bluuebunny/crossref_metadata_2025 huggingface dataset:
Influence of rams on ovarian activity and oestrus in Merino ewes in the spring and early summer
Authors: Radford HM , Watson RH
Published: November 2004

The occurrence of oestrus and ovulation and the changes in the vaglnal contents were studied in Merino ewes following the introduction of vasectomized rams at various times during the spring and early summer. The ewes were in an anoestrous state when the observations were commenced. Except in occasional ewes oestrus did not appear until early December. It had occurred in all except a few ewes by early January. In most ewes among which rams were introduced on October 26 or November 18, it occurred about a week earlier than in ewes among which rams mere not introduced until December 8, and ewes among which rams had been running continuously. In at least 80 per cent, of animals in which both were studied, oestrus was accompanied by massive desquamation of the vaginal epithelium and it was preceded by one or more periods of massive desquamation. Between December 8 and December 14, masses of desquamated epithelial cells were present in the vaginal contents in few only of the ewes which were held separate from rams, but in almost all ewes among which rams were introduced on December 8 (group 4), and in most of the em7es which were running continuously with rams (group 6). They first appeared in the ewes of group 4 between December 11 and December 14, 3-6 days after the introduction of the rams, whereas they were already present in almost all of the ewes of group 6 by December 11.Corpora lutea compatible with ovulation shortly after December 8 were present in most ewes among which rams were introduced on that day, and in few ewes which were held separate from rams. The significance of these results is discussed.
Fat lamb studies in Victoria. II. The interaction between pre- and post-natal planes of nutrition on the production of wool and lambs by crossbred sheep
Authors: Papadopoulos JC , Robinson TJ
Published: November 2004

The interactions between two planes of pre- and post-natal nutrition of grazing ewes and the level of fertility on: ( a ) birth weight of the lamb, ( b ) its subsequent growth rate, and ( c ) wool growth, were determined in 140 crossbred ewes (52 Romney Marsh X Merino, 88 Border Leicester X Merino). The effectiveness of pregnant mare serum gonadotrophin (PMS) , injected on the 12th to 14th day of the oestrous cycle, for raising fertility ' was also investigated. Romney cross ewes had commenced their breeding season before January 21, a t least 3 weeks earlier than Border Leicester cross ewes. They lambed correspondingly earlier. The overall lambing percentage was very high (139 per cent.). PMS had no significant effect. There was no breed difference. Low- and high-plane ewes gained an average of 20 and 54 lb respectively during pregnancy. The mean weight of the conceptus was 34 lb (twins 39 Ib, singles 25 lb). Hence low-plane ewes lost an average of 14 lb body tissue as compared with a gain of 20 lb by high-plane ewes. Mean birth weights of lambs - single and multiple pregnancies - from the two nutritional groups were indistinguishable. Lamb losses and lambing troubles were fewer in the low--plane group. There was no interaction of pre- and post-natal nutrition on subsequent lamb growth rate. Post-natal plane of nutrition, sex of the lamb, and number reared all had highly significant effects on lamb growth rate. There were also significant interactions between plane of nutrition of the ewe and number of lambs reared and sex of lambs. Wether lambs needed the best possible nutritional environment fully to exhibit their inherent superior growth rate over ewe lambs. Restricted feed intake either in pregnancy or in lactation reduced wool growth to approximately the same degree. Although birth and weaning weights were affected by the number of lambs born and reared, wool production of the dam was not affected.
Renovation of Phalaris pastures with special reference to nitrogen and sulphur relationships
Authors: Barrow NJ
Published: November 2004

Renovation of phalaris (Phalaris tuberosa L.) pastures by mouldboard ploughing resulted in an increased yield of phalaris but a decreased yield of other species. Only at one of three sites was there a net increase in yield. The increased yield of phalaris may have been due to its greater ability to survive the fairly drastic ploughing treatment. The phalaris then had a competitive advantage when the pasture grew again. From data for soil ionic nitrogen, plant response to nitrogen and sulphur, and chemical analysis of plant material, it was concluded that the increase in yield was due to greater availability of nitrogen and sulphur, indicating accelerated breakdown of organic matter. This effect was considered to be due to the temporary prevention of plant growth, since the continual removal of ionic nitrogen by plants would tend to reduce the nitrogen available to microorganisms, thus widening the carbon : nitrogen ratio. A similar competition for sulphur may also be important. Recurring sulphur deficiency due to infrequent applications of fertilizer may be important in the decline of pastures on sulphur-deficient soils. The clover fraction would be particularly affected since grasses are considered to compete strongly with clovers for sulphate. The data for ionic nitrogen in soil showed that high exchangeable ammonium occurred during the winter months.
Reactions of calves to infestation with the stomach worm, Haemonchus placei (Place, 1893) Ransom, 1911
Authors: Roberts FHS
Published: November 2004

