bluuebunny/crossref_metadata_2025 huggingface dataset:
Annual reproductive rythm in Merino sheep related to the choice of a mating time at Trangie, Central Western New South Wales
Authors: Dun RB , Ahmed W , Morrant AJ
Published: November 2004

The ovaries from slaughtered Peppin Merino ewes were examined at Trangie for a 12 month period commencing in April 1954. A seasonal rhythm was demonstrated for the percentage of ewes ovulating and for the percentage of multiple ovulations. The seasonal peak was in March–April, with a trough in November–December. Data were compared from a series of autumn and spring matings over the years 1953–1959 using genetically comparable flocks of similar age distribution, mated by identical methods. The overall incidence of oestrus was significantly higher in the first 3 weeks of mating (artificial insemination) in the autumn. The patterns of incidence of oestrus also differed, oestrus being much higher at the commencement of mating in the autumn. Differences between years in the incidence of oestrus were more pronounced in the spring, low incidence being correlated with poor nutrition. In only one mating — spring of 1954, a drought year — was the incidence of oestrus low initially, with a sharp rise commencing at 14 days. The conception rate for autumn-mated ewes was 10 percent. higher than for spring-mated ewes. Little difference was observed in the number and motility of sperm used at the seasonal matings. Lambing percentages strongly favoured the autumn mating: 15 percent. more wet ewes, 25 per cent. more twins mothered, 37 per cent. more lambs mothered, and 33 per cent. more lambs weaned. There was little difference between seasons in ewe deaths prior to and during lambing, or in deaths of lambs between mothering and weaning. The relative importance of the factors causing the 37 per cent. more lambs mothered in the autumn mating was as follows: incidence of oestrus, 11 per cent.; pattern of oestrus, 5 per cent.; incidence of multiple ovulation, 57 per cent.; conception rate, 27 per cent. The importance of the conception rate could be largely an associated effect of the higher autumn incidence of multiple ovulation. The weaning weight of lambs tended to be slightly higher for autumn matings, although there was great variation between years, both in the size and in the sign of differences. These differences had almost disappeared by 17 months of age. The choice of a mating time in central western New South Wales is discussed relative to these findings.
Methods of analysis and the influence of fleece characters on unit area wool production of Romney lambs
Authors: Henderson AE , Hayman BI
Published: November 2004

Investigation has been made of the influence of fibre number per unit area (N), cross-sectional area of fibre (A), and fibre length (L), on wool production per unit area of skin (W). The influence of the compound characters fibre volume (V) and proportion of skin area occupied by fibre (0) has also been considered. Methods are given whereby the significance of the variation associated with any one of these interacting components can be assessed. Data from four groups of lambs were analysed, each group having been subjected to a different nutritional regime. Slightly more than three-quarters of the variation induced in W by these treatments was due to variation in L, with N and A having negligible effects. No evidence was found that the relative influence of the components changed with change in level of production. Differences in W between lambs on the same nutritional level were influenced almost equally by variation in N and L, with A again having a negligible effect. Of the variation in W between positions on lambs, approximately 50 per cent. was accounted for by variation in N, 40 per cent. by variation in A, and 10 per cent. by variation in L. Variation of the compound character O accounted for nearly 90 per cent. of the variation in W over the body.
The effects of nicotinic acid in experimental carbon tetrachloride poisoning of sheep
Authors: Gallagher CH
Published: November 2004

A course of three daily intraperitoneal injections of 2 g nicotinic acid, a precursor of pyridine nucleotides, was found to afford considerable protection to sheep against specific liver damage and dysfunction following a dosage of 50 ml CCl4 given into the rumen on the same day as the third injection. The protection was apparent in the histological picture, respiratory activity, and the concentration of acid-soluble materials which absorb light at 260 mµ. One dose of 2 g nicotinic acid injected intraperitoneally, or given by stomach tube into the rumen, gave a significant measure of protection against the loss from liver homogenates subsequent to a dose of CCl4 of acid-extractable materials which absorb light at 260 mµ. Some protection was given by one dose administered by either of these routes at the same time as CCl4, but the greatest protection was given by the administration of the nicotinic acid a day earlier. Under the conditions of the experiments sheep tolerated very large doses of CCl4, so that it was not possible to assess the prophylactic value of nicotinic acid against lethal doses of CCl4. The results are discussed in relation to the field problem of deaths among sheep treated with CCl4.
The effect of the quantity and quality of pasture available to sheep on their grazing behaviour
Authors: Arnold GW
Published: November 2004

During the spring of 1969 four originally similar plots of a Phalaris tuberosa subterranean clover pasture were grazed at different stocking levels to produce a range in levels of pasture availability. The plots were subsequently grazed at 12, 16, 20, and 24 sheep per acre in a 4 x 4 Latin square design. On these pastures, as the amount of pasture available decreased, there was a significant increase both in the nitrogen content of available material and in the diet selected by oesophageal-fistulated sheep grazing them. These differences in the quantity and quality of available pasture produced significant changes in the grazing behaviour of sheep. Grazing time showed a linear increase with decreasing pasture availability, but the rate of increase in grazing time was insufficient to maintain liveweight. Ruminating time was significantly reduced as pasture availability declined. There were considerable differences between sheep in their ability to increase their grazing times as pasture availability decreased. These differences could be of considerable practical implication.
The influence of dissolved gypsum on pasture establishment on irrigated sodic clays
Authors: Davidson JL , Quirk JP
Published: November 2004

