Effect of exogenous insulin administration on ovarian function, embryo/fetal development during pregnancy in goats

The effect of insulin was investigated on ovarian follicle population, ovulation rate, hormonal profiles and embryo/fetal development during pregnancy using transrectal ultrasonography in goats. Twelve goats synchronized in estrus were selected for the experiment. They were divided into two groups, viz. (untreated control, n=6) and (insulin treated, n=6). In treated group long acting bovine insulin was administered @ 0.2IU/kg body weight subcutaneously for three consecutive days, i.e. days 7-9 of estrous cycle. Thereafter, weekly single injection of insulin was continued for rest of the experiment. However, in control group only normal saline was injected as placebo. Breeding was allowed by natural service in both the groups. The does were subjected to B-mode transrectal ultrasound scanning of ovary and uterus weekly up to 120 and 98 days of gestation, respectively. Blood samples were collected weekly up to 135 days of gestation for the estimation of estradiol 17beta and progesterone (P4). The result revealed no difference in mean number of total follicles between the control and insulin treated groups. The diameter of medium follicle did not differ where as diameter of large follicle was comparatively higher in treated than control goats. The average number of corpus luteum (CL) was higher in insulin treated group as compared to control (1.66 vs. 1.16). However, the number as well as mean diameter of CL did not differ significantly between treated and control group. Serum concentrations of estradiol 17beta and progesterone were significantly (P<0.01) higher in treated than control goats. Embryonic vesicle was detected by day 21 in both the groups, however, its diameter did not differ significantly (0.73 and 0.72cm) between the groups. The twinning percentage was higher (50 vs. 16%) in insulin treated than the control goats. Placentome diameter was also higher (P>0.05) in treated animals. The results demonstrated beneficial effect of exogenous administration of insulin on ovarian function and twinning percentage in goats.     

Effect of intrauterine device on ovarian function in goats

The effect of a polyethylene intrauterine device on oestrous cycle length and ovulation has been studied in goats. Insertion of intrauterine device in nine goats shortened the oestrous cycle length to an average of 10.44 days as compared to the average oestrous cycle length of 17.55 days in nine sham-operated control animals. The oestrous cycle length was reduced irrespective of the fact whether the IUD was ipsilateral or contralateral to the corpus luteum, indicating a systemic effect rather than local effect of the IUD, as seen in other animals such as the sheep, cow and guinea pig. There was no effect on ovulation, which occurred normally despite the presence of the IUD.     

Effect of service on estrus duration in dairy goats

The objective of this research was to determine the effect of sterile service on estrus duration in multiparous and nulliparous dairy goats. Twenty Nubian goats (10 multiparous and 10 nulliparous) were randomly assigned to of 4 treatment groups (n = 5 animals per group). Group MNS, multiparous without service; Group MS, multiparous with service; Group NNS, nulliparous without service and Group NS, nulliparous with service. Estrus was synchronized by utilization of fluorogestone acetate intravaginal pessaries (40 mg.) over a 12-day period plus 250 IU, i.m. of pregnant mare serum gonadotropin (PMSG) at pessary removal. Estrus was detected with the aid of a vasectomized buck for 5 days after pessary removal for 6-hour intervals (0600, 1200, 1800 and 2400 hours). In the groups that were not serviced the teaser was equipped with an apron and was only allowed to mount. In the serviced groups, the teaser was permitted to mount and service each female on 2 occasions during the first 12 hours of estrus. Estrus initiation for Groups NNS, NS, MNS and MS were (mean +/- SD) 61.5 +/- 29.5, 61.2 +/- 35.4, 63.0 +/- 22.2 and 69.6 +/- 32.5 hours, respectively (P>0.05). Estrus duration for the same groups were (mean +/- SD) 42.0 +/- 12.0, 30.0 +/- 6.0, 42.0 +/- 7.3 and 28.8 +/- 10.7 hours, respectively. These results show that estrus duration was shortened by serving (P<0.01), and that there were no differences between multiparous and nulliparous goats with or without serving (P>0.05). It is concluded that estrus duration in goats is shortened by serving and that no differences in duration exist between multiparous and nulliparous.     

