525 kgN/ha per year). Apart from the species and time of year effects, the nitrate-N concentration seemed to be determined mainly by the amount of N applied divided by the number of days between the date of application and the date of sampling. The ‘stem’ of perennial ryegrasa tended to be slightly higher in nitrate-N concentration than green leaf. The proportion of nitrate-N in total N was increased by increasing the interval between harvests and by applying N and was nearly twice as high in ‘stem’ as in green leaf. Both the nitrate-N and the total N concentration of herbage, particularly the latter, seemed to be inversely related to solar radiation receipt.

Field experiments were carried out at Ludhiana in Punjab during 1982 and 1983 on the effect of foliar application of water spray or naphthalene acetic acid (NAA) at 100 and 200 mg/1 of water on the growth and yield of rice when applied at tillering and before panicle emergence stages of late-transplanted paddy grown under four levels of nitrogen (0, 60, 90 and 120 kg/ha). Foliar spray of NAA significantly increased the grain yield of paddy as compared with water spray under low levels of nitrogen (0 and 60 kg/ha) owing to increases in the number of ear-bearing shoots per plant, number of filled grains per panicle and grain weight. Chlorophyll content of leaves, leaf area index and interception of photosynthetically active radiation by the crop canopy also increased with foliar spray of NAA and application of nitrogen. Paddy responded significantly up to 90 kg N/ha in terms of grain yield whereas straw yield increased significantly up to 120 kg N/ha. However, grain mass declined significantly with increase in nitrogen from 90 to 120 kg/ha.

Two trials were carried out to compare the milk yield, milk composition and the rate of growth of naturally or artificially reared kids and lambs of Damascus goats and Chios sheep.

Milk yield until weaning was similar in sheep and goats, but goats produced significantly more milk after weaning. Sheep milk was higher in total solids, fat, protein, lactose, ash and calorific value.

Lambs and kids grew similarly during the ad libitum milk feeding period but lambs grew faster during the restricted milk feeding period. Solid feed intake of lambs until weaning was higher than that of kids and the results indicated that the rumen develops later in kids than in lambs. During the post-weaning period lambs consumed more feed, grew faster and utilized feed more efficiently than kids. Lambs were more sensitive to high copper supply than kids.