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Showing papers in "The Journal of Agricultural Science in 1988"


Journal ArticleDOI
TL;DR: It is indicated that inoculation with Azospirillum can lead to yield increases in dryland grain sorghum, primarily through improved utilization of soil moisture.
Abstract: SUMMARY The effect of inoculation with Azospirillum brasilense on growth, water status and yield of dryland sorghum (cv. RS 610 and cv. H-226) growing on stored soil moisture was examined in three field experiments conducted during the years 1983-5. Plants were sampled at regular intervals, and the following characteristics were measured: dry-matter accumulation, leaf area, grain yield, percentage nitrogen and phosphorus in leaves, leaf water potential, canopy temperature, transpiration, stomatal conductance and soil water depletion. Inoculation led to an average increase of 19% in total stover dry-matter yield, as a result of higher rates of dry-matter accumulation during the early stages of growth. Azospirillum inoculation caused a 15-18% increase in grain yield in all three experiments. This increase was associated with a greater number of seeds per panicle. The water regime of sorghum plants was improved by inoculation, as seen in their higher leaf water potential, lower canopy temperatures and greater stomatal conductance and transpiration. Total extraction of soil moisture by inoculated plants was greater (by about 15%) and occurred from deeper soil layers, compared with non-inoculated controls. These findings indicate that inoculation with Azospirillum can lead to yield increases in dryland grain sorghum, primarily through improved utilization of soil moisture.

132 citations


Journal ArticleDOI
TL;DR: Avalon winter wheat was grown in 1983 on a light-textured, sandy loam (Cottenham series) which had a subsoil pan with a maximum dry bulk density of 1·8 g/cm3 at 35 cm depth as mentioned in this paper.
Abstract: Avalon winter wheat was grown in 1983 on a light-textured, sandy loam (Cottenham series) which had a subsoil pan with a maximum dry bulk density of 1·8 g/cm3 at 35 cm depth. This was destroyed on part of the site with a ‘Wye Double Digger’ so that crop growth in panned and pan-free soils could be compared. The interaction of the pan with soil water supply was studied by sheltering the crops during May, June and July and either withholding water completely or irrigating weekly back to field capacity.The pan had a major effect on the vertical extension rate of the root system as monitored both by coring and from observation tubes. Roots were largely confined above the pan until March, but compensatory growth occurred within this soil layer and the total length of root was unaffected. At anthesis, roots had reached a maximum depth of 100 cm in the panned soil compared with 140 cm in the pan-free soil.Early shoot growth and N content were substantially reduced by the pan because of the inaccessibility of mineral N in the subsoil. However, both the growth of the crop and N uptake recovered following top dressings of N fertilizer and, when water was not limiting, the pan had a negligible effect on grain yield.Root and shoot growth were reduced by the fixed shelter, but the imposed drought did ot affect water use by the crops until after anthesis when the root systems were already fully developed. Without irrigation, the crop growing on the double-dug soil yielded 5% more than that growing on the panned soil, but there was no evidence for extra water use from the subsoil by the former crop. The best treatment (double-dug with irrigation) outyielded the worst (panned soil with drought) by 8%.

127 citations


Journal ArticleDOI
TL;DR: It was demonstrated that acetic acid bacteria can be responsible for the onset of aerobic deterioration of maize silage and by monitoring the development of the microbiota of samples exposed to air, acetic Acid bacteria and yeasts often developed simultaneously in uninoculated silage samples exposure to air.
Abstract: Acetic acid bacteria were isolated from maize silages and from samples of maize silage exposed to air. The isolates apparently belonged to the genus Acetobacter. By inoculating maize silage with strains of acetic acid bacteria isolated from silage and by monitoring the development of the microbiota of samples exposed to air it was demonstrated that acetic acid bacteria can be responsible for the onset of aerobic deterioration of maize silage. However, acetic acid bacteria and yeasts often developed simultaneously in uninoculated silage samples exposed to air. In all experiments ethanol was oxidized to acetic acid followed by a rapid oxidation of lactic and acetic acids when ethanol was depleted.

120 citations


Journal ArticleDOI
TL;DR: In this article, the ability of three internal markers to predict dry matter digestibility and two external markers to estimate faecal output was evaluated in a completely random design to evaluate the ability for the three internal marker estimates and external marker estimates.
Abstract: Twenty fine-wool, ruminally cannulated lambs (average weight 45–9 kg) were used in a completely random design to evaluate the ability of three internal markers to predict dry matter digestibility and two external markers to estimate faecal output. Lambs were allotted randomly to one of four diets: 100% prairie hay (PH), 100% lucerne hay (LH), 50% prairie hay:50% sorghum grain (PS) and 50% lucerne hay: 50% sorghum grain (LS). The trial consisted of a 14-day adaptation period followed by a 7-day total faecal collection period. Feed and faecal samples were subjected to 96 h ruminal fluid and 48 h acid-pepsin digestions, followed by extraction with acid detergent (IVADF) or neutral detergent (IVNDF) solution. Dry matter digestibility (DMD) calculated from feed:faeces ratios of IVADF, IVNDF and acid detergent lignin (ADL) was compared with in vivoapparent digestibility. Ytterbium-labelled forage (YLF) and dysprosium-labelled faeces (DLF) were pulse-dosed via ruminal cannulae, and faecal Yb and Dy excretion curves were fitted to a one-compartment, agedependent model for estimation of faecal output, paniculate passage rate (PPR) and mean gastrointestinal retention time. In vivoDMD in lambs fed PH was greater (P 005) from marker estimates. In vivoDMD for lambs fed PS did not differ from IVNDF or IVADF estimates but was greater than (P 005) were observed in recovery among the three internal markers for any of the diets. Faecal output for lambs fed PH did not differ {P >005) from marker estimates but was overestimated by 15 to 20% by YLF and DLF. Faecal output for lambs fed LH was similar to the estimate from YLF, but less than (P <0–05) the estimate with DLF. For lambs fed PS, faecal output did not differ from marker estimates, but YLF and DLF values were 16% lower and 17% higher, respectively. No significant differences were observed in actual and estimated faecal output for lambs fed the LS diet. Estimates of PPR with DLF were numerically greater than YLF estimates for all diets except LS. Correspondingly, mean gastrointestinal retention time was less (P <005) for DLF compared with YLF for all diets except LS.