Effect of service number on estrus duration in dairy goats

The object of this research was to study the effect of sterile service number on estrus duration in dairy goats. Twenty-four Nubian goats (20 nulliparous and 4 multiparous) were randomly assigned to 1 of 4 treatment groups (n = 6 animals per group). The following Groups were formed: no service (GS-0); 1 service (GS-1); 2 services (GS-2); 3 services (GS-3). Estrus was synchronized by using fluorogestone acetate intravaginal pessaries (40 mg) over a 12-d period plus 400 IU im pregnant mare serum gonadotropin (PMSG) at pessary removal. Estrus was detected by using a vasectomized buck at 6-h intervals over 5 d after pessary removal (at 0600, 1200, 1800 and 2400 h). In the GS-0 group the teaser was outfitted with an apron and was permitted to mount. In the GS-1, GS-2 and GS-3 groups, the teaser was permitted to mount and service 1, 2 and 3 times, respectively, within the first 12 h after initiation of estrus. The duration of estrus for the 4 groups (GS-0, GS-1, GS-2 and GS-3) was (mean +/- SD) 41.0 +/- 5.9, 24.0 +/- 5.4, 22.0 +/- 4.9 and 22.0 +/- 7.2 h, respectively. These results show differences between the serviced groups and the nonserviced group (P<0.01), but they fail to show differences among the serviced groups (P>0.05). It is concluded that sterile service shortens estrus duration and that service number (1, 2 or 3) does not affect estrus duration.     

Effect of service and vaginal-cervical anesthesia on estrus duration in dairy goats

The object of this experiment was to study the effect of sterile service and vaginal and cervix anesthesia on estrus duration in dairy goats. During the fall season 21 Nubian goats (9 nulliparous and 12 multiparous) were randomly assigned to 1 of 3 treatment groups (n = 7 animals per group). The following groups were formed: service (SER), vaginal and cervix anesthesia (VCA) and control (CON). Estrus was synchronized using fluorgestone acetate intravaginal pessaries (FGA, 30 mg) over a 14-d period. Estrus was detected using a vasectomized buck at 6-h intervals over 5 d after pessary removal (at 0600, 1200, 1800 and 2400 h). In the SER group the male was permitted to service each female. In the VCA group the vagina and cervix of the does were anesthesied, after which the male was permitted to service the females. Both treatments were done once within the first 12-h initiation of estrus. Does were permitted to be mounted only in the control group (CON). Estrus duration for SER, VCA and CON groups was (mean +/- SD) 24.0 +/- 10.9, 42.0 +/- 15.9 and 40.3 +/- 10.8 h, respectively. The SER group was significantly different from the VCA and CON groups (P < 0.01); however, the VCA group was not different from the CON group (P > 0.05). It is concluded that service shortens the duration of estrus due to the mechanical effect of the penis against the vagina and cervix, and not to the accessory gland fluid.     

Effect of exogenous administration of buffalo follicular fluid on follicular development, estrus response and luteal function in anoestrous goats (Capra hircus)

The effect of buffalo follicular fluid (buFF) on follicular development, estrus response and luteal function was investigated in anoestrous does. Treatment with buFF (18 ml/doe) had no significant effect on the number of antral follicles of all class categories during the period of administration. However, after cessation of buFF treatment, the number of total antral follicles increased significantly with time (P < 0.003) as well as due to the treatment × time interaction (P < 0.02), without any influence on follicle size. Injection of buFF also caused a marked increase (P < 0.049) with time in the number of medium-sized follicles at cessation. Approximately 60 and 20% of buFF-treated anoestrous does showed behavioural and silent estrus, respectively, compared to none in the control. The mean interval between cessation of buFF treatment to onset of oestrus and oestrus duration was 67.0 ± 18.5 and 17.0 ± 3.6 h, respectively. Corpus lutea size varied between 4.6 and 5.8 mm with an average diameter of 5.2 ± 0.3 mm. Only 33.3% of does showed serum progesterone levels above 1 ng/ml, while the remainder (66.7%) had below 0.5 ng/ml. Our results indicate that exogenous administration of buFF causes enhanced follicular activity following cessation of treatment, which results in behavioural oestrus and corpus luteum (CL) development in anoestrous does. CL development and its function is, however, inadequate in buFF-treated anoestrous does.     

