bluuebunny/crossref_metadata_2025 huggingface dataset:
Oestrous, ovarian and adrenal response of the ewe to fasting and cold stress
Authors: MacKenzie AJ , Thwaites CJ , Edey TN
Published: November 2004

The effect of acute stress on oestrus and ovulation rate in 40 mature Border Leicester x Merino ewes was examined in a factorial experiment utilizing the following fasting and shearing treatments: group HW, feeding ad lib., unshorn; group HS, feeding ad lib., shorn; group LW, fasted, unshorn; and group LS, fasted, shorn. The experiment was conducted in June–July and treatments began 7 days before the expected day of onset of the second oestrus following withdrawal of a progestagen pessary. Ovulation rates were determined by laparotomy or slaughter on days 2–4 following the onset of oestrus. Climatic data were collected twice daily and the severity of the stress experienced by the ewes was assessed by macroscopic and histochemical examination of the adrenal glands in a subsample of each treatment group. Severe conditions of cold, wind and rain occurred throughout the experimental period, and lipid accumulation in the adrenal cortex indicated that a physiological stress reaction had been invoked, particularly in the fasted groups (LW, LS). Fasting or shearing had no apparent effect on ovulation rate but a significant suppression of behavioural oestrus was observed in both treatments. While all ewes exhibited oestrus in the control group, shearing (HS) and fasting (LW) treatments reduced the incidence of oestrus to six ewes out of 10 and seven out of 10 respectively. In the fasted and shorn group, only three out of 10 ewes exhibited oestrus.
Influence of saline drinking water on the flow and mineral composition of saliva and rumen fluid of sheep
Authors: Tomas FM , Potter BJ
Published: November 2004

The influence of sodium chloride ingestion via the drinking water upon the flux of fluid and minerals to and from the rumen of sheep has been examined. Four Merino wethers were each prepared with ruminal and bilateral parotid duct fistulas to allow continuous sampling and measurement of flow rates and were offered rainwater which was zero, 136 or 221mM with respect to sodium chloride as the only source of drinking fluid. Parotid salivary flow rate decreased by up to 43% when the saline concentration of the drinking water was increased. There was an inverse relationship between saliva flow rate and the fluid intake, but much of the effect appeared to be due to ingestion of sodium chloride per se. Salt water ingestion caused an increase in the salivary concentration of sodium and phosphate; a decrease in that of potassium; and no change in that of chloride or osmolality. The rate of secretion of sodium varied directly with saliva flow rate. The outflow of water from the rumen to the omasum, or its net absorption across the rumen wall, were not influenced by treatment. In centrifuged rumen fluid samples saline ingestion caused increased levels of sodium, chloride and osmolality; decreased levels of potassium; and no change in calcium, magnesium or phosphate. Outflows of sodium and chloride to the omasum were increased. The apparent absorption of sodium and chloride from the rumen increased proportionately to the inflows of these ions via the saliva and drinking fluid. The additional sodium and chloride ions arising from the ingested saline were absorbed in approximately equal amounts. Saline drinking by sheep leads to a reduction in the rate of secretion of parotid saliva and its accompanying ions, which partially compensates for the added amount of fluid and electrolyte which enter the rumen in the drinking water.
Genetic influences on the split seed disorder in Lupinus angustifolius L.
Authors: Walton GH , Francis CM
Published: November 2004

During an investigation of the disorder known as split seed in narrow-leafed lupins (L. angustifolius) studies were made on an F2 population from a cross between the 'bitter' cultivar New Zealand Blue and the 'sweet' cultivar Uniwhite. In a situation where the split seed problem occurred, the presence of the gene for low alkaloid (iucundus) in the homozygous state lowered the proportion of normal seeds from 78.5 to 10.9%, and the non-shedding phenotypes (tardus), in the absence of iucundus, showed reduction of normal seed from 81.8% to 62.4%.
Additional experiments with a wider range of genotypes verified the invoivement of the iucundus gene and showed that the Ku gene for earlier flowering could provide a degree of escape from the disorder. The split seed relationship with iucundus and tardus showed differences in expression at one site, which indicated a difference in their mechanism of action at least in the production of severely deformed or shrivelled seed.
Effect of high intakes of sodium chloride on the utilization of a protein concentrate by sheep. II.* Digestion and absorption of organic matter and electrolytes
Authors: Hemsley JA , Hogan JP , Weston RH
Published: November 2004

The effects of the ingestion of large amounts of sodium chloride (c. 150 g/day) on digestion and absorption were examined in sheep offered a diet consisting of 89% linseed meal. Although water intake was increased by only 2 litres per day, the rate of flow of fluid from the rumen and digesta from the abomasum increased by 5–6 kg/day and the mean residence time of a soluble marker was reduced from 20 hr to 12 hr. Digestion of organic matter in the stomach was reduced by c. 24% but the reduction in protein digestion was only 10%. The concentrations of protozoa and selenomonads in the rumen were reduced by the salt treatment. Approximately 50% of the ingested sodium and chloride was absorbed from the stomach in sheep on the high salt diet, although levels of sodium and chloride in the rumen did not exceed those in the plasma. Osmotic pressures in the stomach fluids and in the plasma were elevated by the salt treatment, although levels of sodium in plasma were unaffected. Plasma chloride and potassium levels were both increased by the salt treatment.

