摘要:

Contents:Insemination results per bull and district of AI (or technician) were analysed in a 5 year study. Return Rates (RR) were registered between Oct. 1976 and Sept. 1981. Data included 856 850 first AI made by 56 technicians. Depending on years, AI were made with the semen of 81 to 103 bulls of 5 breeds. Only bulls which performed at least 500 AI's per year were taken into account. A first analysis made with the data of 14 bulls represented during the 5 years show that: 1) the breed, the bull within breed and district of AI (or technician) were the most important factors influencing RR. RR were less affected by other factors such as the size of the herd or the year. 2) results given for successive RR were nearly identical from RR24to RR90. 3) the effect of breed, bull and district of AI were less important on the variable illustrating more specificially late return in oestrus (RR25–300). Yearly analysis involving larger number of bulls gave very similar results to the 5 year study. Variability due to the district of AI (or technician) and to the bull were of the same magnitude. Maximum differences between bulls or districts varied from 10% (RR24) to 20% (RR90). As strong relationships between bull and district of AI or technician were found, complementary analyses from the 1978 set of data were made to investigate how the variability due to the district of AI could introduce bias when estimating bull's RR. Comparisons between models were made on the basis of correlations between a reference model including a district effect and reduced models. For RR24and RR90correlations between solutions were always higher than 0.97. This show that if sufficient number of AI's per bull are performed no major bias is introduced and the district of AI or technician is neglectable when evaluating bull's R

ISSN:0936-6768    

DOI:10.1111/j.1439-0531.1991.tb01533.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

Inhalt:Am Rinderschlag Deutsche Schwarzbunte wurden die Phänotypen verschiede‐ner Zwillingsformen verglichen: (1) monozygote Zwillinge nach mikrochirurgischer Teilung der Blastozysten und Transfer in zwei verschiedene Empfängermütter (allo‐uterine, monozygote Zwillinge); (2) monozygote Zwillinge in einer Empfängermutter durch spontane Teilung nach Embryotransfer entstanden (isouterine, monozygote Zwillinge); (3) natürliche Geschwister, die nach Embryotransfer in unterschiedlichen Empfängermüttern aufwachsen und damit wie allouterine, dizygote Zwillinge gehand‐habt werden können.An 105 derartigen Kälbern im Alter von 3 Wochen bis zu mehr als einem Jahr wurden wiederholt 12 verschiedene Körperlängen– und Körperbreitenmaβe und das Köorperge‐wicht bestimmt. Mittels Varianzanalyse Typ II nach Eisenhart wurden die Komponen‐ten s2withinfür die allouterinen und für die isouterinen Zwillingspärchen und für die Vollgeschwistergruppen errechnet und verglichen.Sie betragen in % der gesamten phänotypischen Varianz (und zeigen damit die Gröbte des Einflusses folgender Umwelten auf diese an): Bei monozygoten, allouterinen Zwil‐lingen 5–25% (prä–+ postnatale Umwelteinflüsse), bei monozygoten, isouterinen Zwil‐lingen meist<7% (vornehmich postnatale Umwelteinflüsse). Der uterine Einfluβ der Empfängermutter auf die postpartale Entwicklung transferierter Embryonen bis zu einem Jahr beträgt etwa 4–20% der gesam ten phänoty pischen Varianz eines Merkmales. Die additive genetische Varianzkomponente der genannten Merkmale wurde bestimmt aus dem Vollgeschwistervergleich. Sie beträgt 3366% der Gesamtvarianz. Die Sum‐me aller hier direkt bestimmten Varianzkomponentenerklärt nur 5070% der phäno‐typischen Gesamtvarianz. Der verbleibende Rest wird als dritte Varianzkomponente (“Emergenesis”, Intagible Variance) angesprochen.Bei isouterin ausgetragenen Bullenzwillingen bedingt die Zwillingsschwangerschaft prä‐natal verursachte Differenzen, die extrem groβ und noch nach einem Jahr nachweisbar sind. Sie mahnen zur V

ISSN:0936-6768    

DOI:10.1111/j.1439-0531.1991.tb01534.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

Contents:Placentomes were romoved from 4 to 6 cows before/after treatment with dexamethasone (DXMS) at days 200/205, 220/225, and 250/255 of pregnancy. Preparations of cotyledonary tissue were first perfused with plain HEPES buffered medium 199 (rinsing fraction), followed by the addition of either 3H‐androstenedione and 3H‐pregnenolone or unlabelled cholesterol and pregnenolone as substrates. As indicated by examining the rinsing fractions from untreted animals estrone concentrations. (output) increased from day 200 to day 250 of pregnancy, treatment with DXMS led to a further significant increase on all days examined. Concomitantly with this increase a decrease in pregnenolone and progesterone was observed. Distinct effects of substrate additon were limited to the transformation of 3H‐pregnenolone into 3H‐testosterone/epitestosterone (yield ˜ 8%), furtheron the addition of unlabelled pregnenolone (but not of cholesterol), significantly increased progesterone synthesis as determined by radio immunoassay. Neither these nor other results published till now account for the high estrogen production by the bovine placenta on in vivo conditions. It is concluded that the in vitro systems used so far not or only in part reflect the in vivo conditions necessary to allow complete expression of the steroidogenic capacity of the bovine tro

ISSN:0936-6768    

DOI:10.1111/j.1439-0531.1991.tb01535.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

Contents:An experiment was conducted to characterize the ovarian follicles as well as follicular oocytes in heifers following the treatment with a dose of 2500 I.U. or 7500 I.U. of PMSG. Ovaries were collected from heifers slaughtered 72 or 96 h after PMSG injection. The control group consisted of non stimulated heifers. The mean numbers of follicles ≥ 6 mm in diameter were 9.1 ± 7.0 and 16.8 ± 11.2 for ovaries collected 72 h after PMSG injection (group I and II), and 18.5 ± 10.0 and 28.1 ± 20.8 for ovaries collected 24 h later (group III and IV). The mean number of morphologically normal oocytes was 1.2; 1.6; 0.8 and 2.1 for the experimental groups'I to IV. The dose of PMSG did not affect the morphology of the oocytes but it influenced the me

ISSN:0936-6768    

DOI:10.1111/j.1439-0531.1991.tb01536.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

ISSN:0936-6768    

DOI:10.1111/j.1439-0531.1991.tb01537.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

ISSN:0936-6768    

DOI:10.1111/j.1439-0531.1991.tb01538.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

ISSN:0936-6768    

DOI:10.1111/j.1439-0531.1991.tb01539.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

ISSN:0936-6768    

DOI:10.1111/j.1439-0531.1991.tb01540.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

ISSN:0936-6768    

DOI:10.1111/j.1439-0531.1991.tb01541.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY