bluuebunny/crossref_metadata_2025 huggingface dataset:
The effect of frequent ejaculation in the ram on some semen characteristics
Authors: Salamon S
Published: November 2004

(1) Series of 13 ejaculates per day for 10 successive days were collected from each of five Merino rams. Every third ejaculate was examined for volume, density, and fructose and citric acid concentrations — 250 samples in all. (2) The mean fructose and citric acid concentrations were 596 and 91 mg% respectively. While the mean fructose concentrations differed significantly (P < 0.001) during the successive 10 days of collection, the citric acid concentrations did not. Both seminal constituents declined with ejaculates within days (P < 0.01 ; P< 0.001). There were significant declines in mean volume and density and an increase in mean reaction time with successive days and with collections within days (P < 0.001). Rams differed significantly in all characteristics examined (P < 0.001). (3) Multiple factor analysis revealed that three factors were mainly responsible for variances in the characteristics studied during the 10 days and within days of collection. The variances in characteristics contributed to by sequence of ejaculates in individual rams over the 10 days were: 68–96% for volume, 90–100% for density, 28–98% for reaction time, and practically nil for fructose and citric acid concentrations. There were marked ram differences in contribution of the sequence of ejaculates to the within-day variance in volume (0–90%), density (0–98%), citric acid concentration (0–98%, and reaction time (0–97%). The ejaculates collected had practically no contribution to the within-day variance in fructose concentration. (4) The rams with relatively low sexual response (long mean reaction time) tended to ejaculate semen of relatively high volume and with high concentrations of fructose and citric acid.
Energy costs of feeding activities and energy expenditure of grazing sheep
Authors: McCGraham N
Published: November 2004

The energy costs of standing, of rumination, of eating prepared meals, and of grazing were determined in laboratory experiments by indirect calorimetry. Sheep with body weights ranging from 30 to 110 kg were used. Energy expenditure due to standing amounted to 0.34 ± 0.02 kcal/hr/kg body weight. The energy cost of rumination was 0.24 ± 0.03 kcal/hr/kg. Rate of food intake varied from 60 g dry matter/hr with sheep grazing a poor sward to 800 g/hr with sheep eating hay, but in general this did not affect energy expenditure appreciably. The cost of eating prepared meals of either fresh herbage or hay was 0.54 ± 0.05 kcal/hr/kg body weight. It tended to be greatest when rate of food intake was greatest. Energy expenditure due to grazing was also 0.54 ± 0.05 kcal/hr/kg, irrespective of the type of sward and associated grazing behaviour. It is estimated that muscular work, mainly standing and eating, could account for nearly 40% of the daily energy expenditure of a sheep at maintenance, grazing a poor but level pasture, with drinking water available, and only 10% of that of a caged animal. Such a grazing animal could thus have requirements over 40% greater than those of a caged one. With sheep on hilly pasture or a long way from water, the cost of walking could become a major item.
The pathogenesis of footrot in sheep with reference to proteases of Fusiformis nodosus
Authors: Thomas JH
Published: November 2004

Preparations of cultures of Fusiformis nodosus, the causal organism of footrot in sheep, were tested for their ability to digest substrates of dermal and epidermal tissues. The preparations did not hydrolyse hyaluronic acid, chondroitin sulphate, or collagen. Weak elastase activity was demonstrated. Enzyme preparation 1 obtained from the supernatant fluid of liquid cultures during growth of F. nodosus, and enzyme preparation 2 obtained after growth had ceased, digested powdered sheep hoof in the presence of cysteine. Enzyme preparation 1 possessed two pH optima for hoof digestion, at pH values of 7.6 and about 10.5. Enzyme preparation 2 also possessed two optima, at pH 8.2 and at about 10.5. Hoof digestion by either enzyme preparation was enhanced by 4M urea with cysteine, particularly at pH 10.0. Hoof digestion by enzyme preparations 1 and 2 was not inhibited by iodoacetamide. Hoof pretreated with potassium thioglycollate or with performic acid was digested by both enzyme preparations 1 and 2 in the absence of cysteine. For these reasons, cysteine was considered to react with the substrate rather than with the enzymes. The digestion of preparations of amorphous, fibrous, and reduced and carboxymethylated hoof protein, for which cysteine was not required, supported this view, and indicated that cysteine exposed hoof proteins to the digestive action of F. nodosus proteolytic enzymes by sulphydryl transfer. Enzyme preparations 1 and 2 also disintegrated frozen sections of sheep hoof. This effect was greater at pH 10.0 than at 8.0 and in the presence of cysteine. When enzyme preparations 1 and 2 were injected into the skin of sheep at pH 8.0 and 10.0 together with cysteine, ulcers were produced in 24–48 hr. These were similar to the ulceration of the epidermis of the hoof in footrot.
The occurrence of a quiescent infection of stone fruits caused by Sclerotinia fructicola (wint.) Rehm.
Authors: Jenkins PT , Reinganum C
Published: November 2004