86 citations


Journal ArticleDOI
TL;DR: Comparison with other studies suggests that the processes outlined in this report may be common to white clover growth under grazing over a wide range of favourable environments.
Abstract: There has been little study on the growth and morphology of individual plants constituting the population of white clover in mixed swards under grazing. Such information is required if the mechanisms governing plant productivity and persistence are to be understood.Intact white clover plants were sampled from intensively sheep-grazed pastures under set stocking, rotational grazing, and a combination of both systems, by taking turves (250 × 250 mm), and washing out the plants, every month for a year. Characters measured for every stolon of each plant were: presence of a growing point; numbers of leaves, roots and axillary buds; stolon length. Total plant leaf and stolon dry weight were also recorded. Plants were classified according to degree of branching, and the contribution of each branching order to the population determined.There were strong seasonal variations in plant size (leaf and stolon dry weight, stolon length, and numbers of stolons and leaves per plant) which showed a significant decrease in spring with recovery over the following summer. This was paralleled by a rapid increase in the proportion of less branched plants (1st and 2nd branching order) in the population from 60 to 80% in spring, as higher-order plants broke up into smaller- and lower-ordered plants at this time. Numbers of roots per plant increased over winter to peak in early spring then declined in the following summer-autumn. While system of grazing management had no significant effect on branching structure of plants, it had a large effect on plant dry weight; rotationally grazed plants were 2·5 times larger than set stocked plants (0·182 cf. 0·073 g respectively).Other general features of plant morphology were that each successive order of branch stolons was shorter and length before branching was less than that of their preceding parent stolon. The highest branching order observed was 6th order. There was no relationship between branching and numbers of roots; in branched plants only 55% of stolons were rooted regardless of plant order, but rooted stolons accounted for 85% of total stolon length and carried 62, 48 and 90% of the leaves, growing points and axillary buds per plant, respectively.Comparison with other studies suggests that the processes outlined in this report may be common to white clover growth under grazing over a wide range of favourable environments.

85 citations


Journal ArticleDOI
TL;DR: In this article, the percentage of incident photosynthetically active radiation reaching the ground was measured in winter wheat crops throughout the season, and related to projected area index (L) of leaves, plus sheaths and stems when present.
Abstract: The percentage (P) of incident photosynthetically active radiation (PAR) reaching the ground was measured in winter wheat crops throughout the season, and related to projected area index (L) of leaves, plus sheaths and stems when present. Between unfolding of the first leaf and appearance of the flag leaf the mean value for the exponential extinction coefficient (K) was 0·46±0·007. The value did not vary with the growth stage of the wheat and was scarcely affected by experimental treatments, apart from effects resulting from the presence of senescent tissues that intercepted light but whose area was not included in L. After anthesis, in crops having between 340 and 540 ears/m2, between 68 and 89% of incident PAR penetrated to below the ears. Relation between the further penetration to the base of the crop canopy and the area of green plus senescent leaf and stem tissue gave K = 0·50. The relation did not change significantly between anthesis and complete senescence.The relation between P and L was similar whether P was obtained from instantaneous measurements made near midday, 24 h integrals of PAR or percentage ground cover measured photographically.

64 citations


Journal ArticleDOI
TL;DR: Autumn sowings produced heavier pods and beans due to both a faster rate and a longer duration of growth which were associated with a greater production of assimilate during the seed growth period and Seed growth depends on both the current assimilate and stored reserves, the latter especially when plants were subjected to environmental stress.
Abstract: The growth and yield of four crops of field bean cv. Maris Bead in response to irrigation and sowing date were analysed in relation to leaf area expansion and senescence and their absorption and utilization of photosynthetically active radiation (PAR). Total dry matter (D.M.) production and seed yield were strongly correlated with total green area duration (GAD) and post-flowering GAD respectively.Total D.M. production was also strongly related to radiation absorbed by the green surfaces of the crop although autumn sowing and drought both decreased the constant of proportionality, i.e. the growth efficiency (Eg). Autumn sowings yielded more than spring sowings because they grew for longer and received 22% more radiation. Their harvest index was also about 40% higher than in spring sowings. These more than compensated for their smaller Eg. Drought decreased yield mainly by decreasing radiation received and Eg. Growth duration was shorter and harvest index was smaller.The rate of phenological development was strongly dependent upon temperature and to a lesser extent on photoperiod. The average thermal duration from emergence to flowering was 790 °Cd above a base of 0 °C. The time from sowing to the end of the pod growth was well represented by a simple multiplicative model in which development rate was a linear function of temperature above a base of 0 °C and photoperiod above a base of 6 h. The average photothermal duration required for 10 crops was 980 °Cd.An attempt was also made to determine the crop physiological and environmental factors which govern the change in size of the yield components of field bean crops caused by irrigation and sowing date. The final number of pods per plant was closely correlated with the rate of supply of assimilates during pod filling. Irrigation increased assimilate flux by increasing leaf area, growth rate and total dry matter during pod growth. Both the rate and duration of pod growth were little affected by irrigation. Autumn sowings produced heavier pods and beans due to both a faster rate and a longer duration of growth which were associated with a greater production of assimilate during the seed growth period. Seed growth depends on both the current assimilate and stored reserves, the latter especially when plants were subjected to environmental stress.