Sequential administration of cronolone and prostaglandin F2alpha for estrus synchronization in goats.

Fifteen does received intravaginal pessaries impregnated with 20 mg fluorogestone acetate (Cronolone) at various times after the end of estrus for a period of fourteen days. The does were then treated on days 2, 4, 5, 12, or 16 after onset of estrus following the progestin treatment, with 15 mg of prostaglandin F2_α (Lutalyse) injected intramuscularly. Seventy three percent of the does showed estrus within 2 days after withdrawal of progestin treatment. Ten out of 11 does treated with prostaglandins 4 to 16 days after the end of estrus exhibited estrus within 44 to 72 hours after treatment. Breeding following the use of prostaglandin in these does resulted in a high pregnancy rate. It is concluded that a sequential use of progestin and prostaglandin may be a useful method for achieving estrus synchronization associated with high fertility in does.     

The effects of buck teasing on synchronization of estrus in goats after intravulvo-submucosal administration of cloprostenol

A study was conducted on 35 East African shorthorned female goats to determine if a combination of buck teasing and low doses of a prostaglandin (PGF(2) alpha) analogue, cloprostenol, given intravulvo-submucosally (i.v.s.m.) would be suitable for synchronization of estrus. Goats were allotted, with the onset of estrus, to seven groups (n = 5 goats per group). Five of the seven groups received varying doses of cloprostenol: Group 1 (125 mug cloprostenol i.m. per goat); Group 2 (62.5 mug cloprostenol i.v.s.m. per goat); Group 3 (62.5 mug cloprostenol i.v.s.m. per goat plus buck teasing); Group 4 (31.25 mug cloprostenol i.v.s.m. per goat); Group 5 (31.25 mug cloprostenol i.v.s.m. per goat plus buck teasing); Group 6 (buck teasing); Group 7, (2 ml physiological saline i.v.s.m. per goat, control group). Plasma progesterone concentration was measured on day of treatment and for 6 d thereafter. All goats in groups 1, 2, 3 and 5 exhibited estrus within 68 h. Thus, the number of goats receiving low doses of PG-cloprostenol intravulvo-submucosally observed in estrus increased (P < 0.05) with exposure to bucks. Exhibition of behavioral signs of estrus was maximal between 2 and 20 h after onset of signs of estrus. The exposure of females to males prior to intrauterine penetration was an advantage because copious mucus eased penetration.     

Doses of prostaglandin F(2)alpha effective for induction of estrus in goats

A total of 11 cycling does weighing between 24 and 50 kg were injected with varying dosages of prostaglandin F(2)alpha (PGF(2)alpha) between 7 and 10 days into each estrous cycle. Five injections each of 1.25, 2.5, 5.0, or 7.5 mg PGF(2)alpha were alternated with five injections of 1.0 ml saline. Saline treated does served as controls. All does were teased twice daily with a buck and observed for signs of estrus for 5 days post-injection. Daily systemic concentrations of progesterone (P(4)) were determined by radioimmunoassay. The mean (+/- S.E.) hours from injection to estrus was 47 +/- 3.3, 42 +/- 4.3, 44 +/- 8.5, and 43 +/- 5.5 for does receiving 1.25, 2.5, 5.0, and 7.5 mg PGF(2)alpha, respectively. None of the does receiving saline exhibited estrus in the 5-day post-injection observation period. Mean (+/- S.E.) concentrations of systemic P(4) in all does on the day of injection was 4.22 +/- 0.45 ng/ml. Concentrations 24 hours post-injection were 0.21 +/- 0.02, 0.15 +/- 0.05, 0.17 +/- 0.04, 0.16 +/- 0.04, and 4.5 +/- 1.36 ng/ml for does receiving 1.25, 2.5, 5.0, and 7.5 mg PGF(2)alpha, and 1.0 ml saline, respectively. The results suggested that 1.25 mg PGF(2)alpha was effective for induction of estrus in the cycling goat.     

