Post-treatment Estrus Research Articles

Evaluation of Efficacy of Herbal Intrauterine Infusion Uterofix Liquid in Treatment of Various Reproductive Disorders in Cows: A Field Study.

Objective:To evaluate the efficacy of herbal intrauterine infusion Uterofix liquid in the treatment of various reproductive disorders in cows.Materials and Methods:Based on symptoms of endometritis, anestrous, metritis, and repeat breeders, 28 cows were selected to study the efficacy of herbal intrauterine infusion Uterofix liquid (M/S Ayurvet Limited) in uterine infections study. Group T0 (n = 8) cows served as control group, no treatment was given to this group, Group T1 (n = 5) repeat breeder cows, Group T2 (n = 5) endometritis effected cows, Group T3 (n = 5) anoestrus cows, and Group T4 (n = 5) metritis suffered cows were treated with Uterofix liquid (25 ml as intrauterine infusion once a day for 3–5 days). Total observational period was 60 days. Number of treatments needed, nature of discharge in first posttreatment estrus (physical examination), after treatment number of animal showing heat/estrus out of total treated, and posttreatment conception rate were used as criteria to judge the success or failure of treatment.Results:Results revealed that 18 out of 20 animals (90%) showed signs of heat with clear discharge, recovered completely without causing any irritation, or severe irritation/sloughing of genital mucous membrane after Uterofix liquid treatment.Conclusion:Herbal intrauterine infusion Uterofix liquid significantly treated the uterine infections in cows.SUMMARY Uterine infection is a major problem in reproductive management. A wide variety of genital tract diseases of female domestic animals are known to produce significant losses and responsible for poor fertility. Amongst these highly prevalent are metritis and repeat breeding in high-producing dairy cows which if remains untreated are associated with low conception rate per artificial insemination (AI), extended interval to pregnancy, increased culling, and economic losses. As herbal remedy the Uterofix liquid (Ayurvet Limited, India) was highly efficacious as an intrauterine infusion to treat different reproductive disorders.

Low plasma progesterone concentrations are accompanied by reduced luteal blood flow and increased size of the dominant follicle in dairy cows

To investigate the influence of low plasma progesterone (P 4) concentrations on luteal and ovarian follicular development as well as endometrial gene expression in the concomitant and subsequent estrous cycle, 20 lactating dairy (Holstein Friesian and Brown Swiss x Holstein Friesian) cows received either a single treatment with 25 mg prostaglandin F 2α (PGF 2α) on Day 4 Hour 12 (PG1; n = 8), or two treatments (25 mg PGF 2α each) on Day 4 Hours 0 and 12 (PG2; n = 12) of the estrous cycle (Day 1, Hour 0 = ovulation). In four cows, ovulation occurred between 4 and 6 d after the second PGF 2α treatment; these cows and one lame cow were excluded. In the 15 remaining cows with physiological interovulatory intervals (18 to 24 d), P 4, luteal size (LS) and blood flow (LBF), as well as follicular size (FS) and blood flow (FBF), were determined daily until Day 4, immediately prior to (0 h) and 12 h after each PGF 2α treatment, and then every 2 d, from Day 5 to 8 d after the subsequent ovulation. Because P 4 did not differ (P > 0.05) between PG1 and PG2, cows were regrouped according to their mean P 4 concentration from Days 7 to 15, either P 4 <2 ng/mL (P 4L; n = 7) or P 4 >2 ng/mL (P 4H; n = 8). In the treatment cycle, LS was smaller in P 4L than P 4H on Days 13 (P = 0.01) and 15 (P = 0.03), and LBF was lower in P 4L than P 4H on Day 15 (P = 0.02). The dominant follicle of the first follicular wave was larger in P 4L than P 4H on Days 13 (P = 0.03), 15 (P = 0.03), and 17 (P = 0.01). In the subsequent cycle, there were no significant differences between P 4L and P 4H for P 4, FS, LS, and LBF; however, FBF was lower (P = 0.01) in P 4L than P 4H on Day 7. In Group P 4L, endometrial expressions of estrogen receptor α and oxytocin receptor were lower (P = 0.05 and P = 0.03, respectively) at the estrus that preceded treatment compared to the post-treatment estrus. In summary, low P 4 during diestrus was associated with smaller LS, reduced LBF, and larger FS in the treatment cycle, but not in the subsequent cycle.

