bluuebunny/crossref_metadata_2025 huggingface dataset:
Quantative inheritance in Lucerne, Medicago sativa L. I. Inheritance and selection for winter yield
Authors: Morley FHW , Daday H , Peak JW
Published: November 2004

Spaced plants of lucerne, Medicago sativa L., derived from 10 strains and 44 F1's, grown in the field at Canberra, exhibited discontinuous variation in winter growth. Some were completely dormant, others grew at over 40 per cent. of their summer rate. Strains differed with respect to combining ability for growth rates, both in summer and in winter, but differences between strains in combining ability were much more evident in minter than in summer. The correlation between winter and summer growth rates was markedly affected by differences in winter dormancy. Thus the Canadian Creeping-rooted strain, which had the highest combining ability for summer growth, was among the poorest for winter growth. Within strains or crosses, winter and summer growth rates were strongly correlated (r = 0.77), presumably because genotypes within such lines were relatively homogeneous with respect to winter dormancy. The Hairy Peruvian strain, and to a lesser extent Hunter River, Provence, and an Australian selection, showed high combining ability for winter growth. In other experiments winter dormancy was broken by either increased temperatures (heated glass-house) or by supplementing the natural day length with low-intensity artificial light. These treatment effects were supplementary without interaction. In one set of material a highly significant genotype (clone) X temperature interaction, and the absence of a genotype X day length interaction, indicated that genetic differences in dormancy could be determined largely by the response to low temperatures. For the present neither short days nor low temperatures alone seem sufficient to distinguish between winter-active and winter-dormant genotypes. The growth rates of some genotypes in winter provide encouragement for the introduction, selection, and management for increased winter production of lucerne and other species. The behaviour of the strains in the field, and published evidence on this and other species with a temperate-subtropical distribution, indicates that genes for winter activity are most likely to be found in the warmer parts of the distribution.
The growth of swards of subterranean clover with particular reference to leaf area
Authors: Davidson JL , Donald CM
Published: November 2004

An experiment was conducted to study the growth of subterranean clover (Trifolium subterraneum L.) sown at different densities; the control swards were not defoliated while others were subjected to a single defoliation at various dates. During the final month the rate of dry matter production (tops only) increased to a maximum when the leaf area index (the ratio of the area of the leaves to the area of the ground surface — L.A.I.) was about 4-5, falling by about 30 per cent. as the L.A.I. increased to 8.7. The rate of leaf production was greatest at about L.A.I. 4-5, falling to zero at L.A.I. 8.7. Climatic conditions during the growing season influenced the relationship of L.A.I. to growth; as conditions became more favorable the values of the optimum LA.1. for growth and of the ceiling L.,4.1. progressively rose. Irrespective of the density, all swards tended towards a common ceiling L.A.I. and yield by the end of the season. The effect of defoliation depended on the L.A.I. at which defoliation occurred, on the value to which the L.A.I. was reduced, and on current climatic conditions. If swards near the ceiling L.A.I. were defoliated, total dry matter production was slightly increased and there was a great increase in leaf production. On the other hand, defoliation of swards from about the optimum L.A.I. to very low L.A.I. values led to a substantial reduction in both dry matter and leaf production. It is suggested that all these effects depend on the light relationships within the sward and their influence on the balance of photosynthesis and respiration. Pasture at the optimum L.A.I. will give greater production than swards of lower or higher L.A.I.; defoliation can give greatly increased leaf production, unless L.A.I. is reduced to very low values.
A red strain of Rhizobium from Lotononis bainesii Baker
Authors: Norris DO
Published: November 2004

A strain of Rhizobium that is red in culture was isolated from Lotononis bainesii and appears to be a normal symbiont of this species. Cultural characteristics of the bacterium and the results of cross-inoculation tests are described.
Renal function of sheep in hot environments
Authors: McDonald J , Macfarlane WV
Published: November 2004

The renal functions of adult Merino and crossbred sheep have been measured throughout the year in Brisbane (lat. 27° S.), and during acute and chronic exposure to hot environments (temperature 43°C dry bulb, 36°C wet bulb). In summer, glomerular filtration reached twice the rate found in winter and it rose during 2-9 weeks' exposure to heat. There was no change of glomerular filtration during 4 hours' acute heating at 43-44°C dry bulb (36-37°C wet bulb). Renal plasma flow, estimated by p-aminohippurate clearance, showed no variation with season, nor with exposures to heat. The mean tubular maximum of secretion of p-aminohippurate (TmPAH) of individual sheep ranged from 70 to 110 mg/min (2.1-2.6 mg/kg/min). These values are nearly twice those reported for other species. Some sheep showed depression of the TmPAH on long exposure to heat.
Total counts of microorganisms in the fleece of two Corriedale fleece types
Authors: Mulcock AP , Fraser IEB
Published: November 2004