Studies aimed a t determining the factors responsible for haemonchosis in cattle are reported. Observations on natural populations of Haemonchus placei confirmed the conclusions of Roberts, O'Sullivan, and Riek (1932) on the acquisition of resistance to this species and on the relationships of peak egg counts to the age of the animal and season of the year. Most of the 400 calves on which these observations were based developed a strong resistance and suffered no apparent ill effects; others only became resistant after suffering clinical haemonchosis; and about 8 per cent. either failed to develop resistance or lost it and died. Experiments with single doses, spaced doses, and continuous doses of larvae showed that H. placei has a comparatively short patent period. The trend assumed by the egg counts, irrespective of the method of infestation, was very similar, reaching its peak about the 6th to 10th week and thereafter rapidly declining to remain a t low levels. Calves on a 12 : 1 mixture of oaten and lucerne chaff gave much higher egg counts than calves on good quality lucerne alone, but the infestations did not vary in their persistence. A strong resistance was acquired, even from a single dose of larvae. This was shown by the failure of a test dose of larvae, administered after the egg count had been at low levels for some weeks, to cause any increase in the egg count; and by the presence, several weeks later a t autopsy, of relatively few adult worms, most of which were undersized with females containing few or no eggs. There were also numerous fourth stage larvae which had evidently persisted in this stage for many weeks. That so many immature worms occurred in resistant animals may signify that these young stages could be extremely important in the epidemiology of haemonchosis. "Selfcure", as defined by Gordon (1948) for H. contortus in sheep, could not be produced experimentally with H. placei in cattle, but egg count trends suggest that this type of reaction may sometimes occur among natural populations before resistance is finally acquired. Circulating antibodies could not be detected in experimentally infested animals. They were found, however, in animals with natural infestations of mixed species, and it is probable that in the latter case they were associated rather with Trichostrongylus than with Haemonchus. Data on egg counts in relation to the number of adult female worms present in experimentally infested calves strongly suggest that whilst the animal remains susceptible to infestation, egg counts are usually an accurate index of the degree of infestation, but that when resistance occurs the egg count is of little value for this purpose.
Distribution of zinc and copper in subterranean clover (Trifolium subterraneum L.) grown in culture solutions supplied with graduated amounts of zinc
Authors: Riceman DS , Jones GB
Published: November 2004

The distribution of dry weight and of zinc and copper at different stages of growth has been examined in Trifolium subterraneum L. var. Bacchus Marsh grown in culture solutions to which graduated amounts of zinc were added. Several characteristics of the growth of the plants were assessed quantitatively. Symptoms of zinc deficiency developed in cultures which were supplied with suboptimal amounts of zinc.
Relationships among clean wool weight and its components. I. Changes in clean wool weight related to changes in the components
Authors: Turner HN
Published: November 2004

This paper is the first of a series presenting results from selection experiments with medium-wool Merino sheep, initiated by the Commonwealth Scientific and Industrial Research Organization (C.S.I.R.O.) in 1947. Clean wool weight (W) is discussed in relation to its five components: smooth body surface area (S), degree of skin wrinkling (R), fibre number per unit skin area (X), fibre cross-sectional area (A), and staple length (L). Statistical difficulties are encountered in relating a whole to one of its parts. Various methods have been used in the past, a common one being the gross correlation between clean wool weight and a component. It is shown that, given the variances and covariances of the components, and assuming that all relationships are mainly linear, this gross correlation can be predicted. The influence on the gross correlation of the relationships among the components is discussed, and it is shown that N and L will give the highest correlations with W for a range of values of phenotypic variances and covariances of the components which have been reported in the literature. Some selected combinations of extreme values, which might be encountered in specific strains, will increase the importance of other components. A study of the phenotypic and genetic variances and covariances of the components, and of the factors influencing them, is therefore likely to be more rewarding than a study of the gross correlations between clean wool weight and a component. One difficulty with the gross correlation technique is that if the variances of some components were more inflated by sampling errors than others, the correlation coefficients would be biased. A simple method, the "percentage deviation technique", is presented, which analyses means, and so avoids this possible bias. It has the added advantage of apportioning variation in clean. wool weight among the five components. Use of this technique on data from the C.S.I.R.O. selection experiments shows that in this flock N and L are more closely associated with W than are the other components. In each case the association is positive and accounts, on the average, for 0.3-0.4 of the phenotypic variation in W. There is little difference between the two components in their phenotypic association with W, but there is an indication that N may have a higher genetic association. Selection for W has increased N and L, as well as W itself, but has not changed body size.
Utilization of heterosis in poultry
Authors: Morley FHW
Published: November 2004