Effect of Administration of Garlic Extract and PGF2慣 on Hormonal Changes and Recovery in Endometritis Cows

The efficacy of garlic extract and PGF 2 α in the treatment of endometritis in cows was evaluated. A total of 26 parous cows affected with endometritis were randomly allocated into three groups. Group I (n = 10) animals were infused (IU) with 10 ml garlic extract mixed with 90 ml normal saline, three times at 12 h interval starting from the day of estrum, whereas the animals of Group II (n = 10) were treated with a single injection of PGF 2 α (25 mg Lutalyse) on the 10 th to 12 th day after estrus, and group III (n = 6) remained as control. Cervico-vaginal mucus (CVM) was collected from each animal at pre- and post-treatment estrus and subjected to white side test, pH determination and total bacterial load. The clinical recovery of cows was assessed by negative white side test reaction, pH value and total bacterial count of CVM at subsequent estrus. The recovered animals were inseminated with frozen-thawed semen twice at 12 h intervals and pregnancy was confirmed at 45-60 days following insemination. A significant decline (p<0.05) in pH of CVM was observed in both the treatment groups at subsequent estrus. After treatment there was a significant (p<0.05) reduction in bacterial load, whereas, it was increased in control group. A total number of 65 isolates were identified in CVM samples comprising mostly of facultative anaerobic bacteria. Plasma T 4 and T 3 concentrations were increased in all the treated animals, whereas, a decline was observed in cortisol levels following treatment. The overall conception rate was 50% in treated groups as compared to nil pregnancy in the control.

Maternal recognition of pregnancy in swine. II. Plasma concentrations of progesterone and 13,14-dihydro-15-keto-prostaglandin F2 alpha during the estrous cycle and during short and long pseudopregnancy in gilts.

Two experiments were conducted to determine plasma progesterone (P4) and 13,14-dihydro-15-keto-prostaglandin F2 alpha (PGFM) concentrations in unmated gilts induced to have either short pseudopregnancy (SPP) or long pseudopregnancy (LPP). In experiment 1, estradiol-17 beta (E2) was injected on different combinations of days between Days 11 and 16 of the estrous cycle. For gilts induced to exhibit SPP, the interestrous interval averaged 27.0 +/- 0.4 days compared to the control interval of 20.0 +/- 0.4 days. In experiment 2, E2 injections were given on Days 12 and 13 or on Days 12 through 25. Interestrous intervals in SPP and nonpseudopregnant gilts were 25.6 +/- 0.2 and 19.9 +/- 0.6 days, respectively. Four of six gilts treated with E2 on Days 12-25 were induced to have LPP lasting more than 100 days. In both experiments, plasma P4 declined to baseline approximately 3 days before posttreatment estrus, regardless of type of pseudopregnancy induced. Plasma PGFM peaked 4-6 days before posttreatment estrus in gilts displaying each type of response. In gilts exhibiting LPP, plasma PGFM concentrations tended to increase steadily during pseudopregnancy. These data suggest that the mechanisms of luteolysis during the estrous cycle of unmated gilts and during estrogen-induced SPP and LPP may be similar. The present results suggest that luteal persistence during SPP and LPP may be due to delayed peak release of prostaglandin F2 alpha by the uterus.

Effect of persistent follicles on early embryonic losses in beef cows.

