bluuebunny/crossref_metadata_2025 huggingface dataset:
The utilization of parasites of oriental fruit fly (Dacus dorsalis) against Queensland fruit fly (Strumeta tryoni)
Authors: Snowball GJ , Wilson F , Campbell TG , Lukins RG
Published: November 2004

In 1950, a programme was initiated to utilize against the Queensland fruit fly (Strumeta tryoni) parasites which were introduced during 1948–1950 into Hawaii, where they produced a considerable reduction in the incidence of oriental fruit fly (Dacus dorsalis). The present paper describes the work carried out under this programme up to October 1959. During 1951–1957 the emphasis was on rearing, at Sydney, on Queensland fruit fly, stocks of Opius longicaudatus and O. oophilus from small stocks imported from Hawaii. It was found that O. oophilus, O. vandenboschi, and O. longicaudatus could parasitize Queensland fruit fly in the laboratory, and that O. longicaudatus could parasitize the Solanum fruit fly, Strumeta cacuminata, which occurs widely in the distribution area of the Queensland fruit fly and hence might act as a valuable alternative host for the parasites. Liberations were made at Coffs Harbour and Sydney in New South Wales in 1956–1957 of 21 000 O. longicaudatus and 1 700 O. oophilus, but establishment was apparently not achieved. The programme was changed in 1957 to provide for larger releases over n much wider area. In view of production difficulties at Sydney, a field station was set up in Hawaii to rear parasites, which were shipped to Australia by air, checked in quarantine at Sydney, and despatched to various parts of Australia for liberation. Between March 1958 and October 1959 the following numbers of foreign parasites were liberated: O. oophilus, 229 200; O. vandenboschi, 28 100; O. longicaudatus and closely related species, 198 700; O. incisi, 27 100; Dirhinus giffardii, 2 500; Tetrastichus giffardianus, 2 500; and Syntomosphyrum indicum, 3 200. The liberations in 1958–1959 were made at 25 locations in New South Wales, 59 in Queensland, 12 in Western Australia, and 6 on Lord Howe Island. The liberations were made in the presence of populations of Queensland fruit fly in New South Wales, Queensland, and on Lord Howe Island, and of Mediterranean fruit fly (Ceratitis capitata) in Western Australia. Data from a total of 185 fruit samples taken between January and August 1959 in New South Wales and Queensland indicate that O. oophilus was possibly established in five localities in New South Wales and two in Queensland, and that some field breeding had occurred of O. vandenboschi and O. longicaudatus in New South Wales. There were no recoveries indicating field breeding of the three species in central or north Queensland. The indications of establishment of O. oophilus are tentative because the relevant samples were taken before the parasite populations had been subjected to winter conditions. There were no recoveries of O. incisi, S. indicum, or T. giffardianus.
Light relationships in grass-clover swards
Authors: Stern WR , Donald CM
Published: November 2004

Grass-clover swards were grown at four levels of nitrogen to provide a range from extreme clover dominance to extreme grass dominance. Yield, botanical composition, leaf area index, and light density were measured at 3.5 cm vertical intervals in each of the mixed swards throughout the growth period. It was directly demonstrated that the growth of clover in these mixed swards was governed by a series of relationships, namely: (a) Increasing rates of nitrogen application gave increased yields of grass (positive). (b) Increased yields of grass gave higher leaf areas of grass disposed above the clover leaf canopy (positive). (c) Higher leaf areas of grass above the clover reduced the light density at the clover leaf canopy (negative). (d) Reduced light density at the clover leaf canopy caused a reduced growth of the clover (positive). Under conditions of heavy grass growth and of consequent low light density at the clover canopy, the growth of clover not only became slow but eventually was strongly negative, leading to a marked reduction in both the number of clover plants and the yield of clover.
Studies on seed pelleting as an aid to legume seed inoculation. I. Coating materials, adhesives, and methods of inoculation
Authors: Brockwell J
Published: November 2004

The influence of seed-pelleting techniques on the inoculation and nodulation of subterranean clover (Trifolium subterraneum L.) was studied in the laboratory and in the field on podzolic soil where clover nodulation following conventional seed inoculation practices was often unsatisfactory. Seed pellets were prepared with the use of 10 different coating materials, three adhesives, and two methods of inoculation. These were sown immediately after preparation or stored for short periods before sowing, and were examined in terms of inoculant survival, nodulation, and plant growth. It was shown that subterranean clover seed pelleted with a lime, blood plus dolomite, or lime plus blood plus dolomite coating attached to the seed with a 45% solution of gum arabic and inoculated by incorporating a commercial peat inoculant within the pellet can be stored for up to 4 weeks before sowing and the viability of the inoculant retained. This is reflected in improved nodulation and in growth of the seedling subsequently produced. Ecological considerations in respect of the establishment of the inoculum in the soil are discussed.
History of outbreaks of the Australian plague locust, Chortoicetes terminifera (WALK.) between 1933 and 1959, and analysis of the influence of rainfall on these outbreaks
Authors: Casimir M
Published: November 2004

