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P. E. MATTNER

Leucocytes containing ingested spermatozoa have been found in the female genital tract in small laboratory animals (McDonald, Black, McNutt & Casida, 1952; Austin, 1957; Yanagimachi & Chang, 1963), in pigs (Pitkjanen, 1960) and in ruminants (Howe & Black, 1963; Mattner, 1968). Using electron microscopy, Bedford (1965) found that the cell membranes and acrosomal cap remained intact in many of the spermatozoa present within leucocytes obtained from the uteri of oestrous rabbits inseminated 12 hr previously. The latter finding indicates that leucocytes may ingest undamaged, living spermatozoa as well as dead or damaged spermatozoa in the female genital tract. The present communication reports visual observations on the ingestion of motile spermatozoa in bovine cervical mucus and the failure of leucocytes to attack dead spermatozoa in the same medium.

Cervical mucus containing numerous polymorphonuclear leucocytes was obtained from cows in late oestrus. Threads of mucus and bovine semen were placed in

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P. E. MATTNER

Summary.

Quantitative studies were made of the distribution of spermatozoa and leucocytes in the female genital tract of mated goats and cows near the time of ovulation and of the leucocytes in the genital tract of unmated goat does at a similar time. In both species, the cervix appeared to act as a reservoir for spermatozoa. Spermatozoa were not uniformly distributed through the lumen of the cervix but tended to be aggregated in the vicinity of the cervical mucosa.

The presence of spermatozoa in the genital tract resulted in an increased number of leucocytes in the lumen of the uterus and cervix. In the cervix, the majority of the leucocytes occurred in the central mass of the mucus, this being consistent with the main invasion of the cervical mucus by the leucocytes taking place from the uterus. The resulting separation of spermatozoa and leucocytes in the cervix is probably an important factor in the survival of an adequate population of spermatozoa in the cervix of ruminants after mating.

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P. E. MATTNER

Summary.

The effect of spermatozoa within the cervix and of spermatozoa within the uterus on the infiltration of polymorphonuclear leucocytes (polymorphs) into the lumen of the genital tract at oestrus was examined in ewes. Ligation of the cranial end of the cervix resulted in an accumulation of polymorphs in the lumen of the uterus and of fewer polymorphs in the lumen of the cervix. In genital tracts so ligated, spermatozoa within either the cervix or the uterus had no material effect on the number of polymorphs found in the cervix. The presence of spermatozoa in ligated uterine horns caused an increase in the number of polymorphs migrating into the lumina of the horns, the response being manifest within 5 hr. The results indicate that drainage of polymorphs from the uterus into and through the cervix is a normal occurrence in ruminants which may reduce the incidence of phagocytosis of spermatozoa in the uterus.

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P. E. MATTNER

Summary.

Bull spermatozoa survived at extremely low cell concentrations (10 to 470 cells/μl) at 37° C in either cervical mucus or gel obtained by centrifugation of the mucus, but became immotile almost immediately after being suspended at 500 cells/μl in isotonic saline. Spermatozoa were adversely affected by suspension at low cell concentration in supernatant obtained by centrifuging mucus, or in mucus that had been liquefied by maceration. Although spermatozoa were slightly more resistant to the lethal effects of dilution in saline after passage through mucus, the resistance was quickly lost. The results suggest that the structural and physical properties of the mucus are responsible for the absence of the dilution effect on spermatozoa in cervical mucus.

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P. E. MATTNER and G. D. THORBURN

It is uncertain whether ovarian bloodflow in ewes remains constant or varies with the stage of the oestrous cycle. In an experiment in which `minimal estimates' of the ovarian steroid secretion rates were obtained, Short, McDonald & Rowson (1963) cannulated the "major vein draining the corpus luteum or ripe Graafian follicle". The bloodflow rates obtained were lower in oestrous than in di-oestrous ewes. Moore, Brown & Smythe (1965) using a similar technique did not find that the rates varied cyclically.

