bluuebunny/crossref_metadata_2025 huggingface dataset:
The genetic basis of growth, reproduction, and maternal environment in Romney ewes. II.* Genetic covariation between hogget characters, fertility, and maternal environment of the ewe
Authors: Ch'ang TS , Rae AL
Published: November 2004

This paper is the second in a series of studies on the genetic variation and covariation in growth and reproductive characters of the New Zealand Romney sheep. The data used were obtained over a period of 11 years (1955–1965 inclusive) from a random bred experimental flock maintained at Massey University, Palmerston North, New Zealand. Phenotypic correlations were estimated between the ewe's liveweights, oestrous performance at the hogget stage (from weaning to about 14 months), and her subsequent fertility (number of lambs born per ewe) at the first lambing (2-year-old) or over several lambings. These correlations were compared from the viewpoint of accuracy in predicting, prior to first mating, a young ewe's potential fertility over one or several lambings during her own lifetime. The results suggest that for this purpose, the predictive accuracy of the hogget characters is generally low but comparable with, and in some cases, substantially greater than, that obtainable from fertility records belonging to the dam of the young ewe. Three different methods were used to estimate the genetic correlations. In general, the pattern of genetic correlations, either within the hogget characters or between them and fertility of the ewe, is predominantly one of positive values ranging from moderate size to unity. In contrast, most of the maternal genetic correlations were negative. The relative efficiency of indirect versus direct selection for genetic gain in various characters was examined under different assumptions made with regard to the maternal effect. Indirect selection, based on the measurement of hogget (yearling) liveweight or number of hogget oestruses, for genetic gain in fertility of the Romney ewe is expected, on present evidence, to be more efficient than direct selection. Of the two characters, hogget liveweight is likely to find wider application because it can be more easily measured.

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*Part I, Aust. J. Agric. Res., 21: 115 (1970)
Effects of field infestations of gastrointestinal helminths and of the cattle tick (Boophilus microplus) on growth of three breeds of cattle
Authors: Turner HG , Short AJ
Published: November 2004

Approximately equal numbers of Shorthorn x Hereford (British), Africander x British, and Brahman x British yearlings (all F3-F4 generations), totalling 117, were run together on one pasture. One-third of each breed type was dipped every 3 weeks to control ticks, one-third was given injectable tetramizole at the same intervals to control gastrointestinal helminths, and one-third was untreated. The estimated increases in gains in body weight in 27 weeks due to dipping were 10 kg (10%) in Africander cross and 3 kg (3%) in Brahman cross animals (neither significant), but 27 kg (46%) in Shorthorn–Herefords (P 0.001). Anthelmintic treatment increased gains by 22 kg (22%) in the Africander cross (P < 0.001), and 1 kg (1%) in the Brahman cross group (not significant), and 18 kg (30%) in the Shorthorn–Herefords (P < 0.01). The differential breed responses to the presence of ticks were accounted for by differences in the numbers of female ticks maturing. The Africander and Brahman cross animals carried a mean of 20–30 ticks per side ompared with75–100 on Shorthorn–Herefords, and had higher repeatability of counts on individual animals. The regression of weight gain on tick count between animals within infested groups was similar to that between infested and dipped groups. There was no breed difference in counts of helminth eggs in faeces. There were significant differences between animals but they were not correlated with weight gain. Tick burdens were moderately high. Helminth egg counts were low. In these circumstances and under the pasture conditions represented, tick resistance accounted for 40% of the superiority in growth of the Brahman cross or Africander cross over Shorthorn–Herefords, and tolerance of helminths accounted for none of the difference between Africander cross and Shorthorn–Herefords, for 25–40% of the difference between Brahman cross and Shorthorn–Herefords, and for more than the observed difference between Brahman and Africander crosses. The effects of both parasites on growth, and the importance of differential responses of breeds, are conditioned by environmental conditions, notably nutrition.
Effects of the number of spermatozoa and volume of diluted semen on fertility in the ewe
Authors: Entwistle KW , Martin ICA
Published: November 2004

Incidence of pregnancy in artificially inseminated Merino ewes was not significantly affected by dilution of semen with buffered glucose so as to present equal numbers of spermatozoa in different volumes (50 or 200 µI) or by reducing number of spermatozoa per insemination from 100 to 50 million. Respective pregnancy percentages for various volumes and concentrations of semen were: 50 µl, 50 x l06, 48.7%; 200 µl, 50 x l06, 57.1%; 50 µl,100 x l06, 53.8%; 200 µl , 100 x 106 52.9%; 31 µl, 100 x l06 (undiluted control), 60.2%.
The percentage of pregnancies was significantly higher among ewes with clear or heavy (v. light) raddle marks left by the teaser rams used to detect oestrus, and among those with a copious flow of vaginal mucus at insemination. The fertility of all semen fell as the interval between collection and insemination increased to 1 hr.
The influence of cultivar, temperature and photoperiod on post-flowering development of wheat
Authors: Marcellos H , Single W V
Published: November 2004

