Oestrus in the British white goat: timing of plasma luteinizing hormone surge and changes in behavioural and vaginal traits in relationship to onset of oestrus.

Length of oestrus and timing of the LH surge was measured in six British White does, housed with a vasectomized buck (experiment 1). The following breeding season, pulsatile LH release during the cycle was measured in eight does and the pattern of behavioural and vaginal traits in relation to onset of oestrus (time 0) determined (experiment 2). In experiment 1, the interval to first oestrus after introduction of the buck on 1st October was 10.3 +/- 3.0 days (n = 6) but in experiment 2, when the buck was put in on 1st September, first oestrus occurred after 39.3 +/- 3.4 days in 7/8 does and 7 days in 1/8 does indicating that adequate exposure to short days is needed before the buck can initiate ovarian activity. LH pulse frequency increased from 0-1 pulses/8 h to 3 pulses/8 h after luteolysis, with no change in pulse amplitude, suggesting that progesterone regulates LH pulse frequency. Mean LH values rose from basal to 102.1 +/- 7.8 ng/ml, 12 +/- 1.5 h after the onset of oestrus, which was 16.3 +/- 1.7 h in length. Does sought out the buck and displayed tail wagging, bleating and restlessness from -60 h to +36 h relative to the onset of oestrus (time 0). The incidence of these activities rose at -12 h and peaked at 0 h. Tail wagging, but not bleating or restlessness, also increased in intensity at 0 h, as did the intensity with which the doe actively sought out the buck. Vulval redness and swelling and onset of a clear thin vaginal discharge were first observed 1-2 days before oestrus, becoming maximal on day 0. It was concluded that onset of frequent tail wagging was the most useful trait for detecting onset of oestrus.

Pregnancy-associated changes in the physical and microscopic characteristics of the ovine cervix.

Ovine cervices were obtained at slaughter from 18 sheep comprising six groups of three--cycling ewe lambs, non-pregnant, and four groups of pregnant animals of progressively longer gestation PI to PIV. Physical and microscopic analyses carried out on these cervices showed consistent results throughout any individual tissue. A number of factors changed with increasing gestational age and some of these changes were noted from early gestation. No significant change in water content was observed through pregnancy. With increasing length of gestation the cervix increased in length and width, there were relative increases in fibroblasts, smooth muscle and softening of the tissue, and relative decreases in collagen and fibrocytes. An increased vascularity was observed in the tissues from late gestation sheep, and a change in the nature of the epithelial secretion, from neutral to acidic mucins, was also associated with late pregnancy.

Effects of nandrolone phenylpropionate in the horse: (1) resting animal.

The effects of 7 weekly injections of the anabolic steroid nandrolone phenylpropionate (400 mg) were investigated in 4 healthy, mature geldings. Measurement of body weight, nitrogen retention and plasma urea failed to demonstrate a consistent anabolic effects. Examination of biopsies from the semitendinosus and biceps femoris muscles showed no alteration in water content or glycogen concentration with treatment. Similarly no changes were found in the activities of 6 muscle enzymes. However, a significant increase in the proportion of fast twitch low oxidative fibres of the biceps femoris was observed. The effects of the treatment on a wide range of plasma biochemical constituents were investigated. The occurrence of some components of stallion behaviour in the geldings was taken to reflect a residual androgenic activity in the compound.

Effects of nandrolone phenylpropionate in the horse: (2) general effects in animals undergoing training.

The effect of 11 weekly injections of nandrolone phenylpropionate (400 mg) was investigated by a crossover trial (2 training periods) in 6 Thoroughbred geldings undergoing training. A decrease in body weight and flank measurement occurred only during the first training period and was not modified by the anabolic steroid. Urinary nitrogen excretion was lower in the anabolic treated animals only in the first training period. Neither training nor training plus nandrolone phenylpropionate administration caused any marked alteration in blood biochemistry or haematology. A significant decrease in plasma chloride and increase in haematocrit occurred independent of treatment in the latter, more extensive anaerobic training of both parts of the crossover. No change in urinary pH or specific gravity was found throughout the study. No evidence of improved racing performance due to nandrolone phenylpropionate administration was observed. Behavioural changes attributed to the drug could be detected for at least 6 weeks after the cessation of treatment.

Effects of nandrolone phenylpropionate in the horse: (3) skeletal muscle composition in the exercising animal.

The effect of 11 weekly injections of nandrolone phenylpropionate (400 mg) on some skeletal muscle parameters was investigated in 6 Thoroughbred geldings undergoing training. Three muscles were sampled, the middle gluteal, the biceps femoris and the semitendinosus. Training alone produced increases in the percentage of fast twitch high oxidative fibres (FTH), glycogen content and the activities of citrate synthase, 3-hydroxyacl CoA dehydrogenase and cytochrome oxidase. In contrast the training programme did not alter water content, total protein content, the activities of lactate dehydrogenase, phosphofructokinase of beta glucuronidase, fibre area ratios or the number of capillaries per unit fibre area. Nandrolone phenylpropionate given in conjunction with the training programme only resulted in changes in 2 of these parameters. There was no increase in the percentage of FTH fibres in the biceps femoris with anaerobic training and the fibre area ratio increased significantly in this muscle.

Monitoring pre-service reproductive status in dairy cows.

