bluuebunny/crossref_metadata_2025 huggingface dataset:
A study of the development of dieldrin-resistance in relation to acaricide pressure in a population of Boophilus microplus
Authors: Roulston WJ
Published: November 2004

Dieldrin and aldrin preparations were used on separate properties where only arsenic had been used previously for tick control. Tick stocks from the properties before the commencement of the experiment showed no acaricide resistance. Dipping in dieldrin commenced on one property in November, and satisfactory control was obtained with the first three dippings at approximately 6-week intervals. After the fourth dipping, in late March, however, there was a marked survival of all stages of ticks, but particularly adults, although the vat concentration of dieldrin was almost as high as formerly and the deposits of the toxicant on the hair of the cattle were heavier. Progeny of female ticks which survived the fourth dipping were shown in laboratory tests to be highly resistant to dieldrin. Ticks present on the cattle at the fourth dipping could have included descendants of tick stocks which had undergone a maximum of four challenges with dieldrin, though most would have experienced only two to three. The fifth dipping was more effective than the fourth, which suggested irregular distribution of the dieldrin-resistant ticks in the pastures, possibly associated with periodical changes in the grazing of the cattle. The ticks present at the sixth dipping were highly resistant to dieldrin, and there was no protective period. Ticks from a culture established about 8 months after the inception of dipping were more than 900 times as resistant to dieldrin as the reference culture when tested by immersion. On another property a poor kill resulted from an initial dipping in 0.05% aldrin in early February, but high kills resulted from dippings in 0.10% aldrin in early March and early April. The tolerance of the ticks to aldrin after the conclusion of the experimental programme of five dippings was no higher than before its commencement. This could have been due to the fact that the reproducing populations of the tick received less severe and less frequent selection with the acaricide than during the course of the dieldrin trial. However, satisfactory results were still obtained by the owner with aldrin during the following tick season, and it is more likely that the contrasting results on the two properties were due to the presence of the resistance gene on the one property and its absence on the other.
Wether bioassay of annual pasture legumes. I. Oestrogenic activity in Medicago tribuloides Desr. var. Cyprus* relative to four strains of Trifolium subterraneum L.
Authors: Millington AJ , Francis CM , McKeown NR
Published: November 2004

The grazing of pasture swards of Cyprus barrel medic and of four strains of subterranean clover resulted in increases of wether teat length similar to those produced by injections of a synthetic oestrogen, diethylstilboestrol. Oestrogenic activity of the medic, as measured by increase in wether teat length, was less than that of the Yarloop and Dwalganup strains of subterranean clover, but similar to that of the Mt. Barker strain. Coumestrol appears to be the principal oestrogenic substance in the medic. The coumestrol contents of Cyprus and commercial barrel medics were similar but varied at different localities. The low coumestrol content of the subterranean clovers suggests that it is not an important oestrogen in this species.
____________________

*Cyprus barrel medic. During the joint FAO–CSIRO collecting expedition in 1950–1951, J. F. Miles collected barrel medic, C.P.J. 13914, in Cyprus, and portion of the seed was passed to D. Symon at the Waite Agricultural Research Institute, Adelaide.
A programme, commenced in 1950, to extend the legume belt into the lower rainfall districts
of Western Australia, indicated the need for an earlier-flowering medic, and Symon suggested testing the Cyprus introductjon.
Encouraging results from sward tnals conducted by the Institute of Agriculture, University of Western Australia, resulted in a programme of seed increase and large-scale commercial production of the Cyprus strain. The Cyprus strain flowers 4 weeks earlier than the commercial and 5 weeks before M. tr ibuloides 173, and is proving a very satisfactory legume on a wide range of soils in Western Australia.
Wether bioassay of animal pasture legumes. II. The oestrogenic activity of nine strains of Trifolium subterraneum L.
Authors: Millington AJ , Francis CM , McKeown NR
Published: November 2004

Nine strains of subterranean clover (Trifolium subterraneum L.) were assayed for oestrogenic activity with changes in wether teat length as the criterion. The isoflavone and coumestrol contents of each strain were determined by thin-layer chromatography. Significant differences were obtained between strains. Multiple regression analysis indicated a positive relationship between increase in teat length and the formononetin content of the strains. No such relationship was found for either genistein or biochanin A, the other isoflavones that were present in appreciable amounts.
The effect of nutritional regimen on the potential semen production of rams
Authors: Salamon S
Published: November 2004