An account of the history of outbreaks of the Australian plague locust, Chortoicetes terminifera, is presented for the period 1933–1959 from published information and records maintained by the New South Wales Department of Agriculture. Population fluctuations during this period have been examined in relation to rainfall for seven of the major and intermediate outbreak areas in New South Wales. It has been shown that rainfall during the months August to December is important in its influence on locust numbers the following season, whereas that occurring between January and April is apparently not. Subnormal "early season" rainfall favours an increase in the locust population of an area in the next season, while above-normal rainfall favours a locust decrease in the following season. In each of the outbreak areas selected there was a significant negative correlation between the current first locust generation of the season (measured in terms of an arbitrary scale or index) and preceding early season rainfall; and the estimated regression lines due to the two variables in each area were apparently parallel, although not coincident. A multiple regression analysis was carried out incorporating the preceding autumn locust generation as an extra independent variable. When the Culgoa-Barwon outbreak area was eliminated from the analysis, it was found that the regression equations for each of the six other areas could be considered identical, even to the constant term, any differences between areas being attributable to differences in the values of the independent variables. A single multiple regression equation based on the data for the six areas combined was calculated, and it is suggested that this can be used to forecast approximately the size of the spring locust generation in time to plan appropriate control measures. Difficulties inherent in the data are pointed out and the disturbing influence of invasion of one area by migrating swarms from another discussed. It is believed that more refined methods of estimating locust numbers and greater knowledge of locust behaviour in relation to long-term rainfall influences would allow predictions of much greater accuracy to be made, based on the correlations established in the present paper. The relative significance of outbreak areas situated mainly in the Central Division of New South Wales and those in far western parts of New South Wales and Queensland is discussed. It is suggested that two of the most serious outbreaks on record were the result of long-range migratory flights from the latter areas. The importance of these areas as a source of outbreaks affecting South Australia, Victoria, and southern New South Wales is also emphasized, and a tentative explanation of the role of early season rainfall in these arid regions is given.
The effects of pregnancy of the passage of food through the digestive tract of sheep
Authors: McC Graham N , Williams AJ
Published: November 2004

The rate of passage of food residues through the digestive tract of pregnant and non-pregnant Merino ewes was measured at four levels of feeding. The passage of digesta became more rapid as the level of feeding was increased, or, the intake being constant, as pregnancy advanced. The mean retention time fell by 3 hr per 100 g increase of food intake, and by 1 to 1½ hr per 100 g increase of estimated weight of concepta at constant intake. The digesta increased by about 150 g dry matter (depending on level of feeding) per 100 g increase of daily food intake and fell by about 150 g per 1000 g increase of estimated weight of concepta. Two alternative explanations of the changes of rate of passage during pregnancy are discussed. While reduction of the quantity of digesta by the increasing bulk of the uterus would tend to curtail appetite, increase of the flow of digesta as a physiological side-effect of pregnancy would tend to enhance appetite. In either case, more rapid passage of digesta would depress the digestibility of some rations and so contribute to undernutrition in late pregnancy.
Selection of cattle for tick resistance, and the effect of herds of different susceptibility on Boophilus populations
Authors: Wilkinson PR
Published: November 2004

Weekly counts of Boophilus microplus (Canestrini) on 30 Australian Illawarra Shorthorn heifers enabled the cattle to be ranked in order of tick infestation, with highly significant correlations between counts of two observers and between counts of one observer on different occasions. In May 1960, when the heifers were 1½–2 years old, 12 were selected as relatively tick-resistant and 12 as relatively tick-susceptible. Each of these groups was divided at random into herds of six, and the four herds were then allotted randomly to separate paddocks, each onequarter of the area previously grazed. A herd was sprayed with 0.5% DDT emulsion when its average count of ticks (adult females over 5 mm in length) on one side of the animals exceeded 40. During the ensuing tick season, from October 5, 1960, to June 7, 1961, the sums of average weekly tick counts, and the numbers of sprayings (in parenthesis) were: susceptible herds 4853 (5) and 5962 (6): resistant herds 718 (0) and 1073 (1). Counts of tick larvae on defined body areas showed that, in the summer after segregation, resistant herds carried fewer larvae than the susceptible herds, apparently because fewer mature ticks fell from the resistant cattle in the preceding spring and winter. As a consequence of this, counts of adult ticks were comparatively lower after than before segregation. There was little or no 'spring rise' of tick infestation on the resistant herds. There was no significant correlation between tick resistance and coat score, sweat gland dimensions, or total skin thickness, but a correlation of -0.53 with follicle depth was significant at the 1% level. There was no evidence of adaptation of cattle ticks to the resistant animals, either in the field experiment or in observations on stalled cattle. The experiment draws attention to the appreciable proportion of tick-resistant animals within the Australian Illawarra Shorthorn breed, which has largely been overlooked in past discussions on tick-resistant breeds of cattle. It also suggests a technique for estimating the improvement in tick control that may be obtained by a given degree of selection within any breed, for any given environment.
Studies on the oestrogenic potency of subtrerranean clover (Trifolium subterraneum L.) in South-Western Australia
Authors: Davies HL , Bennett D
Published: November 2004

