bluuebunny/crossref_metadata_2025 huggingface dataset:
Selective grazing by sheep of two forage species at different stages of growth
Authors: Arnold GW
Published: November 2004

In a series of experiments where the rate of stocking was such that consumption exceeded growth, sheep continuously grazing pastures of lucerne or Phalaris tuberosa exhibited distinct preferences. On both forages sheep continuously selected leaf in preference to stem where this was physically possible. Within both leaf and stem fractions of the plants selection was for material of the highest available nitrogen content. This resulted in the sheep presenting themselves each day with material of a lower nitrogen content than that of the previous day. Evidence is presented to show that these selection preferences were exhibited more strongly the greater the amount of material present per unit area, i.e. the more mature the plant. The process of grazing in a horizontal plane, together with selection in a vertical one, is also described.
Effect of oestrogen and progesterone on the dilatability of the ovine vagina
Authors: Tomaszewska MW , Braden AWH , Turnbull KE
Published: November 2004

Twenty ovariectoinized ewes were given a single injection of stilboestrol or stilboestrol dipropionate. In ewes given stilboestrol, the rate of increase in apparent vaginal volume and the time required for return to basal levels were similar to those in entire ewes at the time of oestrus. The esterified hormone was slower and more prolonged in action. Pretreatment with progesterone did not affect the vaginal changes, though it enhanced and hastened the onset of behavioural oestrus. The results are presumptive evidence that the greater dilatability of the ovine vagina at oestrus is an oestrogenic response.
Opal uroliths from a ram
Authors: Baker G , Jones LHP , Milne AA
Published: November 2004

The exanimation of uroliths from a ram under the petrological microscope, and by chemical and physical techniques, revealed that the greater part of the uroliths consisted of opaline silica. Most of the opal was authigenic, being derived from the soluble silica ingested by the grazing animal in its plant feed. Possible mechanisms for the precipitation of authigenic opal are discussed. Some of the opal was present in the form of' particles which were identified as phytoliths, silicisponge spicules, and frustules of diatoms. The presence of these allothigenic particles in uroliths raises complex pathological issues which are discussed briefly.
Hornedness and polledness in sheep. 5. Some effects of the horn alleles on characters in the Merino
Authors: Dolling CHS , Carter NB
Published: November 2004

The influence on certain characters of the three alleles which affect horn growth has been investigated in three flocks of medium Peppin Merinos. These alleles have been named P, P', and p. The characters investigated were: greasy and clean wool weight per head, body weight, wrinkle score, fibre number per sq. millimetre of' skin, fibre diameter, staple length, clean scoured yield, crimps per inch, face cover, and, on some sheep, spinning count, character, colour, and handle. Comparisons between Pp and pp rams and ewes revealed that Pp rams had a significantly lower fibre number and a higher fibre diameter than their pp halfb-rothers, but there was no other evidence of any relationship between horn genotype and the phenotype of the above characters in either sex. In comparisons between Pp and P'p sheep, rams showed no significant differences, although they had the same hornedness phenotypes as Pp and pp rams. Pp ewes cut more clean wool and greasy wool than P'p ewes at 12 months of age, but not at 22 or 30 months. Pp ewes also had a higher fibre number at 12 months and a lower fibre diameter at 22 months than P'p ewes. In the third flock, comparison \\-as made between P'P' plus P'p ewes, which have female horns, and pp ewes, which have either scurs or knobs. In none of the above characters was there any significant difference between ewes with and without, horns. The presence of P had no demonstrable effect on spinning count, character, colonr, or handle in either the Pp v. pp or the Pp v. P'p comparison. Sire x hornedness genotype interactions were found in the Pp v. P'p comparisons of body weight at 22 months for rams and spinning count for ewes.
Mineralization of nitrogen and sulphur from sheep faeces.
Authors: Barrow NJ
Published: November 2004

Samples of sheep faeces were mixed with soil and incubated in conditions similar to those in a previous investigation with plant material. Mineralization of' nitrogen and sulphur from faeces is compared with that from plant material. The amount of nitrogen mineralized from faeces was closely related to the total Nitrogen content of the faeces, but faeces were more resistant to decomposition than was plant material and a smaller proportion of the nitrogen was mineralized. Similarly the amount of sulphur mineralized was closely related to the sulphur content of the faeces and the proportion of the sulphur mineralized was less than with plant material However, the nitrogen and sulphur present in faeces as only a proportion of the nitrogen and sulphur in the feed since much nitrogen and sulphur were excreted in the urine. It is pointed out that where plant material is eaten by an animal and both the urine and the faeces are allowed to return to the soil, the proportion of the nitrogen and sulphur mineralized will be greater than if the plant material were returned directly to the soil.
The cation exchange capacity of plant roots, and its relationship to the uptake of insoluble nutrients
Authors: Asher CJ , Ozanne PG
Published: November 2004