An infection of immature peach and apricot fruits by Sclerotinia fructicola (Wint.) Rehm. is described. Since infection results in macroscopically visible lesions it is proposed that this type of infection be known as "quiescent" rather than latent. Symptoms have been induced in immature apricots by inoculation with conidia of the fungus and, after a period of quiescence, progressive rots developed from such infections as the fruit ripened. The fungus was re-isolated from surface-sterilized material bearing quiescent infections. Cultural evidence, together with field observations, indicate that a quiescent infection occurs naturally in the orchard, particularly in a season of moderate to severe blossom infection. Fruit losses during a dry harvest period are ascribed in the main to the activation of quiescent infections during fruit ripening. The histology of the lesion is described. The response of the host to infection is variable, but always includes a more or less extensive collapse and necrosis of the epidermis and of one or more layers of the hypodermis. Periderm formation may be associated with the necrogenic reaction. The results of a spray trial demonstrate that some measure of control of quiescent infection can be achieved by applying eradicant sprays during blossoming, and thus provide circumstantial evidence that a proportion of such infections can be established during this period. The quiescent infection is compared with other host-pathogen combinations in which infection is followed by a period of latency or quiescence, and suggestions are put forward as to the factors governing quiescence. The concept of "latent contamination" is re-evaluated in the light of the evidence presented in the present paper. It is argued that conidia alighting on the fruit surface during the growing period are more likely to give rise to a quiescent infection than to survive to produce an infection of the ripe fruit.
Isoflavone mutations in subterranean clover. I. Their production, characteristics and inheritance
Authors: Francis CM , Millington AJ
Published: November 2004

Four isoflavone mutations of considerable biological and practical potential are described. Genetic evidence accumulated to date suggests the mutations to be simple recessives. A single gene can control the release of bound isoflavones. Single genes apparently also control the methylation of daidzein and genistein to formononetin and biochanin A respectively, and the development of isoflavones in normal quantities. Crosses between lines carrying the individual mutations lead to modified dihybrid Mendelian ratios.
The effect of age and dietary protein sounce on free amino acids, ammonia, and urea in the blood plasma of the calf
Authors: Leibholz J
Published: November 2004

The concentrations of most of the free amino acids in the blood plasma of the calf decreased with increasing age between 3 days and 24 weeks. This effect was significant for serine, proline, methionine, leucine, glutamine, lysine, and histidine while the concentrations of aspartic acid, glutamic acid, valine, cystine, and ornithine remained constant. Dried skim milk as a protein supplement in the calf's diet resulted in a higher concentration of free amino acids in the blood plasma than did meat meal. The relative proportions of the free amino acids in the plasma were related to their concentrations in the diet. Addition of methionine to calf diets increased the free methionine concentration in the blood plasma.
Life cycle of Babesia argentina (Lignières, 1903) (Sporozoa : Piroplasmidea) in the tick vector Boophilus microplus (Canestrini)
Authors: Riek RF
Published: November 2004

Babesia argeutina, a protozoan parasite causing tick fever of cattle in Australia, is transmitted by Boophilus microplus. Its development in this invertebrate vector is very similar to that recorded by Riek (1964) for Babesia bigemina. Many of the parasites occurring in the bovine erythrocytes are destroyed on ingestion but the early development in the lumen of the gut is uncertain. By about 36 hr, blunt, cigar-shaped forms, 7.2–1 3.8 µ by 2.6–5.6 µ, invade the epithelial cells of the gut and subsequent development is by means of multiple fission. This leads, by about 96 hr, to the production of mature vermicules which measure about 15.8 µ by 3.0 µ, with a range of 14.3–16.9 µ by 2.8–3.5 µ. At about this time vermicules enter the mature ova of the tick, and a further cycle of multiple fission in the gut cells of the developing larva gives rise to vermicules similar to those produced in the adult tick. The final cycle takes place in the salivary glands of the larva, and the forms infective to the vertebrate host appear 2–3 days and longer after larval attachment. Multiplication in this cycle is also by multiple fission and gives rise to comparatively small numbers of infective forms measuring about 1.5 µ by 1.0 µ. Not all ticks develop an infection even after engorging on blood with a high parasite density. Certain 'strains' of Boophilus microplus seem to be more susceptible to infection than others. Heavy mortalities occurred in many ticks after ingesting blood with a parasite density of 5% or higher.
Energy expenditure and respiratory activity of sheep during feeding
Authors: Young BA
Published: November 2004

