Showing papers in "The Journal of Agricultural Science in 1978"
TL;DR: In this paper, the authors measured absorbed radiation and leaf area indices of wheat and barley crops and showed that throughout most of growth the fraction of absorbed solar radiation could be described by a simple exponential equation.
Abstract: Analysis of measurements of absorbed radiation and leaf area indices of wheat and barley crops showed that throughout most of growth the fraction of absorbed solar radiation could be described by a simple exponential equation.For several of these crops grown under a wide range of weather and husbandry at Sutton Bonington and Rothamsted, 2-weekly values of crop growth rate (C) were closely related to radiation absorbed until ear emergence and about 3·0 g of dry matter (D.M.) were produced by each MJ of photosynthetically active radiation (PAR) absorbed. Final crop weight was closelyrelated to total PAR absorbed during growth (SA); on average about 2·2 g D.M. were produced per MJ absorbed, equivalent to a growth efficiency (Eg) of approximately 3·9%. Unfertilized and drought-stressed crops had a smaller Eg.The fraction of total crop D.M. harvested as grain (harvest index) varied more for wheat than for barley. Calculations of a maximum realizable grain yield made using the largest values of Eg and SA for the crops measured and assuming a harvestindex of 0.53 (achieved in an experimental crop) showed a grain D.M. yield of 10·3 t D.M./ha to be possible. To achieve such a yield would require full crop cover from the beginning of April until the end of July in a typical English growing season.
539 citations
TL;DR: In this article, the root root length and root dry weight with depth and time were investigated for a commercially grown crop of Maris Huntsman winter wheat and root growth was reported.
Abstract: The production of root axes and the growth of the root system are reported for a commercially grown crop of Maris Huntsman winter wheat. Soil cores were extracted on 17 occasions during the growing season permitting a detailed study of root length and root dry weight with depth and time.Production of seminal root axes was complete by the beginning of March when all plants possessed six (occasionally seven) axes which persisted throughout the life of the crop. Nodal axes were produced continuously from mid-February until late May and finally numbered approximately 20 stem nodal axes per main stem. Total root dry weight increased exponentially until the beginning of April and then almost linearly to reach a maximum of 105 g root/m2 field in mid-June (anthesis). After anthesis, total root dry weight decreased but root growth continued below 80 cm. From April onwards, approximately 65% of the total root dry weight was in the 0–30 cm layer.
294 citations
TL;DR: In this paper, a study of the fractionation of nitrogen isotopes in the diet by cattle is described and the results discussed, and it is argued that the use of natural 15N as a tracer in grazed ecosystems is more complicated than was at first thought.
Abstract: A study of the fractionation of nitrogen isotopes in the diet by cattle is described and the results discussed.Compared with the diet, urine had a lower ratio of 15N to 14N, but faeces, blood and milk all had a higher ratio.It is argued that the use of natural 15N as a tracer in grazed ecosystems is more complicated than was at first thought.
292 citations
TL;DR: There was an orderly shift from acid-sensitive to more acid-tolerant species, particularly amongst the lactate-utilizers in response to the gradual decrease in the ruminal pH, allowing the ciliate protozoa to proliferate and regain control of the fermentation.
Abstract: A stepwise adaptation was carried out on eight sheep through diets containing 10, 24, 44, 60 to a final diet containing 71% maize meal and molasses. The numbers of protozoa in the rumen increased in proportion to amount of readily fermentable carbohydrate fed, up to and including the 60% grain and molasses diet, while the numbers of total culturable bacteria remained essentially constant. However, the proportions of amylolytic and lactate-utilizing bacteria increased, and there was an orderly shift from acid-sensitive to more acid-tolerant species, particularly amongst the lactate-utilizers in response to the gradual decrease in the ruminal pH. Up to this stage the protozoa probably controlled the rate of fermentation by engulfing starch grains and bacteria and were thus able to maintain the pH of the rumen above 5·5. Lactic acid appeared only transiently and the peak values tended to diminish as adptation progressed.The first day the final diet was fed the ruminal pH decreased to 5·4 or below for several hours. Within 7 days the number of protozoa had decreased by 50–80% and the number of total culturable bacteria increased sharply. Conditions in the rumen became unstable: peak values of D- and L- laotic acid increased by ca. 0·5 HIM, the acetate/propionate ratio decreased to ca. 2 and peak glucose concentration increased t o 3·2–9·5 mM. One animal refused all food for 1 day. Acid-tolerant species of lactate-utilizing bacteria multiplied rapidly in response to the increased production of ruminal lactic acid and the ratio of amylolytics to lactate-utilizers decreased from a mean of 10·7 to 3·6. This controlled the increase in lactic acid and the decrease in ruminal pH, allowing the ciliate protozoa to proliferate and regain control of the fermentation.The types of cellulolytic bacteria did not change during the experiment. Despite their acid sensitivity, the number of cellulolytic bacteria per gram of ingesta was of the same order after 54 days on the 71% grain and molasses diet (0·5–13·3 × 107) as on the initial high roughage diet (3·2–7·6 × 107).Three sheep which bloated showed no marked chemical or microbiological differences from the non-bloating animals.
