Australian journal of biological sciences最新文献

{"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":null,"pages":null},"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}

{"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":null,"pages":null},"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":"Potential for fecundin to influence the reproductive performance of merino ewes in Western Australia.","authors":"K P Croker,&nbsp;R I Cox,&nbsp;M A Johns,&nbsp;T J Johnson,&nbsp;D Roberts,&nbsp;M Salerian,&nbsp;F Sunderman","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>Four experiments were conducted at different locations in Western Australia to evaluate the effectiveness of immunizing young (maiden, 1 1/2 year old) and adult Merino ewes with Fecundin to improve their reproductive performances. The ovulation rates of immunized maiden ewes was increased (0.06-0.30) above that of untreated ewes in both experiments 1 and 2. However, there were no significant improvements in the marking percentages for the immunized ewes with the differences between the untreated and immunized ewes ranging from -16.4 to 5.8%. In comparison with untreated ewes immunization 6 and 2 weeks before the start of joining depressed ewe fertility by 26.1% whereas immunization 8 and 4 weeks before the start of joining did not significantly affect fertility. The availability of oat grain ad libitum prior to parturition and during early lactation did not improve the survival of lambs born to immunized ewes. In experiments 3 and 4 immunization of adult Merino ewes increased their ovulation rates (0.41-0.63) above untreated controls and tended to increase the proportion of pregnant ewes which had multiple pregnancies (from -2.3 to 34.2%). The responses at the end of lambing were variable (from -19.8 to 37.5% lambs marked) with high lamb mortalities occurring in some experiments. There was no adverse effect on the reproductive performances following consecutive annual immunizations over 3 years and the absence of treatment for 1 year did not prevent a response in the following year.</p>","PeriodicalId":8573,"journal":{"name":"Australian journal of biological sciences","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1988-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"14397531","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":"Potential for fecundin to influence the reproductive performance of merino ewes in Western Australia.","authors":"K. Croker, R. Cox, M. Johns, T. Johnson, D. Roberts, M. Salerian, F. Sunderman","doi":"10.1071/BI9880047","DOIUrl":"https://doi.org/10.1071/BI9880047","url":null,"abstract":"Four experiments were conducted at different locations in Western Australia to evaluate the effectiveness of immunizing young (maiden, 1 1/2 year old) and adult Merino ewes with Fecundin to improve their reproductive performances. The ovulation rates of immunized maiden ewes was increased (0.06-0.30) above that of untreated ewes in both experiments 1 and 2. However, there were no significant improvements in the marking percentages for the immunized ewes with the differences between the untreated and immunized ewes ranging from -16.4 to 5.8%. In comparison with untreated ewes immunization 6 and 2 weeks before the start of joining depressed ewe fertility by 26.1% whereas immunization 8 and 4 weeks before the start of joining did not significantly affect fertility. The availability of oat grain ad libitum prior to parturition and during early lactation did not improve the survival of lambs born to immunized ewes. In experiments 3 and 4 immunization of adult Merino ewes increased their ovulation rates (0.41-0.63) above untreated controls and tended to increase the proportion of pregnant ewes which had multiple pregnancies (from -2.3 to 34.2%). The responses at the end of lambing were variable (from -19.8 to 37.5% lambs marked) with high lamb mortalities occurring in some experiments. There was no adverse effect on the reproductive performances following consecutive annual immunizations over 3 years and the absence of treatment for 1 year did not prevent a response in the following year.","PeriodicalId":8573,"journal":{"name":"Australian journal of biological sciences","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1988-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77234322","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, K. Heasman, J. Nemorin, T. J. Robinson","doi":"10.1071/BI9880057","DOIUrl":"https://doi.org/10.1071/BI9880057","url":null,"abstract":"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.","PeriodicalId":8573,"journal":{"name":"Australian journal of biological sciences","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1988-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84049674","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":"Current topics in artificial insemination of sheep.","authors":"G. Evans","doi":"10.1071/BI9880103","DOIUrl":"https://doi.org/10.1071/BI9880103","url":null,"abstract":"There have been developments in several aspects of artificial insemination (AI) in recent years, some of which have been directly responsible for proliferation of AI in the sheep-breeding industries of several countries. The most notable advances have probably been associated with the development of intrauterine insemination by laparoscopy. There is potential for refinement of some of the related techniques, particularly in the area of control of ovulation and definition of appropriate times and optimum doses of spermatozoa for insemination. It is unlikely that laparoscopic AI will be developed sufficiently that it will become readily affordable, and therefore widely practised, by commercial producers. Unfortunately, there has been little progress in the past few years in improvement of the methods of cryopreservation of ram semen. There is considerable potential for AI to have a significant impact on the genetic improvement of sheep, though this has yet to be evaluated in practice. However, if the full potential of AI in sheep is to be realized, it will likely only happen when methods of freezing semen are improved sufficiently that cervical or even vaginal insemination can be widely