The number of bacteria in the fleece of Corriedale sheep has been shown to vary with rainfall. A significant difference has also been found between the numbers of bacteria in the fleece of sheep which have been selected as immune and susceptible, respectively, to bacterial discoloration. After heavy rain no difference could be found in the numbers of bacteria in the two fleece types, but susceptible fleeces tended to have a greater and less variable number of bacteria than immune fleeces over the subsequent drier periods.
The effects of inbreeding on four families of Peppin Merinos. III. The influence of crude pituitary extract on inbred lambs
Authors: Doney JM
Published: November 2004

Treatment of inbred lambs with crude pituitary extract produced a highly significant increase in griwth rate over the first 10 weeks when compared with untreated inbred lambs. Continued treatment from 10 to 23 weeks of age did not cause any further change in growth rate. Differences between treated and untreated lambs in body weight and size were maintained long after cessation of treatment. Wool production was significantly increased during, but not after, the treatment period. At 12 months of age (7 months' fleece), treated and untreated groups did not differ significantly in wool production, mean fibre weight, mean fibre length, or total fibre number. The ratio of secondary to primary follicles did not differ significantly at any stage. Similar treatment produced no detectable response in non-inbred lambs. It is suggested that the effect of inbreeding is partially derived from a reduction in pituitary activity. Treatment of inbred lambs caused a decrease in the variances of body weight and size and an increase in the variance of wool production. This may be explained by differences between different tissues in their hormone requirements for maximum response, and would suggest that the effects of inbreeding on the variance of any character depend on the physiological paths through which the effect is produced.
Limitations to animal production imposed by seasonal fluctuations in pasture and by management procedures
Authors: Willoughby WM
Published: November 2004

An experiment with Merino wethers on a Phalaris tuberosa-subterraneum clover-volunteer grass pasture has compared throughout an annual cycle the effects of:

(a) Seasonal fluctuations in quantity and quality of pasture on liveweight gains and wool production in sheep.

(b) Different grazing systems at equal stocking rates both on pasture growth and on liveweight and wool production in sheep. (a) Availability of dry pasture did not affect animal production so long as green pasture was present. Small increases in green pasture in the period of slow growth (winter) gave large increases in liveweight and wool production. Large increases in green pasture in the period of rapid growth (spring) had no effect on the animal. On dry pasture (summer) heavy sheep lost more weight than light sheep. Increasing the amount of dry pasture reduced liveweight loss only slightly but resulted in a greater rate of breakdown of plant material. An asymptotic relationship between availability of green pasture aid animal gain is presented, the asymptote in this instance occurring at a,pproxirnatnly 1400 lb dry matter per acre. The implications of the results are discussed with reference to methods of investigation of species, fertilizers, end management procedures aimed at 01-ercoming pasture limitations to animal production. The validity of investigations which do not take into account the relative constancy of grazing pressure throughout the year, and the continuing effects of plant on animal and animal on plant, is questioned. (b) Regardless of the degree to which pastures had been checked by grazing in spring, all dried out simultaneously on the onset of summer, and all sheep on all treatments reached their peak liveweight turning point on approximately the same date. Less than one-third of the liveweight gain potential of the pasture was attained on any one of the three grazing systems. The mean amounts of the individual pasture components, and of the total weight of pasture, were identical at any one time under the three grazing systems. The closer the systems approached towards continuous grazing the greater were the liveweight gains and wool production.
The influence of maturity grading on total yield and seed production in strains of Trifolium subterraneun L. grown as single plants and in swards
Authors: Rossiter RC
Published: November 2004

A large number of strains of subterranean clover was grown as single plants and in swards in a series of 1-year experiments. The relationship between the interval from seeding to flowering ("maturity grading") and the production pattern varied according to plant density. In the case of single plants, both total yields and seed yields increased linearly with increasing maturity grading. With swards, on the other hand, total yields showed scarcely any relation to increasing maturity grading – there was a slight decline, in fact – while seed production fell rapidly. Hence the early strain Dwalganup gave the lowest seed yields as single plants, but the highest seed yields in swards, whereas the reverse situation held for the late strains Wenigup and Tallarook. The main factor responsible for the differences in these production patterns was considered to be available soil moisture supply. It was shown that in the few cases where soil moisture was severely limiting in spring for single plants, yields levelled off (and seed yields even declined) at higher maturity gradings. Three points are discussed at some length: the influence of environment on the seed yield of strains grown as single plants, the effect of plant density on the ratio seed weight/total weight, and production in relation to maturity grading in swards.
Seasonal variations in wool growth and heat tolerance of sheep. II. Heat tolerance
Authors: Wodzicka M
Published: November 2004

The heat tolerance of rams at an air temperature of 105°F (40.6°C) and 34 mm Hg water vapour pressure was studied over a period of 1 year at Beltsville, Maryland. The rams were more heat tolerant in summer than in winter. This difference was significant (P < 0.001). Tolerance was less in July than in June and August. The reasons for this are discussed. Shearing increased the heat tolerance of rams (P < 0.001), presumably by enhancing the efficiency of evaporative cooling from the skin. There is evidence that shearing reduced heat acclimatization, especially during the cooler months.
Wool follicle population of some Indian breeds of sheep
Authors: Krishnarao MV , Schinckel PG , Clarke WH
Published: November 2004

