Characterization of ovarian follicular dynamics in dromedary camels (Camelus dromedarius)

Ovarian follicular dynamics was monitored by transrectal ultrasonography, for a period of 60 to 90 days, and its correlation with plasma estradiol-17β (E2) and progesterone (P4) were studied in seventeen, multiparous, non-lactating, 12 to 20-year-old dromedary camels. The average number of follicles recruited (12.77 ± 0.93) in each wave between animals varied (P < 0.001). The number of follicles recruited during different follicular waves was highly repeatable (0.95) within individual animals. The growth and mature phase periods of the dominant follicle (DF) were 6.10 ± 0.15 and 10.20 ± 0.47 days, respectively with a linear growth rate of 1.17 ± 0.02 mm/day between Day 0 and 10 of the follicular wave. There was an inverse relationship between the diameter of the largest DF and number of follicles (r = −0.95, P < 0.001). The DF development did not regularly alternate between the ovaries and the incidence of codominance was 45%. The mean maximum diameter of DF during its mature phase was 27.30 ± 0.78 mm and oversized follicle was 38.43 ± 1.41 mm. In 73.3% waves, the DF continued its growth for a period of 10.64 ± 1.53 days even after losing its dominance and developed into oversized follicle. The duration of the regression phase of DF and oversized follicle were 24.71 ± 3.79 and 18.50 ± 2.23 days. The mean duration of a complete follicular wave was 47.11 ± 2.94 days with an interwave interval (IWI) of 16.36 ± 0.37 days. The IWI within an individual was repeatable (0.88) and between the animals was variable (P < 0.001). Plasma E2 concentration profiles showed a wave like pattern. The peak plasma E2 concentrations were attained approximately 12 days after beginning of the growth phase, when the largest DF grew to a diameter of 18.7 mm. Plasma concentration of P4 was below 1.0 ng/mL in 85% of waves and above 1.0 ng/mL in 15% of the waves for a period of 3 to 6 days in the absence of spontaneous ovulation. It is concluded that ovarian follicular development and plasma E2 concentrations occurs in a wave like pattern in dromedary camels and the IWI and follicle numbers recruited per wave are variable between the animals and repeatable within an individual animal.     

Effect of progesterone from induced corpus luteum on the characteristics of a dominant follicle in dromedary camels (Camelus dromedarius)

The present study was carried out to elucidate the effect of progesterone (P4) from the induced corpus luteum (CL) on the characteristics of the dominant follicle (DF) in dromedary camels (Camelus dromedarius). Ovarian follicular and induced CL dynamics were monitored by transrectal ultrasonography in eight camels during the peak breeding season. The characteristics of the DF were monitored daily from the day of emergence into a wave, until it appeared to lose its dominance and the DF of a subsequent wave grew to a diameter of 13-17 mm. At this stage ovulation was induced by hCG and the DF was monitored every 8 h for 48 h. After ovulation, CL dynamics and follicular development (emergence of a new wave, growth and mature phase of the selected DF) were monitored daily. Blood samples were collected during each ultrasound examination to study the P4 profile in these animals. The CL developed to a maximum size (22.55 ± 3.24 mm) with a peak concentration of P4 (4.60 ± 2.57 ng/ml) 7 days after ovulation. The size of the CL was positively correlated with the P4 concentration (r = 0.612) during the different stages of the CL dynamics. The presence of CL did not affect the linear growth rate, duration of growth and mature phases of the DF. The development of the DF to its maximum size during its mature phase and inter-wave interval were not affected by the P4 secreted by the induced CL. In conclusion, there is no evidence from this study to suggest that P4 from induced CL altered the characteristics of a DF in dromedary camels.     

Synchronisation of ovarian follicular waves in the dromedary camel (Camelus dromedarius)

This study was designed to compare the efficacy of various treatments intended to synchronise follicular wave cycles in dromedary camels by removing the existing follicle of unknown size and replacing it with a follicle capable of ovulating at a known time. Camels were randomly assigned to one of five groups and treated with either (1) 5mg oestradiol benzoate (i.m.) and 100mg progesterone (i.m.; E/P, n=15), (2) 20 icrog GnRH analogue, buserelin (i.m.; GnRH, n=15), (3) 20 microg buserelin (i.m.) on Day 0 (T=0) and 500 microg prostaglandin on Day T+7 (GnRH/PG n=15), (4) transvaginal ultrasound-guided follicle ablation of all follicles > or =0.5 cm (ABL, n=15) or (5) 5 ml saline (i.m; Controls n=15). All camels were subsequently injected with 20 microg buserelin 14 days after the first treatment was given. The ovarian response was monitored daily by transrectal ultrasonography and the intervals from treatment to follicular wave emergence and also the day on which the new dominant follicle reached 1.3 cm was recorded. Amongst the treatment groups the mean interval from treatment to new follicle wave emergence and treatment to time taken for the new dominant follicle to reach 1.3 cm in diameter was shortest in the ABL group (2.3+/-0.5 days and 8.8+/-1.1 days respectively, P=0.044) and longest in the E/P group (6.4+/-0.8 days and 12.2+/-1.0 days respectively, P<0.001) whereas the GnRH and GnRH/PG groups were intermediate (3.0+/-0.5 days and 11.1+/-0.8 days GnRH; and 4.5+/-0.5 days and 10.7+/-0.7 days GnRH/PG). A total of 11/15 camels in both the GnRH and GnRH/PG groups had dominant follicles between 1.3 and 1.9 cm 14 days post treatment, of which 21 of the 22 follicles ovulated after GnRH injection on T+14. The ABL, E/P and control groups however, showed greater variability in follicle size with less camels having dominant follicles between 1.3 and 1.9 cm than the GnRH and GnRH/PG groups and more in the > or =2.0 cm or follicle regressing groups, therefore fewer of these camels ovulated (ABL n=7; E/P n=9; Control n=6) after GnRH injection on Day T+14. In conclusion, two GnRH injections 14 days apart or two GnRH injections 14 days apart and PG on Day 7 after the first GnRH were the most effective methods to synchronise ovulation rate in dromedary camels at a fixed time interval of 14 days after treatment.     