used with frozen-thawed semen, or when practicable methods of deep cervical or intrauterine insemination through the cervix are developed.","PeriodicalId":8573,"journal":{"name":"Australian journal of biological sciences","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1988-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78147291","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":"Release of Cuticle from Wool by Agitation in Solutions of Detergents","authors":"K. Ley, W. Crewther, G. Flanagan, L. N. Jones, R. Marshall","doi":"10.1071/BI9880163","DOIUrl":"https://doi.org/10.1071/BI9880163","url":null,"abstract":"Scanning and transmission electron microscopy were used to study the progressive disruption of Merino wool during the vigorous agitation of the fibres in aqueous 10J0 (w Iv) solutions of sodium dodecylsulfate (SDS). In contrast to the general disruption observed when wool was vigorously agitated in formic acid, the cuticle was slowly stripped from the fibre with virtually no release of cortical material unless prolonged periods of agitation were used. A similar type of disruption took place in aqueous 10J0 (w Iv) solutions of cetyltrimethylammonium bromide (CETAB) and Triton X-lOO. After the agitation in 10J0 (w/v) SDS solution, the released cuticle fragments and the remaining fibres were examined. Only a minority of the cell portions constituting the cuticle fragments had been cleaved within the endocuticle. Often, the fragments included portions from more than one cuticle cell, with the cell junctions still intact. An understanding of the disruptive process was facilitated by the frequent observation, on residual fibres, of low ridges on exposed underlying cuticle cells. These low ridges corresponded with the distal edges of the originally overlying cuticle cells. Amino-acid analysis and scanning electron microscopy performed on preparations of cuticle obtained in solutions of the above detergents and in formic acid indicated close similarities between all of the cuticle preparations.","PeriodicalId":8573,"journal":{"name":"Australian journal of biological sciences","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1988-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84727383","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":"Nitrogenase activity in the queensland fruit fly, dacus tryoni","authors":"K. Murphy, Ic Mac Rae, D. Teakle","doi":"10.1071/BI9880447","DOIUrl":"https://doi.org/10.1071/BI9880447","url":null,"abstract":"When 5-day-old laboratory-raised Queensland fruit flies (Dacus tryoni) were fed a dinitrogen-fixing bacterial strain of Klebsiella oxytoca isolated from the crop of a wild fly, acetylene reduction (nitrogenase) activity associated with the flies was detected after 2 to 3 days and persisted for at least 22 days. Flies not fed the dinitrogen-fixing strain were negative for acetylene reduction until 21 days after emergence. Presumably such dinitrogen-fixing bacteria are able to supply some Queensland fruit flies with a small part of their nitrogen requirements, but its importance is unknown.","PeriodicalId":8573,"journal":{"name":"Australian journal of biological sciences","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1988-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89667485","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":"Development of a radioimmunoassay for plasma C-peptide in sheep: kinetics of C-peptide and effects of exogenous growth hormone and glucose on insulin and C-peptide.","authors":"D Leenanuruksa,&nbsp;G H McDowell","doi":"10.1071/bi9880517","DOIUrl":"https://doi.org/10.1071/bi9880517","url":null,"abstract":"<p><p>An antiserum to purified bovine C-peptide was used to develop a sensitive radioimmunoassay for C-peptide in sheep. The assay was used to measure kinetics of C-peptide and insulin in non-pregnant and non-lactating sheep. Injected, purified C-peptide was distributed in pools comprising c. 11.4% of liveweight, the half time of C-peptide was estimated as 13.7 min and its clearance rate was c. 5 ml kg-1 min-1. In lactating ewes exogenous recombinant bovine growth hormone (rebGH) increased both plasma insulin and C-peptide as did glucose challenge given before and during administration of rebGH. Estimates of insulin secretion rate in lactating ewes were c. 7 x 10(-3) and 8.5 x 10(-3) nmol kg-1 min-1 before and after glucose challenge prior to injections of rebGH. After 4 days of injection of rebGH, corresponding values were c. 8 x 10(-3) and 10 x 10(-3) nmol min-1 kg-1.</p>","PeriodicalId":8573,"journal":{"name":"Australian journal of biological sciences","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1988-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"14209988","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":"Group-specific and type-specific gel diffusion precipitin tests for bluetongue virus serotype 20 and related viruses.","authors":"J M Sharp,&nbsp;I R Littlejohns,&nbsp;T D St George","doi":"10.1071/bi9880553","DOIUrl":"https://doi.org/10.1071/bi9880553","url":null,"abstract":"<p><p>Using antigens prepared from cell cultures infected by bluetongue (BLU) virus type 20 (BLU-20), and sera from cattle which had recovered from experimental infection by that virus, two distinct precipitin reactions were demonstrated by immunodiffusion. Two distinct gel diffusion precipitin tests were developed based on these reactions. The antigen of one was common to BLU-20 and two other Australian BLU isolates, CSIRO 154 (BLU-21) and CSIRO 156 (BLU-1). It was therefore concluded to be a group-specific test. The antigen of the second appeared to be unique to BLU-20. The test based on this antigen correlated well with the virus neutralization test for BLU-20 and it was therefore concluded to be type-specific. Similar methods applied to a virus of the Palyam (PAL) group demonstrated two precipitin reactions of similar broad (group) and narrow (type) specificity.</p>","PeriodicalId":8573,"journal":{"name":"Australian journal of biological sciences","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1988-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"13994344","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}