The effects of ovarian function on estrus synchronization with PGF in dairy cows

Milk progesterone concentration (P4), milk yield, milk composition, ovarian structures and pregnancy status were studied in 108 cows treated with two doses of PGF 14 days apart and inseminated at fixed time (TAI) 80-82 h later. The synchronization protocol was started at 70+/-1.4 days after parturition. Milk P4 profiles revealed that anestrus, failure of luteolysis following treatment with PGF and failure to ovulate following luteolysis were the main reasons for low pregnancy rate with TAI. Anestrous cows had a higher percentage of milk fat (P<0.05) and higher fat to protein ratio (P<0.01), and cows that did not undergo luteolysis had higher milk yield (P<0.05) and lower percentage of milk protein (P<0.05) than cows that responded to PGF treatment. Cows that did not undergo luteolysis and cows that did not ovulate following luteolysis had lower milk P4 during the luteal phase preceding the second PGF injection (P<0.01 and P<0.05, respectively). Pregnancy rates 24 and 47 days after TAI in cows that responded as expected to the synchronization treatment were 62% and 54%, respectively. Pregnancy was precluded in non-responsive cows. The largest follicle at the time of TAI in cows experiencing late embryonic mortality was smaller (P=0.02) than in cows that successfully maintained pregnancy. Results suggest that a primary reason for low pregnancy rate in dairy cows after administration of PGF and TAI is inappropriate ovarian function prior to, or following treatment.     

The influence of ovarian status on response to estrus synchronization treatment in dairy goats during the breeding season

The influence of ovarian status (presence of a corpora lutea and follicles) on the times of the onset of estrus, LH peak and ovulation rate at a synchronized estrus was evaluated in 73 Alpine and Saanen cyclic goats. Does were treated for 11 d with 3 mg norgestomet implants or 45mg fluorogestone acetate (FGA) sponges. They also received 400 IU of PMSG and 50 μg of a PGF_2α analog on Day 9 of progestagen priming. Follicles (1 to 7 mm) and corpora lutea (CL) were counted by laparoscopy on Days 0 and 9 of progestagen treatment and 5 or 6 d after the synchronized estrus. Estrus was detected every 4 h from 16 to 60 h after the end of progestagen treatment using a vasectomized buck. The LH concentration was determined by radioimmunoassay (RIA) in blood samples collected every 4 h for 24 h beginning at the time of the onset of estrus. The number of follicles on Days 0 and 9 of progestagen treatment was not related to the time of the onset of estrus and occurrence of the LH peak or to ovulation rate. The number of CL on Day 9 influenced the time of occurrence of the LH peak but not the time of the onset of estrus. Thus, in does with 2 or 3 CL on Day 9, the LH peak occurred at 46.9 h after the end of progestagen treatment, and in does with 1 or 0 CL at 42.2 and 42.5 h, respectively, after treatment, suggesting that the number of CL at luteolysis is a factor in the variability of response after the synchronization of estrus.     

Preliminary report on induction of estrus with multiple eCG injections in Colored Mohair goats during the anestrus season

This trial was conducted to evaluate the effectiveness of multiple eCG injections in the induction of estrus and pregnancy in Colored Mohair goats during the anestrus season. It was also aimed to determine total dose of eCG required for induction of estrus. Ten multiparous and lactating goats were used. The goats were randomly divided into two groups and treatments were started on May 22. Group eCG (n=5) was treated with eCG intramuscularly for 6 days. Daily dosages of eCG from May 22 to May 27 were 300 IU, 200 IU, 200 IU, 100 IU, 100 IU and 50 IU, respectively. Goats in control group received no treatment. Blood samples were taken from animals in each of the two groups just before and after the beginning of the treatments and serum progesterone concentrations were assayed by RIA. Starting on the fourth day after the first treatments, goats were exposed to fertile bucks twice daily for 30 min to detect standing heat. The estrus goats were allowed to be mated by the bucks. Pregnancies were determined 40 days after mating by real-time ultrasonography. One goat on day 5 and three goats on day 7 exhibited behavioral estrus in eCG group (80%) after the first eCG injection. Three of them (75%) became pregnant. None of the goats in the control group exhibited behavioral estrus. Mean serum progesterone concentrations had prominent elevations indicating ovulation in eCG group, but not in control group, after 20 days from the first treatments. Progesterone concentrations of eCG group were significantly different than those of control group on days 20 and 28 (P<0.05). The results suggest that divided multiple injections of a total 950 IU eCG are effective without progestagen pretreatment in the induction of estrus and obtaining successful pregnancy and live kids in Colored Mohair goats during the anestrus season.     

