bluuebunny/crossref_metadata_2025 huggingface dataset:
Aspects of the agronomy and genetics of quality components in a diallel set of progenies of Lolium perenne L.
Authors: Rogers H. H. , Thomson A. J.
Published: March 2009

Selfed and diallel progenies of selected clones of Lolium perenne were subjected to four nitrogen rates—0, 225, 450 and 675 kg/ha of N per annum. The herbage was analysed for total nitrogen (N), digestible dry matter (DMD), digestible organic matter (D) and acid-pepsin solubility was determined on total (PS) and organic matter (POMS) in 1967 and 1968.

Data for the percentage composition and the yield of quality components are presented with the variances of general (g.c.a.) and specific (s.c.a.) combining abilities for these characters. The g.c.a. and s.c.a. interaction with nitrogen is partitioned.

For percentage quality components and yields there were significant effects of years, nitrogen rates, progenies and their interactions. The variance for g.c.a. for all percentage quality components was not significant in 1968 but in 1967 all were significant except for total N. For yields, only the g.c.a.'s for PS and POMS were significant in 1967: no g.c.a.'s were significant in 1968.

There were considerable differences between years for heritability values. For digestibility the predicted performance of a theoretical F2 synthetic was little better than the mean of the population from which it was derived.

The implication of these studies in the formulation of a grass breeding programme is outlined.
Interactions between the beneficial effects of nitrogen, phosphate and potassium on plant growth
Authors: Wood J. T. , Greenwood D. J. , Cleaver T. J.
Published: March 2009

Sets of data were selected from 66 nutritional experiments on crop plants with large beneficial effects of at least two of the nutrients, nitrogen, potassium and phosphorus, and the data, the logarithms of the data, and the reciprocals were statistically analysed. It was shown that the beneficial effects of the nutrients were additive much more often on the reciprocal scale, than when a logarithmic transformation, or none at all, was used.
Rapid reduction of nitrate in soil re-moistened after air-drying
Authors: Cawse P. A. , Sheldon D.
Published: March 2009

When an organic calcareous soil was air-dried for 2 days and re-wetted to a wide range of moisture contents, well below saturation, nitrite accumulated within 1–2 days. At the same time much nitrate was formed and more carbon dioxide was released than from soil kept moist. On further incubation of re-wetted soil for 3–5 days, the nitrite concentration decreased rapidly. Since 15N-labelled nitrate was reduced to nitrite after air-drying and re-wetting, and no nitrite was formed in autoclaved soil, nitrate was microbially reduced.

Eighty-three per cent of added 15N tracer was recovered from the soil 2 days after re-wetting to 70 % moisture, indicating that 58 ppm N had been lost; 10 ppm N of this was released as nitrous oxide. Autoclaved soil to which nitrite was added did not evolve nitrous oxide, suggesting that nitrite was reduced biologically rather than decomposed chemically.

Three other soils were treated similarly; two, which were non-calcareous, accumulated no nitrite. Fresh calcareous soils with high respiration rates and good capacities to denitrify when waterlogged are most likely to form nitrite after drying and moderate re-wetting.
Effect of disease on the oestrogenic activity and coumestrol content of white clover and lucerne
Authors: Saba N. , Drane Hilary M. , Hebert C. Nancy , Newton J. E. , Betts J. E.
Published: March 2009

The oestrogenic activity and coumestrol content of ‘diseased’ and ‘clean’ white clover and lucerne were investigated. It was found that both coumestrol content and oestrogenic activity were increased in diseased white clover. However, there was insufficient coumestrol to account for the oestrogenic activity and it was suggested that other factors (e. g. oestrogen potentiator, unidentified oestrogen) were involved.
The effects of grazing intensity on herbage consumption and animal production: IV. An evaluation of two methods for avoiding the rejection of fouled herbage by dairy cows
Authors: Reid G. W. , Greenhalgh J. F. D. , Aitken J. N.
Published: March 2009

For phase I of a rotational grazing experiment (three grazing cycles; May–July) a group of nine cows (group S) were ‘conditioned’ to eat fouled herbage by being allowed to graze only on slurry-treated pasture (area 1), and two further groups of nine (groups H and C) grazed on an adjacent area (2) of untreated pasture. One-third of area 2 was harrowed after each grazing. During phase II (the fourth grazing cycle; August) group H grazed on the harrowed part and groups S and C grazed on the remainder of area 2. The herbage allowance was 15 kg dry matter per cow per day in phase I and 12 kg in phase II.

In phase I, group S cows ate significantly less than groups C and H combined (9·2 v. 10·5 kg organic matter per day), and lost weight (– 0·37 v. + 0–03 kg/day), but their milk yields were not significantly lower (16·1 v.16–6 kg/day). In phase II neither intake nor milk yield differed significantly between the three groups, but group S cows gained weight while the other two groups lost weight.