233 citations
TL;DR: In this article, a series of resolvable incomplete block designs suitable for variety trials with any number of varieties v in the range 20 ≤v ≤ 100 were presented, which are not necessarily optimal in the sense of having smallest possible variances but their efficiencies are known to be high.
Abstract: In this paper we present a series of resolvable incomplete block designs suitable for variety trials with any number of varieties v in the range 20 ≤v ≤ 100. These designs usefully supplement existing square and rectangular lattices. They are not necessarily optimal in the sense of having smallest possible variances but their efficiencies are known to be high.
147 citations
TL;DR: In this paper, the effect of drought on the harvest yield and its components, on water use and nutrient uptake, was investigated, and it was shown that a prolonged early drought had an exceptionally large effect on both yield and water use.
Abstract: Automatic mobile shelters were used to keep rain off a barley crop in a drought experiment. The treatments ranged from no water during the growing season to regular weekly irrigation. This paper reports the effect of drought on the harvest yield and its components, on water use and nutrient uptake.Drought caused large decreases in yield, and affected each component of the grain yield. The magnitude of each component varied by up to 25% between treatments, and much of the variation could be accounted for by linear regression against the mean soil water deficit in one of three periods. For the number of grains per ear, the relevant period included tillering and ear formation; for the number of ears per unit ground area, the period included stem extension and tiller death; for grain mass, the period included grain filling.The harvest yields were linearly related to water use, with no indication of a critical period of drought sensitivity. The relation of grain yield to the maximum potential soil water deficit did show that a prolonged early drought had an exceptionally large effect on both yield and water use.Two unsheltered irrigation experiments, also on barley, were made in the same year on a nearby site. The effects of drought on yield in these experiments were in good agreement with the effects observed on the mobile shelter site.When fully irrigated, the small plots under the mobile shelters used water 11% faster than larger areas of crop, because of advection. The maximum depth from which water was extracted was unaffected by the drought treatment. When 50% of the available soil water had been used the uptake rate decreased, but the maximum depth of uptake continued to increase.Measurements of crop nutrients at harvest showed that nitrogen uptake was large, because of site history, and that phosphate uptake was decreased by drought to such an extent that phosphate shortage may have limited yield.
122 citations
TL;DR: Summary supplements of protected soya-bean–tallow were incorporated into a hay–concentrate diet and fed ad libitum to Friesian cows during the first 13 weeks of lactation and true digestibilities of organic matter, carbohydrate, protein, non-fatty-acid lipid, total energy, calcium, magnesium and phosphorus were unaffected by the amount of supplement given, whereas fibre digestibility was reduced by increasing the supplement.
Abstract: supplements of protected soya-bean–tallow were incorporated at 0, 1·7, 3·0 or 5·0 kg/day into a hay–concentrate diet and fed ad libitum to Friesian cows during the first 13 weeks of lactation.Intakes of supplement during weeks 1–6 were 0,1·34, 2·25 and 3·18 kg/day and during weeks 7–13, 0, 1·64, 3·10 and 4·24 kg/day on each of the respective treatments.As the lipid supplement increased there was a reduced intake of hay and concentrates, giving rise to reduced intakes of total, protein, and particularly ‘carbohydrate’ (non-protein, non-fatty-acid) energy. Apparent digestibilities, particularly of fibre, decreased as fatty-acid intake increased. After correcting for endogenous losses, true digestibilities of organic matter, carbohydrate, protein, non-fatty-acid lipid, total energy, calcium, magnesium and phosphorus were unaffected by the amount of supplement given, whereas fibre digestibility was reduced by increasing the supplement. Fatty acid digestibility was little affected up to an intake of 1·4 kg/day but above this there was a sharp reduction.Yields of milk, milk energy, protein, fat and lactose were increased at low lipid supplementation but reduced at the highest supplementation when amounts of protein and carbohydrate digested were lowest.Lipid supplementation reduced concentrations of rumen total volatile fatty acids in association with reduced, proportions of butyrate and. increased proportions of propionat. Plasma β-hydroxybutyrate and magnesium were reduced and plasma free fatty acids increased in cows given lipid supplemented diets.There were no differences between treatments in plasma glucose, lactate or calcium nor in live-weight changes.
107 citations
TL;DR: In this article, the results of 80 calorimetric experiments with sheep and cattle, mostly conducted in Scotland, were analysed using a generalization of the Mitscherlich equation R = B(lexp(pG))-l, where R is daily energy retention and G daily gross energy intake, both scaled by dividing by the fasting metabolism.
