Australian journal of biological sciences最新文献

{"title":"Sheep Reproduction Modelled as a Markov Series. I. The Model","authors":"M. Carrick","doi":"10.1071/BI9880133","DOIUrl":"https://doi.org/10.1071/BI9880133","url":null,"abstract":"Sheep reproduction from ovulation to weaning was modelled as a Markov series of multiple binomial distributions, which required a minimum of assumptions and a small number of parameters for the entire reproductive process. Methods of constructing the model and of estimating the parameters are described, and results from simulated example flocks with different ovulatory potentials are presented. A variety of potential applications, for example as an adjunct to economic modelling and methods of validation and use in the analysis of reproductive experiments, are discussed.","PeriodicalId":8573,"journal":{"name":"Australian journal of biological sciences","volume":"5 1","pages":"133-146"},"PeriodicalIF":0.0,"publicationDate":"1988-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75147168","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Effect of vitamin C administration on serum and egg-yolk cholesterol level of the chicken.","authors":"A S al-Janabi,&nbsp;S R al-Kattib,&nbsp;Z D Taha","doi":"10.1071/bi9880403","DOIUrl":"https://doi.org/10.1071/bi9880403","url":null,"abstract":"<p><p>Ascorbic acid (vitamin C) was given to 144-days-old layer chickens mixed with their ration at three concentrations: 30, 60 and 90 p.p.m. for 6 months. Cholesterol levels in blood serum (CS) and egg yolk (CE) were measured every 6 weeks (four periods); there was a marked decrease in CS in most treated birds, especially those receiving the highest concentration of vitamin C. There was also a slight decrease in CE in most treated birds. Thyroidal weight showed a significant increase in most treated groups, especially those receiving the highest concentration of vitamin C.</p>","PeriodicalId":8573,"journal":{"name":"Australian journal of biological sciences","volume":"41 4","pages":"403-7"},"PeriodicalIF":0.0,"publicationDate":"1988-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"14400554","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Milk composition in the northern brown bandicoot, Isoodon macrourus (Peramelidae, Marsupialia).","authors":"J C Merchant,&nbsp;J A Libke","doi":"10.1071/bi9880495","DOIUrl":"https://doi.org/10.1071/bi9880495","url":null,"abstract":"<p><p>Milk samples were obtained at regular intervals throughout lactation from northern brown bandicoots, Isoodon macrourus, in captivity. Total concentration of milk solids was initially 7% (w/w) and increased linearly to 45% (w/w) by 55 days. Carbohydrate, lipid and protein concentrations increased from about 2% (w/w) to about 7-8% (w/w) at 30 days. Thereafter they diverged, with lipid increasing to between 25-30% (w/w) at 56 days, protein reaching maximal values of 10-15% (w/w) at just over 40 days and carbohydrate gradually declining to about 5% (w/w) at 56 days before a rapid fall to 1-2% (w/w) at the completion of lactation. The milk of the bandicoot exhibits a similar pattern of change during the course of lactation to that shown by other marsupials.</p>","PeriodicalId":8573,"journal":{"name":"Australian journal of biological sciences","volume":"41 4","pages":"495-505"},"PeriodicalIF":0.0,"publicationDate":"1988-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"14400557","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Short-term effects of exogenous growth hormone: effects on milk production and utilization of nutrients in muscle and mammary tissues of lactating ewes.","authors":"G H McDowell,&nbsp;D Leenanuruksa,&nbsp;P Niumsup,&nbsp;J M Gooden,&nbsp;J G van der Walt,&nbsp;R Smithard","doi":"10.1071/bi9880279","DOIUrl":"https://doi.org/10.1071/bi9880279","url":null,"abstract":"<p><p>Exogenous bovine growth hormone at a dose of 0.1 mg kg-1 liveweight increased yields of milk and milk constituents and milk fat content when injected over 5 days into ewes in mid-lactation. These changes in milk production were associated with changes in the supply to, and utilization of, nutrients by leg muscle and mammary tissues. Arterial concentrations of glucose and non-esterified fatty acids increased significantly, concentrations of lactate and 3-hydroxybutyrate tended to increase, and concentrations of triglycerides associated with very low-density lipoproteins decreased significantly. Growth