It was concluded that neither conditioning the cows nor harrowing the pasture was an effective means of avoiding rejection of fouled pasture.
Yield, leaf-area index and photosynthetic rate in some perennial ryegrass (Lolium perenne L.) selections
Authors: Rhodes Ian
Published: March 2009

Yield, critical LAI and apparent photosynthetic rate per unit leaf area were measured in four families selected from L. perenne S. 321. Differences in yield were attributable to differences in canopy structure producing differing critical LAI. The most productive family, which was 33% more productive than the base population, produced the largest critical LAI but had the lowest photosynthetic rate.
The effects of partial suckling on the lactation performance of Chios sheep and Damascus goats and the growth rate of the lambs and kids
Authors: Hadjipanayiotou M. , Louca A.
Published: March 2009

Two trials with 82 and 54 Chios ewes and one with 44 Damascus goats were conducted during 1973–4 to study the effects of partial suckling on lactation performance and the growth rate of the lambs and kids. The treatments studied were: (a) continuous (24 h a day) suckling; (b) partial (8 h a day) suckling and (c) partial with decreasing duration of suckling from 8 h daily to residual suckling, i.e. 20 min after each milking.

No significant differences were found in either the 35-day milk yields (commercial milk yield+milk sucked) of ewes or the 70-day milk yields of goats between animals suckling continuously and those suckling partially. However, the 35-day and 70-day commercial milk yields of ewes and goats on the partial suckling treatments were significantly higher than those of ewes and goats on the continuous suckling treatment. Residual suckling of ewes from 36 to 120 days after lambing resulted in an increase in the total milk yield but not in the milk sold. Significant differences in milk yields were found between ewes nursing one and those nursing two lambs. The corresponding mean values for the 35-day milk yield were 78 and 94 kg and those for the 120-day milk yield 205 and 238 kg.

Up to weaning (35 days for sheep and 70 days for goats) the growth rate of lambs and kids on the partial suckling treatments tended to be poorer than that of those on continuous suckling. After weaning, however, the growth rate of the partially suckled lambs and kids as well as that of the lambs on residual suckling from 36 to 120 days were as good as that of those suckling continuously so that the differences in the final weight were not significant.

It is concluded that partial suckling in sheep and goats is profitable in the early stages of lactation provided that the milk left to the young and the intake of solid feed are sufficient to sustain satisfactory growth.
Developmental characteristics of grass varieties in relation to their herbage production: 2. Spring defoliation of Dactylis glomerata: the fate of reproductive tillers which are cut, but whose stem apex is retained
Authors: Davies I.
Published: March 2009

Early stages in the development of reproductive tillers of cocksfoot were studied in uncut swards, and in regrowth after cuts taken at a critical stage.

In uncut swards, initial stages of stem extension (up to 10 cm) occurred over 3 weeks. During this period the last three or four leaves initiated on the tiller became visible externally. Tillers with stems of less than 2 cm generally had one or two partially emerged blades. Those with stems 2–6 cm long carried two, three or, occasionally, four partially emerged blades; the sheaths of two, and sometimes three of these leaves extended beyond the stem apex. Hence, for tillers with 2–6 cm stems, even lenient defoliation involving the removal of only one expanded blade would result in the severance of a further two, three or four developing leaves; at an earlier stage only one or two developing leaves would be severed.

In the regrowth studies it was found that defoliation of reproductive tillers whose apices were below cutting height and which, at the time of cutting, had stems of up to 8 cm, led to contrasting effects: some made only negligible regrowth, whilst others made rapid extension growth. Some of the most rapidly extending tillers retained no leaf blades, and therefore the alternative effects of defoliation cannot be completely explained in terms of leaf retention. Other possible mechanisms contributing to these effects are discussed.
The effect of density of planting on the growth of two Phaseolus vulgaris varieties in England
Authors: Lucas E. O. , Milbourn G. M.
Published: March 2009

The growth and development of two varieties of Phaseolus vulgaris (Purley King and Limelight) were compared in two experiments in 1973 and 1974 at a range of planting density from 20 to 100 seeds/m2. Within this range, the relationship between seed yield and density in Purley King was asymptotic, although there was a suggestion that if even higher densities had been tested, a downward trend in yield might have occurred. The optimum density of planting for Purley King in Expt 1 was 50 seeds/m2 while that for Limelight was 40 seeds/m2. The corresponding densities in Expt 2 were 75 and 50 seeds/m2 respectively. Although number of branches per plant generally decreased with increasing density, there was no significant density effect on the number of nodes per plant. Thus stabilization of seed yield occurred even at quite low densities. Although in the low-density treatments, less vegetative tissue was produced, the peak of dry-matter yield occurred later after flowering and the slower subsequent senescence ensured the presence of active photosynthetic tissue throughout the pod-fill stage. Less pod retention occurred at high density which, combined with the ability of widely spaced plants to produce pods over a longer period, resulted in a similar number of pods per unit area over a wide range of density.

Although the variety Purley King produced more than double the number of mature pods from its extra nodes and branches, it was outyielded by Limelight by 35% from the combined effect of more seeds per pod and a higher mean seed weight. Limelight also produced this high yield with less vegetative tissue. In both varieties it appeared that pod photosynthesis could take place, in Purley King because the pods were borne on higher nodes above the canopy and in Limelight due to the earlier senescence of its smaller leaf area. However, in spite of the apparent physiological advantages of Limelight, the pods are not borne high enough on this plant to enable satisfactory mechanical harvesting.
Effects of pre-mating environmental stress, ACTH, cortisone acetate or metyrapone on oestrus and ovulation in sheep
Authors: Doney J. M. , Gunn R. G. , Smith W. F. , Carr W. R.
Published: March 2009

Administration of ACTH to Finnish Landrace × Dorset Horn ewes during days 13–16 of the pre-mating oestrous cycle resulted in a significant delay in the onset of oestrus (mean cycle length of 17·5 ± 0·39 days as compared with 16·4 ± 0·61 in a control group). Subsequent ovulation rate was significantly higher than in the control group (3·12 and 2·44 ova/ewe respectively).