Abstract: The results of 80 calorimetric experiments with sheep and cattle, mostly conducted in Scotland, were analysed using a generalization of the Mitscherlich equation R = B(l–exp(–pG))–l, where R is daily energy retention and G daily gross energy intake, both scaled by dividing by the fasting metabolism. The relations between gross energy and metabolizable energy were also examined. Methods of fitting the Mitscherlich equation and the errors associated with it are presented.It is shown that the gross energy of the organic matter of feed can be estimated from proximate principles with an error of ±2·3% (coefficient of variation) and that provided different classes of feed are distinguished, the metabolizable energy of organic matter can be estimated from gross energy and crude fibre content with an error of ±6·9%. Parameters of the primary equation made with cattle agreed with those made with sheep and there was no evidence of non-proportionality of responses on substitution of feeds in mixtures.The efficiency of utilization of gross energy for maintenance and for body gain of energy was related to the metabolizability of gross energy and, in addition, to fibre or to protein content. Prediction equations are presented which describe these relationships.It is shown that the primary equation can be manipulated to express a number of biological concepts and that its two parameters B and p can be simply derived from estimates of the two efficiency terms for maintenance and production.The results are discussed in relation to the design of feeding systems for ruminant animals and to the derivation of optima in their feeding.
103 citations
TL;DR: Results indicate that improved N nutrition enables the later-developing tillers to survive and produce ears more competitively.
Abstract: This research was conducted to determine the effects of applying N-fertilizer to standard and semidwarf spring wheat varieties on the components of grain yield, and especially on the ability of tillers to develop and produce ears under semiarid conditions. For two growing seasons at Mandan, North Dakota, tillers were identified and tagged according to the leaf axil from which they originated. The survival and development of these tillers, identified as M, T1, T2, and T3 for main stem and tillers from axils of first, second and third true leaves respectively, were observed and measured from emergence to maturity. N-fertilizer was applied at 0, 50 and 270 kg N/ha annually, representing deficient, adequate and excessive N supply.N-fertilizer application increased grain yield of both varieties, with the increase between 50 and 270 kg N/ha being significant for the standard variety only. Most of this response to N resulted from an increase in the number of ears/ha, arising from reduced mortality of tillers, particularly T2 and T3 tillers during the latter part of the season when water was limited. For a given variety, grain production by M and by T1 tillers was seldom affected by N treatment. Although data were analysed by several means, all results indicate that improved N nutrition enables the later-developing tillers to survive and produce ears more competitively. Final grain yield was closely correlated with N content of a given tiller at the tillering stage, and to dry weight of individual tillers at both tillering and heading. Order of tiller had no appreciable effect on N content of grain. The proportion of final grain yield originating from M decreased from about 60% without N to about 36% for 270 kg N/ha, primarily because of increased survival and production from T2 and T3 tillers following the application of N-fertilizer.
100 citations
TL;DR: In this article, a cow with rumen and simple duodenal cannulas was given diets of hay and dairy cubes, which led to small diurnal variations in inorganic P-32P specific activity but at similar daily sampling times the 32P-specific activity reached a steady state after dosing for about 4 days.
Abstract: Young steers with rumen and simple duodenal cannulas were given diets of approximately equal amounts of flaked maize and hay (A) or of flaked maize and straw supplemented with decorticated groundnut meal (DCGM) (B), fishmeal (C), heated soya-bean meal (D) or raw soya-bean meal (E) or of dried grass (F). A cow with rumen and re-entrant duodenal cannulas was given diets of hay and dairy cubes.Some steers received doses of 32P-labelled inorganic phosphate twice daily with their concentrate feed. This led to small diurnal variations in inorganic P–32P specific activity but at similar daily sampling times the 32P specific activity in rumen bacterial nucleic acids reached a steady state after dosing for about 4 days. Contributions of microbial-N to non-ammonia-N (NA-N) entering the duodenum were then estimated by comparing nucleic acid 32P/NA-N ratios in related samples of rumen bacteria and duodenal contents. Similar estimates were made in these and other animals using α-, e-diaminopimelic acid (DAP) and ribonucleic acid (RNA) as bacterial markers.Estimates for steers given diets A, B, C and F based upon ‘32P-labelled RNA nucleotides’ were, on average, 85% of those based upon total RNA. The differences were attributed mainly to the latter being elevated by the presence of small amounts of dietary RNA. When RNA-based estimates of the proportion of microbial-N in NA-N in duodenal contents for these and other steers which were nearly free of protozoa were multiplied by 0·85 (‘adjusted RNA’) the values were, on average, similar to those based upon DAP. Similar estimates for the cow based upon ‘adjusted RNA’ measurements were, however, about twice those based upon DAP, probably because the cow contained a high protozoal population and the DAP based, method did not account for protozoal N.For some steers total flows at the duodenum of organic matter (OM), microbial-N (mean based upon ‘adjusted RNA’ and DAP) and residual food N were estimated by reference to chromic oxide. Average values for g microbial-N synthesized/kg OM truly digested in the rumen for the different diets ranged from 15 to 22 (mean 20). Mean degradabilities of food N (residual food N at duodenum/N intake) were 0·57, 0·71, 0·71, 0·70 and 0·84 for diets A, B, C, D and E respectively. No differences between diets were significant at P < 0·05.