The duration of post-anthesis development was studied in eight spring wheat cultivars under field conditions. Variation in post-anthesis environment was achieved by varying the date of anthesis through the use of seed vernalization, extended photoperiod, and serial sowing. Multiple correlation and regression analysis of phase duration on temperatures and photoperiod was able to account for 75–97% of the variation in duration of the post-anthesis phase. Differences in the rate of post-anthesis development between cultivars were not statistically significant: nor was the influence of photoperiod significant. Air temperature was the principal factor influencing the rate of development in this phase. Observations of the duration of post-anthesis development taken from field crops in three successive years agreed well (R2 = 75%) with those predicted from the regression relationships previously established. The data are discussed in relation to the implication of the rate of post-anthesis development in yield variation.
Recovery of flue-cured tobacco from magnesium deficiency: changes in leaf magnesium content and effects on leaf quality
Authors: Pinkerton A
Published: November 2004

Twenty-four days after being transplanted into sand culture outdoors, tobacco plants were supplied with nutrient solutions with and without magnesium. Magnesium at two levels was resupplied to some deficiency-stressed plants 6, 11, 16, or 26 days later, and all plants were grown to maturity. The value of cured leaf was affected adversely when the period without magnesium exceeded 6 days. Quality of top leaf, but not of cutters, was improved when resupply was made at the rate necessary for maximum leaf value when supplied throughout. Addition of magnesium at a higher level improved the quality of leaf lower on the stalk, but led to an accumulation of magnesium in top leaf with subsequent impairment of quality. It appeared that the leaf concentration of magnesium had to fall below 0.2% for a period of between 5 and 10 days for leaf deficiency symptoms to appear. The application of magnesium, even at a high rate, upon the appearance of the first symptoms of deficiency resulted in a loss of over 25% in the value per plant.
Single-plant characters as a measure of field plot performance of wheat cultivars
Authors: Syme JR
Published: November 2004

The 49 cultivars in the Fifth International Spring Wheat Yield Nursery (ISWYN) were grown as single plants in pots and 16 characters measured. Grain yield of the cultivars as single plants was not significantly correlated with ISWYN mean grain yields, although there were high correlations between single-plant and field performance in days to ear emergence, height, and 100-grain weight. ISWYN cultivar mean yields were used as the dependent variable in a stepwise regression analysis with the 16 single-plant characters as the independent variables. Harvest index accounted for 71.7% of the variability in ISWYN yields, and days to emergence of leaf 7 and 100-grain weight raised this to 78.5 % in a multiple regression. These results suggest a new, indirect method of predicting relative mean yields of wheat genotypes.
The metabolic excretion and true digestibilities of nitrogen and fat by cattle and sheep with particular reference to forage-faeces relationships
Authors: Moir KW , Swain AJ
Published: November 2004

The non-dietary nitrogen excretion in faeces and the true digestibility of nitrogen determined in 23 digestibility experiments with grasses were respectively 0.60 ± 0.063 g N per 100 g forage organic matter and 84.9 ± 2.29%, when estimated from the regression of digestible nitrogen on percentage dietary nitrogen, and 0.60 ± 0.026 g N and 82.9 ± 2.33%, when estimated from data obtained by separating dietary and nondietary faecal nitrogen with detergent solution. The true digestibility of nitrogen, estimated similarly in four digestibility experiments with legumes, was higher than that in grasses. Among grasses and legumes but not within grasses, digestible organic matter was more closely correlated with non-dietary faecal nitrogen than with total faecal nitrogen. Among and within grasses and legumes the apparently digestible protein was more closely correlated with faecal nitrogen when undigested dietary nitrogen as a proportion of total faecal nitrogen was included as a variate in a multiple regression equation. The endogenous excretion of saponifiable fat was negligible and its average true digestibility estimated from regression analysis was 52. .6 ± 5.55 %.
Varietal differences in in vitro dry matter digestibility in Setaria, and the effects of site, age, and season
Authors: Hacker JB , Minson DJ
Published: November 2004

Six Setaria introductions were grown in small plots at three sites differing in soil type and location in south-eastern Queensland, and fertilizer and irrigation water were applied at similar rates. All plots of each introduction were genetically identical. Three different cutting regimes were imposed, such that at 12-week intervals during the 2 years of the experiment 4, 8, and 12-week regrowth was available for comparison of in vitro dry matter digestibility. There was an overall difference in digestibility between varieties of 6.6 percentage units, and the ranking order was usually the same for all sites, seasons, and ages of regrowth. Three of the introductions were consistently superior to cv. Nandi, the only commercial cultivar included in the present study. The two Setaria splendida introductions ranked second and sixth, although they were both higher in ash concentration than the other introductions, and this was associated with high potassium content. Differences between varieties in digestibility were not associated with flowering differences, despite large differences in flowering behaviour. The maximum mean difference between sites was 4.9 units and this was associated with differences in ash content. Difference in ash content, however, accounted for only 23% of the digestibility difference. The high ash content was associated with high concentrations of potassium. There was no association between nitrogen content and digestibility. The introduction lowest in digestibility had the highest nitrogen content. Digestibility was higher in winter than in summer at all sites, and the extent of this difference increased with age of regrowth. Higher digestibilities were obtained in younger regrowth.
Seasonal changes in sodium and chloride concentration of saltbush (Atriplex spp.) leaves as related to soil and plant water potential
Authors: Sharma ML , Tunny J , Tongway DJ
Published: November 2004

