bluuebunny/crossref_metadata_2025 huggingface dataset:
Nitrogen metabolism in sheep. II.* The flow of amino acids into the duodenum from dietary and microbial sources
Authors: Leibholz J
Published: November 2004

Sheep were fitted with re-entrant cannulae in the duodenum and offered diets supplying 1.4, about 16, or 30 g nitrogen per day from lucerne, casein, or wheat gluten. There were two levels of metabolizable energy in the diets. The flow of α-amino nitrogen into the duodenum was less than the dietary intake for sheep on all diets except the one supplying 1.4 g nitrogen per day. The flow of most individual amino acids into the duodenum was less than the dietary intake. The flow of glutamic acid and histidine was only 14 and 15 % of the dietary intake in the sheep given 30 g nitrogen per day. However, in the sheep offered wheat gluten the flow of lysine to the duodenum was greater than the dietary intake. Some other dietary differences in amino acid concentration were reflected in the rumen and duodenal contents, but the differences were diminished. The flow of methionine and cystine into the duodenum ranged from only 3.1 to 15.8 mmoles per 24 hr. The percentage of microbial protein in the rumen and duodenal contents was estimated by the incorporation of 35S into cystine, and was found to range from 43 to 97 %. The percentage of microbial protein was inversely related to the dietary nitrogen intake and was dependent on both the dietary source of nitrogen and the intake of metabolizable energy. An average of 6.2% of the 35S continuously infused into the rumen as sulphate could be recovered at the duodenum.

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*Part I, Aust. J. Agric. Res., 23: 1059 (1972).
Selection for crude protein content in Phalaris tuberosa L. II. Field studies on selected lines
Authors: Clements RJ
Published: November 2004

Two Phalaris tuberosa lines, previously selected in a controlled environment for high or low Kjeldahl nitrogen content (percentage nitrogen, dry weight basis) in whole tillers at the heading stage, were grown in the field both as spaced plants and in swards. Herbage from spaced plants was examined for nitrogen content and for in vitro organic matter digestibility (IVDOM) at five stages during the first year of growth. Differences in percentage nitrogen between the high nitrogen and low nitrogen lines were maintained at each growth stage (vegetative, preheading, heading, anthesis, mature). At heading, the nitrogen content of whole tillers in the high nitrogen line (1.42%) was 30 % greater than that of the low nitrogen line (1.09 %), and there was considerable residual genetic variation for this character in each line. Part of the difference between the lines at this stage was due to alterations in the relative proportions of tiller components (leaf, sheath, stem, and head) which differed markedly in nitrogen concentration, and in particular to changes in the leaf/stem ratio (0.62 and 0.43 for the high and low nitrogen lines respectively). However, much of the difference was due to changes in the nitrogen content of tiller components, the high nitrogen line having consistently greater contents than the low line. The weight of whole tillers and of all tiller components was negatively related to the nitrogen content. The low nitrogen line was marginally superior in IWOM to the high nitrogen line at most growth stages, and at the mature stage was superior by 4.6 digestibility units. In swards, the two selected lines and a control (unselected) line were subjected to two defoliation frequencies (five and 10 cuts per year) and two levels of applied nitrogen fertilizer (0 and 280 kg N/ha/year, applied in the form of urea after each defoliation), commencing 3 months after sowing in the spring. Measurements of herbage yield and quality (percentage nitrogen, IVDOM) were taken during the year following commencement of treatments, and herbage yield measurements were continued for a further 8 months on the infrequently defoliated swards. Phalaris in the high nitrogen line plots had consistently higher nitrogen concentrations and lower IVDOM levels, recovered more of the nitrogen fertilizer, and showed the greatest herbage yield responses to applied nitrogen. However, over the range of treatments imposed, the low nitrogen line gave the greatest herbage yields.
Genetic variability and the application of selection indices for yield improvement in two soya bean populations
Authors: Pritchard AJ , Byth DE , Bray RA
Published: November 2004

Substantial genetic variability was found in two hybrid soya bean populations and progress in yield through selection was demonstrated. Genetic advance was restricted in those environments in which moisture stress limited the expression of genetic variation. The best F6-derived selection was 49% higher-yielding than the highest-yielding parent. However, most trials were conducted at low to moderate yield levels, and the existence of significant environmental interactions indicates the necessity for regional selection and testing. Selection indices were of greatest efficiency, relative to selection for yield alone, in those environments for which meaningful yield data were unavailable. The crosses differed substantially in the importance of different yield components in the indices. The cost of data collection for selection indices based on yield components is not justified in terms of genetic advance.
The effects of daily and weekly feeding regimes on the efficiency of energy utilization by sheep given all-wheat diets
Authors: Farrell DJ , Watson MJ
Published: November 2004

The metabolizable energy (ME) content of an all-wheat ration was similar whether given to sheep at a rate of 300 g each day or at 2100 g once each week. However, the net availability of ME was 79 % in the former group compared with 70 % in the latter, owing to the significantly (P < 0.05) higher heat production of sheep given feed once weekly. It is suggested that the increased heat production resulted from fluctuations between storage of energy and oxidation of tissue reserves associated with the extended feeding interval.
Studies of fat distribution in the bovine carcass. II. Relationship of intramuscular fat to the quantitative analysis of the skeletal musculature
Authors: Johnson ER , Pryor WJ , Butterfield RM
Published: November 2004