In a second experiment with Scottish Blackface ewes the effects on time of onset of oestrus and on ovulation rate of environmental stress, ACTH, cortisone acetate or metyrapone were studied. Environmental stress and administration of ACTH through the oestrous period significantly reduced ovulation rate (1·54 and 1·39 ova/ewe respectively) compared with the control (1·96). ACTH administered during days 13–16, as in the first experiment, and cortisone acetate administered through oestrus had no effect on ovulation rate (1·88 and 1·86 respectively). Administration of metyrapone reduced ovulation rate to 1·70 but this was not significantly different from the control. Both forms of ACTH treatment resulted in a delay in onset of oestrus but environmental stress had no effect on this character.

Levels of plasma luteinizing hormone (LH) were estimated on representative animals. These showed that ACTH and environmental stress influenced the pattern of the ovulatory surge of LH in respect of time of onset of the surge relative to onset of oestrus, duration of surge and peak levels.
Effects of post-mating environmental stress or administration of ACTH on early embryonic loss in sheep
Authors: Doney J. M. , Smith W. F. , Gunn R. G.
Published: March 2009

In two separate experiments, ewes of the Scottish Blackface breed were subjected to management stresses in the first or second 10-day period after mating or were treated with daily injections of 60 i.u. ACTH for the whole 20-day period. Embryonic loss is defined as the number of corpora lutea not represented by viable embryos at slaughter. Examinations were carried out between 26 and 32 days post-mating. In the two experiments combined, losses were 29·9, 29·0, 37·7 and 17·2%, respectively, for ewes subjected to environmental stress during days 1–10, during days 11–20, treated with ACTH or kept as unstressed control. Expressed as the percentage of ewes in which partial or complete loss of shed ova occurred, the results were 49·0, 46·0, 54·3 and 25·5%, respectively. Losses were significantly higher in all treated groups than in the unstressed control.
Density and row spacing effects on irrigated short wheats at low latitude
Authors: Fischer R. A. , I. Aguilar M.  , R. Maurer O.  , S. Rivas A.
Published: March 2009

During four winter seasons eight spacing and density experiments were made under irrigated high fertility conditions in north-west Mexico (latitude 27° N). Experiments included various Triticum aestivum and T. durum genotypes of spring habit, short stature derived from Norin 10 genes, and contrasting plant type. Measurements included dry-matter production, photosynthetic area index, and light interception during one experiment, total dry matter at maturity in most others and grain yield and its numerical components in all experiments.

Grain yield and most other crop characters were unaffected by row spacings within the range 10–45 cm interrow width. The optimal seeding density for maximum grain yield was 40–100 kg/ha (80–200 plants/m2). Yield reductions at lower densities (20, 25 kg/ha) were slight and accompanied by reduced total dry-matter production. Yield reductions at higher densities (160–300 kg/ha) were also slight and were associated with more spikes/m2 but fewer grains/m2 and reduced harvest index. It is suggested that lower than normal preanthesis solar radiation or weather conditions leading to lodging can magnify these yield depressions at higher densities.

Measurements showed rapid approach of crops to 95% light interception, reached even at a density of 50 kg/ha within 50 days of seeding. It is suggested that provided this occurs before the beginning of substantial dry-matter accumulation in the growing spikes (60 days after seeding) there will be no loss of grain yield with reduced seeding density. Results point to a ceiling photosynthetic area index for maximum crop growth rate although there was a tendency for rates to fall at very high indices (> 9). This tendency was associated with very high density, high maximum numbers of shoots, poor survival of shoots to give spikes (< 30%) and reduced number of grains/m3;. The relatively low optimal densities seen here may be characteristic of genotypes derived from Norin 10.

Genotype × spacing, genotype × density and spacing × density interactions were generally non-significant and always small. There was a tendency for the presence of non-erect leaves or branched spikes to reduce the optimal density, but large differences in tillering capacity had no influence. Differences in lodging susceptibility can however lead to substantial genotype x density interactions.
Seasonal changes, breed differences and repeatability of plasma copper levels of sheep at pasture
Authors: Wiener G. , Field A. C.
Published: March 2009

Plasma copper levels were determined at intervals of 9 weeks over a period of 1 year on 131 female sheep of a grassland flock starting at the age of 5 months in September. The 107 survivors were re-bled 3 years later. There was a steady decline in copper levels from about 100 µg/100 ml plasma in November to about a third of that level at the beginning of the following June. Thereafter there was a partial recovery in level.

Three breeds, Scottish Blackface, Cheviot and Welsh Mountain and their crosses were represented. There were marked differences in plasma copper level among the breeds with cross-breds having levels as high or higher than the corresponding pure breeds. Breed differences in copper levels were already present at 5 months old. Part of the breed differences in copper levels were attributable to differences among the breeds in the frequency of the HbA and HbB alleles.