One hundred and thirty-seven samples of skin from six Indian breeds of sheep (Nilgiri, Bikaneri, Bellary, Black Kurumbai Adu, Mandya, and Nellore) were obtained from Madras and Andhra States in south India. The samples were collected, processed, and examined by the methods described by Carter and Clarke (1957a, 1957b). Representative values for (i) mean number of follicles per sq. millimetre of skin, (ii) ratio of secondary follicles to primary follicles, (iii) mean fibre diameter, and (iv) ratio of diameter of fibres in primary follicles to diameter of fibres in secondary follicles were: Nilgiri, (i) 16.0, (ii) 3.5, (iii) 26.0 µ, (iv) 1.2 ; Bikaneri, (i) 14.0, (ii) 2.0 , (iii) 35.0 µ, (iv) 1.7; Mandya, (i) 10.5, (ii) 1.8, (iii) 55.0 µ, (iv) 3.8 ; Bellary, (i) 6.6, (ii) 1.4, (iii) 56.0 µ, (iv) 3.1 ; Nellore, (i) 6.0 , (ii) 1.7, (iii) 60.0 µ, (iv) 5.3; Black Kurumbai Adu, (i) 7.8, (ii) 1.2, (iii) 48.0 µ, (iv) 2.0. On the basis of these examinations the Nilgiri is classified as a down-wool breed, the Bikaneri as a good carpet-wool breed, the Bellary, Mandya, and Black Kurumbai Adu as coarse carpet-wool breeds, and the Nellore as a hair sheep.
Drought feeding of cattle. II. Comparison of daily and weekly feeding of all-grain rations: with observations on vitamin A status
Authors: Southcott WH , McClymont GL
Published: November 2004

Hereford steers and heifers in poor store condition, and from 16 to 22 months old, were fed daily or weekly on whole wheat at the rate of 3.5 lb (estimated to supply 2.5 lb of starch equivalent) per day with the addition of 1 per cent. finely ground limestone. In one experiment of 16 weeks' duration, weights were maintained at about the same level (450 lb) in both groups. However, when the experiment terminated the cattle from the weekly fed group were livelier, had shed their winter coats to a greater extent, and showed more advanced eruption of the incisor teeth. In addition the values for haematocrit, haemoglobin, and red cell counts were significantly higher. In a second experiment over a period of 19 weeks, the average weights fell from 469 lb to 438 lb in the daily fed group and to 403 lb in the weekly fed group. The difference in liveweight was not significant. No improvement was observed in the activity or appearance of the cattle on weekly feeding on this occasion, although haematological examinations showed a trend in favour of this group. Additional experiments confirmed the practicability of weekly feeding for cattle and the relative ease with which the system could be introduced. However, weekly feeding incurred a greater risk of digestive disturbance and losses were heavier than with daily feeding. Cattle on carotene-deficient drought rations for 38 weeks showed no patent night blindness or other evidence of vitamin A deficiency, although individual serum vitamin A values fell as low as 2 µg per 100 ml.
The growth of cocksfoot (Dactylis glomerata L.) under spaced plant and sward conditions
Authors: Knight R
Published: November 2004

The cumulative growth of nine clones of Dactylis glomerata was compared under two conditions of spacing. The first spacing was chosen to provide conditions similar to those of a breeding nursery, the second, conditions met with in swards. Data were obtained for two growing seasons, the individual plant and its parts being considered at each harvest. Of the nine clones seven were developed from plants obtained from the Mediterranean region and two from Great Britain. There was a poor correlation between plants under the two spacing conditions, particularly as later in the life of the swards clones reacted differently to competition. Competition did not lead to a uniformity of top weight for the clones in the swards. These results are discussed in relation to the conflicting results of similar studies and the reaction of genotypes to factors of the environment affecting growth. It is suggested that plants in the vegetative phase are affected by competition differently from plants in the reproductive phase. Some clones were found to regenerate after summer dormancy more rapidly than others, but initial advantages were not maintained. The relative development of parts of the plants differed between clones, some having high proportions of their total weight below ground. At the time of reproduction, despite very large differences in total weight between plants of a clone under the two spacing conditions, the percentages of plant parts were very similar. A high mortality was shown during the summer by the two clones from northern European plants, but only a negligible mortality by the Mediterranean plants.
Recovery of available soil nitrogen by annual fodder crops at Katherine, Northern Territory
Authors: Wetselaar R , Norman MJT
Published: November 2004