The heavy grey and brown soils of the Riverine plain have been considered to have a low irrigation potential primarily because of the difficulty of pasture establishment. A series of experiments has indicated that satisfactory establishment can be achieved by the application of gypsum. For increased emergence the most efficient method of applying gypsum was to dissolve it in the first irrigation water. The reason for adding gypsum in solution was to obtain flocculation rather than calcium saturation of the soil colloids. This represents a novel approach to the reclamation of sodic soils and is clearly different from the procedure used in the United States, where smaller quantities of gypsum are added to the irrigation water to adjust the sodium : calcium ratio of the water. The treatment with gypsum leads to a more friable soil surface, increases the rate of water entry, and results in increased yields per plant.
Puberty in the Merino ewe with special reference to the influence of season of birth upon its occurrence
Authors: Watson RH , Gamble LC
Published: November 2004

Observations were made on the occurrence of mating and lambing in Merino ewes of three groups born in the spring, summer, and winter respectively. The lambs ware weaned at 13½–14½ weeks of age, and joined with rams within the following 2 weeks, some with fertile rams, others with vasectomized rams. Thereafter they ran with rams continuously or until lambing occurred. With few exceptions the first oestrus occurred between late November and May (summer and autumn), and the first conception between November and June. Of the ewes born in the spring, summer, and winter, 78, 100, and 95% respectively exhibited oestrus, and 63, 95, and 80% respectively conceived during the first spring, summer, and autumn following birth. All of the remainder experienced oestrus and all except one conceived during the same period in the following year. Both the age and the body weight of the ewes when oestrus and when conception first occurred varied widely. Both were least in the animals born in the spring and greatest in the animals born in the summer. The sexual season was shorter in the young ewes than it was in mature ewes. Further, the first sexual season of the youngest ewes at the time (those born in the spring) was only one-third of the length of the second sexual season or of the first sexual season of the ewes of the other two groups. There was little delay between the first opportunity to conceive and conception. However, among the ewes which mated youngest the proportion which lambed was lower than that in the other young ewes, which in turn was lower than in mature ewes. In addition, the gestation period in at least half of the ewes which lambed 3 youngest was substantially longer than it was in all except a very few of the other ewes
The modification of climate near the ground by irrigation for pastures on the Riverine plain
Authors: de Vries DA , Birch JW
Published: November 2004

Methods are described and results reported of meteorological observations made during the irrigation seasons 1936–57 and 1957–58 at three stations in the Nanneella irrigation area (dimensions approximately 6 by 7 km²) and on a dry-land station nearby. The former stations are situated on irrigated pastures, whilst the latter is on a dry-land pasture. Irrigation gives rise to a decrease of air and soil temperatures and an increase of atmospheric humidity- near the surface of the earth. The magnitudes of these effects depend inter alia on the irrigation rate and the distance down wind in the irrigated area. In summer at an irrigation rate of approximately 0.3 cm/day the observed differences between the dry-land station and a station in the centre of the irrigation area amounted to: 1–2°C for air temperature at screen height (125 cm); approximately 10°C for soil temperatures (at depths of 5 and 30 cm); 5–10% for relative humidity at screen height; 0.5–1.5 mm Hg for vapour pressure at screen height. The differences quoted are for average values of the observed quantities taken over a period of 4 weeks. The observations are presented in more detail in graphical form.
Some observations on the nature of organic sulphur compounds in soil
Authors: Freney JR
Published: November 2004

The chemical reduction of soils showing a range of properties with a mixture containing hydriodic acid resulted in liberation of hydrogen sulphide equivalent. to, on the average, 59% of the total sulphur. Inorganic sulphur compounds, which are included in this reducible sulphur fraction, accounted for only 7 % of the total sulphur. The remaining portion of the reducible sulphur appeared to be organic because it as strongly correlated with various measurements of the soil organic matter, and because it could only he extracted with reagents known to extract organic matter from soil. Most of this reducible sulphur occurred in the fulvic acid fraction of the extracts, and it could be hydrolysed to inorganic sulphate. Some evidence has been obtained to suggest that there is considerable sulphate in soils covalently bound to certain compounds of the organic matter.
Efficiency of conversion of food to wool. 2. Comparison of the efficiency of the same Merino ewes on two different rations
Authors: Dolling CHS , Moore RW
Published: November 2004