The cation exchange capacity (C.E.C.) of the roots of 20 plant species was measured by a rapid technique not involving toxic reagents or harmful temperatures. Significant differences between the root C.E.C. of various species were found, and with three exceptions, legumes > herbs > grasses. Nitrogen supply had little effect on the legumes and herbs, but significantly increased the C.E.C. of two grasses. The concentrations of calcium and phosphorus in the tops of plants utilizing rock phosphate were each positively correlated with root C.E.C. The concentration of phosphorus was not greater in the tops of plants with relatively large root systems.
Studies on frost injury to wheat. I. Laboratory freezing tests in relation to the behaviour of varieties in the field
Authors: Single WV
Published: November 2004

Factors influencing the reactions of different varieties of wheat to stem and ear frosting were studied under controlled conditions and in the field. Artificial freezing tests were successful in demonstrating varietal differences in resistance, but these were not always in agreement with behaviour under commercial cultivation. Thus, whereas the American winter wheat Cheyenne showed resistance superior to that of the Australian varieties Bencubbin and Gabo, the observed superiority of Bencubbin over Gabo in the field was not maintained under controlled conditions. A possible explanation for this anomaly lies in the unequal distribution of temperature which obtains within a crop. On several frosty nights the ears and stems of Gabo, owing to their more forward development, were observed to be in a colder zone than those of Bencubbin. These conditions were not reproduced in the freezing cabinet, and comparisons between plants at different stages of growth failed to show any marked change in resistance with age up to the time of ear emergence. The relationship between temperature of freezing and degree of injury was established under different sets of conditions. In one case interaction between the effects of temperature and variety showed that this factor may be of some importance in the interpretation of results of freezing trials.
The development of cuttings of the Washington navel orange to the stage of fruit set. IV. The effect of different nitrogen and phosphorus levels on fruiting cuttings
Authors: Bouma D
Published: November 2004

Washington Navel orange cuttings, which had flowered 6 months after striking and had set fruit, were subjected to three nitrogen and three phosphorus levels in factorial combination. Increasing nitrogen and phosphorus supply caused a relatively greater increase in the fresh weight of the peel and rag of the fruit than in that of the juice, and this was reflected in a greater diameter of the fruit, a thicker peel, and a decrease in the percentage juice content. The acidity and sugar content of the juice differed little between nitrogen levels, but a marked decrease in both was apparent with increasing phosphorus supply. The results are compared with those of a field experiment. The adverse effects of increasing nitrogen supply on fruit quality were similar in the two experiments. In the glass-house experiment, some improvement in fruit quality with increasing phosphorus levels was only apparent at the low nitrogen level. The dominant role of fruit development with respect to vegetative growth observed in the previous paper of this series was confirmed. Leaves on fruiting shoots showed considerably lower nitrogen and phosphorus contents than the remainder of the leaves, particularly at the higher levels of nutrition.
Parasitic gastro-enteritis of cattle: the effect of age on the infectivity of strongyle larvae
Authors: Durie PH
Published: November 2004

Experiments were carried out to determine whether aged infective larvae of the cattle strongyles Haemonchus placei, Cooperia punctata, C. pectinata, and Oesophagostomum radiatum were still able to complete their parasitic life cycle. Mature adult parasites were obtained in calves, reared worm-free, following the ingestion of larvae of H. placei stored on moist filter paper for 150 days or of larvae of Cooperia spp. and O. radiatum kept in water for a similar period of time. Some larvae of all species developed to adults after 182 days' exposure on pasture. Many larvae of O. radiatum survived under these conditions; but only very few of H. placei.
The cytology and reproduction of Paspalum yaguaronense (Henr)
Authors: Pritchard AJ
Published: November 2004

A high degree of sterility occurs in an introduction of Paspalum yaguaronense. Cytological and embryological studies have shown that the chromosome number is 2n = 20, and that the embryo sac develops normally. Sterility is due to an incompatibility system which prevents the growth of pollen tubes into the style. A self-fertile selection has been made in which fertilization occurs 4 hr after anthesis. Fertility probably arose by mutation of an incompatibility allele. The sterile plants will readily produce seed when pollinated by clones of the fertile plant. Because P. yaguaronense possesses a sexual method of reproduction and an incompatibility system, it could be useful in future breeding work within the genus Paspalum, which contains a number of apomictic species.
Death of root-nodule bacteria on drying
Authors: Vincent JM , Thompson JA , Donovan KO
Published: November 2004