63 citations


Journal ArticleDOI
TL;DR: Progeny of perennial ryegrass plants selected for low and high leaf shear strength were sown in a spaced-plant field experiment and were shown to differ in leaf strength in the same direction, confirming this to be a heritable trait.
Abstract: Progeny of perennial ryegrass (PRG) plants selected for low and high leaf shear strength were sown in a spaced-plant field experiment and were shown to differ in leaf strength in the same direction, confirming this to be a heritable trait. Selection for low leaf shear strength also reduced weight per leaf length, but had no effect on dry-matter (D.M.) percentage, growth score, rust score or tendency towards aftermath heading.Rates of D.M. consumption (g D.M./min) and ruminal degradation of D.M. using the polyester bag technique, were then determined with small quantities of the two PRG selection lines, and also white clover, using sheep fed a basal diet of fresh ryegrass/white clover pasture. Selecting PRG for low leaf shear strength slightly reduced concentrations of cellulose and hemicellulose, slightly increased total N concentration and increased rate of D.M. consumption by sheep (17%) but had no effect on rates of ruminal D.M. degradation. The selection thus moved the nutritional characteristics of PRG in the direction of white clover.The first nutritional response to the selection appears to be a faster rate of D.M. consumption, and it is considered that leaf shear strength has potential for selecting PRG with increased rates of voluntary intake by ruminants.

59 citations


Journal ArticleDOI
TL;DR: It was concluded that the superiority of.
Abstract: Gorse (Ulex europaeus) was harvested in late spring, summer, autumn and winter and fed to six goats kept individually in metabolism cages for 21-day periods. The same gorse was also fed to sheep during the first two periods, but not in autumn and winter, as the hardness and sharpness of the needles caused total rejection by the sheep at these times. Measurements of voluntary intake and apparent digestibility were made over the last 7 days of each period. To minimize effect of diet selection the animals were fed at hourly intervals. Dietary lignin concentration was very high, ranging from 170 to 200g/kg D.M. Voluntary metabolizable energy (ME) intake for goats was respectively 1·60, 0·82, 0·72 and 0·41 times maintenance for the four harvesting times, late spring, summer, autumn and winter. Corresponding values for sheep were 0·90 and 0·33 for gorse harvested in late spring and summer. Thus, in late spring and summer, voluntary ME intake by goats was respectively 1·8 and 2·5 times that of sheep. The reduction in ME intake with time was attributed to increases in the contents of D.M. and of lignin + hemicellulose in depressing voluntary D.M. intake and apparent digestibility respectively. Voluntary intake of both supplementary water and total water per unit D.M. intake were consistently less for goats than sheep. From a comparison with published values, it was concluded that the superiority of. goats over temperate breeds of sheep in digestible dry matter intake (DDMI)/kg W0·75 per day increased as the lignin content of the diet exceeded 120 g/kg D.M., indicating that goats must possess some superior mechanism for breaking down highly lignified diets such as gorse and willow. It is proposed that cashmere fibre production from goats grazing gorse for a 7-month period of each year should be evaluated as an alternative to regulating gorse with chemicals.

57 citations


Journal ArticleDOI
TL;DR: The salt tolerance limit of muskmelon was found to be associated with soil ECe value of about 5·20–6·32 dS/m, and Hara Madhu had the highest rate of yield drop per unit salinity increase.
Abstract: The salt tolerance of five muskmelon (Cucumis melo L.) cultivars Hara Madhu, Punjab Sunhari, Punjab Hybrid, Pusa Madhuras and Durgapur Madhu was assessed in field plots artificially salinized with NaCl and CaCl2. Percentage germination and melon yield of all the cultivars decreased linearly with increasing soil salinity. Decline in percentage germination with increasing salinity differed with cultivar. If soil salinity exceeded 1·11 dS/m, mean germination of muskmelon decreased at a rate of 9% per unit increase in soil salinity. Similarly melon yield decreased at a rate of 8·73% for each unit of EC exceeding 103 dS/m. Hara Madhu had the highest rate of yield drop per unit salinity increase. The salt tolerance limit of muskmelon was found to be associated with soil ECe value of about 5·20–6·32 dS/m.

54 citations


Journal ArticleDOI
TL;DR: Despite a constant and adequate Ca intake, the rate and efficiency of Ca absorption, which was low on the low-P diet, increased significantly on the adequate and high-P diets, showing that Ca metabolism can be controlled according to P status.
Abstract: Calves were fed continuously at 4 h intervals a low P basal diet with or without P supplementation to give three levels of dietary P intake: one was deficient in P (2·5 g/day), the second adequate (6·0 g/day) and the third contained an excess of P (10·0 g/ day) according to Agricultural Research Council (1980) recommendations. Once steadystate conditions were achieved (after 2–3 weeks on the diet) 32P and 46Ca kinetic studies were carried out, together with measurements of P flow rates at the reticulorumen and P and Ca balances. With increased dietary P intake, the amount of dietary P absorbed increased as initially did the efficiency of P absorption. Both the serum P concentration and the rate of P retention increased in direct relation to increased P intake and increased P absorption. Salivary secretion of P increased with increased P absorption and in direct relation to serum P concentration. Endogenous faecal losses of P were also directly related to P intake and P absorption and results suggest that increased loss with increased P intake is inevitable.Despite a constant and adequate Ca intake, the rate and efficiency of Ca absorption, which was low on the low-P diet, increased significantly on the adequate and high-P diets. Similarly, Ca retention increased substantially on the higher P diets, showing that Ca metabolism can be controlled according to P status.

