bluuebunny/crossref_metadata_2025 huggingface dataset:
Factors limiting the intake of feed by sheep. VIII.* The roughage requirement of the ruminant lamb fed on concentrate diets based on wheat
Authors: Weston RH
Published: November 2004

The voluntary feed consumption (VFC) and body weight gain of lambs initially 12 weeks old and weighing 22 kg were measured when diets based on whole wheat grain and varying in straw content were offered. The basal diet comprised, on an organic matter (OM) basis, about 82 parts whole wheat grain and 18 parts protein concentrate; ground wheaten straw was added to provide diets with 2%, 7% or 13% straw. Daily VFC, expressed in relation to body weight in kg0.75 (BW0.75), increased from 85.6 with 2% straw through 90.4 with 7% straw to 94.2 with 13% straw. The corresponding OM digesti bilities were calculated to range from 84.8 to 77.6%. However, the intake of digestible OM and the rate of body weight gain were not affected by the straw content of the diet, the respective mean values for all lambs being 73g/day BW0.75 and 293 g/day. Lambs initially 25 weeks old and weighing 38 kg were offered a diet (2% straw) based on wheat in which the wheat was presented either as whole grains or in ground and pelleted form. With the whole grain diet the daily rates of OM intake, digestible OM intake and body weight gain were 75.6 g/ BW0.75, 64.7 and 254 g respectively; the corresponding values with the ground grain diet were about 20% lower. Studies involving the slaughter of animals showed that a large proportion of the wheat grain consumed reached the rumen in the form of whole grains and these contributed significantly to the dry matter of the ruminal digesta. The rate of ruminal digestion of whole wheat grains was slow (37% in 96 hr) when the sheep were given a diet based on wheat. By contrast, when a roughage diet was consumed the rate was high (81% in 96 hr). Fractured grain was rapidly digested in the rumen (67% in 20 hr). The mean residence time of water-soluble marker in the rumen and the rate of digesta flow from the rumen were greater in fistulated sheep given a whole grain diet than with a ground grain diet. The diets also differed with respect to the concentration of potassium in rumen liquor, the rumen potassium pool size and the rate of flow of sodium and volatile fatty acids to the omasum. It was concluded that the roughage requirement of the ruminant lamb fed on concentrate diets based on whole wheat did not exceed the equivalent of 2 g ground straw per 100 g diet. The possibility of a higher roughage requirement with ground wheat diets is suggested.

___________________
*Part VII, Aust. J. Agric. Res., 24: 387 (1973).
Fusarium avenaceum, a seed-borne pathogen of subterranean clover roots
Authors: McGee DC , Kellock AW
Published: November 2004

Fusarium avenaceum (Corda ex Fr.) Sacc. has been shown for the first time to be a seed-borne pathogen of subterranean clover (T. subterraneum L.). In laboratory tests symptoms of subterranean clover root rot occurred on plants grown from infected seed. F. oxysporum (Schlecht.) also was seed-borne. It was only weakly pathogenic, although isolated more frequently from diseased roots than F. avenaceum. Pythium sp. was not detected on seed and rarely isolated from roots of diseased field plants, but it was highly pathogenic to subterranean clover roots in laboratory tests. F. avenaceum was detected in 81 out of 85 seed lines tested, which comprised 11 cultivars, from four Australian States. Infection with F. avenaceum occurred on up to 27% of the seed in a sample. An application of benomyl (0.63 g/kg seed) controlled seed infection.
Analysis of the nature of interference between plants of different species. II.* Nutrient relations in a Nandi Setaria and Greenleaf Desmodium association with particular reference to potassium
Authors: Hall RL
Published: November 2004

The experimental design and mathematical procedures of de Wit were applied to a study of the influence of potassium level on the growth in monocultures and mixtures of the tropical pasture species Setaria anceps cv. Nandi and Desmodium infortum cv. Greenleaf. When de Wit's approach was extended to include an analysis of nutrient uptake data in conjunction with the dry matter yield responses of the two species, the causal factors in both competitive and non-competitive interference were able to be identified. By this technique it was confirmed that, at a low level of potassium, the Setaria severely restricted the growth of the legume Desmodium by competing for potassium. The Setaria itself grew considerably better in mixtures than in monoculture, and at a high level of potassium did so without detriment to the associated legume. This latter was shown to be a non-competitive effect reflecting the partial independence of the two species with respect to their sources of nitrogen.