During a 12-meek period a group of nine medium Peppin maiden ewes was fed ad libitum a ration of lucerne chaff while a similar group was fed ad libitium a mixture of oaten chaff and lucerne chaff in the ratio of 10 to 1. During a second 12-week period the rations of these two groups were reversed. Food consumed by each sheep was weighed and protein consumption obtained from food and residue analyses. Clean wool production for each sheep was recorded in each period. Two measures of efficiency used were the ratios of clean wool to air-dry food consumed (W/F) and to crude protein consumed (W/P). For W/F the interaction between sheep and ration or period was significantly greater than variation between subperiods (P < 0.001), but the between-sheep variance was in its turn much greater than the interaction (P<0.O01), giving a repeatability of 0.76 for efficiency measures on the same sheep. For W/P also the interaction was significant (P <0.05), the repeatability estimate being 0.74. The correlation coefficient between measures for the same sheep on the two rations were 0.83 for W/F and 0.84 for W/P. It is concluded that, although some significant interaction between sheep and ration was demonstrated, it was not of great importance, and, consequently, selection of sheep on efficiency with one ration of the type described u-auld also hold, with small loss of accuracy, with a second such ration.
Observations on hair growth and shedding in cattle
Authors: Hayman RH , Nay T
Published: November 2004

On three occasions during the period l91S-1956 field observations were made on coat shedding in B. indicus, B. taurus, and B. indicus x B. taurus cattle, and hair and skin samples taken. Measurements of hair length, diameter, and weight per unit area of skin were made, and stages of hair growth within the follicle observed. On two occasions hair data included measurements of length and diameter on individual hairs. Two shedding periods were observed. in spring and in autumn. Approximately 4 months was required for the complete change from m-inter to summer coat, the change in appearance being dramatic. Less time was required for autumn shedding and there was a less dramatic change in the appearance of the coat. Histological data from skin samples supported these observations and showed that during shedding almost all mature hairs were lost from the skin follicles. All types of cattle had characteristically short, light summer coats and long, heavy winter coats. No difference in hair diameter was observed between summer and winter coats in B. taurus, but in B. indicus hair diameter was much greater in the summer coat. In all seasons 01 the year B. indicus had the shorter and lighter coats. The minter coat in long-coated B. tauws did not appear to hare an undercoat, whereas short-coated B. taurus and B, indicus had distinct undercoats. In B. indicus x B. taurus F1 crossbreds coats were as'short in summer as those of B. indicus, and as long in winter as those of B. taurus. Differences between species in shedding, and in coat characteristics at different seasons of the year, may be of ecological importance.
Studies on the efficiency of pollination of lucerne in South Australia.
Authors: Doull KM
Published: November 2004

A method of assessing the efficiency of pollination of lucerne (Medicago sativa L.) has been developed. A number of samples, each consisting of 200 racemes, is taken, and the number of flowers produced and pods set on each raceme are tabulated. The efficiency of pollination is determined both by calculation of the proportion of flowers which produce pods, and by calculating the frequency distribution of numbers of flowers and pods per raceme. Hunter River lucerne in a cage without bees produced pods from only 10.5% of the flowers, as compared with 35.3% in the open field and 56.6% in a cage with bees. It is concluded that this variety of lucerne, in common with other varieties, requires to be pollinated by insects before it can produce commercial yields of seed.
Symbiotic characteristics of Rhizobium meliloti from the brown acid soils of the Macquarie region of New South Wales.
Authors: Brockwell J , Hely FW
Published: November 2004

Thirty-three isolates of Rhizobim meliloti were obtained from the brown acid soils of the Macquarie region of New South Wales and their symbiotic behaviour in association with 11 species of Merlicago and three species of Melilotus was investigated in the laboratory. In respect of nodule formation, there were two distinct types of Rhizobiurn and the hosts formed three groups. In respect of nitrogen fixation there were six strain types and seven host, groupings. These host and bacterial groups could be arranged in a series. Several of the strains of rhizobia, and one in particular, were found to fix a high level of nitrogen with a number of hosts, but, except for ;Medicago denticulata Willd. and Melilotus indica (L.) All. which behaved identically in all features of the symbiosis studied, no definit'e groupings on this criterion were apparent in either hosts or bacteria. The possible application of the results to the selection of strains of' Rhizobium meliloti suitable for seed inoculation is discussed.
Competition between two varieites of subterranean clover (Trifolium subterraneum L.) as related to the proportions of seed sown
Authors: Black JN
Published: November 2004

The Yarloop and Tallaroolr varieties of subterranean clover (Trifolium subterraneum L.) xvere grown in swards in six mixtures, varying from 100% Yarloop/0%, Tallarook to 0% Yarloop/100% Tallarook, to find out whether the suppression of Tallarook by Yarloop consequent upon the greater petiole elongation of yarloop would still occur when only a few Yarloop plants were present. The swards were grown in large seed boxes and were sampled on four occasions during vegetative growth. Leaf areas for each 2 cm layer of the swards were determined separately for the two strains, and light intensities at each layer were measured at each sampling occasion. It was shown that Yarloop plants suppressed Tallarook in all mixtures. The relative amounts of light energy available to the two strains in the mixed swards left no doubt that the suppression of Tallarook was the result of shading by the taller-growing Yarloop plants.
Some aspects of selenium metabolism in sheep
Authors: Cousins FB , Cairney IM
Published: November 2004