Effect of sterile service on estrus duration, fertility and prolificacy in artificially inseminated dairy goats

The effect of sterile service on estrus duration, fertility and prolificacy in artificially inseminated dairy goats during breeding season was studied. Nubian does (n=126) were divided into 2 equal groups: service and control. Estrus was synchronized with intravaginal sponges containing either fluorgestone acetate (FGA; 40 mg) or medroxiprogesterone acetate (MAP; 60 mg) for 12 or 14 d, respectively. Two vasectomized teaser bucks were used to detect estrus at 6-h intervals for 5 d after sponge removal (0600, 1200, 1800 and 2400 h). The teasers were fitted with aprons and permitted to mount all does in both groups, but to penetrate only the service does within the first 12 h of estrus. Does in both groups were inseminated twice at 12 and 24 h after estrus was first detected, using 1 straw per insemination containing 200 million of cooled spermatozoa from 1 buck. The semen was placed in mid-cervix. Estrus duration for the service and control does was (mean +/- SD) 29.4 +/- 6.5 and 41.8 +/- 9.6 h, respectively. Fertility for the service does was 73.7% (46/63); for control does it was 58.7% (37/63). Prolificacy was 2.1 (96/46) and 2.0 (74/37) for service and control does, respectively. Estrus duration (P<0.001) and fertility (P<0.05) differed between the service and control group, but prolificacy was similar (P>0.05). It is concluded that sterile service reduces the duration of estrus and increases fertility in artificially inseminated dairy goats.     

Effect of progesterone impregnated vaginal sponges and PMSG administration on estrus synchronization in mares

Estrus synchronization trials with mares were carried out using progesterone impregnated vaginal sponges and pregnant mare serum gonadotropin (PMSG) injections. In Phase 1, 10 non-pregnant, non-lactating mares were administered 1 g progesterone via vaginal sponges (5 x 6 cm) without regard to stage of estrous cycle. Sponges were replaced on day 7 of trial for an additional seven days. On day 12, PMSG (1000 IU, IM) was administered to five mares (Group A); five control mares (Group B) received no injections. There was no difference (P>.05) in estrus synchronization between Group A and Group B. Total sponge retention was 75%. In Phase 2, 11 non-pregnant, non-lactating mares were administered 2 g progesterone via vaginal sponges (10 x 6 cm) without regard to stage of estrous cycle. Sponges were replaced on day 7 of trial for an additional seven days. Estrus behavior was exhibited in 54.5% of mares by day 19. Total sponge retention was 95.4%. There was no difference (P>.05) in estrus synchronization or sponge retention between Phase 1 and Phase 2. The larger Phase 2 sponges showed less (P<.01) posterior movement within the vagina than the smaller Phase 1 sponges.     

Serum LH peak and ovulation following synchronized estrus in goats

This study was aimed at comparing the temporal relationship between estrus, the LH peak and ovulation following estrous synchronization in goats using medroxiprogesterone acetate (MGA) or fluorogestone acetate (FGA). Twenty-four cyclic goats were randomly assigned to two treatments: MGA group (n = 12) that individually received a daily oral dose of 0.22 mg MGA for 12 days, and a FGA group (n = 12) treated for 12 days with intravaginal sponges containing 45 mg FGA. The goats from both groups were treated with a prostaglandin analogue (75 μg Cloprostenol i.m.) during the last day of their progesterone treatment. Estrous detection was carried out every 4 h after the end of the treatment, and blood samples for the determination of the serum LH concentrations collected at 2 h intervals for 24 h from the onset of estrus. Ovulation was detected with the aid of transrectal ultrasonography, performed every 4 h starting 15 h after the onset of estrus. All goats showed estrus. In the MGA group the onset of estrus occurred later and was more variable in relation to the end of treatment (86.7 ± 3.9 h), compared to the FGA group (44.4 ± 1.5 h; P < 0.01). The interval between the LH peak and ovulation was significantly (P < 0.05) longer in the MGA group (26.2 ± 1.1 h) than the FGA group (22.4 ± 0.8 h). There were no differences regarding the intervals from the onset of estrus to the LH peak (14.9 ± 1.8 and 15.3 ± 0.9 h) and to ovulation (40.1 ± 2.3 and 37.6 ± 0.5 h) for the MGA and FGA groups, respectively. The amplitude of the LH peak was not different between groups. It could be concluded that the timing of the LH peak and ovulation is not related to the end of treatment, but with the time of onset of estrus. The longer and more variable interval for estrous demonstration following MGA treatment, represents a serious limitation for its use in synchronization programs in goats, where mating is to be performed on a fixed-time basis.     