Correlations were calculated among the plasma copper levels from successive bleedings for individuals within breeds and subclasses. From the time the sheep reached about 9 months old these correlations ranged from 0·4 to 0·9 including bleedings more than 3 years apart in time.
The examination of some winter hardiness components in grasses using canonical variate analysis
Authors: Thomson A. J.
Published: March 2009

Winter vigour, winter burn, freezing damage and early spring yield were measured in 24 perennial ryegrass varieties which varied in their degree of winter adaptation. Winter vigour and winter burn were negatively correlated due to senescence in the dormant varieties. Cold resistance, measured in a freezing test, was also negatively correlated with winter burn but was independent of spring yield. Spring yield was positively related to winter vigour but negatively related to winter burn. The more dormant varieties which sustained most winter burn were better able to survive freezing.

A canonical variate analysis showed that the first two canonical variates accounted for 87·8% of the total variation. Interpolation from the means of the four characters suggested that the first canonical variate represented adaptation to winter conditions. A generalized model based on these findings is proposed and its use in the formulation of grass breeding strategies discussed.
Rumen fermentation studies on two contrasting diets. 2. Comparison of the performance of anin vitrocontinuous-culture fermentation within vivofermentation
Authors: Barry T. N. , Thompson A. , Armstrong D. G.
Published: March 2009

An impermeable continuous-culture artificial rumen was constructed and rumen microbial populations were culturedin vitrofor periods of up to 23 days. Diets of hay and 20:80 hay:cooked flaked maize (concentrate diet) were fed to thein vitrocultures and also to sheep, and the performance of thein vitrofermentation compared with that of thein vivofermentation.

With the hay diet, changing the initial inoculum from strained rumen liquor to unmodified rumen contents (containing solid ingesta) reduced the time required to attain a steady-state fermentationin vitrofrom 13 to 4 days. VFA molar proportions and the CO2: CH4ratio indicated that the type of fermentation taking placein vitrowas remarkably close toin vivofermentation. However, rates of cellulose digestion, CH4production and number of bacteria/unit volume (as judged by DNA concentration) were much lessin vitrothanin vivo, showing that the rate of fermentation was reduced in the artificial rumen. Total VFA concentration and the osmotic pressure of fermentor liquor were slightly higher than the maximum values foundin vivo, and it was concluded that these were responsible for the reduced rate of fermentation.

Regardless of the duration of culture, a satisfactory steady-state fermentation was never attained when the concentrate diet was administered. DNA concentration in fermentor liquor declined to very low levels after 4 days; CH4production rapidly declined and was replaced by H2production after 5 days. VFA molar proportions bore little resemblance to those foundin vivo. Both the osmotic pressure of fermentor contents and total VFA concentration rapidly increased with time, and by day 3 were approximately 2·5 times the values foundin vivo. It was concluded that high VFA concentration, and the associated increase in osmotic pressure, were the main factors responsible for the unrealisticin vitrofermentation, and that this problem was much greater than encountered with the hay diet due to starch being digested at a faster rate than cellulose and hemicellulose.

Methods of regulating VFA concentration in continuous culturein vitrorumen systems are discussed and some improvements suggested.
Zinc nutrition of onions as influenced by phosphorus
Authors: Asif M. I. , Khan A. A. , Ajakaiye M. N.
Published: March 2009

In a field study it was found that application of high P induced Zn deficiency symptoms on onion (Allium cepaL.) plants, increased P concentration but decreased that of Zn. Conversely, application of Zn tended to increase Zn concentration of both tops and bulbs and lowered P concentration. Effectiveness of Zn varied with the amount of P applied. Evidently P and Zn are mutually antagonistic. Using sub-soil on the top of raised beds and heavy P fertilization appear to be responsible for inducing Zn deficiency in onions in northern Nigeria.
Total nitrogen concentration in leaves of potatoes (Solanum tuberosumL.) as an index of nutritional status
Authors: Gupta A. , Saxena M. C.
Published: March 2009

Leaf samples were collected, at weekly intervals, throughout the growing season, from potato (Solanum tuberosumL.) plants supplied with varying amounts of nitrogen (0, 60, 120, 180 and 240 kg N/ha) and analysed for total N. Application of nitrogen increased the N concentration in the green leaves at all stages of growth. There was a significant curvilinear relationship between the final tuber yield and the total N concentration in the leaves at 48–90 days after planting in 1968–9 and at 79–107 days after planting in 1969–70. The N concentration at 70–90 days after planting was consistently related to the final tuber yield in both years. Thus this period was ideal for assessing the nitrogen status of potato plants. The critical concentration of total nitrogen generally decreased with advance in age. It ranged from 4·65% at 76 days to 3·30% at 90 days during 1968–9, whereas in 1969–70 it ranged from 4·20% at 79 days to 3·80% at 93 days. During the period from 83 to 86 days the critical percentage was around 3·6% in both the years.
In situ estimation of root length at natural soil profiles
Authors: Böhm W.
Published: March 2009