(1) Six mature grazing Merino rams were given either a low (LP) or high (HP) level of supplementary feeding for 6 weeks before being subjected to a period of intensive semen collection every 15 weeks for 18 months (six collection periods). At each collection period 16 opportunities for ejaculation were given daily to each ram over two series of 5 days, separated by 2 days' rest. Each ram was exposed to three LP and three HP pre-collection periods. Ejaculates were examined for semen characteristics and the 'reaction time' was recorded at each service. (2) The average daily sperm output for the six rams was 10.8 x l09. There were no significant differences between rams. (3) The high level of supplementary feeding (600 g total digestible nutrients (T.D.N.), 165 g crude protein per day) had a significant influence on sperm production as compared with a low level (310 g T.D.N., 45 g crude protein per day). The daily sperm output averaged 12.7 x 109 for the HP group and 8.8 x l09 for the LP group (P < 0.001). (4) There was no significant effect of month of collection on total sperm production, although there was an effect on density. The percentage of abnormal sperm did vary significantly (P < 0.001), and was highest (12.2%) in January (midsummer). Motility was generally good (mean 4.4 out of 5). Apparently significant differences emerged from the analysis, but are of doubtful biological significance in view of the relatively small absolute difference. (5) Sperm output showed an asymptotic decline in the two successive weeks of each series of collection and on successive days within weeks (P < 0.001). (6) There were significant differences between month of collection in sexual drive (number of ejaculates and reaction time, P < 0.001). It was most intense during autumn (April). (7) There were significant differences between rams in sexual drive (P < 0.001). Sperm output of individual rams was not influenced remarkably by the number of ejaculates within the range of 130–160 over two 5-day series.
Stimulation of wool growth by thyroxine implantation. II. Feed intake of grazing Merino wethers treated repeatedly with thyroxine.
Authors: Lambourne LJ
Published: November 2004

Estimates have been made of the feed intake of wethers that received implantations of 60 mg thyroxine every 3 months, and of untreated sheep, grazing together. The estimated intake of digestible organic matter (D.O.M.) by treated wethers was higher than that of controls in 24 out of 27 measurement periods. The difference in feed intake was least in the iirst month after implantation, when the treated sheep lost weight, and greatest in the second and third months when the treated sheep were regaining weight. The overall increase in intake resulting from thyroxine treatment (20–25%) was greater than the increase in wool production (7% greasy weight, 3-7 % clean weight), and the efficiency of wool production was therefore lower in thyroxinetreated wethers. From the relationships between feed intake and rate of weight change it was concluded that in the month after implantation, when pulse rates indicated a substantial rise in metabolic rate, the maintenance feed requirement was raised from about 560 g to about 780 g D.O.M. per day. Observations in two winters with recently shorn sheep gave estimates of maintenance requirements for untreated wethers ranging from 850 to 1300 g D.O.M. per day. During recovery from repeated thyroxine implantation the wethers gained in weight no more efficiently than the controls. The mechanism of action of exogenous thyroxine is discussed in the light of these and other data.
Dormancy and hard-seededness in Western Australian serradella (Ornithopus compressus L.)
Authors: Barrett-Lennard RA , Gladstones JS
Published: November 2004

Experiments were carried out to test the effects of harvesting date, relative humidity in storage, alternating high and low storage temperatures, and hulling and scarification on seed permeability, dormancy, and viability in Western Australian serradella (Ornithopus compressus L.). Hard-seededness (permeability) was found to be governed by seed moisture content. At storage humidities of 76% R.H. and more, all initially soft seeds remained soft, while at 44% R.H. or less and in the open laboratory, all seeds became fully hard. Storage at 52 and 66% R.H. resulted in semi-hardness and delayed germination. Seed maturity did not influence the degree of hardness attained. Seeds in the field became impermeable as soon as they were mature. Breakdown of impermeability occurred either naturally in the field or in storage under alternating temperatures simulating the summer temperature range at the soil surface, but not in storage at a constant temperature of 20°C. The presence of husks surrounding the seeds had no appreciable effect on permeability. The viability of soft seeds was impaired after 7 months' storage at R.H. levels of 76% and over and a constant temperature of 20°C. Hard-seededness gave complete protection against the injurious effects of these conditions. Loss of viability of the soft seeds was not related to their maturity within the range of maturities tested. No physiological dormancy was observed in the seeds themselves, but unhulled seeds (i.e. those not threshed out of the pod segments) tended to remain dormant, which suggested the presence of a water-soluble germination-inhibiting substance in the husks. This dormancy broke down in mature pod segments under alternating high and low temperatures, but not in immature segments or at a constant temperature of 20°C. Recommendations are made for improving the germination of commercial Western Australian serradella seed.
The relation between weather and fruitfulness of the sultana vine
Authors: Baldwin JG
Published: November 2004

