Reproduction

LIGHTFOOT, R. J.; SALAMON, S.

doi: 10.1530/jrf.0.0220385pmid: 5453373

Summary.The transport of fresh and frozen spermatozoa through the genital tract of the ewe was studied in four experiments.Extremely low numbers of spermatozoa were recovered from the Fallopian tubes of ewes after insemination with either fresh (diluted) or frozen spermatozoa when both were used at a concentration of 0·4 ×109 motile spermatozoa/ml, but the fertilization rate was higher with the fresh semen. High doses of oxytocin did not affect sperm transport, but significantly depressed the fertilization rate. Concentrating the thawed semen before insemination resulted in increased numbers of spermatozoa recovered from the Fallopian tubes. Fresh semen resulted in even higher numbers in the tubes and an increased proportion of ova recovered with spermatozoa on the zona pellucida. Ewes were slaughtered 30 min after insemination with either fresh or frozen semen of varying concentration. The number of spermatozoa recovered from the cervix after insemination with frozen semen was dependent upon the concentration of motile spermatozoa in the inseminate. At equal concentration, fresh semen was superior to frozen semen. Uterine insemination at varying periods before ovulation showed that a proportion of the pellet-frozen spermatozoa survived in the genital tract with retention of fertilizing ability for 18 to 35 hr.

LIGHTFOOT, R. J.; SALAMON, S.

doi: 10.1530/jrf.0.0220399pmid: 5465733

Summary.A factorial experiment was conducted to examine the effects in Merino ewes of method of insemination and semen type on embryonic loss (fertilization rate versus lambing rate).The results showed that:frozen semen (pellet method) was of lower fertility than fresh semen (49% versus 70% respectively). there was little embryonic mortality following either the cervical or cervical traction methods of insemination (13% and 6% respectively), but substantial loss occurred following uterine insemination (47%). Results for both fresh and frozen semen were similar in this respect.Normal cervical insemination (two inseminations at a 12-hr interval within one oestrus) with frozen semen of high concentration (1·6 × 109 motile spermatozoa/ml, 0·1 ml dose) resulted in ewe fertilization and lambing rates of 58% and 50%, respectively.

SALAMON, S.; LIGHTFOOT, R. J.

doi: 10.1530/jrf.0.0220409pmid: 5465734

Summary.A series of five experiments was conducted to examine ewe fertility following insemination with ram spermatozoa frozen by the pellet method.With thawed semen of low concentration and relatively poor quality, fertility was very poor with an overall non-return rate of 5·6% (269 ewes). Following insemination with thawed semen of low and high sperm concentration (0·5 versus 1·5×109 motile cells/ml) the proportions of ewes lambing were 23·7 and 43·8% respectively. There was no difference in the proportion of ewes lambing when the inseminate volume was reduced from 0·3 to 0·1 ml (Exp. 2, dilute semen) or from 0·15 to 0·05 ml (Exp. 3, concentrated semen). Two inseminations gave higher fertility than a single insemination (Exp. 2, 38·8% versus 22·6%; Exp. 3, 53·0% versus 39·7%) but the magnitude of the response varied according to both the time of insemination and the concentration and volume of the inseminate.High doses of oxytocin (5 or 10 i.u., i.m.) depressed the proportion of ewes lambing and relaxin (100 to 12,500 guinea-pig units/ewe) did not affect the depth to which the inseminating pipette could be inserted into the cervix.Overall lambing results (percentage of ewes lambing) for Exps 2, 3, 4 and 5 were 30·5% (266 ewes), 46·3% (231), 49·3% (69) and 27·5% (291) respectively, whereas results for the best treatment combinations in these experiments were 61·9%, 56·7%, 64·7% and 40·4%.

POTTS, D. M.; WILSON, I. B.; SMITH, M. S. R.

doi: 10.1530/jrf.0.0220425pmid: 5453374

Summary.The ultrastructure of rat blastocysts (114 hr p.c.) transferred to the uterus of pseudopregnant mice (80 hr p.c.) was observed 24 to 36 hr after transfer. The morphology of the blastocyst and of the uterine epithelium was apparently normal for the species and time of pregnancy, but the plasma membranes of the trophoblast and uterine epithelium failed to establish the intimate contact which is characteristic of the later stages of normal implantation.

WILSON, I. B.; POTTS, D. M.

doi: 10.1530/jrf.0.0220429pmid: 5453375

Summary.The passage of melanoma cells into the subepithelial tissues of a pseudopregnant mouse uterus was studied at the electron microscope level. A suspension of cells, injected through the cervix, was rapidly distributed along the length of the uterus. Within ½ to 1 hr after transfer, the melanoma cells began to establish a close relationship with the uterine epithelium. In limited areas, the passage of melanoma cells between (and possibly through) epithelial cells was observed within 1 hr of transfer. By 4 hr after transfer, large islands of melanoma cells were present beneath the uterine epithelium in antimesometrial areas of the uterus. No decidual changes were apparent. The ultrastructural changes seen in the maternal cells were similar to those in the initial stages of blastocyst implantation, but the melanoma cells behaved as individual units and passed through the epithelium more rapidly, and with less destruction, than trophoblast.