*Part I, Aust. J. Agric. Res., 26: 709 (1975)
Whole wheat grain feeding of lambs. IV.* Effects of an antibiotic, lactic acid, grain moistening and restricted intake on wheat sickness of young sheep
Authors: Bigham ML , McManus WR
Published: November 2004

Two studies are reported in which young lambs were changed rapidly from roughage diets to whole wheat diets and subjected to various treatments aimed at facilitating adaptation to the wheat diet. In pen feeding studies, groups of three sheep with rumen cannulae were used to investigate the effects of the various treatments on wheat sickness. The treatments included intraruminal administration of sulphadimethoxine before and during wheat feeding; moistening; and restriction of grain intake. The studies indicated that except perhaps for restriction of intake, none of the methods used was successful in reducing the build-up of lactic acid and decline in rumen pH and therefore wheat sickness. Sulphadimethoxine did not have a major effect on volatile fatty acid or lactic acid production when wheat grain was consumed. In an antibiotic dose response trial, 59 lambs were changed from roughage to wheat grain diets, restricted amounts of wheat grain with sulphadimethoxine being offered at four levels (0, 45.4, 136.3 and 272.7 mg/kg liveweight). The drug proved to be toxic and the lamb mortality (5, 23, 39 and 62%) rose as the dose increased. Results are discussed in relation to metabolic and practical aspects of wheat grain feeding of lambs and the need for further work to seek practical means for regulating intake under group feeding conditions.

*Part III, Aust. J. Agric. Res., 24: 425 (1973).
Surveys of Fusaria associated with crown rot of wheat in eastern Australia
Authors: Burgess LW , Wearing AH , Toussoun TA
Published: November 2004

Fusavium voseum 'Graminearum' was found to be the predominant fusarium associated with crown rot of wheat in the eastern wheat belt of Australia. This conclusion was based on quantitative surveys involving isolations from stem bases of crown rot-affected plants at growth stages 10.5-11 which were collected at random in the 1972, 1973 and 1974 growing seasons. The majority of the isolates of F. roseum 'Graminearum' did not form perithecia in culture or on sterile wheat straw and are referred to as group 1 isolates to distinguish them from group 2 isolates which normally form perithecia in culture. The two groups can also be distinguished on the basis of cultural characteristics. Several group 2 isolates were obtained from wheat stem bases. The results indicate that the incidence and severity of crown rot caused by F. roseum 'Graminearum' was greater in areas where plants were affected by low soil moisture. The disease was found to occur in all areas of the eastern wheat belt which were surveyed.
Surveys of Fusaria and other fungi associated with stalk rot of maize in Eastern Australia
Authors: Francis RG , Burgess LW
Published: November 2004

Fusarium roseum 'Graminearum' was the predominant fungus associated with stalk rot of maize in eastern Australia in the 1972, 1973 and 1974 growing seasons. All isolates of this pathogen were of the group 2 type. Other fungi isolated in order of frequency were Diplodia maydis, F. moniliforme 'Subglutinans', Bipolaris sorokiniana, Nigrospora oryzae, F. roseurn 'Semitectum', F. moniliforme, F. roseurn 'Equiscti', F. roseum 'Concolor', Macrophominaphaseolina, Rhizoctonia sp., F. roseum 'Acuminatum', F. oxysporum, F. solani, F. tricincturn and F. roseum 'Heterosporum'. The relative isolation frequencies of the fungi varied according to the seasonal conditions. Stalk rots were not of major importance in 1973, a relatively dry growing season. However, in 1974, a wet growing season, stalk rot diseases were common in all areas.
Metabolic studies on daily and weekly feeding of ruminants given all-wheat diets. 2. Concentrations of metabolites in blood and ruminal fluid
Authors: Watson MJ
Published: November 2004

The respective effects of giving sheep 300 g whole wheat once each day or 2100 g once each week on the products of digestion in the rumen and the concentrations of several metabolites in the blood have been studied. Some studies were also made on cattle offered either daily or weekly rations of whole wheat. Related to the differing patterns of feed consumption on the two regimens, the fluctuations in ruminal fluid parameters were much greater for sheep and cattle fed weekly than on the daily feeding regimens. In sheep the mean total volatile fatty acid concentration and pH in ruminal fluid were similar on the two regimens, while when cattle were fed weekly, the volatile fatty acid concentration was higher (not significantly) and the pH lower. Weekly-fed sheep had lower rumen ammonia and branched-chain volatile fatty acid concentrations, whereas in cattle there was no difference between regimens. The rumen concentration of valeric acid was higher in both sheep and cattle fed weekly. In daily-fed sheep there was no diurnal variation in the concentrations of blood metabolites with the exception of free fatty acids. In contrast in weekly-fed sheep, the large changes in concentration of D(-)-glucose, L(+)-lactate, 3-hydroxybutyrate, urea and free fatty acids indicated phases of protein synthesis and lipogenesis following feeding, and protein and lipid mobilization at the end of the feeding cycle. It was concluded that in weekly-fed sheep there was a shift in the site of digestion from the rumen to the small intestine, but in cattle there was no evidence that the sites of digestion differed substantially between the two regimens.
Comparative aspects of digestion of four roughages by sheep
Authors: Egan AR , Walker DJ , Nader CJ , Storer G
Published: November 2004

