Epidural vs intramuscular administration of lecirelin, a GnRH analogue, for the resolution of follicular cysts in dairy cows

Bovine follicular cysts are an ovarian disorder of dairy cows associated with abnormal estrous behaviour and infertility. The treatment of choice is intramuscular administration of a GnRH analogue, which acts by triggering pituitary release of LH. However, the presence of GnRH and GnRH receptors on spinal cord and ovary in some species, and the kind of innervation of the ovary, let us hypothesize that GnRH and its analogues may also act when administered by epidural route, as happens for other drugs. Therefore the aim of this study was to compare the effects of epidural vs intramuscular administration of lecirelin (a GnRH analogue) on FC regression, estrus detection and pregnancy outcomes. The study was conducted on 220 Friesian cows affected by follicular cysts, divided among 4 groups: Group L(epid) and Group L(im) received, respectively 50 μg of lecirelin in the epidural space and intramuscular; Group C(epid) and Group C(im) were used as control groups. In Group L(epid), estrus induction and pregnancy rates were significantly higher than in Group L(im). The results of this study show that the epidural administration of lecirelin promoted the remission of follicular cysts and an improvement of reproductive parameters compared to intramuscular administration. Thus, an alternative therapeutical approach is available for FC treatment, in order to obtain an easier restoration of the ovarian activity, especially in those cases refractory to classical therapeutic approaches.     

In vivo and in vitro studies of the role of the adrenergic system and follicular wall contractility in the pathogenesis and resolution of bovine follicular cysts

Bovine follicular cysts (FCs) are a common cause of economic loss in modern dairy herds. Their aetiopathogenesis is not completely understood, even though an inadequate hypothalamic release of GnRH at the time of ovulation is considered to be their main cause. Much evidence, however, suggests a role for adrenergic innervation in ovarian functions, such as follicular development, steroid hormone secretion, and follicular contractility, the latter being an event important for ovulation. Moreover, in humans, polycystic ovary syndrome, a disease very similar to bovine follicular cysts, is characterised by increased density of adrenergic nerves. Given these premises, the aim of our study was to evaluate the effectiveness and mode of action of a novel strategy for the treatment of bovine follicular cysts. In the in vivo experiment, 170 Friesian cows diagnosed with follicular cysts were assigned to four groups (groups A, B, C, and D) to assess the effects of epidural administration of a β-adrenergic antagonist (carazolol) alone or in combination with a GnRH analogue (lecirelin). The four groups underwent the following treatments: Group A was administered lecirelin in combination with carazolol; Group B was administered carazolol; Group C was administered lecirelin; and Group D was administered only normal saline solution. In the in vitro experiment, strips of the walls of cystic follicles recovered post-mortem were suspended in an organ bath, connected to an isometric force transducer and exposed to increasing doses of epinephrine or to the same treatment after exposure to carazolol for 15 min (n = 10). The amplitude and frequency of the contractile activity were recorded. None of the control cows was observed in oestrus or was submitted to AI. The combination of lecirelin and carazolol induced a significant increase in the number of cows in oestrus (88%) compared to lecirelin alone or to carazolol alone (P < 0.05 and P < 0.01, respectively). The combination of lecirelin and carazolol and lecirelin alone were significantly more efficacious than carazolol alone (P < 0.01 and P < 0.05, respectively). In the in vitro experiment, epinephrine increased the amplitude of the contractions of the strips in a dose-dependent manner. This response was significantly enhanced in strips pre-treated with carazolol. The treatments had no effect on the frequency of contractions. In conclusion, our work demonstrates that the epidural administration of a GnRH analogue and a β-adrenergic blocker is an effective means of treating cows with cystic ovarian disease. Moreover, it confirms, from a clinical point of view, that alterations of the adrenergic system and of the contractility of the follicular wall can be considered aetiopathogenic factors involved in the development of FCs. The results of this study lay the basis for a new therapeutic approach to FCs.     