Sodium and chloride concentrations in mature leaves of two Atriplex species, A. nummularia and A. vesicaria, growing on two clay soils were monitored during June 1969 to June 1970. The corresponding soil water content (W-), osmotic potential (π) and matric potential (τ) of soil water, and relative leaf water content (w) were also evaluated. Both the sodium and chloride concentrations in leaves increased progressively with the corresponding decrease in W from September to December, reaching about twice their original values. From December on, sodium and chloride remained relatively stable until April when they started to decline progressively with a steady increase in W. Intermittent rains during summer changed W for short periods, but the leaf salinity remained unchanged. Irrespective of soil, A. nummularia leaves contained more sodium than A. vesicaria, while the reverse was true for chloride. Invariably leaf salinity was strongly correlated with W, τ and π but the correlation with w was significant only for A. vesicaria. Empirical equations fitted to indicate the relation of sodium and chloride to each of the variables and also to multiple regressions of (π τ) and (W, w) are given. Various factors which might be responsible for inducing seasonal variability in the leaf salinity are discussed. It appears that the higher salinity build-up in Atriplex during summer is not only due to increased electrolyte concentration in the growing medium and to high transpiration rates, but is also associated with drought tolerance by these plants.
Influence of the concentration and volume of saline water on the food intake of sheep, and on their excretion of sodium and water in urine and faeces
Authors: Wilson AD , Dudzinski ML
Published: November 2004

The intake of food and the excretion of urine and faeces by 15 Merino sheep were recorded while they were given fixed volumes of fresh or saline (1 -5 and 2.0% sodium chloride) drinking water. The food intakes of the sheep increased as the volumes of either fresh or saline water were increased from 0.5 to 6.0 l/day. The addition of sodium chloride to the water decreased the food intake, but the decrease was restored by an increase in the volume of water given of c. 50 % for 1.5 % sodium chloride, and c. 100% for 2.0% sodium chloride. However, on 2.0% sodium chloride, no further increase in the intake of food occurred with volumes above 3.0 l/day, and maximum intakes were only 6045% of the maximum intakes on fresh water. When the lower volumes of saline water were given, the amount of food eaten for a given volume of water was decreased at higher temperatures and slightly decreased by a higher potassium content of the diet. High volumes (4.0-6.0 l/day) of 2.0% sodium chloride depressed food intake when the ration was oaten chaff, but not when it was lucerne chaff. The increased intake of sodium arising from the addition of sodium chloride to the water was excreted in the urine, and there was no change in the sodium content of the faeces. The concentrations of sodium and potassium in the urine declined as the amount to be excreted was increased. The volume of urine excreted was related to the amount of sodium and potassium to be excreted, while the amount of water lost in the faeces was related to the quantity of faecal dry matter excreted and the type of diet.
Salt tolerance in the wild relatives of the cultivated tomato: water balance and abscisic acid in Lycopersicon esculentum and L. peruvianum under low and high salinity
Authors: Tal M , Gavish U
Published: November 2004

The cultivated tomato Lycopevsicon esculentum and the more salt-tolerant wild species L. pevuvianum were used. Transpiration of whole plants and detached leaves, stomata1 density and opening, and abscisic acid level were measured for the two species grown under both control and saline conditions. Root resistance to water flow and conductivity of guttation fluid were compared only for plants growing in the control solution. Transpiration of whole plants was higher in wild plants grown in the control solution, but decreased more under salinity. Wild plants had fewer stomata per unit leaf area, but these opened wider in the control solution and closed more in the saline solution as compared with the cultivated ones. Root resistance to water flow and conductivity of guttation fluid were higher in the wild plants. The abscisic acid level was higher in the cultivated species and increased somewhat in both plant types under salinity. The significance of these findings in relation to the greater adaptability of L. pevuvianum to stress is discussed.
Illuminance, stomatal opening, and photosynthesis in sorghum and cotton
Authors: Pasternak D , Wilson GL
Published: November 2004

The relationships between illuminance, leaf resistance, and net photosynthesis were studied in sorghum. Some comparisons were made between varieties chosen on the basis of possible differing environmental adaptation, and with cotton whose photosynthetic response is known to differ from that of sorghum. The after-effects of varying periods and degrees of shading were examined for sorghum. Net photosynthesis of sorghum was not light saturated at 11,000f.c. and increases above intermediate illuminance arises almost entirely from increasing stomatal opening. At lower intensities other factors become important, but leaf resistance still exerts the major control. In contrast, leaf resistance in cotton was much lower at all illuminances, and was relatively little affected by changing illuminance. Light saturation of cotton at 5000 f.c. was associated with constant leaf resistance, while at lower intensities, declining net photosynthesis must depend mainly on factors other than stomatal closure. Variation between four sorghum varieties in response to illumination was attributed solely to differences in leaf resistance. Stomata opened slowly after shading at below 3000 f.c., and at a rate independent of the duration of shading. Shading in the afternoon had greater and more persistent effects. Net photosynthesis was affected according to stomatal aperture.
Quantitative control of flowering time in wheat cultivars by vernalization and photoperiod sensitivities
Authors: Syme JR
Published: November 2004