___________________
*Part I, Aust. J. Agric. Res., 25: 739 (1974).
Nutrient responses of an indigenous Poa tussock and Lolium perenne L. grown separately and together in pot culture
Authors: Fisher HJ , Myers LF , Williams JD
Published: November 2004

In the first of two glasshouse experiments, Lolium perenne and Poa labillardieriwere grown separately with three levels of nitrogen, four levels of phosphorus, four levels of sulphur and two levels of potassium in all factorial combinations. There were no major differences in the relative responses of the two species. The root/shoot ratio of Lolium was twice that of Poa at the final harvest. Uptake of sulphur was higher in Lolium at high levels of applied sulphur. In the second experiment, Lolium and Poa were grown in pure and mixed culture at five levels of applied nutrients. Grown alone the yields of both grasses were similar to the first experiment but in mixed cultures the shoot yields of Poa were reduced to 20% of those in pure culture. The success of Lolium was attributed to its larger seed and more rapid early growth. Normally Poa increases in size and numbers to dominate natural grasslands if superphosphate fertilizer is applied and white clover develops. The results suggest that the dominance of Poa in these grasslands could be restricted by establishing a vigorous stand of Lolium at the beginning of arable pasture improvement.
Bos indicus and Bos taurus crossbred dairy cattle in Australia. III.* A climate room test of heat tolerance used in the selection of young sires for progeny testing
Authors: Allen TE , Donegan SM
Published: November 2004

A heat tolerance test for cattle is described, and the results of its use over a 7 year period in a largescale breeding program are given. Animals were subjected to the test on up to three occasions, each test comprising 1 week in an anteroom at moderate temperature followed by 5 days in a climate room at high temperature. Measurements of sweating and respiratory rates, rectal temperature and feed and water consumption are given. The animals were ranked by means of a total score which was made up of the' sum of a sweating rate score and feed intake score less the sum of a rectal temperature score and respiratory rate score. A significant Spearman's rank correlation coefficient of 0.67 was obtained between the ranking of 44 heifers in two separate series of tests. Comparison of bulls from dams selected and unselected for milk production in a stressful climate showed the bulls from the selected dams to be superior in heat tolerance. In the large-scale breeding program, the test selected bulls with three-eighths or half Bos indicus blood in preference to those with quarter Bos indicus blood; and within the quarter-breds it selected those out of dams bred in herds located in a stressful environment in preference to similar crossbred bulls out of dams bred in a temperate environment.
Agronomic studies on pigeon pea (Cajanus cajan (L.) Millsp.) III.* Responses to defoliation
Authors: Akinola JO , Whiteman PC
Published: November 2004

Two early-maturing and two late-maturing accessions of Cajanus cajan grown in the field for 161 days were defoliated to 90 cm 'stubbles' every 4,8,12 or 16 weeks over a period of 72 weeks. Evidence from total and seasonal dry matter and nitrogen yields, stand survival, and stubble yield at the termination of the experiment suggested that 8- and 12-week defoliation frequencies could be successfully integrated to incorporate cattle grazing and forage and seed production into a single management system. The late-maturing accessions were shown clearly to be better adapted to cutting, provided that basal green leaves always remained on the stubble. Defoliation of the accession UQ50 to reduce plant height to facilitate subsequent harvesting led to a reduced annual seed yield. The first seed crop was lost, as 'topping' removed the reproductive material.
Studies on the susceptibility of varieties of apple to the feeding of two strains of woolly aphis (Homoptera) and relation to the chemical content of the tissues of the host
Authors: Sen Gupta GC , Miles PW
Published: November 2004

Two strains of woolly aphis have been demonstrated in South Australia, the one ('Blackwood strain') able to attack varieties of apple resistant to the other ('Clare strain'). Both strains display well-defined differences in the ease with which they can colonize different varieties of apple and different parts of any one variety. These differences tend to be related to the composition of the tissues with respect to α-amino nitrogen and phenolics, but the most clear-cut correlation is an inverse one between the susceptibility of tissues and the ratio of phenolics to α-amino nitrogen in the tissue.
Some effects of casing soil amendments on mushroom cropping
Authors: Nair NG , Hayes WA
Published: November 2004

Addition of compost fully colonized by mycelium of Agaricus bisporus (spawn-run compost) to casing peat on mushroom beds resulted in earlier initiation and development of sporophores, more uniform distribution of sporophores, significantly higher yield of mushrooms and early completion of cropping compared with unamended casing peat. Numbers of pseudomonads were also significantly higher in the amended than in the unamended series. Similar results were obtained by substituting equivalent amounts of an inert material such as woven glass fibre for the spawn-run compost. These observations are explained as being due to the interaction between the degree of aeration of the casing peat and the activity of pseudomonads in that layer. A relationship between high levels of pseudomonads and high yield of mushrooms is established. It is pointed out that this technique bears good prospects for increasing the production of mushrooms in commercial farms.
The effect of formaldehyde treatment of a concentrate diet on the passage of solute and particle markers through the gastrointestinal tract of sheep
Authors: Faichney GJ
Published: November 2004

