Ultrasonography and hormone profiles of adrenocorticotrophic hormone (ACTH)-induced persistent ovarian follicles (cysts) in cattle.

The objective of this study was to develop a model for the study of abnormal ovarian follicles in cattle by treating heifers with adrenocorticotrophic hormone (ACTH) (100 iu at 12 h intervals for 7 days, beginning on day 15 of the oestrous cycle). Cortisol concentrations increased (P < 0.05) within 24 h after beginning ACTH treatment and cortisol and progesterone concentrations remained elevated after cessation of ACTH treatment for 8 and 4 days, respectively. The pulses and surges of LH decreased during ACTH treatment, but FSH profiles were similar to those in controls and persistent or prolonged follicles were eventually observed in all heifers. In five heifers, prolonged dominant follicles ovulated after 10 days, whereas in six heifers, persistent follicular structures were present for 20 days, but ceased to secrete oestradiol after approximately 12 days. In the heifers with persistent follicular structures, new follicles emerged when the persistent follicle became non-oestrogenic. During the last 2 days of normal follicular growth, the concentration of oestradiol was greater than it was during prolonged or persistent follicle development (P < 0.05). There were no differences in the growth rates or maximum diameters of abnormal follicles that had different outcomes, but oestradiol concentrations were greater in prolonged follicles that ovulated compared with those follicles that persisted (P = 0.06). In conclusion, stimulation with ACTH resulted in a marked deviance from normal follicular activity. The aberrations were probably caused by the interruption of pulsatile secretion of LH (but not FSH) leading to decreased but prolonged oestradiol secretion.

The role of LH pulse frequency in ACTH-induced ovarian follicular cysts in heifers.

The aim of the present study was to induce ovarian cysts experimentally in cattle using ACTH and to closely examine the role of LH pulse frequency in ovarian cyst formation. Five regularly cycling Holstein-Friesian heifers (15-18-month-old) were used. Ovaries were scanned daily using an ultrasound scanner with a 7.5 MHz rectal transducer. Daily blood samples were obtained via tail venepuncture for hormone analyses. Additional blood samples (for FSH and LH pulses) were obtained through an indwelling jugular vein catheters every 15 min for 8 h on Days 2 (early luteal phase; ELP), 12 (mid-luteal phase; MLP) and 19 (follicular phase; FP) of control estrous cycle and on alternate days during follicular cyst (FC) formation and persistence. Cysts were induced using subcutaneous injections of ACTH (Cortrosyn) Z; 1 mg) every 12 h for 7 days beginning on Day 15 of the subsequent estrous cycle. Plasma concentrations of progesterone (P4), estradiol-17beta, FSH and LH were determined by double antibody radioimmunoassay while cortisol concentration was determined by enzyme immunoassay (EIA). Ovarian follicular and endocrine dynamics were normal during the control estrous cycles. Ovarian follicular cysts were induced in four of the five heifers. Mean maximum size of cysts was larger (P<0.05) than that of ovulatory follicles (26.78+/-3.65 versus 14.1+/-0.90 mm), respectively. Cortisol levels were increased during ACTH treatment. High concentrations of estradiol and low progesterone were observed after cyst formation. LH pulse frequency was significantly reduced (P<0.05) during cyst formation and persistence compared to ELP (7.5+/-0.75) and FP (6.5+/-0.58), but was not significantly (P=0.23) different from MLP (2.8+/-0.29) pulses. Mean LH pulse amplitude and concentrations were not different. Similarly, the mean pulse frequency, amplitude and concentration of FSH were not different between control study and cystic heifers. These results suggest that the LH pulse frequency observed following ACTH treatment may interact with high estradiol concentration to induce ovarian cyst formation in heifers.

Relationship of maternal plasma progesterone and estrone sulfate to dystocia in Holstein-Friesian heifers and cows.

Thirteen primiparous and 41 multiparous Holstein-Friesian cattle were used to study the relationship between maternal plasma progesterone (P4) and estrone sulfate (E1S) concentrations and the prevalence of dystocia. The calvings in 4 heifers and 30 cows were normal (eutocia), while the calvings in 9 heifers and 11 cows were difficult (dystocia). Neither the concentrations of P4 nor E1S were different between the groups with eutocia and dystocia from days 90 to 270 of pregnancy. However, a few days prior to parturition, eutocial cows and heifers showed a sharp decline of plasma P4, while dystocial cattle did not show such a remarkable decline of P4 concentration. Plasma P4 levels in dystocial cows a few days antepartum were significantly higher than in eutocial animals (P<0.05 or P<0.01). Prepartum E1S concentrations were significantly lower (P<0.05) in dystocial than eutocial cattle during the prepartum period from days 6 to 1 in heifers and from days 3 to 1 in cows. These results suggest that insufficient production of E1S and delayed regression of the corpora lutea are possible causes of dystocia in cattle.

Lack of LH response to exogenous estradiol in heifers with ACTH-induced ovarian follicular cysts.

The aim of the present study was to examine the LH response to exogenous estradiol in 4 heifers with ACTH-induced ovarian follicular cysts. During the control experiment, administration of estradiol 24 hr after PGF2alpha in luteal phase heifers resulted in a LH response in all 4 heifers. The LH response was obtained between 16-20 hr after estradiol administration. The peak LH concentration (Mean +/- SEM; 5.1 +/- 0.8 ng/ml) during the control study was significantly different (P<0.05) from the concentration after cyst formation. None of the 4 heifers responded to estradiol after ovarian cyst formation. This result suggests that heifers with ACTH-induced ovarian follicular cysts may have a defective hypothalamio-pituitary response to exogenous estradiol similar to cows with spontaneous ovarian cysts.