A study has been made of the survival of Rhizobium trifolii, suspended in simple media and applied to glass beads and seeds of subterranean clover, and held in atmospheres of controlled relative humidity (R.H.) within the range 0–100%, at 26° and at atmospheric pressure. Under drying conditions, two distinct phases could be recognized: a period of approximately 24 hr in which the main loss of water occurred and in which there was rapid death, and a storage period in which the death rate was reduced. Cells of Rh. trifolii lost viability rapidly when suspended in glass-distilled water and spread on glass beads, under both drying (0 and 20% R.H.) and non-drying (100% R.H.) conditions. Suspension in 9% maltose, though without effect on rate of water loss, reduced the death rate considerably during drying and storage at low R.H., and permitted multiplication at 100% R.H. As a protectant during drying and storage, maltose was markedly superior to yeast extract, sorbitol, and five other sugars, including its ß-isomer, cellobiose. These materials were, however, superior to water alone, in contrast to sodium chloride and Ringer's solution (equiosmolar with maltose), which gave no protection. Low maltose concentrations (0.9 and 3.6%) were inferior to higher concentrations (9, 18, and 27%). Seeds of subterranean clover and a seed extract tested on beads increased the early death rate. This acceleration of death was not affected by maltose and was most marked at 100% R.H. and during the first few hours of drying (0% R.H.), when water was still abundant. Gum arabic gave some protection against this toxic action, as well as being slightly more protective than maltose on glass beads. The death rate during drying of cells in water appeared to be inversely related to the concentration of inoculum. Maltose removed any such dependence on inoculum size. Under conditions where survival during storage was measurable (maltose and glass beads), 60% R.H. was inferior to 0 and 20%.
A stringent test for the artificial rumen
Authors: Gray FV , Weller RA , Pilgrim AF , Jones GB
Published: November 2004

In each of three experiments the acetic, propionic, and butyric acids in the rumen of a sheep were labelled with 14C and a sample of the rumen contents was removed to an artificial rumen so that fermentations of the same substrates could be conducted simultaneously in vivo and in vitro. The in vitro fermentations were carried out in a specially designed artificial rumen of the "permeable" type in which the volume of the contents was kept constant while a continuous supply of artificial saliva was introduced. The relationships between the specific activities of the volatile fatty acids during a period of 2 to 3 hr indicated that the relative rates of formation of the acids were similar in the two systems, although in each experiment the fermentation appeared to proceed more slowly in vitro. It is considered that the procedure constitutes a stringent test for the correct functioning of an artificial rumen.
Studies on salt tolerance of sheep. IV. The tolerance of sheep for mixtures of sodium chloride and calcium chloride in the drinking water
Authors: Peirce AW
Published: November 2004

Six groups, each of six sheep, were fed in pens for 15 months on a ration of chaffed lucerne and wheaten hays. One group was offered rain-water to drink, another group was offered 1.30% sodium chloride, whereas the others were offered one of the following mixtures of sodium and calcium chlorides: 1.24 + 0.05, 1.19 + 0.10, l.09 + 0.20, and 0.98 + 0.30%. The intake of all saline solutions was higher than that of rain-water, ranging from 100% above for 1.30% sodium chloride to 20% above for 0.30% calcium chloride; the mean daily intakes for the entire experiment by the six groups were 2.6, 5.2, 4.6, 4.4, 3.8, and 3.11, respectively. The intake also increased in all groups with temperature, being 45–60% higher in the hottest months than in the coldest months. The saline drinking waters had no effect on the concentrations of potassium, magnesium, or chloride in the blood plasma, but did result, for a considerable portion of the experiment, in lower concentrations of sodium and higher concentrations of calcium in the plasma as compared with the concentrations of these electrolytes in the plasma of sheep drinking rain-water. None of the solutions used in the experiment had any adverse effect on the general health, food consumption, weight increase, or wool production of the sheep.
A striate mosaic virus disease of grasses and cereals in Australia, transmitted by the cicadellid Nesoclutha obscura
Authors: Grylls NE
Published: November 2004

A virus disease of perennial grasses and small grain cereals, not previously studied in Australia, was found in northern New South Wales and Queensland. The disease does not appear at present to be of great economic importance, but the virus has many properties in common with wheat striate mosaic virus of North America. The vector is the cicadellid leafhopper Nesoclutha obscura Evans. Ten other cicadellids, two delphacids, and two cereal aphids did not transmit the disease. Evidence is presented that, unlike the majority of leafhopper-borne viruses, the virus causing the disease inhabits the mesophyll. Some studies of the virus-vector relationships, the host range, and symptomatology, and comparisons of these with those of other grass and cereal viruses are recorded.
The influence of higher volatile fattty acids on the intake of urea-supplemented low quality cereal hay by sheep
Authors: Hemsley JA , Moir RJ
Published: November 2004

The intake of milled oaten hay (0.7% nitrogen) by sheep was markedly increased by the addition of urea. Where molasses or an equivalent level of sucrose was fed in addition to urea no further significant increase in hay intake occurred, although there was an increase in the concentration of microbial protein (trichloroacetic acid-precipitated nitrogen). The addition of 0.56% of a mixture of isobutyric, n-valeric, and isovaleric acids with urea increased the microbial protein concentration to a similar extent but, in addition, significantly increased the intake of hay. All urea treatments resulted in significant increases in the rate of cotton thread digestion, in the rate of passage of food through the animal, and in the concentrations of total volatile fatty acid (V.F.A.) and ammonia nitrogen in the rumen, and caused an improvement in nitrogen balance from negative to positive values. Since the amount of energy added in the V.F.A. mixture was negligible compared with the molasses or sucrose supplements, it is suggested that the V.F.A. directly stimulated microbial growth in the rumen. The implications of these findings are discussed in relation to the supplementation of low-quality roughage and the definition of 'quality' of ruminant feedstuffs.
The effects of infection with Haemonchus contortus on the sodium and potassium concentrations in the erythrocytes and plasma, in sheep of different haemoglobin types
Authors: Evans JV , Blunt MH , Southcott WH
Published: November 2004