In 1958-59, a field trial was carried out at Katherine, N.T., to compare the recovery. of available soil nitrogen by fodder sorghum, Sudan grass, and bulrush millet when grown after an all-grass ley, a legume ley, and a long period of fallow. After 6 years of grass, available soil nitrogen remained low throughout the cropping season at all soil levels to a depth of 5 ft, and nitrogen yield from the fodder crops averaged only 17 lb/acre. After 7 years of Townsville lucerne, available soil nitrogen was low at the start of the season, but soil nitrogen was quickly mineralized and, in the absence of a crop, was leached to give a peak concentration of nitrate nitrogen at 2–3 ft. All three crops intercepted this mineral nitrogen efficiently to give an average aboveground nitrogen yield of 75 lb/acre, approximately half the nitrate nitrogen available in the 5 ft soil layer on uncropped land at the end of the season. After 5 years of clean fallow, soil nitrogen had been mineralized and leached to a considerable depth, 260 lb of nitrate nitrogen per acre being accumulated in the 0–5 ft layer. Fodder sorghum and Sudan grass depleted soil nitrogen appreciably in the 0–2 ft layer, and gave an average above-ground nitrogen yield of 62 lb/acre. Bulrush millet depleted soil nitrogen throughout the 0–5 ft profile to give a nitrogen yield of 154 lb/acre. Bulrush millet is therefore regarded at Katherine as an outstanding crop for the recovery of deep accumulations of soil nitrate nitrogen and their conversion to harvestable fodder protein.
Varietal reaction and genetic resistance of subterranean clover (Trifolium subterraneum L.) to subterranean clover stunt virus infection
Authors: Grylls NW , Peak JW
Published: November 2004

Resistance to subterranean clover stunt virus was explored in 390 strains and named varieties of subterranean clover from the Mediterranean regions, England, France, the Iberian peninsula, New Zealand, and Australia. High levels of genetic resistance were shown in the Australian varieties Tallarook, Hill's Small, and Bass B. Resistance of a selected group of F2's was found to be midway between that of the parents. In selected groups of F4 generation hybrids, and in selected second and third generation backcrosses, resistance equal to that of Tallarook was shown. The apparent recovery of some plants during tests in the glass-house was shown to be a form of temporary tolerance to the virus.
Aphid transmission of broad bean wilt virus and comparative transmission efficiency of three vector species
Authors: Stubbs LL
Published: November 2004

Broad bean wilt virus has been transmitted experimentally by the green peach aphid, Myzus persicae (Sulz.), by using short feed techniques as applied to non-persistent viruses. A comparative study of transmission was made between this aphid and the aphids Aphis craccivora Koch and Macrosiphum euphorbiae (Thos.). After short (10–15 sec), naturally terminated access probes on low concentration virus source plants, and successive single probe transfers, starved pairs of M. persicae aphids infected 27 of 110 plants inoculated in two experiments, whereas A. craccivora failed to infect any test plants. In comparisons between individual starved aphids given single access and transmission probes on high concentration virus source plants, the infection rate for M. persicae approximately trebled those of A. craccivora and M. euphorbiae. Differences in transmission ability were generally more pronounced when aphids probed low concentration virus source plants. Groups of 10 M. persicae were able to transmit after a 24 hr access to a high concentration virus source plant, but less efficiently than after single access probes on the same plant. The virus was not retained by the aphid after an additional 24 hr period on healthy broad beans. A. craccivora failed to transmit after a 24 hr exposure to the same source. The experimental results provide an explanation of the manner of field spread of the virus, and of the control obtained by regulation of sowing time. They also demonstrate that broad bean wilt is a typical non-persistent virus, apparently unrelated to other viruses which infect broad bean.
Soil fertility changes in the long-term experimental plots at Kybybolite, South Australia. II. Changes in phosphorus.
Authors: Russell JS
Published: November 2004

The fate of phosphorus applied as superphosphate and rock phosphate to grassland plots at Kybybolite established in 1919 on solonetzic soils has been studied by soil analytical techniques. The additional effect of the amendments lime and gypsum has also been examined. From past records of phosphorus added as fertilizer, the probable amounts of phosphorus removed in animal products, and present phosphorus levels of the surface 8 in. of soil, it has been possible to draw up a balance sheet of gains and losses. The results show that considerable penetration of phosphorus applied in the water-soluble form has occurred. Less than half the phosphorus applied as superphosphate can be accounted for in the surface 8 in. The remainder is presumed to have been leached to lower soil horizons. In contrasting these results with those of other areas of similar rainfall where little movement of applied water-soluble phosphate has occurred, it is believed that the greater penetration at Kybybolite can be explained on the basis of the coarse texture and the low fixing capacity of the surface soil. Where acid-soluble phosphate has been applied, less movement through the soil is apparent, and 75–89 per cent. of the residual phosphorus applied as rock phosphate can be accounted for in the surface soil, mostly in the top 2 in. Lime has resulted in an increased retention of phosphorus in the surface soil. Gypsum, on the other hand, has not resulted in increased retention. The need for a reappraisal of the present widespread practice of continuous mono-application of superphosphate to pastures after residual levels in the soil have been raised is discussed. In particular, the possible role of acid-soluble phosphate is examined.
A comparison of the mineralization of nitrogen and of sulphur from decomposing organic materials
Authors: Barrow NJ
Published: November 2004