Movement of digesta through the reticulorumen and through the intestines has been studied for four roughage diets (wheaten straw, ws; wheaten hay, WH; lucerne hay, LH; dried subterranean clover, sc; all in chopped form) given to sheep fitted with re-entrant duodenal cannulas. The extent and tbe sites of digestion of plant organic matter and its constituent soluble sugars, polysaccharides, pectin, and protein are described for the four roughages. Sugars, water-soluble polysaccharides and pectin were completely digested on all diets, almost entirely in the stomachs. Together these fractions contributed 16, 21, 25 and 27% of the apparently digested organic matter respectively for ws, WH, LH and sc diets. The digestibility of hemicellulose ranged from 49.5% (WH) to 80.9% (sc); of the hemicellulose digestcd, from 70% (WH) to 81 % (sc) was apparently fermented in the reticulorumen. The digestibility of cellulose ranged from 58 % (WH) to 88 % (sc), and of the cellulose digested, 83 % (WH) to 89 % (sc) was apparently fermented in the reticulorumen. Together, apparently fermented cellulose and hemicellulose contributed from 25 %: (sc, LH) to 55 % (ws) of apparently digested organic matter. Despite evidence of nitrogen loss across the reticulorumen on thee two high nitrogen diets (LH, - 10 %; sc, - 22 %) and net gains in nitrogen on the two lower nitrogen diets (ws, + 50 %; WH, +20%), the yield of all amino acids at the duodenum per 100 g digestible organic matter intake was about 50 % higher for LH and sc (which were similar) than for ws and WH (which were similar). The relative proportions of essential amino acids did not change significantly. Nutritional implications of these changes in the site of digestion and of the proportions of nutrients released to the animal are discussed.
The effect of lupinosis on the nutritional value of lupins to sheep
Authors: Hill JL , Arnold GW
Published: November 2004

Lupin and non-lupin hays were fed to sheep in metabolism cages to compare their nutritive values and to assess the effects of lupinosis on food intake, digestion and metabolism. Abnormal cyclic fluctuations in voluntary food intake, sometimes ending in inappetence, occurred in all three experiments. These fluctuations in food intake were shown to be associated with lupinosis and caused considerable variability in all experimental measurements. In spite of this variability, the intake of digestible organic matter of four of the seven lupin hays was equivalent to that of the non-lupin hays. In the other three it was significantly less. The in vivo lupin hay digestibilities ranged from 52.3 to 65.0%. Rumen protozoa counts were made in one experiment and were lower in sheep receiving lupin hay containing lupinosis toxin than in those receiving a non-lupin hay, but all values were still within the biologically 'normal' range. Irrespective of the presence of lupinosis toxin, no significant differences could be established in parameters of either energy or nitrogen metabolism of sheep fed on the various hays. We conclude that hays from lupins cut at the late flowering stage have a similar nutritive value to hays made from temperate pasture species, even when there were intakes of low levels of lupinosis toxin.
Vernalization as a factor influencing the rate of development in subterranean clover (Trifolium subterraneum L.)
Authors: Collins WJ , Smith DF
Published: November 2004

An investigation of the influence of vernalization on the rate of development in three cultivars of subterranean clover was conducted under controlled environmental conditions. Effects were evaluated in terms of the time from imbibition to flower initiation or flowering, i.e. including the time during which vernalization was imposed. In these terms, vernalization actually delayed flowering in the Yarloop and Mt. Barker cultivars, hastening it only in Tallarook. Some practical considerations are discussed. The effects of periods of higher temperatures after vernalization on the rate of development were also studied. No evidence was found for the occurrence of devernalization. If devernalization docs occur in subterranean clover, it is unlikely to be of practical consequence in normal field situations.
Effects of depth of fertilizer placement on wheat grown under three water regimes
Authors: Alston AM
Published: November 2004

Wheat was grown in reconstructed profiles of a sandy red-brown earth in pots 120 cm deep. Ammonium sulphate (40 mg nitrogen per pot) and/or monocalcium phosphate (75 mg phosphorus per pot) were placed either in the topsoil at 5 cm depth or in the subsoil at 25 cm. When the wheat reached ear emergence, water treatments were introduced to provide (a) dry topsoil and water shortage; (b) dry topsoil but ample water supply in the subsoil; or (c) an ample water supply with both topsoil and subsoil wet. The yield and concentrations of nitrogen and phosphorus in the wheat and the distribution of roots in the soil were measured at maturity. Water use by the plants was calculated. Drying of the topsoil decreased grain yield and uptake of nitrogen and phosphorus by the wheat, but the effects were small compared with those of water shortage per se. Placement of nitrogen and phosphorus at 25 cm produced higher grain yields than placement at 5 cm. There was no interaction between placement depth and the water treatments: this indicated that reduced availability of nutrients because of dry topsoil after ear emergence was not a major factor limiting yield. The fertilizer treatments affected the distribution of roots more than total root length. Root growth increased at the site of placement where nitrogen and phosphorus, and to a lesser extent nitrogen alone, were applied in the subsoil; there was little effect in other parts of the profile. Efficiency of water use was increased by the application of nitrogen.
Importance of soil moisture and temperature on the growth of improved pasture on the Northern Tablelands of New South Wales
Authors: Smith RCG , Stephens MJ
Published: November 2004

A simple model for predicting pasture growth from climatic data was developed and tested against experimental data. The model was used to analyse climatic data from a 24-yr period (1950–1973) to elucidate the relative importance of soil moisture and temperature on the growth of improved pastures on the Northern Tablelands of New South Wales, and to predict the year-to-year variations in total pasture growth.Predicted yearly dry matter production varied between extremes of 5000 kg ha-1 yr-1 in 1965 and 14,000 kg ha-1 yr-1 in 1971. Soil moisture was the major factor limiting pasture growth from the beginning of October until the end of May, and temperature was the major limiting factor from the end of May to early October. During May and October there was a period when both factors had a similar probability of being the most limiting factor. Variations in soil moisture caused greater within-year variability in pasture growth than temperature except in April and September when variability caused by temperature equalled that caused by soil moisture. The significance of these effects is discussed.
Effect of starch on the utilization by sheep of a straw diet supplemented with urea and minerals
Authors: Mulholland JG , Coombe JB , McManus WR
Published: November 2004

Individually penned Border Leicester x Merino wethers, aged 11 months, were fed ad lib. for 16 weeks on a basal ration of ground, pelleted oat straw, urea and minerals, supplemented with 0, 5, 10, 15, 20, 30 or 40% starch. The diets contained equal percentages of nitrogen and minerals. Dry matter intake reached a maximum of 2000 g/day with 30% starch; above this starch level, digestive disturbances were observed. Organic matter digestibility was increased by the addition of starch, but cellulose digestibility was depressed by as much as 18 units with the addition of 30% starch. Up to 10% the starch level had little effect on cellulose digestibility. Liveweight change was significantly correlated with digestible organic matter intake, mean daily weight gains varying from 22 g with no starch to 104 g with 30% starch. However, a large percentage of the liveweight gain was as total body water, and body energy storage increased appreciably only when the diet contained at least 20% starch. The inclusion of 5% starch slightly depressed both intake and liveweight gain. Daily clean wool production was significantly increased at starch levels higher than 20% and ranged from 5.3 to 7.5 g/day with 0 and 40% starch respectively. Increasing levels of starch had little effect on apparent nitrogen digestibility, but resulted in a substantial increase in nitrogen retention through a reduction in urinary nitrogen excretion. Serum urea levels fell from a mean of 42 mg/100 ml during the first week to 31 mg/100 ml during subsequent periods, with no significant differences between diets. With the general exception of potassium, mineral balances were positive or close to zero throughout the experiment.
Effect of coumestans on reproduction in the ewe
Authors: Kelly RW , Adams NR , Lindsay DR
Published: November 2004

In an experiment to study the effect of the ingestion of coumestans on reproductive variables in the ewe, pelleted feed containing c. 1000 ppm coumestans was given to nulliparous Merino ewes for varying periods (6.5 and 19.5 days) during their oestrous cycle. In a second experiment a similar diet was given to mature Merino ewes over days 12–18 of their oestrous cycle. Only 17% (12/69) of the total number of ewes on this diet came into oestrus, compared with 92% (35/38) of ewes given a phyto-oestrogen-free diet. Of the ewes given coumestan-rich feed that were detected in oestrus, 58% (7/12) did not have a recently formed corpus luteum at laparotomy. Injection of 25 µg oestradiol benzoate on day 16 of the oestrous cycle induced oestrus but not ovulation in ewes on the coumestan-rich diet. Follicular abnormalities indicative of strong oestrogenic stimulation were detected in the ovaries of ewes ingesting coumestans. It was suggested that coumestans inhibit oestrus through inhibiting the production of endogenous oestrogen.
Sites of digestion in the calf. I. The digestion of diets containing barley and wheat chaff supplemented with soya bean meal or urea
Authors: Leibholz J
Published: November 2004

Four Friesian bull calves were fitted with re-entrant duodenal cannulae within 1 week of birth. From 13 weeks of age the calves were fed on one of three diets all containing 17% crude protein. Diet A contained barley, 15% wheat chaff and soya bean meal, diet B barley, 15% wheat chaff and urea, and diet C barley, 45% wheat chaff and soya bean meal. The diets were given for 2 weeks, and on the last day of each feeding period total collections were made of the digesta leaving the abomasum over a 12 hr period. The diets were then changed so that each calf was offered each diet twice. The total apparent digestion of the organic matter in the diet containing 45% wheat straw was less than that of those containing 15% wheat straw. This was due to less digestion in both the stomach and hindgut. The flow of nitrogen from the abomasum, expressed as a percentage of the nitrogen intake, was less when the calves were fed on the diet containing urea (B) than when they were fed on those containing soya bean meal (A and C). Also, a larger proportion of the nitrogen was of microbial origin when they were on diet B. The proportion of essential amino acids in the total amino acids flowing from the abomasum was greater than that in the total amino acids present in all diets. Also, the apparent digestion of essential amino acids in the hindgut was greater than that of non-essential amino acids. It is calculated that methionine and threonine may be limiting for the growth of calves given diets A and B, while dietary metabolizable energy intake was probably the first factor limiting the growth of calves on diet C.
Effect of storage temperature, storage duration and germination temperature on the dormancy of seed of Avena fatua L. and Avena barbata Pott ex Link
Authors: Paterson JG , Goodchild NA , Boyd WJR
Published: November 2004