Restoration of endocrine and ovarian function after stopping GnRH antagonist treatment in goats

We have tested if the high number of unfertilized ova and degenerated embryos found in superovulated goats previously treated with GnRH antagonist can be related to a prolongation of gonadotrophin down-regulation and/or alterations in follicular function during the period of administration of the superovulatory treatment, around 4 days after the end of the antagonist treatment. A total of 15 does were treated with intravaginal progestagen sponges and daily injections of 0.5mg of the GnRH antagonist Antarelix for 6 days, while 5 does acted as controls receiving saline. During the antagonist treatment, the mean plasma LH concentration was lower in treated than control goats (0.5 +/- 0.2 versus 0.7 +/- 0.5 ng/ml, P < 0.0005 ); however, the FSH levels remained unaffected (0.8 +/- 0.4 versus 0.8 +/- 0.5 ng/ml). In this period, treated does also showed an increase in the number of small follicles with 2-3 mm in size ( 10.7 +/- 0.7 versus 8.4 +/- 0.6, P < 0.05), and a decrease in both the number of follicles > or =4 mm in size ( 5.0 +/- 0.3 versus 6.8 +/- 0.5, P < 0.005) and the secretion of inhibin A (120.9 +/- 10.7 versus 151.6 +/- 12.6 pg/ml, P < 0.05). After cessation of the antagonist treatment, there was an increase in LH levels in treated goats from the day after the last Antarelix injection (Day 1), so that LH levels were the same as controls on Day 3 (0.6 +/- 0.1 versus 0.6 +/- 0.2 ng/ml). However, there were even greater numbers of small follicles than during the period of antagonist injections (15.4 +/- 0.6 in treated versus 8.9 +/- 0.7 in control, P < 0.0005 ). Moreover, the number of > or =4 mm follicles and the secretion of inhibin A remained lower in treated goats (3.9 +/- 0.3 follicles and 84.4 +/- 7.0 pg/ml versus 5.4 +/- 0.5 follicles, P < 0.05 and 128.9 +/- 14.2 pg/ml, P < 0.05 ). These results indicate that pituitary secretion of gonadotrophins is restored shortly after the end of antagonist treatment, but activity of ovarian follicles is affected.     

The effect of exogenous gonadotropins on ovarian function in goats actively immunized against inhibin

The aim of this investigation was to compare the ovarian response to superovulatory treatments in does before and after inhibin immunization, with a view to optimizing the superovulatory potential of the caprine ovary. To avoid interference by the ovarian cycle, the experiment was conducted out-of-season. At the onset of the experiment 48 does were subjected to treatment with an sc implant of the progestogen norgestomet, combined with a gonadotropin; eight does each received a single injection of 1200 IU eCG, 400 IU eCG or 2 mL physiological saline (control) or six injections (at 12 h intervals) constituting 16 or 5.4 AU pFSH. The does were mated and subjected to embryo collection 6 to 7 d later. Throughout the experiment ovarian function (by ultrasonography) and plasma levels of inhibin antibodies and progesterone were monitored. Of 40 does treated during the first part of the experiment, 48% showed estrus. The ovarian response in does treated with a high or low dose of eCG or a low dose of pFSH was barely in excess of the ovarian response in the saline-treated controls, whereas a superovulatory dose of pFSH (16 AU) gave a satisfactory response of, on average, 14.5 ovulations (yielding 8.8 flushed ova and embryos). Immediately after the does had been subjected to embryo collection they were actively immunized against inhibin by administering two injections of a recombinant α-subunit of ovine inhibin at four week intervals. All immunized does produced antibodies with the maximal titer reached two weeks after the second injection. Groups of immunized does were subjected to the same gonadotropin treatments as before (avoiding allocation of individuals to the same treatments). This time all does showed estrous symptoms. The ovulatory response to the various treatments, including the saline controls, was virtually identical, the overall average being 21.8 follicles and 9.1 ovulations. The average embryo yield per doe was 5.7. The results imply that inhibin acted as the key factor in determining the ovulatory response since no impact of any of the supplementary gonadotropins was noted in inhibin-immunized does. This finding gives rise to the notion that inhibin antibodies may act primarily by an intraovarian paracrine action rather than by reducing the suppressive action of inhibin on pituitary FSH release. Further, these findings confirm earlier reports that eCG is less suitable than FSH for inducing superovulation in goats, and indicate that active immunization against inhibin may be considered a viable alternative to using exogenous gonadotropin for inducing superovulation in goats.     