Combinations of oestrus detection, ovarian palpation and milk progesterone assays were used to monitor pre-service reproductive status of cows in two dairy herds over two successive years. Non-cyclical cows were identified as having no luteal tissue in their ovaries on two occasions 10 days apart. Absence of luteal tissue was determined by the presence of basal mild progesterone initially followed either by a repeat of this result or by failure to palpate a corpus luteum per rectum. In the period 32 to 56 days post partum the number of non-cyclical cows on farm A years 1 and 2 was eight out of 31 (25 . 5 per cent), and 10 out of 62 (16 . 1 per cent) and on farm B years 1 and 2 was 10 out of 68 (14 . 7 per cent) and 11 out of 85 (12 . 9 per cent) respectively. The farm A herd was high yielding, (average lactation 6380 litres), whereas the farm B herd was of average yield (4717 litres). In both herds 60 day milk yield was not related to cyclical status of pre-service cows. There was however a trend toward a greater proportion of young cows being non-cyclical. With the exception of a prolonged calving to conception interval for farm A in year 1, whether a pre-service cow was cyclical or not had no effect on when the cow was first served or on when the animal conceived. The routine incorporation of pre-service monitoring to herd fertility control programmers may however be of value in recognising the incidence of non-cyclical cows and giving an early indication of oestrus detection efficiency.

Assessment of oviduct potency in the cow.

A test of oviduct patency was developed, based on instillation of dye to the uterine horn through a two-way catheter. In 23 cows, two cases of bilateral and five cases of unilateral blockage were detected. Of 69 cow genital tracts collected from an abattoir, nine of 138 oviducts (7 per cent) did not permit the passage of dye. Fourteen of the remaining oviducts were found to blocked using a suspension of 80 micrometer pollen grains. This suggested that some animals showing patency to the dye test in vivo may in fact have abnormalities of the oviduct sufficient to prevent the passage of the ovum. In five cows, superovulation and embryo recovery were carried out as an investigation of oviduct patency and function. Although in one of the five cows, subsequently found to have a blocked oviduct, no embryos were recovered, ambiguous results were obtained in the other animals. The unpredictable response to superovulation may limit the application of this latter technique in investigation of oviduct patency and function.

Some aspects of the aetiology, diagnosis and treatment of infertility in the bitch.

The nature of the infertility in 19 bitches was investigated: 10 animals were considered to be normal on the basis of their sexual behaviour, vaginal cytology and plasma oestrogen and progesterone concentrations. Successful conception and whelping occurred for 6 of the 10 bitches. The previous apparent infertility was probably attributable to defective mating management by the owners. Although follicular development and ovulation occurred in 4 of the remaining bitches, oestrus was not exhibited: AI resulted in 3 conceptions. The other 5 animals exhibited only some of the normal characteristics of pro-oestrus. Another group of 10 anoestrous bitches (normal and pathological) was treated with PMSG or stilboestrol. PMSG induced follicular development in 5 of 6 bitches treated. The magnitude of the induced plasma oestrogen peak varied considerably. Delay in the initiation of oestrous behaviour occurred relative to the plasma gonadal steroid pattern in 2 of the 3 bitches that showed oestrus. Stilboestrol induced a sequence of behavioural changes and plasma steroid concentrations and patterns similar to those found in the normal oestrous bitch, but none conceived.

Phenotypic intersex (female pseudohermaphroditism) in a dachshund dog.

A male miniature rough-haired dachshund, presented with episodic haematuria, was found to be a female pseudohermaphrodite. A littermate also had an abnormality of the urogenital tract and their dam had received a progesterone implant during pregnancy. Chromosome analysis of the intersex revealed XX/XY mosaicism in certain tissues.

Hormone producing ovarian tumours in the dog.

In two cases of granulosa cell tumours of the ovary in bitches there was production of sex hormones by the neoplasm. Both tumours produced oestrogens but one also produced significant concentrations of progesterone. In both bitches, the presenting sign was abnormally prolonged oestrus activity. One dog also developed a haemorrhagic diathesis as a result of endogenous oestrogen toxicity.

Hormonal and histological studies in a 61XXY bull.

A Friesian bull with bilateral testicular hypoplasia was diagnosed as having a pure 61XXY karyotype. The bull displayed normal sexual behaviour but was azoospermic. At 17 months, the animal's peripheral plasma androgen levels appeared to be lower than normal, and one testicle removed one month later showed small seminiferous tubules totally lacking in germ cells. The Leydig cell volume of this testis was well within the normal range but the tubule length was rather short. At 33 months of age an increase in peripheral plasma androgen levels was noted. In the remaining testis there had been both a considerable rise in Leydig cell volume and a fall in tubule length. These findings may be explained by the interaction of three factors; the effects of the abnormal karyotype, the increased maturity of the animal at 33 months and the reaction of the remaining testis to unilateral castration.

Progesterone assays and rectal palpation in pre-service management of a dairy herd.

Fifty-one dairy cows were examined three times at weekly intervals during weeks 5 to 7 after calving. Rectal palpation of the ovaries and plasma progesterone assay were used to determine cyclic ovarian function. Eight of 51 cows exhibited true anoestrus by day 49 after calving. Only 23 of 43 cycling cows were served by day 77, the end of the target period for first service. In 77 per cent of 142 examinations, rectal palpation and progesterone assay gave compatible results. Most incompatibility occurred early or late inthe cycle, or in association with cystic structures in the ovaries. Eleven of the 51 cows had cysts in the ovaries but cyclicity and fertility were not adversely affected.