hormone increased mammary uptake of non-esterified fatty acids, decreased mammary uptake of very low-density lipoproteins and tended to reduce the release of lactate from leg muscle. Oxidation of non-esterified fatty acids in the whole body and mammary tissue was increased by growth hormone and there was a tendency for reduction of glucose oxidation in mammary tissues. During injection of growth hormone, blood flow to leg muscle and mammary tissues increased as did the calculated ratio of blood flow; milk yield. These changes in blood flow, together with changes in arterial concentrations and tissue utilizations of key metabolites, were sufficient to account for the synthesis of extra milk and milk constituents.</p>","PeriodicalId":8573,"journal":{"name":"Australian journal of biological sciences","volume":"41 3","pages":"279-88"},"PeriodicalIF":0.0,"publicationDate":"1988-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"14396197","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Complete nucleotide sequence of the bovine beta-casein gene.","authors":"J Bonsing,&nbsp;J M Ring,&nbsp;A F Stewart,&nbsp;A G Mackinlay","doi":"10.1071/bi9880527","DOIUrl":"https://doi.org/10.1071/bi9880527","url":null,"abstract":"<p><p>The beta-casein gene is a member of a small gene family encoding the calcium-sensitive caseins, which are specifically synthesized and secreted by the mammary gland during lactation in response to both peptide and steroid hormones. The caseins are involved in the transport of calcium phosphate in milk, which is important for bone development in the infant mammal. We report here the organization and complete DNA sequence of the 8.5 kb long bovine beta-casein gene. Comparison with the rat beta-casein gene reveals that the exons of both genes correspond exactly. The 5' flanking sequences of all Ca-sensitive casein genes are conserved within the proximal 200 bp and contain several elements that probably function as cis-acting regulatory elements, including an octamer-like motif, and SV40-type core enhancer and a sequence that appears to be common to all lactoprotein genes. The latter sequence is flanked on either side by 12 bp direct repeats. These direct repeats are themselves each part of sequences that display two-fold symmetry. The first 30 nucleotides of the 3' flanking regions in the bovine and rat beta-caseins are well conserved, indicating that they are likely to be involved in the mechanism of 3' end processing of the primary transcript.</p>","PeriodicalId":8573,"journal":{"name":"Australian journal of biological sciences","volume":"41 4","pages":"527-37"},"PeriodicalIF":0.0,"publicationDate":"1988-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1071/bi9880527","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"14398837","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Characterization of proteolytic and collagenolytic enzymes from the larvae of Lucilia cuprina, the sheep blowfly.","authors":"V M Bowles,&nbsp;P R Carnegie,&nbsp;R M Sandeman","doi":"10.1071/bi9880269","DOIUrl":"https://doi.org/10.1071/bi9880269","url":null,"abstract":"<p><p>Isoelectric focusing was used to characterize proteolytic enzymes in homogenate and excretory-secretory preparations of the larvae of L. cuprina, the sheep blowfly. Zymogram overlays showed that the larvae produce a number of highly active proteases which have a wide range of isoelectric points and molecular weights. The alkaline and neutral pI proteases were inhibited by phenylmethyl-sulfonylfluoride, leupeptin and aprotinin; this indicated the presence of serine in the active site. Pepstatin and the metal chelating agent ethylenediaminetetraacetic acid had no effect on the activity of any of the proteases. Optimal pH for activity of the proteases was between 7 and 8. In addition, the proteases were found to be heat labile. Digestion of collagen fibrils confirmed the existence of collagenolytic activity in the excretory-secretory enzyme preparations. It is suggested that these enzymes may be involved in the nutrition of the larvae and in the pathogenesis of the lesion on the skin.