The occurrence and relationship of various complaints in lambs and hoggets, preventable by selenium prophylaxis, are reviewed. The excretion and tissue retention of selenium by animals on normal feeds and on oral dosing with sodium selenite are given. Faecal excretion of selenium, even on low levels of intake, is high and it is suggested that reduction of dietary selenium to a non-available form occurs in the rumen. In all animals investigated, the kidney showed the highest selenium levels and was the organ most influenced by selenium absorption. The kidney selenium levels provide an adequate index of the animal's selenium status. Tissue selenium levels from healthy, white muscle, and ill-thrifty lambs and hoggets were investigated. There is evidence that the occurrence of muscular dystrophy in lambs, but not necessarily in hoggets, is related to lowered tissue levels of selenium. Findings with respect to ill-thrift and selenium tissue levels were equivocal. The above work is considered together with published information on the nutritional causes of muscular dystrophy in sheep.
Some effects of carbon tetrachloride intoxication on liver and kidney function in sheep.
Authors: Setchell BP
Published: November 2004

Observations have been made of the effect of toxic doses of carbon tetrachloride per os on bromsulphthalein clearance, p-aminohippurate synthesis from p-aminobenzoate, plasma concentrations of bilirubin, glutamate oxalacetate and glutamate pyruvate transaminase, protein fractions, creatinine, urea, creatine, "guanidine", phenols, potassium, sodium, calcium, lipid fractions and amino acids, prothrombin time, blood ammonia concentrations, urine volume, specific gravity, osmolarity, protein concentration, and p-aminohippurate and creahine clearances. It was found that a marked degree of both kidney and liver dysfunction followed administration of carbon tetrachloride. There was a similar degree of liver dysfunction in those sheep that died and in those that survived. Kidney dysfunction was much more severe in those animals that died. The kidney dysfunction preceded the symptoms in all cases.
Variations in the skin and skin-fold thickness of beef cattle.
Authors: Tulloh NM
Published: November 2004

A series of successive skin-fold measurements were made on the midside area of Hereford, Angus, and Shorthorn steers of the same age reared together from birth until slaughter. Biopsy skin samples were taken from the midside area of these steers just before slaughter. An investigation of various sites of measurement showed that the skin over the midside area was relatively uniform in thickness. A Harpenden skin-fold calliper was used for skin-fold measurements. They were obtained without using a local anaesthetic, because it was found that any relaxation of the skin which an anaesthetic may produce was not detected with this instrument. The thickness of biopsy skin samples was measured with a Mercer dial micrometer No. 131. The correlation coefficient between skin and skin-fold measurements was 0.82. High correlations of skin and skin-fold thickness with fresh and dry weights of skin samples were obtained. A marked association of skin-fold thickness with age and with liveweight was found up to the age of 26 months. It appears that these changes in skin-fold thickness wese more closely related to liveweight than to age. Evidence is presented which indicates that there is probably a sex difference in skin-fold thickness, cows having thinner skins than steers. A significant correlation coefficient (r = 0.50) was found between the skin-fold thickness of steers and of their dams. Seasonal fluctuations in skin-fold thickness were obtained, which were independent of changes in liveweight. A thicker skin-fold measurement was obtained on areas which had been clipped regularly compared with areas which had not been previously clipped. Breed differences in skin and skin-fold thickness were obtained. The mean skin thickness for steers aged 26 months was: Hereford, 9.45 mm � S.E. 0.20; Angus, 8.04 mm � S.E. 0.16; Shorthorn, 6.85 mm � S.E. 0.33. In a series of single observations just before slaughter, no relation was found between skin thickness and liveweight. Therefore it is unlikely that skin thickness is a useful criterion for selecting high growth rate animals in this environment.
Tomato yellow top virus: Its distribution, characteristics and transmission by the aphid Macrosiphum euphorbiae (Thom.)
Authors: Braithwaite BM , Blake CD
Published: November 2004

A study of the virus disease of tomato plants known as tomato yellow top is reported. The spread of the virus in eastern Australia from the Sydney metropolitan area in the period 1952–1960 is summarized and the current geographic distribution of the disease outlined. Symptoms of the disease on tomato plants, including the effect of plant vigour and age, are described. Symptoms on Physalis floridana are also described. Attempts to transmit the virus by mechanical means were unsuccessful, and no seed transmission was observed. The virus was transmitted by grafting and by the potato aphid, Macrosiphum euphorbiae, apterae of which appear to be the principal vector. Under experimental conditions the aphid required a minimum feeding period of 90 min to acquire the virus and 30 min to inoculate healthy seedlings. Optimal transmission of the virus was attained with an acquisition feed of 8 hr and an inoculation feed of 3 hr. Inoculated plants developed symptoms after 18–21 days. Infective aphids were able to cause transmission after moulting, and serially for 10 days without further feeding on infected plants. The virus was thus found to be of the "persistent" type. A weed, Solanum nigrum, is susceptible to tomato yellow top virus, and it is suggested that it is a source of infection for crops of tomatoes.
The development of parotid salivation in the lamb
Authors: Wilson AD , Tribe DE
Published: November 2004