The percentage of fruitful buds on sultanas is shown to be closely related to the weather over 3 weeks in late November and early December mdash; that is, during the period when the inflorescence primordia are differentiated. The two factors concerned are the hours of bright sunshine and the sum of daily maximum temperatures from 82 to 90°F. An estimate of the start of the period for which these weather elements are effective can be made by summing mean temperatures from bud burst. The study covers 18 years, 1945 to 1962 inclusive. Fruitfulness was lower than expected in the first 9 years, and higher in the second 9 years, possibly because of the use of Bordeaux spray in the first period and its replacement by organic sprays in the second. Fruitfulness can be forecast within practical confidence limits from a regression developed for fruitfulness from 1954 to 1962 inclusive on sunshine and maximum temperatures.
The effect of temperature stress on grain development in wheat
Authors: Asana RD , Williams RF
Published: November 2004

Experiments were conducted in controlled environments to determine the effects of high temperatures on grain development and yield in wheat. Two Australian and three Indian cultivars of wheat were exposed, from a week after anthesis until maturity, to "day" temperatures of 25, 28, and 3l°C, and "night" temperatures of 9 and 12°C. There was a mean reduction in yield of 16%' for the 6° rise in day temperature, but the cultivars did not differ significantly in their response to these temperatures. There were no significant effects of night temperature on grain weight, but stem weight was less at 12°C. Senescence was hastened only slightly by high day temperature, and there were no differential effects between cultivars in this respect.In a subsidiary experiment one Indian and five Australian cultivars were subjected to three day-night temperature regimes (24/19°, 27/22°, and 30/25°C). Highly significant but complex interactions were established between temperature regime and cultivar. A growth analysis for the Australian cultivars Ridley and Diadem indicated that the developing grain of Ridley had a greater capacity for growth than that of Diadem from the earliest stage. This, together with the confirmation of grain size as a very stable characteristic for all the varieties, points to the developmental and synthetic activity of the grain as an important determinant of grain yield. The relevance of this study to the production of wheat in India is briefly discussed.
Nutritional evaluation of meat meals for poultry. IV. Prevention of growth depression from high levels of bone or calcium by vitamin and antibiotic supplementation
Authors: Sathe BS , McClymont GL
Published: November 2004

Experiments were conducted to determine the reason for depressed growth in chickens when high levels of bone, bone ash, or calcium were added to diets based on wheat, skim milk, and soybean and/or meat meal, and containing a basal supplement of vitamins and an antibiotic. The growth depression was not due to energy dilution of the diet, nor to an induced deficiency of essential fatty acids or minerals. The growth rates of pair-fed groups of chickens indicated that about half the growth depression was due to a reduced food intake. Depression of appetite and growth was completely prevented by further vitamin . plus antibiotic supplementation of diets containing added bone, bone ash, or calcium carbonate up to a total calcium content of c. 2.5%, but not when calcium exceeded this level. Additions of either vitamins or antibiotics alone produced responses but were not as effective as in combination.
The interrelation of susceptibility to breakdown, cell size, and nitrogen and phosphorus levels in Jonathan apple fruits
Authors: Martin D , Stenhouse NS , Lewis TL , Cerny J
Published: November 2004

A block of Jonathan apple trees were treated for 4 years as individual tree plots with nil, nitrogen, nitrogen + phosphorus, and nitrogen + potassium applied as sprays during two periods, either in spring before bud differentiation or after bud differentiation in mid January. The treatments had no effect on the levels of phosphorus or potassium in the fruit. Spring applications had no significant effect on the nitrogen content, but summer applications a marked one, though there was no evidence of a cumulative build-up or any effect on cell number per fruit. These increases in nitrogen content were accompanied by small increases in breakdown level, but only when an inherent seasonal susceptibility existed. Only a diminishing proportion of the additional nitrogen was incorporated into the protein fraction, and the preclimacteric respiration rate was not affected significantly by the increase in protein. Except for percentage dry matter, there was a wide variation in the values between trees of the variables, which permitted a multiple regression analysis. The regression of breakdown and cell volume was positive and highly significant in all years. Except for the year of very low incidence, there was a significant positive relationship between breakdown and nitrogen level, and a consistent negative relationship between breakdown and phosphorus level which was significant in the years of high breakdown incidence. No relationship could be shown between breakdown and potassium. Similar results were obtained by using a percentage fresh weight or percentage dry weight basis for the nitrogen, phosphorus, and potassium contents, or by using actual values or a log (x + 1) transformation for the variables, though there were some advantages in using the latter. The results suggest an important physiological interaction between breakdown and cell volume, nitrogen, and phosphorus.
Rumination in sheep. IV. The investigation of some possible control mechanisms
Authors: Pearce GR
Published: November 2004