Reproductive performance of dairy cows with luteal or follicular ovarian cysts after treatment with buserelin

In dairy farm management economic losses resulting from cystic ovarian degeneration are well known. In spite of this, neither the definition nor the aetiopathology of ovarian cysts are clear and agreed upon. Also the usual classification in luteal and follicular cysts, requiring ultrasound examination together with assessment of P4 to be accurate, is not very helpful in field conditions. Consequently a single treatment is often provided for both types of cysts, and since the 1970s treatments with GnRH and its analogues have been considered very useful. Nevertheless differences in recovery rates after GnRH treatment in animals with either luteal or follicular cysts are reported. Thus, the aim of this study was to evaluate recovery rate, recovery time and conception rate after treatment with buserelin (GnRH-analogue) in cows with ovarian luteal or follicular cysts. In a 5 years period, 150 cows with cysts out of a total of 990 animals, were detected and treated intravenously between 45 and 60 days PP with 20μg buserelin. No statistically significant differences were found in recovery rates and in conception rates between the two types of cysts. Comparison of recovery times showed significantly shorter recovery for cows with luteal cysts. The results emphasise the usefulness of GnRH to treat ovarian cysts regardless of their type, in relation to both recovery and conception rates. Intervals from treatment to resumption of ovarian activity were affected by the characteristics of ovarian cysts, with a faster recovery for the luteal type.     

Reproductive performance of dairy cows with ovarian cysts after different GnRH and cloprostenol treatments

Cystic ovarian disease is an important cause of reproductive failure and economic loss for the dairy industry. This report describes two consecutive studies. The objective of the first was to evaluate the response of cows with ovarian cysts to two therapeutic treatments. In the second study, we compared the effectiveness of the best treatment established in Study 1 with that of the Ovsynch protocol. For Study 1, cows were considered to have an ovarian cyst if it was possible to observe a single follicular structure with a follicular antrum diameter > 25 min in the absence of a corpus luteum in three ultrasonographic examinations performed at 7 days intervals. At diagnosis (Day 0), cows were assigned to one of two treatment groups. Cows in Group GnRH/CLP (n = 31) were treated with 100 microg GnRH i.m. and 500 microg cloprostenol (CLP) i.m. on Day 14. Cows in Group GnRH-CLP/CLP(n = 32) were treated with 100 microg GnRH i.m. plus 500 microg CLP i.m. on Day 0, and 500 microg CLP i.m. on Day 14. The animals were inseminated at observed estrus and monitored weekly by ultrasonography for 4 weeks or until Al. Cows in the GnRH-CLP/CLP group showed a lower cystic persistence rate (15.6% < 45.2%; P = 0.01); a higher estrus detection rate (84.4% > 41.9%; P < 0.0001); a higher ovulation rate (75% versus 32.3%; P < 0.0001) and a higher early response rate (31% > 3%; P = 0.02) than those in the GnRH/CLP group. For the second study, 128 cows with ovarian cysts were randomly assigned to one of two treatment groups: cows in Group Ovsynch (n = 64) were treated with 100 microg GnRH i.m. on Day 0, 500 microg CLP on Day 7, and 100 microm GnRH i.m. 36 h later. Cows in this group were inseminated 24 h after the second GnRH dose (Ovsynch protocol). Cows in Group GnRH-CLP/CLP/GnRH (n = 64)were treated as those in the GnRH-CLP/CLP group of Study 1 but received GnRH 32 h after the second CLP treatment and were inseminated 24 h after this. A further group of cows without ovarian cysts inseminated at natural estrus served as the Group Control (n = 64). Cows in the GnRH-CLP/CLP/ GnRH group showed a lower cystic persistence rate (10.9% < 46.9%; P < 0.0001); higher ovulation rate (79.7% > 17.2%; P < 0.0001); higher return to estrus rate (34.3% > 12.5%; P < 0.01) and higher pregnancy rate (28.1% > 3.1%; P < 0.01) than those in Ovsynch; and a similar pregnancy rate (28.1% versus 35.9%) to Control cows. These findings indicate that lactating cows with ovarian cysts can be successfully synchronized and time inseminated using a protocol that combines GnRH and CLP, starting treatment by simultaneously administering both products. This protocol also allows the insemination of cows showing estrus within the first week of treatment. Ovarian cysts were less responsive when treatment was started with GnRH alone.     