Journal ArticleDOI
TL;DR: The effects of mixed infection on feed intake and body-weight gain were multiplicative and there was no interaction between infections in effect on deposition of Ca or P in the body, both species having significant effect.
Abstract: Ninety 4-month-old wether lambs were allocated to an initial slaughter group (n =10) or to one cell (n= 5) of a 4 × 4 factorial treatment design involving four levels of infection with Ostertagia circumcincta (0, 1000, 2000 and 4000 larvae/day) and Trichostrongyluscolubriformis (0, 1000, 2000 and 3000 larvae/day) They were maintained indoors in individual pens and offered freshly cut ryegrass-white clover herbage during an 84-day period of infection after which they were slaughtered Body protein, fat, water, Ca and P contents were determined Feed digestibility was determined in all sheep during 5-day periods during weeks 2, 5, 8 and 11 Faecal egg counts were determined and blood samples obtained at intervals and total worm counts done at slaughterThe effects of mixed infection on feed intake and body-weight gain were multiplicative Mean DM intake of sheep infected simply with 3000 larvae of T colubriformis or with 4000 larvae of O circtimcincta was reduced by 10 and 8% respectively, but in those infected simultaneously intake was reduced by 30% Energy retention was depressed mainly by reduction in gross efficiency of use of metabolizable energy in infections with T colubriformisand by reduction in feed intake in infections with O circumcincta The additional effect of mixed infection occurred mainly through further depression in feed intakeThere was no interaction between infections in effect on deposition of Ca or P in the body, both species having significant effect Infection with T colubriformis caused hypophosphataemia and hypocalcaemia, but infection with O circumcincta had no effectThe number of worms established by the infections was generally low compared with previous studies with conserved and concentrate feeds This was associated with relatively low pathogenicity in infection with O circumcincta and normal pathogenicity with T colubriformisInfection with T colubriformis reduced the number of adult worms of O circumcincta present at slaughter

Journal ArticleDOI
TL;DR: Improved management compared with traditional practices common in northern Syria for growing field bean, chickpea, lentil, peas, peas and vetch was shown to increase significantly the crop nitrogen uptake and subsequent protein yields in either hay, grain or straw.
Abstract: Improved management compared with traditional practices common in northern Syria for growing field bean (Vicia faba L.), chickpea (Cicer arietinum), lentil (Lens culinaris), peas (Pisum sativum) and vetch (Vicia sativa) was shown to increase significantly (P < 0·001) the crop nitrogen (N) uptake and subsequent protein yields in either hay, grain or straw. This intervention more than doubled N uptake in 1982–3 when averaged over crops and locations increasing from 31·8 kg N/ha under traditional management to 68·7 kg N/ha under improved management. Improved management also increased the proportion of nitrogen uptake that was derived from symbiotic nitrogen fixation by the crop from 55 to 69%. The treatments which gave improved crop N uptake were application of phosphate fertilizer, reduced row spacing and control of weeds. Seed inoculation with rhizobia had little or no effect on N uptake or on the proportion of N that was fixed biologically by the crop. Environmental effects on productivity, as expressed by seasonal and locational differences, were as, or more, important than management-imposed effects.Differences in N uptake by barley, following either a legume crop or barley, indicated that the residual effects of the legume crop amounted to approximately 10 kg N/ha. This represents a substantial contribution to the N nutrition of a barley crop in the dry areas of northern Syria.

Journal ArticleDOI
TL;DR: In this paper, green manuring in situ with sunnhemp (Crotalaria juncea) and dhaincha (Sesbania aculeata) significantly improved growth and yield of transplanted rice.
Abstract: Green manuring in situ with sunnhemp (Crotalaria juncea) and dhaincha (Sesbania aculeata) significantly improved growth and yield of transplanted rice. Giving the green manure crops 15 kg N/ha or 15 kg N and 30 kg P2O5/ha further increased yield. Interaction between green manuring and N fertilizer revealed that a considerable quantity of fertilizer N (45–60 kg N/ha) applied to rice could be replaced by incorporation of green manure crops to which a small amount of fertilizer had been applied. Residual fertility in terms of organic carbon and available N, P and K increased under green manuring, whereas N fertilizer made no impact on fertility build up. Grain yield of wheat and gram increased when grown after rice in plots which had grown green manure.

Journal ArticleDOI
TL;DR: Lactating females had significantly higher FOMO and DMI than non-l lactating females when compared across genotypes during early lactation on all pastures, but estimates of organic-matter digestibility, nitrogen content and pasture composition indicated large differences in pasture quality.
Abstract: Faecal output of 287 beef cows consisting of Hereford (H × H), Simmental × Hereford (S × H), Friesian × Hereford (F × H) and Brahman × Hereford (B × H) breeding was estimated using controlled release of chromic oxide (Cr2O3). All cows were from 6 to 10 years of age and had grazed on one of three pasture systems in the subtropics of New South Wales since they were 7–8 months of age. These pastures were designated as being of high, medium and low nutritive value. Faecal organic matter output (FOMO) was estimated in each of four periods (early lactation, mid lactation, late lactation, and non-lactating) during one annual production cycle.Herbage mass exceeded 2 t/ha on all pasture systems, but estimates of organic-matter digestibility, nitrogen content and pasture composition indicated large differences in pasture quality (high > medium > low). Live weight of cows averaged 604, 488 and 393 kg live weight on the high, medium and low pastures, respectively. There were significant differences in live weight between genotypes on the medium (B × H > F × H and H × H) and low (S × H ≡ F × H ≡ B × H > H × H) pastures but not on the high pasture).FOMO and dry-matter intake (DMI) differed significantly between genotypes among lactating cows on all pasture systems. Rankings on high pastures were reasonably consistent in all periods: S × H ≡ F × H ≥ B × H ≥ H × H, as were those on low pastures, B × H ≥ S × H ≡ F × H ≥ H × H. Differences on medium pastures were significant only during mid-lactation when B × H ≡ S × H ≡ F × H > H × H. Significant differences between genotypes were observed among non-lactating cows on high pastures only, where H × H ≡ S × H ≡ F × H > B × H. Lactating females had significantly higher FOMO and DMI than non-lactating females when compared across genotypes during early lactation on all pastures.

Journal ArticleDOI
TL;DR: The results show that DHP-induced depressions in growth rate may occur in this environment when cattle graze mainly on leucaena-based pasture, and dosing with D HP-degrading bacteria will overcome this problem.
Abstract: The effect on live-weight gain from dosing cattle with rumen bacteria capable of degrading 3-hydroxy-4(l H)-pyridone (DHP) was measured on cattle grazing leucaena and native grass pastures in south-east Queensland. Dosing increased the growth rate of cattle grazing only leucaena pasture: from 0·52 kg/head per day when not dosed, to 1·03 kg/head per day when dosed, in the period 6·19 weeks after treatment. Dosing did not affect the growth rate of cattle either grazing leucaena with native pasture, or grazing only native pasture. The introduced bacteria spread naturally to untreated cattle after 19 weeks post-dosing.The response to dosing occurred when untreated cattle grazing only leucaena pasture had high urinary concentrations of DHP (maximum 0·28%) and low concentrations of serum thyroxine (< 30 nmol/1). The results show that DHP-induced depressions in growth rate may occur in this environment when cattle graze mainly on leucaena-based pasture. Dosing with DHP-degrading bacteria will overcome this problem.