The development of the parotid gland was studied in lambs reared under the following three dietary conditions: (a) lambs freely grazed with their ewes; (b) lambs hand-reared on milk and hay; (c) lambs hand-reared on milk alone. Weekly measurements were made of the saliva flowing from the cannulated parotids of two anaesthetized lambs from each group, during reflex and electrical stimulation of their glands. The fresh weights of the parotid and submaxillary glands and of the four stomachs were also recorded. Before 4 weeks of age, all the parotid glands were physiologically immature, secreting only 0.1–0.2 g saliva/g parotid tissue/min. The parotids of the grazing lambs developed rapidly from 4 to 6 weeks of age and reached adult capacity of 0.50–0.65 g/g/min between 7 and 10 weeks of age. The parotids of the lambs receiving millr and hay developed more slowly than the grazing lambs, while the parotids of the lambs receiving milk only scarcely developed at all. The histological examination of these glands showed that the parotids of the 2-week-old lambs were immature. Differentiation in the grazing group occurred at 4–6 weeks of age, while no differentiation occurred in the lambs fed milk only. The rate of flow of parotid saliva from all lambs was significantly correlated with the fresh weight of rumen tissue. The parotid gland increased in weight in relation to the rumen weight and not to the body weight.
The absorption and movement of 32P-labelled systemic insecticides in the grape vine (Vitis vinifera L.)
Authors: Coombe BG
Published: November 2004

Three systemic insecticides, schradan, dimefox, and demeton-S, containing 32P , were applied by different methods at different times to study their behaviour in grape vines, particularly their accumulation in roots. Foliage sprays, "capsule" treatment, and banding of the trunk (with various supplementary treatments such as cincturing, abrasion, and twig removal) gave low levels of insecticide in the roots; some of these treatments gave high levels in the leaves. Watering in November and February, and shoot injection in April, resulted in concentrations of 17 mg schradan per kg in roots 15 days after treatment. Schradan accumulated in vines at slower rates, decomposed less, and was less affected by time of treatment than has been reported in other plant species. Dimefox was absorbed in amounts about equal to schradan but it decomposed rapidly, so that low levels of insecticide were found in the roots. Dimefox was phytotoxic when applied in a trunk band. Demeton-S levels were low in roots owing to its ready transport to leaves. The evidence suggests that it does not move easily in phloem.
Studies on the artificial insemination of Merino sheep. II. The effects of semen diluents and storage on lambing performance
Authors: Salamon S , Robinson TJ
Published: November 2004

(1) Results of large-scale insemination trials conducted in the autumn of 1960 and involving 1955 Merino ewes in two flocks of mixed ages are presented. (2) Three factorial tests were conducted. The effects on returns to service and lambing performance of semen diluents and rams were studied with fresh semen (test 1, 240 ewes) and semen cooled, transported, and used 3–5 hr after collection (test 2, 300 ewes). Test 3 (320 ewes) compared the effects of duration of storage (0, 24, 48, 72 hr), diluents (heated cow milk 1 : 2, egg yolk-glucose-citrate (E.Y.G.C.) 1 : 2), antibiotic additive (nil, penicillin 1000 i.u./ml), and rams (two). (3) Overall returns to service and lambing results to insemination over one or two cycles were: test 1—fresh semen, 28.2,68.1, 77.7% ; test 2—cooled transported semen, 31.2, 63.5, 72.0%. There were no effects of diluents or of rams on results for these tests. (4) There was a linear regression of percentage fertility on duration of storage (test 3, pooled data for all diluents and rams) with the following formula: y = 61.0 – 14.0x, where y = percentage of ewes lambing to a single insemination, and x = duration of storage in days. (5) There was a significant ram difference (P < 0.05) but it did not affect the slope of the regression. (6) E.Y.G.C. was more effective than cow milk (P < 0.01) and there was a significant interaction between diluent and antibiotic additive (P < 0.05). Penicillin increased the relative effectiveness of cow milk but not of E.Y.G.C. (7) There was a significant interaction between duration of storage and antibiotic ( P < 0.05). Addition of penicillin appeared to lessen the slope of the regression. (8) It is concluded that the maximum duration of storage of ram semen with present diluents is 24 hr, and even this will probably result in a loss of fertilizing capacity of about 15%.
Interaction of nutrition and air temperature with water metabolism of Merino wethers shorn in winter
Authors: Morris RJH , Howard B , Macfarlane WV
Published: November 2004