Crossbred wether sheep, each fitted with a cannula in the rumen, abomasum and terminal ileum, were given a concentrate diet either untreated or treated with formaldehyde. A bolus of digesta containing two soluble markers, one of which remained in solution ( 51Cr-EDTA ) , while the other was adsorbed onto particulate matter (103Ru-P), was introduced into each sheep: first into the terminal ileum, then into the abomasum and finally into the rumen. After each dose, faeces were collected at short intervals until all marker had been excreted and mean retention times were calculated from the time course of marker excretion. 103Ru-P was retained much longer than 51Cr-EDTA in the stomach; this was due mainly to retention in the rumen, but 103Ru-P was also retained longer in the abomasum. The mean retention times of 103Ru-P and 51Cr-EDTA in the hind gut did not differ. Formaldehyde treatment of the diet decreased mean retention times in the rumen and in the hind gut, but increased them in the abomasum and small intestine. The markers were fully recovered; 103Ru-P was found entirely in the faeces whereas 4.9% of the dose of 51Cr-EDTA was absorbed and appeared in the urine. The absorption of 51Cr-EDTA from different sections of the gastrointestinal tract appeared to be related to sectional mean retention time.
Metabolic studies on daily and weekly feeding of ruminants given all-wheat diets. I. Digestibility and nitrogen balance in sheep
Authors: Watson MJ , Leng RA , McClymont GL
Published: November 2004

Aspects of digestion and metabolism in sheep fed individually with an all-wheat ration at a rate of either 300 g each day or 2100 g once each week have been investigated. Five digestibility and nitrogen balance trials were carried out over a 13-week period. Sheep on the weekly feeding regimen consumed 50% and 85% of their ration by the end of days 1 and 3 respectively. Both water intake and urine volume were higher on the weekly feeding regimen, but water intake was highest at the beginning of the feeding cycle, while urine volume was highest towards the end. The mean liveweight, digestibility and nitrogen balance were similar in sheep on both daily and weekly feeding regimens. In sheep fed weekly the excretion of nitrogen varied between days within the balance period. When they were first introduced to this feeding pattern the sheep retained less nitrogen than after an adaptation period.
Response to selection in Australian Merino sheep. VI. Inheritance of abnormal staple crimp; estimates of phenotypic and genetic parameters
Authors: Jackson N , Chapman RE
Published: November 2004

The heritability of abnormal crimp in wool at various ages and the genetic and phenotypic cotreiations of crimp abnormality with several wool and body characters were estimated for Peppin Merino sheep. When examined by half-sib analyses of variance, the heritability of abnormal crimp scored at ages less than 4.5 years was low, whereas abnormality at 5.5 years and older was highly inherited. Heritabilities estimated by intra-sire dam-daughter regression analyses with fewer degrees of freedom did not show such a clear-cut pattern, although the estimates tended to increase with age. The genetic correlations of crimp abnormality scores at ages up to 4.5 years with scores at older ages were mainly low. Crimp abnormality scores at most ages had genetic correlations with wool and body characters at 15–16 months of age as follows: strong positive with fibre diameter, weak positive with greasy and clean wool weight, wrinkle score and staple length, and weak negative with fibre number. Genetic correlations with body weight, percentage clean yield, face cover score and crimp frequency were inconsistent. The phenotypic variance of crimp abnormality increased with age, owing almost entirely to an increase in the additive genetic variance. The environmental variance was approximately the same at all ages. Phenotypic correlations among crimp abnormality scores were generally higher between scores at close ages, and particularly at older ages. Crimp abnormality scores at all ages had positive phenotypic correlations with fibre diameter and wrinkle score and negative correlations with fibre number per unit area of skin and percentage clean yield.Crimp abnormality at old ages also had positive phenotypic correlations with greasy and clean wool weights. Environmental correlations of crimp abnormality with greasy wool weight, clean wool weight body weight and fibre number per unit area of skin were negative, and those with percentage clean yield and fibre number positive. Predicted correlated responses in crimp abnormality differed in some respects from correlated responses observed previously in groups of Peppin Merino sheep selected for high and low values of percentage clean yield, clean wool weight, fibre number per unit area of skin and fibre diameter. Methods of selection of sheep which would be expected to reduce crimp abnormality are outlined.
Physiological responses of semiarid grasses. III.* Growth in relation to temperature and soil water deficit
Authors: Christie EK
Published: November 2004

The optimum temperature for vegetative growth of mulga grass was about 25°C, and for Mitchell and buffel grasses 30°. Buffel grass had the highest yield at all temperatures, partly because of its higher growth rate which in turn can be ascribed to both a higher net assimilation rate and the diversion of a greater proportion of dry weight into leaf area. Seedlings with an ample supply of phosphate had higher relative growth rates than phosphorus-deficient seedlings at the commencement of the soil drying cycle, but their growth rates declined more rapidly as the soil water potential fell. This decline was associated with a reduction in the rate of phosphate absorption as well as a decrease in the tissue phosphorus concentration.