Journal ArticleDOI
TL;DR: It is suggested that both the reduction in milk fat concentration and the increase in milk yield in response to reductions in the fibre content of diets may be independently related to the increased in the proportion of propionate in the rumen VFA.
Abstract: Mean digestible energy (DE) intakes of 147 cows of three parities receiving three levels of DE including one ad libitum (about 2·2, 2·6 and 3·3 multiples of maintenance (MM)) drawn from three mixed diets containing hay and 60, 75 or 90% compound were calculated.Rumen samples were taken from three-quarters of the cows at monthly intervals throughout the experiment. Molar proportions of volatile fatty acids (VFA) in the rumen were not affected by stage of lactation over the 36 weeks of the experiment. The proportion of acetic acid decreased and that of propionic acid increased with greater intakes and with higher proportions of compound in the diet. The proportion of n-butyric acid was little affected by level of intake but decreased with increasing proportions of compound. In young, non-lactating cattle given the same diets but at lower levels of intake, VFA proportions were unaffected by diet composition at intakes of about 0·7 MM but at intakes of about 1·3 MM the proportion of acetate decreased and that of propionate increased when the proportion of compound was increased from 75 to 90%.The efficiency of milk energy production in relation to DE or metabolizable energy (ME) above maintenance decreased with increasing level of intake but was little affected by the proportion of compound. Partition towards live weight increased with level of intake in early lactation but not in late lactation. It also increased with higher proportions of compound in mid and late lactation but not in early lactation.Estimates of the ME requirement for live-weight change (LWC) were in reasonable agreement with recently published standards in early lactation when live weight was decreasing, but later in lactation when live-weight gain was occurring, a much higher value was calculated which is difficult to reconcile with these standards.Rumen VFA proportions were related to dietary fibre concentration and level of intake additively. The relationship to VFA proportions was close for milk fat concentration, but less so for energy partition towards live weight and none was apparent for the efficiency of ME utilization for milk energy production. It is suggested that both the reduction in milk fat concentration and the increase in milk yield in response to reductions in the fibre content of diets may be independently related to the increase in the proportion of propionate in the rumen VFA.It is concluded that further progress in studies of the dietary factors affecting the efficiency of milk production will require measurements of nutrient uptake from the digestive tract and description of milk production and LWC in terms of their chemical composition rather than energy alone.

Journal ArticleDOI
TL;DR: In this paper, the authors compared the particle size and the number of organisms adhering to the particles to investigate the effect of particle size on gas production and lipolysis of corn oil and linoleic acid.
Abstract: Particulate fractions prepared from meadow hay, ranging in size from 0·1 to 2 mm, were incubated with rumen digesta from four cannulated Romney sheep fed the same hay. The rates of gas production, lipolysis of corn oil and hydrogenation of linoleic acid were measured.The rate of gas production per g fermentable particles (FP) was approximately 30% lower with 1–2 mm than with the 0·1–0·4 mm particles. However, per m2 surface area the rate for the larger particles was found to be approximately 600% greater.The rates of lipolysis of triacylglycerols and hydrogenation of linoleic acid were respectively 25 and 60% higher per g FP and 1100 and 1200% higher per m2 FP surface area with the 1–2 mm particulate fraction.The same hay particulate fractions were incubated with pure cultures of Ruminococcus flavefaciens, since this organism is active in both lipid metabolism and cellulose fermentation. The rate of gas production and the number of organisms adhering to the particles were determined.The effects of particle size on gas production were similar to those found when incubations were carried out with rumen digesta. Per g FP the rate was 40% lower with 1–2 mm than with 0·1–0·4 mm particles. However, per m2 surface area the rate was found to be approximately 450% greater with the former.It was further found that although the density of the bacterial population on 1–2 mm particles was 600% higher than on the 0·1–0·4 mm particles, the rate of gas production per 109 bacteria remained unchanged.We conclude that per m2 surface area fermentation, lipolysis and hydrogenation were more rapid with particles ranging from 1 to 2 than from 0·1 to 0·4 mm in size. This was due, at least in part, to microbial population density.

Journal ArticleDOI
TL;DR: It was concluded that willows grown during spring and summer could adequately be used as supplementary feed during summer droughts and that willow could be used most effectively if fed to goats, followed by deer, with sheep being the least efficient.
Abstract: Voluntary intake and apparent digestibility of tree willow (Salix matsudana Χ alba) and of osier willow (Salix viminalis) were measured with male sheep and goats and voluntary intake only with male deer. Both willow species had been selected for extremely rapid growth, and were grown in coppices on high fertility soil. In a first experiment spring primary growth of both willows was fed to sheep, goats and deer in early summer, whilst in a second experiment summer regrowth (i.e. secondary growth) of osier willow was fed to sheep and goats in autumn.Although the ratio of readily fermentable to structural carbohydrate (0·51–0·70) and total N concentration (18–24 g/kg D.M.) in primary growth of the willows was less than normally found in high quality fresh temperate forages, the values were similar to those of many dried forages normally used as supplements. Averaged over sheep and goats, voluntary intake of digestible D.M. was 22% less for osier than for tree willow, this being associated with higher concentrations of lignin (197 ν 182 g/kg D.M.) and of condensed tannin (66 ν 29 g/kg D.M.) in the osier willow. The lower digestible dry-matter intake was attributable to both lower voluntary intakes and lower digestibility of the D.M. (0·57 ν 0·64). Both voluntary intake and apparent digestibility of secondary growth willow were lower than that of primary growth.When expressed as functions of the amount required for maintenance, voluntary metabolizable energy intake of goats was approximately double that of sheep, both for primary growth (2·2 ν 1·1) and for secondary growth (1·8 ν. 0·7) willow. This was attributable to consistently higher voluntary D.M. intakes/kg W0'6 by goats, and to a trend for higher digestibility than sheep, which attained significance in Expt 2but not in Expt 1. The ratios of dry-matter intake/kg W075 per day for sheep: deer: goats fed primary growth willow were 1·0:1·5:1·9, with deer thus being intermediate between the other two species. There were no differences in voluntary intake (g/kg W0·75 per day) of sheep, goats and deer fed a high quality lucerne hay.It was concluded that willows grown during spring and summer could adequately be used as supplementary feed during summer droughts and that willow could be used most effectively if fed to goats, followed by deer, with sheep being the least efficient. Tree willow is a preferred choice to the osier willow used here, and it was further concluded that like Lotus pedunculatus, high concentrations of lignin and condensed tannin, both of which are produced by the same biochemical pathway, are likely to be limiting nutritive value of the more leafy osier willow.

