bluuebunny/crossref_metadata_2025 huggingface dataset:
Jonathon spot – Three factors related to incidence, fruit size, breakdown, and seed numbers
Authors: Martin D , Lewis TL , Cerny J
Published: November 2004

Observations are reported which show that: (1) There is an interaction between the disorders Jonathan spot and breakdown. There is a negative correlation between them, but the same fruits tend to be susceptible to both disorders. (2) In the absence of other disorders there is a positive intercorrelation between percentage Jonathan spot, mean fruit size, and mean seed number both within and between trees. (3) In the one fruit size group on a tree, fruits with Jonathan spot have a higher mean seed number per fruit than sound fruit, and the seeds have a greater tendency to germinate. (4) Within trees, a thinning treatment which produces fruit of differing sizes but with the same seed number does not alter the percentage Jonathan spot. Between trees, a thinning treatment which produces fruit of the same size but a differing seed number results in differing levels of Jonathan spot.
Studies on the artificial insemination of Merino sheep. I. The effects of frequency and season of insemination, age of the ewe, rams, and milk diluents on lambing performance
Authors: Salamon S , Robinson TJ
Published: November 2004

(1) Results of large-scale artificial insemination of Merino sheep (2346 ewes) on a private stud are presented, together with data for seven factorial tests designed to determine effects on fertility, following insemination at one or two successive oestrous periods, of season of insemination, milk diluents, age of ewe, individual ram, and frequency of insemination within a single oestrous period. (2) Insemination in the autumn is more effective than in the spring (79.7 v. 54.7 % of inseminated ewes lambed to insemination over two cycles; P < 0.001). (3) Results for maiden ewes in autumn or spring are 15–20% less than those for older ewes (P < 0.05 to < 0.001). (4) Ewes inseminated with semen of rams producing semen of indistinguishable quality, as gauged by standard field methods, may differ in fertility at a single insemination (P <0.01), but this difference disappears if ewes which return are inseminated by semen of the same rams at the next oestrous period. (5) Dilution of semen to 1.4 with heated cow milk – skim or whole – does not depress fertility. (6) Ewe-milk diluent depresses fertility following a single insemination (68.6 v. 47.3%; P< 0.01). (7) Insemination twice in the one oestrous period may increase fertility by 8–9% (70.3 v. 60.9%; P, N.S.). Such an increase is not worth the additional effort. (8) Fertility with diluted semen is comparable with that reported from eastern and central Europe, provided that ewes are inseminated during the autumn.
The effect of soil-water stress on the absorption of soil phosphorus by wheat plants
Authors: Fawcett RG , Quirk JP
Published: November 2004

A study of the effect of soil-water stress and phosphorus level on the efficiency of phosphorus absorption (micrograms phosphorus per milligram oven-dry root per day) and growth by young wheat plants grown on a lateritic podzolic soil showed that absorption was not affected by increasing soil-water stress, provided the plants were not damaged by wilting. In experiments where the water-stress treatment was imposed for only a few days it was found that the rate of phosphorus absorption was reduced after the plants had been subjected to a period of wilting. The results indicate that available soil phosphorus was derived mainly from fine pores undrained at suctions approaching 15 atm. The concentration of available phosphate in these pores may have been considerably higher than earlier estimates of the phosphate concentration in the soil solution. The absorption of phosphorus increased with increasing soil phosphorus potential for all levels of water stress.
The hair follicle population of cattle in relation to breed and body weight
Authors: Turner HG , Nay T , French GT
Published: November 2004

Hair follicle densities were studied in 330 cows sampled once, and 460 calves sampled twice at different ages. The calves were sampled at times varying in 2-month steps between birth and 22 months of age. Follicle density on the midside decreased with increasing body weight within animals according to a power of body weight very close to two-thirds. It is shown that data on follicle density, even from animals in the same environment sampled at the same age, are of little comparative value because of differences in body weight. Furthermore, rankings made at one age will differ from rankings at another age because of differences in growth rate. Follicle number, a figure proportional to the theoretical total number of follicles, permits valid comparisons. Male calves had higher follicle number than female calves. Africander crossbreds were no different from Herefords and Shorthorns, but Brahman crossbreds were 20% higher in follicle number. Individual animals of the same breed and sex differed significantly in follicle number, for which heritability was estimated at 29%. Between animals, follicle number was positively correlated with body weight. The significance and possible utility of follicle number as an indication of a component of body size is discussed.
A continuous nutrient flow technique for comparative studies in plant nutrition
Authors: Andrew CS , Pieters WHJ
Published: November 2004

A continuous nutrient flow technique for comparative studies of plant nutrient uptake is described. In this technique the nutrient solution enters a common mixing bowl before passing to the separate containers that are used for each batch or species of plants. The solution is continuously transferred through the individual containers by compressed air or pump at rates approximating 24 l./hr/container, and the nutrient concentration can be maintained within 5-10% of requirement by the introduction of fresh solution via the mixing bowl. The apparatus ensures uniformity of nutrient concentration and is equally adaptable to low and high concentrations.
The interrelationship of solar radiation and leaf area index in determining the rate of dry matter production of swards of subterranean clover (Trifolium subterraneum L.)
Authors: Black JN
Published: November 2004