The anaemia produced by Haemonchus contortus was characterized by a marked reduction in haemoglobin concentration and packed cell volume, accompanied by a marked rise in the concentration of potassium in the erythrocytes [Ke+] and a fall in the concentration of sodium [Nae+]; total [Ke+ + Nae+] remained steady. Infection was associated with reduced food intake and a lowered concentration of plasma protein, but plasma potassium and sodium remained constant. During the first 10 weeks of the experiment both the infected and the control sheep developed an anaemia of unknown aetiology, characterized by raised [Ke+], [Nae+], and [Ke+ + Nae+] values, and plasma protein concentrations.The evidence presented seems to suggest that sheep of haemoglobin type A may harbour fewer worms than sheep with haemoglobin type AB following infection with H. contortus.
Accumulation of nitrate in oats infected with barley yellow dwarf virus
Authors: Stubbs LL , Walbran WI
Published: November 2004

A comparison was made of the nitrate levels of healthy Algerian oats and those infected with barley yellow dwarf virus (BYDV), the plants being grown on three soil types in containers in an insect-screened glass-house, under conditions of low nitrogen nutrition. The nitrate level of virus-infected plants was significantly higher than that of healthy plants, and within the range considered to be toxic to ruminants. In plants grown in a peat-sand mix with abundant applied nitrogen, infected oats were not markedly dwarfed; their foliage dry weight was not significantly less than that of healthy oats, but nitrate accumulation was significantly less. The possible significance of the association between nitrate accumulation and BYDV infection in oats is discussed in relation to nitrate poisoning of livestock.
The effects of carbon dioxide and oxygen concentrations on superficial scald of Granny Smith apples
Authors: Roberts EA , Hall EG , Scott KJ
Published: November 2004

In the past, experiments on controlled atmosphere storage have tested specific combinations of carbon dioxide and oxygen, usually in a manner which precludes determination of the effect of change in concentration of these gases. The data from the series of trials discussed in this paper permitted an investigation of the effect of concentrations of carbon dioxide and oxygen on the incidence of scald with simple and multiple linear regression techniques. The method was applied to data from three types of controlled atmosphere storage:

(1) Carbon dioxide 2.5–10% at 2.5% oxygen,

(2) Oxygen 1.25–20%, at near zero carbon dioxide,

(3) Carbon dioxide 3.3–10.9% oxygen 2.2–16%. The relation between scald (Y), carbon dioxide concentration (x), and the reciprocal of oxygen concentration (z), was described by the regression equation: Y = y + b(x – x) + c(z – z), which implies that scald is directly proportional to carbon dioxide concentration and indirectly proportional to oxygen concentration. The effects of changes in concentration of the gases, as estimated by the regression coefficients, were consistent for size of fruit, season, and orchard, but the effect for oxygen was dependent on the method of maintaining the atmosphere. Good control of scald was obtained with low oxygen atmospheres, even after storage for 6–7 months.
Frequencies of annual species of Medicago on brown acid soils of the Macquarie region of New South Wales
Authors: Hely FW , Brockwell J
Published: November 2004

The distribution of naturalized annual species of Medicago (medics) was studied on the brown acid soils of the Macquarie region of New South Wales, an area approximately 80 miles by 40 miles in extent. Four soil-landscape units were defined and one of these units was subdivided geographically into three parts. Four medics were found: Medicago minima (L.) Bart. and Medicago laciniata (L.) Mill. were by far the dominant annual legumes, occurring in many places at high frequency; Medicago denticulata Willd. and Medicago praecox DC. occurred at few sites and only at low frequency. Marked differences with respect to frequencies of medics were found both between soil-landscape units and the geographical subdivisions. On each unit and subdivision the frequency of M. minima in quadrats was consistently higher than that of M. laciniata. Association between M. minima and M. laciniata in quadrats was variable, but tended to be positive where these two medics occurrcd at low frequency and negative where they occurred at high frequency.
Preliminary trials of the application of antitranspirants under field conditions to vines and bananas
Authors: Gale J , Poljakoff-Mayber A , Nir I , Kahane I
Published: November 2004

(1) During 3 years of field trials, antitranspirant treatment of irrigated late season Muscat Hamburg vines caused a 2–3 week delay in the ripening of the grapes. It is suggested that this was due to the improved water balance of the plants. Under Israeli conditions, the staggering of the harvest and the higher prices obtained at the end of the season made this treatment highly profitable. Under non-irrigated conditions, the yields of treated vines were 14.5% higher than those of the controls. (2) During seven irrigation cycles, extraction of water from the soil by antitranspirant- treated banana plants was 21–44% less than that of untreated plants. There was no significant effect of the treatment on the growth or yield. The results on water extraction, although statistically significant, were obtained during one season only and from an experiment on a very small scale.
Corrigendum - Nutrient potential and capacity. I. The concepts of nutrient potential and capacity and their application to soil potassium and phosphorus
Authors: Barrow NJ , Ozanne PG , Shaw TC
Published: November 2004