p>Field observations were made on Peppin Merino wethers maintained at 6 and 9 per acre throughout the year on improved pasture in Canberra. Estimations of water distribution with the use of tritium, thiocyanate, and T1824 indicated that stocking rate in autumn had little effect on body composition or water intake. Before shearing in July, however, the 9-per-acre sheep had lost 16% more weight than those at 6 per acre, although body water distribution was similar in the two groups. After shearing, both groups shivered continuously for 3 weeks. The 9-per-acre animals had lower rectal and higher skin temperatures than the 6-per-acre sheep. Skin and rectal temperatures were reciprocal to wind velocity. Both groups lost over 3 kg weight (5.9 and 8.4% of body weight) in 2 weeks, but in the 9-per-acre sheep, body water increased by 8.7% while in the 6-per-acre group 4.4% of body water was lost. The 9-per-acre sheep lost 30.7% of tissue solids, compared with 7.5% in the better-fed animals. It is likely that cellular water content increased in the 9-per-acre animals. An increase in density of stocking from 6 to 9 per acre cost three times as much tissue and fat during the cold period, while this loss of solids was partly obscured by replacement of tissues with water.
The reactions of unshorn and shorn sheep to hot wet and hot dry atmospheres
Authors: Klemm GH
Published: November 2004

Three Merino sheep with fleeces 7–8 cm in length were exposed to a series of hot wet and hot dry atmospheres. Their reactions to each of the environments were observed by recording rectal temperature and respiratory rate at hourly intervals during exposure. At the completion of a series the sheep were shorn to about 0.5 cm length of wool and again subjected to the same series of atmospheres. Hot wet atmospheres were better tolerated by the shorn sheep, whereas the unshorn animals reacted to a lesser extent under hot dry conditions. These observations are in keeping with the data obtained by Lee (1950). An attempt has been made to explain these findings in terms of some physico-chemical properties of wool.
The role of solar energy in the drying of vine fruit
Authors: Wilson BW
Published: November 2004

In Australia grapes are dried almost exclusively by natural energy on tiered racks usually sheltered by an iron roof. Under these conditions it was shown that there is a close relationship between direct solar radiation and rate of drying. Wavelengths of 0.7 to 0.9 µ, which are abundant in sunlight, penetrated grape skins, particularly after (cold) dipping treatments, and temperatures within the grapes in excess of 8°C above air temperatures were frequently recorded. The quantity of water evaporated from grapes on a weighed drying rack approximated closely to estimates based on simultaneous measurements of solar radiation. The efficiency of tiered drying racks was superior to that of two types of low cost air driers in which solar energy absorbers were used.
Pre-natal growth in Romney X Southdown cross and Austrailan Merino sheep. II. Carcass conformation in the two breed groups
Authors: Stephenson SK
Published: November 2004

The carcass conformation of the sheep foetus has been studied during the period from 50 to 140 days after conception by taking a series of linear measurements over the surface of the body. The mean lengths and the rates of increase in the length of such measurements, with increases in foetal age, are compared between the Romney southdown cross and the Australian Merino breed groups, and also between sexes within each breed group. Although these differences have been analysed on an age basis, the relationship between age and total body length is similar in the two breeds and therefore the same breed effects should also be found if total body length is taken as the primary growth measurement. Further, the rates of increase in length of the measurements of the parts of the body, relative to the rate of increase in total body length measured as curved crown-rump, have been estimated, foetal age being used as the independent variable rather than total body length. The results show that ram foetuses have larger head and neck measurements in both breed groups during early foetal life. The major difference between breeds is the greater width and circumference of the neck and trunk in the Romney x Southdown cross. In addition, the width of the head and the length of the nose are higher in the Romney x Southdown cross, while the humerus head is displaced forward and downward in this breed group, giving a relatively longer and deeper trunk and a shorter neck than the Merino. The allometric growth gradients are broadly similar to those for other mammals, and also to measurements obtained by other workers for the sheep during pre-natal life. No conclusive evidence was obtained to show whether or to what extent the breed differences resulted from alterations to the allometric growth rates or to changes in the dimensions of the parts during morphogenesis. The results do indicate, however, that the alterations to early-developing parts such as the head may result partly or wholly from changes in the initial dimensions, whereas changed in the allometric growth rates appear to produce the differences in the width and circumference of the neck and trunk. The latter effect may also be determined to a relatively greater extent by maternal influences.
Parasitic gastro-enteritis of cattle: Seasonal fluctuations in populations of strongyle larvae on a calf pasture and their significance in infection of the grazing animal
Authors: Durie PH
Published: November 2004

Fluctuations in populations of infective larvae of cattle strongyles on a naturally grazed calf pasture were studied for 2 years. Susceptible calves were introduced to the pasture each month to determine how host infection was influenced by the degree of pasture contamination as measured by the number of larvae recovered per pound of pasture. The most numerous larvae recovered at all seasons belonged to the Cooperia spp. group. Larvae of Trichostronqylus axei were abundant throughout the winter to early summer, but scarce during midsummer and autumn. Larvae of Haemonchus placei were most abundant during the late summer and winter, and those of Oesophagostomum radiatum occurred in relatively small numbers at all times. Gross peaks of abundance occurred during the summer and midwinter, when the rainfall was higher than at other periods of the year. Although greater numbers of larvae per pound of pasture were recovered during the winter than during the summer, host infections were higher during the summer. This inverse relationship between the number of larvae and host infection is believed to be a result of a greater intake of pasture during the summer. An assessment of the degree to which a pasture may be dangerous therefore involves consideration not only of the number of larvae present, but also of the state of the pasture. Estimates of the daily intake of larvae by susceptible animals, allowed to graze for a restricted period and then examined at necropsy, ranged between 19 and 31 655 larvae.
Frequencies of annual species of Medicago on subgroups of the grey and brown soils of heavy texture of the Macquarie Region of New South Wales
Authors: Hely FW
Published: November 2004