The relationship of crop growth rate, leaf area index, and solar radiation has been examined for swards of subterranean clover, of the variety Bacchus Marsh. Leaf area index was varied by growing swards at eight densities of sowing, and radiation varied by two levels of shading, in addition to full daylight; the whole experiment was done three times—in summer, early winter, and spring—at the Waite Agricultural Research Institute, Adelaide. Crop growth rate was measured as the difference between the dry weights of the swards on two harvest occasions, and was calculated from smoothed values obtained by fitting an appropriate equation to the yield : density relationship. Thus a set of nine curves were available, each showing the response of growth rate to varying leaf area index at a specific level of radiation. These nine curves formed a consistent series, the growth rate rising with leaf area index until a maximal value was reached at the "optimum leaf area index", thereafter falling. At low levels of radiation, growth rate fell to zero at high leaf area indices. Both the maximal growth rate and the optimum leaf area index increased with radiation, and an analysis of the data indicated that these growth indices were dependent on radiation, the effect of temperature being negligible. A generalized series of curves was calculated by extrapolation, so that crop growth rates can be derived for any combination of leaf area index and radiation. A comparison of maximal crop growth rates and percentage utilization of light energy of subterranean clover and other crops suggests that this clover is relatively inefficient in integrating its environment.
The cobalt requirement of subterranean clover in the field
Authors: Ozanne PG , Greenwood EAN , Shaw TC
Published: November 2004

Yield increases of 30% were obtained on two subterranean clover pastures in response to dressings of 2 and 10 oz CoSO4.7H2O per acre. A dressing of salts containing chromium, nickel, vanadium, tungsten, aluminium, and iodine had no effect. Applications of cobalt increased the nitrogen content of the clover in all cases. No response to cobalt was obtained in the presence of adequate applied nitrogen. Clover growth was sharply reduced when cobalt contents fell below 0.04 p.p.m. The unfertilized soils on which the experiments were located contained only 0.022 and 0.019 p.p.m. cobalt in the 0–4 in. layer. Applied cobalt was not leached downward but remained in the surface 4 in. However, less than 0.5% of the applied cobalt was taken up by the pasture. To obtain a response to applied cobalt it appears necessary for legumes to be growing in soil containing Rhizobia capable of symbiotic nitrogen fixation; but the soil must also be very low in available cobalt and nitrogen.
Factors affecting the occurrence of mottling in wheat
Authors: Lipsett J
Published: November 2004

Several varieties of wheat were grown in pot culture with different levels of applied phosphorus, sulphur, nitrogen, and water. These treatments affected the incidence of mottling in all varieties, irrespective of their ordinary grain type. High amounts of nitrogen relative to other nutrients, and restriction of watering after flowering, increased the proportion of vitreous (non-mottled) grains. Vitreous grains generally had a higher nitrogen percentage than mottled grains. The total nitrogen content (N per 1000 grains) of vitreous grains in the nutritional trials was high, but that of vitreous grains in the watering experiment was lower. These latter grains had a high nitrogen percentage by virtue of reduced size. It is likely that vitreous grains due to both effects may be found in commercial samples.
Relationship between suint and the sweat glands
Authors: Stacy BD , Brook AH , Short BF
Published: November 2004

In the fleece of sheep with different types of skin, suint (cold water extract of the greasy fleece) was shown to be associated with the presence and size of the sweat glands. In the absence of sweat glands, suint was produced in substantially less than normal quantities, whereas the amount was much greater where the sweat glands were large.Similarly, the amount of potassium in suint, in skin, and in fluid from dermal cysts was much larger in the presence of sweat glands. The conclusion that suint is therefore largely produced by sweat glands was substantiated by the detection of high concentrations of potassium in sheep sweat.
The release and survival of Dermatophilus dermatonomus zoospores
Authors: Roberts DS
Published: November 2004

Observations were made on the release of Dermatophilus dermatonomus zoospores from mycotic dermatitis scabs, and on the duration of their survival in the scabs. Soil samples from properties with affected sheep were tested for their ability to transmit mycotic dermatitis and for their capacity to permit the survival of zoospores and the growth of D. dermatonomus. The zoospores can only emerge from the scab when it is wetted and before they have lost through age their capacity for motility. After an initial delay, the zoospores are released rapidly during several hours. The infection must remain active or the scabs must remain dry to enable the zoospores to persist in lesions. These observations support the view that a high transmission rate would be more likely when there were already some actively infected sheep in the flock. The dependence of the release of zoospores on wetting, and the effects of heat on survival and on bacterial competition, suggest that transmission would be favoured by cool wet weather. None of the soils collected was infective for the skin of susceptible sheep, and none of those tested was able when unsterilized to support growth, survival, or continued infectivity in the wet state. Of eight soils contaminated with scab material and kept dry, however, six were still infective after 4 months (the longest period tested). It is concluded that although contaminated soil may cause some infections, the survival of the species D. dermatonomus and the initiation of mycotic dermatitis outbreaks are more likely to depend on the existence of active infections.
Corrigendum - Accumulation of nitrate in oats infected with barley yellow dwarf virus
Authors: Stubbs LL , Walbran WI
Published: November 2004