An alteration in the hypothalamic action of estradiol due to lack of progesterone exposure can cause follicular cysts in cattle

Many mammals, including cattle, can develop ovarian follicular cysts, but the physiological mechanisms leading to this condition remain undefined. We hypothesized that follicular cysts can develop because estradiol will induce a GnRH/LH surge on one occasion but progesterone exposure is required before another GnRH/LH surge can be induced by estradiol. In experiment 1, 14 cows were synchronized with an intravaginal progesterone insert (IPI) for 7 days, and prostaglandin F(2alpha) was given on the day of IPI removal. Estradiol benzoate (EB; 5 mg i.m.) was given 3 days before IPI removal to induce atresia of follicles. Cows were given a second EB treatment 1 day after IPI removal to induce a GnRH/LH surge in the absence of an ovulatory follicle. All cows had an LH surge following the second EB treatment, and 10 of 14 cows developed a large-follicle anovulatory condition (LFAC) that resembled follicular cysts. These LFAC cows were given a third EB treatment 15 days later, and none of the cows had an LH surge or ovulation. Cows were then either not treated (control, n = 5) or treated for 7 days with an IPI (n = 5) starting 7 days after the third EB injection. Cows were treated for a fourth time with 5 mg of EB 12 h after IPI removal. All IPI-treated, but no control, cows had an LH surge and ovulated in response to the estradiol challenge. In experiment 2, cows were induced to LFAC as in experiment 1 and were then randomly assigned to one of four treatments 1) IPI + EB, 2) IPI + GnRH (100 microg), 3) control + EB, and 4) control + GnRH. Control and IPI-treated cows had a similar LH surge and ovulation when treated with GnRH. In contrast, only IPI-treated cows had an LH surge following EB treatment. Thus, an initial GnRH/LH surge can be induced with high estradiol, but estradiol induction of a subsequent GnRH/LH surge requires exposure to progesterone. This effect is mediated by the hypothalamus, as evidenced by similar LH release in response to exogenous GnRH. This may represent the physiological condition that underlies ovarian follicular cysts.     

Influence of intrauterine infections and follicular development on the response to GnRH administration in postpartum dairy cows

The effects of intrauterine infections and prior follicular development on the response to gonadotropin releasing hormone (GnRH) administration in postpartum dairy cows were studied. Fifty lactating Holstein cows were assigned at random to one of two groups after calving. Group I (control) consisted of 25 cows given a single intramuscular injection of saline on Day 15 postpartum. Group II (treated) consisted of 25 herdmates given a single i.m. injection of 100 mug of GnRH on Day 15 postpartum. Palpation per rectum and real-time ultrasonography were used to monitor ovarian activity, and endometrial swabs were cultured to determine the presence of uterine infection. Blood samples were collected for progesterone (P(4)) and luteinizing hormone (LH) analysis. Fourteen cows (control, n = 5; treated, n = 9) did not ovulate during the first 60 d postpartum. Ovaries in these cows contained 4 to 8-mm size follicles and both P(4) and LH remained at basal concentrations. Fourteen other cows (control, n = 6; treated, n = 8) ovulated by Day 15 postpartum. Follicles >/= 10 mm were demonstrable in the ovaries of these cows before or by Day 12 postpartum. GnRH treatment had no effect on the lifespan of the existing corpus luteum in these cows. In the remaining cows, 7 of 14 Control and all 8 Treated cows ovulated within 3 d of treatment. All cows ovulating within this period were free of uterine infection and the ovaries contained follicles 相似文献   

A CIDR-based timed AI protocol can be effectively used for dairy cows with follicular cysts

The present study evaluated whether a controlled internal drug release (CIDR)-based timed AI (TAI) protocol could be used as an efficient tool for the treatment of ovarian follicular cysts in lactating dairy cows. In the first experiment, lactating dairy cows diagnosed with follicular cysts were randomly assigned to two treatments: (1) a single injection of GnRH at diagnosis (Day 0) and AI at estrus (AIE) within 21 days (GnRH group, n=70), or (2) insertion of a CIDR device containing progesterone and an injection of GnRH on Day 0, PGF(2alpha) injection at the time of CIDR removal on Day 7, GnRH injection on Day 9, and TAI 16h after the GnRH injection (CIDR-based TAI group, n=65). Conception rate after the CIDR-based TAI protocol (52.3%) was greater (P<0.05) than that after AIE following a single GnRH injection (26.9%). In the second experiment, lactating dairy cows diagnosed with follicular cysts (Cyst group, n=16) and cows having normal estrous cycles (CYC group, n=15) received the same treatment: a CIDR device containing progesterone and an injection of GnRH on Day 0, PGF(2alpha) injection at the time of CIDR removal on Day 7, and GnRH injection on Day 9. The proportion of cows with follicular wave emergence and the interval from treatment to follicular wave emergence did not differ (P>0.05) between groups. The mean diameters of dominant follicles on Days 4 and 7 as well as preovulatory follicles on Day 9, and the synchrony of ovulation following the second injection of GnRH did not differ (P>0.05) between groups. These data suggest that the CIDR-based TAI protocol results in an acceptable conception rate in dairy cows with follicular cysts.     