Energy costs of feeding and respiratory changes during the ingestion of prepared rations were measured in experiments on penned sheep. Feeding energy increments per kilogram liveweight (increased energy expenditure attributable to the act of eating) ranged from 5.3 to 12.4 cal/min. Differences between sheep and between rations were not significant. Energy costs of eating (increased energy expenditure per gram of ration ingested) varied with the type of ration. A concentrate ration was ingested at an energy cost (per kg liveweight) of 0.3–0.6 cal/g ration, whereas chaff rations cost 1.2–1.9 cal/g ration. A marked reduction in respiratory frequencies and respiratory minute ventilations occurred during feeding whenever the pre-feeding respiratory activity was elevated due to the ambient temperature. When the respiration was eupnoeic before feeding there was a slight increase with feeding. While sheep were eating, respiratory frequencies ranged between 20 and 40 per minute and respiratory minute ventilations from 4.5 to 8.4 litres.
The special senses in grazing animals. II. Smell, taste, and touch and dietary habits in sheep
Authors: Arnold GW
Published: November 2004

The influence of impairment of the senses of smell, taste, and touch, either singly or in combination, on the dietary habits of sheep was studied in a series of experiments. Marked changes in the relative acceptability of species, or strains of a species, occur when each of these senses is impaired. Significant increases and decreases in herbage intake are obtained on pure stands of species as a result of sensory impairment. All the senses are of some importance when all pasture conditions are considered. In specific situations, however, a single one of the senses is often of paramount importance. Impairment of all three senses did not alter animal productivity over the year, which indicates that the special senses are not always critically involved in the total intake of nutrients. An exception is under prolonged dry pasture conditions.
The relationship between temperature fluctuations and the softening of hard seeds of some legume species
Authors: Quinlivan BJ
Published: November 2004

Hard seeds of subterranean clover (Trifolium subterraneum L.) of the Geraldton and Bacchus Marsh strains, and of West Australian blue lupin (Lupinus varius L.), were subjected to various daily fluctuating temperatures within the normal summer environmental range (15–75°C). The main factor determining the rate of softening of the hard seeds was the maxinlum temperature of the fluctuation. Provided the temperature changed by some 15°C , the amplitude of the fluctuation did not appear to be a critical factor. The softening of hard seeds of any particular species did not commence until the amplitude of the temperature fluctuation, or the maximum temperature, reached a certain level, which in turn varied with the species. Beyond this level the rate of softening increased with increasing fluctuations to a point where the rate became very rapid, and thereafter wider fluctuations or higher maximum temperatures did not give significant increases.
The effects of sand type and fine particle amendments on the emergence and growth of subterranean clover (Trifolium subterraneun L.) with particular reference to water relations
Authors: Roberts FJ
Published: November 2004

Twelve types of sandy soil exhibited considerable differences in ability to promote emergence? of subterranean clover when compared under suboptimal soil water conditions. These differences resulted from interactions between soil water relations, mechanical impedance, and aeration. Water requirements for satisfactory emergence of subterranean clover in a coarse sand were studied in the laboratory. Highest emergence was achieved when a water content of 10% by weight (–10 cm water potential) was maintained for at least 4 days. Very little emergence occurred when the water content was maintained at 2% by weight ( –120 cm water potential). A sustained water content of about 10% for 4 days was infrequently achieved in the field under natural rainfall conditions. Initial establishment and subsequent maintenance of subterranean clover on coarse sands in the field can be critically limited by the effects of poor soil water relations on emergence. Incorporation of 2.5% by weight of three fine particle amendments in the topsoil produced spectacular improvements in emergence and establishment. Fly ash was superior to clay, which in turn was superior to finely ground silica. This was due in part to beneficial effects on nodulation and growth. Incorporation of fine particle material in the soil layer below the seed zone required less material to produce the same response as uniform mixing throughout the topsoil.
Calcium nutrition in relation to the occurrence of internal browning in Brussels sprouts
Authors: Millikan CR , Hanger BC
Published: November 2004

Brussels sprouts, cv. Long Island, grown in sand cultures supplied with either normal or low-calcium nutrient solutions, were used to study the relationship between internal browning of sprouts and the calcium regime of the plants. The interaction of ammonium, magnesium, and potassium ions with calcium nutrition, and the susceptibility of four locally selected strains of Brussels sprouts to the disorder, were also investigated. No symptoms, in either the sprouts or the growing points, were found in plants grown under normal calcium nutrition, but each of the low-calcium treatments, irrespective of other cations, induced a significant amount of internal browning in sprouts. The incidence was greatest in the low-calcium high-magnesium, and least in the low-calcium high-ammonium treatments. Calcium deficiency symptoms of the growing points were most severe in the low-calcium high-magnesium treatment, and only this treatment significantly reduced plant yield. Internal browning occurred in the four strains when grown under the low-calcium high-magnesium treatment. Two strains (Bepi and original early) were more severely affected and developed symptoms earlier than the other two (Sartori and mid-season). However, the Sartori strain was the only one in which low calcium nutrition reduced yield. The calcium content in the sprouts decreased from the wrapper to the meristematic region. In leaves, the calcium content was highest in the leaf margin in all strains except mid-season. Low calcium nutrition greatly reduced the calcium content in sprouts and leaves.
Symbiotic characteristics of Rhizobium meliloti: and appraisal of the systematic treatment of nodulation and nitrogen fixation interactions between hosts and Rhizobia of diverse origins
Authors: Brockwell J , Hely FW
Published: November 2004