A comparison was made of the nitrate levels of healthy Algerian oats and those infected with barley yellow dwarf virus (BYDV), the plants being grown on three soil types in containers in an insect-screened glass-house, under conditions of low nitrogen nutrition. The nitrate level of virus-infected plants was significantly higher than that of healthy plants, and within the range considered to be toxic to ruminants. In plants grown in a peat-sand mix with abundant applied nitrogen, infected oats were not markedly dwarfed; their foliage dry weight was not significantly less than that of healthy oats, but nitrate accumulation was significantly less. The possible significance of the association between nitrate accumulation and BYDV infection in oats is discussed in relation to nitrate poisoning of livestock.
A technique for the estimation of energy expenditure in sheep
Authors: Young BA , Webster MED
Published: November 2004

An endotracheal flow divider is described which permits sheep to inhale via the nasopharynx and exhale through an expiratory valve at the level of the trachea. The technique is applied to the measurement of oxygen consumption in feeding sheep, and results are reported which show that preservation of air flow through the nasopharynx eliminates the disturbances to respiratory pattern and feed intake associated with intubation techniques which by-pass this region.
The relationship between the rate of heat production and the level of milk production in a subtropical climate
Authors: Berman A , Amir S , Volcani R
Published: November 2004

Heat production as determined by the open circuit mask method, thermoregulatory responses, fat-corrected milk (F.C.M.) yield, and feed intake were recorded in two groups of 11 Israeli-Holstein cows each from the seventh day after calving up to 104 days of lactation. One group was fed according to the Fredricksen standard and the other group ad libitum, its feed intake being 125% of the Fredricksen standard. The experiment was carried out from January to mid July. No apparent heat increment of lactation was observed in the group fed according to the Fredricksen standard. A highly significant heat increment was found (10.3 kcal/hr/kg F.C.M.) at lower air temperatures (16–22°C) in the group fed ad libitum, while at higher air temperatures (23–28°C) a smaller, non-significant heat increment (5.4 kcal/hr/kg F.C.M.) was found. The hourly rate of heat production, the rectal temperature, respiration rate, respiratory volume, and respiratory vaporization changed only by small non-significant amounts with increasing temperatures. From these data it is inferred that heat production did not increase above heat requirements, except for the group fed ad libitum during the period at lower temperatures. This is explained by an increase in the critical temperature of the animals through a gradual adaptation to the summer conditions. This adaptation involves a decreased peripheral insulation by the summer coat and a lower basal metabolic rate. It is , suggested that these adaptational processes occurring in nature should be considered in studies on heat increments of feeding and of lactation.
Energetic efficiency of fattening sheep. I. Utilization of low-fibre and high-fibre food mixtures
Authors: McCGraham N
Published: November 2004

The energy, carbon, and nitrogen exchanges of nine castrate male sheep in moderately fat condition were determined with the aid of closed-circuit indirect calorimetry. Five of the sheep were kept on a diet containing equal parts of chopped lucerne hay and chopped wheaten hay (mixture A). The other four were given a pelleted 5:4:1 mixture of lucerne hay, maize meal, and peanut meal (mixture B). Each mixture was given at five different rates and each sheep was fasted on two occasions. Digestible energy averaged 62% for mixture A and 76% for mixture B, irrespective of feeding level. Of this, 10% was lost as methane and 5 to 13%, depending on level of feeding, in the urine, leaving on the average 81% metabolizable. Thus metabolizable energy amounted to 51 and 62% of the gross energy intake with mixtures A and B respectively, while net energy was 89 and 97% of the metabolizable energy intake at the lowest level of feeding and 61 and 69% at the highest. At any given level of metabolizable energy, mixture B provided 30% more digestible nitrogen than mixture A, but, allowing for differences between sheep in nitrogen economy, any additional energy obtained from mixture B was stored in fat. Consideration of the present results, along with data from earlier experiments with fattening sheep and cattle, showed that the net availability of metabolizable energy, both for maintenance and fattening, decreases regularly as the quantity of digestible fibre increases. Net energy could be estimated more accurately from this relation than by use of the commonly used factors of Kellner.
Digestion of food by the grazing sheep. I. The rate of flow in digesta
Authors: Hogan JP
Published: November 2004

Studies have been made of the rates of flow of digesta from the reticulum and the abomasum in sheep. It has been established that the rates of flow may be estimated by reference to the "marker", radioactive chromium ( 51Cr) complexed with ethylenediaminetetra-acetic acid. The use of lignin to measure the flow of digesta in grazing sheep has also been investigated.
The effect of trichostrongylosis on pasture intake of sheep
Authors: Holder JM
Published: November 2004