Follicular and endocrinological turnover associated with GnRH induced follicular wave synchronization in Indian crossbred cows

The goal of this study was to record the hormonal and follicular turnover in Jersey crossbred cows when subjected for follicular wave synchronization using GnRH. Six healthy, non-lactating and regularly cycling Jersey crossbred cows (5-6 y) were used for the study. In the control group, the follicular wave pattern was ultrasonographically investigated in 18 cycles (3 cycles/cow). In the treatment group, GnRH analogue (buserelin acetate 10 μg im) was administered on Day 6 of the cycle and follicular wave pattern was studied in 12 cycles (2 cycles/animal). Follicular population was categorized based on their diameter Class I, ≤5 mm; Class II, >5-<9 mm; Class III, ≥9 mm) and the number of follicles in each category was determined on Day 6, Day 8 and Day 10. Plasma FSH and progesterone concentrations were estimated in both control and treatment groups. Out of 18 estrous cycles studied, 14 cycles (77.8%), three cycles (16.7%) and one cycle (5.6%) exhibited three-, two- and four-follicular waves per cycle, respectively. It was evident that the DF of Wave I established its dominance and was in the growing phase by Day 6 of the estrous cycle in all the normally cycling crossbred cows. The DF ovulated in all the animals (100%) in the mean interval of 27.7 ± 0.2 h after GnRH administration. A synchronized homogenous group of follicles emerged two days after GnRH injection (Day of 8.0 ± 0.0) in all the animals (100%). The combination of LH surge induced ovulation of DF (abrupt termination of Wave I) and FSH surge stimulated homogenous recruitment of Class I follicles, led to a synchronized emergence of follicular wave. All the GnRH treated cows had three follicular waves because of early emergence and short period of dominance of Wave II DF.     

Ovarian responses and FSH profiles at superovulation with a single epidural administration of gonadotropin in the Thai-Holstein crossbreed

The conventional method of ovarian superstimulation requires multiple injections of gonadotropins which is time-consuming and may be stressful for the cows. This study was designed to determine whether a single epidural injection of FSH (EI group) would induce the superovulatory response in the Thai-Holstein crossbreed and evaluate FSH plasma hormone concentrations. Eight cows (replication = 3; n=24) were assigned to one of 2 treatments in switch back design. Control group (n=12): cows were received 400 mg FSH twice daily by intramuscularly for 4 days (80, 80, 60, 60, 40, 40, 20 and 20 mg), EI group (n=12): cows were received 400 mg FSH by single epidural injection. Data were collected in term of ovarian follicle responses, superovulatory responses, ova/embryo collection. FSH concentrations were examined using ELISA. The total follicular responses during oestrus were not different between treatments; however, the large follicles were less frequent (P < 0.01) while the medium follicle sizes were higher (P < 0.05) in the EI group. The plasma concentration of FSH in EI was dramatically increased within 2 hours before decreasing sharply thereafter (P < 0.01) and did not remain above baseline after 10 hours of administration. The embryo quality was better in the control than the EI groups (P < 0.05). Interestingly, the number of ovulation cysts in the EI group was 50%. The ovarian responses and embryo quality in the cows with cysts were worse compared with the non-cyst groups (P < 0.05). In conclusion, alternative protocols decreased the superovulatory response and increased poor embryo quality in Thai-Holstein crossbred. Also, the incidence of ovarian follicular cysts is higher in the EI group.     

Use of GnRH agonist implants for long-term suppression of fertility in extensively managed heifers and cows