The oestrogenic activity of three varieties of subterranean clover (Trifolium subterraneum L.) — Dwalganup, Yarloop, and Mount Barker — was measured by means of the response in fresh weight of uterus + cervix in both ovariectomized virgin and ovariectomized cast-for-age ewes. The standard oestrogen used was diethylstilboestrol, administered intramuscularly. There was no difference between virgin and aged sheep in the slope of the dose-response curve. Thus aged sheep can be used for biological assay of oestrogens. The varieties Yarloop and Dwalganup were highly potent; Mount Barker produced only slight increases in uterine weight. The relevance of these varietal differences in oestrogenic potency is discussed in relation to the sheep infertility problem associated with oestrogenic pastures.
Carbon tetrachloride poisoning in sheep: Effect upon the serum E260 value and plasma volume
Authors: Gallagher CH
Published: November 2004

Serum E260 values were determined at intervals in sheep which were given 50 ml carbon tetrachloride (CCl4) by stomach tube into the rumen, and in untreated sheep. After administration of the drug, the mean E260 value fell initially, being minimal at 3 hr. At this time, the circulating plasma volume had increased by one-fifth, and it is considered that this dilution factor largely explained the fall. The group mean for non-fatal cases rose above the pre-administration level at 7 hr, then returned to it by 24 hr. However, in the one sheep that died from CCl4 poisoning, the serum E260 value remained very high until death at 46 hr. In view of the significant variations in serum E260 values between untreated sheep, and the significant random variations in serum E260 values between times of bleeding such sheep, it is concluded that the determination of serum E260 values at isolated times in individual sheep is of no value as a diagnostic criterion of CCl4 poisoning.
The breed structure and genetic analysis of the pedigree cattle breeds in Australia. III. The Hereford
Authors: Davey GP , Barker JSF
Published: November 2004

(i) The structure and genetic history of the pedigree Hereford breed in Australia are analysed by pedigree sampling methods. (ii) The pattern of the breed structure is generally similar to that found in other breeds, but it is extremely dynamic owing to the present rapid expansion of the breed. Changes are taking place in the herd composition of the major breeders' groups and there are many new herds yet to find their level in the structure. (iii) Considerable emphasis has been placed on the use of imported animals in the development of the breed. Of all herds registering in Volume 24 of the herd book, 31.6% used imported sires, and the percentage of genes in the breed in 1949 derived from animals imported since 1880 was 97.7, and from animals imported since 1930, 53.9%. (iv) The most important herd in 1949 made a genetic contribution to the breed of 33.1%, while the contributions of the four next most important herds were 17.4, 10.1, 7.4, and 6.1%. In the four-generation pedigrees from which these figures were derived, the contribution of imported animals was 56.1%. (v) The animal with the highest relationship to the breed was Free Town Director (Imp.), with direct relationships of 5.6 and 9.2% to the 1941 and 1949 samples respectively. Of the 16 sires and one dam whose direct relationships are 3.0% or more in any of the three sample years, 12 sires were imported. (vi) The total inbreeding in 1949 (base year 1880) was 2.6%. This comprised 0.2% current inbreeding, 1.6% long-term inbreeding, and 0.8% strain inbreeding. There was no evidence of subdivision of the breed into separate strains. (vii) The effective generation length has decreased since 1930 to about 5.5 years in the 1949–50 sample. Nearly 50% of the animals in this sample were sired by bulls 4 years old or younger, while about 33% were from dams 4 years old or younger. (viii) Bulls from major breeders' herds are used widely throughout the breed, while about 90% of sires and 45% of dams were bred in herds other than the one in which they were used. Therefore, it is unlikely that there is much genetic variation between herds.
Some skin characters in five breeds of European (Bos taurus) dairy cattle
Authors: Nay T , Hayman RH
Published: November 2004

Observations were made of a number of skin characters in five breeds of European (Bos taurus L.) dairy cattle. Skin samples were taken from the cattle in January and July. There were differences between breeds in sweat gland volume and length! diameter ratio, in skin and papillary layer thickness, in the ratio skin thickness/papillary layer thickness, and in the degree of shrinkage in transverse sections cut from the papillary layer. There were no differences between breeds in density of follicle population (and hence sweat glands) per unit area of skin. Sweat gland volume, skin thickness, and papillary layer thickness were larger in winter than in summer, but there were no such differences for sweat gland length/ diameter ratio, the ratio skin thickness/papillary layer thickness, and follicle population density. The only significant overall correlations between characters were those between sweat gland volume and sweat gland length/diameter ratio, and sweat gland volume and papillary layer depth.
Necrotic yellows: A newly recognized virus disease of lettuce
Authors: Stubbs LL , Grogan RG
Published: November 2004