Vernalization sensitivity (V) and photoperiod sensitivity (P) were measured in a range of wheat cultivars by the hastening of development brought about by seed vernalization and long-day treatment, respectively. Using multiple linear regression analysis V and P accounted for 77-94 % of cultivar variation in the time from sowing to ear emergence, or to anthesis, over 19 sowings at three sites. From the regression equations, the optimum combination of P and V for adaptation to variable sowing time was estimated. In two cases this was predicted to be a wheat with high V and low P values. Seasonal changes in the coefficients of the multiple regression equations were related to environmental changes in temperatures and photoperiod.
Productivity of vegetable crops in a region of high solar input. I. Growth and development of the potato (Solanum tuberosum L.)
Authors: Sale PJM
Published: November 2004

Two spring-planted and one summer-planted crops of the potato var. Scbago have been grown under conditions of high solar input (daily averages throughout each experiment 23.1, 22.2, and 13.9 MJ m-2 respectively) in the Murrumbidgee Irrigation Areas of New South Wales. Treatments were a combination of three levels of solar input (0, 21, and 34% shade throughout growth) with two levels of irrigation (soil restored to field capacity at each estimated soil moisture deficit of 2.0 cm or 3.5 cm in two experiments, 3.5 cm or 5.0cm in the other). Growth analyses were made throughout each experiment. Environmental measurements showed little effect of shade covers on air temperature or relative humidity, and occasional measurements of leaf temperature and leaf water potential showed only small differences between shaded and unshaded plants. Differences in leaf and stem dry weights between plants in any treatments were small, but leaf area and stein length increased and specific leaf weight decreased with increasing shade. An increase in shade also decreased the numbers of tubers per stem which developed, and, while it did not influence the time of initiation, the time between onset of initiation and development of maximum bulking rate was greater as shade increased. Bulking rates with no shade were high (up to 1.4 t ha-l day-l) and only slightly less on shaded plots. In the drier of the two irrigation treatments in each experiment bulking rate was only slightly reduced, but the rate of leaf senescence was greater. The treatments did not affect the time of cessation of bulking. The results are consistent with the hypothesis that photosynthesis in the potato is controlled largely by the size of the 'sink' provided by the growing tubers, and it is suggested that the main effect of solar input was in controlling the 'sink' size which developed in the two or three weeks following the onset of initiation. The high growth rates and accelerated ontogeny were probably largely a result of the high temperatures of the region. Final yields are considered in the next paper.
The effect of plant structure on the intake of tropical pastures. II.* Differences in sward structure, nutritive value, and bite size of animals grazing Setaria anceps and Chloris gayana at various stages of growth
Authors: Stobbs TH
Published: November 2004

Bite size (organic matter content per bite) of cows grazing swards of Chloris gayana (rhodes) and Setaria anceps (setaria) regrown for 2, 4, 6, and 8 weeks was measured using oesophageal fistulated animals. Sward canopy structure was measured by stratification into five vertical layers, each 15 cm high; for each layer weights of leaf and stem components were estimated. Chemical composition and in vitro digestibility of plant fractions and oesophageal fistulae samples were determined. Cows grazing the 4 week regrowths of rhodes grass had a larger bite size (0.32 g OM/bite) than when grazing 2 week regrowths (0.27 g OM/bite) when the availability of herbage and leaf material was lowest. Despite a marked increase in herbage yield as the pastures matured (up to 8427 kg/ha) the mean bite size decreased to a mean of 0.15 g OM/bite at 6 and 8 weeks. The bite size of cows grazing setaria pastures was lower than on the rhodes grass pastures but followed a similar pattern. A high density of leaf within the sward (sward leaf density) as well as a low stem content were considered to be the main factors affecting bite size. Setaria and rhodes grass pastures had both low sward bulk densities (a range of 14–96 kg/ha cm) and low sward leaf bulk densities (a range of 12–43 kg/ha cm) compared with temperate pastures. Basal layers of the sward contained more dense herbage (up to 148 kg/ha cm), but sward leaf density was usually less than 80 kg/ha cm and apparently inaccessible.
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*Part I, Aust. J. Agric. Res., 24: 809 (1973).
Leaf appearance rate and associated characters in some Mexican and Australian wheats
Authors: Syme JR
Published: November 2004

Three Mexican cultivars of high yield potential were compared in four field sowings with three Australian varieties of similar flowering time. The cultivars had different numbers of leaves on the main stem, associated mainly with differences in rate of leaf appearance rather than duration of leaf production. The Mexican cultivars produced leaves more quickly throughout growth, and this was repeated under glasshouse conditions. A fast rate of leaf appearance was associated with more spikelets and with faster tillering. Analysis of parental, F1, F2 and backcross populations of one cross showed leaf production rate to be under polygenic control with moderate heritability.
Distribution of a Johnson grass strain of sugarcane mosaic virus in New South Wales and studies of the host range of the Johnson grass and sugarcane strains
Authors: Penrose LJ
Published: November 2004