Records were analysed of 500-day production, egg weight, 11-week and mature body weight, sex maturity, and broodiness of the crossbred progeny of inbred lines of Australorps mated to White Leghorns, and inbred lines of White Leghorns mated to Australorps. Clear differences between lines of both breeds mere found in most characters, indicating the presence of potentially useful amounts of additive genetic variation. Non-additive genetic variation was also found to be present in varying degrees in different characters. Because of the difficulties of developing and maintaining inbred stocks of poultry, and the importance of sex-linked characteristics in some commercial environments, a scheme is proposed which may enable heterosis to be exploited without the use of inbred material. The basis of this scheme is the combination of the White Leghorn sex chromosome, with varying proportions of Australorp and White Leghorn autosomes, in a new breed. Assuming that the heterosis observed in the F1 is due to elimination of certain biochemical blocks determined by recessive genes, the formation of the new breed should enable the methods of closed flock breeding to be used in material at a higher level of production, and likely to contain more genetic variability, than either parent breed.
Methionine supplements in chicken diets. IV. The effect of DL-Methionine supplementation over full and part of growing period on growth and efficiency of cockerels from the reciprocal crosses of White Leghorns and Australorps
Authors: McDonald MW
Published: November 2004

The commercial value of DL-methionine supplementation of diets based on wheat products and meatmeal has been investigated. The effects of 0.025, 0.05, and 0.20 per cent. methionine on growth and feed efficiency were studied on White Leghorn chickens up to 6 weeks of age. It was concluded that maximum dose response occurred between 0.05 and 0.20 per cent. supplement. Under simulated commercial conditions, comparisons were made between WL x AO and AO x WL cockerels fed high and low energy diets unsupplemented or supplemented with 0.1 per cent. methionine to 8 weeks of age, or 0.1 per cent. methionine to 12 weeks of age. Neither methionine supplement produced a significant improvement in body weight when the low energy diet was fed. Both methionine supplements produced significant improvements in weight when the high energy diet was fed. In both diets methionine continuously produced highly significant improvements in feed efficiency, while methionine only to 8 weeks produced a significant improvement in efficiency only in the high energy diet. There was no difference between reciprocal crosses in weight or feed efficiency.
Flower initiation in Trifolium subterraneum L. II. Limitations by vernalization, low temperatures, and photoperiod, in the field at Canberra
Authors: Morley FHW , Evans LT
Published: November 2004

At various times throughout the winter, autumn-sown plants of five strains of subterranean clover were removed from the field to a series of day length and temperature treatments. The times to inflorescence initiation in all treatments were determined by dissection. As vernalization proceeded the requirement of all strains for long days was progressively reduced until, by midwinter, several strains had become virtually independent of day length. Similarly, with the progress of vernalization the inhibitory effects of high temperatures during short days became progressively less marked. Whereas exposure to long days at high temperatures greatly accelerated inflorescence initiation in all strains, long days at low field temperatures had little effect. Evidence is presented which suggests that the limiting effect of very low temperatures on initiation is due not only to retardation of the rate of inflorescence primordium formation (realization), but also to limitation of an inductive process other than vernalization and dark period inhibition. The flowering behaviour of the various strains is discussed in terms of their responses to the partial processes leading to inflorescence initiation, and the interrelationships of these processes are considered.
Trace elements in some South Australian terra rossa and rendzina soils
Authors: McKenzie RM
Published: November 2004

The concentrations of cobalt, zirconium, nickel, copper, vanadium, molybdenrun, manganese, and zinc have been determined in 10 profiles of terra rossas and 9 of rendzinas from South Australia. The soils from the lower south-eastern part of the State contain lower concentrations of all these elements than do those near Adelaide, particularly for cobalt, copper, and zinc. This difference is reflected in the concentrations found in the underlying calcareous material, and can account for the widespread deficiencies in cobalt and copper which occur ill the South-East.
Studies of the effects of the gene N on body growth and fleece development of the New Zealand Romney. II. The development of the fibre population
Authors: Cockrem F , Rae AL
Published: November 2004

An investigation of factors affecting fleece density in the N-type and ordinary Romney lamb is reported. The number of fibres per sq. centimetre on the loin position were estimated at birth, at 6 weeks of age, and at an average age of 24 weeks. At birth N/ + lambs had a lower fibre density than +/ + lambs and a high density of halo-hairs was associated with a lower density of other fibres. From birth to 6 weeks N/+ lambs added more fibres to the fleece than did +/ + lambs. In addition more fibres were added by lambs of both genotypes showing better body growth. For lambs showing poor body growth a high density at birth was associated with less new fibres at 6 weeks. Fibre density at 24 weeks was slightly but significantly lower for the N/+ lambs and, for both genotypes, was related to the 6-week density but not to the intervening body growth. The possible factors underlying these results are discussed.
Studies of the effects of the gene N on body growth and fleece development of the New Zealand Romney. IV. Fleece weight differences and general discussion
Authors: Cockrem F , Rae AL
Published: November 2004

Results are presented on the fleece weights of AT-type and ordinary Romney lambs and 18-month-old ewes. The A'-type animals had a higher greasy fleece weight when differences in body weight were corrected for. The remainder of the paper is concerned with discussion of the results of the previous three papers in terms of pleiotropy of the gene A' and of their implications in the interpretation of fleece development.
Parasitic gastro-enteritis and its effect on the blood and liver copper levels of dairy calves
Authors: Bremner KC
Published: November 2004