The pasture intake of previously worm-free Merino sheep after infestation with the intestinal parasite, Trichostrongylus colubriformis, was compared with that of similar but non-infested sheep. The infestation did not produce a fall in food intake, an effect in direct contrast to that usually reported for pen-fed sheep. Body weights of infested sheep were not affected. The effect of the presence of intestinal parasites on the accuracy of the indirect "ratio" methods for estimating pasture intake of individual animals is discussed.
Proteolytic enzymes produced in liquid media by Fusiformis nodosus
Authors: Thomas JH
Published: November 2004

Four strains of Fusiformis nodosus examined were shown to produce proteolytic enzymes digesting azocasein. When enzyme activity was plotted against the age of culture, the curves obtained showed two maxima, the first coinciding with the end of the logarithmic phase of growth, and the second with the end of the stationary phase. Enzyme preparations obtained at either of these stages of growth had similar properties, and digested casein and haemoglobin. The addition of sulphydryl compounds was without effect on the casein-digestive activity of either preparation, but enhanced the digestion of haemoglobin. The optimum pH for casein digestion by either preparation was about 9.5. Both preparations had similar stability to treatment by acid or alkali and both were inactivated by exposure to temperatures greater than 50°C.
Diffusion pressure deficit and turgidity relationships of detached leaves of Trifolium repens L.
Authors: Shepherd W
Published: November 2004

Diffusion pressure deficits (D.P.D.), relative turgidities, and recoverable turgid moisture contents were determined during drying out of laminae and petioles of detached leaves of white clover (Trifolium repens L.). Relationships varied with the type of wilting treatment. Slow, prolonged wilting, such as occurs during field drying for hay, resulted in higher D.P.D.3 and turgid moisture contents, in the later stages of drying, than rapid, brief wilting. The higher deficits account, in part, for the slowness of drying in the later stages of field drying of the species. The changes of deficit and hygroscopicity were not directly related. Possible causes of each are considered.
Pasture spelling as a control measure for cattle ticks in southern Queensland
Authors: Wilkinson PR
Published: November 2004

When two herds of cattle (A and B) grazed their paddocks continuously, tick infestations of the herds were similar. In the second phase of the experiment, lasting 18 months, when herd B grazed two halves of its paddock alternately, tick infestation of this herd was about one-fortieth of that on herd A, which grazed an undivided paddock throughout; during this period herd A was sprayed with DDT on four occasions to control excessive tick infestations, whereas herd B did not require spraying. The lightness of infestation of herd B was attributed to the first move of this herd taking place in May when engorged ticks would produce few or no progeny, and to subsequent moves at about 4-monthly intervals which prevented the tick population from rising to troublesome levels. In the third phase of the experiment the subdivision fence was removed from herd B's paddock, and herd A's paddock was divided into two, so that in this phase 'pasture spelling' and "continuous grazing" treatments were interchanged. There was then an intermittent decline in tick counts on herd A and an increase on herd B, over the following 2 years. During this phase, tick counts on herd A totalled about one-third of those on herd B. Throughout the experiment the rate of increase of ticks did not exceed five times per generation. During phase 2, herd B gained more weight than herd A. This lead was maintained during phase 3. After the cattle left the paddocks in January 1957 and 1958, randomized pasture sampling showed a rise in larval numbers, followed by a decline to negligible levels after 2-3 months. In winter, larvae persisted for longer and less predictable periods. Engorged ticks were placed out in a wide range of environments for observations on egg production, egg development periods, percentage hatch, and duration of larval survival. Results were similar to earlier published data, based on observations in a small enclosure at Brisbane. Larvae which had survived up to 13 weeks on grass succeeded in maturing to adults when placed on cattle.
Wether bioassay of annual pasture legumes. III. The oestrogenic potency of dry subterranean clover pastures, and of leaf blade and petiole in the green state
Authors: Francis CM , Millington AJ
Published: November 2004

Late summer pastures of nine strains of subterranean clover had very low oestrogenic activity as assessed by wether teat length bioassay. Only the Dwalganup variety had measurable activity which may have been due mainly to moderate levels of coumestrol in the various dry plant fractions. The activity of green leaf blade of the Yarloop strain was about nine times as great as that of the petioles. Possible agronomic implications of this finding are discussed.
Reproductive performance of Merino ewes grazing red clover (Trifolium pratense L.), improved pasture, or native pasture
Authors: Barrett JF , George JM , Lamond DR
Published: November 2004

Each year, commencing in 1957, fine-wool Merino ewes that were born in 1954 grazed native and improved pasture from the time of weaning of their lambs (usually late January) until the end of the period when they were joined with rams (early June). For the remainder of each year, one group each grazed (A) improved pasture, (B) native pasture, and (C) a red clover (Trifolium pratense) pasture. Records of services, lambings, and birth and weaning weights of lambs were obtained each year until the final weaning in January 1963. Lambing, as a percentage of ewes joined, declined between 1957 and 1962 from 85–88% to 66% in groups A and B and to 25% in group C. An average of 89% of ewes that lambed each year conceived to the first service. This was not influenced by years or treatments. The total number of services recorded per group was greatest for group C. Birth weights were lighter and weaning weights were heavier for the lambs of group C when compared with those of groups A and B. Ewes that failed to lamb in any year tended to fail in successive years; hence the increases in flock infertility were due to ewes becoming sterile. A number of sterile ewes had cystic glandular hyperplasia of the endometrium.
Nurtitional evaluation of meat meals for poultry. III. Association of chick growth with the bone, calcium, and protein contributed by meat meals to diets, and the effect of mineral and vitamin plus antibiotic supplementation
Authors: Sathe BS , McClymont GL
Published: November 2004