Low doses of progestogens in regimens for synchronization of estrus result in persistent follicles (PF) and reduced conception rates in cattle. The effects of PF on recovery of oocytes/embryos, fertilization, and embryonic development were examined in beef cows. To produce PF, cows received a used Controlled Internal Drug Releasing device on Days 4 through 13 after pretreatment estrus (Day 0) and two injections of 20 mg prostaglandin (PG) F2 alpha, i.m., 12 h apart on Day 6 (PF; n = 20). Control cows received only PGF2 alpha on Day 6 so they would ovulate growing follicles (GF; n = 22). With this model, the largest (dominant) follicle from the first wave of follicular development was being ovulated in cows in each group. Cows were observed for estrus twice daily and were then mated to highly fertile bulls. Follicular development was monitored by ultrasonography on alternate days from Day 2 until estrus and then daily until apparent ovulation. Jugular blood samples were collected every other day from Day 2 through 6 days after mating at posttreatment estrus, when uteri were flushed nonsurgically. The ovulatory follicle, which was followed retrospectively and had been observed longer (14 +/- 1 vs. 8 +/- 1 days), was larger in PF (17.2 +/- 0.5 mm) than in GF (14.5 +/- 0.6 mm; p < 0.01). Mean estradiol-17 beta (E2) in jugular plasma during the 6 days before estrus was higher in PF than in GF (5.7 +/- 0.4 vs. 2.6 +/- 0.4 pg/ml; p < 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Progesterone and estradiol in biodegradable microspheres for control of estrus and ovulation in mares

Progesterone and estradiol 17-β in poly (DL-lactide) microspheres were used to control estrus and ovulation in mares after luteolysis was induced by prostaglandin F 2∞. Mares were given a single intramuscular injection of biodegradable poly (DL-lactide) microspheres, 1 day following prostaglandin treatment, containing no hormones (control), 0.625 g progesterone and 50 mg estradiol (low dose), 1.25 g progesterone and 100 mg estradiol (medium dose), or 1.875 g progesterone and 150 mg estradiol (high dose; n=15 mares per group). Mares treated with the low dose had significantly longer intervals (P<0.05) to estrus and ovulation than the control mares; however, low dose mares had shorter intervals (P<0.05) to estrus than high dose mares and shorter intervals to ovulation than medium and high dose mares. Regression analysis indicated that the medium dose was sufficient for maximizing interval to ovulation while the high dose maximized interval to estrus. All groups of mares exhibited similar (P>0.05) post-treatment estrus lengths. A clinical response scoring system based on synchrony of both estrus and ovulation within a treatment group was also used to measure the effectiveness of treatments on control of estrus and ovulation. Clinical response scores did not differ (P>0.05) among treatment groups. Mares were randomly assigned for insemination at the beginning of the first post-treatment estrus. Rates for embryo recovery performed by uterine lavage 7 days post-ovulation did not differ (P>0.05) among groups. Concentrations of serum progesterone increased in mares receiving progesterone and estradiol microspheres. At 10 to 14 days post-injection of microspheres, progesterone concentrations were higher (P<0.05) and remained above 1 ng/ml in the mares receiving the high dose. Progesterone concentrations were also higher (P<0.05) on Days −3 to −1 (Day 0 = day of post-treatment ovulation) in mares receiving the high dose when compared to control mares. Gonadotropin concentrations were suppressed (P<0.05) in the medium and high dose groups.

Endocrine and reproductive responses of beef cattle to a synthetic gonadotropin-releasing hormone agonist (fertirelin acetate)

A synthetic gonadotropin-releasing hormone (GnRH) agonist (fertirelin acetate, FA) was administered to beef cattle within 12 h after onset of estrus (Day = 0) to study effects on subsequent endocrine responses and fertility. In Study 1, 16 crossbred beef heifers were injected with either 100 μg FA (n = 8) or saline (n = 8) at 6 or 12 h (n = 7; n = 9) after onset of estrus. Concentrations of luteinizing hormone (LH) over time were affected (P<0.01) by the interaction of treatment and interval from onset of estrus to treatment. Heifers treated with FA at 6 h after onset of estrus exhibited the greatest increase in LH after treatment. There was no effect of treatment, interval from onset of estrus to treatment or treatment by interval interaction on duration of the estrous cycle, on concentrations of progesterone from Days 1 through 14 posttreatment, or on concentrations of progesterone prior to subsequent estrus (Day −10 through 0, posttreatment estrus). In summary, FA administered to beef cattle within 12 h after onset of estrus effectively increased peripheral plasma concentration of LH, but this increase had no effect on subsequent luteal function as measured by duration of the estrous cycle or concentrations of plasma progesterone. In Study 2, 86 parous beef cows were bred artificially to one of two bulls following natural or prostaglandin F 2α induced estrus. Cows received either no treatment or 50 or 100 μg FA at the time of AI. There was no effect of treatment, breed, parity, technician, service sire or interactions on conception rate (mean = 76.7%). Although not significant, the numerical pattern of conception rate among experimental groups (control = 71.4%, 50 μg FA = 76.7%, 100 μg FA = 82.1%) supports further investigation of this GnRH agonist with larger numbers of cattle.