Four broad subgroups were recognized in the grey and brown soils of heavy texture in the Macquarie region of central New South Wales, and five annual species of Medicago (medics) were found occurring naturally on these soils, but with different frequencies on various subgroups. Some medic material was found in all quadrats on three subgroups and in nearly all fields and the majority of quadrats on the soils of the other. Medicago denticulata Willd. dominated one subgroup, occurring in all quadrats of all fields sampled. This species also occurred in approximately three quarters of the fields and half the quadrats sampled on two other subgroups, and was found in half the fields and a quarter of the quadrats of the fourth subgroup. Medicago minima (L.) Bart. showed a contrary preference, occurring with only slight frequency on the first, and with greatest frequency on the fourth subgroup. Medicago laciniata (L.) Mill. and Medicago tribuloides Desr. were of an intermediate nature and occurred principally on soils of the second and third subgroups. Medicago praecox DC. was found only on soils of the fourth subgroup and at low frequency. The nature of associations between medics showed that differences existed between subgroups of soils with respect to the preference of one species or another for them.
The inheritance of DDT-resistance in the cattle tick, Boophilus microplus
Authors: Stone BF
Published: November 2004

Adults of a DDT-resistant strain of the cattle tick from central Queensland were crossed with adults of a susceptible reference strain, by means of cardboard mating boxes glued to the skins of cattle. F1, backcross, and F2 larvae were tested for resistance to DDT by enclosure of larvae in filter paper packets impregnated with oil solutions of pp'-DDT. F1 and backcross engorged adult females were tested for resistance by injection with oil solutions of pp'-DDT. There was no evidence of departure from a 1 : 1 ratio in the backcrosses or from a 1 : 2 : 1 ratio in the F2, and there was little difference between the compositions of the F1 reciprocal crosses or among the backcrosses derived from them. Therefore DDT resistance in this strain was considered to be due to a single, incompletely recessive, autosomal gene. Engorged nymphs of the resistant strain moulted later in vitro than nymphs of the susceptible strain, and resistant engorged adult females detached from the host later than susceptible engorged adult females. After 13 generations of DDT-free culturing of a multiresistant strain, the percentage of homozygous DDT-resistant ticks in the strain had fallen from a high level to about 55%. This figure remained constant for a further 10 generations.
The inheritance of dieldrin-resistance in the cattle tick, Boophilus microplus
Authors: Stone BF
Published: November 2004

Adults of a dieldrin-resistant straiu of cattle tick from southern Queensland were crossed with adults of a susceptible reference strain, by means of cardboard mating boxes glued to the skins of cattle. The F1 and backcross larvae were tested for resistance by enclosure in filter paper packets impregnated with oil solutions of dieldrin. The corresponding engorged adult females were tested by injection with oil solutions of dieldrin. There was no evidence of significant departure from a 1 : 1 ratio of resistant and susceptible phenotypes in the backcrosses, and there was little difference between the composition of the F1 reciprocal crosses or between the backcrosses derived from them. Dieldrin-resistance in this strain appears to be due to a single, dominant autosomal gene. Dieldrin-resistant ticks in a multiresistant strain from central Queensland steadily declined from 50–60% to an undetectable percentage in a laboratory population bred in the absence of dieldrin for 24 generations.
Studies on the carbohydrate metabolism of sheep. XVIII. The metabolism of glucose, free fatty acids, ketones, and amino acids in late pregnancy and lactation
Authors: Reid RL , Hinks NT
Published: November 2004

The metabolism of glucose, free fatty acids (FFA), ketone bodies, and amino acids in late pregnancy and lactation was studied at three levels of feeding in an experiment designed to measure the increase in nutrient requirements of ewes with advancing pregnancy.The plasma FFA level is a more sensitive criterion of undernutrition during pregnancy than the level of blood glucose or ketones. In ewes on a constant feed intake and in medium body condition approaching late pregnancy, the rate of mobilization of fat reserves necessary to maintain caloric homeostasis, as indicated by plasma FFA level, was closely correlated with total foetal weight in late pregnancy and with the level of milk production in the first month of lactation. However, these ewes were unable to maintain blood glucose levels in the normal range in late pregnancy; severe hypoglycaemia was present in twin-bearing ewes. Caloric homeostasis was best maintained in fat ewes fed ad libitum; variation in blood glucose and FFA levels during late pregnancy and early lactation was minimal, in spite of a marked and variable decline in feed intake in twin-bearing ewes in late pregnancy. Reduction of foetal demand for nutrients may prevent or defer the breakdown of homeostatic meohanisms, but appears to play a minor role in the maintenance of caloric homeostasis in the undernourished pregnant ewe. However, reduction in the level of milk production is a major factor in the undernourished lactating ewe; severe hypoglycaemia and hyperketonaemia are thus prevented. The metabolic effects of high foetal requirements of amino acids are discussed in relation to observed variations in plasma amino acid Level in late pregnancy.
Factors determining the length of the incubation period of Monilinia fructicola (wint.) Honey in fruits of Prunus spp.
Authors: Corbin JB
Published: November 2004

