bluuebunny/crossref_metadata_2025 huggingface dataset:
The artificial insemination of the Merino sheep following the synchronization of oestrus and ovulation by progesterone injected alone and with Pregnant Mare Serum Gonadotrophin (PMS)
Authors: Robinson TJ
Published: November 2004

Two groups (2 and 3), each of 112 stud Merino ewes, which were experiencing regular oestrous cycles, received daily injections of 10 mg progesterone for 16 days, in an attempt to synchronize oestrus and ovulation for artificial insemination. One group (3) received an additional injection of 500 i.u. pregnant mare serum gonadotrophin (PMS) the day after the final progesterone injection. Injections were staggered so as to bring between 15 and 20 ewes of each group into oestrus on each of six days, on which days approximately equal numbers of untreated oestrous ewes were inseminated (group 1). In group 2 (progesterone alone), 104 ewes were teased and inseminated within 4 days of the final injection, including 74 (71 per cent.) on the third day. Corresponding numbers of ewes for group 3 (progesterone-PMS) were 107, 96 (90 per cent.). Injection of PMS significantly advanced and improved the precision of time of onset of oestrus, and presumably of ovulation. Of 315 ewes inseminated in all groups, 265 received 0.10 ml undiluted semen; 33, 0.05 ml; and 17, 0.20 ml. There were no apparent differences in lambing rate. Ewes inseminated, ewes lambing, and lambs born were: group 1, 104, 58 (55 per cent.), 74 (71 per cent.); group 2, 104, 53 (51 per cent.), 64 (62 per cent.); group 3, 107, 61 (57 per cent.), 85 (79 per cent.); overall, 315, 172 (55 per cent.), 223 (71 per cent.). There were no significant differences between groups in the proportion of ewes which lambed, or in the twinning rate. Ewes in oestrus and inseminated 72 hr after the final injection of progesterone had a significantly higher lambing rate than did ewes inseminated a day later. It is concluded that progesterone, particularly if used in conjunction with PMS, is of value in synchronizing oestrus in the breeding season for precisely planned artificial insemination.
The effect of associate perennial grasses on a simple pasture mixture of phalaris and subterranean clover
Authors: Andrew WD , Neal-Smith CA
Published: November 2004

Over the period 1952-1954 there was no significant difference in the yield of herbage produced annually by the addition to a Phalaris tuberosa L.–Trifolium subterraneum L. pasture mixture, of any one of the following grasses: Agropyron obtusiusculum Lange., Bromus coloratus Steud., Bromus inermis Leyss., Dactylis glomerata L., or Festuca arundinacea Schreb. There were indications of a small change in seasonal production where certain grasses, notably D. glomerata, were included in the mixture. Over the 3-year period the proportion of the sown grass component, in the mixtures where either D. glomerata, B. inermis, or B. coloratus were included, increased by a greater amount than where the simple mixture of phalaris and subterranean clover was used. The addition of each grass also lessened the amount of P. tuberosa in the sown grass component of the yield. In the third year, despite the varying proportions of the phalaris and associated sown grass species, the mean population of the sown perennial grasses in each treatment did not differ significantly from the mean figure of 1.34 plants/sq. lk. The increased production of the sown grass yield component following the association of certain of the above species with P. tuberosa suggests that the latter does not fully exploit the environment. The principle of including another perennial grass when sowing phalaris and subterranean clover might have wide application as a means of combatting "phalaris staggers".
Studies on the effect of malachite green on Potato viruses X and Y
Authors: Thomson AD
Published: November 2004

A study has been made of the effect of malachite green on potato viruses X and Y using Dakota Red and Aucklander Short Top potato shoot apices in tissue culture. No plants have been freed from either virus X or Y and there has been no statistically significant effect of the dye on virus X concentration as indicated by local lesion counts on Gomphrena globosa L. Malachite green either sprayed on the leaf surfaces or watered on the soil had no effect on the systemic spread of a ringspot isolate of virus X inoculated to Nicotiana glutinosa L.
The effect of high air temperature on pregnancy and birth weight in Merino sheep
Authors: Yeates NTM
Published: November 2004

During the winter of 1954, 21 pregnant Peppin strain Merino ewes were subjected daily, 7 hours a day, 7 days a week, to an air temperature of 105°F dry-bulb, 92°F wet-bulb, in a psychrometric room. Nine of the ewes were heated from the date mating started and the other 12 from the 38th day of pregnancy. Birth weights of the lambs of the two groups showed no significant difference from those of 10 unheated control ewes pregnant during the same period. However, when subjected the following year, for the same period daily throughout the whole of pregnancy, to a higher temperature, namely, 112°F dry-bulb, 98°F wet-bulb, 10 experimental ewes produced lambs having a mean birth weight 1 lb 13 oz less than that of the lambs of eight unheated control ewes. The difference is highly significant statistically. It is concluded that pregnancy in Merinos is adversely affected by extremely high atmospheric temperature; and that this could well explain the low birth weight of lambs born following a summer gestation in tropical Queensland and in certain other parts of Australia when an unusually hot summer occurs.
Seasonal fluctuations in the nitrogen content of the sultana vine
Authors: McEAlexander D
Published: November 2004