A thin layer of soil was washed from a smoothed soil profile and the length of the roots visible at the profile wall estimated. A grid net was used to count every visible part of a root which was nearly 5 mm long. Roots which were longer than 5 mm were counted more than once. This improvement of the traditional trench profile method provides an estimate of the root length in a soil volume.
Pollination as a factor limiting the yield of field beans (Vicia faba L.)
Authors: Free J. B. , Williams Ingrid H.
Published: March 2009

Self-pollinating and cross-pollinating by hand samples of flowers in field bean crops usually gave an increased set of seed compared with control flowers left to be pollinated naturally. Hence, insect pollination of field bean crops is often inadequate. In large fields of more than 12 ha the seed yield was greater by plants near the edge than near the centre. Fewer pods were produced from nodes at the upper than the lower parts of a stem, and they contained fewer seeds which were of a smaller size.
Statistical procedures for distinctness, uniformity and stability variety trials
Authors: Weatherup S. T. C.
Published: March 2009

This paper describes statistical methods for analysing data arising from distinctness, uniformity and stability variety trials carried out to fulfil Statutory Regulations in the United Kingdom. Both univariate and multivariate methods are considered. It is shown that multivariate techniques can separate some variety pairs which could not be separated using univariate methods. A computer system for routinely analysing these trials is also described.
Multifactorial experimentation on continuous winter wheat grown in sandy clay soil at Saxmundham, Suffolk
Authors: Widdowson F. V. , Johnston A. E. , Penny A.
Published: March 2009

We present results from an experiment at Saxmundham measuring the effects of growing different numbers of successive winter wheat crops, each year, from 1971 to 1976; it followed five cropping sequences introduced from 1966 to 1970.

From 1971 to 1973 four seed rates, two row spacings and three nitrogen rates were tested in all combinations with four of the previous cropping sequences. The remaining sequence was sown traditionally for continuity. Number of ears, leaf area, yield and nutrient content showed little benefit from increasing or decreasing seed rate, around that usually sown. Rows 15 cm apart gave the largest yield independently of N, because they produced most ears. There was no loss in yield from growing up to eight consecutive crops of winter wheat. 100 kg N/ha was sufficient for maximum yield.

From 1974 to 1976 two varieties of different potential (Cappelle-Desprez and Maris Huntsman), chlormequat chloride (CCC), three amounts of N, as single, or as divided dressings, were tested in all combinations with the four cropping sequences. The fifth sequence again was sown traditionally, but with or without autumn-applied N. Maris Huntsman gave a grain yield only 0·22 t/ha larger (4·5%) than that of Cappelle-Desprez, and mean yields were larger (also by 4·5%) where CCC was given. Divided dressings of N increased yields by 0·11 t/ha (2·2%). The mean increase in yield from adopting all three improvements was 0·5 t/ha (or 11%). Yields of the 10th and 11th consecutive wheats declined, probably because black grass (Alopecurus myosuroides) became abundant. There was a good inverse relationship between losses of N in drainage during winter and subsequent yield and grain nitrogen uptake, which helped to explain large yield variations from year to year.
A mathematical model of fertilization failure and early embryonic mortality in sheep
Authors: Geisler P. A. , Newton J. E. , Mohan A. E.
Published: March 2009

The reproductive potential of a sheep system is much reduced by the failure of released ova to be fertilized and to survive to parturition. This paper looks at currently available information on fertilization failure and early embryonic deaths. Separate hypotheses are proposed for fertilization and for early embryonic mortality. For fertilization, the hypothesis is that a ewe that mates with a ram will end up with either all or none of her released ova fertilized. For embryonic mortality, the hypothesis is that the survival of a fertilized ovum depends only on how many ova were released with it and is independent of the survival or death of those released with it. A mathematical model is constructed on these hypotheses and its predictions are compared with published experimental results of other workers.
The influence of loss of plumage on temperature regulation in laying hens
Authors: Richards S. A.
Published: March 2009

summary

The acute thermoregulatory responses of normally feathered (control) and poorly feathered laying hens were studied in the ambient temperature range from 0 to 38 °C.

Core body temperature in the poorly feathered birds began to fall at between 15 and 20 °C but this difference from the controls was significant only at 0 and 5 °C, when there was severe hypothermia. The temperature on the skin of the back was significantly lower at 20 °C and below, but the comb temperatures did not differ.

The rate of oxygen consumption in the poorly feathered hens was significantly higher than that of the controls at 30 CC and below; at the acclimation temperature (20–25 °C) the difference was about 62%. The rate of increase of heat production with falling ambient temperature was 2–6 W/ma/°C in the poorly feathered group and 1–0 W/ma/°C in the controls.

Absolute rates of evaporative heat loss did not differ between the two groups.

The ratio of the coefficients of dry heat transfer in the poorly feathered and control birds at 0–30 °C was 2–1:1.
Insulin-secreting ability in Pietrain and Large White pigs
Authors: Gregory N. G. , Lovell R. D. , Wood J. D. , Lister D.
Published: March 2009

summary

Mesomorphic, stress-sensitive Pietrain pigs were found to have a lower insulin secretory response to intravenous tolbutamide, glucose and arginine, when compared with ectomorphic, stress-resistant Large White pigs. Pietrain pigs have also been observed to be insulin-insensitive in comparison with Large White pigs. The combination of a low production of and low sensitivity to insulin in the Pietrain breed could account for their enhanced sensitivity to lipolytic agents and for their reduced ability to deposit body fat.
Interactions between dietary carbohydrate and nitrogen and digestion in sheep
Authors: Oldham J. D. , Buttery P. J. , Swan H. , Lewis D.
Published: March 2009

Rumen fermentation, duodenal digesta flow and N balance were studied in three sheep fed diets which contained urea or fishmeal as nitrogen supplement and either barley straw, barley + corn starch or molassed wheat straw (60% molasses) as carbo-hydrate source.