Experiments were performed to determine the effect of parasitic gastroenteritis on copper levels in the blood and liver of Australian Illawarra Shorthorn dairy calves. In two trials with calves heavily infested with Haemonchus placeii (Place) Ransom, Bunostomum phlebotomum Railliet, Oesophagostomum radiatum (Rudolphi), and CooperiaA spp., severe anaemia and hypoproteinaemia resulted. Liver copper levels of the infested calves were depressed, n-hereas those of wormfree controls either rose or remained relatively constant. The degree of depression appeared to be related to the magnitude of infestations. While slight falls in liver copper levels of worm-free calves could be induced by daily withdrawal of large volumes of blood, these falls were not of the same magnitude as those produced by trichostrongyle parasites. In a third experiment calves were infested with B. phlebotomum only, and it was demonstrated that following the administration of a known amount of copper sulphate by ruminal injection, significantly less copper was taken up and stored in the liver by parasitized calves than by worm-free controls. Indications were obtained that whole blood and plasma copper levels mere depressed by infestations in which B. phlebotomum predominated, but plasma copper concentrations were unaffected by chronic phlebotomy or by heavy infestations in which H. placei predominated. It was found necessary to withdraw a total of 27.5 I. of blood over a period of 19 weeks from worm-free calves in order to produce changes in their haemoglobin levels similar to those shown by calves carrying heavy mixed infestations consisting of H. placei, B. phlebotomum, O. radiatum, and Cooperia spp.
Annual pattern of soil moisture stress under sown and native pastures
Authors: Begg JE
Published: November 2004

Soil moisture fluctuations were measured under a phalaris-white clover pasture and under three native pasture types in the New England region of New South Wales over a 4-year period, by means of the gypsum resistance block technique. The results indicate that large differences in available soil moisture occur at times within areas of apparently similar soil type and that these differences are reflected by the different pasture types in the area. Although the lengths of the period during which soil moisture was unavailable differed considerably under the different pastures the general pattern was similar. The months of greatest soil moisture stress were December, January, April, and May, while the period of most favourable soil moisture was from June to November. Thus although most of the rain fell during the period December to May the rain which fell from June to November was more effective in maintaining available soil moisture. The subsoil dried out more rapidly and remained dry for a longer period under the sown pasture than under the native pasture type which the area previously carried, owing to the greater rate of removal of available soil moisture from under the sown pasture. Of the three native pasture types studied, the most favourable soil moisture pattern for plant growth occurred under the Sorghum-Themeda pasture. This pasture type may be a useful indicator of areas with soil conditions favourable for the growth of productive sown pastures.
Grazing management of native pastures in the New England region of New South Wales. I. Pasture and sheep production with special reference to systems of grazing and internal parasites
Authors: Roe R , Southcott WH , Turner HN
Published: November 2004

In a 4-year grazing experiment with Merino sheep, on a native pasture dominated by Bothriochloa ambigua S.T. Blake, three rates of stocking and continuous v. rotational grazing were compared. The effects of these treatments on the forage available and the botanical composition of the pasture and on sheep liveweights, size of sheep, wool production, wool fibre diameter, and parasitic infestation, both with and without drenching with phenothiazine, mere studied. The effects of seasonal conditions on the above and on the chemical composition of the pasture were also recorded. No consistently significant differences between grazing treatments in their effects on the pasture or on sheep liveweights or parasitic infestation were recorded, although during the final 3 years the total forage available was less under heavy stocking. Seasonal variations in total forage mere not marked, but, production of green forage increased greatly in the spring and declined to a very low level during winter. Similarly, sheep liveweights increased during spring and summer and declined in the winter. These liveweight changes were significantly correlated with the amount of green forage available. Wool fibre diameter showed similar seasonal fluctuations but the maximum diameter was attained earlier than maximum liveweight. Coincident with a spring rise in the amount of green forage there was also an increase in the percentages of crude protein and phosphorus in the green components of the pasture. Liveweight gains of the drenched sheep were significantly greater from the beginning of each experimental year in the late spring (November) to late winter (August) in all stocking treatments. In the spring, when the quality of the pasture improved and worm egg counts were low, drenching had no effect on liveweight gains in three out of four years. Drenching also significantly improved wool production and resulted in an increase in skeletal size of sheep in three out of four years. Drenching reduced egg counts of the parasites Oesophagostomum spp. and Haemonchus contortus (Rudolphi) Cobb but was less effective against Trichostrongylus-Ostertagia spp. For all grazing treatments there was no significant difference in the amount of wool produced per head, but over the 4-year period 56 per cent. more wool per acre was produced from the heavy than from the light rate of stocking.
Studies on the reactions of animals to infestation with ticks. IV. The protein components of tick extracts
Authors: Riek RF
Published: November 2004