Estimates were made of dry matter and nitrogen contents of parts of sultana vines sampled a t frequent intervals from October to January in one season and January to July in the following season. From early October until the commencement of leaf drop in February there was a linear increase in the amount of nitrogen in the annual aerial growth. This nitrogen was present mainly in the laminae and fruit. After February the amount of nitrogen in the fruit continued to increase while that in the leaves decreased. The loss from the leaves could be partly accounted for by translocation to fruit or woody tissues and the remainder by leaf fall. The data obtained gave no indication of the best time for applying nitrogen to sultana vines. The amount of nitrogen in stems, and also the percentage of nitrogen in trunks, main roots, and feeder roots, increased to July, which suggested that root absorption from the soil continued throughout autumn. It is suggested that the total nitrogen content of laminae gives the most reliable indication of seasonal nitrogen uptake provided that due allowance is made for time of sampling. '
The heat balance of sheep standing in the sun
Authors: Priestley CHB
Published: November 2004

An extension is made of Lee's (1950) original discussion of the heat balance of sheep exposed to a tropical sun. Methods are given for calculating the two quantities, convective heat loss and long-wave radiation exchange, which automatically compensate to a large extent for the added heat load. There appear to be advantages in distinguishing between the heat balance of the fleece and that of the body of the sheep, and this provides a method of estimating the heat conducted to the body as a consequence of the insolation.
The value of faecal nitrogen and faecal crude fibre in estimating intake of four subtropical grass species
Authors: Milford R
Published: November 2004

For each four subtropical grasses there is a significant correlation between daily dry matter intake and total nitrogen in faeces per day. The data have been tested for homogeneity under two hypotheses. In the first a test of the difference in slope between the four regression lines showed that they were not statistically different. It was shown that for a common mean value for total faecal nitrogen, the calculated mean daily dry matter intakes of Paspalum commersonii Lam., Urochloa pullulans Stapf, and Chloris gayana Kunth were similar and the relationship for these three could be expressed by one regression line. However, the calculated mean daily dry matter intake for Panicum maximum var. trichoglume (K. Schum.) Eyles was significantly different from those for the other three grasses and P. maximum var. trichoglume cannot be included in a general regression. In the second hypothesis it was shown that all regression lines could pass through the origin. However, as in the first hypothesis, P. commersonii, U. pullulans, and C. gayana could be represented by a common regression line whllst the regression line for P. maximum differed significantly in slope from those of the other three grasses. The results indicate that species can be grouped for this relationship, and that it could be used to measure intake of the free grazing animal on monospecific swards or on mixed swards of species with similar relationships. Lancaster's technique for determining digestibility is discussed in the light of these relationships. Neither percentage faecal nitrogen nor faecal crude fibre was found to be satisfactorily correlated with dry matter digestibility.
Methionine supplements in chicken diets. II. A breed difference in growth response to DL-methionine
Authors: McDonald MW
Published: November 2004

In four experiments, White Leghorn chickens showed a highly significantly (P < 0.01) greater response in early growth following addition of DL-methionine to a practical basal diet, than Australorp chickens. Average increases in body weight were: White Leghorns, 10.95 per cent.; Australorps, 2.0 per cent. In crosses between these breeds, it was shown that the difference between the breeds can be explained by a single sex-linked gene or group of genes, dominant in White Leghorns. Possible biochemical bases for the breed difference are discussed.
Photoperiodicity in cattle. II. The equatorial light environment and its effect on the coat of European cattle
Authors: Yeates NTM
Published: November 2004

Thirteen European cattle have been maintained for periods of up to 21 months in a light environment artificially adjusted to provide 12 hr 50 min of light daily, so simulating the equatorial photoperiod. The initial coat reaction of several groups of these animals differed according to the season in which they entered the experiment. Thus transfers in the spring and autumn were followed by complete shedding; those in winter by a rapid partial shed; and those in the summer by rapid growth of hair. On adaptation to the new environment, however, all the groups eventually grew, and thereafter permanently maintained, a similar coat, characterized by intermediate length and furry appearance. The experiments show that the equatorial photoperiod eliminates the natural coat cycle of European cattle, and that it tends to maintain them in a heat-retaining type of coat.
The phytotoxic and fungicidal effects of Sodium o-Phenylphenate in controlling green mould wastage in oranges
Authors: Long JK , Roberts EA
Published: November 2004

Solutions of sodium o-phenylphenate control green mould wastage sue to (Penicillium digitatum) but can cause rind injury in oranges. Data are given on the effects of varying concentrations and pH levels of sodium o-phenylphenate solutions, duration of dip, rinsing, and the addition of hexamine. The occurence of rind injury is due to the absorption of o-phenylphenate and the effectiveness of waste control depends on the levels of both sodium o-phenylphenate and o-phenylphenate. The degree of rind injury depends primarily upon the concentration of o-phenylphenate in the solution, which can be controlled by pH adjustment. Accordingly, an explanation of the role of hexamine is given. Sodium o-phenylphenate control of mould wastage is superior to control by borax-boric acid.
Seed-Setting in subterranean clover (Trifolium Subterraneum L.). II. Strain-environment interactions in single plants
Authors: Yates JJ
Published: November 2004