The theoretical basis for the measurement of nutrient potential is examined and its application to soils is discussed. It is suggested that nutrient potential should be measured in standardized units by defining chemical potential relative to a given standard state, such as the usual standard state of solution chemistry. The unit for all nutrient potentials would then be calories per equivalent. The nutrient capacity is regarded as the ability of a soil to resist change in potential. It is therefore indicated by the shape of the curve relating potential to the quantity of the nutrient in the solid phase. For potassium the relationship between potential and exchangeable potassium was found to be curvilinear, so that each decrement of potassium makes the next decrement more difficult to remove. Curves for five soils differed from each other. This was not only because of differing cation exchange capacities but also because of differences among the types of colloids. The relationship between phosphorus potential and phosphorus sorption was also found to be curvilinear and the slopes for the various soils again differed from each other. During equilibration with phosphate, microbial activity caused biological immobilization of phosphorus. This could be controlled by adding mercuric chloride or chloroform, but toluene was less effective.
The inheritance of grain hardness in wheat as measured by the particle size index
Authors: Symes KJ
Published: November 2004

The difference in particle size index between a hard wheat (Falcon) and a soft wheat (Heron) is shown to be due to a single major gene. Tests of F2 populations of seven other crosses between hard and soft wheats indicate that this is not uncommon. The existence of minor genes which modify the action of the major gene in determining the hardness or softness of wheat grain is also demonstrated. In at least one case (Spica) a different level of hardness appears to be due to a different major gene from that found in Falcon and not to modifying genes. The conversion of a hard wheat to a soft wheat or vice versa can be achieved by backcrossing. The grain hardness of the new wheat will be influenced both by the hardness of the donor parent and by the degree to which modifying genes are carried over. This demonstration of the simple inheritance of grain hardness as measured by particle size index is of significance to wheat improvement programmes.
Nutritional status and intake regulation in sheep. III. The relationship between improvement of nitrogen status and increase in voluntary intake of low-protein roughages by sheep
Authors: Egan AR
Published: November 2004

Relationships between the intake of feed by sheep fed on low-protein roughage and the improvement of the sheep's nitrogen status by duodenal supplementation are described. Results of experiments suggest that an increased protein intake initiated an improvement in dry matter and digestible energy intake which was related to improved nitrogen balance. An increased rate of passage of food through the alimentary tract did not alone account for greater intakes, since at a given rate of passage, the intake was higher when the sheep were in higher nitrogen balance; this suggested a higher level of 'fill' of the alimentary tract with improved nitrogen status. Data from other experiments where nitrogen supplements were given in the diet were examined similarly and similar conclusions were reached. The possible roles of protein absorbed by the sheep and of certain other nutritional factors are discussed in relation to possible mechanisms for regulating roughage intake by the sheep.
The value of Atriplex (Saltbush) and Kochia (Bluebush) species as food for sheep
Authors: Wilson AD
Published: November 2004

Penned sheep were fed on species of Atriplex or Kochia, either alone or as supplements to a roughage diet. The intake and digestibility of the diets, and the weight change of the sheep were recorded. The digestible dry matter intake of A. nummularia and A. vesicaria was sufficient for maintenance of the sheep, provided that fresh water was available. There was little seasonal change in the quality of the Atriglex diets. The intake of a protein-deficient roughage was not altered by the addition of 150 g dry matter of Atriplex or Kochia as a supplement. Body weight loss was decreased or gain increased, but neither significantly, by the addition of these supplements which were high in nitrogen.
Genetic factors affecting the milk intake of lambs
Authors: Moore RW
Published: November 2004

The actual amount of milk produced by a ewe is influenced both by her own potential to produce milk and by the potential of the lamb to obtain it. Two experiments were carried out to investigate the relative importance of these factors. In each experiment there were two genetically different groups of ewes, of which some reared their own single lambs and some reared single lambs from the other group fostered onto them. In both experiments, the effect of the genotype of the lamb was greater than that of the ewe. In the first experiment, during the period 6–24 days after parturition, ewes suckling strong-wool lambs produced 7.2 g/hr more milk than those suckling Peppin lambs, while the strong-wool ewes themselves produced only 4.6 g/hr more than the Peppin ewes. In the second experiment, during the period 0–28 days after parturition, ewes suckling Corriedale lambs produced 11.6 g/hr more milk than those suckling strong-wool Merino lambs, whereas the Corriedale ewes themselves produced only 4.4 g/hr more than the strong-wool Merino ewes. The lamb genotype effects were statistically significant. In a third experiment, in which the strong-wool and medium-wool Merinos were compared when suckling twins, the strong-wool exceeded the medium by 10.8 g/hr in milk production for the period 6-24 days after parturition. Some implications of the results are discussed.
Distribution and turnover of water in Merino sheep selected for high wool production
Authors: Macfarlane WV , Dolling CHS , Howard B
Published: November 2004

