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W. Holtz and D. Smidt

Institut für Tierzucht und Haustiergenetik der Universität Göttingen, 34 Göttingen, Albrecht-Thaer-Weg 1, West-Germany

In all mammals studied so far, with the possible exception of man, it has been shown that sperm cells emerging from the testis have to pass through at least part of the epididymis before they acquire the ability to fertilize (Bedford, Calvin & Cooper, 1973; Bedford, 1974).

The literature regarding the fertilizing capacity of spermatozoa collected from different segments of the epididymis in laboratory animals has been summarized by Paufler & Foote (1968) and Orgebin-Crist (1969). Little information is available for the large domestic species although bulls have been successfully inseminated with spermatozoa from the cauda epididymidis (Lardy & Ghosh, 1952; Barker, 1954; Igboeli & Foote, 1968).

The present experiments were therefore conducted to examine the fertilizing capacity of spermatozoa from different regions of the epididymis in the domestic pig.

Epididymides were obtained by castrating sexually rested

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D. SMIDT, J. STEINBACH and B. SCHEVEN

A convenient source of fertilized ova at the appropriate stage of development is a prerequisite for successful ovum transfer. Since it has not yet been possible to fertilize freshly ovulated, or even follicular oocytes, which have been obtained from slaughter-house material, in vitro, or after transfer to inseminated sows in vivo, the only remaining sources of fertilized eggs are from naturally or artificially inseminated sows during the first days following ovulation. In particular, if the technique of simultaneous, reciprocal egg transfer between individuals is to be employed, it is important to recover the ova from the living animal. Judicious planning of transfer experiments necessitates the recovery of a maximal proportion of the ovulated eggs in a cleaved stage.

Hitherto, only a few experiments on the in-vivo recovery of swine ova have been described. Schmidt &

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F. ELLENDORFF, E. ROTH and D. SMIDT

Sexual maturity can be advanced in the sow by hormonal treatment (Schahidi, 1968; Majerciak, Smidt, Schahidi & Harms, 1969) but has not been tried successfully in the boar.

Ten boars were investigated under the normal conditions of the experimental station (Roth, 1969). Table 1 shows the age and treatment schedule. The following substances were used: fsh(nih-fsh-p1), lh(nih-lh-b6), and Testoviron (Testoviron®—Depot, Schering AG Berlin). Biopsies were taken at the intervals shown in Table 1. Castration was performed on the 53rd day of the experiment.

The following aspects of sexual behaviour were studied: sexual excitement, indicated by aggressiveness towards other boars, frothing from the mouth, and interest in sows in oestrus, as shown by mounting and erection of the penis with and without protrusion from the prepuce. In order to evaluate gonadal

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F. ELLENDORFF, H. F. RÖVER and D. SMIDT

Summary.

The effect of cyproterone acetate on the duration of pregnancy and the number of embryos (normal, hypertrophied or degenerated) was investigated. Pregnant NMRI-strain albino mice were injected on Days 1 to 10, or Days 10 to 15 with either 0·5 or 5·0 mg cyproterone acetate (CA) or the vehicle (V). In the CA-treated animals, no parturitions occurred up to Day 21 of pregnancy. The number of offspring did, in general, not differ between the CA-treated animals and the controls. The number of normal offspring was less and the number of abnormal embryos was larger in the CA-treated animals compared with the controls. Hormonal induction of parturition showed positive results after oestrogen—oxytocin administration. The effect of CA was attributed (a) to its progestational activities, and (b) to possible direct effects on the development of the embryos.

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F. Ellendorff, M. Forsling, N. Parvizi, H. Williams, M. Taverne and D. Smidt

Summary. A single i.m. injection of 5 mg PGF-2α evoked a significant elevation of plasma oxytocin values in sows 6 days post partum and during dioestrus. Plasma vasopressin levels in dioestrous sows were not significantly affected by PGF-2α. It is concluded that circulating steroid levels do not interfere with the response of oxytocin levels to PGF-2α.