*Part II, Aust. J. Agric. Res., 26: 437 (1975).
Response of newly planted peach and apple trees to superphosphate
Authors: Taylor BK
Published: November 2004

The response of peach and apple trees to added superphosphate was recorded both in the nursery and later in the orchard after transplanting. The peach and apple trees responded positively to phosphate applications in both the nursery and the orchard despite the initial presence of medium to high phosphate levels in the soils. Of major interest, too, was the absence of a consistent interaction between the phosphate treatments applied in the separate years. This suggested that the trees could not accumulate enough phosphorus in any one year to influence their response to further phosphate. Leaf analysis showed two important effects in relation to the phosphate treatments. Firstly, since high rates of application of fertilizer led to only small increases in the levels of phosphorus in the leaves, tree growth rate and phosphate absorption rate are apparently closely coupled. Secondly, the deliberate withholding of phosphate fertilizer from all trees in the fourth season led to a marked decline in the levels of phosphorus in the leaves of both peach and apple, which suggested that phosphate fertilizer should be applied annually to young fruit trees. With apple, but not peach, increasing the rate of phosphate applied in the third season stimulated the number of flower buds initiated, but this effect was not simply the result of increased vegetative growth. On the other hand, phosphate application to the peach trees in the orchard resulted in a positive fruit set and yield response in the absence of any tree growth response.
Persistence of benomyl in pruned apricot sapwood
Authors: Price TV , Carter MV
Published: November 2004

The persistence of benomyl in pruned apricot sapwood was investigated. The amount of fungi toxicant recovered from sapwood after application of 5 µg benomyl to the pruned surfaces varied at different times of the year between 90 and 25% when sampled after 2 hr and between 45 and 15% when sampled after 15 days. The amount of fungi toxicant recovered after applications of 25, 50 and 500 µg benomyl varied between 100 and 17% when sampled after 2 hr and between 67 and 12% when sampled after 15 days. No fungi toxicant was detected in bark or sapwood 0.5 cm below the treated surface or in untreated stems. Thin-layer chromatography revealed that the fungi toxicant assayed was MBC (methyl benzimidazole-2-yl carbamate).
Paralysis of cattle by Ixodes holocyclus Neumann
Authors: Doube BM , Kemp DH
Published: November 2004

The number of engorging female Ixodes holocyclus needed to induce paralysis in young cattle was investigated. One or two females were insufficient to paralyse 2–3-week-old unexposed calves but 10 caused paralysis. Older unexposed calves weighing 80-160 kg were not paralysed by up to nine females whereas 20 caused paralysis. Nine out of 10 calves which were paralysed subsequently died. Calves which survived were infested with at least 25 females, a number sufficient to paralyse an unexposed calf. Only two of 11 infestations caused paralysis and no calves died. Tick development was significantly inhibited on these calves and this may partly account for the protection from paralysis.
The analysis of reproductive records with use of labelled sequences and its application to a grazing experiment
Authors: Williams WT , Edye LA
Published: November 2004

A new method is described for analysing sequential results from animals in a reproductive situation. The elements of each sequence are labelled according to whether the animal is pregnant or not, and lactating or not; the resulting labelled sequences are used for analysis, and animals are compared only when they are in the same state at the same time. It is suggested that such a method obviates the necessity for correcting for the weight of the foetus, and thus enables animals which are not in exact reproductive synchrony to be directly compared. The method involves the computation of a dissimilarity matrix, which can be subjected to classificatory or ordination techniques and subsequent statistical analyses.

The method is applied to a grazing experiment in the dry tropics, and is shown to produce novel and informative results. The fertility and seasonal changes in liveweight of cows grazing a Townsville stylo-spear grass pasture were examined over 32 months. There were four randomized blocks of six treatments, which were factorial combinations of two stocking rates and three rates of superphosphate.
Superphosphate significantly affected fertility and liveweight, and the highest fertility was obtained at the intermediate fertilizer rate. Stocking rate affected liveweights only. There were greater liveweight differences between the four reproductive states than between treatments within a reproductive state. The largest treatment differences occurred in nonpregnant, non-lactating cows grazing fertilized as against unfertilized pastures.
The nutritive value for dairy cows of silage made from formaldehyde-treated herbage
Authors: Valentine SC , Radcliffe JC
Published: November 2004

Formaldehyde-prepared silages and untreated silage were made from grass-clover herbage and offered to dairy cows. Formaldehyde was applied at 0.6 and 1.2% of the dry matter of the herbage. The 1.2% formaldehyde-prepared silage had significantly lower concentrations of ammonia nitrogen, total organic acids and propionic acid than untreated silage, but a higher concentration of lactic acid. The 0.6% formaldehyde-prepared silage had a similar degree of fermentation to untreated silage, but more lactic acid and less butyric acid were produced. Treatment with formaldehyde significantly reduced the in vitro digestibilities of dry matter and nitrogen. Cows offered the formaldehyde-prepared silages had significantly greater ad libitum dry matter intakes, produced significantly more milk, protein, butterfat and solids not fat (SNF), and utilized digestible energy more efficiently for milk production than cows offered untreated silage. Differences between treatments in the percentages of butterfat, protein and SNF in milk from cows offered the silages were generally not significant. Treatment with formaldehyde was a suitable method of controlling the ensiling fermentation to Increase the ad lib. dry matter intake and the production of milk and milk components by dairy cows.
Attraction of Aphodius tasmaniae Hope to skatole
Authors: Osborne GO , Penman DR , Chapman RB
Published: November 2004

Skatole (3-methylindole) has been shown to be a chemical attractant for the Tasmanian grass grub beetle Aphodius tasmaniae. There is a similarity in responses by this insect to skatole and to light. This suggests that unfed gravid females will respond positively to both light and dung.
The phosphorus nutrition of the apple tree. I. Influence of rate of application of superphosphate on the performance of young trees
Authors: Taylor BK , Goubran FH
Published: November 2004