Experiments were conducted to study the effect on chick growth of equalizing the bone, bone ash, or calcium contents of diets based on wheat plus skim milk and containing high or low quality meat meals with and without soybean meal, and of supplementing these diets with minerals and with vitamins plus antibiotic. Bone or ash content was the major cause of variation in the growth of chicks on diets in which meat meal provided about 35% and soybean meal about 22% of the total dietary protein, but not on diets in which meat meals provided about 57% of the protein. The first type of diet gave significantly faster growth than the second type, but this was not due to the lower bone or calcium content of the first type. The results are interpreted as indicating that when meat meals provided a major proportion of the protein, protein quality rather than the bone or ash content of the diets was the major cause of variation in growth. As supplementation with bone ash, or bone with the same ash content, or with calcium carbonate with the same calcium content, depressed growth equally, it was concluded that the main cause of depressed growth on diets containing high levels of added bone was the high calcium content of the diets. Though supplementation of some low quality meat meal diets with minerals, with or without vitamins plus antibiotic, slightly increased growth rates, the variation in growth-promoting ability between diets containing high and low quality meat meals was not appreciably reduced. The experiments confirmed previous indications that the growth-promoting ability of a meat meal included in chicken diets is mainly the resultant of any growth depression due to excess calcium and growth promotion due to the contribution of essential amino acids.
The utilization of roughage by sheep and the red kangaroo, Macropus rufus (Desmarest)
Authors: Foot JZ , Romberg B
Published: November 2004

Two roughage diets, lucerne hay and oat straw, were given to three Corriedale sheep and three red kangaroos. Dry matter intakes, nitrogen balances, and body weight changes of the animals were compared, and the digestibilities of each diet by each species and the retention times of the food residues in their alimentary tracts were estimated. The kangaroos were less affected by the quality of the diet than were the sheep. The sheep ate nearly the same amount of lucerne hay and less oat straw than the kangaroos, after adjustment for body weight differences. Digestibility coefficients were higher for the lucerne hay when fed to the sheep, but apparent dry matter digestibility coefficients for oat straw were about the same for sheep and kangaroos. The mean retention times of food residues were lower in the kangaroos, and dietary nitrogen was retained to the same or a slightly lesser extent than in the sheep. The kangaroos maintained weight on the poor quality diet and appeared to be even better adapted to utilize this type of roughage than the sheep.
Paths and mechanisms of moisture movements in detached leaves of white clover (Trifolium repens L.) II. Effects of lamina treatment losses of petiole moisture
Authors: Shepherd W
Published: November 2004

Drying rates of laminae and petioles of detached leaves of white clover (Trifolium repens L.) were measured after lamina treatments involving crushing, slitting, and drying in hot or humid air. Lamina transpiration of petiole moisture ceased at a lamina moisture content of approximately 1.5 g moisture per g dry matter (g/g). Delaying the drying of laminae to this level increased the rate of drying of petioles, but only to a petiole moisture content of approximately 4 g/g. Thereafter, lamina transpiration of petiole moisture, if it continued, was alternative to, but no more rapid than, transpiration direct from petiole surfaces. Implications concerning field drying of harvested clover are considered.
The influence of the chemical composition of the diet on liveweight change in sheep
Authors: Vercoe JE , Hall WB
Published: November 2004

An incomplete block design balanced for residual effects, with an extra period, was used to investigate the effect of seven diets, differing widely in their chemical composition, on the nutritional requirement for the maintenance of liveweight in individually penned sheep. The mean liveweight changes for all diets at the chosen level of feeding were negative although all but one of the diets produced mean positive nitrogen balances. Slightly more than 96% of the variation in liveweight change due to diets could be accounted for by the following regression: Y = a + bX1 + cX2 + dX3 + eX4
where Y is the liveweight change (g/day), X1 the dry matter intake (g/day), X2 the initial liveweight (kg), X3 the metabolizable energy plus methane intake (kcal/day), and X4 the nitrogen balance (g/day).
X1 alone accounted for approximately 75% of the variability.