94 citations
TL;DR: In this article, the authors measured volumetric soil water content and soil water potential under a winter wheat crop during the 1975 growing season and found that the importance of a few deep roots in taking up water during a dry season is emphasized.
Abstract: Volumetric soil water content and soil water potential were measured beneath a winter wheat crop during the 1975 growing season Almost no rain fell between mid-May and mid-July and the soil dried continuously until the potential was less than – 20 bars to a depth of 80 cm Evaporation was separated from drainage by denning an ‘effective rooting depth’ at which the hydraulic gradient was zeroRates of water uptake per unit length of root (inflow) were calculated for the whole soil profile and for individual soil layers Generally, inflow decreased throughout the period of measurement from a maximum of 2·5 × 10–3 to a minimum of 0·66 × 10–3 ml water/cm root/day Values in individual layers were frequently higher than the mean inflow and the importance of a few deep roots in taking up water during a dry season is emphasized A similar correlation between inflow and soil water potential was found to apply for the 0–30 cm and 30–60 cm layers during the period of continual soil drying This relationship represents the maximum inflow measured at a given soil water potential; actual inflow at any particular time depends upon the interrelationship of atmospheric demand, soil water potential and the distribution of root length in the soil
TL;DR: The mixed buffer salts of artificial saliva were incorporated at three rates: 0, 5·7 and 11·4% in pelleted diets prepared from 60% ground flaked maize and 40% dried ground grass.
Abstract: The mixed buffer salts of artificial saliva were incorporated at three rates: 0 (diet 1), 5·7 (diet 2) and 11·4% (diet 3) (w/w) in pelleted diets prepared from60% ground flaked maize and 40% dried ground grass. The control and mineral-supplemented diets were fed to sheep hourly (Expt 1) or twice daily (Expt 2).When the sheep were fed hourly or twice daily the pattern of fermentation in the rumen was altered from a predominantly propionate to mainly acetate fermentation. Dilution rate in the rumen increased from 0·036 to 0·053 to 0·064 when diets 1, 2 and 3 were fed hourly, and dilution rate was negatively related to the molar proportion of propionic acid (P < 0·05) and positively related (P < 0·05) to the molar proportion of acetic acid in rumen fluid, but these relationships were not apparent in Expt 2.Nitrogen retention was higher for lambs fed diet 2 than for those fed diets 1 and 3 (P < 0·05) in Expt 1.In sheep fed hourly, selenomonads and bacteroides were the predominant rumen bacteria associated with the control diet but the inclusion of mineral salts resulted in the bacteroides being replaced by large number of chain-forming cocci. Numbers of protozoa were variable. The relationship of these changes to the fermentation pattern is discussed. In sheep fed twice daily there was much variation between animals.
TL;DR: During the early period of infestation of winter rape, pollen beetles and seed weevils were mainly feeding and attaining sexual maturity, with some loss of seed weight and viability when feeding on pods of spring rape.
Abstract: During the early period of infestation of winter rape, pollen beetles and seed weevils were mainly feeding and attaining sexual maturity. Before a crop flowered pollen beetles fed on buds but only some of those which they had perforated to obtain pollen dropped off. When flowering started adults obtained pollen from flowers rather than from buds. They laid their eggs in the buds but not in the flowers. Larvae moved from flower to flower up the raceme and caused no damage. Probably many podless stalks have been wrongly attributed to pollen beetle damage.Overwintered seed weevils caused no damage by feeding on rape pods. New generation seed weevils caused some loss of seed weight and viability when feeding on pods of spring rape; this is probably unimportant on a field scale.Pollen beetles and seed weevils mated from mid-May until the emergence of new generation adults; these did not mate before hibernating.
TL;DR: A standard method is proposed for establishing the seasonal pattern of production for grasses by recording the yield from grass swards cut every 4 weeks and from which limitations to growth from the supply of water or nutrients have been removed.
Abstract: A standard method is proposed for establishing the seasonal pattern of production for grasses. The procedure consists in recording the yield from grass swards cut every 4 weeks and from which limitations to growth from the supply of water or nutrients have been removed. Four series of plots are harvested in rotation, spaced a week apart so that there is a routine of harvesting a constant number of plots on the same day each week. A statistical analysis is also described enabling comparisons to be made between the grasses under test. An example is given to illustrate the method and the results obtained.
TL;DR: In this article, two sheep, with and without ciliate protozoa, were fed on a wood-pulp cellulose, corn starch, soya-bean protein diet and the microbiological and chemical characteristics of the rumen ingesta of both sheep were studied.