Restoring ovulation in beef donor cows with ovarian cysts by progesterone-releasing intravaginal silastic devices.

The objective of this study was to determine the efficacy of a progesterone-releasing intravaginal silastic device (Controlled Internal Drug Release: CIDR) for inducing ovulation in beef cows with persistent ovarian cysts. Fifteen cows with cysts and abnormal cycles for over 40 days were randomly assigned to receive either a single CIDR (CIDR group, n=9), or a CIDR containing no progesterone (blank CIDR) (BLANK group, n=6) for about 14 days. Determination of plasma progesterone levels at the beginning of CIDR treatment indicated 4 of 6 BLANK cows with non-luteinized cysts and 5 of 9 CIDR cows with non-luteinized cysts. In 5 of 6 BLANK cows, one follicular wave appeared and newly emerged dominant follicles increased in size up to 20 mm in diameter and persisted during the experiment, while one cow experienced estrus with spontaneous ovulation. In contrast, during CIDR treatment, 2 or 3 waves, in which dominant follicles were from 7 to 15 mm in diameter, appeared approximately at 7-day intervals. Within 3 days after CIDR removal, estrous behavior was detected followed by ovulation of the dominant follicle in the last wave. All CIDR cows resumed normal cyclicity with 2 follicular waves for over 2 months. Insertion of a CIDR caused a rapid increase of about 2 ng/mL in plasma progesterone. The levels were greater than 1.3 ng/mL until removal of a CIDR, then dropped under 0.3 ng/mL. Concentrations of plasma estradiol in BLANK cows increased during growth of the cystic follicles, with high levels greater than 10 pg/mL for over 10 days. In 4 of 5 cows with non-luteinized cysts, with high plasma estradiol on the day of CIDR insertion, CIDR treatment resulted in rapid decline of estradiol levels. During placement of the CIDR, estradiol levels showed no increase in the growth phase of a newly appeared dominant follicle. After CIDR removal, however, estradiol significantly increased associated with the growth of ovulatory follicles in all 9 cows. A transient increase in plasma FSH levels preceded detection of each follicular or cyst wave in both BLANK and CIDR cows. Pulse frequency and mean concentration of LH in cows with non-luteinized cysts showed values corresponding to those in normal follicular phase. However, throughout CIDR treatment, these parameters reduced to levels found in the normal luteal phase. In cows with luteinized cysts, parameters of LH secretion were as low as in the normal luteal phase before and during CIDR treatment, then increased significantly after CIDR removal. Present results indicate that treatment with CIDR proved effective in restoring ovulation and reestablishing normal cyclicity in beef donor cows with cysts persistent for a long period. The CIDR reduced and maintained LH secretion at normal luteal levels, thereby, inducing atresia of estrogen-active cysts and preventing formation of cysts from the newly emerged follicles.     

Comparison of the effect of estradiol benzoate plus progesterone and GnRH on the follicular wave emergence and subsequent follicular development in CIDR-treated, lactating dairy cows with follicular cysts

This study examined the effect of estradiol benzoate (EB) plus progesterone (P4) as compared with GnRH on follicular wave emergence and follicular development, and synchrony of ovulation and pregnancy rates following a second injection of GnRH in a controlled internal drug release (CIDR)-based timed AI (TAI) protocol in lactating dairy cows with follicular cysts. Lactating dairy cows diagnosed with follicular cysts received a CIDR device, with an injection of 2mg EB plus 50mg P4 (EB+P4 group) or with an injection of 100 microg GnRH (GnRH group) at the beginning of the experiment (day 0). Thereafter, all received PGF(2alpha) at the time of CIDR removal on day 7, GnRH on day 9, and TAI 16 h later. Follicular wave emergence occurred within 7 days in 12/15 EB plus P4-treated and 14/15 GnRH-treated cows (P>0.05). The interval to wave emergence was longer in the EB+P4 group (4.8+/-0.4 days) than in the GnRH group (2.0+/-0.2 days). The mean diameters of preovulatory follicles and the proportion of cows with preovulatory follicles greater than 12 mm on day 9 did not differ between groups (P>0.05). The proportion of cows with synchronized ovulations by 40 h after the GnRH injection on day 11 and pregnancy rates to TAI did not differ between the EB+P4 (13/15 and 36.7%) and the GnRH (14/15 and 53.3%) groups, respectively. Results suggest that a single treatment with EB plus P4 as compared with GnRH simultaneously with CIDR insertion in lactating dairy cows with follicular cysts will result in relatively asynchronous emergence of a new follicular wave, but subsequently similar sizes of preovulatory follicles and synchronous ovulation, resulting in similar pregnancy rates to TAI.     