Seed collected from genotypes of A. fatua and A. barbata naturalized in the northern, intermediate and southern latitudes of the temperate zone of Western Australia was tested for ecotypic variation under differing temperatures of summer storage and subsequent germination. The predominance of A. fatua in cereal crops is considered to be due largely to its well-developed seed dormancy. This characteristic is virtually absent in A. barbata, and this species does not norn~ally survive crop-land preparation. The level of seed dormancy and its rate of dissipation in both species is related to the geographic origin of the seed. That from the south of the temperate zone is more dormant than that from the north. Dissipation of dormancy in both species appears to be a function of time, temperature during storage or at germination having only a limited effect.
Nodulation of Stylosanthes guyanensis: prediction of Rhizobium effectiveness response with seed isozyme patterns
Authors: Robinson PJ , Date RA , Megarrity RG
Published: November 2004

Forty-nine introductions of S. guyanensis were tested against 22 strains of Rhizobium for effectiveness of the symbiosis in nitrogen fixation. A wide range of effectiveness between strains on individual accessions, and significant strain x accession interactions, were obtained. Two major groups of accessions were obtained on pattern analysis, a wide effectiveness response group with an average of 42% strains effective (containing 30 accessions) and a narrow response group with only 6% strains effective (19 accessions). The seed isozyme patterns (esterase and acid phosphatase) were also determined on the 49 introductions. Classification of these data also revealed two major groups containing 28 and 21 accessions which corresponded on a broad basis with the accessions containcd in Lhc wide and narrow effectiveness response groups respectively. The use of seed isozyme analysis as a guide to Rhizobium effectiveness response is proposed as a rapid screening technique for introductions of S. guyanensis.
The effect of atmospheric humidity on the yield and quality of soya bean
Authors: Woodward RG , Begg JE
Published: November 2004

Soya bean plants (cv. Lee) were grown at high and low atmospheric humiditiees in controlled environments. A constant level watering system ensured an adequate supply of water at all times. Bean yields decreased at the low humidity as a result of a reduction m pod number and thus bean number, which was only partly compensated by a small increase In bean weight The reduction In pod number was related to floret abortion rather than pod abortion, and was possibly a consequence of reduced photosynthate supply. The level of humidity did not affect the protein or oil content of the seed. The lower humidity also reduced the dry weights of stems and total tops and the number of nodes per plant. The humidity level before or after flowering alone did not affect bean yield, but the humidity from the start of flowering onwards did affect the number of beans per plant. The possible significance of the results for soya bean production In the Australian environment is considered.
The use of diphenylamine to protect apples from methyl bromide injury
Authors: Sproul AN , O'Loughlin JB , Terauds A , Hardisty S
Published: November 2004

Three experiments were conducted to explore the use of diphenylamine to prevent fruit injury resulting from fumigation with methyl bromide. Two were conducted in Western Australia on Granny Smith apples and one in Tasmania on Granny Smith and Crofton apples. The results showed clearly that diphenylamine either as a dip or as a wrap prevented methyl bromide injury, but oil-impregnated wraps did not.
Effect of calcium, pH and nitrogen on the growth and chemical composition of some tropical and temperate pasture legumes. II.* Chemical composition (calcium, nitrogen, potassium, magnesium, sodium and phosphorus)
Authors: Andrew CS , Johnson AD
Published: November 2004

The chemical composition of tops and roots of nodulated and non-nodulated plants of some tropical and temperate pasture legumes grown in sand culture is reported and discussed in relation to nodulation efficiency and dry matter production, and nutrient interaction. In most species, increasing pH raised the nitrogen concentrations in the tops of nodulated plants; calcium treatment had little effect. Increasing the calcium concentration of the nutrient solution from 0.125 to 2.0 mM markedly increased the calcium~ concentration in the tops of all species, but in the roots to only a minor extent. Concentrations in tops differed between species. Concentrations in the tops of modulated plants were increased as a result of increasing pH, particularly at the low calcium treatment and for those species sensitive to low pH (Glycine wightii, Medicago species). Increasing the calcium concentration lowered the magnesium concentration, but the total cation content was not significantly affected. In the tropical species, phosphorus concentrations in the tops were increased by reducing pH at both calcium treatments; values were higher at the low calcium treatment than at the high calcium treatment. Roots accumulated inore phosphorus than the tops. Differences in the response of the species cannot be directly related to their mineral composition. With respect to nodulation and dry matter production, it is considered that the pH is the dominant factor and operates in the nodule initiation phase and in subsequent nitrogen production.