Abstract: Two sheep, with and without ciliate protozoa, were fed on a wood-pulp cellulose, corn starch, soya-bean protein diet and the microbiological and chemical characteristics of the rumen ingesta of both sheep were studied. The purified diet led to a simplified rumen flora enabling some deductions to be made about the interactions of the principal bacterial species and their interactions with the protozoa in relationship to the biochemical analysis of the rumen. Ammonia concentrations were similarly low in each animal. Total volatile fatty acid concentrations were higher in the faunated sheep though the proportion of propionic acid was highest in the unfaunated sheep. Cellulose digestion in the faunated rumen was about twice that in the unfaunated one. Total bacterial concentrations in the unfaunated rumen were over twice those in the faunated rumen, but the numbers of cellulolytic bacteria were higher in the latter while the numbers of amylolytic bacteria were higher in the unfaunated rumen. The principal species of bacteria differed in the two rumens.
TL;DR: It may be that well-adapted two-row and six-row genotypes have patterns of development balanced for the particular ear type, and hybridization between ear types may disrupt these balanced developmental patterns producing a high frequency of poorly adapted genotypes in the progeny.
Abstract: Leaf and tiller production, ear development and ear growth were measured on a two-row and a six-row spring barley genotype, on the F1 between them and on the first backcrosses.Among the developmental differences between the parental genotypes the following appeared to be of particular significance: the two-row genotype bore more leaves on the main shoot than the six-row genotype and these were initiated more slowly, but emerged more rapidly; the two-row genotype had a proportionately longer ear initiation phase than the six-row; the apical dome was bigger in the six-row than in t he tworow; the two-row genotype produced more tillers.The association of characteristics with ear type may depend on a pleiotropic effect of the ear type (V – v) locus or, alternatively, some of these characteristics may be under independent genetic control. The latter hypothesis was supported by the developmental pattern of the F1.It may be that well-adapted two-row and six-row genotypes have patterns of development balanced for the particular ear type. Hybridization between ear types may disrupt these balanced developmental patterns producing a high frequency of poorly adapted genotypes in the progeny.
TL;DR: Soil erosion in a field in north Norfolk is described in this article, where the authors discuss the soil, slope, cultural and rainfall factors which caused erosion and a solution to the problem is suggested.
Abstract: Soil erosion in a field in north Norfolk is described. Gullies formed, one up to 2 m deep, 5 m wide and 214 m long, and from this gully about 450 t of soil was eroded. Other gullies and rills deposited about 275 t of soil. In the large (61 ha) field the area subject to erosion was small, about 2·5%. The soil, slope, cultural and rainfall factors which caused erosion are discussed. Erosion in this field is not a rare phenomenon and crop yields will be affected if erosion continues. A solution to the problem is suggested.
TL;DR: The behavioural responses to a ram, of ewe lambs experiencing oestrus for the first and second times, showed many signs of inadequacy by comparison with those of mature ewes, indicating failure of some aspects of the courtship sequences which are required to sustain and reinforce the ram's interest.
Abstract: Observations were made on mating behaviour and reproductive performance during the puberal period in 61 well-grown Perendale (Cheviot × Romney) ewe lambs. In four animals, the first oestrus (as indicated by raddle marks) was not accompanied by ovulation, and three other lambs, though marked by the rams, were not inseminated.The behavioural responses to a ram, of ewe lambs experiencing oestrus for the first and second times, showed many signs of inadequacy by comparison with those of mature ewes. Individual ewe lambs and mature ewes in oestrus were exposed to a ram in a pen for 3 h, and their responses were ranked on a scale of 1 (full adult response) to 5 (weak response). Of mature ewes 95% scored 1, compared with only 27% of ewe lambs. Across the lambs 59% scored 3 or more, indicating failure of some aspects of the courtship sequences which are required to sustain and reinforce the ram's interest. In a paddock-mating system many lambs showed a strong tendency to disassociate themselves from the rams after each courtship and mating sequence. Consequently there was little evidence of harem formation. Fifty-six per cent of services came in the first 2 h of oestrus, only 14% after the 6th hour and none after the 11th hour.Duration of the first oestrus in lambs was 18·4 h compared with 29·3 h in mature ewes. Mating the 61 ewe lambs over the first three cycles after puberty resulted in 38 of them being pregnant with 46 foetuses at autopsy in mid to late pregnancy. The success rate did not differ between cycles.
TL;DR: The digestion of the carbohydrate and protein components of the two diets was investigated, using sheep fitted with re-entrant cannulae at the proximal duodenum and terminal ileum and consuming daily 950 g of herbage dry matter, leading to a more efficient fermentation in the rumen.