Effectiveness of melatonin and controlled internal drug release device treatment on reproductive performance of buffalo heifers during out-of-breeding season under tropical conditions

Sixteen Murrah buffalo heifers, divided into control and treatment groups of eight animals each, were used to study the effect of melatonin and controlled internal drug release (CIDR) device treatment on the resumption of ovarian activity during out-of-breeding season (summer solstice). Treated group was implanted with melatonin (18 mg of melatonin per 50 kg of body weight) for 45 days and then heifers of both groups received CIDR for 9 days. All heifers received intramuscular 500 IU eCG on the day before CIDR removal and 10 μg GnRH on the day after CIDR withdrawal. All animals were subjected to estrus detection daily. Blood sampling in conjunction with transrectal ultrasonography were performed twice weekly to determine serum concentrations of melatonin, progesterone, LH, and antioxidant enzyme activities, as well as to monitor the ovarian follicular activity. Melatonin treatment resulted in an increase (P < 0.01) in serum melatonin and a decrease (P < 0.01) in serum progesterone and LH. In addition, melatonin had no significant effect on the frequency of LH pulses. Furthermore, melatonin treatment increased (P < 0.01) the diameter of the largest follicle and the number of large follicles between Days 0 and 35 of melatonin treatment. However, melatonin exhibited superior ability to maintain CL at 21 days after artificial insemenation (AI) and increased the percentage of conception to threefold higher than control. In conclusion, melatonin implantation successfully improved the diameter of largest follicles and the ability to maintain CL at 21 days after AI in buffalo heifers during out-of-breeding season under tropical conditions.     

Phimosis in male dromedary camels: Clinical findings and changes in the hemogram,nitric oxide metabolites,and testosterone concentrations

The objectives of this study were to elucidate the clinical findings in male dromedary camels with phimosis (PHI, n = 43) and to investigate the association of this syndrome with the hemogram, nitric oxide metabolites (NOMs), and testosterone concentrations. History and signalment were obtained, and a breeding soundness examination was performed. The penis was exteriorized after administration of a pudendal nerve block. Abnormal masses obtained from the prepuce and penis were prepared for histopathology. Blood samples for hemogram assessment were taken from the diseased animals and from 10 healthy control males. Total nitrates/nitrites were determined in sera using the Griess assay. Testosterone was estimated in sera using ELISA. Phimosis associated with detectable pathologic lesions, mainly including ulcerative posthitis and lacerated glans penis, was present in 34 (79.1%) of the 43 cases (PHI-P), whereas the remaining nine (20.9%) of the 43 cases had no noticeable lesions (PHI-N). The PHI-P group showed higher leukocyte counts (P = 0.001), especially neutrophils (P = 0.0001), and greater NOM concentrations (P = 0.002) than the PHI-N and control groups. However, testosterone concentrations did not differ among groups. In conclusion, PHI in the male dromedary camels was mainly associated with ulcerative posthitis and laceration of the glans penis. The presence of pathologic lesions in cases with PHI was associated with leukocytosis, neutrophilia, and high NOM concentrations.     

Hormone concentrations before and after semen-induced ovulation in the bactrian camel (Camelus bactrianus)

During the follicular phase of bactrian camels, basal concentrations of LH were 2.7 +/- 1.2 ng/ml. By 4 h after insemination peak values of 6.9 +/- 1.0 ng/ml occurred. In addition, a smaller LH peak (5.4 +/- 2.5 ng/ml) appeared 1 day before regression of the follicle began in unmated camels. During the follicular phase peripheral plasma progesterone values were low (0.36 +/- 0.28 ng/ml), but values increased to reach 1.73 +/- 0.74 ng/ml at 3 days and 2.4 +/- 0.86 ng/ml at 7 days after ovulation. Plasma oestradiol-17 beta concentrations were 26.8 +/- 9.0 pg/ml during the follicular phase and 30.8 +/- 5.1 pg/ml when the follicle was maximum size. Values fell after ovulation but rose to 29.8 +/- 6.5 pg/ml 3 days later.     