Journal ArticleDOI
TL;DR: In the three experiments the seasonal pattern of permeability varied, although there was a tendency for seeds to gain permeability in autumn, and a strong suggestion that the change from impermeability to permeability was reversible.
Abstract: Three experiments which measured seed production and seed survival of annual medics (Medicago spp.) were conducted at Tel Hadya in north Syria. In Expts 1 and 2, conducted in consecutive years, the effects of rate and date of sowing on seed yield and its components were measured, while in Expt 3, the residual seed under summer grazing was monitored. In all three experiments seed permeability was observed at frequent intervals in summer and autumn. Selected ecotypes of three native medics (Medicago rigidula (L.) All., M. rotata Boiss. and M. noeana Boiss.) were compared with cultivars of M. truncatula Gaertn. and M. polymorpha (L.).Seed production was greatest at sowing rates of 20–40 kg/ha. The native species produced more seed (up to 1000 kg/ha) than the cultivars (less than 500 kg/ha), although not significantly so in the case of the late-flowering ecotype of M. noeana. Seed yields of 500–1000 kg/ha were considered to be sufficient to perpetuate the pastures, but even higher seed yields are desirable.Seed yield was closely related to number of pods in all ecotypes and, in Expt 2, up to 95% of flowers failed to produce mature pods. Flowers were more likely to mature at high sowing rate (256 kg/ha), in striking contrast to flower production itself which was greatest at sowing rates of less than 30 kg/ha. Flowers produced early in the season (before mid-April) were far more likely to give mature pods than late-produced flowers.In late October, seeds of the native species were less permeable (10%) than those of the cultivars (30%), although their permeability was similar to that of the cultivars in Australia. In the three experiments the seasonal pattern of permeability varied, although there was a tendency for seeds to gain permeability in autumn. In Expt 1 there was a strong suggestion that the change from impermeability to permeability was reversible.Ewes grazing mature pods gained weight, apparently as long as pod availability exceeded 10 kg/ha. It was clear that the condition of ewes was not a good guide to appropriate stocking rate for persistence of pastures, and that farmers will have to use other methods to assist them in grazing management.

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TL;DR: The response of field beans to irrigation applied during the vegetative, flowering and pod-filling phases was examined during 1981-2 and 1982-3 as discussed by the authors during the two seasons.
Abstract: The response of 4 crops of autumn- and spring-sown field beans cv. Maris Bead to irrigation applied during the vegetative, flowering and pod-filling phases was examined during 1981–2 and 1982–3. The crops, grown on a Templeton silt-loam, were irrigated weekly in amounts equal to the difference between the estimated evapotranspiration and rainfall of the previous week using trickle irrigation.Seed yield of fully irrigated autumn- and spring-sown crops (averaged over the two seasons), was 5·2 and 3·3 t/ha respectively, about 45% greater than the yield of unirrigated crops. The increase in yield due to irrigation was mainly associated with an increase in total dry matter (TDM) production as harvest index varied little within each sowing. The yield response to each mm of applied irrigation water ranged from 0 to 9 kg/ha and did not appear to be related in any way to the developmental phase of the crop when irrigation was applied.Seed yield within each sowing was closely correlated with the number of beans per unit area and the number of pods per plant. Autumn sowings yielded about 55% more than spring sowings mainly due to a higher harvest index which was associated with a much heavier mean weight per bean.

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TL;DR: In this paper, the authors used data from 11 sugar beet crops grown at different sites, in different years and with some variations in husbandry, to re-examine the process of dry-matter partitioning.
Abstract: Data from 11 sugar-beet crops grown at different sites, in different years and with some variations in husbandry have been used to re-examine the process of dry-matter partitioning. Two-phase linear models did not describe adequately the distribution of dry matter. There was no evidence of a discontinuity in the partitioning between root and shoot at any point in crop development. It is suggested that, contrary to a recent view, events in the shoot, rather than the storage root, largely determine how dry matter is allocated between growth and sugar storage.

Journal ArticleDOI
TL;DR: There was considerable variation in herbage and seed yields within both genotypes and environments, and G × E interactions were highly significant, but in the broad sense heritability was much higher for seed than for herbage yield.
Abstract: With the current high prices for livestock, forage legumes are increasingly attractive to farmers in west Asia There has been very little genetic improvement of the main species, of which three vetches, Vicia saliva (common vetch), V villosa subsp dasycarpa (woollypod vetch), and V narbonensis (Narbon vetch), show promise As a first step in genetic improvement 23 genotypes of common vetch and one each of woollypod vetch and Narbon vetch were grown at four sites in Syria and one in Lebanon over three seasons Since local climatic conditions were considered to be of considerable importance, each site in each year was treated as a separate environment, to give 15 environments in all genotype × environment (G × E) interactions were analysed using linear regressionThere was considerable variation in herbage and seed yields within both genotypes and environments, and G × E interactions were highly significant In the case of herbage yield good environments could be defined as those receiving high rainfall and low incidence of frost Several genotypes appeared to possess wide adaptation, in terms of both yield and stability Climate, except for late spring rains, had little effect on seed yield, nor were any of the genotypes widely adapted However, in the broad sense heritability was much higher for seed than for herbage yieldThere is a need to define good and bad environments for seed yield Based on observations during the study it is likely that good environments for Narbon vetch are those where broomrape (Orobanche crenata) is absent, while root-knot nematode (Meloidogyne artiella) may affect seed yield of common vetch In view of its high seed yield the possible role of Narbon vetch as a grain legume is briefly discussed