The decomposition of a wide range of plant materials added to soil waa studied by measuring the production of carbon dioxide, and changes in the concentrations of ammonium and nitrate nitrogen and sulphate sulphur. The amount of sulphur mineralized depended on the sulphur content and the carbon/sulphur (C/S) ratio of the organic matter in much the same way as the amount of inorganic nitrogen depended on the nitrogen content and the carbon/nitrogen (C/N) ratio. For any given C/S or C/N ratio the sulphur or nitrogen mineralized varied within quite wide limits. With a 12 week decomposition period, initial C/S ratios of 200 and 420 were the minimum and maximum values at which no mineralization of sulphur occurred. The corresponding values for nitrogen were 16 and 44. Calculations indicated that the microbial residues from easily decomposed materials had a C/N ratio of 6–7 and a C/S ratio of 50–60, but with the residual organic matter from the more resistant materials the ratios were wider. Where large quantities of nitrogen were mineralized the decomposition of the native organic matter was stimulated.
The influence of rootstocks on the composition of oranges, with special reference to bitter principles
Authors: Kefford JF , Chandler BV
Published: November 2004

A study was made of the effects of rootstock on the composition of Washington Navel oranges grown on eight rootstocks and Valencia Late oranges grown on three rootstocks in several regions during six seasons. Among the three major commercial rootstocks, trifoliate orange and rough lemon exerted contrasting influences on orange composition, while sweet orange occupied an intermediate position. The effects of rootstock were similar on both scion varieties but were more marked with Washington Navel oranges. Trifoliate orange stock tended to give high yields of juice which was high in acidity and soluble solids content but low in ascorbic acid content and in bitter taste when canned. Rough lemon stock tended to give low yields of juice which was lam- in acidity and soluble solids content but high in ascorbic acid content and in bitter taste. A positive correlation was demonstrated between the bitter taste of canned juices and the concentrations of limonoid bitter principles in the peel of Washington Navel oranges, and in the peel and seeds of Valencia Late oranges. Trifoliate orange stock promoted the disappearance of bitter principles from all parts of the fruit with advancing maturity, but rough lemon stock retarded this process. Tangelo and Cleopatra mandarin stocks resembled trifoliate orange in their effects on orange composition. while sweet lime, Kusaie lime, and East Indian lime stocks resembled rough lemon.
Photoperiodism and sexual activity in Merino ewes. I. The effect of continuous light on the development of sexual activity
Authors: Radford HM
Published: November 2004

Sixteen Merino ewes were subjected to continuous light made up of daylight during the day and artificial light at night for a period of 3 years from the time the ewes were 2–3 months old. Sexual activity in these exes was compared with that in 16 control ewes held in natural daylight. Criteria of sexual activity mere the occurrence of oestrus and ovulation. Oestrus was inferred from the presence of colour marks on the rumps of the ewes which were run with vasectomized rams painted on the brisket with sheep-branding fluid. Ovulation was inferred from the occurrence of characteristic changes in the vaginal contents. Compared with the activity exhibited by the control ewes, the occurrence of oestrus, but not of ovulation, was apparently partly suppressed by continuous light during the first year and was more variable during the second year of the experiment. There was little difference between the two groups in the third year. Despite the initial suppression of oestrus, most ewes under continuous light exhibited sexual activity which was seasonal in nature and little different from that exhibited by the control ewes. Subsequently the continuously lighted eves from the first experiment were subjected variously to continuous light of constant intensity alone or to continuous light of constant intensity on which daylight was superimposed, with and without exposure to rain and wind. Compared with the activity exhibited by control ewes, continuous light of constant intensity alone permitted, if anything, an increase in sexual activity. The results do not fit any existing hypothesis for photoperiodic control of sexual activity in Merino ewes, and several alternative suggestions are discussed.
Border and orientation effects and their elimination in experimental swards of subterranean clover (Trifolium subterraneum L.)
Authors: Black JN
Published: November 2004

Two experiments were carried out in swards of subterranean clover, of the variety Bacchus Marsh, to determine the width of the border required firstly at the edge of swards and secondly between harvest areas. Peripheral growth was restricted by (a) root panels, (b) leaf panels, and (c) root and leaf panels; a fourth treatment with no lateral restrictions was also used. The results showed that in a sward growing without restrictions, a border at the edge of only 2 in. was required before homogeneous dry weights were reached. This border effect could be eliminated by using leaf- or leaf- and root-restricting panels, but not by root panels alone. The data for borders between harvest areas were more difficult to interpret, but growing swards without panels while allowing for a 3 in. border, both at the periphery and between defoliated areas, is recommended as the simplest procedure. From a consideration of marginal growth under the different peripheral restriction regimes it was concluded that water and nutrients were non-limiting, but that sward growth was limited by the amount of light energy intercepted.
The development of rumen function in the lamb.
Authors: Wardrop ID , Coombe JB
Published: November 2004