The relationship between seed-setting (expressed as mature seeds per
inflorescence), strain, and environment was investigated in subterranean clover,
with special reference to burr burial. Single plants of a range of maturity types were grown in two environments, one cool and moist, the other hot and dry but with frequent watering of the plant roots. In the mild environment, early-maturing strains buried a high proportion of burrs, and late-maturing strains relatively few. Under the more severe conditions, late-maturing types buried the majority of their burrs. Seed-setting in buried burrs was generally good, and relatively constant in all the strains and the two environments tested. The capacity to set seed above the ground varied widely amongst strains, and within each strain was greater in the
mild environment. The results indicate that seed-setting is influenced strongly by the microenvironment of inflorescences and developing burrs, and that strains differ in sensitivity to such microenvironment. Burr burial is apparently a protective mechanism against unfavourable factors (probably low relative humidity and high temperature) of the atmospheric environment.
Under the more severe environmental conditions, there was a positive correlation between seed-setting above the ground and percentage leaf in the plant tops. It is presumed that this was due partly to amelioration of the microenvironrnent by the foliage. The negative relationship between efficiency of seed-setting above the ground and proportion of burrs buried is discussed in terms of natural selection. The microenvironmeilt, and the differential response of strains, affected not only the number of seeds per inflorescence, but also the weight and viability of the
seeds produced. The concept of a threshold embryo weight for viability is discussed.
The role of selection in the improvement of Welsh Mountain sheep
Authors: Doney JM
Published: November 2004

Means and variances of several economic characters in Welsh Mountain sheep are given. The repeatabilities of, and phenotypic correlations between, these characters are generally within the range of similar estimates given for other breeds. Heritabilities, calculated from parent-offspring correlations, were : birth weight 0.39, weaning weight 0.68, 18-month weight 0.59, greasy fleece weight 0.61, and staple length 0.73. These values are in general higher than similarly derived estimates from other breeds. A method of correcting heritability estimates to remove the error due to correlation between maternal environment, and the character as measured in the dam, is described. This reduces the estimate for weaning weight to 0.48, and that for 18-month weight to 0.16, but does not change that for fleece weight. The use of such estimates in predicting the effect of selection is discussed, and it is concluded that accurate selection for the chosen economic characters will result in improvement at the present genetic stage of the breed.
The summer nutrition of weaner sheep: The relative roles of available energy and protein when fed as supplements to sheep grazing mature pasture herbage
Authors: Allden WG
Published: November 2004

In a field experiment of factorial design, concentrate supplements of cereal origin were fed to 16 groups each of eight young Merino wethers. These sheep grazed the mature herbage of Phalaris tuberosa L.-subterranean clover (Trifolium subterraneum L.) sown pastures during summer in the Mediterranean environment of Adelaide, South Australia; and under conditions of common grazing, sheep in the different treatment groups were each day individually fed rations which varied in content of available energy and of digestible nitrogen (protein). The daily allowances of energy were 48, 113, 227, and 340 g total digestible nutrients (T.D.N.), and of digestible nitrogen either 2.5, 5.0, 7.5, or 10.0 g. In addition there was a control group which received no supplement. No interaction was observed between the energy and the nitrogen portion of the supplement, each constituent having its independent effect in terms of both body weight gain and wool growth. Responses to changing energy were linear for both wool production and body weight gain. The effect on wool production of increasing protein was also linear, but the gain in body weight with each increment of protein progressively decreased, which suggested an approach to an asymptotic value. It is concluded that for body weight gain mature herbage may be deficient in both available energy and protein, but once a small need for protein is satisfied energy becomes a limiting factor. In terms of wool production summer pastures are deficient in both protein and energy, the latter constituent making a notable contribution in influencing nitrogen retention.
The total number of fibres on sheep. I. Estimation by clean fleece and fibre weight
Authors: Doney JM , Weiler H
Published: November 2004

The total number of fibres on sheep (NT) is calculated by means of the formula NT = WT /w, where WT is the clean fleece weight and w the mean clean fibre weight. WT is obtained by multiplying the greasy fleece weight by an estimate of the yield, and w is estimated from samples of scoured wool. The variation over the sheep's body of yield and mean clean fibre weight was investigated and the accuracy of the estimate of total fibre number was deduced. It was found that mean clean fibre weight showed no consistent trend over the body and that the trend in yield was small.
The long-tailed mealybug, Pseudococcus adonidum (L.) in South Australia
Authors: Browning TO
Published: November 2004