A pot experiment was established to determine the influence of rate of superphosphate (applied at planting only) on the growth and fruiting responses of young apple trees (Jonathan/3428) in four successive growing seasons. Increasing the rate of application of superphosphate stimulated tree growth, fruit set and yield over much of the range tested. A critical leaf phosphorus value of 0.32 % in mid-shoot leaves in midsummer is suggested for newly planted apple trees. Phosphate-deficient trees showed delayed bud burst and a retarded rate of development of a reduced number of vegetative and floral meristems. The pronounced effect of phosphorus level on percentage fruit set was also at least partially attributable to its effect on the rate of flower cluster emergence since delayed emergence reduced the opportunity for cross-pollination and fruit set. Fruit from phosphorus-deficient trees contained fewer but larger cells than fruit from non-deficient trees. These results are consistent with the hypothesis that phosphorus level is an important regulator of the meristematic activity of apple tree tissue. Leaves and fruit on phosphorus-deficient trees showed comparatively early senescence. It is suggested that retarded bud development on deficient trees in spring and early senescence of deficient tissues in autumn could result from reduced cytokinin production by deficient trees. Leaf analysis was superior to fruit analysis as an index of the phosphorus status of apple trees. Fruit phosphorus values tended to be constant with time for a given treatment, but leaf phosphorus values declined with time and progressively more of the trees in the low phosphorus treatments developed visual symptoms of phosphorus deficiency. Analysis of soil each year proved of little value as a predictor of the phosphorus status of the trees, since deficiency symptoms were seen on trees grown in soil containing over 1000 ppm phosphorus. Magnesium deficiency symptoms developed on trees in the high phosphorus treatments, and the possible reason for this is briefly discussed.
Response of teat enzymes of sheep and cattle to stimulation by stilboestrol and oestrogenic subterranean clover
Authors: Smithard R , Cole ER , Kennedy JP
Published: November 2004

The activities of glucose-6-phosphate dehydrogenase (G-6-PDH), malate dehydrogenase (MDH) and isocitrate dehydrogenase (ICDH) were investigated as indicators of oestrogenic response in sheep and cattle. The activities of the enzymes were higher in teat tissue from wethers and steers injected with stilboestrol dipropionate than in control groups not receiving oestrogen. There was a positive linear relationship between teat enzyme activity and log(dose + 1) in wethers injected with stilboestrol dipropionate over the dose range 0–40 µg/day. G-6-PDH and MDH were used to detect oestrogenic responses in sheep and cattle to feed containing a high proportion of subterranean clover (Trifolium subterraneurn L.) cv. Dwalganup. The differences in mean enzyme activities between treatment and control groups were highly significant. The results indicate that in the short term, teat enzymes of cattle respond to oestrogenic feeds in a manner similar to those of sheep.
Whole wheat grain feeding of lambs. V.* Effects of roughage and wheat grain mixtures
Authors: Bigham ML , McManus WR
Published: November 2004

Two slaughter trials were conducted with lambs to evaluate the effects on production and some rumen characteristics of the addition of low quality roughage (wheaten straw) and a high quality roughage (pelletized ground lucerne) to wheat grain diets. In the first trial one group of lambs was given a 1/1 mixture of whole wheat grain and chaffed wheaten straw and another chaffed lucerne hay ad libitum. Lucerne-fed lambs had significantly (P < 0.001) higher dry and organic matter intakes, grew faster and had higher levels of volatile fatty acids in their rumens than lambs offered the mixed ration, although there were no differences between rations in dry and organic matter digestibilities. The apparent nitrogen digestibility of the mixed ration was significantly (P < 0.001) lower than that of the lucerne ration. Of lambs offered the mixed ration, 46% had extensive lesions on the ventral wall of the rumen at slaughter, and these were associated with marked inappetence and loss in liveweight. In the second trial comparisons were made of diets consisting of lucerne (either alone or mixed with cracked wheat) and whole wheat grain + limestone. The effect of treating the lucerne with formaldehyde was also studied. There were no significant differences in carcass gain with the lucerne diets; parakeratosis developed in some animals on lucerne-wheat diets but did not affect productive performance. The animals offered whole wheat lost weight, two died of wheat poisoning, and several animals developed lesions on the rumen wall.