The length of the median incubation period of Monilinia fruticola (Wint.) Honey was determined on fruits of several Prunus species at various maturity, injury, and inoculum levels; the median incubation period being defined as the interval between application of conidia to fruits and the first appearance of sporodochia on 50% of fruits. Results were expressed as the time required for 20% and 50% of fruits to produce sporodochia. The following points were demonstrated: (1) Differences in the median incubation period between varieties for similar inoculum dosage were greatest when fruits were least matured and non-injured. (2) These differences became less apparent as inoculum dosage increased, as fruits matured, and as skin injuries increased. (3) Green fruits could be infected by high inoculum dosages when non-injured and by low inoculum dosages when injured. (4) Ripe fruits could be infected by low inoculum dosages whether non-injured or injured. (5) Free ("precipitated") moisture was necessary for infection. High relative humidity (R.H.) maintained this moisture after application of spore suspensions, thus permitting infection, whilst low R.H. allowed this moisture film to dry out, preventing infection. (6) After infection occurred, the R.H. level did not appear to affect the sporulation intensity.The above results are discussed in relation to the concept of inoculum potential, as defined by Garrett (1956), and to the development of epiphytotics and other aspects of the epidemiology of the brown rot fungus.
The ionic composition of rainwater at Katherine, NT. and its part in the cycling of plant nutrients
Authors: Wetselaar R , Hutton JT
Published: November 2004

Rainwater was collected from individual showers at Katherine, Northern Territory, Australia, during the 1958–59 wet season, and again in 3.4 mm portions of individual showers during the 1959–60 wet season. Strict precautions were taken during rainless periods to prevent particulate material from accumulating in the rain collector. The laboratory examination of the samples included determinations of nitrate, ammonium, sodium, potassium, magnesium, and chloride ions, and of insoluble silica. Soil and plant material samples collected in the surroundings of Katherine were also analysed for a number of elements. In spite of a total annual average rainfall of 925 mm the annual total amount of soluble material in the rainwater was less than 6–7 kg 'ha. The concentration of all ions decreased during the progress of a shower, and from shower to shower, during the progress of the season. Correlation coefficients between the different ions were all positive and generally high. No relation could be detected between the nitrate content in the rainwater and the incidence of lightning. The correlation between chloride content and amount of insoluble silica was high (+ 0.73). It is argued that most of the material in the rainwater is part of a terrestrial cycle and cannot be regarded as a true accession.
Barriers to Dermatopilus dermatonomus infection on the skin of sheep
Authors: Roberts DS
Published: November 2004

In adult Merino sheep, but not in coarser-woolled breeds, the greasy fleece and the film of sebaceous wax on the underlying skin were found to be efficient barriers to infection with Dermatophilus dermatonomus. Severe infection resulted from the application of liquid cultures after the removal of wax with light petroleum. On several non-woolled regions resistance was shown to depend on the thickness and integrity of the stratum corneum. A study was made of the development of the sebaceous film and of its properties. It was shown that the rate of formation of the protective film was not affected by differences in atmospheric temperature, or by the moderate reduction in wax output observed both in pregnant ewes and in wethers given large doses of oestrogen. It was found that variations in the bacteriostatic action and melting point of sebum did not affect the protectiveness of the film or the ability of naturally infected sheep to overcome the disease. Outbreaks of body infection commonly commence in Merinos soon after birth or shearing, and between the ages of about 3 and 12 months. These were shown to be times when the fleece, and the wax film on the skin, provide inadequate protection. Pronounced fluctuations in susceptibility were observed on the face and ears, which are important reservoirs of infection, and were shown to be associated with natural variations in the integrity of the wax film on the face and of the stratum corneum on the ears.
Resistance to subterranean clover stunt virus
Authors: Peak JW , Morley FHW , Grylls NW
Published: November 2004

In glass-house tests of 40 subterranean clover lines showing field resistance, 21 were found to be resistant. These included lines from Portugal, Spain, Morocco, Greece, Tunisia, and Australia. The resistance of the Australian varieties Tallarook and Hill's Small was confirmed. Three further lines from Australia, Hexham Smooth Stem, Hexham Hairy Stem, and Samaria, were also found to be resistant. Bass B, previously classed as resistant, gave variable results. The level of resistance in the F1's from crosses between resistant and susceptible parents equalled that of the resistant parents, which indicated complete dominance of resistance. The F2 values were somewhat higher than those of the mid-parents. Variations among resistant and susceptible parents, and among F2's of susceptible parents, indicated that resistance is not determined solely by a single gene. Modifiers, and probably different major genes, appear to be present. The implications of these results for plant breeding are discussed.