A series of experiments is presented, describing the development of the rumen function in grazing lambs and the effects of' diet on the rumen development of artificially reared lambs. In grazing lambs the volume of the abomasum contents showed little change with age. The volume of the rumen contents increased with age, and the rate of' this increase was most marked from 3 weeks of age onwards. The volume of the rumen contents, relative to both the liveweight and the volume of the abomasum contents, was constant from 8 weeks of age onwards. The rumen volatile fatty acids (V.F.A.) concentrations in grazing lambs increased from birth and reached adult levels at 8 weeks of age. The total quantity of V.F.A. present in the rumen at a given time, relative to liveweight, increased up to 8 weeks of age but from this age onwards was approximately constant. The rumen ammonia nitrogen (N) concentrations in grazing lambs were high for the first few weeks after birth, but showed a continuous fall, reaching adult levels at 5 weeks of age. The quantity of ammonia N present in the rumen at a given time, relative to liveweight, increased up to 8 weeks of age and then remained approximately constant. The rumen volumes, V.F.A., and ammonia N concentrations were normal only in lambs that had been fed roughage. When lucerne chaff was fed to young lambs, the digestibilities of the dry matter, crude protein, and crude fibre were high, irrespective of whether the previous diet had been milk or chaff. The ad libitum dry matter intake from roughage, relative to the liveweight, increased up to 8 weeks of age and then remained approximately constant. When roughage was fed to lambs which had been reared on 'milk' (a preparation from dried cows' milk) only from birth to 9 weeks of age, the rumen V.F.A. concentrations rose immediately and levelled off at adult levels within 1 week.
Herbage as a source of digestible organic matter and digestible nitrogen for the grazing sheep.
Authors: Vercoe JE , Tribe DE , Pearce GR
Published: November 2004

An experiment is reported in which the digestible organic matter and digestible nitrogen intakes of Corriedale wethers grazing on improved pastures in a Mediterranean- type environment 1%-ere measured by the faecal index method from August 1957 to August 1958. The mean digestible nitrogen intake fell from a maximum of 50 g/clay in the spring to a minimum of 6 g/day in the late summer, and reached an autumn maximum of 13 g/day before falling to a winter minimum of 8 g/day. The mean digestible organic matter intake fell from a maximum of 1500 g/day in the spring to a summer minimum of 600 g/day, rose again to an autumn maximum of 1000 g/day, and fell again to a winter minimum of 600 g/day. The results are discussed in relation to the theoretical maintenance requirements of the sheep and the nutritional value of herbage.
The use of irradiated larvae as immunizing agents in Haemonchus contortus and Trichostrongylus colubriformis infections in sheep
Authors: Mulligan W , Gordon HMcL , Stewart DF , Wagland BM
Published: November 2004

Six of 10 lambs previously given two doses of irradiated (60 kr) Haemonchus contortus larvae showed solid resistance to an experimental challenge with 10,000 larvae. The remaining four lambs in the group developed moderate infections. Nine of 10 lambs previously given two doses of irradiated (80 kr) Trichostrongylus colubriformis larvae showed solid resistance to an experimental challenge with 30,000 larvae. The 10th lamb was moderately resistant. Doses of X-rays within the range 40–100 kr had no effect on the exsheathment of H. contortus in the rumen, but few male worms developed as far as the fourth stage. It seems likely that the irradiated males and possibly a significant proportion of the irradiated females are unable to complete the ecdysis from the third to the fourth stage.
Identification of Merino rams homozygous for the poll gene
Authors: Dun RB , Morrant AJ
Published: November 2004

A total of 23 ram lambs were produced from matings between homozygous polled Merino rams (PP) and heterozygous polled Merino ewes (Pp). The genotype of the ram lambs was established by progeny testing, and a comparison between genotype and phenotype was made. At birth, seven out of nine PP ram lambs showed clean depressions at the horn sites, whereas all of 14 Pp rams showed knobs set in depressions. At 15 months of age, the range of phenotypes with regard to horn growth was: PP rams: Least expression – a smaIl knob set in a depression; no horn growth.
Greatest expression – a scur ½ in. long (horn volume. 0.012 cu. in.) attached to a large knob set in a depression. Pp rams:

Least expression – a scur ¾ in. long (horn volume, 0.180 cu. in.) set in a depression.