The effect of X3, once X4 had been accounted for, was extremely small under these nutritional conditions. After covariance adjustments for dry matter intake and initial liveweight to the seven dietary means, a regression was fitted for adjusted liveweight change on nitrogen balance. This equation had the form:
YA = a + bX4+ cX4²
Nitrogen balance is closely related to nitrogen intake ( = dry matter intake x percentage nitrogen). At constant dry matter intake, the above equation can be written in terms of percentage crude protein (N x 6.25) in the diet. The possible reasons are discussed for the small effect of metabolizable energy intake on liveweight change once the dry matter intake is held constant.
Further studies on oestrogenic activity in strains of subterranean clover (Trifolium subterraneum L.) in South-western Australia
Authors: Davies HL , Dudzinski ML
Published: November 2004

The oestrogenic activity of several strains of subterranean clover was measured by the response in uterine weight in ovariectomized ewes. Large differences in oestrogenic activity between strains were found and a tentative ranking of strains is given. There were between-site and between-year differences in activity within any one variety. Oestrogenic activity was maintained when the green clover was dried rapidly in a forced-draught dehydrator. When the same clover was made into hay, there was sometimes a diminution in oestrogenic activity. There was no oestrogenic activity in clover that had set seed and matured in the field. Cobalt either in the rumen or applied as a fertilizer to the pasture did not affect oestrogenic activity.
The performance of hybrids between Mediterranean and Northern European parents of cocksfoot (Dactylis glomerataL.) in a mediterranean type environment
Authors: Knight R
Published: November 2004

Hybrids were produced between seven different parents of Mediterranean origin and two parents of Northern European origin. A special technique of controlled flowering, emasculation, and pollination was used to effect the hybridization. Hybrid plants were grown in undefoliated swards and assessed for cumulative growth, variation in the reproductive phase, tillering, and summer survival. The combining abilities of the parents were estimated for these characters. Hybrids between Mediterranean and Northern European parents were able to respond to summer showers at a time when Mediterranean material was still summer dormant and Northern European material severely affected by dry summer conditions. This out-of-season growth was reflected in the higher yields of the hybrids in the autumn after the main start to the growing season. During midwinter when the Mediterranean material was growing actively the growth of Northern European material ceased and some combinations of Mediterranean and Northern European parents ceased growing. The cessation of growth was attributed to winter dormancy. Plant survival during the summer was 97% for the purely Mediterranean families, 88% for Mediterranean x Northern European families, and 59% for the purely Northern European families. Some of the Mediterranean x Northern European families survived as well as the best Mediterranean families. The potential agricultural value of the Mediterranean x Northern European hybrids and a possible breeding programme with them are discussed.
Susceptibility, inhibition of infection in stolons, and induced resistance to rugose leaf curl virus infection in white clovers
Authors: Grylls NE , Day AW
Published: November 2004

Rugose leaf curl virus (RLCV) disease is more widespread in legumes of agricultural importance than was previously recorded. The presence of the virus was confirmed in stoloniferous white clovers (Trifolium repens L.), red clover (T. pratense L.), lucerne (Medicago sativa L.), and peanut (Arachis hypogea L.) from Queensland, and T. repens and T. pratense from New South Wales. In greenhouse experiments, differences in susceptibility to infection were demonstrated between nine varieties and strains of T. repens and T. pratense. The varieties Lodi and Ladino were significantly more resistant than others tested. A number of stolons that developed from severely infected plants in the greenhouse were apparently free of virus. Attempts to transmit virus from clones established from these plants, by means of the insect vector and by grafting, failed. Clonal plants derived from symptomless stolons of infected plants were observed to be more resistant to infection with RLCV than were clones taken from previously uninoculated seedlings. In further experiments, infection of plants derived from apparently virus-free stolons arising out of severely infected plants was significantly lower than that of similar plants taken from previously uninoculated clonal plants of the same seedling material. The degree of resistance to infection varied between varieties and between seedling lines within varieties. The results suggest acquired or induced resistance to infection and provide an explanation for the apparent recovery from, and low incidence of, RLCV in susceptible white clovers in the field. The nature of the resistance is not known, but the evidence suggests a mechanism associated with necrosis of stolons. The effect of virus infection on pasture yield and the implications of the development of virus-free plants resistant to RLCV are briefly discussed.
Milk quality in Merino and Corriedale ewes
Authors: Moore RW
Published: November 2004

Comparisons have been made of the milk quality of ewes of two strains of Merino, strong-wool (S) and medium-wool Peppin (B), and of two breeds, strong-wool Merino and Corriedale (C). The strains were compared in two ways – for ewes suckling single lambs and for ewes suckling a pair of twins containing one lamb of each strain, and the breeds were compared for ewes suckling single lambs. The strain comparisons were made in 1960–61 and the breed comparison in 1961–62. Ewes of the S and B strains during the first 10 weeks of lactation had milk with mean fat percentages of 6.0 and 6.5 respectively when suckling singles, and 6.4 and 7.2 when suckling twins. The corresponding percentages for solids-not-fat (S.N.F.) for the period 45–72 days after parturition were 9.5 and 9.3 for singles, 9.9 and 10.2 for twins. The C breed and the S strain yielded milk with respective mean fat percentages of 8.6 and 9.4, and mean S.N.F. of 10.1 and 10.6, during the first 20 days of lactation. The only statistically significant difference among these breed and strain comparisons was the breed difference in S.N.F. In Merino ewes suckling twins the fat percentage was higher than in those suckling singles over 10 weeks of lactation (6.8 v. 6.2), while the percentage of S.N.F. for the period 45–72 days after parturition was also higher (10.1 v. 9.4). The difference in fat was not significant, but the difference in S.N.F. was. When adjusted for the higher amount of whole milk produced by ewes suckling twins, the relative amounts of fat and S.N.F. secreted become 116 : 100 and 112 : 100. There is thus a suggestion that the extra sucking stimulus which leads to a greater production of whole milk also increases the secretion of fat and S.N.F. When the 10-week lactation period was divided into three subperiods, the fat percentages showed a significant increase with time since parturition for Merino ewes suckling singles (5.7 : 5.8 : 7.2) or twins (5.7 : 6.8 : 7.9). Even when these figures were adjusted for amount of whole milk, the relative total amounts of fat secreted were 100 : 105 : 102 and 100 : 111 : 104. Lamb growth rate was no more highly correlated with the constituents of milk quality than with the total amount of whole milk. No important differences in milk quality were found between the genetic groups examined, but these were all related, the Corriedale breed being half Merino. The possibility remains that breeds differing more widely in their genetic background might also differ in milk quality.
Studies on the diet of the grazing animal. I. Seasonal changes in the diet of sheep grazing on pastures of different availability and composition
Authors: Arnold GW , Ball J , McManus WR , Bush IG
Published: November 2004