Filter-paper and starch electrophoresis and gel diffusion have been used to separate and identify the various protein components of tick extracts. Changes in the relative protein composition with increasing age of the eggs and larvae of Boophilus microplus (Canestrini) were revealed on filter paper electrophoresis. Toxicity of laboratory animals was due on most occasions to three fractions, F1, F2, and F6, in the egg extract, but to only one fraction, F2–3, in the larval extract. On a few occasions the a-globulin, F6 (haemixodovin), was non-toxic. The reason for the apparent variation in toxicity of this fraction is not understood. Toxicity decreased with age of both eggs and larvae, 14-day-old larvae being relatively non-toxic. Reactions of identity revealed the presence of similar or closely related components in the egg and larval extracts. Immunization with larval extracts prevented the toxic effects of the egg extracts. The antigen largely responsible for the development of skin hypersensitivity, F1, was also one of the toxic components. It was a y-globulin and had the greatest mobility of the y-globulins under these specified electrophoretic conditions. Skin-sensitizing activity was also shown by fraction F2, and to a lesser degree by F3. This may have been due to incomplete separation of the individual components.
The control of seed germination by moisture as a soil physical property
Authors: Collis-George N , Sands JE
Published: November 2004

The germination (i.e. the first emergence of the radicle) of Medicago denticulata Willd., M. confinis Koch, M. tribuloides Desr., and Juncus vaginatus R. Br. under controlled moisture conditions has been examined. Moisture regime was defined by the soil moisture suction (pF). The influences of temperature and light, which would otherwise obscure the importance of soil moisture, have been minimized by comparing the number of seeds germinated under each physical regime with the maximum number germinated for each species under identical physical conditions when suction was approximately zero (i.e. standard cotton wool germination count procedure). The differing water regimes were obtained by using methods common in soil physics – the tension plate and pressure membrane methods – the seeds being in contact with the plate or membrane kept at a constant water suction. Additionally, two soil media, were used with the Medicago spp. It was found that:

For all species an increase in suction produced a decrease in rate of germination until at 10 atm, germination practically ceased.

Medicago spp. showed a smaller decline in rate as suction increased than did J. vaginatus.

The moisture conditions to allow J. vaginatus to germinate at rates comparable with those for the Medicago spp. were quite restricted and corresponded to high water-tables or soils wetter than field capacity.

The moisture condition of the soils controlled the germination rate not only by means of the suction effect, but also in terms of hydraulic conductivity (or permeability). A drier soil having less ability to transmit water than a wetter soil reduced the rate at which water could reach the seed, with a consequent decline in the germination rate.

As the relationships between: (a) moisture content and suction, and (b) moisture content and hydraulic conductivity, are soil characteristics, it is necessary to define the soil moisture characteristic as well as moisture content in germination experiments.
The role of calcium and magnesium in the nutrition of Rhizobium
Authors: Norris DO
Published: November 2004

A critical examination was made of the calcium nutrition of Rhizobium, a large number of strains being selected to represent a fair cross section of Leguminosae. Growth was examined in colloidal clay suspensions, in liquid yeast-extract mannitol medium, in a synthetic liquid medium specially purified of calcium, in tubes of krasnozem soil, and on nutrient agar slopes. Effects on symbiotic behaviour were assessed by periodic testing on suitable host species. It is concluded that Rhizobium is not a calcium-sensitive organism. If it has any calcium need it must be of a secondary nature, satisfied by minute trace amounts of the element. On the other hand it is shown that Rhizobium has an essential need for magnesium. Apparent growth responses to calcium when grown on colloidal clays are actually responses to magnesium made available by cation exchange. Growth of many slow-growing types is improved by omitting calcium compounds from agar culture media and enhancing magnesium supply. The significance of these findings to the growth and maintenance of cultures, to the solution of field nodulation problems, and to the evolutionary history of the symbiosis is discussed.
Leaf structure in relation to quality in flue-cured tobacco
Authors: Barnard C
Published: November 2004

The morphology and anatomy of flue-cured tobacco leaf are described and efforts made to relate the structural features of the leaf to the indices used by the tobacco trade in assessing leaf quality. There is a close relationship between the anatomy and morphology of the leaf and its position on the stalk. Assessor's indices are also closely associated with leaf position. Thickness and weight per unit area of leaf are measures of "body", while cell size and compactness of cell arrangement are the physical basis of "grain". "Elasticity" is not related to any particular anatomical or morphological characters; it is associated with some water-soluble constituent or constituents of the leaf, which enable the leaf to remain pliable at low moisture contents. "Lustre" also is not related to any structural features. Indirect evidence suggests that "lustre" is an indicator of chemical composition. "Body" and "grain" of the cured leaf might be forecast from the anatomical structure of the green leaf, but "elasticity" and "lustre" could not be forecast.
Soil sulphate changes in the presence and absence of growing plants
Authors: Freney JR , Spencer K
Published: November 2004