Effects of repeated transvaginal ultrasound–guided aspirations performed in anestrous and cyclic mares on P4 and E2 plasma levels and luteal function

The aim of the present study was to verify how repeated ovum pick-up (OPU), performed in anestrous and cyclic mares, affect ovarian activity, measured by progesterone (P4) and 17ß-estradiol (E2) plasma levels. Ovum pick-up of all visible follicles was performed every 9 to 12 days, and four sessions were carried out during anestrous (A) and breeding season (BS). The number of aspirated follicles per mare at each session was not significantly different between the two periods (BS: 6.1 ± 2.4; A: 7.5 ± 4.4; P > 0.05), but the mean follicular diameter was significantly higher during BS (16.0 ± 7.1 vs. 10.2 ± 5.1 mm; P < 0.05); during A the number of aspirated follicles less than 15 mm in diameter resulted significantly higher than that registered in BS (5.1 ± 2.7 vs. 3.0 ± 1.8; P < 0.05). The total mean value of P4 was higher in BS than in A (6.3 ± 4.4 vs. 0.3 ± 1.8 ng/mL; P < 0.05), whereas the total mean level of E2 was not different between the two periods (3.8 ± 3.4 vs. 2.5 ± 2.7 pg/mL; P > 0.05). Estradiol plasma values resulted positively correlated, in A and BS, with diameter of follicles detected on the ovaries (R = 0.345 and R = 0.331, respectively), whereas a negative correlation was observed between P4 and follicular diameter in BS (R = −0.162). Both E2 and P4 presented a high individual variability during BS; in particular, in three of seven mares, P4 trend was compatible with a normal estrous cycle, and the interval between two consecutive peaks was 21 days. In two of seven mares, with CL at first OPU, P4 concentrations remained more than 3 ng/mL throughout the entire treatment period. Finally, in two of seven animals, P4 levels initially showed a similar pattern to that of a normal estrous cycle, then, after the second aspiration, they remained consistently higher than 3 ng/mL. When the procedure was carried out in cyclic animals, the influence of this technique on ovarian activity seemed to be related to individual variability although, according to progesterone values, structures observed on the ovaries after aspirations presented luteal function. Furthermore, the resumption of normal ovarian activity, after repeated OPU sessions, occurred in a period not much longer than the duration of a normal estrous cycle (25.4 ± 5.2 days). Data recorded during nonbreeding period showed that repeated OPU in anestrous mares do not affect ovarian activity and do not anticipate the resumption of ovarian cyclicity. However, based on the number of aspirated follicles in anestrous and cyclic mares, both types of subjects could be considered as oocyte donors.     

Evaluation of an ovarian synchronization scheme for fixed-time artificial insemination in wapiti

The ovarian response to an empirically derived treatment protocol used commercially for fixed-time insemination in wapiti (Cervus elaphus) was evaluated by transrectal ultrasonography in hinds during transition into the ovulatory season. On September 29, hinds (n=7) were given an intravaginal progesterone-releasing device (CIDR-B, 1.9 g of progesterone) or left untreated (controls, n=9). Fourteen days later, hinds in the treated group were given 200 IU eCG and the CIDR was removed. Hinds in the control group ovulated randomly over a 15 day period. In the treated group, five hinds ovulated 3 days after eCG treatment, one ovulated 7 days after treatment, and one failed to ovulate by November 1. All extant dominant follicles ceased growth and/or began to regress within 2 days of CIDR placement. Two waves of follicular development were detected between CIDR insertion and removal; the first emerged 5.1+/-0.5 days after CIDR insertion and the second at 11.0+/-0.7 days. Serum progesterone concentration was 0.6+/-0.5 ng/mL (range 1.0-0.3 ng/mL) before CIDR placement, remained above 6 ng/mL during CIDR placement, and fell to 0.8+/-0.9 ng/mL after CIDR removal. In the control group, maximal luteal-phase progesterone concentration was lower (1.1+/-0.1 ng/mL; P<0.05) and emergence of the first follicular wave was more variable (P=0.05) than in the treated group. The protocol to synchronize ovulation was effective in 5/7 (71%) hinds, and 4/7 (57%) became pregnant and calved. The pregnancy rate (6/9) and calving rate (5/9) was similar in the control group. In conclusion, synchronization with CIDR-B was effective; however, the protocol may be improved by shortening the interval of CIDR placement to < or = 7 days and by reducing the circulating concentrations of progesterone to physiologic concentrations (< 4 ng/mL).     

Fertility after ovarian follicular wave synchronization and fixed-time natural mating compared to random natural mating in dromedary camels (Camelus dromedarius)