_______________
*Part I, Aust. J. Agric. Res., 27: 611 (1976).
Canary coloration of wools: breed differences and their possible causes
Authors: Acharya RM , Singh M
Published: November 2004

The intensity of non-scourable yellow (canary) coloration, based on a visual score, was observed in a number of indigenous carpet-wool breeds, Rambouillet and Merino, and in the crosses of some of the indigenous breeds with Rambouillet. Among Indian breeds, those with dense fleeces showed more intense coloration than those with open fleeces. Exotic fine-wool breeds (Merino and Merino types) showed considerably less coloration than the native breeds. Rambouillet x Chokla crosses (half and three-quarter breeds) had less intense coloration (P < 0.05) than Chokla, the three-quarter breeds significantly (P < 0.05) less than the half-breeds. In contrast, the Rambouillet x Malpura half-breeds showed more intense coloration (P < 0.05) than the pure Malpura, though the three-quarter breeds showed coloration similar to that of the Malpuras. It is suggested that different modes of heat dissipation—a greater dependence on respiratory evaporative cooling in Merinos and on cutaneous evaporative cooling in native breeds—are responsible for the differences in intensity of fleece coloration between exotic and native breeds. Differences in coloration among native breeds appear to be due primarily to differences in fleece density. Differences between half-breeds and the respective native breeds appear to be due to the combined effect of the different modes of heat dissipation and diffcrences in fleece density: the increase in exotic inheritance results in greater dependence on respiratory evaporative cooling.
The effect and site of action of potassium upon magnesium absorption in sheep
Authors: Tomas FM , Potter BJ
Published: November 2004

The effect of potassium chloride infusion to the rumen or duodenum of sheep upon the absorption of magnesium from the stomach and intestinal regions has been examined. Three Merino ewes, each prepared with a cannula into the rumen and a re-entrant cannula into the duodenum, were offered a basal diet (control) which provided 46.3–51.1 mmoles magnesium and 299–320 mmoles potassium per day. Potassium chloride (500–800 mmoles/day) was infused continuously to either the rumen or duodenum. Digesta fluid flows were estimated from the dilution of a Cr-EDTA solution continuously infused to the rumen. Potassium infusion to either gastrointestinal site led to a comparable increase in the water intake, urine volume and levels of plasma and urinary potassium. Infusion to the rumen caused a marked increase in the potassium levels and a decrease in sodium levels in rumen fluid, as well as an increase in the rumen fluid to blood bioelectrical potential. No effect of treatment on digesta fluid flows was observed. Net magnesium absorption was lowered only when potassium was infused to the rumen, and the reduction was almost entirely due to reduced absorption of magnesium from the stomach. There was no consistent effect on absorption of magnesium from the intestines. Plasma magnesium levels were lowered by both the intraruminal infusion and, to a lesser extent, the duodenal infusion of potassium. The results indicate that although one consequence of potassium ingestion by sheep may be an enhancement of the urinary excretion of magnesium, the major effect on magnesium metabolism is a substantial reduction of absorption of magnesium from the reticulorumen.
Response to two-way selection for harvest index in two wheat (Triticum aestivum L.) crosses
Authors: Bhatt GM
Published: November 2004

A two-way selection experiment was conducted during 1974 and 1975 with two wheat (Triticum aestivum L.) crosses with a view to measuring the direct response of harvest index and its correlated response of grain yield. In the F2 generation, 10% selection intensity was applied for high as well as low harvest index and the selected populations were grown in the F3 generation. The progenies selected for low harvest index in the F2 generation gave low harvest index in F3 plants also, while those selected for high harvest index in the F2 generation segregated into high and medium harvest index in F3 plants. Simple and partial correlations of plant weight and grain yield with harvest index suggested a moderate to high positive association of grain yield with harvest index in the F3 generation. Estimates of heritability and gain from selection were high. The crosses under study provided evidence on the possible use of harvest index as a selection criterion for yield improvement in early segregating generations.
Survival of annual ryegrass (Lolium rigidum Gaud.) in a Mediterranean type environment. 1. Effect of summer grazing by sheep on seed numbers and seed germination in autumn
Authors: Gramshaw D , Stern WR
Published: November 2004

Annual ryegrass–subterranean clover pastures that produced about 5000 kg total dry weight per hectare and 23,500 ryegrass seed per sq metre in spring were grazed by sheep at different stocking rates during summer. Intensive stocking equivalent to about 3000 sheep days ha-1 reduced seed numbers by 20%. Under continuous grazing, about 70% of the seed produced in spring fell readily to the ground during summer. The remaining seed was firmly held in seed heads, and apparently sheep ate mainly this component. Less than 1% of the seed ingested was voided in the faeces. No significant changes in seed numbers over summer were observed in ungrazed pasture. Subsequently, at the break of season in autumn, germination of seeds was examined in situ near the soil surface. The summer grazing history of pastures influenced the percentage of seeds that germinated; more seeds germinated in heavily than in leniently grazed pastures. Whether the pasture was leniently or heavily grazed, there was little effect on germination of shed seeds. Seeds in seed heads were found to germinate more slowly than seeds shed to the soil surface. Seedling emergence in autumn was regulated mainly by the interrelationship between the germination rate of the seed population, depending on summer-early autumn rains, and the period for which favourable moisture conditions prevailed at the soil surface after rain began in autumn. In the field, temperature and light appeared to be unimportant in influencing germination at the break of season. Dynamics of seed and seedling numbers in annual ryegrass pastures in a Mediterranean type environment, particularly at the break of season, are discussed.
The seasonal abundance and control of light brown apple moth, Epiphyas postvittana (Walker) (Lepidoptera: Tortricidae), on grapevines in Victoria
Authors: Buchanan GA
Published: November 2004