The numbers of the long-tailed mealybug, P. adonidum (L.), on irrigated orange trees in South Australia rise and fall in a fairly regular sequence throughout the year. They are always low in summer, rise in autumn and early winter, and begin to fall gradually in late winter and spring. There is a sudden sharp rise in November followed almost at once by an equally sharp fall to the numbers characteristic of summer. This sequence may be explained in terms of the influence of weather on the survival and multiplication of the mealybugs in relation to the place where they happen to be living, the influence of predatory insects, and the behaviour pattern of the species. Food seems to play no part in this sequence except as its quality may influence behaviour. During summer the majority of the mealybugs on the leaves are to be found in specially sheltered places, such as under spider webs. There is evidence that the special quality of these places that makes them suitable for mealybugs is the greater humidity there than elsewhere. Young mealybugs on hatching are active in summer and tend to leave the shelter in which they originated and are likely to perish before they find another suitable place. At this time there are relatively few predatory insects. As autumn approaches the becomes cooler and less desiccating, and although the reproductive rate may fall the chance that young mealybugs will survive increases. This continues until the cold of winter reduces the reproductive rate to the point where it can no longer compensate for deaths and the population begins to fall. At the same time predatory insects become more numerous and take a greater toll of the population, forcing numbers still further down. In early spring the insects stop feeding and seek a sheltered place in which to reproduce. The migration from the leaves to the trunk and ground gathers momentum during September and October until the numbers left on the leaves are very low. At this time predatory insects become more numerous than they have been and the numbers of sheltering mealybugs may be greatly reduced. Then in November a new generation is produced which invades the leaves but most of these are killed quite soon by the hot dry winds which are common at this time of the year. The population falls to a low level and remains so until autumn.
Migration of pedigree Jersey cattle in Australia
Authors: Barker JSF , Allingham DH
Published: November 2004

Australia has been divided into 13 climatic regions. One hundred heifers and 50 bulls were taken at random for each region, their two-generation pedigrees traced, and the origin of each ancestor noted. Immigration is higher for the male sample than for the female. The genetic replacements (percentage of genes brought into the region during one generation) are 34.7 and 24.1 per cent. respectively. The replacement indices (percentage of each type of ancestor bred in a different region) are 53.3 and 38.1 for sires of the male and female samples respectively and 16.0 and 10.1 for dams, which indicates that migration is higher for sires than for dams. Regions 3 (semi-coastal Queensland), 7 (central coast, New South Wales), and 10 (Gippsland, Victoria) are the main breeding regions. Regions 11 (southwestern Victoria and South Australia), 12 (Tasmania), and 13 (Western Australia) have low immigration rates and are consequently semi-isolated from the rest of the breed. Within these semi-isolated regions, however, movement is highest. Further, although there is considerable migration between the four regions of Queensland (regions 1-4), the Queensland group is semi-isolated from the rest of the breed. Between region migration is mainly between adjacent regions, with some migration into all regions from the main breeding regions. All regions export and import bulls except region 12 (Tasmania,) and region 13 (Western Australia). The number of Breeders' Herds (herds supplying sires to other pedigree herds) is mainly a function of the number of herds within a region. The migration rate in the Australian Jersey appears to be considerably less than in Friesians, Shorthorns, or Ayrshires in the United Kingdom. Since most migration is between adjacent regions, this low rate of migration and geographic isolation together favour the development of semi-isolated and therefore possibly locally adapted strains. It is suggested that this pattern should he maintained until the importance of genotype-environment interactions is determined.
Seasonal variations in wool growth and heat tolerance of sheep. I. Wool growth
Authors: Wodzicka M
Published: November 2004

The monthly wool growth of three groups of rams was studied at Beltsville, Maryland. Group I received natural daylight (at 38° 53' N.) and was shorn monthly. Group II had a 7:17 hours of daylight to hours of darkness rhythm and was shorn every 6 months, once in winter and once in summer. Group III received natural daylight and was likewise shorn every 6 months. The rams of all groups produced more wool in summer than in winter. This difference was significant (P<0.001). The mean body weight and food intake were both greater in the winter months, which indicated that the seasonal rhythm of wool growth was not a consequence of poorer feeding in winter. The rams which were shorn monthly (group I) grew considerably more wool than the other two groups, but the difference was not statistically significant. The short-day treatment of group II did not increase the annual wool production nor decrease the seasonal rhythm of wool growth. The balance of evidence from this and other experiments indicates that temperature rather than light controls the seasonal rhythm of wool growth.
Some experimental observation on the toxicity of urea to sheep
Authors: Coombe JB , Tribe DE , Morrison JWC
Published: November 2004

The rumen pH and ammonia nitrogen levels were recorded in sheep fed on different amounts of urea in different ways. It was found that when the urea was sprayed onto the daily intake of roughage these levels remained low, even when intakes of 100 g urea were obtained, compared with the levels recorded when lower levels of urea (25 g) were given as a drench. As the rumen pH level rose to 7.0 and above, the periods of time spent ruminating declined until at about a pH of 7.3 complete rumen stasis occurred. The stasis did not occur at higher levels of rumen ammonia nitrogen provided that the pH level was kept down. Sheep readily consumed large amounts (up to 100 g) of urea per day provided that the concentration of urea in the ration did not exceed 6 per cent.; when this happened the food intakes were markedly reduced. A theoretical explanation is offered of the influence of the rumen pH level on the rate of ammonia absorption from the rumen.
Studies on the carbohydrate metabolism of sheep. X. Further studies on hypoglycaemia and hyperketonaemia in undernourished pregnant ewes and in ewes with pregnancy toxaemia
Authors: Reid RL
Published: November 2004