The molar composition of rumen volatile fatty acids (VFA) with straw diets was high in acetate (64–68%), with barley diets high in propionate (32–36%) and with molasses diets high in butyrate (28–34%). Rumen ammonia concentrations (RAC) were low and constant with fishmeal diets (< 10 mM) but varied with carbohydrate source with urea diets. RAC was very high (24 mM) after feeding molasses + urea.

With barley and molasses diets 73–75% of digestible dry matter (DDM) was digested in the stomach, but only 54–59% with ground and pelleted straw diets. For all diets less N passed the duodenum than was eaten. The lowest daily duodenal N passage was with molasses + urea. Daily urinary N output was highest (P < 0·01) for this diet and nitrogen balance lowest.

Daily intakes of amino acids differed widely between diets but differences in duodenal passage were not so great. Molasses + urea provided the lowest values for daily duodenal amino acid flow. The amino acid content of duodenal N (mM amino acid/16 g N) was relatively constant despite broad variation between diets. Digesta alanine and valine (mM/16 g N) were higher for barley than for straw diets (P< 0·05). Digesta methionine (mM/16 g N) was lower for fishmeal than for urea diets (P< 0·01).

Very little sucrose reached the duodenum with any diet.

It was concluded that the form of energy-yielding nutrient inuflenced duodenal N flow by affecting ammonia-N capture in the rumen, but that the amino acid content of duodenal N was little affected. The interaction between molasses and urea was not beneficial to efficient use of urea-N in this work when molasses was the major carbohydrate component of the diet.
Changes in albumin, globulin, glucose and cholesterol concentrations in the blood of dairy cows in late pregnancy and early lactation and relationships with subsequent fertility
Authors: Rowlands G. J. , Manston R. , Stark A. J. , Russell A. M. , Collis K. A. , Collis S. C.
Published: March 2009

Weekly blood samples were collected from 42 Friesian cows between 5 weeks before and 10 weeks after calving, and analysed for serum cholesterol, albumin, total protein, glutamate-dehydrogenase, sorbitol-dehydrogenase and ornithine-carbamyl-transferase and blood glucose.

Cholesterol concentrations increased 2½-fold during the first 8 weeks of lactation. There was also a transient decrease in glucose concentration at calving, but there was no relationship between conception rate and the concentrations of these two constituents.

Albumin concentrations decreased at calving in some but not all cows and remained low for up to 2 weeks. Average concentrations of albumin determined by two analytical methods, a HABA dye-binding and a single radial diffusion assay method, were significantly lower (P< 0·05) between 0 and 2 weeks post-partum in eight cows which required four or more services than in 32 cows which conceived after fewer services. Similarly, the average decrease in concentration over calving was greater in those cows which conceived only after four or more services (P < 0·01).

Globulin concentrations (total protein minus albumin) decreased during the 5 weeks before, and increased in the 3 weeks following calving. The net change over calving was significantly related to conception rate, and the albumin/globulin ratio was reduced (P< 0·001) in the eight cows requiring four or more services.

Activities of all three enzymes doubled after calving, but there was no correlation between these increases and the decreases in albumin concentration, suggesting that, if liver insufficiency is a factor, it is probably due to malfunction rather than tissue damage.
Concentration of N, P and K in leaves, straw and grain of wheat and barley as influenced by N and P fertilizers under semi-arid conditions
Authors: Orphanos P. I. , Krentos V. D.
Published: March 2009

The N, P and K contents of leaves, straw and grain of the durum wheat Kyperounda, the aestivum wheat Pitic 62 and Athenais barley under semi-arid conditions (150–400 mm) as influenced by N and P fertilizers are reported (N rates: 0–105 kg/ha; P rates: 0–26 kg/ha).

Fertilizer N increased linearly the N content of the leaves, straw and grain as well as the K content of leaves and straw, but slightly reduced P content of the grain. Straw K content was increased relatively more in Athenais barley. Such increases of N and K content occurred beyond the N rates giving maximum grain and sheaf yields. Increased K content of the straw resulting from fertilizer N is wasteful where the straw is removed, and accelerates depletion of soil K. Durum wheat grain containing more than 2–8% N showed less than 6% yellow berry (mealy grains) but at lower N contents yellow berry could be high or low depending on location.

Fertilizer P did not significantly influence the P content of any of the components analysed even though it increased grain and straw yields, particularly in the drier years.
The effect of the reproductive state of ewes on their voluntary intake of diets varying in straw content
Authors: Owen J. B. , Lee R. F. , Lerman P. M. , Miller E. L.
Published: March 2009

Two experiments, involving a total of 112 sheep, are described, in which ewes at different reproductive states were given complete diets with a varying grain: straw ratio. In Expt 1 ewes at three reproductive states (dry, pregnant and lactating) were given diets with four levels of coarsely ground oat straw (10, 25, 40 and 55% straw). In Expt 2 ewes in five reproductive states (early pregnancy, mid pregnancy, late pregnancy, lactation and dry) were given a basal diet similar to that given in Expt 1 but with five levels of straw (15, 25, 36, 45 and 55% straw).