This paper describes studies relating to control of Epiphyas postvittana (Walker), the major insect pest of grapevines in north-west Victoria. From 1970 to 1973, observations were made of the seasonal abundance and damage by E. postvittana in the absence of control measures. Larval populations were highest during spring, and declined to low levels during summer. Parasites caused c. 30% larval mortality, but did not prevent larvae damaging up to 19% of grape bunches at harvest. In drying varieties the actual loss was only about 1% by weight. Damaged grapes were liable to fungal infection during January and February, which resulted in further loss. During 1973–74 some commercially available selective insecticides were compared with standard recommendations for control of E. postvittana. The most effective treatment was lead arsenate or lead arsenate–TDE but the use of Bacillus thuringiensis or aminocarb could be justified if control of other vine pests is taken into consideration.
Fixation, accumulation, and distribution of nitrogen in a crop of Lupinus angustifolius cv. Unicrop
Authors: Farrington P , Greenwood EAN , Titmanis ZV , Trinick MJ , Smith DW
Published: November 2004

A lupin crop was sampled each week to measure nitrogen fixation by acetylene reduction assay and for determination of the total nitrogen content on the organs on each axis of the plant. Nitrogen fixation started 5 weeks after sowing, reached its maximum rate per plant at the beginning of flowering on the main axis, and ceased during the period of rapid grain filling, which was 4 weeks before maturity. Plants did not accumulate measurable quantities of nitrogen until 2 weeks after the start of nodular fixation as indicated by acetylene reduction. In the vegetative phase within each order of axes most nitrogen went to the leaves before they senesced. During the first half of the period of rapid grain filling, both the weight and the concentration of nitrogen in the grain increased at the expense of the vegetative components. Balance sheets for nitrogen content and the current proportional distribution of nitrogen are presented for three occasions at weeks 8-9, weeks 15-16 and weeks 18–19. Waterlogging greatly decreased acetylene reduction and plant growth.
Corrigendum - Fixation, accumulation, and distribution of nitrogen in a crop of Lupinus angustifolius cv. Unicrop
Authors: Farrington P , Greenwood EAN , Titmanis ZV , Trinick MJ , Smith DW
Published: November 2004

A lupin crop was sampled each week to measure nitrogen fixation by acetylene reduction assay and for determination of the total nitrogen content on the organs on each axis of the plant. Nitrogen fixation started 5 weeks after sowing, reached its maximum rate per plant at the beginning of flowering on the main axis, and ceased during the period of rapid grain filling, which was 4 weeks before maturity. Plants did not accumulate measurable quantities of nitrogen until 2 weeks after the start of nodular fixation as indicated by acetylene reduction. In the vegetative phase within each order of axes most nitrogen went to the leaves before they senesced. During the first half of the period of rapid grain filling, both the weight and the concentration of nitrogen in the grain increased at the expense of the vegetative components. Balance sheets for nitrogen content and the current proportional distribution of nitrogen are presented for three occasions at weeks 8-9, weeks 15-16 and weeks 18–19. Waterlogging greatly decreased acetylene reduction and plant growth.
The effect of sowing date on the growth and yield of three sorghum cultivars in the Ord river valley. II. The components of growth and yield
Authors: Williams WT , Boundy CAP , Millington AJ
Published: November 2004

Thirteen measurements were obtained from 59 successive sowings of three cultivars of sorghum. Principal component analyses showed that growth could be regarded as consisting of three largely independent components: crop density, total photosynthate, and extension. The correlations of these components with environmental measurements are examined. There is a high negative correlation between grains per head and heads per plot; grain weight is independent of crop density or spacing; the relationship between grain weight and number varies with the cultivar, attaining a high negative value for the hybrid RS610. Compared with sorghum grown elsewhere in the world, grain weights in the Ord are normal, but the number of grains per head is unusually low. This does not appear to be a high temperature effect, since in the dwarf cultivars higher maximum temperatures resulted in an increased number of smaller grains. It is suggested that African dwarf cultivars sensitive to day length might be more appropriate for the Ord than the American cultivars currently grown.
The growth of young peach trees following infection by the viruses of peach rosette and decline disease
Authors: Smith PR , Neales TF
Published: November 2004

The vegetative growth of young peach trees was reduced greatly in the growing season following a dual infection with Prunus necrotic ringspot and prune dwarf viruses which caused the disease known as 'peach rosette and decline'. Ninety-two days after bud burst, the dry weight and leaf area of cv. Elberta scions were reduced by c. 60% as a result of infection, while the reduction in cv. Golden Queen was about 93%. The latter cultivar thus appears to be the less tolerant of infection by this virus disease.
Parthenium weed (Parthenium hysterophorus L.): gas exchange characteristics as a basis for prediction of its geographical distribution
Authors: Doley D
Published: November 2004