The symbiotic properties of 42 isolates of Rhizobium meliloti collected from widely separated sites in the upper basin of the Darling River were tested in bacteriologically controlled culture with 18 species and varieties of Medicago, three species of Melilotus, and one species of Trigonella. Seven strains of Rh. Meliloti of commercial interest were included in the experiments for comparative purposes. Nodule formation occurred on all plants in 889 out of 974 symbiotic combinations examined. Only Medicago laciniata (L.) Mill, among the hosts and the isolate from M. laciniata among the rhizobia exhibited distinctive nodule formation behaviour. Nitrogen fixation occurred in 637 combinations. On the basis of nitrogen fixation, eight groups of Rh. Meliloti were recognized; there were nine host groups. The groups could be arranged in an interlocking pattern of increasing host and bacterial specificity. These results, which modified to a small degree the bacterial and host groupings previously reported, strongly suggested that the pattern will be widely applicable to Rh. meliloti of diverse origin. In general, the isolates examined were promiscuous and 24 were capable of effective symbioses in association with 10 or more of the hosts. M. laciniata, Trigonella suavissima Lindl., and Medicago rugosa Desr. were the hosts most highly strain-specific in their requirements for nitrogen fixation, and Medicago sativa L. was the most promiscuous. A system for classifying host species into compatibility groups is proposed.
The rates of production of volatile fatty acids in the rumen. IV. Individual and total volatile fatty acids
Authors: Weller RA , Gray FV , Pilgrim AF , Jones GB
Published: November 2004

(1) In sheep fed at 12-hr intervals on roughage diets (lucerne and wheaten hay) total volatile fatty acid production in the rumen has been measured by an isotope dilution procedure based on the infusion of a single 14C-labelled volatile fatty acid. (2) Total and individual acid production has been measured through the infusion of a mixture of 14C-labelled acids in which the proportions of individual acids were such that transfers of 14C by interconversions between the acids were balanced. (3) The findings support the view that the mixture of acids produced in the rumen is similar in composition to that present in the rumen fluid throughout the feeding cycle. Consequently it was possible to determine the production of individual acids by a relatively simple procedure requiring only the infusion of a single 14C-labelled acid and measurement of the concentration of 14C in a composite sample of the acids in the rumen fluid collected throughout the feeding cycle. This procedure is considered suitable for routine use; automatic sampling of rumen fluid still further reduces the work involved. (4) The infusion of certain mixtures of 14C-labelled fatty acids showed that the composition of the acid initially formed in the rumen was acetic 77–83%, propionic 15–18%, and butyric 1–7% according to the diet given and the time elapsed after feeding. From 50 to 80% of the butyric acid in the final volatile acid product was formed from acetic acid. Degradation of 14C-labelled butyrate formed from [1-14C] acetate in the rumen showed 93% of the 14C to be nearly evenly divided between carbon atoms C1 and C3.
Competition for light and its effect on leaf and spikelet development of wheat plants
Authors: Puckridge DW
Published: November 2004

The effect of changes in the light environment of wheat plants at different stages in their growth was examined by growing single plants in tubes and changing the spacing of the tubes (population density) during development. Individual leaves on the main stem were reduced in both area and weight by transfer of the plants from high density to low density during the period from initiation of growth of the leaf on the apex to its appearance above the sheath. The number of fertile spikelets per ear was increased by transfer to low density in the period between formation of double ridges and ear emergence. It is suggested that the potential for grain yield of a wheat ear is affected by the light environment of the shoot at any stage before ear emergence.
The effect of feeding on Leucaena leucocephala (Lam) de Wit. on reproduction in rats
Authors: Joshi HS
Published: November 2004

In separate experiments, mature rats were either given a ration containing L. leucocephala leaf meal at 15% or 7 3% level, or dosed orally each day with water extract of the leaf meal before and during the breeding period. At the 15% level, the food intake of the rats was greatly reduced, and they showed general symptoms of inanition. All the females were infertile and the males showed reduced libido and fertility. In the other experiments the majority of the females conceived, but on autopsy it was observed that they had a significantly larger proportion of foetuses dead and undergoing resorption as compared with those of the control group. The results suggested that the toxic material in L. leucocephala, probably mimosine, produced infertility in the rat by reducing the food intake; when food consumption was adequate for reproductive function, the toxic material caused a high incidence of foetal death and resorption.
Effects of light, temperature, and rate of desiccation on translucency in wheat grain
Authors: Parish JA , Halse NJ
Published: November 2004