Greatest expression – a scur 8 in. long (horn volume, 12.400 cu. in.) with absence of depressions. From examination of horn growth in a group of 36 Pp rams, it was concluded that in diagnosing the genotype of 15-month-old poll Merino rams, approximately 3% (0-15%; P < 0.05) of hetorozygotes would be misclassified as homozygotes if the dividing line between genotypes was taken at 0.05 cu. in. of horn growth. In a second group of 196 Pp rams, observations on scur length indicated that a little over 1% of overlap types were present. On discussing this information relative to the establishment of homozygous polled Merino flocks, the following conclusions were drawn:(1) A large percentage of Pp rams could be diagnosed at lamb marking by the presence of horn growth on large knobs set in depressions (scores DK + or DS). (2) The measurement of horn volume at 15 months of age will differentiate Pp and PP types with accuracy equivalent to a progeny-testing scheme involving five lambs per sire.
Temperature regulation in the new-born lamb. IV. The effect of wind and evaporation of water from the coat on metabolic rate and body temperature
Authors: Alexander G
Published: November 2004

The study of temperature regulation in new-born lambs has been extended from dry lambs in "still air" at various ambient temperatures to dry lambs in a wind of 550 cm sec-l, and to lambs whose coats are drying. Exposure to wind resulted in an increased slope of the line relating heat production to ambient temperature, but under the experimental conditions evaporation of water from the coat added approximately the same increment at all ambient temperatures. The effects of wind and evaporation at any one temperature appeared additive. The heat loss from naturally wet new-born lambs less than 1 hr old, in a wind, was greater than in slightly older lambs wetted with tap water. Lambs with hairy coats were able to conserve heat more readily than lambs with fine coats. The cooling efficiency of evaporation from the coat was about 25%. The elevation in temperature of the extremities which follows feeding and persists under conditions of moderate heat loss, appears to be almost abolished under conditions of high heat loss. During the studies on drying lambs, beat loss in many lambs exceeded heat production, and rectal temperature fell, which thus indicated the maximum possible heat production (summit metabolic rate) of which lambs are capable. Lambs from ewes on low or medium levels of feeding during pregnancy cooled more readily than lambs from well-fed ewes.
Culture and consignment techiques used for parasites introduced against Queensland fruit fly. (Strumeta tryoni (Frogg.))
Authors: Snowball GJ , Wilson F , Lukins RG
Published: November 2004

The paper describes techniques used in rearing and transporting parasites of the oriental fruit fly (Dacus dorsalis) liberated in Australia against the Queensland fruit fly (Strumeta tryoni) during 1956–1959. The principal species reared were Opius oophilus, O. vandenboschi, and O. longicaudatus at Sydney and Honolulu, and O. incisi at Honolulu only. The laboratory hosts were Strumeta tryoni alt Sydney and Dacus dorsalis at Honolulu. A culture medium consisting of banana tissue and a carrot-yeast mixture was developed in which the immature host stages developed satisfactorily and were readily available for parasitization. During 1958 and 1959, the major periods of liberation, most of the wasps were reared at Honolulu and sent by air to Australia. To prevent introduction of' unwanted insects, all wasps were immobilized with carbon dioxide for checks of identification at both Honolulu and Sydney. The carbon dioxide treatment had some slightly unfavourable effects which were outweighed by the usefulness of the technique. About 83% of the 583 000 opiine wasps shipped survived to be liberated.
The introduction into Australia of parasites of Listroderes obliquus Klug
Authors: Wilson F , Wearne GR
Published: November 2004

Progress in work aiming at the biological control of Listroderes obliquus is reported. Parasites of this insect were introduced into Australia from Uruguay and Argentina in 1957–68. The species imported were Stomatomyia littoralis (Blanch.) (Tachinidae), Tersilochus argentinensis (Blanch.), and T. parkeri (Blanch.) (Ichneumonidae). The material of parkeri includes two "strains" which may prove to be distinct, species. All species have been liberated, and T. parkeri has been recovered. None of the parasites is yet known to be established, but Tersilochus liberat)ions are continuing. Information is given on the biology of the host, and its parasites.
Interactions between heredity and environment in the Australian Merino. I. Strain X location interactions in wool traits
Authors: Dunlop AA
Published: November 2004

An experiment is described in which five strains of the Australian Merino were run as breeding groups over a number of years in three wool-growing regions. Strain x location interactions were estimated as indicators of adaptation of specific strains to particular environments. The results of the experiment are presented for measurements of greasy fleece weight, clean fleece weight, percentage clean scoured yield, number of fibres per unit area of skin, number of crimps per inch of staple, fibre diameter, and staple length, and for gradings of count (quality number), character, colour, soundness, and handle. Real interactions were found in most of these attributes but they were generally small and accounted for only a minor fraction of the variance. Inconsistency of the interactions in a particular trait may be due to climatic variability from year to year at individual locations. It appears that specific adaptations in these characteristics should not be an important reason for the choice of the strain of sheep to be used in particular areas.
The use of chromium oxide and faecal nitrogen concentration to estimate the pasture intake of Merino wethers
Authors: Lambourne LJ , Reardon TF
Published: November 2004