The ability of gonadotrophin releasing hormone (GnRH) agonist implants to suppress ovarian activity and prevent pregnancies, long-term, was examined in heifers and cows maintained under extensive management. At three cattle stations, heifers (2-year-old) and older cows (3- to 16-year-old) were assigned to a control group that received no treatment, or were treated with high-dose (12 mg, Station A) or low-dose (8 mg, Station B and Station C) GnRH agonist implants. The respective numbers of control and GnRH agonist-treated animals (heifers + cows) at each station were: Station A, 20 and 99; Station B, 19 and 89; Station C, 20 and 76. Animals were maintained with 4% bulls and monitored for pregnancy at 2-monthly intervals for approximately 12 months. Pregnancy rates for control heifers and control cows ranged from 60-90% and 80-100%, respectively, depending on the study site. The respective number of animals (heifers + cows) treated with GnRH agonist that conceived, and days to first conception, were: Station A, 9 (9%) and 336 +/- 3 days; Station B, 8 (10%) and 244 +/- 13 days; Station C, 20 (26%) and 231 +/- 3 days. Treatment with high-dose GnRH agonist prevented pregnancies for longer (approximately 300 days) than treatment with low-dose GnRH agonist (approximately 200 days). In the majority of heifers and cows treated with GnRH agonist, ovarian follicular growth was restricted to early antral follicles (2-4mm). The findings indicate that GnRH agonist implants have considerable potential as a practical technology to suppress ovarian activity and control reproduction in female cattle maintained in extensive rangelands environments. The technology also has broader applications in diverse cattle production systems.     

Gonadotropin releasing hormone treatment of dairy cows with ovarian cysts. I. Gross ovarian morphology and endocrinology

Dairy cows diagnosed as having ovarian cysts were assigned to receive either sterile water or 100 mug GnRH (5 cows/group). Immediately prior to treatment and three days post-treatment, ovaries were observed via paralumbar laparotomy, photographed and visible structures and ovarian size recorded. Nine to thirteen days post-treatment, ovaries were removed. Blood plasma was collected for hormone determinations prior to each surgery, 1.5 and 3.0 hours and 1, 5 and 9 days post-treatment. Although concentrations were similar between groups prior to treatment, concentrations of progesterone were higher and LH and estradiol-17beta lower for GnRH treated cows than control cows, immediately prior to ovariectomy. A layer of luteal tissue approximately 5 mm thick was present around the periphery of the cystic structure at ovariectomy in 4 of 5 GnRH treated cows, but in only one control cow. The thickness of the luteal layer around the periphery of the ovarian cysts was correlated -.82, .78 and -.63 with estradiol-17beta, progesterone and LH, respectively. In summary, response to GnRH treatment in cows with ovarian cysts appears to be characterized in most cases by luteinization of the cystic structures.     

The effect of interval from day of administration of bovine somatotropin (bST) to synchronization of ovulation and timed-insemination on conception rate of dairy cows with and without ovarian cysts

The objective of this study is to evaluate the effect of the interval from the day of administration of bovine somatotropin (bST) to the day of initiation of synchronization of ovulation (Day 0 and 7) and timed-insemination (TAI) on conception rate (CR) of dairy cows with and without ovarian cysts, respectively. Lactating dairy cows (n = 359) were divided into two groups. Cows in Group 1 (n = 238, without ovarian cysts) were treated with 100 microg, i.m. GnRH on Day 0; 25 mg, i.m. PGF2a on Day 8. 100 mirog. i.m. GnRH on Day 10; and inseminated 16 h later without detection of estrus. Cows in Group 2 (n = 121, with ovarian cysts) were treated with 100 microg, i.m. GnRH on Day 0; 100 microg, i.m. GnRH on Day 7; 25 mg, i.m. PGF2alpha on Day 14, 100 ug, i.m. GnRH on Day 16; and inseminated 16 h later without detection of estrus. Between 60 and 63 days postpartum, all cows in the herd were given bST every 14 days for the duration of the study. Logistic regression was used to assess the risk of nonpregnancy associated with interval from bST treatment to Day 0 for cows without ovarian cysts. and both Day 0 and 7 for cows with ovarian cysts adjusting for parity and days in milk. The CR for cows in Group 1 was significantly higher when the interval from last treatment with bST to Day 0 was between 1 and 3 days (28%) compared to 4-6 days (14%). In addition, the risk of nonpregnancy was 2.19 times greater in cows 4-6 days after bST treatment compared to 1-3 days after adjusting for parity and days in milk. The CR for cows in Group 2 was not significantly different when the interval from last treatment with bST to both Day 0 and 7 was between 1 and 3, 4 and 6, and 7 and 14 days. In conclusion, the results of this study suggested bST treatment closer to Day 0 had a positive effect on CR of cows without ovarian cysts, but bST treatment closer to both Day 0 and 7 had no effect on CR of cows with ovarian cysts. This was interpreted to mean that bST had a beneficial effect on either, or both, the preovulatory follicle and the oocyte in dairy cows without ovarian cysts, but not in dairy cows with ovarian cysts.     