Data on blood glucose, ketone, and acetic acid values have been obtained over a period of several years from field cases of pregnancy toxaemia and from cases induced experimentally and their controls. When feed intake is controlled, differences between blood glucose and ketone levels in ewes moderately undernourished in late pregnancy are largely dependent on the number of foetuses. The consistency of these differences often allows accurate diagnosis of multiple and single pregnancies. Differences in blood glucose between undernourished monotocous and polytocous ewes disappear when undernutrition becomes severe or in the early stages of fasting after a period of moderate undernutrition. Differences in blood ketones tend to be maintained even after several days of fasting. The level of blood ketones during fasting depends on the previous level of nutrition of the ewe; blood glucose is unaffected by previous level of nutrition. The frequent presence of persistent normoglycaemia in ewes with pregnancy toxaemia is discussed in the light of data presented; it is concluded that the onset of pregnancy toxaemia often occurs in the presence of normal blood glucose levels. Blood volatile fatty acid (V.F.A.) levels are often high in those cases of pregnancy toxaemia which occur largely as a result of severe under nutrition in late pregnancy, in spite of an almost empty rumen. Only acetic acid was detected in six blood samples examined; this is considered to be of metabolic origin, but there is no consistent relationship with blood ketone level. The usual clinical syndrome of pregnancy toxaemia can be classified as acute or subacute. In the latter, cerebral depression reaches a certain stage of severity which is then maintained, survival is often prolonged, and ewes do not become comatose before death. Cases of pregnancy toxaemia induced by under nutrition alone usually show the acute syndrome. Blood ketones are higher in such cases than in fasted ewes showing no clinical signs; the critical blood ketone level appears to be about 30 mg per 100 ml. Cases induced in previously well-nourished ewes by fasting in association with a severe environmental stress are usually subacute; blood ketones are no higher than in ewes not showing clinical signs and are often considerably below 30 mg per 100 ml. The significance of these observations is discussed.
Control of the time of ovulation in sheep
Authors: Braden AWH , Lamond DR , Radford HM
Published: November 2004

Synchronization of ovulation in ewes during the breeding season was achieved by a 14 day course of progesterone injections followed by injections of pregnant mare serum gonadotrophin (PMS) and human chorionic gonadotrophin (HCG). Optimal control was attained when the PMS was given at the time of the last progesterone injection and the HCG 24 hr later. With this treatment most ovulations occurred between 20 and 28 hr after the HCG injection. However, none of the ewes exhibited oestrus at this time. Greater variability in the time of ovulation was found when the progesterone-PMS and PMS-HCG intervals were 0 hr and 48 hr, or 24 hr and 24 hr, and with these treatments about 80 per cent. of the ewes exhibited oestrus just before ovulation. On the 0-48 hr treatment schedule with artificial insemination 3-7½ hr after the HCG injection, 13 of 22 ewes had fertilized eggs or embryos when killed 3 or 35 days later.
Hornedness and polledness in sheep. II. The inheritance of horns in Merino ewes
Authors: Dolling CHS
Published: November 2004

Observations have been made on Merinos of the medium Peppin, medium non-Peppin, and strong non-Peppin strains. The appearance of true horns in ewes in a large medium Peppin flock has been shown to result from the action of a dominant autosomal gene designated P'. Both P'P' and P'p ewes grow horns approximately 5–12 in. long when adult, while pp ewes have either bone knobs or short, loose sours growing on their horn sites. The frequency of P' in one medium Peppin flock observed is 0.11. No expression of P' in the entire male has been demonstrated, possibly because of the great effect of the male sex hormones on horn growth in rams.
A study of some carbohydrate relationships in the wheat plant and of wheat starch extracted from mottled and unmottled grain
Authors: Wood HL
Published: November 2004

Sucrose is the dominant accumulated carbohydrate in the wheat plant until approximately 4 weeks before harvesting, when starch takes this position. Starch is the dominant carbohydrate in the grain. Total reducing sugars are never accumulated in large amounts in any portion of the plant. The mature mottled grain contains significantly more starch and less protein than the unmottled. The developing grain from an area known to produce mottled wheat is always higher in starch and lower in protein when compared with grain from an unmottled area. Irrespective of variety and whether the grain is mottled or not, starch extracted from the mature grain contains 22.4 per cent. amylose, and there appear to be no major differences between the starches extracted from the respective grains. It is probable that while the ratio of amylose to amylopectin is set by heredity, the molecular size of these components varies as starch is laid down in the developing grain.
A pedological study of phosphorus in 12 soils derived from granite
Authors: Wild A
Published: November 2004