Reproductive Responses, Progesterone Profiles and Ovarian Characteristics of Cycling, Fine-Wool Ewes Treated with an Inhibitor of Progesterone Synthesis (Epostane)

In Exp. 1, 45 fine-wool ewes received (sc) either 0, 50 or 100 mg epostane (3-beta-hydroxysteroid dehydrogenase inhibitor) to examine effects on return to estrus and conception rates. Treatments were imposed on d 10 of an estrous cycle (estrus = d 0) and jugular blood samples were collected once daily on d 8 and 9, twice daily on d 10 through 13 and once daily from d 14 until first post-treatment estrus or d 20 (15 ewes/treatment). Intensive samples were obtained hourly for 6 h after treatment (d 10; five ewes/treatment). Serum progesterone (P4) before treatment was similar among groups; but by 2 h after treatment, epostane-treated ewes had lower (P less than .10) values than controls. By 6 h post-treatment, serum P4 in ewes receiving 50 (1.0 ng/ml) and 100 (.9 ng/ml) mg epostane was well below control values (3.2 ng/ml). By 7 d after treatment, 93.3% of ewes treated with 50 mg epostane had recycled compared with 66.7 and 33.3% of those receiving 100 and 0 mg, respectively (P less than .10). Similarly, 93.3, 53.3 and 26.7% of ewes receiving 50, 100 or 0 mg epostane, respectively, lambed to breeding within 7 d of treatment (P less than .05). Overall conception rates during a 34-d breeding season were similar among groups. Preweaning performance of offspring did not differ among maternal treatments.(ABSTRACT TRUNCATED AT 250 WORDS)

Serum and milk progesterone in Syncro-Mate-B treated postpartum beef cows

Fifteen post-partum (61.5±6.1 days) cyclic beef cows (4.1±0.3 years old) were randomly assigned to receive the Syncro-Mate-B (SMB) treatment on day 0 (estrus), day 9 or day 18 of their cycle with implant removal nine days later. An additional five post-partum (41.7±5.6 days) beef cows (3.2±0.4 years old) not detected in estrus and without corpora lutea also received the SMB treatment. Blood samples (10ml) were obtained via venipuncture on the day of implantation and one, three, five, seven and nine days after implantation and ten days after the post-treatment estrus. Milk samples (25 ml) were obtained by hand stripping at the same periods. Nineteen of twenty cows were synchronized, i.e. estrus occurred within five days of implant removal. Progesterone concentrations in both serum and milk were similar and followed similar patterns for each group. The day-9 treated cows had greater serum and milk progesterone concentrations than the other groups of cows on days 1, 3, and 5 after implantation. In conclusion, cows treated with SMB had similar serum and milk progesterone concentrations, endogenous progesterone secretion was inhibited by SMB treatment and the inhibition was influenced by prior luteal function.

Ovarian activity and hormonal patterns in gilts fed allyl trenbolone.