Gonadotropin releasing hormone treatment of dairy cows with ovarian cysts: II. Histology of ovarian cyst walls

Dairy cows known to have ovarian cysts were assigned to receive either sterile water or 100 μg GnRH (5 cows/group). The ovaries were removed 9 to 13 days post-treatment and prepared for histologic study. The cyst walls of ovaries removed from cows following GnRH treatment were 2 to 15 times thicker than those from cows treated with water due to apparent luteinization of cells of theca interna. Following GnRH treatment, the cells in the outermost portion of the theca interna exhibited the greatest morphologic evidence of secretory activity whereas the innermost zone was hyalinized due to poor blood supply. The luteal cells in ovarian cystic cows treated with GnRH were similar to the small luteal cells in normal corpora lutea. In summary, GnRH treatment of cows with ovarian cysts appeared to induce luteinization of the cells in the outermost portion of the theca interna.     

Response to synthetic gonadoliberin (GnRH) in anestrous cows

Fifty-three anestrous cows of Hariana crossed with Holstein, Friesian, Brown Swiss or Jersey half-breed crosses were treated with Buserelin acetate aqueous solution 0.0042 mg/ml, administered as a single intramuscular (i.m.) dose of 21 ng. Twelve (22.64%) animals exhibited complete follicular development, ovulation and behavioural expression of oestrus. Twenty-eight (52.83%) cows showed only partial follicular development with no ovulation or oestrous manifestations. Thirteen (24.53%) animals did not respond. Of eight control animals, three (37.50%) showed partial follicular development and no ovulation or symptoms of oestrus while five (62.50%) did not respond.In GnRH-treated cows showing follicular development, oestrous manifestation, and ovulation, nine animals responded between 4 to 10 d after administration. Three animals took from 14 to 155 d. The mean time from treatment to response for this group was 29.17 d. In animals showing partial follicular development and no oestrous behaviour, the interval was 3 to 11 d in 28 animals. In the control group, three animals showed partial follicular development on 94 d average. The administration of GnRH in anestrous cows promoted the development of follicles to a certain stage as evident from the clinical observations, but the follicles failed to grow beyond a particular stage. The reasons for failure of follicular development beyond a particular stage in GnRH-treated animals are not clear. It appeared that the response to GnRH may be expected to peak by the eleventh day and a second dose may then be tried for a favourable response.     

A comparison of adrenal gland function in lactating dairy cows with or without ovarian follicular cysts

Two experiments were conducted to determine if adrenal secretion of steroids differed between cows that formed ovarian follicular cysts and normal cycling cows. In experiment 1, lactating Jersey and Holstein cows were diagnosed as having ovarian follicular cysts (follicle diameter >or=20 mm) by rectal palpation. Following diagnosis, ovaries were examined by transrectal ultrasonography three times weekly to detect subsequent ovulation (n=8) or new cyst formation (n=9). Venous blood samples were collected daily to quantify circulating concentrations of cortisol and progesterone. The average concentration of cortisol during the 10-day period prior to ovulation was not different from the concentration prior to the formation of a new cyst. In experiment 2, secretion of cortisol and progesterone was examined in cows with ovarian follicular cysts (n=4) and cyclic, control cows in the follicular phase of the estrous cycle (n=4). An adrenocorticotropic hormone (ACTH) challenge was administered to cystic cows 4-7 days after new cyst formation and to cyclic cows in the follicular phase of the cycle (36 h after induction of luteolysis). Jugular venous blood samples were collected at -60, -30, 0, +10, +20, +30, +60, +90, +120, +180, +240, +300 and +360 minutes relative to ACTH administration. A rapid increase in both cortisol and progesterone was observed immediately following administration of ACTH in each treatment group. Peak concentrations of both steroids were achieved within 60 minutes after administration of ACTH. Concentrations of cortisol and progesterone did not differ between cystic and cyclic cows. In summary, no differences in adrenal function were detected between normal cycling cows and cows with ovarian follicular cysts.     