Sugarcane mosaic virus is widely distributed in New South Wales. It was isolated from 10 species of plants. Twenty-seven native and introduced grass species were susceptible to SCMV by mechanical inoculation. Seventeen new hosts of SCMV were recorded. Of 20 virus isolates from eight host species, only one—from sugarcane—failed to infect Johnson grass. The principal reservoir for sugarcane mosaic virus was Johnson grass.
Nutritional evaluation of meat meals for poultry. VIII.* Nutritive values of and limiting amino acids in cereal diets, supplemented with meat meal
Authors: Skurray GR , Cumming RB
Published: November 2004

When a commercial meat meal was used to supplement wheat, corn and sorghum diets to growing chicks, there was a wide variation in performance. Feed conversion efficiencies were higher on diets based on wheat and corn than those based on sorghum. The nutritive value as determined by chick growth tests of a wheat-plus-meat meal diet was higher than a corn or sorghum-plus-meat meal diet. The nutritive value of a wheat–plus–meat meal diet, supplemented with lysine and methionine, was the same as that of a crystalline amino acid reference diet. The weight gains of chicks given these two diets were higher than those obtained with diets based on wheat, corn and sorghum, not supplemented with lysine and methionine. The results were explained in terms of the limiting and digestible essential amino acids in these diets. The limiting amino acids in the diets were determined from the plasma amino acid levels in chicks given these diets.

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*Part VII, Aust. J. agric. Res., 23: 913-22 (1972).
Inheritance of nutritive quality of summer herbage in Phalaris tuberosa L
Authors: Oram RN , Clements RJ , McWilliam JR
Published: November 2004

Nutritive quality was measured in a genetically diverse population consisting of 55 full-sib families in 16 half-sib groups. The families were grown as pure grass swards and grazed heavily at intervals during the second winter and spring. In early summer, the families differed significantly in crude protein and crude fibre contents and in in vitro digestibility. The heritabilities of these characters were 53.5, 43.0 and 60.4% respectively on a full-sib family mean basis. Phenotypic variances were such that the predicted response to selection for higher protein content was substantial, whereas those for lower fibre and higher digestibility were small. At later harvests environmental variation increased markedly, and family differences, though large, were not significant. The predicted increase in protein concentration in early summer of one percentage unit for each generation of family selection at an intensity of 10% would be accompanied by a decrease in seedling size and a delay in flowering unless countered by opposing selection pressure. Two methods for suppressing the undesirable correlated response in flowering time were found to be equally effective, and a new method was formulated to minimize the number of protein determinations required in subsequent generations. Techniques for sampling mature herbage for nutritional value assessment are discussed.
The importance of environmental factors in soil fertility assessments. I. Dry matter production
Authors: Stefanson RC , Collis-George N
Published: November 2004

The importance of environmental factors on assessments of soil fertility was examined by means of pot experiments in the glasshouse. A preliminary experiment showed, over the course of 12 months of testing, that the fertility ratio varied with the season. In the main experiment each of two soils received nine chemical treatments in an omission-type experimental design. All chemical treatments were subjected to three different light regimes obtained by shading and to three soil temperatures. They were repeated at three different seasons of the year. Plants growing under acute mineral deficiency responded to changes in the environmental conditions and the deficiency became less acute the more the physical conditions favoured plant growth. Changes in environmental conditions were able to eliminate a marginal deficiency of plant nutrient. Because the results show many first and second order interactions between root temperature, light intensity and season, and because of the different yield responses to these factors for different soils and for different nutrients, an assessment of fertility by means of fertility ratios under one set of pot culture conditions cannot easily be applied to other situations.
Water consumption and water turnover of sheep grazing semiarid pasture communities in New South Wales
Authors: Wilson AD
Published: November 2004

The water consumption and water turnover of Merino sheep grazing on three natural pastures of south-western New South Wales were recorded throughout 1 year, and supplementary data on the water consumption of sheep on some pastures were collected for a further 2–4 years. On Danthonia caespitosa grassland, water was consumed for up to 7 months each year over the summer months. Maximum intakes were 3–3.5 litres per sheep per day, but this was reduced for 1–2 weeks after falls of rain of less than 25 mm and for longer periods after heavier falls. The provision of shade reduced water turnover by a maximum of 0.3–0.5 litre per day on some occasions only, which indicates that shade is of little importance to woolled sheep. On the saltbush (Atriplex vesicaria) and belah-rosewood (Casuarina cristata-Heterodendrum oleifolium) communities, water intakes were up to 6–7 litres per day in summer. In the particularly dry summer of 1972–73, water intakes of the sheep on saltbush rose to 12 litres per day for several months. The higher water intakes of these sheep were attributed mainly to the high mineral content of the Atriplex and Bassia spp. eaten by them, although the sheep on the belah-rosewood community were also in a hotter environment. In contrast to the sheep on Danthonia, those on the bush communities consumed significant amounts of water throughout the winter in years of low rainfall.
Relationships among rate and duration of flowering and seed yield components in subterranean clover (Trifolium subterraneum)
Authors: Francis CM , Gladstones JS
Published: November 2004