MILLS, R. C.; MORRISSETTE, M. C.

doi: 10.1530/jrf.0.0220435pmid: 5453376

Summary.Fourteen bovine ovaries of early pregnancy and nineteen of late pregnancy were perfused with citrated bovine blood. During perfusion, the venous blood was collected from each ovary before and after addition of lh and was analysed for progesterone content. Average progesterone synthesis rates were 43·37±1·12 and 4·57±0·99 μg/min before addition of lh, for ovaries of early and late pregnancy respectively, and increased to 7·43±1·98 and 7·72±1·33 μg/min, respectively, after addition of lh. There was no significant difference in the rates of progesterone synthesis between ovaries of early and late pregnancy at the 5% level and their response to lh was highly significant (P<0·01). These data indicate that a decrease in progesterone synthesis during late pregnancy in the bovine is not due to a reduction in the ability of the corpus luteum to respond to gonadotrophins.

BARKER, L. D. S.; AMANN, R. P.

doi: 10.1530/jrf.0.0220441pmid: 4989230

Summary.Immunodiffusion and immunoelectrophoretic analyses, including absorption tests, were used to determine the heterogeneity of antigens in bull spermatozoa and reproductive fluids and to characterize antisera against these antigens. Antisera were produced against bull seminal plasma, seminal vesicle fluid, cauda epididymal plasma, blood serum, washed ejaculated spermatozoa, washed cauda epididymal spermatozoa and sperm fractions. Four sperm-specific antigens were detected. One antigen was located in the sperm head, one in the sperm tail and two others were common to both the head and tail. The tailspecific antigen was detected only after mechanical rupture of washed spermatozoa. The major antigens of spermatozoa are localized in the cell membrane and acrosome. Apparently, sperm antigens were present in cauda epididymal plasma and seminal plasma. These antigens may have been released by physiologically normal spermatozoa or they may represent end products of sperm dissolution within the epididymis and vas deferens. Their presence makes immunological analyses of reproductive fluids difficult.Cauda epididymal plasma and seminal vesicle fluid shared at least two antigens not present in blood serum. These antigens in cauda epididymal plasma coated the sperm cell and probably were secreted by the caput epididymidis. Coating antigens were more tightly bound to ejaculated spermatozoa than to spermatozoa from the cauda epididymidis.

BETTERIDGE, K. J.; KELLY, W. A.; MARSTON, J. H.

doi: 10.1530/jrf.0.0220453pmid: 4989231

Summary.The ovaries of sixty-seven rhesus monkeys were examined and photographed at known stages of 121 menstrual cycles. In eighty-three cycles, ovulation was diagnosed but, in thirty-two, the ovary showed a large Graafian follicle and, in six, there was no sign of follicular or luteal activity. The diagnosis of ovulation was confirmed in thirty-four cases by the recovery of an egg or cumulus clot and in another seventeen by histological examination of the ovary. Six diagnoses were supported by evidence from serial observations of the ovary, and a further twenty-six were based on single examinations. Fifteen ovaries were photographed both before and after ovulation.The extremely variable appearance of proven ovulation points is illustrated and discussed. Morphological changes could not be detected on the surface of Graafian follicles within 24 to 48 hr of ovulation and it was impossible to predict when they would rupture. The age of a corpus luteum could not be estimated from the gross morphology of its ovulation point. Occasionally, corpora lutea were found to persist into succeeding menstrual cycles in forms that could be mistaken for recent ovulation points.The hazards of diagnosing ovulation by examining the ovaries at laparotomy can be reduced by making serial observations and photographic records.

SMITH, M. S. R.

doi: 10.1530/jrf.0.0220461pmid: 5465735

Summary.Changes in the uterus of the mouse during the oestrous cycle have been examined histochemically to demonstrate any variation in the occurrence of acid phosphatase, lipids and polysaccharide complexes (PAS-positive material) mainly with reference to the epithelium. Acid phosphatase was shown to have a distinct pattern of activity at each stage of the oestrous cycle. There was no evidence for acid phosphatase release, but a considerable build-up in large and small lysosomes was observed in the epithelium at metoestrus and di-oestrus. A different pattern was observed in the case of lipids and PAS-positive material. Lipids were found in considerable amounts at di-oestrus, pro-oestrus and metoestrus, whereas a strong PAS-positive reaction was observed at pro-oestrus and oestrus.

BRANHAM, J. M.

doi: 10.1530/jrf.0.0220469pmid: 5453377

Summary.Spermatozoa from semen centrifuged into Ficoll gradients separated into two populations. Under some conditions, they separated into flocculated and unflocculated populations. When flocculation was controlled, they separated into rapidly and slowly sedimenting populations. The centrifugal population consisted predominantly of active spermatozoa while the centripetal population contained predominantly inactive ones. Various morphologically distinct types of spermatozoa were also not randomly distributed. Experimentally inactivated, non-flocculating spermatozoa sedimented as a single population. It was concluded that flocculation and motility influenced sedimentation rate more markedly than other factors.