A previously undescribed virus disease of lettuce, for which the name lettuce necrotic yellows is proposed, occurs in epiphytotic proportions in Victoria and, to a similar or lesser extent, in parts of Queensland, New South Wales, and South Australia. Infected plants are extremely chlorotic and have a flattened appearance. They exhibit varying degrees of flaccidity and necrosis, and the mortality rate may be high. Chronically affected survivors have small, slightly distorted, but otherwise normal heart leaves. The tomato spotted wilt virus, which causes an almost identical disease in lettuce, lacks the "recovery" phase. The virus was sap-transmissible from infected lettuce or sowthistle (Sonchus oleraceus L.) to several indicator species, but not to lettuce or sowthistle. Lettuce has been infected on a few occasions with inoculum from Nicotiana glutinosa L. There is no evidence that the virus is transmitted through lettuce or sowthistle seed. The virus was inactivated in N. glutinosa sap between 52 and 54°C, was relatively short-lived in vitro (1–8 hr), and its dilution end-point was close to 10-2. Symptoms are described on known experimental hosts, including N. glutinosa, petunia, and spinach, that are regarded as the best differential indicators. Several lettuce-infesting insects—thrips (Thrips tabaci Lind. and Frankliniella schultzei (Tryb.)), leafhoppers (Orosius argentatus Evans), and aphids (Myzus persicae (Sulz.) and Macrosiphum euphorbiae (Thos.))—failed to transmit the virus from infected lettuce or sowthistle. Transmission was achieved with the aphid Hyperomyzus lactucae (L.) bred on infected sowthistle, the only known source in Victoria of both the vector and the virus. The virus persisted through a moult of the vector, and thus the mode of transmission is of the circulative type. H. lactucae has not previously been recognized as a vector of a "circulative" virus. It is considered unlikely that lettuce necrotic yellows virus is indigenous to Australia, because sowthistle, the only known natural host of both the virus and the vector, is an introduced species.
The variability of potassium concentrations in erythrocytes in relation to anaemia in sheep
Authors: Evans JV
Published: November 2004

A marked rise in the mean concentration of potassium in the erythrocytes of anaemic ewes with a lamb at foot is reported. Marked rises in potassium concentrations in erythrocytes or lowered packed cell volumes were not found in unmated or barren ewes in the same flock. The rise in the potassium concentration in the erythrocytes is discussed. It is suggested that self-limiting anaemia episodes may be more common in sheep, at least on the New England Tableland of New South Wales, than is normally suspected.
The effect of feeding on evaporative heat loss and body temperature in Zebu and Jersey heifers
Authors: Allen TE , Pan YS , Hayman RH
Published: November 2004

Some physiological responses to moderate (70–80°F dry bulb and 60–70° wet bulb) ante-room and high (103° dry bulb and 83° wet bulb) hot room temperatures by two Jersey and two Zebu heifers under alternate conditions of normal feed intake and fasting are reported. At moderate temperatures both breeds exhibited a diurnal rhythm in feed and water consumption and in skin temperature, sweating rate, rectal temperature, and respiration rate. In the case of skin temperature, sweating rate, and respiration rate this diurnal rhythm disappeared in the hot room. In the hot room, water consumption increased for all animals. Feed intake was depressed in Jerseys but not in Zebus. In the ante-room, animals tended to have higher sweating rates and rectal temperatures when fed than when not fed. Fed animals did not have uniformly greater skin temperatures in the hot room, but sweating rates, rectal temperatures, and respiration rates were greater. Jerseys had greater sweating rates and lower rectal temperatures than Zebus at ante-room temperatures, but Zebus had greater sweating rates and lower rectal temperatures in the hot room. When fed, Jerseys failed to control their temperatures in the hot room, despite large increases in sweating and respiration rates and a reduction in appetite; whereas Zebus maintained their appetites, and slightly reduced rectal temperatures, by means of their greatly increased sweating rate and a slight increase in respiration rate. Differences between Jerseys and Zebus in sweat gland volume were of the order previously reported for these breeds, and differences in population density were in accordance with differences in body size. The Jersey having the smallest sweat glands also had the lowest number per unit area, and sweated less than its Jersey mate.
Body composition in vivo. I. The estimation of total body water with antipyrine and the relation of total body water to total body fat in rabbits
Authors: Panaretto BA
Published: November 2004

Total body water estimates made in eight rabbits by the antipyrine dilution technique ranged from 52.6 to 69.7% of fasted liveweight. These estimates agreed closely with subsequent measurements of total body water, made by dessicating samples of the minced bodies, which ranged from 50.6 to 68.7% of the fasted liveweight. The relationship between total body water and total body fat was determined in 47 fasted rabbits in which these body components ranged from 47.2 to 71.8 and 3.6 to 34.6 % of liveweight respectively. This relationship was y = 95.5 - 1 .30x, where x and y are the percentages of water and fat respectively in the live animal. The mean water content of the lean body mass was 72.6 � 1.1 % for the 47 rabbits in these experiments.
The effect of stilboestrol administered during an Autumn mating on reproduction in Merino sheep
Authors: Morley FHW , Bennett D , Axelsen A
Published: November 2004