Time of flowering, duration of flowering, rate of inflorescence production per unit area, viability of seeds harvested 20 and 30 days after anthesis, and seed yield and its components were measured on 24 subterranean clover strains grown as irrigated swards. Seed yield was unrelated to time or duration of flowering, but positively correlated with rate of inflorescence production, total inflorescence, burr and seed numbers, number of seeds per burr, and seed size. Rate of inflorescence production was the main determinant of total inflorescence numbers per unit area and an important determinant of total burr and seed numbers per unit area. It was negatively related to flowering duration, and weakly so to seed size. Seed size was unrelated to strain maturity. Seeds of small-seeded and fast-flowering strains on average attained viability faster than those of large-seeded and slow-flowering strains. Number of seeds per burr increased slightly with lateness of flowering, but was unrelated to seed size or flowering rate. It is concluded that rapid flowering and high seed number per burr should be useful primary selection criteria in selecting subterranean clovers for seed yield and general adaptation in southern Australia.
Studies of fat distribution in the bovine carcass. III.* Influence of intramuscular fat on the weight of total dissected muscle, muscle/bone ratio and the growth coefficients of muscle groups
Authors: Johnson ER , Pryor WJ
Published: November 2004

The influence of intramuscular fat weight on total dissected muscle weight, muscle/bone ratio and the growth coefficients of 'standard muscle groups' was examined in 55 cattle (including foetuses and calves) with total dissected fat contents ranging from 1.3 to 38.9%. Intramuscular fat weight was significantly correlated with total dissected muscle weight (r = 0.97, P < 0.01), percentage total dissected fat weight (r = 0.82, P < 0.01) and age (r = 0.72, P < 0.01). Comparison of two regressions of total muscle weight on total muscle plus bone weight, one based on dissected muscle weight and the other on dissected muscle weight less intramuscular fat weight, showed that neither the slopes nor the intercepts differed significantly. Comparison of two regressions of muscle/bone ratio on muscle plus bone weight, one based on dissected muscle weight and the other on dissected muscle weight less intramuscular fat weight, showed that neither the regression coefficients nor the intercepts differed significantly. Intramuscular fat varied from 0.71 to 7.46% of chilled side muscle weight in carcasses which had total dissected fat contents ranging from 1.3 to 35.1 %. The increase in muscle/bone ratio attributable to intramuscular fat weight over this fatness range varied from 0.02 to 0.38. Comparison between pairs of growth coefficients for each 'standard muscle group', one based on dissected muscle weight and the other on dissected muscle weight less intramuscular fat weight, showed that there were no significant differences.

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*Part II, Aust. J. Agric. Res., 24: 287 (1973).
Root rot caused by Pythium irregulare Buisman, an important factor in the decline of established subterranean clover pastures
Authors: Stovold GE
Published: November 2004

The problem of poor re-establishment and poor seasonal production in long-term subterranean clover pastures has been recognized for some time, particularly on the Southern Tableland and Slopes regions of New South Wales. Field and laboratory investigations showed that rotting of the lateral feeder roots was a common disease of subterranean clover during the cool part of the growing season. Isolations made from diseased roots yielded a predominance of Pythium spp. of which Pythiurn irregulare was the most common. Pathogenicity tests demonstrated that P. irregulare consistently caused damping-off of germinating subterranean clover. This fungus also infected established plants and at low temperatures caused severe reduction of dry matter production. Symptoms produced on artificially inoculated plants were identical with those observed on plants infected in the field. Soil moisture and the level of fungal inoculum added did not have a critical effect on the severity of root disease. A range of other important pasture and crop species were also artificially infected with P. irregulare, with resulting necrosis of feeder roots. In vitro studies of factors affecting the growth of P. irregulare showed that this pathogen was well adapted to survive and cause disease in cold wet soils, the conditions most favourable for root rot in the field. The importance of P. irregulare as a pathogen of established plants and possible means of reducing its effect on the growth of subterranean clover are discussed.
Small-sward testing of Stylosanthes in northern Australia: Preliminary considerations
Authors: Burt RL , Edye LA , Williams WT , Gillard P , Grof B , Page M , Shaw NH , Williams RJ , Wilson GPM
Published: November 2004

An experiment is described in which 27 accessions of Stylosanthes, comprising some seven species, were grown for 3 years in small swards at eight different sites covering a wide range of environments. The accessions used were selected on the basis of previous studies, so as to represent a wide range of species and species forms. Numerical analysis was used to delineate those species, or species forms, likely to be of agronomic value in the various areas. The implications of the methods used and the results obtained are discussed in relation to plant introduction and plant evaluation techniques.
Mineral elements in temperate crop and pasture plants. III.* Copper
Authors: Gladstones JS , Loneragan JF , Simmons WJ
Published: November 2004