Gas exchange studies in Parthenium hysterophorus L., a weed recently introduced into central Queensland, indicate that its limits of distribution may be very wide in the humid and subhumid regions of Australia. Under conditions of high leaf water potential, the maximum rate of apparent photosynthesis of cabinet-grown plants was 77 ng cm-2 sec-1, with a temperature optimum of 28°C. Gas phase diffusive resistances were very low and insensitive to photosynthetic photon flux density at high water potentials (–5.0 bars), but became greater and quite sensitive to photon flux as the leaf water potential approached –20 bars. At temperatures between 10 and 40°C, transpiration increased slightly, and the dark respiration rate was almost constant, owing to a steady and considerable increase in gas phase diffusive resistance with temperature. The control of gas exchange broke down at about 42°C, so that transpiration in the light and dark proceeded at equal rates, and dark respiration rates were very high. Gas exchange in P. hysterophorus appears to be no more sensitive to reduced water potential than it is in several favoured crop and pasture species, but the distribution of this weed may be limited by even brief exposure to very high temperatures, or by prolonged drought.
The effects of resting sheep after a long journey on concentrations of plasma constituents, post-mortem changes in muscles, and meat properties
Authors: Shorthose WR
Published: November 2004

After a 1110 km road journey, rams were rested either 18 hr with water available or 120 hr with feed and water before slaughter. Not all animals rested for 120 hr ate the feed offered. Animals rested for only 18 hr had less glycogen in the M. longissimus dorsi (LD) and liver at slaughter than those rested for 120 hr. The ultimate pH values of the LD (5.94) and M. semitendinosus (6.31) of rams rested for 18 hr were greater than those of the same muscles from animals that ate during their 120 hr rest period. Meat colour was darker in chops from animals rested for 18 hr than in those from animals rested 120 hr, although peak shear force values for this muscle did not differ between the two treatments.
The effects of high incubating temperature on the growth of the chick embryo
Authors: Thinh NX , Cumming RB , Thwaites CJ
Published: November 2004

During the second half of incubation, 112 eggs from White Leghorn hens and Leghorn x Australorp cocks were randomly allocated to four equal groups and incubated at 37.6° (control), 40.6°, 41.7° and 42.8°C respectively. On day 17, all eggs were candled, opened and their embryos were weighed. As incubating temperatures increased, embryonic mortality also increased (3.5, 0, 25.0, 50.0 % respectively, P < 0.01) and embryo weight decreased (18.5, 17.3, 13.0 and 11.7 g, P < 0.001). The effects of high temperature on embryonic mortality and growth of the chicken are very similar to those previously reported in sheep. This suggests the use of the avian embryo as a readily managed model in investigating the mechanism of heat action in both species.
Assessment of damage to annual pastures by the pasture cockchafer, Aphodius tasmaniae Hope, in South Australia
Authors: Allen PG
Published: November 2004

The larvae of A. tasmaniae cause damage to extensive areas of pasture in the higher rainfall areas of South Australia. At present there is no reliable information about the densities of larvae which can be treated economically. Experiments on damage assessment were conducted in naturally infested pasture. In the first experiment pastures were ungrazed by livestock. Available pasture dry matter from four pastures, sprayed with lindane to control larvae, was compared with dry matter from adjacent, untreated pasture. There were no differences in available pasture which could be attributed to A. tasmaniae at any of the sites. The results indicated that the apparent damage caused by A. tasmaniae was a combined effect of grazing livestock and larval feeding. Therefore, a second experiment was conducted in which the pastures were grazed evenly with livestock. In this experiment a significant difference in available pasture dry matter between treatments was found, and this could be attributed mainly to A. tasmaniae. The results suggested that this technique was suitable and could be extended to assess the damage to pasture caused by a wide range of densities of A. tasmaniae larvae.
Sheltering behaviour of lambing Merino sheep in relation to grass hedges and artificial windbreaks
Authors: Lynch JJ , Alexander G
Published: November 2004

This study extends previous findings that recently shorn, lambing ewes made extensive use of the shelter provided by hedges of a tall grass (Phalaris hybrid) and that the provision of such windbreaks was associated with a reduction in lamb mortality. The study compares phalaris hedges with fences of a polyethylene garden-mesh (Sarlon; 60% porosity) and examines the effect of different spacings between Sarlon shelters. The phalaris reduced wind speed over the lee 20 m to a greater extent than Sarlon. In contrast to the marked concentration of ewes immediately adjacent to the lee of the phalaris (0–2 m), ewes were dispersed over a greater distance (0-6 m) from the lee of the Sarlon; at night about 12% more of the flock were found within 6 m of the lee of the phalaris than within the same distance of the Sarlon. In addition to the proportion of shorn ewes that were expected to be in shelter on the basis of random distribution alone, c. 35% were found within 6 m of the shelter at night, and 15% during the day regardless of whether Sarlon shelters were 20, 40 or 80 m apart. Unshorn ewes made very little use of the shelters, and lambs from shorn and unshorn ewes made more use of shelters and particularly of the phalaris than their mothers. Ewes tended to congregate at one end of the paddock regardless of wind direction and the presence of shelter, which indicated a role for strategic selection of sites for shelters. As in the previous study, lamb mortality was lower in the sheltered than in the unsheltered group, especially amongst twins.