Ewes were injected subcutaneously with stilboestrol for 3 weeks prior to and during an autumn mating. Doses of 32 and 128 µg daily during mating almost completely prevented pregnancy. The conception percentage during treatment in a group receiving 8 µg was 58, whereas 75% is expected in untreated ewes. This and other evidence indicated that doses as low as 8 µg have adverse effects on fertility. No effect of 8 µg was observed on oestrus, but 32 and 128 µg initially stimulated but later inhibited oestrus. The higher doses had little effect on the average length of oestrous cycles, but increased the variance by causing abnormally long or short cycles. Normal oestrous cycles did not recur in many ewes within 9 weeks of the last injection. However, fertility, the ratio of pregnancies to services, appeared somewhat recovered within about 3 weeks after the last injection. These results indicate that the fertility of Merino ewes is very vulnerable to adverse effects of oestrogen administered during an autumn mating. The significance of this is discussed in relation to possible permanent and temporary oestrogenic effects of subterranean clover pastures, and the importance of losses which may be caused by ingestion of oestrogens during mating.
The analysis of adaptation in a plant-breeding programme
Authors: Finlay KW , Wilkinson GN
Published: November 2004

The adaptation of barley varieties was studied by the use of grain yields of a randomly chosen group of 277 varieties from a world collection, grown in replicated trials for several seasons at three sites in South Australia. For each variety a linear regression of yield on the mean yield of all varieties for each site and season was computed to measure variety adaptation. In these calculations the basic yields were measured on a logarithmic scale, as it was found that a high degree of linearity was thereby induced. The mean yield of all varieties for each site and season provided a quantitative grading of the environments; and from the analysis described, varieties specifically adapted to good or poor seasons and those showing general adaptability may be identified. The study of the adaptation of the whole population of varieties was facilitated by the use of a two-dimensional plot (scatter diagram), with mean yield and regression coefficient as coordinates for each variety. Though wide variation was evident in both mean yield and sensitivity to environment as characterized by the regression coefficient, the variation in sensitivity was proportionately less among varieties with higher mean yield, and the varieties with highest mean yield exhibited, within very narrow limits (regression coefficients close to 0.8), a similar degree of adaptation to all environments over the wide range, especially of seasonal conditions, typical of the South Australian cereal belt. Varieties from particular geographic regions of the world showed a similarity in type of adaptation, which provides a useful basis for plant introduction. Phenotypic stability and physiological and morphological characteristics of groups of varieties with specific or general adaptability are discussed in relation to plant introduction and breeding.
The milk production of merino ewes at pasture
Authors: Lloyd Davies H
Published: November 2004

Milk production for the first 10 weeks was measured in Merino ewes grazed over a 3-year period on native and sown pastures at different stocking rates and under two systems of management; the growth of their lambs was also measured. It did not appear that milk production by the Merino ewe was a limiting factor In growth of single lambs. Lactation curves for the Australian Merino are different from those published for British breeds of sheep. Higher milk production was recorded in ewes: (a) rearing twin lambs as compared with single lambs; (b) rearing single crossbred lambs as compared with single Merino lambs.
Hormonal synchronization of ovulation in beef heifers and fertility after artificial insemination
Authors: Lamond DR
Published: November 2004

After ovarian examination, and enucleation of corpora lutea where possible, groups of beef heifers on farms in the New England region were injected with progesterone in oil for 6 days. This was followed in some experiments by treatment with placental gonadotrophins. Artificial insemination was carried out 3–5 days after the final injection of progesterone. The effects of dose of progesterone, pregnant mare serum gonadotrophin, and human chorionic gonadotrophin on fertility were observed. Fertility was highest in heifers in which the corpus luteum was enucleated prior to injection of progesterone.
Corrigendum - Yield depression due to phosphate fertilizer in sugar-cane
Authors: Yates RA
Published: November 2004

A large series of trials involving phosphate fertilizer showed that yields of cane could be reduced by the application of superphosphate at rates of up to 2 cwt/acre in four distinct areas. In these areas, the yield response to phosphate was dependent on the rate of nitrogen fertilization; yield depression only occurred where the nitrogen supply was adequate; phosphate could increase yields at low nitrogen. In most cases, the yield depression was associated with a low calcium/ magnesium (Ca/Mg) ratio in the soil (a ratio of less than 3.0 in terms of milliequivalents). On soils with high Ca/Mg ratios, regressions of yield response on soil or leaf phosphate indicated critical levels similar to those accepted elsewhere. Significant regressions could not be obtained from soils with low Ca/Mg ratios. A few trials testing a phosphate x trace element interaction indicated that the phosphate yield depression in at least one area was due to an induced deficiency of some trace element. The trace element effect is independent of the Ca/Mg ratio effect.
Rumination in sheep. I. The influence of rumination and grinding upon the passage and digestion of food
Authors: Pearce GR , Moir RJ
Published: November 2004

The nutritional significance of rumination was investigated in relation to certain aspects of rumen function, by using:(a) a chaffed roughage ration on which rumination was either allowed to occur normally or was restricted by means of a muzzle, and (b) a finely ground ration with either the normal rumination or with the addition of polyethylene flakes to stimulate rumination. An apparatus for recording jaw movements was used to measure the extent of rumination. Compared with the chaffed ration, grinding resulted in a shorter retention time of stained particles in the digestive tract, and lower apparent dry matter, organic matter, and crude fibre digestibilities. The addition of polyethylene flakes to the ground ration tended to further decrease retention time and caused a lowering of apparent dry matter, organic matter, and crude fibre digestibilities. The effect of muzzling, to restrict rumination, was to markedly increase the retention time, and this was accompanied by higher apparent dry matter, organic matter, and crude fibre digestibilities than when rumination was not restricted. Supplementary rumen metabolic data are presented. The importance of the mechanical activity in the digestive process is stressed.
Estimates of genetic parameters relevant in selection for certain aspects of egg quality
Authors: Morris JA
Published: November 2004