Wheat grain was harvested at maximum dry weight and dried under various conditions in the laboratory. Results showed that opaque grain was produced by fast drying; translucency developed with slow drying. The effect of various temperatures when drying rate was constant was also measured. It was found that translucency developed more at high temperatures than at low temperatures. There was little "mottling" despite the wide range between treatments from entirely opaque to fully translucent grain. Drying techniques were found whereby grain samples different in texture but identical in other respects can be prepared. In other experiments wheat plants were grown in controlled light and temperature conditions during the grain-filling period. Results showed that at this stage low temperature and low light intensity favoured the development of translucency.
The nature of the perennial response in Mediterranean grasses. II. Senescence, summer dormancy, and survival in Phalaris
Authors: McWilliam JR
Published: November 2004

Adaptation to summer drought has been one of the major factors influencing the life cycle of the Mediterranean grasses. The nature of this adaptation has been studied by comparing the behaviour of a typical perennial, Phalaris tuberosa, with a closely related annual species P. minor, under simulated summer drought conditions. One of the most important factors controlling the plant survival of these two species is the difference in the rate and pattern of senescence after flowering under the influence of moisture stress. In the annual, senescence is rapid and complete, but in the perennial it is retarded, and function is retained in certain organs, including the lower stem and root system, throughout the summer stress. This permits survival of dormant buds which contain the meristems vital for regrowth in the autumn. Another feature which may be important in the perennial is the limited carbon assimilation by the dormant culms during the summer which contributes a source of energy for the maintenance of root activity, and for the regeneration of dormant buds. The evidence suggests that these factors may be of general significance, and could well form the basis of the perennial response in other Mediterranean grass species.
Developmental growth and body weight loss of cattle. II. Dissected components of the commercially dressed and jointed carcass
Authors: Seebeck RM , Tulloh NM
Published: November 2004

The effects of developmental growth and of body weight loss on the carcass composition of Angus steers, as measured by dissection of butcher's joints, are described. Two groups of steers were used: group A, which grew continuously, and group B, which grew like group A and was then subjected to a period of weight loss before slaughter. Animals in both groups were killed at the same body weights. Statistical analysis consisted of analyses of covariance of weights of components converted to logarithms.The proportions of muscle and bone decreased significantly as carcass weight increased, while the proportions of all fat components (particularly subcutaneous fat and kidney and channel fat) increased. Developmental growth also influenced the distribution of the components in the carcass, particularly muscle, subcutaneous fat, and intermuscular fat. These changes in weight and distribution of components appeared to be detrimental to carcass value per unit weight. During body weight loss, the weights of bone and of connective tissue remained relatively constant, although with bone the rate of change varied significantly with the size of the animal before weight loss. All other components lost weight, approximately reversing the pattern of development during body weight increase (as estimated from the group A animals). The muscle content of the group B animals was, however, significantly lower than in group A animals at the same carcass weight. Kidney and channel fat also tended to be lower in group B than in group A, but this depended on the size of the animal before undergoing body weight loss. When all fat tissues were considered together, group B carcasses were only slightly lower in fat content than group A carcasses at the same carcass weight, and this difference was not statistically significant. Changes in the distribution of dissected components were also shown to occur with body weight loss. The changes in both weight and distribution of the dissected components appeared to be detrimental to carcass value per unit weight.
Undernutrition of the Merino sheep and its sequelae. I. The growth and development of lambs following prolonged periods of nutritional stress
Authors: Allden WG
Published: November 2004

The growth of Merino lambs was arrested for periods of up to 400 days at different stages of early post-natal life, and long after the restoration of a normal diet the sequelae to these treatments were measured in terms of growth, form, feed intake, feed utilization for weight gain, and the eruption of the permanent incisors. None of the restrictions impaired the capacity of the sheep to resume normal growth, and although the most severe handicap (growth arrested at 15 kg weight for 400 days) had as its sequel a smaller sheep at 3 years of age this effect was not statistically significant. The impetus to grow was more closely related to somatic development than to chronological age. However, the eruption of the permanent incisors was associated more with age than with size, although the relationship was not a close one. In other respects the normal pattern of allometric growth was undisturbed. Feed consumption and feed utilization for weight gain were in the long term unaffected by the treatments imposed, although minor deviations from the general pattern were observed during the early part of the recovery period.
Survival and seasonal germination of seeds of Avena fatua and A. ludoviciana
Authors: Quail PH , Carter OG
Published: November 2004

The effects of soil type, temperature, and moisture on the survival and seasonal germination of seeds of A. fatua and A. ludoviciana, buried at five depths in the soil, were studied in a glasshouse experiment. Seeds of both species germinated only when mean weekly minimum temperatures were below 20°C and mean weekly maxima below 28°. A. fatua germinated better than A. ludoviciana in the 20–30° range and was therefore the dominant species in autumn germinations of wild oats. Both species germinated throughout winter. Only 30% of the seeds sown produced seedlings. Of these 90% emerged in the first year after seeding and the remainder in the second year. Only 2% of the seeds sown remained viable after 18 months. The depth at which the seeds were buried, seed type, soil type. and moisture regime all affected the survival of seeds and the percentage that produced seedlings. An explanation is offered for the dominance of A. ludoviciana in the northern wheat-belt of eastern Australia.
Cervical mucus measurement in ovariectomized ewes as a bioassay of synthetic and phyto-oestrogens
Authors: Lindsay DR , FrancisC M
Published: November 2004