Abstract: S 24 perennial ryegrass harvested in June, and subsequently in September from the same sward was conserved by rapid freezing The digestion of the carbohydrate and protein components of the two diets was investigated, using sheep fitted with re-entrant cannulae at the proximal duodenum and terminal ileum and consuming daily 950 g of herbage dry matterThe higher content of soluble carbohydrate and the lower content of protein in the spring-cut herbage compared with the autumn cut, led to a more efficient fermentation in the rumen with a higher yield of volatile fatty acids per mole of substrate degraded, a proportionately higher yield of propionic acid and a substantially greater net gain of protein between mouth and duodenum on the spring cut herbage Consequently, the quantity and composition of the amino acids entering the small intestine, or being absorbed therein, were not significantly different, despite the higher protein content noted on the autumn herbageThe total energy absorbed was markedly higher for the spring herbage (11·2 MJ/kg DM) compared with the autumn herbage (9·5) and the energy absorbed as protein from the two diets comprised 20 and 26% of total energy absorbed respectivelyThe possible causal mechanisms within the rumen, and the subsequent effect of these on nutrient supply are discussed in relation to the well-established higher efficiency of use of metabolizable energy (ME) of spring-cut herbage compared with autumn cut herbage of similar apparent energy digestibility
TL;DR: It is suggested that the dangers implicit in these rates of fat loss must be taken into consideration when deciding on dietary regimes and the timing of breeding cycles for highly prolific ewes, or indeed when embarking on a programme of increased prolificacy.
Abstract: Seventy-eight Finnish Landrace × Dorset Horn ewes in lamb to Suffolk rams were slaughtered serially between 50 and 145 days of gestation. The mean litter size was 2·7. The daily feeding regime aimed to provide each ewe with 15 MJ of metabolizable energy (ME) in the first month of gestation and 9·4 MJ in the second and third. Thereafter the ewes were provided with a basal intake of either 9·6 MJ (low plane, LP) or 13·4 MJ (high plane, HP) plus 1·3 MJ for each foetus.For ewes with 2, 3 and 4 foetuses the mean percentage changes in maternal body weight over pregnancy were respectively — 5, — 10 and — 14 (LP) or + 3, — 2 and — 6 (HP). Changes in weights of blood, liver and the empty gastro-intestinal tract through gestation varied with the plane of nutrition but not with number of foetuses. In contrast, udder weight at parturition was dependent on number of foetuses but not on plane of nutrition.Increased hydration of the maternal tissues in late pregnancy tended to mask concurrent losses of body fat. For example, over the last 2 months, HP ewes carrying quadruplets lost on average 1·0 kg in body weight but 5·5 kg of (chemically determined) fat. The latter was lost at a rate which increased up to an average of 170 g/day over the last 2 weeks of pregnancy. Net changes in body protein were estimated to be relatively small, but there was some redistribution, including loss from muscle and gain by the udder. There was no evidence of any demineralization of the maternal skeleton.The practical significance of the changes in body composition is discussed, in particular that of the increasing rates of loss of body fat with increasing litter size. It is suggested that the dangers implicit in these rates of fat loss must be taken into consideration when deciding on dietary regimes and the timing of breeding cycles for highly prolific ewes, or indeed when embarking on a programme of increased prolificacy.
TL;DR: Inadequate pollination probably limits yield in self-fertile cultivars of swede rape that auto-pollinate poorly and in turnip rape cultivars that are nearly self-sterile.
Abstract: The pollination requirements of eight cultivars of swede rape (Brassica napus) and two of turnip rape (Brassica campestris) grown in a glasshouse, were compared Cultivars differed in the number of pods, and of seeds per pod set by auto-pollination Cultivars of turnip rape yielded more when cross-pollinated than when self-pollinated by hand but those of swede rape did not, although additional pollination of swede rape increased the set of early flowers Inadequate pollination probably limits yield in self-fertile cultivars of swede rape that auto-pollinate poorly and in turnip rape cultivars that are nearly self-sterile
TL;DR: In this paper, the different responses to urea supplementation of treated and untreated barley straw are discussed in relation to a new system of estimating protein requirements for ruminants put forward by the Agricultural Research Council.
Abstract: Milled barley straw, either untreated or treated with 70 g of NaOH/kg straw was supplemented with four levels of urea, namely 0, 6, 12 or 18 g/kg and fed ad libitum to young sheep. For the untreated straw, dry-matter intakes were (g/day) 423, 451, 441 and 463, while the digestibility of organic matter was 458, 467, 490 and 483 g/kg, respectively. For the treated straw, the intakes of dry matter were 355, 402, 531 and 567 g/day and the digestibility of organic matter was 423, 480, 589 and 628 g/kg respectively.The different responses to urea supplementation of treated and untreated straw are discussed in relation to a new system of estimating protein requirements for ruminants put forward by the Agricultural Research Council.
TL;DR: Nitrogen decreased dry weight per grain, especially of the semi-dwarf varieties, and the year 1976 was exceptionallydry and nitrogen had only small effects in that it affected neither straw dry weight nor number of ears but slightly increased grain yield by increasing the number of spikelets and number of grains per spikelet.