(1) The fat content of individual muscles of a steer was determined. (2) The intramuscular fat content of 'standard muscle groups' of Angus steers was determined and related to total dissected fat and to muscle weight distribution. (3) The partitioning of intramuscular fat among the standard muscle groups was not affected by the percentage of dissectible fat except in two small muscle groups. (4) The regressions of the weights of standard muscle groups on total muscle weight were not significantly different when calculated on muscle weights as dissected, or minus intramuscular fat content. (5) It is concluded that the differences in muscle weight distribution observed during the fattening process are due to factors other than intramuscular fat.
In vitro digestibility and carbohydrate composition of Digitaria decumbens and Setaria anceps grown at different levels of nitrogenous fertilizer
Authors: Ford CW , Williams WT
Published: November 2004

Two tropical pasture grasses, Digitaria decumbens cv. Pangola and Setaria anceps cv. Nandi, were compared on the basis of in vitro digestibility and carbohydrate composition. These species were grown at three different levels of applied nitrogen (280, 476, and 673 kg/ha) and continuously grazed at one stocking rate of 6.2 beasts per ha. The in vitro digestibility of both species apparently increased with applied nitrogen, Pangola being slightly superior at the higher nitrogen levels. Lignin did not appear to be a major factor influencing digestibility. Total extractable carbohydrates (ethanol + water-soluble) varied little with nitrogen level, although Pangola was consistently higher (c. 9.0 %) than Setaria (c. 7.2 %). Pangola had a higher total cell wall polysaccharide content than Setaria at all nitrogen levels. Numerical analysis showed a reduction in cell wall polysaccharides in both species with increasing nitrogen, this effect being more marked in Setaria. The concomitant liveweight gains showed an overall superiority in Pangola which accounted for c. 80 % of the variation in the system; a further 16% was attributable to the increased responsiveness of Setaria to applied nitrogen. Since the total cell wall polysaccharides were higher in Pangola than in Setaria, it appears that Pangola polysaccharides are more digestible than those of Setaria.
Factors limiting the intake of feed by sheep. VII. The digestion of a medium quality roughage and the effect of post-ruminal infusion of casein on its consumption by young sheep
Authors: Weston RH
Published: November 2004

Feed intake and digestion studies were conducted with sheep offered a medium quality roughage which contained, on a dry matter basis, 33.4% of acid detergent fibre and 10.3 % of crude protein. The roughage had an organic matter (OM) digestibility of 57%. The quantity of OM apparently digested in the stomach was equal to 63 % of the OM digested in the alimentary tract, and 80% of the digestion of the dietary fibre took place in the stomach. The quantity of nitrogen in forms other than ammonia that left the stomach in digesta was similar to the dietary nitrogen intake and the apparent digestibility of this digesta nitrogen in the intestines was 66%. Approximately 13 g of crude protein was digested in the intestines per 100 g digestible OM intake. The values of parameters relating to the movement of digesta through the stomach were within the ranges expected with roughage diets. The levels of essential acids in the peripheral blood plasma of sheep given the roughage ad libitum were comparatively low; the values for the total essential amino acids ranged from 85 to 105 pmoles/100 ml and varied with the time of day. The voluntary consumption of roughage by young sheep (8-9 months of age) was 66 g OM/day/(kg body eight)0.75, an intake that did not permit the animals to obtain sufficient energy to express their growth potential. Post-ruminal infusion with casein (34-39 g/day), although increasing the amount of crude protein digested in the intestines (DCP1) by about 30%, failed to increase voluntary feed consumption or rate of body growth. Accordingly voluntary feed consumption and body growth were not limited by the availability of essential amino acids at the tissue level. It was concluded that the voluntary feed consumption and rate of body growth in young sheep would not be limited by the supply of essential amino acids at the tissue level with diets providing 13 g or more of DCP1 per 100 g digestible OM-the equivalent of about 49 g DCP1/Mcal net energy.
Intestinal digestion of subterranean clover by sheep
Authors: Hogan JP
Published: November 2004