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TL;DR: In this paper, the acid additive, formic acid, the sterilant, formaldehyde, the oxidative enzyme, glucose oxidase, and the starch hydrolysing enzyme complex, Termamyl, were used to extract cellulose, hemicelluloses, lignin and phenolic acids.
Abstract: Laboratory silos were prepared from lucerne (Medicago sativa)which had been treated with a number of chemical and biological additives. The additives used were the acid additive, formic acid, the sterilant, formaldehyde, the oxidative enzyme, glucose oxidase, and the starch hydrolysing enzyme complex, Termamyl. Silos were prepared in duplicate and pairs of each treatment were opened at 0, 2, 9, 20 and 60 days ensilage. The pH, volatile fatty acid patterns and dry-matter yields were determined and the composition of the residual fibre was determined for cellulose, hemicelluloses, lignin and phenolic acids. The only treatment to enhance the rate of fall in pH was formic acid. The rate of decline in pH of the silages treated with glucose oxidase was not significantly different from the other treatments. The starch degrading enzyme complex did enhance the loss of starch from the lucerne but it did not appear to have any significant effect on the silage characteristics measured. No loss of true lignin was observed from the fibre but most of the phenolic acids present were removed. All the treatments appeared to have a significant effect on the cellulose content which was in contrast to earlier work on ryegrass silages where no effect was observed. On the other hand, the treatments had less effect on the hemicellulose fraction than was observed in the previous work with ryegrass. These results can be explained by differences in the structures of the fibres from lucerne and ryegrass.

Journal ArticleDOI
TL;DR: Reduction of faecal P excretion in group 2 appeared to enable P homoeostasis even at the reduced level of P intake, and the amounts of P and Ca secreted in milk during P deficiency in group 3 clearly exceeded the corresponding net absorptions.
Abstract: In weeks 1–6 of lactation, 11 goats were fed diets adequate in phosphorus content, supplying a basal intake of 2·8 g P/day plus 1·4 g P/kg milk produced. In group 1 (three goats), this scheme was continued until week 16. In group 2 (four goats), P supply was changed from an adequate one to a reduced amount by restricting the variable intake to 1·0 g P/kg milk during weeks 7–16 and the basal intake to 0·8 g P/day during weeks 12–16. In group 3 (four goats), P deficiency was caused during weeks 7–11 by a basal intake of 0·8 g P/day plus only 0·4 g P/kg milk. During weeks 12–16 these goats received the same supply of P provided in weeks 1–6.Milk yield was depressed in group 3, but not in group 2. Composition of milk was not affected by P intake in either group. Digestibility of organic matter was reduced from 0·73 to 0·64 by P deficiency treatment. Reduction of faecal P excretion in group 2 appeared to enable P homoeostasis even at the reduced level of P intake. The amounts of P and Ca secreted in milk during P deficiency in group 3 clearly exceeded the corresponding net absorptions. During this period, daily faecal P excretion was reduced to 17 mg/kg live weight. P concentrations in blood plasma, saliva and particle-free rumen fluid were also drastically reduced. Faecal excretion of P increased after the animals returned to the diet supplying adequate P. The increase occurred before the pre-depletion P status had been restored.

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TL;DR: Two scries of simulation experiments were used to investigate the accuracy of treatment and variance estimation with a neighbour analysis of field trials proposed by Gleeson & Cullis (1987) and illustrated that treatment effects were consistently estimated more accurately by the REML neighbour (RN) analysis than by incomplete block (IB) analysis with recovery of interblock information.
Abstract: Two scries of simulation experiments were used to investigate the accuracy of treatment and variance estimation with a neighbour analysis of field trials proposed by Gleeson & Cullis (1987). The first series examined the accuracy of residual maximum likelihood (REML) estimation of seven theoretical error models applicable to field trials. REML estimation provided accurate estimates of the variance parameters, but the Ftest of treatments was slightly biased upward (to +2·4%) for first differences models and slightly biased downwards (to –1·4%) for second differences models. The second series of simulations, based on 19 uniformity data sets, illustrated that treatment effects were consistently estimated more accurately by the REML neighbour (RN) analysis of Gleeson & Cullis (1987) than by incomplete block (IB) analysis with recovery of interblock information. The relative gain in accuracy of RN over IB depends on the amount of systematic variation or ‘trend’ in the trial, and ranged from 6 to 18% with an average of 12% for a range of trend and error variances commonly encountered in field trials. The predicted average standard errors of pairwise treatment differences from the RN analysis were in close agreement with their empirical estimates, indicating that the predicted average S.E.D. is approximately valid.