The results showed that the intake of ewes varied with reproductive state, the highest intakes occurring during lactation. No significant diet × reproductive state interaction was observed which suggests that in ewes the physiological state can override some of the physical limitations to intake imposed by increased dietary roughage concentration.
Genetic improvements in winter wheat yields since 1900 and associated physiological changes
Authors: Austin R. B. , Bingham J. , Blackwell R. D. , Evans L. T. , Ford M. A. , Morgan C. L. , Taylor M.
Published: March 2009

Experiments were carried out to assess the increase in yield potential of winter wheat in the U.K. due to variety improvement since the early years of this century. The effects of other genetic changes were minimized by applying fungicide to control eyespot and foliar diseases, and by using nets to prevent lodging. The experiments were carried out in 1978 at Cambridge. One, on soil of high fertility in Camp Field, received 104 kg N/ha and the other, on soil of lower fertility in Paternoster Field, received 38 kg N/ha. Twelve genotypes were tested. Eight were varieties which formed a chronological series beginning with Little Joss, introduced in 1908. The remaining genotypes were recently developed selections from the Plant Breeding Institute and a line bred by the French breeders, Benoist.

The average yield of the 12 varieties and lines tested was 3·96 t/ha in Paternoster Field and 6·40 t/ha in Camp Field. In both fields the two highest yielding entries, Hobbit and the advanced breeding line 989/10, outyielded Little Joss by close to 40%. Benoist 10483 was the only entry for which the percentage yield advantage depended on high soil fertility.

The newer, high yielding, varieties were shorter and reached anthesis earlier than the older varieties. They had lower stem weights/m2than the older varieties but similar maximum leaf area indices and leaf weights/m2. Within each experiment the total dry-matter production of the varieties was similar, the increase in grain yield due to variety improvement being associated mainly with greater harvest index (ratio of grain yield to grain + straw yield).

It is argued that by a continuation of the trend towards reduced stem length, with no change in above-ground biomass, breeders may be able to increase harvest index, from the present value of about 50% to about 60%, achieving a genetic gain in yield of some 25%. As the limit to harvest index is approached, genetic gain in yield will depend on detecting and exploiting genetic variation in biomass production.
Intake and metabolism studies with fresh and wilted silages
Authors: Morgan C. A. , Edwards R. A. , McDonald P.
Published: March 2009

Fresh and wilted silages (dry matter 169 and 359 g/kg; pH 4·00 and 5·09; lactic acid 165 and 34 g/kg D.M., respectively) were made from ryegrass and used in intake and metabolism experiments with cattle and sheep. Complete ruminant diet (CRD) was used as a control.

Voluntary dry-matter intake of the silages by wether sheep was not significantly different (70·7 and 69·1 g/kg W0·75 for fresh and wilted material, respectively) but was significantly higher (P < 0·001) for CRD (97·9 g/kg W0·76). With rumen-fistulated steers the voluntary intakes of dry matter for the fresh and wilted silages and CRD were 117·1, 105·7 and 130·4 g/kg W0·76, respectively, and were not significantly different. The digestibility of dry matter was significantly higher (P < 0·01) for the fresh and wilted silages (0·751 and 0·698, respectively) than for the CRD (0·608). When incubated in nylon bags in the rumen the silages rapidly lost nitrogen and only 0·2 and 0·3 of nitrogen of the fresh and wilted materials, respectively, remained after 1 h. Between 0·4 and 0·5 of the residual nitrogen in the silages was subsequently lost over a period of 24 h. The loss of the nitrogen of the CRD was much slower and 0·3 of the nitrogen remained after 24 h. The rate of loss of digestible cell wall constituents was similar for the fresh and wilted silages but was slower for the CRD. The silages gave similar rumen fermentation patterns (pH, total volatile fatty acids, acetic, propionic, butyric, valeric and hexanoic acids and ammonia concentrations) during the period following their consumption.

The palatability of the fresh and wilted silages, measured with rumen-fistulated sheep, was less than that of the CRD and a ruminal effect on intake was observed in the case of the silages.

The high intake of the fresh silage is noteworthy, as it casts grave doubt on the widely held view that fermentation acids, particularly lactate, are pre-eminent in governing the voluntary intakes of silages.