Rumination of caged sheep was recorded under conditions of: (a) variable rumen pH, (b) rumen infusions of volatile fatty acids and urea, (c) variable saliva flow to the rumen, (d) mixing of the rumen contents in vivo, and (e) teasing with food. The circadian (24-hr) pattern of rumination after once daily feeding was similar to the pattern of rumen pH change, but no consistent effect of pH per se upon the initiation of rumination was found when rumen contents were replaced with buffered mixtures at pH values ranging from c. 5.10 to 6.95. Rumination, however, tended to be irregular at the lower pH levels. The addition of sodium carbonate to the rumen to prevent a fall in pH after feeding had no apparent effect upon the initiation of rumination. The infusion of volatile fatty acid or urea solutions into the rumen apparently did not affect rumination. Removal of part of the saliva by aspiration during eating, or adding previously aspirated saliva had no effect. The manual mixing of rumen contents by means of a large rumen fistula did not affect initiation of rumination. After teasing with food, one sheep did not recommence ruminating for several hours; another showed practically no reaction; and the remaining two intermediate responses. The initiation of rumination is discussed in relation to these and some other aspects.
Evapotranspiration of Safflower at three densities of sowing
Authors: Stern WR
Published: November 2004

In a low latitude environment, evapotranspiration from irrigated crops of safflower growing at low, middle, and high densities was determined from changes in soil water storage. Evapotranspiration was related to potential free water evaporation as calculated by the Penman formula. Except at the rosette stage and during the transition period leading to elongation, there was no measurable difference in evapotranspiration between densities. The ratio of evapotranspiration to free water evaporation was 1.57 during elongation and 1.25 between elongation and flowering, falling to less than 1 before the last irrigation and before any marked depletion of soil water in the root zone. Average evapotranspiration over the cropping period was 3.1 mm day-l and the transpiration ratio 342. Leaf area index and evapotranspiration rates were related by a Mitscherlich type curve with an evapotranspiration plateau of 4.2 mm day-1. The high ratios of evapotranspiration to potential evaporation were due to bulk advective conditions in this environment. The observed evapotranspiration is discussed in relation to the growth of the crop and the variations observed in the field.
Interactions between heredity and environment in the Australian Merino. III. Sire X Environment interactions
Authors: Dunlop AA , Young SSY
Published: November 2004

Interactions between sire and year (age), sire and drop (year), and sire and station in clean wool weight were estimated in data from five Merino strains at three stations. In general, interaction terms were small and non-significant, this being particularly so in the first two categories. Sire x station interactions were, in a few cases, of appreciable size. On the average the sire x station interaction component was approximately half as large as the component between sires. It was concluded that interaction will seldom appreciably hinder genetic progress from individual selection.
Studies on the immunity of sheep to Oesophagostomum columbianum: Proteins and haemagglutinatiog antibodies in mucous exudates and intestinal tissue extracts
Authors: Dobson C
Published: November 2004

A passive haemagglutination test utilizing formalinized, tanned, sensitized sheep erythrocytes was developed in order to study the antibody content of serum, mucus, and tissue extracts from sheep infested with Oesophagostomum columbianum. This test was compared with similar techniques developed by other workers for different helminth-host systems and was found to be more sensitive. The cells also retained their sensitivity as an antigenic suspension for a number of days. The haemagglutinating antibody titre of the serum was found to be consistently low: 1 : 3.3 in non-infested controls, 1 : 30 after a first, and 1 : 45.3 after a second infestation. Three extracts were made for each of nine separate sections of the alimentary tract: two 10 ft lengths of the small intestine anterior to the ileocaecal valve, one 2 ft length of the caecum and large colon, and six equal lengths of the colon through to the anus. These three extracts comprised a mucous exudate in saline, a saline homogenate of the mucosa, and a similar homogenate of the muscularis mucosae. The antibody titre of the mucous exudate was low in the controls but very high in the animals with first and second infestations compared with the titre obtained for the serum. The antibody titre was also much greater after first than after second infestation. This was attributed to the adult worm irritating the mucosa and stimulating the release of antibody; no adult worms were found after second infestation. The very low antibody titre of the serum relative to that of the mucous extract may be related to a. localized site of production within the mucosa of the gut. There was also a correlation between the site of infestation by the adult in the large lcolon and proximal colon, and the peak titre of the haemagglutinating antibody. This peak was also related to a peak in the relative concentration of ß and y-globulins in the mucus after first infestation and in the y -globulins after second infestation. The mucosal extracts were much richer in haemagglutinating antibody than either of the other two samples. Again the antibody titre was highest within the area infested by the adult worms, and there was a similar distribution of ß and y-globulins throughout this area as for the mucous exudate. The final extract tested was from the tunica muscularis. These exudates gave the lowest antibody titres of the three samples; this was related to the paucity of lymphoid tissue in the muscle layers.
Factors limiting the intake of feed by sheep. I. The significance of palatability, the capacity of the alimentary tract to handle digesta, and the supply of glucogenic substrate.
Authors: Weston RH
Published: November 2004