Quantitative studies have been made of digestion in the small and large intestines of sheep offered a diet of subterranean clover (Trifolium subterraneurn c.v. Clare) at levels approaching ad libitum. As in previous studies with a similar diet, most of the digestion of organic matter and of cell wall constituents occurred in the stomach; by contrast, the release of long-chain fatty acids and amino acids mainly occurred in the intestines. Although two-thirds of the dietary long-chain fatty acids were C18:2 and C 18: 3, hydrogenation in the rumen reduced their proportion to less than 20 % in the digesta leaving the stomach. The amounts of long-chain fatty acids that passed from the stomach were equivalent to about 127 % of intake. Approximately 70 % of these fatty acids were removed from the digestive tract subsequently, and most of the absorption occurred in the small intestine. The total amounts of these fatty acids absorbed from the intestines were equivalent to approximately 90% of the amount consumed, even though their apparent digestibility in the whole tract was only 61 %. Most of the nitrogen that passed from the stomach was in the form of amino acids. Of the 189 g amino acids that passed from the stomach, less than one-third reached the terminal ileum. The net losses of individual amino acids in the small intestine ranged from 66% to 84% of the amounts that passed from the stomach. It was estimated that approximately one-third of the organic matter and almost 60% of the nitrogen that passed from the stomach was present in bacterial cells. A major component of bacterial cell walls, diaminopimelic acid, was apparently not absorbed from the small intestine, though appreciable amounts of this amino acid were lost in the large intestine.
Flowering in Dactylis glomerata. I. Photoperiodic requirement
Authors: Broue P
Published: November 2004

The photoperiodic requirement for flowering of the temperate perennial grass Dactylis glomerata L. nas investigated in controlled environments. The results shoned that short day (SD) vernalization treatments are ineffectise at early stages of seedling growth and, further, that preliminary long days (LD) may enhance the effectiveness of subsequent SD vernalization. Accordingly, it is suggested that a treatment sequence of LD-SD-LD is more effective than the simpler SD-LD sequence in the promotion of flowering. These results are discussed in relation to established findings for this species.
Variation within naturally occurring Townsville stylo (Stylosanthes humilis) population; changes in population structure and some agronomic implications
Authors: Burt RL , Williams WT , Compton JF
Published: November 2004

Two populations of Townsville stylo collected from Townsville (T) (rainfall 1140 mm) and from Greenvale (G) (rainfall 640 mm) were grown in small swards at four locations (rainfall 460-869 mm) for 2 years. Phenotypic variation in the original populations and the T-derived populations from seven of the eight location-year combinations was assessed in a pot experiment. Numerical analysis of the data using an agglomerative classification delineated five distinct growth forms. The proportions of these forms differed in the original T and G populations, and the population structure of the T plots changed markedly towards that of the original G population after only one growing season at the four locations. These changes could be related to environmental conditions and weed competition. It is suggested that population heterogeneity may represent an adaptation to varying ecological and climatic conditions. Heterogeneous seed mixtures may therefore be agronomically superior to individual genotypes, and compact growth forms with high seed indices may be more suited to harsher environmental conditions.
Comparison of ruminal and abomasal administration of feed on the growth and body composition of lambs
Authors: Black JL , Tribe DE
Published: November 2004

The effect of preventing the ruminal fermentation of feed on the perfornlance of growing lambs was investigated by infusing a similar quantity of liquid diet into either the rumen or abomasum of two groups of eight lambs initially weighing 17.5 kg. Each lamb was offered a gross energy intake of 1.11 MJ/day per kg 0 . 73; 62 % being derived from the liquid diet and the remaining 38 % from a pelleted lucerne hay consumed per 0s. Six lambs were slaughtered at the beginning of the experiment to provide an estimate of initial body composition, and the eight lambs from each treatment were slaughtered from 30 to 82 days after commencement of infusions. Separate analyses were made on the blood, commercial carcase, viscera, head plus hooves, skin, and wool. A 3-week digestibility trial was conducted with four lambs from each treatment. Daily gains in body weight, wool growth rate, and the retention of nitrogen and energy were all about twice as great (P < 0.001) in the lambs receiving the abomasal infusions. Abomasal infusion resulted in 24% of dietary nitrogen and 31 % of dietary energy being retained, compared with 12% and 14%, respectively, when the diet entered the rumen. Significantly more of the retained nitrogen and energy was stored in the commercial carcase and less in the wool when the diet was infused into the abomasum. In so far as differences in the mean final weight of lambs given the two treatments made interpretation of body composition results difficult, it appeared that the chemical composition of the whole lamb was not markedly affected by the site of dietary infusion when comparisons were made between animals of the same weight. However, lambs receiving the ruminal infusion contained significantly more protein in the visceral component and had a heavier liver and rumen-reticulum than lambs of similar weight receiving abomasal infusions. The digestibility of all dietary components analysed was significantly less in lambs given the ruminal infusion.
Defoliation, leaf area index, and the water use of four temperate pasture species under irrigated and dryland conditions
Authors: Johns GG , Lazenby A
Published: November 2004

Measurements were made over a 12-month period of the water use and leaf area index (LAI) of both dryland and irrigated monoculture swards of four temperate pasture species under two defoliation regimes. All four species used similar quantities of water on the dryland plots despite large differences in their ability to grow under such conditions. Even though very dry conditions prevailed during part of the study, the dryland swards generally failed to exploit reserves of soil moisture below a depth of c. 120 cm. The water use of the irrigated swards was sensitive to the manipulation of LAI by defoliation, while in contrast, dryland water use was not. On the irrigated swards, at an LAI of 1, a 1% decrease in LAI was associated with a 1% decrease in water use. This sensitivity of water use decreased as LAI increased until, at an LAI of 3 and above, water use appeared to be insensitive to charges in LAI. During the late spring to early autumn period both irrigated and dryland water use were significantly related to LAI. In this period, those irrigated and dryland swards which had common values of LAI generally used similar quantities of water. This finding indicated that stomatal control was ineffective in reducing water use per unit of leaf area. The quantity of dead herbage present in the swards suggests that pronounced leaf senescence (and hence reduction of leaf area) may have been a consequence of ineffective stomatal control of transpiration.
The importance of the salivary glands in the maintenance of phosphorus homeostasis in the sheep
Authors: Clark RC , Budtz-Olsen OE , Cross RB , Finnamore P , Bauert PA
Published: November 2004