Concentrations and total amounts of copper in the tops were measured in 24 varieties of 21 annual crop and pasture species, grown in the field on a lateritic gravelly sand with three levels of copper application and sampled at three growth stages and maturity. Copper applications at the normal commercial rate in Western Australia and at three times this rate did not increase yield. Both rates increased copper concentrations slightly in young plants, but this effect had largely disappeared by flowering. Copper application did not change the relative order of species when ranked according to their copper concentrations. Copper concentrations in the tops declined with age in all species, but at differing rates. All species continued to accumulate copper up to harvest 3 (near maturity), with the exception of lupins which suffered net losses from the tops after flowering. Species varied greatly in their copper concentrations. In cereals and grasses, copper concentrations increased linearly with increasing nitrogen contents, with a tendency towards higher copper/nitrogen ratios as concentrations of both elements increased. Legumes had higher copper concentrations than grasses and cereals, especially late in the growing season, but lower and more variable copper/nitrogen ratios. Within taxonomic groups, species adapted to sandy and copper-deficient soils tended to have the highest copper concentrations and copper/nitrogen ratios, and to translocate most copper to the seeds.

*Part I, Aust. J. Agric. Res., 18: 427 (1967); Part II, Aust. J. Agric. Res., 19: 353 (1968).
Influence of water stress on parameters associated with herbage quality of Panicum maximum var. trichoglume
Authors: Wilson JR , Ng TT
Published: November 2004

Plants of Panicum maximum var. trichoglume grown in soil in pots under a controlled environment were subjected to water stress and the effect on forage quality was assessed. Stress was applied as a series of drying and re-wetting cycles, and harvests of total laminae, stem, root, and also specific laminae, were taken 5, 10, 17, 27 and 57 days after the commencement of stress treatment. When compared with control plants of similar chronological age, the dry matter digestibility (estimated by an in vitro technique) of the stressed plants was lower in leaves 4, 6 and 8, similar in total green laminae and in leaves 10 and 12, and higher in stem and dead laminae. The cell wall content of various tissues of the stressed plants was lower than that of the controls. Water stress delayed stem elongation and flowering. It is postulated that stress also delayed the normal ontogenetical changes of the leaves. If comparison was made on a physiological age basis then stress markedly lowered the dry matter digestibility but had little effect on the cell wall content. The broader implication of delayed ontogeny is briefly discussed. The decrease in dry matter digestibility in stressed plants was not associated with changes in the proportions of cellulose, hemicellulose or lignin, but reflected a decline in digestibility of cell wall material.
The response to phosphate of two annual pasture species. II.* The specific rate of uptake of phosphate, its distribution and use for growth
Authors: Barrow NJ
Published: November 2004

Subterranean clover and Wimmera ryegrass were grown in pots at a range of levels of applied phosphate for up to 33 days after emergence. From the results of sequential sampling, the rates of uptake of phosphate, its distribution and its effect on the rate of assimilation were calculated. The assumption involved in the widely used approximate method for calculating the average specific absorption rate (SAR) of nutrients by roots was found to be invalid. Hence instantaneous values of SAR were calculated from multiple regressions which allowed the simultaneous determination of the effects of phosphorus level and of time. For both species, SAR increased until about 2 weeks after emergence, and then declined. The effect of level of application on SAR differed between the species. For the ryegrass, SAR increased with phosphate level and reached a maximum value. For the clover, there was a level of application below which phosphate was almost ineffective. Above this level, the slope of the relationship between SAR and phosphate applied increased with increasing level of phosphate. It is suggested that this upward-curving relationship occurred because the proportion of added phosphate in the soil solution increases with increasing phosphate level. There was no evidence of a maximum value of SAR for the clover within the range of levels of phosphate used. At all levels of application, the SAR for the clover was lower than that for the grass. Ryegrass transferred a greater proportion of the phosphate to the tops than did clover. The net photosynthetic effectiveness of the tops of both species increased with phosphate concentration. The ryegrass had higher values for photosynthetic effectiveness than the clover at high phosphate concentration. At low phosphate levels the ryegrass allocated a greater proportion of its growth to roots than did the clover.

*Part I, Aust. J. Agric. Res., 26: 137 (1975).
Studies in ovine fertility in agricultural regions of Western Australia : ovulation rate, fertility and lambing performance
Authors: Lindsay DR , Knight TW , Smith JF , Oldham CM
Published: November 2004

A total of 29,500 ewes, of which 2049 were laparotomized, in 53 flocks were used to determine the extent by which variations in body weight and age of the ewes and the temperature and day length about the time of mating were associated with the number of ovulations per 100 ewes (ovulation rate) and reproductive performance of sheep in south Western Australia. Overall there were only 113.7?2.2 ovulations per 100 ewes in the flocks studied. Less than 3% of the ewes failed to ovulate, so that in general differences between flocks were due to differences in the rate of multiple ovulation. Flocks with high ovulation rates produced more lambs per 100 ewes. There were about six extra lambs per 100 ewes for every 10% increase in the ovulation rate. About 40% of these extra lambs were due to extra twins; the remainder were due to more ewes lambing. Both age and body weight of the ewes were significantly correlated with ovulation rate (r = 0.41, P < 0.01 and r = 0.42, P < 0.01, respectively) and all the parameters of reproduction studied. Each 5 kg difference in body weight was associated with 5.9 extra ovulations per 100 ewes (P < 0.01).
Growth of pasture species on the Northern Tablelands of New South Wales
Authors: Lazenby A , Lovett JV
Published: November 2004