Estimates of the distribution of body water and the rate of water turnover were made on medium Peppin Merino ewes grazing on Mitchell grass association pasture in south-western Queensland during January and November. It so happened that the January measurements were made while the sheep were on lush green pasture following good rains, and that the November measurements were made on dry pasture after a number of months of low rainfall. The estimates made on each sheep included those of plasma volume, extracellular volume, total body water, plasma protein, and water turnover per 24 hr. The ewes, which were approximately 4¼ and 4¾ years of age at the times of measurement, were drawn either from a flock which had been under selection for high clean wool production per head or from a control flock in which all animals used for breeding had been chosen at random from those available. Twelve ewes from each flock were observed in January, and a different set of 10 ewes from each flock was observed in November. Body fluid compartments, as millilitres per kilogram body weight, were greater during the wet: than during the dry period. Plasma volumes were significantly greater in January than in November by 10.3% for the selected ewes and 18.2% for control ewes. The estimates of extracellular volume showed a similar significant difference between the months (15.4% for selected ewes and 17.4% for controls). The January measurements of total body water exceeded the November observations by 9.6% in the selected ewes and 11.2% in the control ewes, both increases being significant. In none of these three characteristics, however, were the selected ewes significantly different from the control ewes during either January or November. The 24 hr turnover of water in millilitres per kilogram body weight was significantly greater in January than in November by 30% for selected sheep and 51.1% for controls. The high water content of pasture during January greatly reduced the free water intake from troughs (ratio of respective water intakes of control and selected sheep was 100/123.7 in November and 1.3/1.5 in January); and the low dry matter content of the food became the major determinant of water turnover. When grazing relatively dry grasses in November, the selected sheep turned over significantly more water than did the controls (ratio control to selected was 100/113.7), but in January the turnovers were not significantly different (control/selected = 137.5/128.7).
The special senses in grazing animals. I. Sight and dietary habits in sheep
Authors: Arnold GW
Published: November 2004

The diets and productivity of sheep unable to see what they ate (blinkered) and control (unblinkered) sheep were compared in a number of experiments. Diet composition differed for control and blinkered sheep under some pasture conditions. These differences are attributed to the use of sight by sheep to orientate themselves whilst grazing; habit of grazing was altered in blinkered sheep. Preference ranking of species was unaltered by blinkering sheep.
The photoperiodic sensitivity of some spring wheats with special reference to the variety thatcher
Authors: Pugsley AT
Published: November 2004

Earlier studies of the processes leading to flowering in spring wheats have been extended to embrace a genetic analysis of photoperiodic sensitivity in several spring varieties. The American variety Thatcher proved particularly sensitive to the short days experienced in the greenhouse during the winter months. Compared with Selkirk, Thatcher is later under short days, and this lateness appears to be conditioned by a second minor gene over and above that already recognized in Selkirk. The backcrossing procedure has been used to establish two new recombinant genotypes intermediate in behaviour between the parental varieties Triple Dirk and Thatcher. Abnormalities in ear development of sensitive varieties like Thatcher were consistently produced when plants raised under short days were transferred to long days soon after the estimated time of initiation of floral primordia.
The effect of level of feeding on acetate tolerance in the sheep
Authors: Weston RH
Published: November 2004

Intravenous acetate tolerance tests were conducted on sheep offered chopped lucerne hay at six levels of intake, a ground and pelleted mixture of lucerne hay, maize, and peanut meal at two levels, and a low quality roughage ad libitum. The rate of disappearance of acetate injected intravenously increased with increase in the levels of both feed intake and digestible energy intake. There was no difference between diets in the rate of disappearance when the diets provided similar amounts of digestible energy. Changes in rate of disappearance occurred within 7 days of changes in level of feeding. It was concluded that care should be exercised in interpreting differences between diets in acetate tolerance when the diets provide widely differing quantities of digestible energy.
Studies of face cover in the New Zealand Romney Marsh sheep. II. The measurement of face cover and of factors associated with differences in face grades
Authors: Cockrem F
Published: November 2004

Face cover was measured as poll staple length and the length of the nose free of visible wool growth. Forty open-faced and 80 woolly-faced ewes were measured every June for five years. While differences in the measurements occurred between the grades, analyses showed that neither measurement, nor a combination of them, discriminated satisfactorily between grades over the full range of face cover. Within a face-cover grade, poll staple length was positively correlated with the midside staple length. Between the grades the relationship was a negative one. Follicle characteristics were measured in facial skin from seven open-faced and 10 woolly-faced sheep from the same flock. Open-faced sheep had the larger primary follicles but smaller secondary follicle diameters. Thus open-faced sheep had a dp/ds ratio of 2.3 and woolly-faced sheep one of 1.4. Further skin samples from six rams and seven wethers at 1 year of age showed that castration had reduced primary follicle diameter (57 and 41 µ) without changing the face cover. Also ewes and ovariectomized ewes showed a difference in SIP ratio on the face (1.9 and 2.5) with no difference in face cover. It was concluded that primary follicle size was not an immediate determinant of face cover but that factors external to the facial follicles were more likely to be of importance.
Physiological and ecological studies on the oestrogenic isoflavones in subterranean clover (T. subterraneum L.) IV. Effects of zinc deficiency in clover seedlings.
Authors: Rossiter RC
Published: November 2004