Urinary and faecal phosphorus excretion were measured in five sheep for 4 days after acute intravenous infusion of 3.38 g of phosphorus as potassium dihydrogen phosphate. Urinary phosphorus excretion was increased for 12 hr after the infusion, but urinary phosphorus output was small compared with the marked increase in faecal phosphorus output. The increase in faecal phosphorus excretion coincided with and followed the appearance in the faeces of Cr-EDTA, which had been introduced into the rumen as a marker at the time of the phosphate infusion. This suggests that secretion of phosphorus into gut regions below the reticulo-rumen is not quantitatively altered in response to intravenous phosphorus loading, and that phosphorus absorption is also unaffected (at least not on a short-term basis). The additional phosphorus entered the alimentary canal at the level of the reticulo-rumen, and it was deduced that this occurred predominantly via the salivary glands. Persistence of the increase in faecal phosphorus excretion for some time after the Cr-EDTA marker had been cleared emphasizes the importance of the phosphorus recirculation system to ruminants like the sheep.
Effects of Trichostrongylus colubriformis (Nematoda) on the nutrition and metabolism of sheep. I. Feed intake, digestion, and utilization
Authors: Roseby FB
Published: November 2004

The effect of infection with Trichostrongylus colubriformis on feed intake and its digestion and utilization by young Merino sheep was determined in two separate experiments. Intake of a pelleted chaff diet by infected sheep from 11 to 60 days after infection was 20-30% lower than that of the control animals. Digestion and utilization of the same feed were studied in similar sheep fed hourly a ration of 540 g per day. Infected sheep gained body weight more slowly and produced less wool than the controls. Apparent digestibility of organic matter, energy, and nitrogen was not affected. Urinary excretion of urea nitrogen was increased 21 to 30 days after infection, but excretion of creatinine and other nitrogenous compounds was not affected. Nitrogen retention was lower in infected sheep from 20 to 40 days after infection. The urea nitrogen concentration in plasma samples taken at 20 and 30 days after infection was higher in the infected sheep.
Nutritive value of oats and Sudan grass grown at controlled temperatures
Authors: Downes RW , Christian KR , Freer M
Published: November 2004

Fodder oats (Avena sativa L, cv. Cooba) and Sudan grass (Sorghum sudanense cv. Greenleaf) were grown in pots in glasshouses with day/night temperatures of 27/22 and 21/16°C. Plants were harvested at the emergence of each leaf and at various stages after anthesis. Growth rates and changes in dry matter content, nitrogen, cellulose and in vitro digestibility in oats were similar under both temperature regimes, but more primary leaf and less panicle were formed at the high temperatures. Development of Sudan grass was more rapid at the high temperatures, but production of main shoot, panicle and tillers was much less and the nitrogen contents and in vitro digestibilities were consistently lower than at the low temperatures. Sudan grass produced much more dry matter than oats. Differences in composition were in general not large, though stem digestibility remained higher in Sudan grass after anthesis. Tropical species, because of their efficiency of photosynthesis and water use, warrant further study of their nutritive value as forage crops in temperate regions.
The genetic relationship between the digestibility of leaf, stem and whole plant in Setaria
Authors: Hacker JB
Published: November 2004

The genetic interrelationships of in vitro dry matter digestibility of whole plant (DMDWP), leaf (DMDL), stem (DMDS) and terminal two leaf (DMD2L) fractions were investigated in 4-week regrowth of 21 tetraploid clones of Setaria anceps and 14 hexaploid clones of Setaria trinervia. There were significant differences between genotypes of more than eight digestibility units for all fractions, and for all fractions significant positive correlations were obtained between genotype performance at successive harvests. Genotypic and phenotypic correlations between leaf and stem digestibility were mainly positive, but generally low. Genetic correlations for DMDL–DMDWP and DMDS–DMDWP mostly exceeded 0.7 and for DMD2L–DMDL 0.6. Markedly lower values were obtained for the DMD2L–DMDWP comparison. Genotypic correlations for DMDWP-percentage leaf were greater than 0.4 at one harvest. It is concluded that selection for high DMDWP should result in improvement for both leaf and stem digestibility, providing selection was within populations at the same ploidy level. There appears to be little justification for basing selection on the terminal two-leaf fraction, in view of the relatively inconsistent ranking of genotypes in the two successive harvests, and the relatively low genetic correlations between digestibility of this fraction and that of the whole plant.
Effects of high doses of molybdenum and sulphate on the distribution of copper in plasma and in blood of sheep
Authors: Bingley JB
Published: November 2004