The objective of the study was to compare the efficiency of two ovarian follicular wave synchronization protocols coupled with fixed-time natural mating with that of random mating in dromedary camels. Dromedaries were assigned randomly to one of the three treatment groups. Group 1 animals (RM; n = 46) were mated randomly. Group 2 camels (1×GnRH-FTM; n = 46) were given a GnRH analog (Buserelin, 20 μg/animal, i.v.; Receptal, Intervet, Holland) at random, then were mated 14 days later. In Group 3 animals (2×GnRH-FTM; n = 41), random GnRH analog was followed by repeated GnRH injection 14 days later and fixed-time natural mating on Day 28. Transrectal examination and ultrasonography were performed at weekly intervals to evaluate ovarian follicular status, diagnose ovulation and pregnancy. Blood samples were collected for progesterone determination by ELISA to confirm ovulation and pregnancy. All female dromedaries were assigned randomly to one of thirteen fertile bulls and were bred once on Days 1, 14 and 28 in Groups 1-3, respectively. Ovarian follicular status and ovulation rate was similar among groups at the start of the study. Seventy-five of the 133 dromedaries (56.4%) ovulated after random natural mating or random GnRH treatment. Mean length of mating was 386 ± 17.8 (±SEM) seconds. There was no significant difference in mating time among groups and in pregnancy rate among dromedary bulls. In Group 3 (2×GnRH-FTM), ovarian follicular status before mating (P < 0.05), ovulation rate (n = 37, 90.2%, P < 0.001) and pregnancy rate at 21 and 60 days (PR 21 days n = 22, 53.7% and PR 60 days n = 19, 46.3%, P < 0.05) were greater compared to random natural mating (Group 1: OR n = 25, 54.3%, PR 21 days n = 13, 28.3% and PR 60 days n = 12, 26.1%). In Group 2 dromedaries (1×GnRH-FTM), treatment tended to improve follicular status before mating, ovulation rate (n = 34, 73.9%) and pregnancy rate at 21 and 60 days (PR 21 days n = 21, 45.7% and PR 60 days n = 16, 34.8%), but the effect was not significant compared to random natural mating. In conclusion, this is the first study demonstrating that favorable pregnancy rate can be achieved following ovarian follicular wave synchronization with repeated GnRH analog and fixed-time natural mating at 14 days intervals in dromedary camels.     

Effects of estradiol cypionate (ECP) on ovarian follicular dynamics,synchrony of ovulation,and fertility in CIDR-based,fixed-time AI programs in beef heifers

Estradiol cypionate (ECP) was used in beef heifers receiving a controlled internal drug release (CIDR; insertion = Day 0) device for fixed-time AI (FTAI) in four experiments. In Experiment 1, heifers (n = 24) received 1mg ECP or 1mg ECP plus 50mg commercial progesterone (CP) preparation i.m. on Day 0. Eight or 9 days later, CIDR were removed, PGF was administered and heifers were allocated to receive 0.5mg ECP i.m. concurrently (ECP0) or 24h later (ECP24). There was no effect of treatment (P = 0.6) on mean (+/-S.E.M.) day of follicular wave emergence (3.9+/-0.4 days). Interval from CIDR removal to ovulation was affected (P<0.05) only by duration of CIDR treatment (88.3+/-3.8h versus 76.4+/-4.1h; 8 days versus 9 days, respectively). In Experiment 2, 58 heifers received 100mg progesterone and either 5mg estradiol-17beta or 1mg ECP i.m. (E-17beta and ECP groups, respectively) on Day 0. Seven (E-17beta group) or 9 days (ECP group) later, CIDR were removed, PGF was administered and heifers received ECP (as in Experiment 1) or 1mg EB 24h after CIDR removal, with FTAI 58-60h after CIDR removal. Follicular wave emergence was later (P<0.02) and more variable (P<0.002) in heifers given ECP than in those given E-17beta (4.1+/-0.4 days versus 3.3+/-0.1 days), but pregnancy rate was unaffected (overall, 69%; P = 0.2). In Experiment 3, 30 heifers received a CIDR device and 5mg E-17beta, with or without 100mg progesterone (P) i.m. on Day 0. On Day 7, CIDR were removed and heifers received ECP as described in Experiment 1 or no estradiol (Control). Intervals from CIDR removal to ovulation were shorter (P<0.05) in ECP0 (81.6+/-5.0h) and ECP24 (86.4+/-3.5h) groups than in the Control group (98.4+/-5.6h). In Experiment 4, heifers (n = 300) received a CIDR device, E-17beta, P, and PGF (as in Experiment 3) and after CIDR removal were allocated to three groups (as in Experiment 2), with FTAI 54-56h (ECP0) or 56-58h (ECP24 and EB24) after CIDR removal. Pregnancy rate did not differ among groups (overall, 63.6%, P = 0.96). In summary, although 1mg ECP (with or without progesterone) was less efficacious than 5mg E-17beta plus 100mg progesterone for synchronizing follicular wave emergence, 0.5mg ECP (at CIDR removal or 24h later) induced a synchronous ovulation with an acceptable pregnancy rate to fixed-time AI.     