Chemical analysis of 12 soil profiles on granite showed that all except two had lost phosphate by leaching. The loss of phosphorus from each profile is calculated in grams per sq centimetre of profile surface, and as a percentage of the amount originally present. Three methods of calculation are used, each being based on one of the following assumptions as to the changes which take place on rock weathering: that there is (a) no change in weight, (b) no change in volume, (c) no loss of zirconium. The three methods are generally consistent in showing which soils are the most leached and which are the least leached. The estimated loss of phosphorus from each profile depends on which assumption is made. There is no simple correlation between the loss of phosphorus and the present rainfall. Reasons which are suggested are that the soils differ in age, in level of organic matter, and possibly in the rates of weathering of the parent rocks. Up to two-thirds of the phosphorus retained in the soil is chemically bound by the free oxides of iron and aluminium.
The effect of a 'Diazinon' formulation on the oviposition behaviour of the Australian sheep blowfly (Lucilia cuprina).
Authors: Browne BB , Norris KR
Published: November 2004

Females of Lucilia cuprine (Wied.) avoid laying on areas of fleece treated with a 'Diazinon' formulation. This effect, which continues for several weeks after the application of the insecticide to the sheep, is due to the solvent ('Stanvac PY') used in the formulation. Power kerosene, when used as a solvent, has less effect. Evidence is given that the solvents act as oviposition deterrents, but show no significant repellency. 'Diazinon' toxicosis plays no part in the observed effects.
The effect of aging on the biological efficiency of some DDT cattle-dipping formulations.
Authors: O'Neill DK , Alexander AE
Published: November 2004

Bush ticks (Haemaphysalis bispinosa Neumann) were used to compare the biological efficiency (toxicity) and amount of DDT deposited from suspensions of four formulations of DDT normally used for dipping cattle. The effects of aging and the addition of bentonite clay and of salt on the suspensions were measured over periods of 28 days: three formulations which were of the supercooled melt type changed in toxicity and deposit on aging whilst the fourth formulation-a dispersible powder-did not alter appreciably. It is suggested that the low concentration of soaps (i.e. surface active agents) in the latter made it relatively immune to aging and the effects of bentonite and salt. In the supercooled melt formulations, wherein the concentrations of soaps were very much greater, the changes are ascribed to DDT crystal growth and aggregation, which in turn are governed by the nature and amounts of soaps present. The formulation containing sulphated butyl oleate gave the greatest deposit, with a maximum occurring at about 14 days, whereas the toxicity increased progressively on aging. The two other supercooled melt formulations contained undisclosed mixtures of anionic and non-ionic soaps; although the deposits increased, no maximum occurred within the aging period. The amounts deposited were similar to but not as large as those from the first formulation. The addition of bentonite and salt lowered both deposits and toxicities. It is suggested that bentonite adsorbed the soaps, thereby retarding crystal growth, and also became adsorbed on the DDT surfaces, thereby stabilizing the suspensions. The concentration of added salt was such that it stabilized the suspensions and resulted in DDT crystal sizes giving lower deposits and hence lower toxicities. The effect was most marked with the formulation containing sulphated butyl oleate. It is suggested that the hydrophobic surface of the tick is important in the attachment of DDT particles, the amount retained on dipping depending largely upon crystal size and degree of aggregation. Correlation between the in vitro tests and field performances of the formulations is discussed.
Relationships among clean wool weight and its components. 2. The effect of maternal handicap and its influence on selection.
Authors: Turner HN
Published: November 2004

The average difference in clean wool weight between handicapped (twins and the progeny of young ewes) and unhandicapped (singles, the progeny of adults) animals of both sexes, born in the same year, was -0.34 � 0.07 lb (365 days' growth shorn at 16 months of age). 87% of the difference in wool weight arose from a difference in total number of fibres (or follicles) per sheep, the difference in output per follicle being negligible. Body weight, wrinkle score, and follicle population density were all lower in the handicapped animals. The difference in total follicle population arose from a deficiency in secondary but not in primary follicles. If the handicapped animals are not identified at selection, they will suffer a heavier culling rate if selection is on fleece weight, and estimates of differential culling rates are given. The effect on genetic progress and current production is, however, negligible with a handicap of this size. In fact, when the handicapped animals are twins, there are more animals available for selection than there would have been if the births had been single, and the higher selection differential arising from the smaller proportion saved more than offsets any deficiency from the handicap. The main effect of not identifying handicapped animals at selection is that twins will be selected against, with a resultant lowering of the twinning rate. The suggestion is made that management might possibly overcome the handicap, at least in part.
Environment and sporulation in phytopathogenic fungi. III. Peronospora tabacina Adam: Field environment, sporulation, and forecasting
Authors: Rider NE , Cruickshank IAM , Bradley EF
Published: November 2004