The diet of grazing sheep was studied by using animals with oesophageal fistulas. Seasonal changes in the botanical and chemical composition of the diet when grazing Phalaris–annual grasses–subterranean clover pasture are described. The effect of grazing intensity on diet is considered. A comparison was made of diets on seven pasture species. None of the species examined had a useful qualitative superiority over Phalaris either in winter or in summer, when the digestibility of this species declines considerably. Relations between botanical and chemical composition of the diet and the pasture are discussed. Significant relations were established between the nitrogen and soluble carbohydrate contents of diets and their digestibility.
Status of introduced parasites of Queensland fruit fly Dacus (Strumeta) Tryoni. 1962–1965
Authors: Snowball GJ
Published: November 2004

The paper records results and conclusions from field samplings made in eastern Australia during March 1962–March 1965 to assess the influence of opiine parasites introduced from Hawaii in 1958–1959 for controlling the Queensland fruit fly (Strumeta tryoni). Of the introductions, Opius oophilus alone is established on the mainland, where it appeared to use seven dacine and trypetine species as hosts. Its ability to disperse and the frequency of its recovery were enhanced towards the northern end of its distribution. O. oophilus continued to show marked preferences for parasitic activity in certain fruit types such as Averrhoa carambola. Levels of parasitism fluctuated widely between localities and sampling occasions. O. longicaudatus occurred alone at Lord Howe Island, where it was active at some 16-38% of sampling sites providing infested fruits. Levels of parasitism of the two established host flies were low and no marked fruit preferences were shown. Indications are that neither imported parasite is materially affecting the incidence either of its hosts or of native parasites.
The effect of red clover pasture on the reproductive tract of ram lambs
Authors: George JM , Turnbull KE
Published: November 2004

Fine-wool Merino ram lambs, weaned at c. 3 months of age, were grazed on either red clover (Trifolium pratense L.) or grass-dominant pastures. Red clover did not retard puberty, and at c. 6 months of age the lambs showed no significant effect of clover on liveweight, weight of testes, and epididymides or the number of epididymal sperm. At 12 months of age the body weight, weight of testes, and epididymides and epididymal sperm numbers were all significantly greater on the red clover pasture. A bioassay made when the animals were 9 months old indicated that the effective intake of oestrogenic substances obtained from grazing red clover was greater than the equivalent of 15 µg stilboestrol dipropionate per day given intramuscularly.
A relationship between seedling growth rates and latitude of origin of cocksfoot populations
Authors: BrouT P , Kawanabe S
Published: November 2004

Growth rates of vegetative seedling plants of 15 cocksfoot (Dactylis glomerata L.) populations were measured in long days at near optimum temperature. Relative growth rate of the plant tops was greater in populations from high than in those from low latitudes of origin (r = 0.85; P < 0.001). In a second experiment, the populations from low latitudes were found to initiate inflorescences earlier than those from high latitudes. It is suggested that environmental conditions which maximize population differences in time of floral initiation also maximize differences in growth rates during the vegetative phase of growth.
The net energy value of three subtropical forages
Authors: McCGraham N
Published: November 2004

Energy and nitrogen balance experiments with three subtropical forages, a legume and two grasses, are reported. Each forage was given to four sheep at several levels of feeding. One of the forages had a low nitrogen content (4% crude protein) and was supplemented with urea and molasses containing 7 g nitrogen and 56 kcal/day. This caused voluntary consumption to increase by 50% and digestibility of all chemical constituents to increase by 6–12 units. Utilization of metabolizable energy for maintenance also improved by approximately 10%. Digestible energy (42–62%) was predicted quite accurately from chemical composition by means of published equations which refer to forages grown in temperate climates. Metabolizable energy was close to 82% of digestible energy, as found with non-tropical forages. Net availability of metabolizable energy for maintenance ranged from a very low 60% to 80%. It was predicted more accurately from percentage metabolizable energy than from digestible crude fibre: the reverse applied to net availability for production (40–50%).
Bioassay responses of ewes to legume swards. I. Uterine weight response: Variability, calibration, and prediction
Authors: Bennett D , Dudzinski ML
Published: November 2004