Voluntary feed consumption (VFC) decreased when a quantity of the diet being consumed by the sheep was introduced into the rumen. On diets of lucerne hay, lucerne hay plus maize, wheaten hay, and wheaten straw, the decreases in VFC ranged from 90 to 110% of the quantity introduced intraruminally when this quantity varied from 20 to 60% of the VFC during control periods. When sheep consumed wheaten straw ad libitum, and a quantity of coarsely ground wheaten straw equal to 140% of the VFC during a control period was given intraruminally, VFC ceased and digesta accumulated in the rumen. VFC decreased when indigestible materials were introduced into the rumen. The voluntary consumption of lucerne hay decreased by 15% when sawdust was introduced into the rumen at a rate equivalent by weight to 17% of the VFC during a control period ; decreases of 7 and 9% were found when finely ground polyvinyl chloride was introduced at rates equivalent by weight to 25 and 50% respectively of VFC during control periods. The voluntary consumption of wheaten hay decreased by 16 and 19% when sawdust was introduced into the rumen at rates equivalent by weight to 25 and 18% respectively of VFC during control periods. Intraruminal infusions of acetic acid, propionic acid, or a mixture of acetic, propionic, and butyric acids providing 290–510 kcal of energy daily were accompanied by decreases in the voluntary consumption of lucerne hay and wheaten hay; the decreases ranged from 0.29 to 0.86 g dry matter per kcal of energy infused; similar decreases were obtained when propionic acid was infused into the abomasum of sheep given lucerne hay. The intake of lucerne hay was 9% higher when given alone than when supplemented with 6% propionic acid. The results are discussed in relation to factors limiting the intake of lucerne hay and wheaten hay.
The source of protein in calf diets. I. A comparison of dried skim milk and meat meal
Authors: Leibholz J
Published: November 2004

Seventy-nine male Friesian calves were fed on diets containing meat meal dried skim milk as the protein supplement, between 35 and 77 days of age. Meat meal resulted in significantly greater (P < 0.05) liveweight gains but no change in the efficiency of feed conversion. Supplementation of the meat meal methionine did not improve the liveweight gains. The cost of raising a calf to 11 weeks of age has been calculated.
The source of protein in calf diets. II. Meat meal quality
Authors: Leibholz J , Moss FP
Published: November 2004

In experiments designed to study the effect of the quality of meat meal on growth and efficiency of feed utilization, diets containing meat meals from six different sources were given to 78 male Friesian calves between 5 and 11 weeks of age, 19 calves between 11 and 17 weeks of age, and 168 chickens. The source of meat meal resulted in a significant difference in liveweight gain in the calves; this was related to the calcium and cystine contents of the meat meals. For chickens the effect of meat meal source was dependent on the formulation of the diets. The free amino acid, ammonia, and urea concentrations in the blood plasma of both species are presented.
Competition among wheat plants sown at a wide range of densities
Authors: Puckridge DW , Donald CM
Published: November 2004

An experiment was undertaken with wheat (cv. Insignia 49) to study the effects of interplant competition on dry matter and grain production. Crops ranging in density from 1.4 to 1078 plants per sq. metre were established, and light intensity and growth measurements were made within the crop. Four sequential stages in the growth of the crop were recognized, namely: A period in which there was no interplant competition at any density. A period in which the crop growth rate showed a curvilinear relationship to the leaf area index and a linear relationship to light interception. A period when the weight of ears (early dough stage) showed a linear relationship to an expression involving the weight of green leaf in an earlier period and the percentage survival of tillers. A period of grain filling and ripening in which some further relative changes in ear and grain weight occurred. It is suggested that the application of this type of analysis to the reaction of different genotypes to crowding may add to an understanding of crop performance.
Growth of an annual pasture on virgin land in South-Western Australia including effects of stocking rate and nitrogen fertilizer
Authors: Greenwood EAN , Davies HL , Watson ER
Published: November 2004

A pasture of Bromus mollis L. and Trifolium subterraneum L., sown on virgin land, was grazed by sheep for 4 years. Three rates of ammonium sulphate were factorially combined with two stocking rates. Stocking rates of 8 and 12 sheep/ha had similar effects on growth rate of the sward and influenced botanical composition only in the second and third year of grazing. Ammonium sulphate increased the proportion of B. mollis and volunteer grasses, and reduced T. subterraneum and dicotyledonous volunteers. B. mollis persisted only where ammonium sulphate was applied. T. subterraneum, in the absence of nitrogen fertilizer, was highly dominant for 3 years, then declined to 40% by the fifth year. Where nitrogen fertilizer was applied in large quantities the clover did not persist even at the higher stocking rate. The annual dry matter production of the swards which did not receive the nitrogen fertilizer was poor (c. 6000 kg/ha); the possible causes of this are discussed. Ammonium sulphate increased winter growth in the early years of the experiment. In the later years, large quantities of straw accumulated on the ammonium sulphate plots, regeneration was poor, and the nitrogen fertilizer ineffective. Growth curves of the sown species are presented and discussed.
Pathological changes associated with Oesophagostomum columbianum infestations in sheep: Haematological observations on control worm-free and experimentally infested sheep.
Authors: Dobson C
Published: November 2004