An account is given of measurements of temperature and humidity at a number of positions and heights within a tobacco crop during a 4 day period. Measurements of the intensity of sporulation of Peronospora tabacina Adam were made at the same time. It is shown that the capacity of P. tabacina to sporulate is controlled not only by nocturnal humidity but also by day temperature. The observations confirm that Cruickshank's laboratory findings hold in the field. The implications of the observations reported here, together with those of other workers on such factors as the spore dissemination and germination characteristics of P. tabacina, are discussed. It is concluded that the basic information necessary to initiate, on a trial basis, a blue mould forecasting and spray warning service is now available.
Temperature regulation in the new-born lamb. VI. Heat exchanges in lambs in a hot environment
Authors: Alexander G , Williams D
Published: November 2004

At ambient temperatures below about 30°C, respiratory and cutaneous evaporation were constant in normal lambs and lambs without sweat glands. Above 30°C, respiratory water loss increased steeply. Cutaneous water loss also increased, but at a slower rate than respiratory loss and only in the lambs with sweat glands. The efficiency of evaporation in cooling the lamb was close to 100%. The contribution of cutaneous blood flow to facilitation of heat loss in lambs lying down appeared to be low. At low environmental humidity, respiratory evaporation at all rates of normal shallow panting was approximately 4 mg per respiration; but in "second phase" breathing this was increased up to 12 mg per respiration, and total respiratory evaporation was not reduced. Lambs showed no evidence of distress when exposed for 6–12 hr to air temperatures of 40°C and water vapour pressures of' less than I5 mm Hg. Cutaneous loss tended to fall and respiratory loss to increase. Maximum rates of cutaneous and respiratory evaporation were estimated by suppressing evaporation from the skin or respiratory tract at 43°C. These values tended to be higher in crossbred lambs then in Merinos, and Merinos tended to reach maximum "sweating" rates under less severe heat stress than the crossbreds. Homeothermic equilibrium was approached when evaporation from neither site was suppressed, but rectal temperatures increased rapidly when cutaneous evaporation was prevented, and more rapidly still when respiratory evaporation was much reduced. The results also illustrate how a high metabolic rate decreases heat tolerance. These experiments provide good evidence that sheep do sweat, but that respiratory evaporation is quantitatively more important than sweating.
Behaviour of annual species of Medicago introduced into a Medicago minima (L). Bart.–dominant disclimax community
Authors: Andrew WD
Published: November 2004

Of the 11 medics introduced into a disclimax community in which M. minima (L.) Bart. was the dominant species in the herbaceous stratum, the only ones which successfully competed with the naturalized medic were: M. confinis Koch, M. scutellata (L.) Mill., M. tribuloides Desr., and M. turbinata (L.) Willd. The last two species are considered the most suitable for widespread testing on well-drained black soils in northern New South Wales.
The measurement of total body water in the sheep
Authors: Till AR , Downes AM
Published: November 2004

After intravenous injections of tritiated water (TOH) were given to sheep, about 5 hr was required for the dose to equilibrate with the total body water (TBW). A standard procedure for estimating the TBW of sheep was adopted, in which blood samples were taken 6 and 7 hr after an intravenous injection of tritiated water. The specific activity of the water from the two samples was measured and the mean value used for the calculation of TBW. As a result of a study of the errors in this method, it was concluded that the value obtained for the TBW is about 2% of the body weight higher than the true value, and has an error of about ±3%. The estimate of the errors was based on direct measurements of the losses of TOH from the animal, and on measuring the rate of fall in specific activity of the TBW. This specific activity fell exponentially with time, with turnover half-times ranging from 3.5 to 16.3 days for sheep housed indoors.
Soil as a factor in the incidence of Peronospora tabacina Adam on tobacco
Authors: Hill AV
Published: November 2004

(1) Plants of a flue-cured variety of tobacco (cv. Virginia Gold) were grown on several soils and subjected to attack by P. tabacina. (2) Leaves of plants grown in soils high in organic matter were large, soft, and succulent and retained the juvenile phase of susceptibility to attack by P. tabacina. Leaves with similar characteristics were not produced following addition of nitrogen to soils low in organic matter. (3) Severity of disease increased during the period of delayed leaf maturity caused by addition to the soil of nitrogen in excess of that required by flue-cured tobacco plants. (4) Soils high in organic matter or in added nitrogen are unsuitable for the growth of flue-cured tobacco, and plants grown in the former are more susceptible to P. tabacina than those grown on the latter. Under field conditions tobacco plants grown on pasture land or on other soils that arc also high in organic matter arc very susceptible to P. tabacina and can be the source of infection for crops grown in a wide area.
Oestrus and ovulation following administration of placental gonadotrophins to Merino ewes
Authors: Lamond DR
Published: November 2004