Journal ArticleDOI
TL;DR: Significant factors affecting birth weight, weight at 30, 60, 90, 120, 150, 210 and 270 days of age, and preweaning growth rate were breed and sex of kid, type of birth, year–month and age of dam.
Abstract: Data on gestation period of 701 indigenous East African and Galla does and pre- and postweaning growth of 810 pure-bred and cross-bred kids were analysed by least squares statistical analysis. Breeds of kids were East African, Galla, Toggenburg × East African, Toggenburg × Galla, Anglo-Nubian × East African and Anglo-Nubian × Galla. Average gestation length was 149 days and was significantly (P < 0·05) affected by type of birth of the kid, year–month of kidding, and age of dam. Does carrying twins had shorter gestation length than does carrying singles. Sex and breed of kid did not have significant effect on gestation length.Significant (P < 0·05) factors affecting birth weight, weight at 30, 60, 90, 120, 150, 210 and 270 days of age, and preweaning growth rate were breed and sex of kid, type of birth, year–month and age of dam. Male kids grew faster and were heavier than females. Kids born single were heavier and grew faster than twin-born kids. Kids from dams less than 3 years old weighed less than kids from older dams. Cross-bred kids had higher preweaning growth rates than indigenous pure-bred kids. The Anglo-Nubian × Galla cross was heaviest while the East African ranked lowest. The results point to importance of cross-breeding with temperate breeds to increase growth rates of indigenous goats. Comparison of Toggenburg and Anglo-Nubian sires for cross-breeding showed both buck breeds produced kids with roughly equal growth rates. Evaluation of indigenous Galla and East African dams for cross-breeding showed Galla dams produced heavier kids than East African but preweaning growth rates were not significantly different.

Journal ArticleDOI
A. Petri1, H. Müschen1, G. Breves1, Otto Richter1, E. Pfeffer1 
TL;DR: In this article, five rumen-cannulated dairy goats were fed diets containing CrEDTA and (15NH4)2SO4 for weeks 1-6 of lactation.
Abstract: Summary Five rumen-cannulated dairy goats were fed diets supplying 2·8 g P/day plus 1·4 g P/kg milk (adequate P) for weeks 1–6 of lactation. Two goats then continued to receive this adequate P supply while three goats were fed deficient diets supplying only 0·8 g P/day plus 0·4 g P/kg milk. Solutions containing CrEDTA and (15NH4)2SO4 were infused into the rumen continuously for 96 h during weeks 5–6 and 11–12, respectively. At intervals following the intraruminal infusion, 15N enrichments of rumen ammonia-N, rumen bacteria-N and milk protein-N were determined. Cr concentration was measured in particle-free rumen fluid. P deficiency did not significantly affect rumen fluid kinetics. It caused a significant increase in pH and reduced the size of the rumen ammonia pool and its outflow rate. Digestibility of organic matter as well as efficiency of microbial protein synthesis were decreased significantly and thus net microbial yield was reduced from 34·1 to 13·7 g N/day. The transfer of N of microbial origin to milk protein decreased from 5·3 to 2·7 g/day, whereas secretion of N in milk protein not originating from rumen microbes remained unchanged at 5·6–5·8 g/day.

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TL;DR: In this paper, the authors studied the mineralization kinetics of nitrogen in acid soils, and their modification by the addition of an organic fertilizer (cattle slurry), by incubating a humic cambisol for 36 weeks using a method based on that of Keeney & Bremner (1967).
Abstract: The mineralization kinetics of nitrogen in acid soils, and their modification by the addition of an organic fertilizer (cattle slurry), were studied by incubating a humic cambisol for 36 weeks using a method based on that of Keeney & Bremner (1967). The cumulative curve of the quantity of nitrogen mineralized in soil not given fertilizer departs significantly from Stanford's theoretical model, which predicts linear dependence of nitrogen mineralized upon √t. The observed kinetics are interpreted as due to the superposition of two mineralization processes involving different substrates.The cumulative mineralized nitrogen curves for soil samples enriched with the various slurry fractions likewise reflect complex kinetics involving at least two main substrates. Consideration of the net mineralized nitrogen shows that F,, the solid fraction with the highest C/N ratio, clearly induced immobilization of nitrogen during the first 130 days of incubation, and analysis of the NO3/NH4 ratio suggests that this immobilization was probably at the expense of nitrate. F3, the liquid fraction, first induced a brief period of mineralization and then stabilized nitrogen levels, giving rise to a reduction in net mineralized nitrogen. The addition to the soil of F2, the semi-liquid fraction, produced results intermediate between those of the other two fractions.In conclusion, the increase in organic nitrogen in the soil after addition of cattle slurry depends in the short term on the liquid and semi-liquid fractions, whereas long-term effects involve both the stable residues of these fractions and the more solid fraction. The labile fraction of the pool of mineralizable N benefits more than the recalcitrant fraction, and the time constants of the mineralization process are reduced.

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TL;DR: It is concluded that winter shearing of the pregnant ewe results in an increased loss of maternal body tissues and metabolic adaptations to long-term cold exposure without any of the changes associated with an increase in energy expenditure during the final third of pregnancy.
Abstract: The effects of winter shearing on ewe live weight, body condition score (BCS) and the concentrations of glucose, non-esterified fatty acids (NEFA), 3-hydroxybutyrate, growth hormone (GH), cortisol, insulin and the thyroid hormones in plasma plus that of oxygen and carbon dioxide in jugular vein blood and packed cell volume (PCV) were measured at weekly intervals over the final 7 weeks of pregnancy in two groups of multiple-bearing shorn and unshorn pregnant ewes.Shorn ewes lost 47% more live weight than unshorn controls over the period from the day of being shorn to immediately after lambing. There was a significant decrease in BCS in both groups between 45 and 9 days before lambing. Three days after shearing the plasma NEFA concentration was higher in the shorn group but there were no other significant differences between shorn and unshorn groups in the plasma concentrations of NEFA, cortisol or insulin over the remaining 7 weeks of pregnancy. Both the PCV and concentration of carbon dioxide in blood were higher in shorn sheep throughout the final 6 weeks of pregnancy indicating they were making metabolic adaptations to long-term cold exposure. This response may have been mediated via an increase in thyroid hormone concentrations which were higher throughout the 7-week sampling period in shorn animals compared with unshorn controls. A decrease in ambient temperature was associated with a significant increase in the plasma concentration of GH and glucose in shorn animals. At 2 weeks before lambing there was a decrease in the plasma glucose concentration and an increase in 3-hydroxybutyrate concentration in the unshorn ewes, but these changes were not observed in the shorn animals. It is concluded that winter shearing of the pregnant ewe results in an increased loss of maternal body tissues and metabolic adaptations to long-term cold exposure without any of the changes associated with an increase in energy expenditure during the final third of pregnancy.