From the rapid loss of nitrogen from the silages in nylon bags in the rumen it is concluded that, to increase the utilization of nitrogen, it would be advantageous to reduce protein breakdown in the silo and to supplement silage with a readily available energy source.
Colonization of lateral, seminal and adventitious roots of wheat by the take-all fungus, Gaeumannomyces graminis var. tritici
Authors: Gilligan C. A.
Published: March 2009

Progressive colonization of adventitious, seminal and lateral roots of wheat by Gaeumannomyces graminis var. triticiwas monitored for 18 days after direct inoculation of roots. Adventitious roots supported greater colonization by superficial runner hyphae above and below inoculation sites than did seminal roots due to more rapid establishment of colonization. Subsequent rates of superficial runner hyphal growth along the two types of root were not significantly different. In contrast with seminal and lateral roots, adventitious roots did not show any dark stelar discoloration during the period of observation. Both the rate of growth of superficial runner hyphae and of advance of dark stelar discoloration were substantially slower on lateral roots than on seminal roots. After an initial period of equal growth above and below inoculation sites, superficial runner hyphae grew more slowly below than above these sites on all three types of root.
The effects of various deacetylation procedures on the nylon bag digestibility of barley straw and of grass cell walls recovered from sheep faeces
Authors: Bacon J. S. D. , Gordon A. H.
Published: March 2009

Two poorly digested materials, barley straw and grass cell wall residues recovered from sheep faeces, were treated with sodium ethoxide, methoxide or hydroxide under various conditions and the effects on their digestibilities studied by the nylon bag technique in the sheep rumen.

Acetyl groups were removed during these treatments and the degree of deacetylation could be controlled by adjusting the amounts of reagents used, about 25 m-mole of base/g being required to produce the maximum effect. Sodium ethoxide in ethanol was the least effective of the reagents used: it did not remove acetyl groups from barley straw and left a larger proportion untouched in faeces cell walls than did sodium methoxide in methanol.

Irrespective of the reagent employed digestibility increased with the progress of deacetylation and the two processes reached a maximum together, but there was not a linear relation between acetyl content and digestibility. In the case of straw treated with sodium hydroxide there appeared to be a linear relationship between digestibility and the amount of reagent applied, up to 20 m-moles/g straw.

Phenolic ester groups were less susceptible to the reagents tested than acetyl groups. It is concluded that the action of the basic reagents is probably upon polysaccharides other than cellulose, that access to some regions of the cell walls may be limited by the solvent present, and that the linkages that restrict digestibility have a sensitivity to basic reagents similar to that of the acetyl ester groups present.
Boron requirement and deficiency symptoms of fenugreek (Trigonella foenum–graecum) as shown in a water culture experiment with inoculation of Rhizobium
Authors: Mølgaard P. , Hardman R.
Published: March 2009

This experiment was made to determine the possible reason for deficiency symptoms seen on fenugreek (Trigonella foenum-graecum) in field trials during the dry summer of 1976. Using rockwool cubes for root support, it was shown that symptoms seen in the field plants resulted from boron deficiency.

The symptoms of boron deficiency in fenugreek are described and illustrated. The main symptoms were failure offloweringor fertilization, decreased apical growth, small crisped leaves in a terminal rosette and a gradual yellowing of the lower leaves. In combination with low nitrogen, the boron-deficient plants had yellow, succulent leaves at a very early stage. High calcium and high nitrogen increased the demand for boron.

Inoculation with Rhizobium meliloti of plants with a low nitrogen supply was performed with success. The bacteria formed healthy, pink nodules on the roots inside the rockwool cubes.

The lowest content of boron in whole plants showing boron deficiency symptoms (no pods formed) was 13 μg/g and in this respect fenugreek is very similar to lucerne (Medicago sativa), a plant known to have a high boron requirement. Fenugreek has a high tolerance of excess boron.
The significance of damage during imbibition to the field emergence of pea (Pisum sativum L.) seeds
Authors: Powell Alison A. , Matthews S.
Published: March 2009

Differences in the field emergence of seed lots of vining peas were shown to be largely due to differences in the sensitivity of seeds to imbibition damage caused by the rapid uptake of water. The reduced emergence seen for all lots in wet soil resulted from a faster rate of water uptake and a consequent increase in imbibition damage. This caused both physiological death of low vigour seed lots and enhanced predisposition to pre-emergence mortality in unsterilized soil in all lots. The potential for the chemical protection of seeds against rapid water uptake is discussed.
The effect of temperature on cold hardening ofLoliutn perenneseedlings
Authors: Fuller M. P. , Eagles C. F.
Published: March 2009

The variation in hardening responses under different temperature regimes for three cultivars ofLolium perenneL. is described. The relative cold hardiness of the cultivars was modified by different temperatures during hardening. A threshold temperature existed above which hardening did not occur, but this temperature varied between cultivars.

Although continuous low temperatures (2 °C) favoured hardening, hardening also occurred under warm day and cool night conditions (15:2 °C) where cultivars showed contrasting hardiness responses in daylengths of 16, 12 and 8 h. Under some of these conditions both leaf growth and hardiness were possible.

The significance of these results is discussed in terms of the development of screening techniques and breeding objectives.
Carcass Composition of Foetal Lambs: Effects of Hypophysectomy and Pituitary Stalk-Section
Authors: Broad T. E. , Davies A. S. , Liggins G. C.
Published: March 2009

Besides retarding somatic development, hypophysectomy markedly increases the deposition of subcutaneous fat in foetal lambs (Liggins & Kennedy, 1968). Two hypophysectomized (HX) and two pituitary stalk-sectioned (SX) foetuses became available for dissection during a study of the growth of normal Romney sheep (Broad & Davies, 1980a, b and unpublished). The present report supplements the existing information concerning the effects of altered hypophyseal function on the carcass composition of foetal lambs (Liggins & Kennedy, 1968; Alexander, 1978).