Thick albumen quality of eggs laid by pullets at the approximate ages of 34 and 64 weeks was measured both for fresh eggs and for eggs stored under reasonably uniform conditions for a period of 14 days. Subsequent analyses provided estimates of heritability of these various traits as well as genetic correlations between them. Heritability was high in all cases except for the 64-weeks measurements on stored eggs. Theoretically, selection based on 34-weeks measurements of albumen quality of fresh eggs should be equally as effective, per generation, as direct selection in improving 64weeks fresh quality. Furthermore, this indirect selection is more effective than direct selection in improving the quality of stored eggs, at both 34 and 64 weeks of age. The heritability of egg specific gravity (used as an indicator of shell thickness) is of intermediate to high value for estimates made both early and late in the pullet year. The genetic correlation between the early and late measurements is high, and selection based on the early measurement should be almost as effective (when assessed per generation) as on the late measurement in causing genetic improvement in late shell quality. All quality traits examined showed positive genetic relationship with each other, although many of the correlations are of low value. The only serious genetic antagonism disclosed was between each of the two assessments of shell thickness and total egg production. There was no evidence of genetic antagonism between albumen quality and total egg production.
The life cycle of Babesia bigemina (Smith and Kilborne, 1893) in the tick vector Boophilus microplus (Canestrini)
Authors: Riek RF
Published: November 2004

The protozoan Babesia bigemina, a cause of tick fever in cattle, is transmitted in Australia by Boophilus microplus. Its development in the lumen of the gut of the tick during the first 24 hr after ingestion remains uncertain. It is believed, however, that most of the forms in the bovine erythrocytes are destroyed, and that only certain oval or spherical bodies survive and develop. These could be gametocytes. Invasion of the epithelial cells of the gut occurs about 24 hr after repletion, and subsequent multiplication of the parasite in these cells is by means of multiple fission. This leads, by about 72 hr, to the production of mature vermicules, which are released into the haemolymph. They measure about 11 µ by 2.5 µ, with a range of 9–13 µ by 2.0–2.9 µ. By about the fourth day, some of the vermicules invade the cells of the Malpighian tubules and of the haemolymph, and a secondary cycle of multiple fission gives rise to vermicules indistinguishable from those that had been produced in the epithelial cells of the gut. Others invade the ova of the tick, and subsequently undergo a similar cycle in the gut cells of the developing larva. The final cycle takes place in the salivary glands of the nymph, and the forms infective to the vertebrate host appear 8-10 days after larval attachment. Multiplication in this cycle is also by multiple fission, but it differs in detail from the preceding cycles. The resultant forms measure 2.2–2.7 µ by 1.0–1.5 µ, and are very similar to the pyriform bodies observed in bovine erythrocytes. Not all ticks develop an infection after engorging on a reacting animal. Infection of the invertebrate host depends, to some degree at least, on the parasite density in the blood of the bovine host. Also, cattle reacting to a tick-transmitted infection are more infective for the tick than those infected by blood inoculation. The vermicule is able to withstand low temperatures, but the earlier developmental stages in the female tick are inhibited by environmental temperature below 20°C. The distinctive characteristics of the vermicule could make this form of value in studies on the epidemiology of bovine babesiosis.
The muscle, fat, and bone content of Angus steer carcasses as affected by stocking rates
Authors: Clark KW , Dudzinski ML , Butterfield RM , Bennett D
Published: November 2004

Data from the complete dissection of carcasses from a selected group of British breed cattle were used to derive regression equations for muscle, bone, and fat on the carcass variables suggested by Butteriield. These equations were used to estimate the carcass composition of 70 Angus steers which had been grazing a Phalaris tuberosa–subterranean clover pasture for 460 days. The regression equations contained data from three of these animals. Muscle was well estimated (R = 0.99) by the equation y = 9.1009–45.0288(fat thickness, cm) + 1.0686(carcass wt., lb)
+ 0.9240(shin muscle wt., Dg). Total bone was estimated (R = 0.99) from the equation y (total bone, g) = –1246.55 + 16.7413(shin bone wt., g) + 4.6399(carcass wt., lb). Fat estimation varied with the nutritional history of the animals. Total fat for animals never subjected to a lengthy stress period could be estimated (R = 0.96) from the equation y = 75.188 + 99.352(fat thickness, cm) + 0.4499(carcass wt., lb). The use of logarithms in the derivation of these equations generally resulted in some improvement in the multiple correlation coefficients. Values were calculated from logarithmic forms of the above equations for the muscle, fat, and bone contents of carcasses from animals which had been grazing at stocking rates of 3/8, 1/2, 5/8, 3/4 and 7/8 of a beast per acre from August 1961 to November 1962. Where the cattle had been grazing alone, both muscle and fat were significantly related to stocking rate but total bone was not. With cattle which had been grazing with sheep, only fat was significantly related to stocking rate. The use of a number of other measurements and the transformation of these variables to logarithmic form is discussed.
Relationship in annual species of Medicago. II. Interspecific crosses between M. tornato (L.) Mill. and M. littoralis Rhode.
Authors: Simon JP
Published: November 2004