Results of a glasshouse experiment, conducted on an acutely zinc-deficient soil, are presented. At day 29, the cotyledons and unifoliate leaves of zinc-deficient plants showed higher isoflavone concentrations, and markedly higher total isoflavones per leaf, than did those of plants supplied with zinc. At day 47, however, when the "little leaf" condition was well advanced in the zinc-deficient plants, trifoliate leaves of the deficient plants were lower in isoflavone levels (and especially in isoflavones per leaf) than those of normal plants. The patterns of isoflavone distribution correspond with, and are thought to result from, effects of zinc deficiency in the seedling stage on photosynthetic accumulation in plant parts. It is considered that zinc deficiency in the field is unlikely to affect the incidence of "clover disease".
The distribution of oestrogenic isoflavones in the genus Trifolium
Authors: Francis CM , Millington AJ , Bailey ET
Published: November 2004

Of 100 Trifolium species tested prior to and during early flowering, 14 had isoflavone contents comparable with that of subterranean clover, and seven of these were closely related taxonomically. Intervarietal variation in isoflavone content was found in self-fertilized species containing isoflavones, but not in the cross-fertilized T. pratense L. In all species the isoflavones genistein, biochanin A, and formononetin were in glycosidic forms. The same isoflavone glycosides were represented in all species containing isoflavones in quantity. No species contained significant quantities of coumestrol, and many of the common naturalized species were virtually free of known oestrogens.
Nutrient potential and capacity. III. Minimum value of potassium potential for availability to Trifolium subterraneum in soil and in solution culture
Authors: Barrow NJ , Asher CJ , Ozanne PG
Published: November 2004

Plants of subterranean clover (Trifolium subterraneum L.) were grown in a range of soils until the supplies of potassium were exhausted. The potassium potential of each soil was then measured by determining the free energy of exchange of potassium for calcium plus magnesium. In soils of very high buffering capacity the potassium potential of the exhausted soil was about –6000 cal/equiv. In soils of lower buffering capacity the potential of the exhausted soil was higher but this may have been an artefact due to release of potassium from fine root material left in the soil at harvest. Subterranean clover plants were also grown in large volumes of well-stirred nutrient solutions which were held at a range of potassium concentrations. Again it was found that the plants were unable to take up potassium when the potassium potential was about –6000 cal/equiv. It is suggested that the potentials were similar because diffusion gradients were negligible in the exhausted soil and also in the swiftly flowing solutions. At potentials above –6000 cal/equiv. availability of potassium appeared to be greater in the solution cultures than in soils. It is suggested that this occurred because, in soils, the uptake of potassium causes the potential at the plant root to be lower than in the bulk of the soil.
The physiological assessment of the nutrient status of plants. IV. The effect of the interaction between nutrient elements of leaf area responses
Authors: Bouma D , Dowling EJ
Published: November 2004

Experiments were carried out with subterranean clover in water cultures to study the effect of interactions between phosphorus, sulphur, and nitrogen. These elements were varied in pairs, and leaf area responses measured after transfer to complete solutions and to solutions without one of the two previously varied elements. Leaf area responses after transfer of plants deficient in phosphorus as well as in sulphur revealed both deficiencies when they had been of approximately equal intensity. When elements were deficient to differing degrees, leaf area responses depended on the relative intensities of the deficiencies. With deficiencies of sufficiently differing intensities, leaf area response patterns after transfer showed a deficiency of only one element because its supply had been low enough to mask the effect of the other deficiency. Transfer of plants deficient in only one element confirmed that there is no simple relation between the nitrogen status of the plant and the induced leaf area responses. The results also confirmed the feasibility of at least a qualitative assessment of the phosphorus or the sulphur status of plants.
Investigation of suspected grapevine viruses in South Australia
Authors: Francki RIB , Crowley NC
Published: November 2004

Evidence is presented that a strain of grapevine yellow mosaic virus is present in South Australia, but its incidence is very low and a nematode vector has not been found in affected vineyards. The "dying arm" disorder of vines is not due to infection by fanleaf virus as previously suspected, and typical fanleaf virus has not been found in the State. A new grapevine disorder affecting the variety Clare Riesling is also described.
Epidemiology of blue mould (Peronospora tabacina Adam) of tobacco in the Ovens Valley district of Victoria. II. Disease severity
Authors: Paddick RG , Hill AV , Green S
Published: November 2004