Variations in the numbers of erythrocytes and white cells within the blood of sheep given various doses of Oesophagostomum columbianum larvae were studied over a period of 10 weeks. The sheep showed losses of red cells and haemoglobin, and the packed cell volume was diminished after infestation with O. columbianum. These effects increased in severity as the infesting dose was increased; the resistant state of the host also affected the blood picture. In all infestations the calculated absolute values for the blood, i.e. mean corpuscular haemoglobin (MCH), mean corpuscular volume (MCV), and mean corpuscular haemoglobin concentration (MCHC), did not significantly change except in the heavier infestations, where MCV increased for a time. The type of anaemia which predominated throughout these experiments was normocytic-normochromic. Where the MCV increased for a period, the anaemia was of the macrocytic-normochromic type. During the first infestation with 2000 larvae the anaemias tended to become microcytiohyperchromic, but these changes were not significant. Gross observations on the gut indicated that one of the factors influencing the development of anaemias was the extensive tissue damage caused by the larvae, which resulted in chronic bleeding from the mucosa. This suggestion was supported by the fact that anaemias also developed during second infestations when there was no adult worm population. The white cell counts from a number of these sheep were also recorded. The most significant changes occurred after second infestation, although a general increase was noted after all first infestations as well; prominent increases occurred in the agranulocytes and the eosinophil leucocytes. The neutrophil leucocyte counts fell throughout all the infestation. All the normal values obtained for the haemoglobin concentration, packed cell volume, red cell counts, MCV, MCH, and MCHC and white cell counts compared favourably with the values cited by other workers.
Relationship of coat type and colour to milk production in Australian Illawarra Shorthorn dairy cattle
Authors: Schleger AV
Published: November 2004

An investigation of the relationships of coat type and coat colour to milk production in the predominantly red Australian Illawarra Shorthorn breed of dairy cattle has been carried out in the Kingaroy district of Queensland. Coat type and shade of red colour were assessed in consecutive years at the beginning and end of lactation and were found highly repeatable. The correlation between each of the scores and milk yield was highly significant. The correlations at the beginning of lactation (r = –0.310**, d.f. = 235, and r = -0.287**, d.f. = 208) were not inferior to those determined at the end of lactation (r = –0.210**, d.f. = 235, and r = –0.336**, d.f. = 225 respectively). Hair diameter determined at the beginning of lactation was positively correlated with milk yield. While these characters are phenotypically correlated with productivity, the extent of their genetic component could not be tested in this investigation.
Physiological and ecological studies on the oestrogenic isoflavones in subterranean clover (T. subterraneum L.) V. Ontogenetic change
Authors: Rossiter RC , Beck AB
Published: November 2004

On plants of the same age, differences between leaves in the concentrations of the oestrogenic isoflavones daidzein (D), formononetin (F), genistein (G), and biochanin A (BA) were largely due to differences in leaf age. Concentrations of F, G, and BA declined during unfolding and development of the individual leaf. The maximum amounts per leaf of F, G, and BA were attained at the completion of the cell expansion stage. The appearance of D was associated with leaf senescence. The concentrations of F, G, and BA in expanded leaves usually declined during plant growth. An exception was F in the Yarloop strain. Relatively low levels of isoflavones were found in the stem + petiole fraction and in the roots, and intermediate levels in flowers. The relevance of these results to animal bioassays for oestrogenic activity is discussed.
The digestion of chopped and ground roughages by sheep. I. Movement of digesta through the stomach
Authors: Weston RH , Hogan JP
Published: November 2004

Digestion studies were conducted with lucerne hay and wheaten hay prepared for feeding either by chopping or by grinding and pelleting. The sheep were offered food every 3 hr. The rates of flow of water and the rumen volumes were measured by reference to a water-soluble marker. The replacement of a diet of chopped roughage by an equal amount of ground roughage caused a decline in the rate of flow of water from the rumen. With wheaten hay this decreased flow was accompanied by a decline in rumen volume, the retention time of the marker in the rumen remaining constant; with lucerne hay the rumen volume remained constant and the retention time of the marker increased. When the quantity of ground roughage feed was increased, rates of flow from the rumen and abomasum were enhanced and marker retention time in the rumen decreased. Under conditions of ad libitum feeding, the sheep consumed 75% more chopped lucerne hay than chopped wheaten hay; grinding was accompanied by an increase of 50% in the consumption of each hay. When levels of feeding were approximately 90% of the ad libitum intake, it was found that: (i) the rate of flow from the rumen appeared to be independent of diet and method of preparation of the feed; (ii) the rate of flow from the abomasum was higher with the ground roughage; (iii) rumen volume with ground lucerne hay was higher than with chopped lucerne hay or ground wheaten hay; it was also higher with chopped wheaten hay as compared with ground wheaten hay. Sheep spent less time ruminating and eating when the roughages were ground. The amount of metabolizable energy available for production from 1000 g of ground lucerne hay was 950 kcal; it was calculated that this would have declined by 9% if the sheep ruminated for the same time on this ground hay as on the chopped hay.
Effect of temperature and host on Paratylenchus neoamblycephalus and effect of the nematode on the host
Authors: Fisher JM
Published: November 2004