Six hybrids were obtained from 212 reciprocal crosses between M. littoralis Rhode and M. tornata (L.) Mill. The hybrids were chlorophyll-deficient in the early seedling stage but later development was normal although growth was retarded. The morphological characteristics were intermediate between those of the parents. Pollen fertility and seed set amounted to 7 and 10% respectively. Meiotic irregularities indicate that M. littoralis is differentiated from M. tornata by at least one translocation. The contribution of the structural changes in the chromosomes accounted for about 60% of the observed pollen sterility.
Transpiration reduction by surface films
Authors: Angus DE , Bielorai H
Published: November 2004

Exploratory tests on the possibility of reducing plant transpiration by means of surface films are described. Cetyl alcohol reduced transpiration significantly, but also caused considerable damage to the plants. Low viscosity silicone oils reduced transpiration by up to about 50%, and caused only marginal growth abnormalities. Comparison of the present data with other work where film-forming materials were added to the root medium of plants suggests that foliar application is preferable to root application.
The fate and effects of duodenally infused casein and urea nitrogen in sheep fed on a low-protein roughage
Authors: Egan AR
Published: November 2004

Urea and casein infused per duodenum into sheep fed on a low-protein cereal hay produced elevated blood urea and rurninal ammonia concentrations. Compared with casein infusion, urea treatment resulted in greater and more rapid rises in both blood urea and ruminal ammonia concentrations. Cellulose digestion rates were increased after infusion of either material, but casein tended to exert its effect at a later time. Of 10 g of nitrogen infused in each form, urinary excretion accounted for 5 g with urea treatment, but only 3 g when casein was given. Results are discussed in relation to mechanisms for conservation of urea nitrogen in sheep fed on low-protein diets. Attention is drawn to the implications of these findings in relation to the effect of casein infused per duodenum upon voluntary intake of low protein roughages.
Nutritional status and intake regulation in sheep. II. The influence of sustained duodenal infusions of casein or urea upon voluntary intake of low-protein roughages by sheep
Authors: Egan AR
Published: November 2004

In each of two experiments, casein dissolved in 1% disodium hydrogen orthophosphate given daily to sheep per duodenum increased the intake of the roughages offered. Results in each experiment were compared with those of infusions of equivalent volumes of phosphate solution alone. In experiment 1, casein (4.5 g nitrogen/day) infused per duodenum resulted in a 42% increase in intake of a chaffed oaten hay (0.56% nitrogen) diet. Mean retention time of food in the alimentary tract was not altered, but the digestibility of the dry matter and the rate of cotton thread digestion in the rumen were depressed. Urea (4.5 g nitrogen/day) given per duodenum gave a 12% increase in intake, associated with a greater rate of cotton thread digestion in the rumen, and a consistently shorter mean retention time of residues in the alimentary tract. Evidence suggested a greater amount of dry matter in the gut when casein was given but not when urea was given. Nitrogen balance was improved from negative values to positive values by both casein and urea infusions. In experiment 2, a diet of wheaten straw supplemented with 3% urea was offered. Under these conditions, casein (6 g nitrogen/day) improved nitrogen balance and produced an average increase of 11% in daily dry matter intake. Rates of cotton thread digestion, digestibility of dry matter, mean retention time, and number of rumination chews were all unaltered by casein infusion. Results from both experiments are discussed in relation to current hypotheses of the mechanisms for regulating roughage intake in ruminants. A possible role of protein status of the animal in influencing the amount of dry matter which is held in the alimentary tract under ad libitum feeding conditions is suggested.
Nutritional status and intake regulation in sheep. IV. The influence of protein supplements upon acetate and propionate tolerance of sheep fed on low quality chaffed oaten hay
Authors: Egan AR
Published: November 2004

Under ad libitum feeding conditions, injected acetate disappeared more slowly from the blood of sheep fed on a diet of low protein oaten chaff than when 6% casein was added to the diet. Only 2 days after the sheep were changed from the high to the low protein diet, the rate of disappearance of injected acetate dropped considerably. An equally rapid rise occurred when the sheep were changed from the low to the high protein diet. After receiving casein per duodenum for 3 days, sheep fed ad libitum on low quality oaten chaff improved in their ability to cope with injected acetate.Propionate tolerance was rapidly improved when sheep were transferred from a low quality oaten chaff diet to one supplemented with casein, each offered ad libitum. The changes in ability to cope with acetate load are discussed in relation to possible mechanisms concerned, and a physiological mechanism of regulating voluntary feed intake is suggested. It is emphasized that further investigations are needed of the effect(s) of the nature of the diet upon the sheep's ability to utilize the metabolizable energy at ad libitum intake, particularly upon the avenues and efficiency of acetate utilization.
Body compostion in vivo. VIII. Some physiological implications with respect to extracellular fluid volume arising from the distribution of thiocyanate in sheep
Authors: Panaretto BA
Published: November 2004