Effect of season and gonadotropins on the superovulatory response in camel (Camelus dromedarius)

The purpose of the present investigation was to study the extent to which season and the gonadotropin preparation interferes with the superovulatory response in the dromedary. Adult camels were treated for superovulation during the breeding (November to April) and non-breeding season (May to October). Animals were synchronized by daily i.m. injections of progesterone (125 mg/animal/day, Jurox, UK) for 10 to 14 days. Superovulation was induced by 400mg pFSH alone (Follitropin V, Vetrepharm, Canada) administered in eight descending doses at 12h intervals or a combination of PMSG (2000IU, Folligon, Intervet, The Netherlands), injected with last injection of progesterone and 400mg pFSH in eight descending doses. The follicular development was daily assessed by ultrasonography of the ovaries. The donors were classified as per their response to the superovulatory treatment into very good (>10 follicles), good (5-10 follicle), poor (2-4 follicles) or no response (1 or no follicle) on each ovary. Ovulation was induced by injecting 3000 IU hCG (Chorulon, Intervet) at the time of first mating. The donors were mated twice at an interval of 12h when all or most of the follicles reached to a size of about 1.0-1.7 cm. Camels were flushed non-surgically on Day 6 or 7 after the ovulation. The proportion of camels showing very good response during the breeding as well as non-breeding season was higher (P<0.05) when a combination of pFSH and eCG was used compared with pFSH only. There was no difference (P>0.05) in the proportion of donors flushed successfully (embryos recovered) when treated either with a combination of pFSH and eCG or pFSH alone during the breeding and non-breeding season. The rate of recovery of ova/embryos and proportion of transferable embryos was higher (P<0.05) when donors were treated with pFSH+eCG compared with pFSH only during the breeding as well as non-breeding season. The results may indicate that ova/embryo recovery rate of the dromedary is influenced by the gonadotropin preparation but is not appreciably affected by the season.     

Estrogen concentrations in milk at estrus and ovulation in dairy cows

The aim of the present study was two-fold. First, to characterize the secretory profiles of oestradiol-17beta and progesterone in relation to the structural changes observed by ultrasonography during follicular dynamics in non-ovulating llamas. Second, to evaluate the effect of exogenous progesterone on follicular activity, in terms of follicle development and hormone production. In experiment one, six adult non-pregnant, non-lactating llamas were examined daily by rectal palpation and transrectal ultrasonography during 70 days. On day 54, intravaginal devices containing 0.33 g of progesterone (CIDR) were inserted and left in the vagina during 16 days. The mean duration of a follicular wave was 22.6+/-2.5 days. The follicular growth phase (follicles growing from 3mm to maximum size) averaged 9.2+/-2.8 days, the mature phase (follicles around maximum size) 5.2+/-1.4 days and regression phase (follicles with decreasing size) 8.2+/-2.2 days. Oestradiol-17beta plasma concentrations exhibited a similar wave pattern (P<0.05). In addition, oestradiol-17beta peak plasma concentrations (46.9+/-3.3 pmoll(-1)) were attained approximately 12 days after the beginning of the growing phase in connection with maximum follicle size (11.8+/-1.6mm). After CIDR insertion, a rapid increase in plasma progesterone concentrations was observed, with peak concentrations attained on day 1 after insertion. Thereafter, concentrations decreased gradually. Mean follicle size steadily decreased from the day of CIDR insertion to day 11 post-insertion (10.3+/-1.6 and 3.3+/-0.8mm, respectively). In order to investigate the effect of follicle size at CIDR insertion on the outcome of progesterone treatment, experiment two was designed. Sixteen adult non-pregnant and non-lactating llamas were divided into four groups according to follicle development at the time of CIDR insertion (group I: follicles < or =6 mm; group II: follicles between 6 and 9 mm; group III: follicles between 10 and 14 mm and group IV, regressing follicles). In groups II, III and IV, a significant decrease in follicle size was observed after the insertion of the CIDR device. In group I, no further development of dominant follicles was observed until the device was withdrawn. In all cases, the smallest diameter was registered between days 5 and 7 after the beginning of treatment. In conclusion, a detailed characterization of follicular waves using ultrasound and hormone determinations simultaneously in non-ovulating llamas and after the insertion of progesterone releasing devices, is presented.     

Effects of exogenous progesterone and cloprostenol on ovarian follicular development and first ovulation in prepubertal heifers

The objective of this study was to determine the effects of progesterone and cloprostenol (a PGF_2α analogue) on ovarian follicular development and ovulation in prepubertal heifers. In Experiment 1, crossbred Hereford heifers (Bos taurus; 10 to 12 mo old, 255 to 320 kg) were assigned randomly to three groups and given (1) an intravaginal progesterone-releasing insert (CIDR; P group, n = 13); (2) a CIDR plus 500 μg cloprostenol im (PGF_2α analogue) at CIDR removal (PPG group, n = 11); or (3) no treatment (control group, n = 14). The CIDR inserts were removed 5 d after follicular wave emergence. Progesterone-treated heifers (P and PPG groups) had a larger dominant follicle than that of the control group (P = 0.01). The percentage ovulating was highest in the PPG group (8 of 11, 73%), intermediate in the P group (4 of 13, 31%), and lowest in the control group (1 of 14, 7%; P < 0.02). In Experiment 2, 16 heifers (14 to 16 mo old, 300 to 330 kg) were designated to have follicular wave emergence synchronized with either a CIDR and 1 mg estradiol benzoate im (EP group, n = 8) on Day 0 (beginning of experiment) or by transvaginal ultrasound-guided ablation of all follicles ≥5 mm on Day 3 (FA group, n = 8). On Day 7, CIDRs were removed in the EP group, and all heifers received 500 μg cloprostenol im. Ovulation was detected in 6 of 8 heifers (75%) in both groups. In summary, the use of PGF_2α with or without exogenous progesterone treatment increased the percentage ovulating in heifers close to spontaneous puberty.     