Evaluation of the effect of GnRH on follicular ovarian cysts in dairy cows using trans-rectal ultrasonography

The objectives of this study were to evaluate ovarian changes in cows with follicular ovarian cysts following treatment with either GnRH or saline. The parameters determined were the intervals from treatment to observation of a CL and from treatment to disappearance of the cyst, and the association between serum concentrations of LH, FSH and the LH/FSH ratio, before and after treatment, with the test intervals. Thirty-nine cows were identified as having follicular cysts. The GnRH treatment induced a significant increase in LH and the LH/FSH ratio. The gonadotropin response was not associated with the intervals from treatment to CL detection or to disappearance of the cyst. Survival curves for the intervals from treatment to CL detection and cyst disappearance indicate that treatment with GnRH or saline did not yield significantly different results for either parameter. The results question the efficacy of treating cystic ovarian disease with GnRH.     

Effects of an analog of PGF2(alpha) (ONO-1052) on cows with luteinized ovarian cysts following treatment with GnRH analog (fertirelin acetate)

Effects of PGF2(alpha) analog (ONO-1052) on cows with luteinized cysts following treatment with GnRH analog (fertirelin) in inducing estrus and shortening an interval from treatment to conception were investigated in a field trial. Seventy-five cows with follicular cysts diagnosed by rectal palpation were treated intramuscularly (i.m.) with 400 mug fertirelin (an analog of GnRH). Luteinization of follicular cysts were tentatively judged by rectal palpation. Forty-one cows were considered to have luteinized cysts and were either treated i.m. with ONO-1052 (28 cows) or left untreated as controls (13 cows). Thirty-four other cows were considered to have not responded to fertirelin and retreated with 10,000 MU hCG (19 cows) or fertirelin (five cows). This tentative judgment of luteinization of the cysts by rectal palpation after treatment was later confirmed by determining serum progesterone concentration before and 10 to 14 days after treatment. Only in the cows with luteinized cysts which were confirmed by serum progesterone analysis; increased from a pretreatment level below 1.0 ng/ml to a value of 1.0 ng/ml or higher 10 to 14 days after treatment, effects of ONO-1052 combined with fertirelin were investigated. Of the 18 cows with luteinized cysts thus confirmed following fertirelin injection and treated with ONO-1052, 15 (83.3 %) cows came into estrus within 26 +/- 14 (mean +/- SD) days after the first treatment; eight cows within three to five days and four cows within 22 to 28 days, and 14 cows (77.8 %) conceived within 100 days (42 +/- 26 days). On the other hand, the five control cows with luteinized cysts that were not treated with ONO-1052 required significantly longer to exhibit normal estrus (54 +/- 13 days; P<0.05) and to conceive (54 +/- 13 days). These results indicate that ONO-1052 combined with fertirelin may be useful to shorten the interval from treatment to normal estrus and to conception in cows with follicular cysts.     

Comparison of endocrine changes,timing of ovulations,ovarian follicular growth,and efficacy associated with Estradoublesynch and Heatsynch protocols in Murrah buffalo cows (Bubalus bubalis)

Poor estrus expression and the difficulty encountered in predicting the time of ovulation compromise the reproductive efficiency of Murrah buffalo cows. Synchronization of ovulation and timed artificial insemination are able to precisely control the time of ovulation and thus avoid the need for estrus detection. Recently, the Estradoublesynch protocol (administration of a PGF2α injection 2 days before Heatsynch protocol; GnRH 0, PGF2α 7, estradiol benzoate [EB] 8) was developed that precisely synchronized ovulation twice, i.e., after GnRH and EB injections and resulted in satisfactory pregnancy rates in Murrah buffaloes. The present study was conducted on 104 cycling and 31 anestrus buffaloes to compare (1) the endocrine changes, timing of ovulations, ovarian follicular growth, and efficacy of Estradoublesynch and Heatsynch protocols in cycling and (2) the efficacy of Estradoublesynch and Heatsynch protocols for the improvement of fertility in cycling and anestrus Murrah buffalo cows. Ovulation was confirmed after all GnRH and EB treatments by ultrasonographic examination at 2-hour intervals. Plasma progesterone and total estrogen concentrations were determined in blood samples collected at daily intervals, beginning 2 days before the onset of protocols until the day of second ovulation detection. Ovulatory follicle size was measured by ultrasonography at six time points (first PGF2α administration of Estradoublesynch protocol every 2 days before the onset of Heatsynch protocol, GnRH administration of both protocols, 2 hours before ovulation detection after GnRH administration of both protocols, second PGF2α injection of Estradoublesynch protocol, PGF2α injection of Heatsynch protocol, EB injection of both protocols and, 2 hours before ovulation detection after EB administration of both protocols). Plasma LH, total estrogen, and progesterone concentrations were determined in blood samples collected at 30-minute intervals for 8 hours, beginning GnRH and EB injections, and thereafter at 2-hour intervals until 2 hours after the detection of ovulation. The first ovulatory rate was significantly higher (P < 0.05) in the Estradoublesynch protocol (84.6%) than that in the Heatsynch protocol (36.4%). The first LH peak concentration (74.6 ± 10.4 ng/mL) in the Estradoublesynch protocol was significantly higher (P < 0.05) than that of the Heatsynch protocol (55.3 ± 7.4 ng/mL). In Estradoublesynch protocol, the total estrogen concentration gradually increased from the day of GnRH administration coinciding with LH peak, and then gradually declined to the basal level until the time of ovulation detection. However, in Heatsynch protocol, the gradual increase in total estrogen concentration after GnRH administration was observed only in those buffalo cows, which responded to treatment with ovulation. In both Estradoublesynch and Heatsynch protocols, ovulatory follicle size increased by treatment with GnRH and EB until the detection of ovulation. The pregnancy rate after the Estradoublesynch protocol (60.0%) was significantly higher (P < 0.05) than that achieved after the Heatsynch protocol (32.5%). Satisfactory success rate using the Estradoublesynch protocol was attributed to the higher release of LH after treatment with GnRH, leading to ovulation in most of the animals and hence creating the optimum follicular size at EB injection for ovulation and pregnancy to occur.     