Sheep on a daily intake of 120 mg molybdenum and 7.4 g sulphate for 29 months maintained plasma total copper concentrations at twice (P < 0.05) and plasma direct-reacting copper concentrations at 10 times (P < 0.01) the pre-experimental level. Plasma ceruloplasmin levels in these sheep were not significantly increased, but the copper concentration in the red cells was reduced to one-tenth of the normal level (1.0 µg/ml). When the molybdenum dose was progressively diminished, plasma total copper and directreacting copper concentrations remained elevated above the normal until the molybdenum intake was reduced to 12 mg per day. The minimum concentration of copper in the red cells was induced when the molybdenum intake was 96 mg per day. Small amounts of copper detected in the ultrafiltrates of plasma from both treated and untreated sheep were independent of the total plasma concentration. The correlation between non-direct-reacting copper and ceruloplasmin in the plasma, whether determined spectrophotometrically or by its oxidase activity, was high (r = 0.89, P < 0.01). This allowed the use of a regression equation to calculate the non-direct-reacting copper concentration of the plasma. All the copper in the plasma from sheep on a high intake of molybdenum and sulphate could be accounted for in terms of direct-reacting copper, ceruloplasmin copper and ultrafiltrable copper. A significant decrease (P < 0.01) in the copper concentration of the wool was caused by treatment of the sheep with molybdenum and sulphate. At the end of the period the haemoglobin concentration in the blood of the sheep on the continuous high dose of molybdenum and sulphate had fallen 30%, but the weight of the sheep was maintained, and apart from the condition of the wool, no clinical signs of copper deficiency were observed.
Factors involved in the amelioration of retarded symbiosis in Tinaroo glycine
Authors: Diatloff A
Published: November 2004

Root nodules formed on Tinaroo glycine (Glycine wightii) were slow to pigment and begin fixing nitrogen. Various carbon and nitrogen compounds enhanced nodule pigmentation, the greening of the plants, and the rate of nitrogen fixation at 42 days. Of these inositol, glucose, ammonium nitrate (as both foliar and root applications) and coconut milk were most effective. Riboflavin, sodium glutamate and nodule infusion had little effect. There were no structural differences between nodules enhanced respectively by glucose and ammonium nitrate. Nodules on control plants showed slow development of the bacteroids and envelope membranes, with copious starch accumulation in uninvaded host cells. It was concluded that the retarded symbiosis in formed nodules was due initially to tardy nodule formation depleting the nitrogen reserves in the seeds before nitrogen fixation began. Because of the interaction of photosynthesis and nitrogen fixation, self-regeneration of nitrogen fixation in chlorotic plants was slow without an external stimulus. It is suggested that by selecting lines of the legume with larger seeds or by incorporating nitrogen in seed pellets the problem might be overcome.
Effects of formaldehyde treatment of casein and peanut meal supplements on amino acids in digesta and plasma of lambs and sheep
Authors: Faichney GJ
Published: November 2004

The passage of amino acids into the duodenum and the levels of amino acids in jugular plasma were studied (a) in lambs given a supplement of casein with or without formaldehyde treatment, and (b) in sheep given concentrate diets containing treated or untreated peanut meal at both a low and a high level of dietary protein. When casein in the diet was treated with formaldehyde, losses of individual amino acids due to degradation in the rumen were substantially reduced or prevented so that the amounts reaching the small intestine were substantially increased. This increase in supply of amino acids, which was associated with an increase in the rate of liveweight gain, caused an increase in the plasma levels of most amino acids. However, lysine levels tended to fall, and this resulted in marked reductions in the molar proportion of lysine. When sheep were given formaldehyde-treated peanut meal, the amounts of the individual amino acids reaching the small intestine were greater than when untreated peanut meal was given. When the meal in the higher protein diet was treated, the losses due to degradation were again largely prevented. As amino acid supply to the small intestine increased, the plasma levels of most of the individual amino acids decreased to a minimum and then increased when supply exceeded demand. The molar proportion of lysine decreased when peanut meal in the higher protein diet was treated. An increase in plasma s-N-methyllysine level was characteristic of formaldehyde treatment of dietary protein. Changes in arginine levels tended to be inversely related to changes in total amino acid levels.
Corrigendum - The effect of formaldehyde treatment of a casein supplement on urea excretion and on digesta composition in sheep
Authors: Faichney GJ
Published: November 2004