_________________
*Part IV, Aust. J. Agric. Res., 26: 729 (1975).
The development of ruminant digestion in the calf. I. The digestion of barley and soya bean meal
Authors: Leibholz J
Published: November 2004

Four male Friesian calves were fitted with re-entrant duodenal cannulae within 1 week of birth. To 5 weeks of age the calves were given milk, then weaned over 2 days and offered a diet containing 60% barley, 20% soya bean meal and 15% wheat chaff. Total collections of digesta flowing to the duodenum after weaning were made for 12-hr periods at weekly intervals for 8 weeks. Of the dry matter ingested, 76% was recovered at the duodenum 1 week after weaning, 58% at 2 weeks after weaning and 46% at 8 weeks after weaning. The digestion of acid detergent fibre (ADF) in the stomach was 20% in the first week after weaning and increased to 52% by 8 weeks. The flow of nitrogen to the duodenum was similar to the nitrogen intake. In the first week after weaning, 32% of the nitrogen flowing to the duodenum was of microbial origin; this increased to 74% by 7 weeks after weaning. The flow of essential amino acids to the duodenum as a percentage of intake was greater than that of non-essential amino acids. Also, the apparent digestion of essential amino acids in the intestines was greater than that of non-essential amino acids. By comparing the apparent digestion of amino acids in the hind gut with their requirement for the growth of the calves, it was calculated that methionine would be the first limiting amino acid and threonine the second.
Amino acid content and digestibile energy value of sprouted, rust-affected and sound wheat in pig diets
Authors: Taverner MR , Rayner CJ , Biden RS
Published: November 2004

Sound wheat (FAQ) and wheat damaged by weather (light weight sprouted) and by rust infection (No. 2 and No. 3 off-grade) were analysed for proximate composition and amino acid content. The digestibilities and digestible energy contents of the wheats were determined in studies with eight pigs over four collection periods in two 4 x 4 Latin square designs. Test weights, crude protein contents, glutamic acid contents, digestibilities of dry matter, nitrogen and energy of the damaged wheats were less than those of the sound wheat, but the lysine content of damaged wheat proteins was greater than that in the protein of sound wheat. The digestible energy contents of sound, sprouted and moderately and severely rust-affected wheats were 3982, 3863, 3771 and 3633 kcal kg-1 dry matter, respectively.
Interactions between phyto-oestrogens and steroids in the cervical mucus and uterine weight responses in ewes
Authors: Kelly RW , Allison AJ , Shirley DK
Published: November 2004

Cervical mucus and uterine weight responses were measured in ovariectomized ewes grazing pastures containing isoflavones and coumestans—red clover (Trifolium pyatense) and lucerne (Medicago sativa) respectively. The red clover pastures were highly oestrogenic to the ewes, large productions of mucus and high uterine weights being recorded. Grazing of these pastures for a 12-day period prior to bioassay had no significant effect on either response. The lucerne pastures were only mildly oestrogenic. Administration of progesterone either by subcutaneous implant (375 mg progesterone) or intramuscular injection (10 mg per ewe per day) inhibited the mucus responses to isoflavones but did not decrease the uterine weight responses. In one of two experiments, the uterine weight was unaffected and in the other experiment the weight was enhanced by progesterone treatment. Testosterone propionate injections (10 mg per ewe per day) had no effect on either the cervical mucus or uterine weight responses, but induced oestrus in all ewes.
Effect of stocking rate on fleece measurements and their relationships in merino sheep
Authors: White DH , McConchie BJ
Published: November 2004

The wool characteristics of Merino wethers were measured for 6 years in a stocking rate experiment. The decline in fleece weight due to increasing stocking rate from 4.9 to 12.4 sheep per hectare was usually accompanied by a reduction in fibre diameter and staple length and an increase in staple crimp frequency. The magnitude of these responses differed considerably between years; in one year clean fleece weight was reduced by 50%, with an associated reduction of 5 µm in mean fibre diameter and one of 2 cm in staple length. In four of the six years of the experiment, variation in fibre diameter accounted for at least 50% of the variation in wool production between stocking rate treatments. The relationships between clean fleece weight and fibre diameter were similar between years, mean fibre diameter being reduced by about 1.8 �m for each kilogram reduction in clean fleece weight. Fibre diameter is the major determinant of wool price, and this information should improve the prediction of economic responses to changes in stocking rate.
Effect of water stress on the phasic development of annual Medicago species
Authors: Clarkson NM , Russell JS
Published: November 2004

Although annual medics (Medicago spp.) grow and persist in subtropical eastern Australia, their growth in the field is greatly affected by water stress, which can occur at any time after germination. To study this effect in some detail, the phasic development of six annual Medicago cultivars was measured under four water regimes in a glasshouse. Stress was varied by allowing the soil to dehydrate to different degrees before rewetting, the cycles being repeated continuously. Water stress delayed flowering in all medics except M. scutellata, the mean delay being 14 days. Corresponding delays occurred in the onset of pod production. In contrast the later stages of phasic development were accelerated in some species. Both the length of flowering and life span of the M. truncatula cultivars were significantly reduced by water stress. In the case of cv. Jemalong, severe water stress reduced its length of flowering by 53 days and its life span by 27 days. These results suggest that annual medics have no mechanisms for evading dry seasonal conditions by earlier flowering, but once flowering has begun phasic development is accelerated in some species by water stress. The implications of this study for the interpretation and prediction of field behaviour of annual medics are that water stress can affect phasic development mainly through a delay in flowering. However, the effects appear to be small compared with those due to vernalization, photoperiod and temperature.
Studies of grain production in Sorghum bicolor (L. Moench). VII.* Contribution of plant parts to canopy photosynthesis and grain yield in field stations
Authors: Fischer KS , Wilson GL , Duthie I
Published: November 2004