</p>","PeriodicalId":8573,"journal":{"name":"Australian journal of biological sciences","volume":"41 2","pages":"269-78"},"PeriodicalIF":0.0,"publicationDate":"1988-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1071/bi9880269","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"13627324","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Effect of myiasis and acute restraint stress on plasma levels of immunoreactive beta-endorphin, adrenocorticotrophin (ACTH) and cortisol in the sheep.","authors":"D A Shutt,&nbsp;A I Smith,&nbsp;C A Wallace,&nbsp;R Connell,&nbsp;L R Fell","doi":"10.1071/bi9880297","DOIUrl":"https://doi.org/10.1071/bi9880297","url":null,"abstract":"<p><p>Cutaneous myiasis in sheep arising from the activity of Lucilia cuprina larvae can result in significant physiological changes in susceptible animals. The stress imposed on the pituitary-adrenal axis of the sheep in response to myiasis and acute restraint is the subject of this investigation. Merino wethers were exposed to handling restraint, and blood sampling, during examination for blowfly strike; where necessary, they were treated for cutaneous myiasis. Significant changes in the plasma concentrations of immunoreactive beta-endorphin (beta-EP), ACTH and cortisol were found in sheep with extensive myiasis, as compared with unstruck sheep or those with only localized myiasis. In five susceptible sheep with extensive cutaneous myiasis, mean plasma levels of beta-EP, ACTH and cortisol were 307 +/- 71 pg ml-1, 953 +/- 58 pg ml-1 and 232 +/- 46 nmol l-1 respectively, compared with 818 +/- 89 pg ml-1, 641 +/- 41 pg ml-1 and 107 +/- 17 nmol l-1 in six unstruck sheep handled similarly. Whereas significant increases in plasma ACTH and cortisol can result from pituitary-adrenal responses to acute emotional or surgical stress, and are usually accompanied by a concomitant release of beta-EP from the pituitary, the present findings indicate a marked reduction in beta-EP levels and a significant increase in ACTH and cortisol in sheep following blowfly strike and acute handling restraint. This result suggests that cutaneous myiasis in susceptible sheep can alter the pituitary-adrenal response to acute restraint stress, and this could occur either by an alteration of precursor processing in the pituitary or by the selective release of ACTH.</p>","PeriodicalId":8573,"journal":{"name":"Australian journal of biological sciences","volume":"41 3","pages":"297-301"},"PeriodicalIF":0.0,"publicationDate":"1988-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1071/bi9880297","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"13993127","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A radioimmunoassay for fluorogestone acetate (FGA) and its application to the measurement of plasma FGA and progesterone in ewes treated with FGA-impregnated intravaginal sponges.","authors":"O Gaston-Parry,&nbsp;K Heasman,&nbsp;J K Nemorin,&nbsp;T J Robinson","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>Simultaneous concentrations of endogenous progesterone and exogenous FGA have been measured in ewes treated with FGA-impregnated intravaginal sponges at several times relative to the expected time of release of LH. First, a direct double antibody radioimmunoassay (RIA) for FGA, with good precision, sensitivity and reproducibility, was developed and validated. An oxime derivative was prepared and then conjugated to human serum albumen at the 3-position to produce the antigen. Antibodies raised in New Zealand White rabbits showed little cross-reactivity with related steroids. FGA was estimated in extracted and unextracted plasma; results were indistinguishable. Second, sponges impregnated with 40 mg FGA were inserted into 20 anoestrous crossbred ewes for 12 days; 500 i.u. pregnant mare serum gonadotrophin (PMSG) was injected at withdrawal. Similar sponges were reintroduced into four ewes at each of the intervals 1, 3, 5, and 7 days later; three ewes served as controls. Plasma concentrations of progesterone and FGA were estimated by RIA daily during treatment and at intervals of 2 h for 12 h and at 18 and 24 h after withdrawal. The plasma profiles of FGA during the two successive periods of insertion were remarkably similar. A concentration of 3.0 ng/ml (s.e.m. +/- 0.22) was attained on day 1, falling to 1.5 ng/ml (+/- 0.15) by day 4. Thereafter, the concentration was maintained at 1.1 ng/ml (+/- 0.08). Plasma progesterone concentrations were at basal levels of less than 0.2 ng/ml during the first (acyclic) period of sponge insertion. During the second (cyclic) period there was a marked difference related to the time of sponge insertion. Insertion on day 1 (before LH release) resulted in complete inhibition of luteal activity; insertion on day 3, 5 or 7 was followed by apparently normal luteal function. There was no evidence of any feedback mechanism of exogenous progestagen on endogenous progesterone and no interaction. It is concluded that a 12-day treatment is needed in cyclic ewes for full synchronization and that sponges impregnated with 40 mg FGA will maintain an effective plasma concentration of greater than 1 ng/ml to the end of this period.