The urinary excretion of urea, the fate of an intravenous dose of urea, overall nitrogen metabolism and the composition of rurnen and abomasal samples were studied in crossbred sheep given a basal roughage diet to which supplements of starch, casein or formaldehyde-treated casein were added. Urea excretion was closely related to plasma urea level (r = 0.935) and to the filtered load of urea (r = 0.957). The amount of urea reabsorbed by the kidney increased as'the amount filtered increased; the relationship was improved when values obtained at urine flow rates less than 1 rnl/rnin were omitted. When sheep were given the starch and treated casein diets, the rate at which they cleared a small dose of urea from their plasma was greater than the renal clearance rate; only 75% of a large dose was recovered in the urine. The capacity to dispose of exogenous urea by extra-renal pathways was apparent only when rumen ammonia nitrogen levels were less than about 200 mg/l. Formaldehyde treatment reduced nitrogen digestibility but reduced urine nitrogen excretion to a greater extent so that nitrogen retention increased. Treatment was associated with reduced plasma urea levels, reduced rumen and abomasal ammonia levels, reduced total VFA levels, increased proportions of acetic acid and decreased proportions of isobutyric, isovaleric and n-valeric acids, and more protein in abomasal contents.
Prediction of body composition in live sheep
Authors: Donnelly JR , Freer M
Published: November 2004

New and published data on the chemical composition of 149 Merino and Merino crossbred sheep covering a wide range of age were used to derive regressions of body water, protein, ash and fat on parameters measured in the live animal. Allometric models were tested with fasted liveweight (W), tritiated water space (T) and maturity (M) as predictors, maturity being the age of the sheep as a proportion of the age at which mature size is reached. For all body components the inclusion of maturity in the following equations substantially reduced the residual standard deviation (RSD), compared with allometric or multiple linear regression models that included only W and T as predictors. In addition it largely eliminated bias from the predicted values for the six separate groups of sheep from which the data were obtained. Total body water (kg) = 1.179T0.926M0.031 (RSD = ?0.354)
Protein in empty body (kg) = 0.408 W0.708M0.092 (RSD = ? 0.264) Ash in empty body (kg) = 0.305 W0.460M0.290 (RSD = ? 0.100)
Fat in empty body (kg) = 0.117(W – T)1.592M-0.225 (RSD = ? 0.444)
It is suggested that in future work a measure of skeletal size in the live animal may increase the precision of these equations.
Studies of grain production in Sorghum bicolor (L. Moench). IV.* Some effects of increasing and decreasing photosynthesis at different stages of the plant's development on the storage capacity of the inflorescence
Authors: Fischer KS , Wilson GL
Published: November 2004

Sorghum plants (cv. RS610) grown in field stands at two population densities were manipulated to increase the supply of assimilates (by removing neighbouring plants) at one of three developmental stages—10-15 days after floral initiation, 1 week prior to three-quarters anthesis, and 1 week after three-quarters anthesis. Post-initiation exposure increased the number of grains per inflorescence 1.8-fold and 3.5-fold in medium and high density populations respectively, but had relatively less effect on grain size. Higher grain number resulted largely from more grains per secondary branch in the lower part of the inflorescence. Neither of the post-heading exposure treatments influenced grain number, but the higher supply of assimilates resulted in larger grains at both densities. Differences at one density only between yield characteristics of plants exposed at the two times provide evidence of inter-plant competition for assimilates to the extent that the potential size of the grain may be affected. Shading (10% light transmission) of plants grown in a glasshouse, whether for 1 week at anthesis or during grain filling, reduced grain yield at maturity by the same amount as the immediate reduction at the end of the shading period. The experiment was unable to demonstrate changes in the potential size of grains resulting from the loss of assimilates at anthesis. There was substantial compensation for the loss by translocation from other plant parts.

*Part III, Aust. J. Agric. Res., 26: 11 (1975).
Superphosphate utilization in clover ley farming. II.* Residual effects of pasture topdressing in the cropping phase
Authors: Kohn GD
Published: November 2004

A grazing experiment was carried out at the Agricultural Research Institute, Wagga Wagga, over the period 1962-1966. The treatments involved three stocking rates (5, 10 and 15 sheep per ha) and four superphosphate topdressing rates (0, 125, 250 and 375 kg ha-1) with three replications. After the grazing phase three successive crops were grown. Superphosphate was applied with the crops at 0, 63, 125 and 250 kg ha-1. Current and residual effects of this superphosphate were measured. Nitrogen (as urea at 78 kg ha-l) was topdressed on half of each plot. The low stocking rate plots were further tested for response to sulphur. Superphosphate applied to one crop had no residual effect on subsequent crops, regardless of the previous pasture treatment. On the average the yield of the first crop sown without superphosphate increased about 1/3 kg ha-1 for each kilogram of superphosphate per hectare applied annually in the pasture phase, that of the second crop 1 kg and the third crop I-1/3 kg. First crops did not respond to superphosphate applied with the crop, but second crops on plots that were not topdressed in the pasture phase and all third crops did respond to current superphosphate. Yields of third crops receiving superphosphate at 250 kg ha-1 on land that was not topdressed in the pasture phase exceeded those of similar crops on land that had been topdressed in the pasture phase (five out of six comparisons were significant at P = 0.01). A similar effect was found in the second crop in one replicate. The effect of nitrogen varied with the climate. In the drought year of 1967 there was one negative response to nitrogen. In 1968 yields were high and nitrogen decreased yield by increasing lodging. In the following 3 years nitrogen increased yield and the increase was generally greater as the rate of pasture topdressing increased. The stocking rate of the pasture did not affect the yield of the following wheat crops. There was no response to sulphur by the crops. It is suggested that superphosphate can be more efficiently used by omitting pasture topdressing and applying 125 kg ha-I or more with crops. Farmers in the clover ley farming areas could considerably reduce their annual superphosphate requirements.