Statistical analyses of sheep uterine weight responses to synthetic oestrogens and oestrogenic pastures showed that wet uterine weights were relatively less variable than dry weights. Body weight and uterine score at ovariectomy could be used as independent variables to reduce the variance of wet uterine weights. The best combination of scales to reduce variability in uterine weight was log (uterine weight) (Y axis) and log (body weight) or log (score) as covariates (X axis). For calibration of stilboestrol response log (uterine weight) regressed on log (dose (µg) + l) gave the most satisfactory result. This transformation gave common slopes for all sheep and assays but did not eliminate vertical displacement between assay calibration lines. Responses of virgin Merino and virgin crossbred ewes were similar. The paper discusses the precision of comparisons within and between assays and the limitations to improvements in precision. It also sets out guides as to the allocation of sheep in future assays to obtain maximum information per sheep.
Studies on resistance in calves to experimental infection with the nodular worm, Oesophagostomum radiatum (Rudolphi, 1803). III. The stimulation of resistance by multiple infections with larval stages
Authors: Keith RK
Published: November 2004

Observations are reported on the influence of multiple infections with larval stages of Oesophagostomum radiatum on the stimulation of resistance in calves to reinfection with this parasite. Calves were given spaced doses of infective larvae, and the resulting infections were terminated in the early fourth stage by treatment with an anthelmintic. The egg counts, numbers of adult worms recovered at necropsy, and the pathological changes observed in the intestine subsequent to a test dose indicated that the reinfected calves had developed a high degree of resistance. The reinfected calves made significantly lower weight gains than uninfected control calves during the period of exposure to the larval infections. The results suggest that the immunogenic products of adult worms, and of third stage or early fourth stage larvae, are qualitatively similar.
Water metabolism of Merino and Border Leicester sheep grazing saltbush
Authors: Macfarlane WV , Howard B , Siebert BD
Published: November 2004

During late summer, Border Leicester wethers running with Merinos on a pure Atriplex nummularia stand turned over 10.6 to 17.5 litres (mean 13.7 litres) of water daily, and diluted the sodium and potassium ingested to less than 1000 m-osmoles/litre in the urine. Leicesters used 46% more water than Merinos as litres/24 hr, and 71% more as ml/kg0.82/24 hr. The two breeds produced similar urine concentrations. The sheep showed a wide variation in response, and their individual water turnovers while feeding on Atriplex vesicaria and A. nummularia ranged from 120 to 833 ml/kg0.82/24 hr. This suggests differences in functional types of adjustment to saltbush associations. On a Danthonia community Leicesters again turned over more water than Merinos but only about half as much water was required as on saltbush. Merinos grazing on A. vesicaria (with some grasses available) over 2 years maintained good condition with half the water intake of Merinos on A. nummularia, although the two species of saltbush had similar sodium and potassium contents. Total body water tended to increase with water turnover rate on saltbush. Plasma sodium concentration was inversely related to water turnover, extracellular volume, and total body water on saltbush pastures. The content of extracellular sodium was, however, greatest in the sheep with the least sodium in the food taken.
Isotopic studies on the uptake of nitrogen by pasture plants. IV. Uptake of nitrogen from labelled plant material by Rhodes grass and Siratro
Authors: Henzell EF , Martin AE , Ross PJ , Haydock KP
Published: November 2004

Rhodes grass (Chloris gayana Kunth.) and Siratro (Phaseolus atropurpureus D.C. var. Siratro) plants were grown separately and together in pots of soil containing 15N-labelled ground Rhodes grass plant material (carbon/nitrogen ratio 44). The added plant material immobilized nitrogen during the first 6 weeks of the experiment, and nitrogen uptake by Rhodes grass was still less than that of the control at 15 weeks. Both the grass and the nodulated legume took up 15N throughout the experiment, despite the reduction in availability of unlabelled soil nitrogen. Siratro grown alone took up as much 15N as Rhodes grass grown alone. When the plants were grown together about one-third of the 15N uptake went into the Siratro and two-thirds into the Rhodes grass. The Siratro roots had a higher 15N enrichment than the tops, indicating that relatively more of the unlabelled nitrogen fixed from the atmosphere went into the Siratro tops, compared with the labelled nitrogen taken up from the soil. With Rhodes grass the tops had a higher enrichment than the roots. The difference between the extractable mineral nitrogen in the pots of soil under grass and in the bare pots accounted for uptake by the grass at 3 weeks but underestimated it at 15 weeks. In addition, there was a significant difference in enrichment between the total extractable mineral nitrogen in the soil and the nitrogen taken up by the Rhodes grass. From the uptake and partition of 15N it was calculated that 43–50% of the nitrogen in the Siratro plants at 3 weeks was taken up from the soil (the rest was attributed to symbiotic fixation); at 15 weeks only 2–4% of the nitrogen in the Siratro was from the soil. Very little nitrogen was transferred from the Siratro to the associated Rhodes grass.