Abstract: Eight amounts of nitrogen ranging from 0 to 210 kg N/ha were applied to two tall and one semi-dwarf variety of winter wheat in the spring of 1975 and 1976 The tall varieties were Cappelle-Desprez and Maris Huntsman; the semi-dwarf variety was Maris Fundin in 1975 and Hobbit in 1976 Interactions between varieties and nitrogen were few and small compared with the main effects All varieties produced their maximum grain yields with 180 kg N/ha The yield of the semi-dwarf varieties, but not the others, decreased slightly with more nitrogen Cappelle-Desprez yielded less grain than the other varieties in both years In 1975 the yields of Maris Fundin and Maris Huntsman were similar and in 1976 Hobbit yielded more than Maris Huntsman The varieties had similar numbers of ears at maturity and similar patterns of tillering The semi-dwarf varieties had most grains per spikelet, and hence grains per ear, and Cappelle-Desprez had least The semi-dwarf varieties had the smallest grains The semi-dwarf varieties had less straw than the other varieties and hence the largest ratios of grain to total above-ground dry weight The decrease in dry weight of stem and leaves between anthesis and maturity was similar for all varieties In 1975 the efficiency of the top two leaves plus top internode in producing grain was the same for all varieties, but in 1976 Hobbit was more efficient than the other two There were some small differences between varieties in nutrient uptake that were not related to differences in growth Maris Fundin tended to have a greater phosphorus and potassium content than the tall varieties Hobbit contained slightly less nitrogen than the tall varieties at maturity, and had a smaller concentration of nitrogen in the grain Applying 210 kg N/ha doubled grain yield in 1975 Applying nitrogen resulted in a largeincrease in number of ears and a small increase in number of grains per ear due to the development of more fertile spikelets per ear Nitrogen decreased dry weight per grain, especially of the semi-dwarf varieties With extra nitrogen, straw dry weight at maturity, shoot dry weight atanthesis and leaf area were all increased relatively more than grain yield, and stems lost moredry weight between anthesis and maturity than without nitrogen The year 1976 was exceptionallydry and nitrogen had only small effects in that it affected neither straw dry weight nor numberof ears but slightly increased grain yield by increasing the number of spikelets and number of grains per spikelet It also increased leaf area proportionately to grain yield In 1975 nitrogen increased evaporation of water from the crop before anthesis but decreased it after anthesis, even though it continued to increase the extraction of water from below 90 cm
TL;DR: Barley following barley suffered severely from take-all disease (Gaeumannomyces graminis var. tritici); barley after other crops was little affected; other recognized soil-borne diseases were unimportant.
Abstract: Two experiments compared yields of spring barley following barley, oats, beans (Vicia faba), red clover (cut) and (one experiment only) oil-seed rape, and tested effects of trefoil (Medicago lupulina) undersown in the preliminary crops of barley and oats. N fertilizer was applied at two rates to preliminary crops, and four rates to the final crop in each experiment. Barley following barley suffered severely from take-all disease (Gaeumannomyces graminis var. tritici); barley after other crops was little affected. Other recognized soil-borne diseases were unimportant. Barley yielded less after barley than after other crops except where excessive N fertilizer caused lodging. Clover and beans left N residues equivalent to about 88 and 44 kg fertilizer N/ha respectively; undersown trefoil left inconsistent N residues. Couchgrass (Agropyron repens) was more prevalent after barley than after other crops.
TL;DR: In this article, a dry-block and auto-analyser system for protein nitrogen estimation in plant material has been proposed, which is suitable for several crop species of widely different protein content, only field bean seeds required longer digestion time.
Abstract: Summary A dry-block digestion system suitable for the estimation of total protein nitrogen in plant material has been evaluated. The method was found to be as accurate as Kjeldahl flask digestion, required much less fume cupboard space and enabled samples to be dealt with in large batches through weighing, digestion and analysis. The batch size can be designed to be compatible with the autoanalyser capacity. These advantages result in more rapid analysis with less chance of errors and accidents. A 45 min digestion period was found suitable for several crop species of widely different protein content, only field bean seeds required longer digestion time. Using the technique described samples are digested at a relatively low temperature (330 °C) for a short time and digests do not solidify on cooling. The autoanalyser method for determining ammonia concentrations in barley and malt digests (Micheson & Stowell, 1970) has been slightly modified for use with the plant materials studied. The dry-block and autoanalyser system is rapid, precise and compact, requires small amounts of tissue and is suited to the routine analysis of breeding material.
TL;DR: In this article, the authors used sponges impregnated with 30 mg SC-9880 (G. D. Searle) or intramuscularly with 100 μg Cloprostenol (I.C.I. 80, 996) and examined subsequently for oestrus, ovulation and fertilization.
Abstract: Mature cyclic ewes were treated intravaginally with sponges impregnated with 30 mg SC-9880 (G. D. Searle) or intramuscularly with 100 μg Cloprostenol (I.C.I. 80, 996) and examined subsequently for oestrus, ovulation and fertilization. At 70 h after the end of treatment, 90% of ewes treated with SC-9880 and 45% of those treated with Cloprostenol had ovulated. Of ewes yielding eggs at 100 h a significantly higher proportion of SC-9880 treated sheep showed evidence of fertilization (69% v . 7%).
TL;DR: The internal organs and blood contained significantly lower concentrations of crude protein, ash, Ca, Mg and P but significantly higher concentrations of Cu and Fe.