Following progesterone suppression of ovarian cycles, Merino ewes were given a combination of pregnant mare serum gonadotrophin (PMS) and human chorionic gonadotrophin (HCG) 1 or 2 days after the final injection of progesterone. The incidence of oestrus was recorded and the ewes were mated with entire rams. Laparotomy was carried out 2–3 days after oestrus to observe the number of ovulations and the follicular changes. The ewes were killed 5–6 weeks after treatment and conceptions noted. In non-pregnant ewes the incidence of cystic hyperplasia of the endometrium was recorded. The results may be summarized as follows:(a) Oestrus was inhibited in a high proportion of ewes receiving doses of 540 or 1620 i.u. of HCG. This was independent of the dose of PMS. (b) The number of large follicles was greatest at high doses of HCG. (c) In ewes receiving high doses of HCG, oestrus, if it occurred, was associated with large follicles. (d) Less than 10% of ewes conceived. (e) Endometrial cysts were present in a high proportion of ewes. It is suggested that HCG has a dual effect on ovarian function, depending on dose and the time of injection in relation to stage of follicular growth.
The physiological assessment of the nutrient status of plants. I. Preliminary experiments with phosphorus
Authors: Bouma D , Dowling EJ
Published: November 2004

Subterranean clover plants of different phosphorus status, obtained from pastures or raised in the glass-house, were transferred to nutrient solutions. These included a complete solution, and others each lacking a different element. Subsequent response patterns were defined by leaf area changes. Plants raised at low phosphorus levels showed considerably smaller increases in leaf area in the solutions without phosphorus than in the other solutions. These differences were discernible as early as 2 days after transfer. There was little difference between the control treatments and treatments omitting elements other than phosphorus. Plants raised at a more adequate phosphorus level did not show differences between treatments till much later. The results are discussed, and their use as a basis for a simple method of determining the nutrient status of plants is indicated.
Aphid trapping in Victoria. I. The seasonal occurrence of aphids in three localities and a comparision of two trapping methods
Authors: O'Loughlin GT
Published: November 2004

Information about the seasonal occurrence and peaks of activity of winged aphid species was obtained by trapping during a period of 15 months at three locations within 45 miles of Melbourne. Most species were caught in greatest numbers during either the spring or the autumn. Species such as Myzus persicae (Sulz.) and Brevicoryne brassicae (L.) were caught throughout the year. Cavariella aegopodii (Scop.) was trapped only in cool weather, while Aploneura lentisci (Pass.) was caught only in warm weather. Water-filled yellow trays were very efficient for trapping many species, but a wind-vane sticky trap caught more of some species, including the grass-feeding aphids, than did the yellow tray.
The effect of diet on the secretion of parotid saliva by sheep. II. Variation in the rate of salivary secretion
Authors: Wilson AD
Published: November 2004

The rates of parotid salivation of two sheep were recorded during periods of resting (when not eating or ruminating), eating, and ruminating. Diets differing in both quality and quantity were offered to the sheep, and continuous recordings of the salivation rates of each sheep were made for 24 hr during each dietary period. The mean rate of secretion during rest was lowest at the beginning of a rest period and increased gradually to a peak at the end of the rest period. The mean secretion rate at rest was lowest during the rest period following a meal, and increased gradually to reach a peak during the rest period before the next meal. The secretion rat e during rest was increased by partially evacuating the rumen, and decreased by introducing fluids into the rumen. The mean secretion rates during rest and rumination were higher when the sheep were fed ground hay than when they were fed long hay. The mean secretion rate during rest was increased when the food intake was increased.
The role of the leaves in the accumulation of nitrogen by wheat during ear development
Authors: Neales TF , Anderson MJ , Wardlaw IF
Published: November 2004

When wheat plants were deprived of nitrogen in the rooting medium at anthesis there was a small, but significant, increase in the nitrogen content of the grain at maturity. It was shown that there was a greater migration of nitrogen from the leaves and stem to the ear in plants deprived of nitrogen than in those plants supplied with nitrogen throughout ear development. In an examination of the effects on grain nitrogen content of leaf removal at anthesis, it was shown that this treatment reduces the uptake of nitrogen into the culm and the nitrogen content of the grain at maturity. Ear shading treatments significantly reduced the total nitrogen content of the grain in one experiment. Ear shading also decreased the amino nitrogen, and increased the nitrate nitrogen, content of the ear. Variation of the grain dry weight per ear, induced by shading, by defoliation treatments, or by differences in variety, were positively correlated with grain nitrogen content. Either the movement of dry matter and nitrogen into the ear are interdependent, or they are both promoted by some external factor, such as rate of growth of the ear. The possible importance of the leaves of the wheat plant in promoting the uptake of nitrogen into the culm and in supplying nitrogen to the grain is discussed.
Genetic control of strain-specific ineffective nodulation in Trifolium subterraneum L.
Authors: Gibson AH
Published: November 2004

The nodulation response of the Trifolium subterraneum variety Northam First Early with a range of strains of root nodule bacteria has been investigated. An ineffective response was found with the normally effective bacterial strain NA30. Within F2 populations of crosses between Northam First Early and each of six other varieties of T. subterraneum, the response to inoculation with strain NA30 varied from fully ineffective through intermediate effectiveness to fully effective. The proportion of ineffectively noddated plants in these F, populations was also influenced by the non- Northam First Early parent variety. Differences in response among individual plants within the F, populations were probably due to the segregation of a single major gene and a number of modifying genes. Of 10 other strains examined, one strain showed a similar pattern of response to that obtained with NA30, while a second strain exhibited host x strain specific ineffectiveness of a different type.