The optimum temperature for increase in number of Paratylenchus neoamblycephalus on apple seedlings was approximately 20°C, and at 30° numbers did not increase. Higher numbers of nematodes developed on apricot than on apple seedlings, but the growth of apple was reduced more than that of apricot. No histological or pathological symptoms caused by the nematodes could be detected. Changes in total numbers of nematodes appeared to be related to changes in numbers of females
The digestion of two diets of differing protein content but with similar capacities to sustain wool growth
Authors: Hogan JP , Weston RH
Published: November 2004

Measurements were made of the digestion in sheep of two diets of differing protein content but known to support similar levels of wool growth. When offered to the sheep at 500 g/day, the high protein (HP) diet provided 13.8 g nitrogen (N), while the low protein (LP) diet provided 5.5 g. With the HP diet, approximately 8.8 g N in forms other than ammonia passed daily through the pylorus; 6.8 g of this N was apparently digested in the intestines. The corresponding values for the LP diet were 8.1 and 6.2. The similarity in wool growth recorded with these diets, despite large differences in dietary protein intake, is consistent with the hypothesis that wool growth is limited by the quantity of amino acid N absorbed from the alimentary tract. The stomach was the site of 72–73 % of the organic matter digestion and more than 90% of the cellulose digestion that occurred in the whole alimentary tract. In addition, approximately 90% of the dietary soluble carbohydrate was apparently digested in the stomach. It was calculated, by making several assumptions, that the quantity of microbial crude protein synthesized in the rumen did not exceed 44–49 g/day, equivalent to 15–16 g/100 g organic matter digested in the rumen. The implications of this calculation in the protein nutrition of ruminants are discussed. The retention time of a soluble marker in the rumen was 15–18 hr, and rates of flow of digesta from the rumen and abomasum were comparatively low.
Water content and water turnover in beef cattle
Authors: Springell PH
Published: November 2004

Twenty-four steers, comprising British (Hereford and Hereford x Shorthorn), Zebu (Africander), and Zebu cross (British x Brahman or Africander) breeds, were either maintained on pasture, or yarded and fed on diets of a low and a high nutritional value. Tritiated water was injected into the animals on five occasions at intervals of 3 months. The body water content and the water turnover rate were calculated, and some of the sources of variation defined. Observed differences in the water content are attributable to nutritional factors rather than to breed differences. The mean body water content ranged from 615 to 809 ml/kg fasting body weight, where the higher values were associated with a poor diet. The mean half-life of tritiated water was lower in summer (as low as 58 hr) than in winter (up to 128 hr) in grazing and well-fed yarded steers. On a poor diet, however, the half-life in yarded cattle remained high and almost constant throughout the year, dropping to below 100 hr on only a single occasion. Occasionally the half-life was breed dependent, but generally no significant differences between breeds could be found. While mean turnover rates of up to 7.1 ml kg-1 hr-1 were found in better-fed cattle in summer, the value in poorly fed animals was almost constant throughout the year at about 3.3 ml kg-1 hr-1. There was, however, a winter minimum in the well-fed yarded and grazing groups. The turnover rate was also influenced by breed only to a limited extent. The results are interpreted in the light of their possible significance in the adaptation to a tropical environment, and in relation to their value in predicting the body composition.
The effects of soil moisture stress on the growth of barley. IV. The response to presowing treatment
Authors: Husain I , May LH , Aspinall D
Published: November 2004

The claim that a presowing treatment, consisting of two cycles of wetting and drying, reduces the susceptibility of barley to the effects of water stress during growth (Genkel 1946) was investigated. Barley grain of two varieties was treated by the techniques recommended by Genkel and was then subjected to water stress treatments of short or long duration. Apart from a 15% increase in grain size on plants subjected to water stress late in development, no persistent effects of the treatment were found, and no evidence to support Genkel's claims of increased yield under water stress conditions. Possible reasons for the evident difference between these data and those of Genkel are discussed.
The effect of temperature at early flowering on the growth and development of peanuts (Arachis hypogaea)
Authors: Wood IMW
Published: November 2004