Tobacco fields in Victoria were rated for severity of blue mould disease during six consecutive seasons. The disease was most severe on plants infected when less than 9 inches in height and slight on plants infected when near or at the flowering stage. Disease severity on leaves increased rapidly during the 3-week period commencing about December 25. The disease can be destructive in leaves, especially on plants growing in soils recently under pasture. The basal stem infection phase of blue mould is most destructive. Avoidance of stem infection is the major requirement for control. Basal stem infection was not of importance in years when fungicides were applied for control of leaf infection. Soil factors promoting lush growth, and weather conditions favouring sporulation and infection early in the season, were the main factors influencing disease severity. Resistant varieties need to have leaf resistance to reduce spore numbers, and stem resistance to prevent loss of entire plants.
Studies on the diet of grazing animal. III. The effect of pasture species and pasture structure on the herbage intake of sheep
Authors: Arnold GW , Dudzinski ML
Published: November 2004

The digestible organic matter intake (DOMI) of 35-kg year-old Merino wethers was studied on seven pasture types. For each pasture type a range of pasture conditions was used. Relations between DOMI and in vitro diet digestibility (D), total dry matter per acre (TDM), green dry matter per acre (GDM), mean leaf length of green herbage (LL), and number of leaves per unit area (LN) were investigated by multiple regression analyses. In general where there was a limited range of TDM, this variable and D were the major contributors to variation in DOMI. This pattern was associated with a low GDM/TDM ratio, and ability to select herbage high in D was important. Over a wider range of TDM, D was replaced by GDM or LL as a major contributor to variation in DOMI. Variations in this general pattern are discussed. Not only is the DOMI of grazing sheep influenced to different degrees by different pasture characteristics in different situations but the relations differ for different classes of sheep. Analysis of simple relations between DOMI and TDM shows different asymptotes on one pasture type for different classes of sheep.
Corrigendum - Pharmacology and toxicology of carbon tetrachloride in the sheep. IV. Reduction and augmentation of toxicity by selenium.
Authors: Kondos AC , McClymont GL
Published: November 2004

Susceptibility of sheep to toxic effects of carbon tetrachloride (CCl4) was assessed by determining the increase in plasma levels of isocitric dehydrogenase (ICD) and glutamic transaminase (GOT) and by other criteria. Susceptibility was increased by oral administration of 1 mg of selenium (Se) as sodium selenite plus 100 i.u. of tocopherol acetate on alternate days for 120 days, 2 mg Se per day for 21 days, and 6 mg Se per day for 6 days, before dosing with CCl4. Susceptibility was reduced by smaller total amounts of Se, and by oral doses of 6 mg Se per day for 3 days, a single oral or intramuscular dose of 5 or 12 mg c. 20 hr, or 5 or 12 mg orally 10–20 min, before dosing with CCl4. One 5 mg dose at 20 hr and a second 20 min before CCl4 was more effective than either alone. Sheep from two different sources differed considerably in their susceptibility to CCl4. In the more susceptible sheep Se administration reduced susceptibility to a level comparable with that shown by the naturally resistant animals. Administration of Se to sheep dosed with CCl4 and then given a high-protein diet resulted in lower GOT levels, milder clinical signs, and a great reduction in mortality. In field tests on properties with a recent history of CCl4 poisoning, oral administration of 5 mg Se about 20 min before CCl4 significantly reduced susceptibility. Administration of Se to fluke-infested sheep did not protect the liver fluke (Fasciola hepatica) against CCl4.
Diurnal and seasonal changes in bovine respiratory functions in a subtropical climate
Authors: Berman A
Published: November 2004

The respiratory responses of four Israeli-Holstein heifers sheltered from direct solar radiation were measured every 4 hr during 4 consecutive days in early spring and again in late summer. Two of the animals were fed according to Fredricksen's standard, and two ad libitum. Average atmospheric conditions were 18.4°C and 65° R.H. In spring and 27.5° and 75° in summer. In spring no marked diurnal variation was evident in either ventilation rate or respiration rate, whereas in summer a well-defined cycle was evident. Tidal volume showed a distinct cycle in spring with the lower volumes occurring in the day-time, while in summer the variation was almost nil and absolute levels were lower. In both seasons the animals fed ad libitum had lower tidal volumes and a more restricted cycle. In both seasons, ventilation rates and respiration rates were not correlated with diurnal variation in climatic parameters. Ventilation rates increased by only 4% from spring to summer in both feeding groups, while respiration rate was doubled. The response of respiration rate to temperature was of the order of Q10 = 2, for changes from season to season only. In both seasons respiratory vaporization followed very similar and pronounced diurnal cycles, the maximum value being attained at 0830 hours. Higher rates were found in both seasons for the group fed ad libitum, owing mainly to consistently higher vaporization rates in the afternoon and evening hours. The diurnal cycle in vaporization was due mainly to changes in moisture content of the expired air. The partial effect of respiration rate on the moisture content of expired air and on moisture exhaled per minute was highly significant, while that of ventilation rate was not significant. The increase in absolute atmospheric humidity from spring to summer was associated with an increase in absolute humidity in the exhaled air, but this did not prevent a 12.6% reduction in respiratory vaporization.