To determine whether sulphate addition to sulphur-deficient soils affects mineralization of organic sulphur, an experiment was conducted in undrained pots with five soils of differing properties. Initial and final extractable soil sulphate (water-soluble and adsorbed), and sulphur taken up by Phalaris tuberosa L., were measured. Where plants were grown, mobilization of the organic sulphur occurred at the nil, 4 p.p.m., 12 p.p.m., and 36 p.p.m. levels of sulphate sulphur addition in four out of the five soils. In the fifth soil, a lateritic krasnozem, only at the nil and 4 p.p.m. levels was there any net release of sulphate. All five soils immobilized added sulphate at the 108 p.p.m. level. In the absence of plants, with one exception, no net mineralization of organic sulphur occurred following additions of sulphate. In the pots without added sulphate there was slight mineralization (less than under plants) in all soils but the lateritic krasnozem. The modifying effect of growing plants is obviously of great significance in the cycling of sulphur in soil. The relative intensity of immobilization and mineralization was affected by the presence of growing plants. This effect was probably due to the activities of rhizosphere microorganisms.
Hornedness and polledness in sheep. I. The inheritance of polledness in the Merino
Authors: Dolling CHS
Published: November 2004

Twenty-five polled Merino rams were mated singly to either polled or horned Merino ewes, the horned ewes having either bone knobs or short scum on their horn sites. All parents and offspring were horn-scored with the aid of a detailed classification system suitable for defining all types of horn sites encountered in the Merino. Polledness is dominant to hornedness and results from the action of an autosomal dominant gene, P. The recessive allele, p, in homozygous form results in true horns in the male and bone knobs or short sours in the female. The inheritance of horns in the female is discussed in a later paper. Details are given of the phenotypic differences between PP and Pp rams, which are important in the selection of poll Merino rams. There is some overlap between the phenotypic ranges of these two genotypes.
Drought feeding of cattle. I. Comparison of hay-grain and all-grain rations: with observations on vitamin A status
Authors: Southcott WH , McClymont GL
Published: November 2004

Yearling Hereford steers in store condition (average weight 585 lb) were fed whole wheat grain, or equal parts whole wheat grain and cereal hay, each diet supplying an estimated 2 lb of starch equivalent per head per day. After the different rations had been fed for 20 weeks, followed by hay-grain rations for 1 week to equalize gastro-intestinal fill, the cattle fed an all-grain ration had lost an average of 1.03 lb per day and those fed a hay-grain ration had lost 0.84 lb per day. The final difference in weight was not significant. All cattle remained in good health. Serum vitamin A levels declined during the experiment to subnormal levels, particularly in the all-grain group, but clinical signs of vitamin A deficiency ware not evident. Coprophagia, hair chewing, and biting of woodwork were observed, particularly in the all-grain group. It is concluded that all-grain rations may be satisfactorily used for drought feeding of cattle.
The availability of potassium in some Tasmanian soils. II. Exhaustive cropping in relation to potassium reserves in the soil
Authors: Piper CS , de Vries MPC
Published: November 2004

Five soil samples from Fingal, Tas., representing Frodsley sandy loam of varying exchangeable potassium status, were subjected to exhaustive cropping in pots and the changes in their potassium status and that of the crops measured. Three of the samples represented an area carrying improved pastures while two were from a less intensively managed property. The results were contrasted with those from two soils from South Australia (Urrbrae loam and Seddon gravelly sandy loam). The progressive removal of potassium by cropping was determined by analysis of each crop and of the soil at the end of the experiment. Uptake and removal of potassium was greatest from the soils of highest exchangeable potassium status. Potassium applied to the soils was also rapidly taken up by the crops. For the Tasmanian soils, applications of potassium gave no responses in yield until the level of exchangeable potassium in the control pots fell to 0.10-0.15 m-equiv./100 g. The higher the initial level of exchangeable potassium, the greater the number of crops before a yield response to applied potassium was obtained. In contrast, yields were maintained at a high level on Urrbrae loam and, even in the fourth crop, applications of potassium gave only a barely significant response. From Frodsley and Seddon soils only small amounts of potassium were taken up from non-exchangeable sources. From Urrbrae loam, in the absence of applied potassium, slightly more than half of the potassium taken up by the crops was derived from other than exchangeable sources. These differences were in keeping with the different amounts of potassium released to boiling nitric acid by these soils. After four crops exchangeable potassium was reduced to very low levels (0.05-0.14 m-equiv./100 g) in all five Tasmanian soils. These values were directly related to the amounts of difficultly exchangeable potassium in these soils. Exchangeable potassium in Urrbrae loam was not reduced below 0.33 m-equiv./100 g, again reflecting the higher reserve of difficultly exchangeable potassium in the illitic clay of this soil and its greater capacity to replenish the exchangeable potassium fraction. The percentage of potassium in the dry matter of the crop was closely related to the level of exchangeable potassium or exchangeable plus added potassium in the soil. Subterranean clover showing severe leaf necrosis due to potassium deficiency contained 0.55-0.63 per cent. potassium. Plants showing less severe deficiency symptoms or symptoms developing at a later stage showed 0.84-0.98 per cent. potassium. Plants with 1.20 per cent. potassium were free from symptoms and gave no further yield responses to applied potassium. Additions of potassium to the soil led to higher values in the plants, and luxury uptake was common. At least 84-95 per cent. of the applied potassium was taken up by the crops on four of the Tasmanian soils.
Water balance and the water-table in deep sandy soils of the upper south-east, South Australia
Authors: Holmes JW
Published: November 2004