In the present study, seventeen Merino and five Corriedale ewes were used. They were 5 to 7 years old and had regularly exhibited oestrus at intervals of 17 days. Anaesthesia was induced and maintained with sodium pentobarbitone except on nine occasions when anaesthesia was maintained with fluothane. The abdomen was opened by

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J. K. VOGLMAYR and P. E. MATTNER

It is well known that in many mammalian species, including the sheep (Sundaram & Stob, 1967), unilateral ovariectomy leads to compensatory hypertrophy in the remaining ovary and an ovulation rate equal to that of the two ovaries in the control animals (Parkes, 1966). However, it has not been conclusively established that analogous compensatory changes occur in the remaining testis following unilateral orchidectomy. Although it has been shown in the hemicastrated adult rat that the remaining testis enlarges (Grant, 1957) and the epididymal sperm reserve increases to that of the two epididymides in the intact animals (Smelser, 1933), observations on the hemicastrated rabbit (Edwards, 1940) and other species (see Parkes, 1966) are conflicting. Previous studies were limited because of the lack of a technique for accurately assessing production

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B. W. Brown, M. J. Emery and P. E. Mattner

Summary. Changes in the mean velocity of ovarian arterial blood flow during the oestrous cycle were monitored in 5 ewes by the use of Doppler ultrasonic transducers chronically implanted around the ovarian arteries. In arteries supplying ovaries with a corpus luteum (CL), the velocity was minimal from Day −1 to Day 2 inclusive (Day 0 = day of oestrus), increased steadily until Day 13 (−4) and then declined precipitously. In contralateral arteries supplying ovaries without a CL, the velocity remained at a consistently low level throughout the oestrous cycle.

In each ewe, arterial blood velocity to the ovary with a CL and progesterone levels in peripheral plasma were highly correlated; within-individual correlations falling between r = 0·830 (P < 0·001, n = 15) and r = 0·936 (P < 0·001, n = 15). The changes in the velocity of the arterial supply to the ovulatory ovary and the plasma progesterone levels during the luteal stage of the cycle followed a similar pattern to that for weight of luteal tissue in similar ewes.

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H. M. Radford, C. D. Nancarrow and P. E. Mattner

Summary. Two groups, each of 7 crossbred beef cows, which were suckling or not suckling calves, were fed a high quality food ad libitum for 3 months post partum. The non-suckling cows experienced regular ovarian cycles from 10–33 days post partum while the suckling cows did not do so until at least 14 weeks post partum. There was little difference between the groups in growth rate or in plasma glucose concentration. The plasma prolactin concentrations in the non-suckling cows showed a seasonal trend which paralleled ambient temperature and daylight hours; in the suckling cows this trend was less evident. Plasma LH concentrations were lower in suckling cows before Day 30 post partum but were similar thereafter. Most suckling cows also failed to experience oestrus or to exhibit LH release in response to an injection of oestradiol benzoate at about 6 weeks post partum. This failure, together with the earlier lower levels of LH in the suckling cows, is considered to be indicative of malfunction of the hypothalamic mechanism normally responsible for the establishment and maintenance of cyclic ovarian function.

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P. E. Mattner, B. W. Brown and J. R. S. Hales

Summary. Vessels with histological features characteristic of arterio–venous anastomoses were found in the stroma but not in CL. In 5 conscious ewes at the mid-luteal stage of the oestrous cycle, ovarian blood flow was significantly greater (P < 0·025) with microspheres of 50 than of 15 μm diameter in ovaries without CL (0·23 ± 0·04 (s.e.m.) and 0·11 ± 0·02 ml/min, respectively), but not in ovaries with CL (4·42 ± 0·86 and 3·73 ± 0·70 ml/min, respectively). In 5 similar but anaesthetized ewes, the portion of each ovarian artery within the ovarian vascular pedicle was bypassed with re-entrant catheters through which microspheres were perfused. A greater proportion (P < 0·01) of 50 than of 15 μm microspheres was retained in ovaries with (90 and 79%) or without (82 and 45%) a CL.

It is concluded that functional arterio–venous anastomoses are present in sheep ovaries.

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B. W. Brown, P. E. Mattner, P. A. Carroll, R. M. Hoskinson and R. D. G. Rigby

Groups of Merino ewe lambs were immunized against GnRH either soon after birth (prepubertal) or around puberty (peripubertal) with a prototype commercial preparation and were studied over the following 2 years to determine the long-term effects on reproductive development, function and hormone concentrations. At least 60% of the GnRH-immunized ewes in either treatment group did not experience oestrus and possessed small uteri and small ovaries that lacked follicular development. Growth rates of immunized and control ewes were similar throughout the study. Compared with the increase in plasma LH and FSH concentrations with age in control ewes, the concentrations of these hormones in immunized animals were lower and remained relatively constant from 46 to 90 weeks of age. Plasma FSH concentrations were particularly suppressed in immunized ewes and were significantly (P < 0.05) lower than the control values of 61 and 90 weeks of age. LH release after injection of 1 μg GnRH at 90 weeks of age was either absent or suppressed in immunized ewes compared with controls. The findings suggest that the lack of GnRH stimulation and consequent deprivation of gonadotrophins, early in the life of ewes, may result in some degree of permanent impairment of hypothalamic and/or pituitary function.