Increases in weight of cotton swabs placed into the anterior vagina were used as a measure of cervical mucus production in ovariectomized ewes. Dose response lines were obtained from graded doses of stilboestrol. Pretreatment with a series of progesterone injections was necessary for significant responses. Daily doses of 5 mg of progesterone prior to feeding resulted in a shorter period of response than doses of 10 and 20 mg. A bioassay of three strains of Trifolium subterraneum L. (cv. Dinninup, Dwalganup, and Woogenellup) and Lolium rigidum Gaud. with cervical mucus measurement showed significant differences in oestrogenic activity. Such differences appeared to be related to the formononetin content of the pastures. Responses were evident 1 day after the commencement of feeding and did not change on the second day. Highest precision in the calibration of stilboestrol responses was obtained when log mucus weight was regressed on log (dose (µg) + l). Indices of precision were comparable with the best published for other forms of sheep bioassay.
Brown rot of stone fruits on the Murrumbidgee Irrigation Areas. II. Aetiology of the disease in Trevatt apricot trees
Authors: Kable PF
Published: November 2004

Blossom blight is of economic importance in apricots on the Murrumbidgee Irrigation Areas (MIA), but fruit rot is not. Monilinia fructicola generally does not overwinter effectively in apricot trees in the MIA, the inocula for primary infections coming from nearby peach plantations. Blighted blossoms in apricot trees, which flower a week before peaches, may provide inoculum for blighting of flowers in the latter crop. In apricot trees, unlike peach, there is a continuous infection chain from flowering till harvest. Inoculum may pass from apricot to peach in December and January, thus bridging a gap in the infection chain in peach. The infection chain in apricot is described. Latent and quiescent infections were observed. The implications of the exchange of inoculum between peach and apricot are discussed.
The effect of antibiotics on ammonia accumulation and protein digestion in the rumen
Authors: Hogan JP , Weston RH
Published: November 2004

A study was made of the feasibility of using antibiotics to reduce ruminal deamination of protein that comprised 27% of the organic matter in a diet of lucerne hay and casein. Six sheep were each dosed with a different antibiotic. At the levels given, penicillin and erythromycin reduced rumen ammonia levels by about 35%, but also reduced food intake. Chloramphenicol reduced rumen ammonia by about 50% but neomycin, oxytetracyclene, and streptomycin had little effect.When all six sheep were subsequently dosed with chloramphenicol at 1 g/day the levels of rumen ammonia were reduced only to 85% of the control. The antibiotic had little effect on the extent of digestion of protein, organic matter, and cellulose, both in the stomach and in the whole alimentary tract, and on parameters associated with the movement of digesta through the stomach The quantity of nitrogen passing from the stomach in forms other than ammonia was 52–54% of intake during both the control and treatment periods. Much of this nitrogen probably passed from the stomach in the form of microbial protein, which indicated that the dietary protein was extensively digested. In consequence of the loss of nitrogen from the stomach, the protein apparently digested in the intestines was equivalent to only about 14.5 g/100 g digestible organic matter.
The net energy value of artificially dried subterranean clover harvested before flowering
Authors: McC Graham N
Published: November 2004

Subterranean clover (Trifolium subterraneum L. cv. Clare) was harvested before flower emergence and dried rapidly without heating. Each of four adult sheep was given the dried clover at rates of 200, 600, 1000, and 1400 g/day in four successive fortnights and was finally fed ad libitum for 1 month. Energy, nitrogen, and carbon balances and body weight changes were measured. The fasting energy losses of the sheep were determined at the end of the experiment. The hay contained approximately 27% crude protein, 14% crude fibre, and 3% lignin (dry matter basis) and was eaten avidly by the sheep. Voluntary consumption ranged from 1400 to 2100 g dry matter/day, and maximum balances were 2080 kcal and 17 g nitrogen/day. Digestibility of energy was 78% at the lowest level of feeding and 74% at the highest. Cell wall and cell contents were respectively 74 and 82% digestible. Energy losses in methane were unusually low (7–11% of digestible energy) whereas losses in urine were unusually high (12–21%). The net result was that metabolizable energy was a lower fraction of digestible energy than for most forages, e.g, it was c. 77% at maintenance instead of the normal 82%. Net availability of metabolizable energy was 84% between fasting and half maintenance, 69% between fasting and maintenance, and 54% above maintenance. The value of this clover per gram was in keeping with its chemical composition and digestibility; its exceptional value as a feed was due to the large amounts of digestible energy which the sheep took in when fed ad libitum.
The response of subterranean clover (Trifolium subterraneum L.) to foliar applications of phosphorus
Authors: Bouma D
Published: November 2004