Diagnosis of luteal and follicular ovarian cysts in dairy cows by sector scan ultrasonography

Sixty-seven ultrasonograms of ovarian cysts (cysts) from 35 cows were used to evaluate sector scan ultrasonography as a means for differentiating luteal cysts from follicular cysts. Initial diagnosis of cysts was made by ovarian palpation per rectum during weekly herd visits. The ovaries of each cow were then examined by ultrasonography. Ultrasonograms of cysts > 25 mm in diameter were diagnosed as either luteinized or follicular cysts and were recorded on video tape for evaluation by a second clinician. Serum progesterone concentrations at the time of examination were determined by radioimmunoassay and were used to classify luteal (> 0.5 ng/ml) or follicular (相似文献   

Ovarian follicular growth suppression by long-term treatment with a GnRH agonist and impact on small follicle number,oocyte yield,and in vitro embryo production in Zebu beef cows

The aim of the present study was to evaluate small follicle number, oocyte yield, and in vitro embryo production (IVEP) in Zebu beef cows treated long term with a GnRH agonist to suppress ovarian follicular growth. Nelore (Bos indicus) cows (n = 20) showing regular estrous cycles were randomly assigned to one of two groups: control (n = 10, placebo ear implant without a GnRH agonist); GnRH agonist (n = 10, GnRH agonist ear implant containing 9.4-mg deslorelin). All cows underwent an ovum pick-up (OPU) session 14 days (Day 14) before the start of treatments (Day 0) followed by seven OPU–IVEP procedures at 30-day intervals (Days 0, 30, 60, 90, 120, 150, and 180). Semen from a single batch of a previously tested bull was used for all the IVEP. Cows treated with agonist reported a decrease over time in the proportion of animals with a (CL; P ≤ 0.05) and large follicles (>10 mm, P ≤ 0.05). These cows had a lesser number of medium + large follicles (>5 mm; 1.74 ± 0.5 vs. 4.13 ± 0.5; P ≤ 0.05), greater number of small follicles (2–5 mm; 44.3 ± 2.8 vs. 30.8 ± 1.8; P ≤ 0.05), greater yield of cumulus-oocyte complexes (COCs; 21.0 ± 2.3 vs. 15.6 ± 1.9; P ≤ 0.05), greater proportion of COCs cultured (79.2 vs. 73.9%; P ≤ 0.05), COCs cleaved (10.6 ± 1.5 vs. 6.8 ± 1.1, P ≤ 0.05), and cleaved rate (52.8 vs. 44.3%; P ≤ 0.05) compared with control cows. The number (3.4 ± 0.7 vs. 3.0 ± 0.6; P > 0.05) and proportion (16.5 vs. 19.1%; P > 0.05) of blastocysts produced were similar between agonist and control cows, respectively. The study has shown that Zebu beef cows treated long term with a GnRH agonist had follicular growth restricted to small follicles. This did not compromise the ability of oocytes to undergo IVF and embryonic development.