Abstract: The amino acid, mineral and collagen composition of certain different components of the bodies of preruminant calves was determined. The amino acid composition (g/kg crude protein) of the empty bodies of preruminant calves was: hydroxyproline, 40; aspartic acid, 81; threonine, 40; serine, 44; glutamic acid, 129; proline, 81; glycine, 113; alanine, 71; cystine, 13; valine, 39; methionine, 17; isoleucine, 28; leucine, 69; tyrosine, 25; phenylalanine, 36; lysine, 64; histidine, 25; arginine, 70; tryptophan, 8. The hydroxyproline, proline and glycine contents were much higher than in bovine muscle because about one-third of the total protein of the calves was collagen, a protein particularly rich in these amino acids. The collagen content of the individual body components varied considerably as did their amino acid contents. There were also some marked differences in the contents of some of the major constituents and minerals in the individual components. In particular the internal organs and blood (component (6)) contained significantly lower concentrations of crude protein, ash, Ca, Mg and P but significantly higher concentrations of Cu and Fe.
TL;DR: Attaching bags with nylon cord to a weight was a better method than enclosing them in perforated jars in the rumen which restricted digestion, although frozen extrusa was digested more than oven-dried feed, especially in samples of Heteropogon contortus.
Abstract: Factors affecting the nylon-bag technique, for examination of digestion in the rumen of extrusa and hay samples of low nutritional value, were studied. Effects of: the method of placement of bags in the rumen; saliva in extrusa; drying and milling techniques; a second-stage digestion with acid-pepsin solution; sample size; and losses of particulate matter through bag cloth were studied. Digestion of dry matter (d.m.) and cell walls after 12, 24, 48, 72 and 168 h in the rumen were used to indicate treatment effects.Attaching bags with nylon cord to a weight was a better method than enclosing them in perforated jars in the rumen which restricted digestion. Drying technique had little effect on digestion, although frozen extrusa was digested more than oven-dried feed, especially in samples of Heteropogon contortus. Chewing of forage was sufficient to obtain maximum rates of digestion. Milling extrusa through 1 or 2 mm screens did not increase digestion. An extra period of digestion in acid-pepsin solution increased digestion of feed samples more than that of extrusa, but the effects were small. It reduced between-bag variation slightly, but did not alter the significance of differences between treatments. The effect of sample size on digestion was small. Sample weight (3, 6 and 9 g) was kept proportional (42 mg/cm2) to bag cloth area.Digestion of d.m. after 24 h reflected digestion of cell walls. Digestion of cell walls was faster in grasses than in legumes. The higher digestibility of legumes was due to solubilization within 24 h of the greater amounts of cell contents found in legumes. Cell contents were only partially solubilized, and up to 10 g per 100 g original d.m. were not removed. Losses of particulate matter averaged 4·6% (range 0·5–10·6%). Losses were high when samples were finely milled (1 mm screen) but varied between species. Pore aperture of cloth was 25 μm. Methods for determining loss and correction of digestion data for such losses are given.
TL;DR: In this paper, a field experiment was made to determine water uptake patterns of soya beans and water use and to compare relative effectiveness of roots at various depths in the profile, and the maximum rate of uptake of the deep roots was greater, per unit of length, than shallow roots.
Abstract: A field experiment was made to determine water uptake patterns of soya beans and water use and to compare relative effectiveness of roots at various depths in the profile.Depth of water extraction by the root systems increased with rooting depth. Water uptake rates decreased with soil water content at all soil depths and the soil water content at which roots extracted almost no water increased with depth. The maximum rate of uptake of the deep roots was greater, per unit of length, than shallow roots.
TL;DR: In this paper, the composition of the body of young pigs was examined by slaughter and chemical analysis, and the results showed that after removal from the sow, the lipid content of the empty body decreased from about 15 to 7·6%, and in subsequent 4 weeks had recovered only slightly to between 7·7 and 10·9%.
Abstract: Four experiments with 133 piglets of between 21 and 55 days of age were used to examine, by slaughter and chemical analysis, the composition of the body of young pigs. Following removal from the sow, the lipid content of the empty body decreased from about 15 to 7·6%, and in the subsequent 4 weeks had recovered only slightly to between 7·7 and 10·9%; with the exception of pigs with a particularly high intake of energy whose 42-day lipid content had increased to 13·2%. Where Y3 was the lipid gain, X1 the digestible energy intake (MJ) and X2 the ratio of digestible energy to digestible crude protein (g), over all experiments Y3 = 7·83X1 + 4945X2−1260. There was little change in the protein content of pigs consequent upon the effects of either removal from the sow, pig age, diet type or nutrient intake. Over all experiments and slaughter weights; P = 0·164W−100, where P was the protein content of the body (g) and W the empty body weight (g). The efficiencies of conversion of digestible energy to energy gain in body protein and lipid were 0·36 and 0·33 respectively, associated with a constant (daily maintenance) term of 0·462 MJ ME/kg LW0·75. The low value for lipid is as would be expected for animals catabolizing lipid within the experimental period.