Synchronization of estrus and fertility in goats with norgestomet ear implants

Estrus was synchronized in 64 dairy goats in July with norgestomet ear implants. Half the does received ear implants that contained 6 mg norgestomet and the remaining does received implants that contained 3 mg. Implants were left in place for 11 days. Each doe received i.m. injections of 400 IU PMSG and 50 mug cloprostenol 24 hours prior to implant removal. Twenty-eight of 32 does (87.5%) that received 6 mg or 3 mg norgestomet exhibited onset of estrus within 24 hours of implant removal. All does had exhibited onset of standing estrus by 43 hours after implant removal. Does were hand-mated to fertile bucks twice daily while in standing estrus. There were no differences between does implanted with 6 mg or 3 mg in fertility to the induced estrus (74.2% vs 75% kidding), mean length of gestation (151.0 +/- 3.2 vs 151.6 +/- 2.0 days), mean number of kids per doe (2.1 +/- 0.8 vs 2.3 +/- 0.7) or in mean kid weights (3.10 +/- 0.80 vs 3.06 +/- 0.86 kg) (6 mg vs 3 mg, respectively). It was concluded that ear implants that contained 3 mg of norgestomet were equally as effective as implants that contained 6 mg for synchronization of estrus in dairy goats.     

Effect of insulin administration on water drinking in children

The effect of insulin administration on water intake, was studied in children submitted to standard protocols for stimulation of secretion of hypophyseal hormones by i.v. treatment with several different drugs: insulin, insulin plus TRH and LH-RH; and propranolol, clonidine or LH-RH. Drinking was measured from 0 to 90 min after drug administration; from blood samples taken at 60 min for hypophyseal hormones analysis, microhaematocrit values were measured, as well as plasma renin activity (PRA) and glycaemia. Water intake was significantly higher in both groups of patients receiving insulin than in the control group (no insulin). Haematocrit values did not change after 60 min. There was a significant correlation of glycaemia of individuals from all three groups and water intake at 60 min. PRA was significantly higher in insulin treated individuals.     

Effects of different stimuli of service on estrus duration in dairy goats

The object of this experiment was to study the effects of different stimuli of service on estrus duration in dairy goats. Twenty Nubian goats were assigned randomly to 4 groups of 5 animals each: service (SER), mechanical stimulation of vagina (MES), accessory gland fluid insemination (AGF), and control (CON), Estrus was synchronized by using medroxyprogesterone acetate intravaginal pessaries (60 mg) over a 12-d period. Estrus was detected using 1 aproned vasectomized buck at 6-hour intervals during 5 d after pessary removal (at 0600, 1200, 1800 and 2400 h). In the SER group the male was permitted to service each female. In the MES group, stimulation was accomplished using a penis-like device maintained in the vagina 15 sec with light pressure on the fornix. In the AGF group, 1.0 ml of accessory gland fluid was deposited into the external cervical os. The CON group was only permitted to be mounted. All treatments were performed only once within the first 12 h of estrus. Estrus duration for the SER, MES, AGF and CON groups was (mean +/- SD) 22.8 +/- 5.0, 27.6 +/- 6.8, 37.2 +/- 2.7 and 42.0 +/- 9.5 h, respectively. The SER group was different from the AGF and CON groups (P<0.01), but not from the MES group (P>0.05). The MES group was different from the AGF (P<0.05) and CON groups (P<0.01). The AGF and CON groups did not differ from each other (P>0.05). It is concluded that service shortened estrus duration due to the mechanical effect of stimulation of the penis-like device against the vaginal fornix.