A water-table occurs at an average depth of 11.3 m below the surface in deep sand country of the upper south-east of South Australia (County Cardwell). By observing the depth to which water penetrated into the soil profile during the wet season, and the static level of the water in bore-holes, it was proved that the watertable was not replenished by local rainfall. In three years of records, the wetting front penetrated 6.0, 2.1, and 3.6 m on the average, and the soil water thus stored was all used by the prevailing vegetation, either natural mallee heath or lucerne. The performance of the vegetation growing on the deep sand in ability to resist drought was characterized quantitatively by the supply rate of soil moisture as a function of the soil water storage. It was estimated that the yearly potential evaporation for 1957 was 113 cm. The mean annual rainfall is about 50 cm. The ground-water comes, it is suggested, from intake areas about 40 km east of the area under study, where surface floodwaters accumulate in wet seasons. The quantity of water flowing through the aquifer at present is calculated to be about 37 m3/(metre width of strip)/year.
Comparative responses to calcium of five tropical and four temperate pasture legume species
Authors: Andrew CS , Norris DO
Published: November 2004

A low humic grey soil grossly deficient in calcium was used to ascertain the relative effects of calcium carbonate additions on the growth, calcium and nitrogen contents, nodulation, and calcium deficiency symptoms of five tropical legumes (Desmodium uncinatum (Jacq.) DC., Indigofera spicata Forsk., Centrosema pubescens Benth., Stylosanthes bojeri Vog., and Phaseolus lathyroides L.) and four temperate legumes (Medicago tribuloides Desr., M. sativa L., Trifolium fragiferum L., and T. repens L.). In the absence of added calcium the five tropical legumes did not show any visual symptoms of calcium deficiency, and the respective yields on the nil treatments were 25, 40, 52, 64, and 68% of their maximum yields in the presence of added calcium carbonate. The four temperate legumes showed visual symptoms of calcium deficiency. and the respective yields on the nil treatments were 0.2, 1.5, 2.0 and 6.5% of their maxima. Calcium, nitrogen, and nodulation data are quoted and discussed. It is considered that the effect of added calcium carbonate in this soil is primarily one of calcium nutrition of the species, and that the differences between the two groups of legumes may be due to restricted uptake. There is evidence that the process of nodule formation is calcium-sensitive in the tropical species as well as in the temperate species. It is suggested that the superior ability of the tropical species to nodulate at low calcium levels is primarily related to their superior ability to extract calcium from the soil.
Suppression of oestrus in sheep with progesterone
Authors: Lamond DR , Lambourne LJ
Published: November 2004

Progesterone in oil was given intramuscularly to groups of Merino ewes during the autumn breeding season in order to test various dosage levels and injection intervals for suppression of oestrus. Mean daily doses were 5, 10, or 20 mg. given either daily, or as a double dose every second day, or as a quadruple dose every fourth day. The follovving results were obtained: Injections daily or every 2 days suppressed oestrus in most ewes. Injections every 4 days were less successful. There was a significant tendency for ewes in late cycle at the time of the first injection to come into oestrus at their expected date.The intervals between the last injection and oestrus for the 5 mg mean daily dose were 1.6 days (daily injection) and 2.0 days (injection every 2 days); for the 10 mg dose 2.3 and 2.6 days; and for the 20 mg dose 3.8 and 4.4 days. Of 19 ewes which mated during the injection period only one lambed. Fertility in ewes mated after the injection period was greatest in those given injections of progesterone every 2 days.
Soil fertility changes in the long-term experimental plots at Kybybolite, South Australia. III. Changes in cation exchange capacity and exchangeable cations
Authors: Russell JS
Published: November 2004

Changes in the cation exchange complex are one of the secondary effects arising out of the increasing organic matter content of soils, due to the influence of phosphorus fertilizers on leguminous pastures. Analysis of solonetzic soils from the long-term Kybybolite P plots indicates that there is a close relation between organic matter increase and increases in cation exchange capacity. For each increase of 0.1 % soil nitrogen, there has been a corresponding increase of 3.48 m-equiv.jl00 g in cation exchange capacity. Associated with these changes there have been increases in the level of exchangeable calcium and exchangeable hydrogen. Changes in exchangeable calcium appear related to the amount and form of fertilizer or amendment applied. Where little calcium has been added, the increase in cation exchange capacity has been satisfied almost entirely by hydrogen, and base saturation has decreased. There appears to have been little upward movement of metal cations from the lower horizons to the surface by plants, possibly owing to the species involved, or to the intractable nature of the B horizon. The possible effects of changes in the cation exchange complex on plant growth are discussed. Also, the possibility of maintaining base saturation on infertile soils where cation exchange capacity is being increased, is examined.
Flower initiation in relation to maturity in crop plants. I. Flower initiation in relation to maturity in some Australian oats (Avena spp.)
Authors: Aitken Y
Published: November 2004