Statistical analysis of the results of digestion trials on a wide range of fresh pasture herbages shows that their digestibility might be estimated as the intake factor or feed faeces ratio (Y) from the equation: YO.M. = (2.04 – 0.24XN ± 0.186X2N) ± 0.53 where YO.M. is the intake factor for organic matter, and XN is the percentage of nitrogen in faecal organic matter. The results were subdivided arbitrarily into "summer" (September–April) and "winter" (May–August) periods, and these proved to yield significantly different linear equations. The summer regression yielded higher intake factors (corresponding to 2–3% higher digestibility) for a given value of faecal nitrogen percentage. This subdivision reduced the standard deviation from regression only slightly, to about 0.50, which amounts to ± 17% for pasture of 75% digestibility. These equations give considerably lower values of digestibility for a given nitrogen concentration than regressions hitherto published. The present pooled equation, based on short leafy herbage, probably gives sounder estimates for grazing sheep than do the existing equations derived from trials with more mature herbages. When sheep with a wide range in body weight were all fed a maintenance ration, it was found that feed digestibility was not detectably reduced at high levels of feeding. The undoubtedly higher feed intake of grazing than of pen-fed animals, due in large measure to their higher maintenance requirements, therefore may not cause the reduction in digestive efficiency, and thus the bias in estimates of feed intake, that has been supposed. On the basis of the pooled regression, which is felt to be preferable to a subjectively selected "seasonal" equation, estimates of the intake of digestible organic matter (D.O.M.) by sheep in metabolism pens fed on fresh pasture herbage averaged 97 ± 22% of the true figures, or ± 80 g D.O.M.
Appendix 1 - Maximum likelihood estimation of heritability for all-or-none traits in half-sib data
Authors: Brown GH , Tallis GM , Young SSY
Published: November 2004

No abstract available.
Adaptation to subtropical environments by Zebu and British breeds of cattle in relation to erythrocyte characters
Authors: Evans JV
Published: November 2004

Differences in some blood characters between Zebu type cattle, British breeds of cattle, and crosses between these two types are delineated. Zebu type animals tend to have higher packed cell volumes, erythrocyte sodium concentrations, whole blood specific gravities, and gene frequencies for the fast-moving haemoglobin, and lower erythrocyte potassium concentrations and median corpuscular fragilities, than British breeds. The results are discussed in relation to endocrine balance and methods which have been developed for the assessment of adaptation of cattle to tropical and subtropical environments. The concentration of potassium in erythrocytes is suggested as another possible index of adaptation potential in cattle.
Wheat quality: A factor analysis of some test data
Authors: Jardine R , Moss HJ , Mullaly JV
Published: November 2004

Seventeen tests for the measurement of wheat grain samples in respect of bread making quality have been investigated. Two (17 x 17) correlation matrices were calculated from the data yielded by the application of those tests to two series of samples, and factor analyses of those matrices were then undertaken. The analyses indicate that four oblique but relatively independent factors, designated as "strength", "hardness", "stability", and "stiffness", are sufficient to account for the correlations among tests. The two independent sets of data show good agreement as to the factor structures of the tests; and where they differ, reasonable explanations, in terms of either procedures or sample characteristics, are generally available.
The importance of liquid-seed contact during the germination of Medicago tribuloides Desr.
Authors: Sedgley RH
Published: November 2004

At a given matric potential, rates of uptake of water and rates of seed germination on a suction plate apparatus were increased by improving the degree of contact between liquid water and seed. The conclusion of Collis-George and Sands (1962) that small matric potentials, as such, influence the rate of seed germination is critically reviewed in the light of the present investigation. The rate of germination of seeds was not influenced by small pressure potentials, which like matric potentials are a non-osmotic component of the total water potential.
The interrelation of dormancy, size, and hardness in seed of Trifolium subterraneum L.
Authors: Lipp AEG , Ballard LAT
Published: November 2004

Seeds of single samples of each of three cultivars of Trifolium subterraneum L. were separated into size classes. The large- and small-seed classes were further divided into hard and soft seed. The dormancy status of each of these four arbitrary classes was determined. In all samples, lower dormancy was associated with large seed and with soft seed. Possible origins of these associations are discussed in terms of the environments in which the seeds matured.
The application of calorimetry to the study of ruminal fermentation in vitro
Authors: Walker DJ , Forrest WW
Published: November 2004

Techniques evolved for the study of heat production during the metabolism of pure cultures of microorganisms have been adapted for the study of certain aspects of the behaviour of the mixed cultures responsible for fermentation within the rumen. This approach allows whole untreated rumen contents, collected via fistulae, to be studied. The instrument is sensitive to very small changes in the overall evolution of heat, and so is capable of indicating overall changes in metabolic activity. In the samples studied in this series of experiments, the rates of heat and gas (carbon dioxide plus methane) production varied directly with the solids content of the sample. At 24 hr after feeding, the heat produced by ruminal fermentation in the sheep used was calculated to be between 480 and 1360 cal/hr. Ruminal fermentation was not affected by 240 mmoles of volatile fatty acid per litre, but was markedly inhibited by the same level of sodium ion. Lactate ion too appeared to have a specific inhibitory effect. The solid portion of rumen contents was found to possess much greater cellobiose-fermenting activity than did the fluid portion, and lactate accumulated as a transitory intermediate during cellobiose fermentation by whole contents. Small changes in pH had little effect on the course of fermentation in samples collected 16 hr after feeding. These findings and possibilities for the use of calorimetry in the study of complex biological systems are discussed.