A method based on 14CO2 uptake and carbon dioxide exchange in sorghum canopies at medium and high density populations allowed the estimation of photosynthesis by plant parts (heads, and leaves at each level of insertion) after anthesis. The relative importance of corresponding parts did not differ between populations, nor did photosynthetic rates per unit leaf area. The latter did decline with successive leaf position down the canopy but were generally compensated by increasing area of these leaves. Averaged over the two populations, which differed little, the heads provided 14% of canopy photosynthesis, and the flag leaf and leaves 2, 3 and 4 were responsible for 21, 24, 21 and 13% respectively. Greater leaf areas per unit land area in the higher population, for each leaf position, resulted in higher total canopy photosynthesis. Previous studies having shown that net photosynthesis after heading corresponds closely to grain yield, the relative importance of plant parts to overall net photosynthesis may be regarded as their relative contribution to grain filling. A direct estimate of their importance in this regard, based on another method, showed the head to contribute 17%, and the next four leaves 17, 25, 20 and 17%. Factors controlling photosynthetic rates of parts are discussed, and the estimates of the importance of photosynthetic sites to grain filling are compared with those reported in previous work.

_____________________
*Part VI, Aust. J. Agric. Res., 27: 35 (1976).
The effect of tree sprays of calcium, boron, zinc and naphthaleneacetic acid, alone and in all combinations, on the incidence of storage disorders in Merton apples
Authors: Martin D , Lewis TL , Cerny J , Ratkowsky DA
Published: November 2004

The effect of four whole-tree sprays at monthly intervals on the fruit mineral element content and on the incidence of storage disorders in Merton apples was investigated for three years. Calcium nitrate, boric acid, zinc nitrate and naphthaleneacetic acid (NAA) were applied singly and in all possible combinations. There were no significant treatment interactions, which implied an absence of synergistic or antagonistic effects between spray components. Calcium nitrate was the only compound whose application consistently reduced the incidence of bitter pit and breakdown following cool storage for 4 months. In one year NAA reduced the incidence of these disorders, but it also reduced mean fruit size and increased the concentration of most of the mineral elements, including calcium, in the fruit at harvest. Zinc nitrate sprays had no effect. Boron application promoted the development of core flush in one year and of breakdown in two years, but did not affect the incidence of bitter pit. No relationship was observed between the levels of calcium and boron in the fruit.
Comparison of lupin varieties for nutritive value as dry standing feed for weaner sheep and for incidence of lupinosis
Authors: Arnold GW , Hill JL , Maller RA , Wallace SR , Carbon BA , Nairn M , Wood PMcR , Weeldenburg J
Published: November 2004

Several lupin varieties were grown on sandy and sandy gravelly soils in a Mediterranean environment. During the three years when they were grown, the rainfall varied from 400 to 700 mm. The yields of dry matter and grain for the cultivars Borre, New Zealand Blue, Uniwhite and Uniharvest of L. angustifolius were not significantly higher than those of the Chapman cultivar of L. cosentinii and the Weiko III cultivar of L. luteus. However, more blocks of these last two cultivars failed owing to weed competition. The nitrogen, phosphorus, sulphur, sodium, neutral detergent fibre and water-soluble carbohydrate contents of the stem, leaf, pod and seed at maturity did not differ greatly between varieties within years. Weaner Merino shcep grazed at 50 sheep ha-1 on these standing dry crops gained up to 10 kg in 80 days. Sheep weight gains over three years were consistently the best for sheep on Borre, Uniwhite and Uniharvest; sheep on Chapman lupins gained little weight in any year, whilst Weiko III gave intermediate gains in one year and poor gains in another. The differences in weight gain were associated in all years with differences in the initial amounts of grain present. Detailed nutritional studies on sheep in the first year showed that the nutritive values of the varieties not causing lupinosis were similar in terms of digestible organic matter intake, volatile fatty acid production and proportions, and blood urea concentration. Abnormal liver metabolism, inferred from the level of ornithine carbamoyl transferase in the blood, occurred in sheep on all varieties during the three years, and lupinosis was confirmed by necropsy in two of the years. Lupinosis resulted in nine deaths out of 250 sheep, but other sheep with liver damage achieved normal liveweight performance. In each year, liver damage occurred on dry lupins before any summer rain. There was a high incidence of lesions of the fungus Phomopsis rossiana on stems of the cultivars Chapman and Weiko III during growth. The presence of lesions at this stage appeared to be more closely associated with the occurrence of lupinosis in summer than with the incidence of Phomopsis infection on dry sterns following summer rains.
Interactions of selenium, cadmium and copper in sheep
Authors: Lee HJ , Jones GB
Published: November 2004