The production of herbage by five pasture species—Phalaris tuberosa (phalaris), Festuca arundinacea (tall fescue), Lolium perenne (perennial ryegrass), Trifolium repens (white clover) and Medicago sativa (lucerne)—was measured when they were grown in the field in monoculture, and by phalaris and white clover when grown in mixture. The plots were irrigated to prevent water deficits, and five levels of nitrogen were included; the mixture was also grown under dryland conditions. All plots were defoliated at intervals during a period of 3 years. A capacitance probe was used in an attempt to determine harvest times more objectively, and to establish long-term relationships between meter readings and components of plant yield. Major differences in production were detected between the species, lucerne producing most in the first 2 years of the experiment. Nitrogen and available soil moisture affected both production and botanical composition, and significant differences were detected in species' responses to applied nitrogen and in nitrogen recovery. The performance of lucerne and tall fescue suggests that both species deserve to be more widely grown on the Northern Tablelands of New South Wales.
Studies of weaner sheep during and after a period of weight stasis. II.* Body composition
Authors: Searle TW , Graham NMcC
Published: November 2004

Wether sheep (4 months old) were held at 20 kg liveweight by restricted feeding for either 4 or 6 months and then fed ad libitum. Body composition (total water, fat and protein) was estimated monthly from tritiated water (TOH) space measured in vivo, and on three occasions representative animals were slaughtered, minced and analysed. Composition at any given body weight was compared with that previously determined for animals grown without restriction (controls). Sheep slaughtered at the end of the period of weight stasis contained less protein and more water than the controls but contained a similar weight of fat. Previously derived prediction equations estimated water correctly from TOH space in these undernourished sheep, but protein was overestimated by 0.38 kg (17% of the mean) and fat was underestimated by 0.19 kg (10% of the mean). The body composition of animals slaughtered after partial or complete recovery of weight for age was normal for their weight and predictions were accurate. The sequential estimates of composition indicated that although the relationship between fat and weight differed between individuals, at any given body weight above 32 kg compensating animals and controls had a similar composition.

*Part I, Aust. J. Agric. Res., 26: 343 (1975).
Biological control of Eutypa armeniacae. III.* A comparison of chemical, biological and integrated control
Authors: Carter MV , Price TV
Published: November 2004

The protection of pruned apricot sapwood by benomyl, Fusarium lateritium and a combination of benomyl and F. lateritium against invasion by E. armeniacae was evaluated and compared in field experiments. All treatments gave highly significant control of the pathogen. In vitro tests showed that benomyl and F. lateritium were supplementary in their mode of action, and suggested that integrated control employing both agents will be more useful than either one alone.

*Part II, Aust. J. Agric. Res., 25: 105-19 (1974).
Methionine supplementation of milk proteins for preruminant lambs. II.* Effect on wool growth, liveweight gain and body composition
Authors: Walker DM
Published: November 2004

Twenty-six crossbred lambs in two equal groups, aged 2-5 days, were given a low protein diet based on cows' milk, with or without a supplement of DL-methionine, for an experimental period of 21 days. Intake of gross energy ranged from 518 to 1276 kJ/day per kg0.73 Nitrogen and sulphur retentions were estimated by balance methods and nitrogen retention was also ascertained by comparative slaughter. In the group supplemented with methionine the apparent digestibility of sulphur increased significantly, but there were no significant differences between the groups in the apparent digestibilities of dry matter and nitrogen or in gross energy. Retention of nitrogen and sulphur in the body tissues and in the wool increased significantly. There was a significant increase in wool growth and in the sulphur content of wool, but not in the nitrogen content. Methionine supplementation had no significant effect on liveweight gain. The gain in empty liveweight of the supplemented lambs comprised significantly more protein and significantly less fat than that of the unsupplemented lambs.

*Part I, Aust. J. Agric. Res. 26: 673 (1975)
Measurement in vivo of rumen microbial protein synthesis
Authors: Walker DJ , Nader CJ
Published: November 2004

A method is described for the measurement in vivo of ruminal microbial protein synthesis. The method depends upon the incorporation into microbial protein of sulphur derived from 35S -labelled inorganic sulphate infused continuously into the rumen. Steady-state labelling of rumen digesta protein and specific activity of microbial sulphur are used, along with estimates of total digesta mass, to calculate total microbial sulphur in the rumen. The rate of disappearance of isotope from the rumen after cessation of [35S]sulphate infusion is used to calculate the flow rate of microbial s~dphur from that organ. Microbial sulphur may be used to estimate microbial nitrogen or crude protein by means of conversion factors.