Subterranean clover plants were grown in river sand or in culture solutions with and without phosphorus. Some phosphorus-deficient plants were sprayed once every 2–3 days with solutions (pH 2.5) of several phosphorus compounds at various concentrations, with and without wetting agents. Dry weights of tops and roots were significantly increased by most spray treatments compared with control plants grown without phosphorus. Foliar applications of 50 mM phosphoric acid solutions, containing little or no wetting agent, generally gave the greatest response. In the first experiment the plant dry weight in the best spray treatment was twice as high and in the second experiment 3.5 times as high as in the controls without applied phosphorus. In these spray treatments plant dry weight was no more than 40% of that in the control treatment receiving root phosphorus. Two days after application of 32P (solution pH 5.5, 0.01 mM phosphate) to the centre leaflet of either the first or the fourth trifoliate leaf, 70% of the tracer could be removed by washing with 20 ml water. Seven days after application of the tracer the treated leaflet of the first or the fourth trifoliate leaf still contained 77 or 70% respectively of the amount absorbed by the plant. In another experiment, in which 32P was applied in a 30 mM H3PO4solution at pH 2.5 or 5.0, washing of the treated leaflet 2 days after application removed 42 and 60% of the tracer respectively. Seven days after application the treated leaflet contained 28 and 34% respectively of the residue after washing. Relatively slow rates of uptake of phosphorus applied to the leaves were considered to be at least partly responsible for the poor growth responses compared with phosphorus applied to the roots. It was concluded that foliar applications of phosphorus offered little scope as a practical means of hastening the recovery from phosphorus deficiency.
Calcium requirements of plants
Authors: Loneragan JF , Snowball K
Published: November 2004

Calcium concentrations in the tops and roots of 30 grasses, cereals, legumes, and herbs were examined for plants grown over a wide range of calcium concentrations (0.3 to 1000 µM) which were maintained constant in flowing culture solutions of pH 5.7. When plants were grown continuously in solutions of constant concentration, the relation between the calcium concentration in tops and the yield generally showed two regions. Increasing solution calcium concentrations from 0.3 to 2.5 µM increased the yield greatly, while calcium concentrations in the tops remained constant. By contrast, increasing solution concentrations from 10 to 1000 µM markedly increased concentrations in tops but in most species had relatively small effects on yield. At luxury calcium supply the concentrations in herb and legume tops were very much higher than those of grasses and cereals and were surprisingly similar to those of the same species grown in soil in the field. That calcium concentration in plant tops which remained constant while yield increased substantially is believed to indicate the minimal functional requirement of the tops for calcium. The average functional requirements of herb and legume tops (0.1–0.2% dry weight) were generally much lower than previously reported but were about twice those of grasses and cereals (0.05–0.1%). With the exception of Lupinus spp., no legume or herb had functional calcium requirements as low as those of any grass or cereal. When plants were transferred from 1000 to 0.3 µM calcium concentrations, they developed calcium deficiency symptoms and grew less than plants which had one-third to one-tenth the calcium concentrations in their tops but which had been grown continuously in solutions of low and constant concentration (2.5–10 µM). Excess calcium accumulated in the old leaves during luxury calcium supply but was not mobilized when plants were transferred to calcium-deficient solutions. It is suggested that variation in the conditions of calcium supply under which calcium deficiency develops partly accounts for the wide range of critical values used by various workers to diagnose deficiency in plants.
Production of volatile fatty acids in the sheep caecum
Authors: Faichney GJ
Published: November 2004

Acetic, propionic, and butyric acids labelled with 14C were infused into the caecum of continuously fed sheep. The specific activity of the volatile fatty acids (VFA) in the caecum was determined at intervals during the infusion. The production rate was calculated by isotope dilution from the results of those experiments in which steady state conditions were obtained. Substantial interconversions occurred between the fatty acid fractions. The total production of VFA was about 440 mmoles/day, equivalent to 125 kcal/day or 5.3% of the animal's digestible energy intake.
Influence of a gene causing hardness on the milling and baking quality of two wheats
Authors: Symes KJ
Published: November 2004

Near-isogenic lines of Falcon, a hard wheat with good baking quality and high milling extraction, and Heron, a soft wheat of medium baking quality and rather low milling extraction, were produced differing only in the gene which determines hardness as measured by the particle size index. It is shown that the superiority of Falcon in milling extraction, loaf texture, and dough handling characteristics is very strongly associated with the gene which causes it to be a hard wheat. While Falcon generally has a loaf volume superior to that of Heron, if the genetic background of two wheats is identical except for hardness, soft wheats have higher loaf volumes. Because these three variables, which largely constitute total loaf score, are not all favoured by the same particle size index, total loaf score is less clearly influenced by hardness. Nevertheless hard wheats are always superior to, or not significantly different from, soft wheats of the same pedigree in this respect. This work points out the difficulty of producing really good quality soft wheats but on the other hand shows that soft wheats can easily be improved in at least some features of baking quality by the simple process of making them hard.
A study of merino sheep grazing a bladder saltbush (Atriplex vesicaria) –cotton-bush (Kochia aphylla) community on the riverine plain
Authors: Wilson AD , Leigh H , Mulham WE
Published: November 2004