*Part I, Aust. J. Agric. Res., 25: 525 (1974).
Use of alkaline earth metals to reduce the incidence of storage disorders of apples
Authors: Wills RBH , Scott KJ , Carroll ET
Published: November 2004

Application of barium and strontium salts to apples was found to reduce the incidence of both internal breakdown and bitter pit. However, they did not appear to be more effective than calcium in reducing these disorders.
Studies on the distribution of the body fat in sheep during continuous growth, and following nutritional restriction and rehabilitation
Authors: Little DA , Sandland RL
Published: November 2004

Merino wether sheep were completely dissected at c. 3,6 and 12 months of age following steady growth. Further 12-month-old animals were subjected to nutritional restriction producing a liveweight loss of some 25%; dissections were carried out at this point, and following a 30% rehabilitative gain in liveweight. Two animals were involved at each dissection point. Total body fat was separated into the dissectible visceral, intermuscular and subcutaneous The restricted animals contained the same amount of fat per unit of wool-free empty body weight as did those grown continuously, but the rehabilitated animals did not. Rehabilitation was associated with the accumulation of less fat and more protein and water than occurred during steady growth. Nutritional restriction caused a relatively greater loss of fat from the subcutaneous depot than occurred through the body fat as a whole, and some further deposition of fat occurred in the skeleton. This resulted in the restricted animals having, at comparable amounts of body fat, a significantly lower proportion in the subcutaneous depot and a higher proportion in the skeleton than had continuously grown animals. Rehabilitation to the degree employed in this work did not restore the normal contributions of those fat depots to total fat. Total intramuscular fat could not be predicted from the fat content of samples from five superficial muscles, nor was the relationship of intramuscular fat to total body fat sufficiently close for predictive purposes.
Characteristics of the canopy, root system and grain yield of a crop of Lupinus angustifolius cv. Unicrop
Authors: Greenwood EAN , Farrington P , Beresford JD
Published: November 2004

The time course of development of a lupin crop was studied at Bakers Hill, Western Australia. The aim was to gain insight into the crop factors influencing yield. Weekly measurements were made of numbers and weights of plant parts, and profiles of roots, leaf area and light interception. A profile of carbon dioxide in the crop atmosphere was taken at the time of maximum leaf area, and the net carbon dioxide exchange (NCE) of pods was estimated for three successive weeks. The crop took 10 weeks to attain a leaf area index (LAI) of 1 and a further 9 weeks to reach a maximum LAI of 3.75, at which time only 33% of daylight reached the pods on the main axis. Once the maximum LAI was attained at week 19, leaf fall accelerated and rapid grain filling commenced almost simultaneously on all of the three orders of axes which had formed pods. Measurements of NCE between pods on the main axis and the air suggest that the assimilation of external carbon dioxide by the pods contributed little to grain filling. Grain dry weight was 2100 kg ha-1 of which 30%, 60% and 10% came from the main axis, first and second order apical axes respectively. Only 23% of the flowers set pods and this constitutes an important physiological limitation to grain yield.
Humidity, free water and light in relation to development of Kabatiella caulivora (Kirchn.) Karak in Trifolium subterraneum L. cv.Yarloo
Authors: Helms K
Published: November 2004

The effects of moisture conditions on disease development and plant growth were examined in subterranean clover plants which were inoculated with K. caulivora 4 weeks after sowing and were maintained after inoculation at 20°C and with a light intensity of 2000 f.c. In plants which received 100% relative humidity (RH) with free water on leaves, for at least 4 days after inoculation, 15–20% of leaves developed lesions within 11 days. In plants which received continuously 90% RH with free water on leaves, or 100% RH without free water on leaves, less than 1.5% of leaves developed lesions within 11 days. There was no evidence of spread of infection in plants maintained for 11 or 25 days after inoculation. The effects of light intensities of 2000, 500 and 125 f.c. on disease development and plant growth were examined in plants which received 100% RH with free water on leaves and were grown for 25 days after inoculation, either in simulated swards or in standard pots. In most treatments a reduction in light intensity from 2000 to 500 f.c. reduced the growth of plants but had no effect on the percentage of diseased leaves, whereas a reduction in light intensity from 500 to 125 f.c. reduced growth and increased the percentage of diseased leaves of plants grown in swards from 30 to 70% and in standard pots from 10 to 35%. There were mortalities among both inoculated and control plants grown under 125 f.c. : in swards, 80–90% of inoculated plants and 30–40% of control plants died, whereas in standard pots 20–30% of inoculated plants and only occasional control plants died. The data show that environmental conditions favourable for the development of the disease were unfavourable for growth of control plants.
Methionine supplementation of milk proteins for preruminant lambs. I. Effect of protein concentration and source of carbohydrate on nitrogen balance
Authors: Walker DM , Kirk RD
Published: November 2004