The relationship between plasma oestrone sulphate concentrations in pregnant dairy cattle and calf birth weight, calf viability, placental weight and placental expulsion.

A total of 54 Holstein-Friesian cows (13 primiparous and 41 multiparous) was used to study maternal plasma oestrone sulphate (E1S) during pregnancy and its relationship to birth weight and viability of calves and time required for placental expulsion after calving. Plasma samples were obtained from the tail vein of cows once every month from days 90 to 180, every 2 weeks from days 181 to 270, and every day from day 270 of gestation to parturition. The E1S concentrations were measured by radioimmunoassay, and birth weight, placental measurements, neonatal viability and the period from calving to placental expulsion were recorded. E1S concentrations were correlated positively (0.71 > or = r > or = 0.32, P < 0.05 or P < 0.01) with calf birth weight and weights of cotyledons, intercotyledonary membranes and total placenta from days 210 of gestation to 1 day prepartum. Calf birth weight was correlated positively (p < 0.01) with the weight of the cotyledons (r = 0.87), intercotyledonary membranes (r = 0.78) and total placenta (r = 0.88). In addition, E1S concentrations were positively correlated (0.63 > or = r > or = 0.28, P < 0.05 or P < 0.01) with the neonatal viability after day 195 of pregnancy, and were negatively correlated (-0.29 > or = r > or = -0.55, P < 0.05 or P < 0.01) with the intervals from parturition to placental expulsion after 225 days of pregnancy. The results suggest that variation among dams for circulating E1S levels during late pregnancy may be caused by variation of placental development and ability for oestrogen production and conjugation, and they may influence fetal growth, neonatal viability and retained placenta.

Comparative evaluation of ovarian structures in cattle by palpation per rectum, ultrasonography and plasma progesterone concentration.

The aims of this study were to determine the relationship between the ultrasonographic determination of corpora lutea and the plasma progesterone profile of cyclic cows during an oestrous cycle, and to compare the accuracy of detection of normal and abnormal ovarian structures by ultrasonography and palpation per rectum, based on the plasma progesterone profile. The ovaries of six lactating cyclic dairy cows were scanned and blood samples were obtained three times a week for one month. There was a high correlation (r = 0.85) between the diameter of the corpus luteum and the plasma progesterone concentration, but on days -3 and -2 (oestrus = day 0) the diameter was the same as mid-luteal values but it was functionally inactive (plasma progesterone < 0.5 ng/ml). The accuracy of palpation per rectum and ultrasonography for determining the presence and age of the corpora lutea was investigated in 34 cows by using the plasma progesterone concentration and the dissection of ovaries post mortem as standards. The sensitivity, specificity and positive predictive value of palpation for identifying mid-cyclic corpora lutea were 85 per cent, 95.7 per cent and 89.5 per cent, respectively. Ultrasonography had a sensitivity of 95 per cent, a specificity of 100 per cent and a positive predictive value of 100 per cent. Twenty-nine cows were diagnosed by palpation per rectum as having either follicular or luteal cysts. During ultrasonography, an ovarian cyst was defined as a non-echogenic structure at least 5 mm in diameter.(ABSTRACT TRUNCATED AT 250 WORDS)

Ultrasound and progesterone monitoring of ovarian follicular cysts in cows treated with GnRH.

Five cows, diagnosed as having follicular cysts (by palpation per rectum, ultrasonography and progesterone determination), were treated with 0.5 mg gonadotrophin releasing hormone (GnRH) 10 days after initial diagnosis. The ovaries were scanned weekly from the day of treatment (day 0) until day 35. Mean (+/- SEM) plasma progesterone concentration on the day of diagnosis (day -10) and day 0 were 0.2 +/- 0.13 ng ml-1 and 0.72 +/- 0.27 ng ml-1, respectively. Elevated progesterone (5.58 +/- 0.67 ng ml-1) was found in all cows by day 7 after treatment. Changes noted during weekly ultrasonography included clouding of the uniformly nonechogenic (dark) antrum of cysts, luteinization of the cyst wall, reduction in cyst size (cyst resolution) and/or development of 1-4 corpora lutea in the ovary bearing the cyst or in the contralateral ovary. Oestrus was observed in all cows 18.8 +/- 1.74 days after treatment. It is concluded that ultrasonography and progesterone determination are useful tools for veterinarians in the monitoring of responses of follicular cysts to treatment.

An abattoir survey of female genital disorders of imported camels (Camelus dromedarius) in Kano, Nigeria.

An abattoir survey of 850 female genital organs of imported camels was conducted at the Kano abattoir between October 1987 and April 1988. An incidence of 4.49% of disorders was recorded, including follicular cystic degeneration (0.12%), ovarian haemorrhagic cysts (0.47%), pyometra (0.35%), early embryonic mortality (0.12%), endometrial haemorrhages (0.47%), fetal maceration (0.12%), abscess (0.24%), vulvar tick infestation (1.77%) and cervical hypoplasia (0.12%).