The distribution of [35S]-thiocyanate in sheep was studied. The specific activity in rumen fluid during the first 4 hr after injection was markedly less than in serum, and equilibration between rumen fluid and blood was not reached until 20–30 hr after injection. There were large urinary losses of the marker and approximately 50% of the dose was lost in 24 hr. Activity in rumen fluid and urine was due to [35S]-thiocyanate. The thiocyanate spaces, allowing for urinary losses, during the first 4 hr after injection were 25 –30% body weight, increasing to 35–40% body weight at 20–30 hr after injection. The physiological implications of the results with respect to measuring extracellular fluid volume in sheep are discussed.
The toxicity of Indigofera enneaphylla L. in rats
Authors: Murray LR , Moore T , Sharman IM
Published: November 2004

The inclusion of 50% of dried Indigofera enneaphylla in the diet arrested the growth of young male albino rats, caused incoordination of their limbs, and was fatal to them. Microscopic evidence of liver cellular abnormality was consistently observed in rats fed on the plant. Chemical analysis of I. Enneaphylla indicated the presence of combined G-nitropropionic acid, paralleling the findings of other workers in respect of I. Spicata, which, in addition, produced liver lesions. Dried I. Enneaphylla contained about 12 p.p.m. of α-tocopherol. According to haemolysis tests, the poisoned rats were not deficient in vitamin E. The administration of liberal doses of α-tocopheryl acetate did not counteract the poisoning. In preliminary experiments, dosing with L-arginine appeared to be partially protective against poisoning by I. Enneaphylla. Autoclaving the dried plant, according to a single feeding trial, resulted in loss of toxicity.
The effect of photoperiod on flowering, growth habit, and dry matter production in four species of the genus Stylosanthes SW
Authors: t Mannetje L
Published: November 2004

S. humilis H.B.K., S. guyanensis (Aubl.) Sw. subsp, guyanensis, S. mucronata Willd., and S. montevidensis Vog. were subjected to photoperiods of 8,10,12, and 14 hr in the CSIRO Phytotron in Canberra. S. guyanensis and S. humilis appeared to be short-day plants and S,.montevidensis a long-day plant for flowering. S. mucronata showed a rather indefinite response, but appeared to flower more rapidly under short days than under long days. Under photoperiods of 8 and 10 hr, S. humilis had a prostrate habit and S. montevidensis plants were stunted, while under photoperiods of 12 and 14 hr both species grew erect. S. guyanensis and S. mucronata showed no differences in growth habit with photoperiod. Dry matter yields for the 12 and 14 hr photoperiods were significantly larger than those for the 8 and 10 hr photoperiods for all species except S. mucronata, which gave a significantly higher yield only under the 14 hr photoperiod.
Wether bioassay of annual pasture legumes. IV. The oestrogenic activity of annual medic pastures
Authors: Francis CM , Millington AJ
Published: November 2004

The oestrogenic activity of seven medic pastures measured at the time of flowering , by wether bioassay was highly correlated with their coumestrol content. The most active varieties M. littoralis (Harbinger) and M. truncatula (Cyprus) produced wether teat length increases equivalent to those resulting from injection of 8 µg of stilboestrol daily. M. scutellata (snail medic) and M. polymorpha (common burr medic) had no measurable activity. Medic pastures had only low coumestrol contents in the pre-flowering stages. Dry annual medic swards had greater coumestrol contents than the green pastures. At the burr development stage most coumestrol is found in the mature leaves, with only relatively insignificant quantities in the stems and pods. In dry material, however, the stems and pods had very high coumestrol contents. A table is presented of the coumestrol content of representative medic species tested at the flowering stage.
Seasonal variation in fertility in Merino ewes : the reproductive wastage associated with mating in winter, spring, summer, or autumn
Authors: Watson RH , Radford HM
Published: November 2004

Merino ewes of four groups were joined for mating in winter, spring, summer, or autumn. Each group remained with the rams for 8 weeks. Some of the ewes were examined at autopsy 4 weeks after mating, others radiographically 12–18 weeks after mating, and others were allowed to lamb without interference. Some ewes failed to mate in winter and many in spring, but virtually all mated in summer and autumn. In spring, but not in other seasons, some rams served more ewes than others. In winter, but again not in other seasons, the incidence of mating was related to the physical condition of the ewes. Absence of mating, both in winter and spring, was due to ovarian inactivity. There was significant variation between rams in returns to service and in foetal loss 4 weeks after mating. Where fertility of rams was not implicated there was no significant seasonal variation in foetal loss at 4 weeks; this averaged 13% and there was little foetal loss thereafter. Lamb losses were high from ewes mated in summer or autumn but low from those mated in winter or spring.
Studies on frost injury to wheat. III. Screening of varieties for resistance to ear and stem frosting
Authors: Single WV
Published: November 2004

A technique for freezing plants in pots has been evolved to test the resistance of different varieties of wheat to frost during the phase of stem elongation prior to ear emergence.Significant positive correlations were established between the results of this test and the performance of 18 varieties in two field trials, as determined by counts of tiller mortality after severe frosts. Screening tests with 430 early-maturing spring wheats showed that variation in resistance between varieties is restricted, but of sufficient magnitude to be considered by plant breeders working in frost-liable areas.