Forty-seven crossbred lambs, aged 2–5 days at the start of the experiment, were used in three experiments. In experiment 1 a supplement of DL-methionine significantly increased the nitrogen balances of lambs given low or medium protein milk replacers based on cows' milk proteins. In experiment 2 the optimum level of supplementation of a low protein diet with DL-methionine was determined. Although the nitrogen balances were significantly increased by the supplement, the actual nitrogen balances at equivalent intakes of gross energy and nitrogen were less than those in experiment 1. The low protein diets in the two experiments differed only in the source of carbohydrate: lactose in cxpcrimcnt 1; lactose + glucose in experiment 2. In the final experiment 24 lambs in a 2 x 2 factorial design were fed on low protein diets containing casein as the source of protein, and lactose or glucose as the sole source of carbohydrate, with or without a supplement of DL-methionine. There was no significant effect of the source of carbohydrate on nitrogen balance.
Ecological studies on reproduction and establishment of the woody weed, groundsel bush (Baccharis halimifolia L.: Asteraceae)
Authors: Westman WE , Panetta FD , Stanely TD
Published: November 2004

Groundsel bush (Baccharis halimifolia) is spreading southward along the coastal range of eastern Australia where the annual rainfall exceeds 90 cm. This advance conforms with its cool temperature optimum for germination (15-20�C) and its superior germination when given a cold pretreatment (5�C for 1 week). The species has a facultative light requirement for germination, which suggests that the maintenance of a very dense vegetative cover in the herb layer could discourage establishment of the weed. Once established, however, B. halimifolia can produce viable seed in very dense shade (3 % of open light conditions), even though total seed production per plant is reduced. Prolific seeding occurs with high light intensity. Thus a tall plant (2 m) may release c. 1.5 million seeds. Seedlings possess an unusual ability to maintain growth under low nitrogen conditions during their first 13 weeks, and to survive even when the supply of all nutrients is poor. Seedlings showed no growth response when the strength of a standard nutrient solution was doubled. The fact that growth is not inhibited under enriched nutrient conditions, however, may account for the superior competitive performance of B, halimifolia on fertilized sites containing native coastal species adapted to low soil fertility. Implications with respect to integrated control of the weed are briefly discussed.
Response to selection in Australian Merino sheep. VII. Phenotypic and genetic parameters for some wool follicle characteristics and their correlation with wool and body traits
Authors: Jackson N , Nay T , Turner HN , Newton Turner H
Published: November 2004

Four numerical characteristics-follicle depth, follicle curvature, number of follicles per unit area of skin, and ratio of number of secondary to number of primary follicles-describing the size, shape, and arrangement of wool follicles have been measured in Peppin Merino sheep at 4-5 months (weaning), 15-16 months (two-tooth shearing) and at later ages ranging from 2 1/2 to 7 1/2 years. Estimates of their repeatability, heritability and phenotypic, genetic, and environmental correlations with 10 wool and body characteristics are reported. All four follicle characteristics were found to be highly inherited and sufficiently correlated with wool characteristics to be of interest to both the wool biologist and the sheep breeder. Fixed environmental effects influenced the expression of some follicle characteristics, while others, notably follicle curvature at any age, were unaffected, and therefore potentially more useful as practical selection aids. Groups of sheep selected for clean wool weight with control of (i) fibre diameter and wrinkle score, and (li) crimp frequency and wrinkle score, exhibited changes in the four follicle characteristics, which agreed with what the genetic correlation estimates would predict. The role of follicle characteristics in the biology of genetic control of wool growth is portrayed by fitting causal models invoking follicle characteristics as intermediates between the gene and the wool character. The analysis separates three independent genetic control systems, the identity of which corresponds closely to factors postulated in previous theoretical studies.
The relationship between the phosphorus status of subterranean clover plants and the dry weight responses of detached leaves in solutions with and without phosphate
Authors: Bouma D , Dowling EJ
Published: November 2004

In four experiments subterranean clover plants (Trifolium subterraneum L., cv. Mt. Barker) were grown at different levels of phosphorus applied to solution cultures, to Perlite and to pots containing phosphorus-deficient soil. Leaves detached from deficient plants, placed in 3mM fructose 1,6-diphosphate or in 6mM NaH2PO4.2H2O for periods of 8–12 hr and then in distilled water under fluorescent lights (31,000–33,000 lx) for total light periods of 75–115 hr (18 hr light per 24 hr), showed greater increases in dry weight than corresponding leaves placed in distilled water without an initial phosphate treatment. By contrast, there were no differences in dry weight increases between similarly treated leaves from non-deficient plants; thus a clear distinction could be made between deficient and non-deficient plants. Dry weight increases of deficient leaves during the light period were markedly dependent on the length of the preceding period in phosphate solutions. Maximum increases occurred after periods of 8–12 hr, depending on the degree of phosphorus stress of the leaves. For non-deficient leaves initial uptake periods of up to 12 hr gave dry weight increases under the lights close to or the same as those of leaves in distilled water only, while periods of 24 and 48 hr resulted in greatly reduced dry weight increases. The possible application of the results as the basis for a simple diagnostic technique is discussed.