Cadmium supplements (7 5 or 15 mg/day) significantly Increased cadmium concentrations in blood, liver, kidney and muscle in sheep and reduced the concentrations of copper and blood and liver. The small amount of selenium released in the rumen from heavy selenium pellets increased selenium levels in blood, liver, kidney and muscle but did not reduce the concentrations of cadmium In these tissues significantly nor counteract the effect of cadmium on copper storage.
Photosynthetic and storage limitations to yield in Sorghum bicolor (L. Moench)
Authors: Muchow RC , Wilson GL
Published: November 2004

Under favourable growing conditions, the source-sink relationships in grain yield of sorghum were analysed in terms of capacities for net assimilation, of head storage, and of the transport system to move assimilates between source and sink. In four commercial hybrids (Dekalb E57, Pacific Goldfinger, Texas 610SR, and Texas 626) grown at three population densities (20.2, 40.4 and 80.8 plants m-1), the assimilates supply was varied by increasing or decreasing the radiation available per plant (by thinning or shading), the potential gram storage capacity was decreased by spikelet removal, and the transport system was reduced by incision of the culm, all manipulations being performed at anthesis. Decreasing the number of grains increased the size of those remaining in all cultivars at all population densities The degree of Increase was greatest for T626 and T610 and least for E57 Thinning increased the grain size In all cultivars, but only sufficiently to cause a significant increase In gram yield In T610 and T626 Reduction in the assimilate supply by shading decreased the gram size and yield in all cultivars. Reduction In the transport system had no significant effect on gram yield. These results showed that there was surplus capacity for storage and transport In all cultivars In T626, T6L0, and Goldfinger, all post-anthesis assimilate was stored as gram and grams could grow larger The yield was therefore completely source-limited In E57, however, not all port-anthesis assimilate was stored as gram, and these grams showed little capacity to grow larger, which suggests that the yield was partially limited by both source and sink.
Effect of shading at different times on the growth and yield of the potato
Authors: Sale PJM
Published: November 2004

The effect of shading during the periods of new tuber initiation and subsequent bulking were studied with three crops of field-grown potatoes cv Sebago Plots were shaded (34% reduction on full sunlight) up to or after the stage when the young tubers had formed (3 weeks after the onset of initiation), receiving full sunlight for the other half of growth In other treatments plots were shaded throughout growth or not shaded at all In two experiments plots were split for two planting densities (7.14 and 14.28 tubers planted m-2), but density had no effect on the response to shade. Shade during the first part of growth did not affect the numbers of tubers initiation but, compared with unshaded plots, did reduce the numbers which reached a size of 1 cm in diameter or more, which was the same as the final numbers harvested at maturity Shade also delayed by a few days the onset of the rapid tuber-bulking period. Shade during later growth had some additional effect In reducing the maximum bulking rate achieved, so that the final yields from the differentially shaded plots were intermediate between those from the plots either unshaded or shaded throughout Plants receiving late shade had a higher percentage of their total dry weight In the haulm than did unshaded plants.
The effect of the dung beetle, Onthophagus gazella, on the ecology of the infective larvae of gastrointestinal nematodes of cattle
Authors: Bryan RP
Published: November 2004

The ecology of nematode larvae infective for cattle was studied in the vicinity of standardized dung pats experimentally exposed lo the dung beetle, Onthophagus gazella. In moist climatic conditions two, 10 and 30 pairs of O . Gazella reduced the numbers of larvae on grass surrounding dung pats by 40, 74 and 66% respectively, compared with control pats not exposed to beetles. After 84 days, many larvae remained in control pats and pats attacked by two pairs of beetles, but few were found in other pat types. Infective larvae survived for at least 84 days in soil and buried faecal material, and larval migration through soil occurred. The daily temperature variation within dung beetle burrows was considerably less than that of the external environment. This insulation against extremes of temperature probably contributed to the longevity of buried larvae.
Assessment of several pasture species, particularly tropical legumes, for oestrogenic activity
Authors: Little DA
Published: November 2004

Several pasture species, mainly legumes of established or potential application to tropical and subtropical pastoral areas, have been assessed for potential oestrogenic activity. The major criterion of potency adopted was the change in the ratio of the concentration of nucleic acids (RNA/DNA) in the uterine tissue of ovariectomized ewes fed exclusively on the test species for 5 days; in one experiment, samples of uterine tissue were obtained by biopsy before and after the experimental treatment. Increases in uterine weight following five daily injections of 10 µg stilboestrol dipropionate or the ad libitum consumption of fresh red clover (Trifolium pratense) appeared to be comparable at c. 50%; both treatments increased the nucleic acid ratio by more than 100%. It was concluded that change in the nucleic acid ratio offered a much more sensitive technique for the detection of small amounts of oestrogen than the traditional uterine weight method; the response obtamed following the ingestion of red clover, a species known to be oestrogenic, demonstrated the applicability of the nucleic acid ratio technique for the detection of phyto-oestrogenicity. No evidence of oestrogenic activity was obtained from the tropical pasture species Desmodium intorturn, Lotononis bainesii, Macroptilium atropurpureum, Lablab puupureus, Trifolium semipilosum or Digitaria decumbens. The results obtained following the feeding of an experimental strain of creeping-rooted lucerne (Medicago sativa) merely suggested a slight potential for oestrogenicity.