Behavioral indicators to detect ovarian phase in the dromedary she-camel

This pilot study was conducted to test the hypothesis that female camels behave differently in various ovarian phases in the presence of a restrained male camel. The aim was to identify behavioral patterns which could be used as indicators to detect ovulatory phase by visual observation in the presence of a restrained virile bull. Twenty-four healthy, nonpregnant, and nonlactating adult females were used. Transrectal ultrasonography was performed for each animal once a week over a 3-week period to determine the phase of the ovarian cycle. Females were considered to be in the ovulatory phase (O) when there was at least one preovulatory follicle (12<Ø<19 mm) protruding from the ovarian surface, and in the nonovulatory phase (NO), when growing follicles, regressing follicles, or corpora lutea were detected. Immediately after examination, each female was freely exposed to a restrained bull for 15 minutes, and her behaviors were filmed. The videos were analyzed through a focal animal-sampling ethogram (states: looking at the male; looking outside; standing close to the male; searching; and lying down; events: interaction with the male; urination; defecation; sound emission; and steps). A score for tail position (tail score: 1 = close to the vulva, 2 = horizontal, 3 = vertical) and for interest in the bull (male time score: from 1 to 5; 1 = <20% of observation period spent near the bull; 5 = more than 80%) were recorded. Ovulatory phase camels showed higher interest in the male than nonovulatory phases: they stood close to the male for longer periods (P = 0.0159), interacted with the male more frequently (P = 0.0004), and tended to lie down in front of him (P = 0.1202). Moreover, ovulatory phase had a significant effect on male time score (P < 0.01), mature follicular ovarian phase being associated with higher scores. Seeking the male has already been proposed as a behavioral indicator of estrus in camels, this has now been confirmed using a standardized ethogram. The present results clarify that camels behave differently in different ovarian phases and that monitoring their behavior in the presence of a restrained bull could help detect their ovulatory phase. This would have profound implications for enhancing fertility in dromedary camels by improving timing of mating or artificial insemination.     

Ovarian response and pregnancy rate following different doses of eCG treatment in Chall ewes

The purpose of the study was to investigate the effects of different doses of equine chorionic gonadotropin (eCG) treatment on follicular development, ovulation and pregnancy rate during the breeding season in fat-tailed Chall ewes. Seventy-two cycling (62.5 ± 2.5 kg), multiparous Iranian Chall ewes were used in the trial. The ewes were randomly allocated to 6 groups (n = 12/group). Estrus was synchronized with the aid of controlled intravaginal drug release (CIDR) devices, inserted for 14 days. At the time of CIDR removal (day 14), the ewes received i.m. either 0 (control group, G0), 450 (G450), 550 (G550), 650 (G650), 750 (G750) or 850 (G850) IU eCG. Vasectomized rams were used to detect estrus in the ewes from 24 h after CIDR removal. Ovarian follicular activity was monitored with the aid of transrectal ultrasonography on the day of CIDR insertion (day 0) and daily from the day of eCG treatment (day 14), until estrus (day 16). During these days, blood samples were collected for the determination of plasma progesterone and estradiol concentrations. Laparoscopic intrauterine inseminations were conducted 54–60 h after CIDR removal. The number of CL's and pregnancy diagnosis was recorded using ultrasonography 7 and 54 days following AI, respectively. Half of ewes in control group and most of the ewes treated with eCG showed signs of estrus within 36 h of CIDR removal. The ewes in groups G750 and G850 recorded the highest number of large follicles at estrus and CL's 7 days later. The pregnancy rate in groups G550 (75.0%) and G650 (75.0%) was higher (P < 0.05) than that in the other groups. The ovarian response and estradiol concentration, as well as pregnancy rate showed that 550 or 650 IU eCG treatment is the most effective doses in improving the pregnancy rate in Iranian Chall ewes.     