</p>","PeriodicalId":8573,"journal":{"name":"Australian journal of biological sciences","volume":"41 1","pages":"57-67"},"PeriodicalIF":0.0,"publicationDate":"1988-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"13627020","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The proposed use of melatonin in controlled sheep breeding.","authors":"A L Poulton","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>The regulation by melatonin of hypothalamic-pituitary events in the ewe to advance seasonal oestrous activity, with no undesirable effects upon fertility, and its induction of those seasonal responses associated with short days indicates an essential role for melatonin in controlled-breeding programs in major sheep-producing countries. The development of suitable controlled-release systems to provide a choice of practical methods of melatonin delivery under field conditions is discussed as also are geographical and breed factors in controlled breeding with melatonin.</p>","PeriodicalId":8573,"journal":{"name":"Australian journal of biological sciences","volume":"41 1","pages":"87-96"},"PeriodicalIF":0.0,"publicationDate":"1988-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"14210612","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Controlled sheep breeding: update 1980-1985.","authors":"T J Robinson","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>This contribution to the Symposium concerns four topics which have been addressed in our laboratory over the past five years. First, the responses to a controlled light environment of Merino ewes and rams have been compared with those of two British breeds. The endocrinological patterns were similar in all breeds but cyclic ovarian activity and ram libido were different. While showing a degree of entrainment to photoperiod, the breeding patterns were much less rigidly controlled in the Merinos than in the others. Second, the effectiveness of establishment of a cervical reservoir of spermatozoa, in ewes in which oestrus and ovulation have been controlled, has been re-examined. This is highly dependent on the time of insemination relative to that of the release of LH. Maximum numbers are found when ewes are inseminated shortly after the LH peak, i.e. some 6-10 h after the onset of oestrus. Third, the quantitative and temporal endocrinological and behavioural events following standard, progestagen-PMSG treatment have been quantified. Contrary to earlier expressed beliefs, these events are remarkably predictable provided an intensive system of mating or detection of oestrus is used. The onset of oestrus in treated anoestrous crossbred ewes has a normal distribution, with a range of 24 h, centred around a mean of 33 h after withdrawal of a 30 mg Cronolone intravaginal sponge and injection of 500 i.u. PMSG. This period of time is dose-dependent. The LH peak occurs 4.5 +/- 0.7 h later and the times of onset of oestrus and of LH release are highly correlated (r = 0.93). Ovulation is some 24 h later again. Fourth, differences in the response of ewes to different batches of PMSG have been defined. While the three commercial preparations studied regularly induced ovulation in anoestrous ewes at doses of 250 i.u. and above, the quantitative responses varied greatly. One preparation would not induce multiple ovulation, even at high doses. There are differences in steroidogenesis and in pregnancy rates, associated with dose of PMSG and the consequent ovulation rate: the ideal would be for every ewe to shed two or three ova. A higher ovulation rate is acceptable, as early embryonic mortality generally reduces the litter size. This is particularly important in deep anoestrus. However, this does not solve the problem of breeding in early lactation.</p>","PeriodicalId":8573,"journal":{"name":"Australian journal of biological sciences","volume":"41 1","pages":"1-13"},"PeriodicalIF":0.0,"publicationDate":"1988-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"14209413","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}