The description of oat varieties as early, mid, and late depends mainly on differences in their time of flower initiation. Flower initiation has been studied in varieties grown in southern Australia and ranging in maturity from first early to late. The time to flower initiation was found to depend greatly on the variety�s response to photoperiod and temperature. In all groups but the first early one, initiation was hastened by lengthening photoperiod and reducing temperature. The later the variety, the greater was the effect. Early varieties are those in which initiation occurs at a low leaf number over a wide range of photoperiods and temperatures. Late varieties result from initiation at a high leaf number, the delay compared with early varieties being due to sensitivity to high temperatures and to short photoperiods. These are the conditions prevailing after late summer and autumn sowings. Late varieties mature early in the field when grown either at low temperatures (below 50�F), or at slightly higher temperatures (below 60�F) and intermediate photoperiod. This is similar to the reaction of variety Clare in the second early group of' subterranean clover. Very late varieties of oats, similar to winter wheats which have a pronounced cold requirement for initiation, are not yet present in Australia.
Influence of fertilizer treatment on apple fruit composition and physiology. 1. Influence on cell size and cell number.
Authors: Letham DS
Published: November 2004

Cell size and cell number in Sturmer Pippin apple fruits from trees receiving different fertilizer treatments have been determined. N fruit contained larger cells than U, P, NP, or NPK fruit of the same weight (K = 2 lb sulphate of ammonia, P = 4 lb superphosphate, and K = 1 lb sulphate of potash per tree per year: U = no fertilizer). Fruit from the latter four treatments did not show any consistent differences in cell size. In fruit of the average size for each treatment, differences in cell number per fruit were present,, N fruit containing fewer and larger cells than fruit from all other treatments. Cell number of NPK fruit was greater than that of U fruit. Mean cell volumes for fruit from the various treatments were significantly correlated with the incidences of internal breakdown in storage in each of three years. IS fruit of varieties Cox's Orange Pippin and Dunn's Favourite contained larger cells than U or SPK fruit of the same size. Delicious SPK fruit contained smaller cells than U or IS fruit), the cell sizes of which did not differ.
Control of superficial scald on Granny Smith apples with diphenylamine
Authors: Hall EG , Scott KJ , Coote GG
Published: November 2004

The preliminary work of Smock (1955) indicated that treatment of apples with diphenylamine (DPA) offered a promising new method of controlling superficial scald on cool-stored apples. The effect of DPA and various methods of application hare been widely studied under Australian conditions over five seasons, Granny Smith apples grom-n in New South Wales being used. Treatment of fruit with a suitable concentration of DPA prevented the development of scald on fruit cool-stored in air, in controlled atmospheres, and in polyethylene film box liners, even when scald was severe and not controlled by oiled wraps. DPA was successfully applied to the fruit by impregnating it into standard paper wraps, by post-harvest dipping, and by pre-harvest spraying. It was found that there was a quantitative relation between the severity of scald and the concentration of DPA required to control it. DPA was shown to have a very limited mobility in the fruit. Residues in the fruit were related to both the amount applied and the method of application, and in all cases were low after cool storage. DPA appears to have a sufficiently low phytotoxicity for use as a pre-harvest spray. Its human toxicity is still under investigation. If approved for use on apples it will probably be in a purified form.
Factors affecting the survival and dissemination of Mycosphaerella pinodes (Berk & Blox) vestergr. in South Australian irrigated pea fields
Authors: Carter MV , Moller WJ
Published: November 2004

Results of trapping M. pinodes ascospores with a Hirst volumetric spore Trap during two successive crop seasons have demonstrated the pattern of variation of airborne inoculum in a South Australian irrigated pea field. Ascospore concentrations in the air above the field can be related to the presence of mature perithecia in residual crop debris and to the maturation of new perithecia on plants of the current crop. Wind tunnel experiments have shown that approximately 0.007 in. rainfall is the minimum for ascospore release, and that the peak liberation from mature perithecia occurred within 0 . 5 hr of wetting the straw. Results of experiments with straw burial treatments indicated that soil temperatures in the range 28–33°C, with high moisture, will cause a rapid reduction in the numbers of ascospores which may be discharged when the straw is unearthed subsequently. Examination of perithecia in straw which no longer discharged ascospores after such treatments, however, revealed that the perithecia, contained masses of dark-coloured spores quite distinct from normal ascospores.
The use of rumen material in culture media for rumen bacteria
Authors: Munch-Petersen E , Boundy CAP
Published: November 2004

The suggestion that homologous rumen fluid in culture media results in better growth of rumen bacteria than that obtained with heterologous fluid was tested with samples of rumen material from cows and sheep, with the use of rumen fluid from cows and sheep, and two agar culture media. It is shown that the suggestion cannot be taken as applying in general. With rumen material from the cow, the use of either type of rumen fluid gave the same growth, whereas with rumen material from the sheep, growth was depressed by use of sheep rumen fluid.