The effect of a number of temperature treatments on peanuts, applied during a 12-day period soon after the onset of flowering, was studied in a phytotron on a Spanish type variety, Spantex. The treatments were 30/20, 30/25, 30/30, 30/35, 20/25, 25/25, and 35/25°C (day temperature/night temperature). Prior to and following the application of the temperature treatments the plants were grown under a regime of 30125°C. Relative growth rates and net assimilation rates (leaf dry weight basis) were both affected during the temperature treatment, with a maximum rate for both at 25/25°C. Flowering was also markedly affected, low temperature favouring flower formation. There was no evidence of a thermoperiodic effect on flower production. Temperature and the period of exposure to that temperature appeared to be the chief determinants of flower production. Following the temperature treatments, when all plants were being grown under the same regime, there were marked residual effects on both flowering pattern and vegetative growth. The residual effects on flowering could not be related to the number or weight of developing fruits, and it was concluded that the developing fruits did not suppress flowering. The temperature treatments also led to large differences in the final nut-in-shell and kernel yields. These differences were largely associated with the number of developing pegs, which in turn were correlated with the flower production up to the end of the temperature treatments. It is suggested that the effects of temperature on final yield were the result of temperature on growth leading to differences in flower formation.
The growth of the young coconut palm (Cocos nucifera L.). I. The role of the seed and of photosynthesis in seedling growth up to 17 months of age
Authors: Foale MA
Published: November 2004

The growth of coconut seedlings and the changes occurring within the seed were studied over a period of 17 months from the germination of the coconuts. Removal of the husk prior to germination made possible an estimate of the endosperm content of each seed and also permitted the exact date of germination to be observed. Seedlings were grown with a non-limiting supply of water and nutrients; 63 seedlings were harvested on each of 10 occasions to enable a growth analysis to be made. A high initial relative growth rate, arising through contributions by the endosperm, fell at 4 months to a level which remained roughly constant to 17 months. By 4 months the haustorium had reached its full size, but thereafter the relative contribution from the endosperm via the haustorium was much diminished. Between 4 and 15 months a gradual change over to full dependence on photosynthesis took place. By 17 months less than 10% of the endosperm remained in the nut. The rate of leaf production was constant with time, but the leaf area increased almost exponentially. There was some indication of a positive relationship between net assimilation rate and solar radiation. Some conclusions are drawn concerning cultural methods with young coconuts.
Growth rates of Rhizobium trifolii and Rhizobium lupini in sterilized soils
Authors: Chowdhury M/S , Marshall KC , Parker CA
Published: November 2004

The growth characteristics of Rhizobium trifolii and R. lupini in a sterilized infertile sandy soil were studied at different temperatures. R. trifolii grew at a faster rate than R. lupini at all temperatures up to 30°C. The optimum temperature for growth for both species was found to be approximately 30°. Temperatures higher than 35° were found to be lethal for both species, the cells of R. trifolii being the more sensitive. In a fertile sandy loam the growth rates of both species were improved, the effect being more pronounced with R. lupini. The presence of the appropriate host plants in the sterilized infertile sand resulted in faster growth rates in both species, particularly R. lupini.
Growth and senescence of the grape berry*
Authors: Hale CR
Published: November 2004

Benzothiazole-2-oxyacetic acid (BTOA) was applied to bunches of grapes (Vitis vinifera cv. Shiraz) at different times during their development and its effect on their subsequent growth was followed by measuring changes in berry weight, reducing sugars, malate, and tartrate. It lengthened the slow growth phase of berry development and this delayed ripening. It had no effect on the course of the first or second rapid growth stages. Greatest response to a single application was obtained when BTOA was applied at the end of the first growth stage or during the first week of the lag phase. Two and three applications made at 2-weekly intervals lengthened the lag phase more than a single application. During the prolonged lag phase malate continued to increase and reached a higher maximum than in untreated grapes. No consistent effect of BTOA on the tartrate content of grapes was apparent. The response of grapes to treatment with BTOA and other auxins is discussed in relation to growth and senescence of the grape berry.

* This work was initiated at the Australian Wine Research Institute, Glen Osmond, S.A. 5064, Australia.
Toxicity of Swainsona canescens for sheep in Western Australia
Authors: Gardiner MR , Linto AC , Applin TEH
Published: November 2004

The botanical description and distribution of a Western Australian species of Swainsona is reported in connection with investigations of the plant as a poison plant responsible for extensive losses of sheep and horses in the Goldfields station country. Feeding trials in sheep and rabbits confirmed the toxicity of Swainsona. Sheep exhibited depression, anxiety, "blind staggers", incordination, and emaciation. The central nervous system of both animal species was seriously affected, with chromatolytic and vacuolar degeneration of neurones and with oedematous changes. Renal cells showed hydropic degeneration and spleens were intensely haemosiderotic. These changes occurred after 4 or 5 weeks of chronic feeding and closely resembled those of locoweed poisoning of livestock in the western United States.