A study was made of Merino sheep grazing a bladder saltbush (Atriplex vesicaria Hew. ex Benth.)–cotton-bush (Kochia aphylla R.Br.) community set stocked at three stocking rates (2.5, 1 .2, and 0.6 sheep/hectare) over a 3-year period. In spring the sheep preferred the perennial grass Danthonia caespitosa Gaudich. and the annuals Medicago polymorpha L. and Vulpia myuros (L.) K. C. Gmel. to the more abundant A. vesicaria. From summer to early winter the diet consisted mainly of A. vesicaria with the proportion of dead matter and Medicago burr increasing as the availability of A. vesicaria decreased. Seasonal fluctuations in wool growth were evident at all three stocking rates. Maximum wool growth rates occurred in spring when the nitrogen content (2.3%) and in vitro digestibility (65%) of the forage eaten was high. During autumn and early winter values for nitrogen (1.4%) and digestibility (50%) were lower and wool growth was at a minimum. At 0.6 sheep/ha animal productivity was maintained and there was little decline in the A. vesicaria population during the 3 years. Grazing eliminated all the A. vesicaria from the pasture stocked at 2.5 sheep/ha, and 98% at 1.2 sheep/ha. At these higher stocking rates the pasture proved incapable of maintaining the sheep for the 3-year period. The inability of A. vesicaria to recover after heavy or complete defoliation by grazing demonstrates the necessity of adopting a low stocking rate if the bush is to be retained.
The effects of plant density and frequency of cutting on the growth of cocksfoot (Dactylis glomerata L). I. The production of vegetative and reproductive tillers
Authors: Knight R
Published: November 2004

To study the effects of density and cutting frequency on the reproductive phase of cocksfoot (Dactylis glomerata L.) the plants of a clone were established on a geometric scale at nine spacings ranging from 4 to 17 in, between plants, which provided densities from 9 plants to 0.5 plant per sq ft. The plants were cut every 2, 4, or 8 weeks or cut once at the end of the growing season. The cut tillers were classified as vegetative or reproductive (elongating and heading). The number of vegetative tillers per plant was reduced by high density in all treatments. A change in cutting frequency from every 8 to every 4 weeks had little effect on numbers but cutting every 2 weeks led to a large reduction in numbers. The reproductive tillers were affected by the treatments much more than the vegetative tillers. At most densities, more reproductive tillers were produced by the regularly cut plants than by the plants cut once at the end of the season. The increase was attributed to destruction of the apical dominance of early reproductive buds that inhibit the development of further reproductive tillers. Very frequent cutting and high density delayed the incidence of the reproductive phase for many weeks. The optimal density for the production of reproductive tillers changed with time. It was often lower than for vegetative tillers.
Utilization by sheep of casein administered per duodenum at different levels of roughage intake
Authors: Egan AR
Published: November 2004

The apparent digestibility of casein infused per duodenum at two levels (providing 3 or 6 g nitrogen per day) was between 90 and 105%. The efficiency of retention of casein nitrogen was investigated at three levels of roughage intake and the effects of level of nitrogen and level of roughage upon nitrogen retention in wool and in tissues other than wool were studied. Casein administration per duodenum resulted in an increased rate of digestion of cotton threads suspended in the reticulorumen, which indicated effective recycling of nitrogen. Actual rates of digestion were lower at higher roughage intakes. Possible reasons for this are discussed. At each level of roughage intake, casein administration led to increased nitrogen retention, the partial efficiency of retention of the added nitrogen being 56-85% for the first 3 g of casein nitrogen and 22-32% for the second 3 g. At a given level of casein, retention and partial efficiency of retention were increased by increased roughage intake. At low levels of roughage intake, the increase in wool nitrogen retention as a response to casein supplements was as great as at higher levels of roughage intake. Wool nitrogen retention was increased by 30%, from about 1.0 to 1.3 g/day, for the first 3 g of casein nitrogen, with a 10% partial efficiency of incorporation of added nitrogen into wool. The second 3 g of casein nitrogen led to a smaller additional increment in wool nitrogen retention, with less than 5% partial efficiency of incorporation of added nitrogen into wool. Increases in the level of roughage intake did improve the partial efficiency of retention of nitrogen in tissues other than wool, from 50 to 75% for the first 3 g of casein nitrogen, and from 15 to 30% for the second 3 g. This effect was not accompanied by any decrease in the partial efficiency of incorporation of administered nitrogen into wool.