Persistence and recovery of regressing 3-mm ovarian follicles in heifers

The persistence and outcome of 3-mm follicles before the emergence of follicular wave 1 were studied every 6 hours in 15 heifers beginning on Day 14 (Day 0 = ovulation). A mean of 9.1 ± 1.3 persistent 3-mm follicles (P3Fs) per heifer was detected with persistence for 3.5 ± 0.1 days. The P3Fs either regressed continuously and remained in the 3-mm range (3.0–3.9 mm) or regressed but with a transient increase in diameter during regression. Some (43%) P3Fs were rescued to become growing follicles in wave 1. The number of follicles that became part of wave 1 was less (P < 0.0001) for follicles that originated from a P3F (4.2 ± 1.0 P3Fs) than for follicles that did not originate from a P3F (11.9 ± 1.6 follicles). The day of rescue of wave 1 follicles from a P3F (Day −1.1 ± 0.6) was earlier (P < 0.001) than for emergence of follicles at 3 mm that did not originate from a P3F (Day −0.5 ± 0.5). A cluster of 5.1 ± 0.6 P3Fs was identified in 10 of 15 heifers by the synchronized peaks of transient diameter increases at the 6-hour interval corresponding to Day −4.0 ± 0.3. Concentrations of FSH oscillated at 12-hour intervals with a peak (P < 0.05) 6 hours before and 6 hours after the beginning of a transient diameter increase during a P3F. Concentration of FSH was greater (P < 0.02) in heifers with a high number (11–18) of P3Fs per heifer (0.27 ± 0.02 ng/mL) than with a low number (2–9) per heifer (0.17 ± 0.008 ng/mL). Results supported the novel hypothesis that 3-mm follicles may persist for two or more days and may be rescued to become growing follicles of wave 1.     

The effect of a progesterone (P4) intravaginal device (CIDR) on resynchronisation of oestrus and embryonic loss in previously timed inseminated dairy heifers

A study was done to evaluate the effect of using progesterone (P4) intravaginal device (CIDR: controlled internal drug-releasing dispenser) to synchronise the return to oestrus of previously timed inseminated (TAI) dairy heifers, and to evaluate embryo survival and pregnancy rate (PR) in the return to oestrus heifers. At the onset of the artificial insemination (AI) breeding period (day -9), heifers were randomly assigned into two groups (treated group CGPG, n = 79) and (control group GPG, n = 83). Every heifer in both groups was injected with gonadotropin-releasing hormone (GnRH) agonist and prostaglandin F2-alpha (PGF2α) as follows: GnRH on day -9; PGF2α on day -2; GnRH and TAI on day 0. Heifers in both groups received TAI within 30 min after the second GnRH injection. Artificial insemination at first breeding was conducted for all heifers during 55 days from day 0. On day 14 after timed insemination, every heifer in the CGPG group received CIDR device for 6 days. Within 3 days after CIDR removal, more heifers in CGPG group showed oestrus within 1.9 days compared to heifers that showed oestrus within 2.9 days in the control. Within 10 days after CIDR removal, more heifers in the CGPG group showed oestrus within 2.4 days compared to heifers that showed oestrus within 6.7 days in the control. PRs on days 30 and 55 were not different between both groups, while PR on day 55 during September were higher (P = 0.032) in CGPG group (58.0%) than GPG group (37.0%). In addition, PR from first to second AI was higher (P = 0.037) for CGPG group (79.8%) than for GPG group (65.1%) but it was similar after that. Pregnancy losses between days 30 and 55 tended to be lower (P = 0.089) for the CGPG group (12.7%) compared to 25.1% for the GPG group. Interval between first and second AI was lower (P = 0.052) for the CGPG group (27.5 ± 1.6 days) compared to 31.6 ± 1.3 days for heifers in the GPG group but no differences were detected for intervals from second to third AI and from third to fourth AI between the two groups. Number of services per pregnancy was not different between CGPG and GPG groups. Results indicate that the CIDR device improved synchronisation to return to oestrus and increased PR to first AI during high temperature months by reducing embryonic losses.     

Preliminary assessment of somatic cell nuclear transfer in the dromedary (Camelus dromedarius)

Somatic cloning may enable the maintenance/expansion of the population of camels with the highest potential for milk production or the best racing performances. However, there have been no reports of embryonic or somatic nuclear transfer in camels. The aim of this study was to produce dromedary embryos by nuclear transfer using in vitro matured oocytes and two somatic cells from two sources (adult fibroblasts or granulosa cells). A total of 58 adult females were superstimulated by a single dose of eCG (3500 IU). Ten days later, their ovaries were collected postmortem. Cumulus–oocytes-complexes (COCs) were aspirated from stimulated follicles and were matured in vitro for 30 h. Fibroblasts (from live adult male) and granulosa cells (from slaughtered adult females) were used as donor karyoplasts and injected into mature enucleated dromedary oocytes.The cleavage rate was significantly higher (P < 0.05) for embryos reconstructed with fibroblasts (59%) versus those with granulosa cells (45%). However, there was no difference between the two groups in the proportion of cloned embryos reaching the blastocyst stage (fibroblasts: 14% vs. granulosa cells: 15%) or those that hatched (fibroblasts: 10% vs. granulosa cells: 12%). The viability of reconstructed dromedary embryos from the two sources of donor cells (fibroblasts; n = 5 vs. granulosa cells; n = 7) was examined by transferring them to synchronized recipients. Two females (fibroblasts: 1/5; 20%, granulosa cells: 1/7; 14%) were confirmed pregnant by ultrasonography at 15 and 25 days following transfer. Later, the pregnancies were followed by pregnancy empirical-symptoms. These two pregnancies were lost between 25 and 60 days following transfer, respectively.In conclusion, the present study shows for the first time that the development of dromedary NT embryos derived from either adult fibroblasts or granulosa cells can occur in vitro and the transfer of these cloned embryos to recipients can result in pregnancies.