A study was conducted to establish the profile of reproductive hormones and the degree of ovarian activity in gilts fed either 2.5 or 15.0 mg of allyl trenbolone (AT) daily. Progesterone levels following regression of corpora lutea remained low (less than 1 ng/Ml) during progestin treatment. In gilts given 2.5 mg AT, plasma estradiol (E2) levels fluctuated between 7 and 13 pg/ml during treatment and began to decrease by day 2 after withdrawal of AT. Gilts given 15 mg of AT had lower (P less than .01) plasma concentrations of E2 (2.5 pg/ml) during treatment; concentrations began to increase the day after withdrawal of AT, reaching a maximum of 13.1 pg/Ml in 3.5 to 4.0 days. Luteinizing hormone (LH) levels were low (less than 1.5 ng/ml) during AT treatment. Daily feeding of AT prevented estrus in all gilts. A preovulatory surge of LH (4 ng/ml) was observed on the first day of the first post-treatment estrus. Gilts given 2.5 mg of AT daily had more (P less than .01) follicles of ovulatory size during treatment and a higher frequency of cystic follicles after withdrawal than gilts given 15 mg of AT daily. Estrus was effectively synchronized in gilts given 15 mg of AT daily, whereas the feeding of 2.5 mg AT daily resulted in an increased incidence of anestrus.

FERTILITY OF ESTRUS SYNCHRONIZED DAIRY HEIFERS TREATED WITH CAP ALONE OR IN COMBINATION WITH ESTRADIOL BENZOATE. HCG OR GnRH

The possibility that improvement in conception rates in chlormadinone-acetate (CAP)-treated heifers might be obtained by application of estradiol benzoate (EB) human chorionic gonadotropin (HCG) or GnRH shortly before the 1st insemination was investigated. Over a 3-year period a total of 206 German red pied heifers were used. 1/2 were used to determine the effect of the additional hormones on the conception rate. CAP was given orally in doses of 10 mg/day for 18 days. In Experiment 1 42 heifers were given CAP only and 39 were additionally given EB 5 mg im 24 hours before insemination. In Experiment 2 38 heifers were given CAP alone and 35 were also given 1000 IU HCG iv 6 hours before the 1st insemination. In Experiment 3 22 heifers were given only CAP and 30 were also given 1.5 mg of GnRH iv 5 hours before the 1st insemination. All of the inseminations were done with frozen semen after withdrawal of CAP therapy. In some animals 2nd inseminations were given. Pregnancies were confirmed by rectal exploration at 6-7 weeks after the last insemination. In Experiment 1 with EB heifers showed improved estrous symptoms but the pregnancy rate was the same as controls. In Experiment 2 with additional HCG treatment the conception rate was 20% lower than with only CAP treatmen t (p less than .05). In Experiment 3 with additional GnRH therapy the p regnancy rate was 26.9% higher than with only CAP therapy (p less than .05). In all 3 experiments 80% of all animals failing to conceive showed a regular cycle in the 1st posttreatment estrus. Only those which in addition had received EB showed subsequent irregular prolonged estrous cycles (p less than .05). Pregnancy rates in the experimental heifers were lower than usually obtained in nonsynchronized ones. Other investigators have reported better results. Postestrial bleeding did not influence pregnancy rates. It is concluded that after the CAP therapy estrus and time of ovulation had occurred over more than 3 days. Therefore no optimal service time could be determined. In heifers treated with only CAP the conception rate ranged from 33.3 to 36.4% when these heifers were artifically inseminated without regard to estrus on Days 3 and 4 following the cessation of CAP feeding. The only improvement of the pregnancy rate was obtained by injection of 1.5 mg GnRH 5 hours before insemination in CAP-synchronized heifers. The major causes of low fertility are thought to take place at the time of ovulation and fertilization.

Pattern of luteinizing hormone release in progestin-treated ewes.

Two experiments were conducted with yearling ewes to study the pattern of release of LH at the first and second estrous periods following progestin treatment and the effect of dose of progestin on the time of LH release at the first post-treatment estrus. In experiment 1, data were obtained at first and second post-treatment estrus on 43 of 100 ewes which had been assigned at random to treatment during one of 4 months of the breeding season (September through December). Treatment consisted of an intravaginal sponge containing 20 mg flurogestone acetate (Cronolone) for a period of 13 days. For experiment 2, 24 animals were assigned at random to each of two treatments. These ewes received intravaginal sponges containing either 20 or 40 mg flurogestone acetate for 13 days. The results from experiment 1 showed a significant (P< 0.01) effect of month on the number of ewes showing estrus within 72 hr. post-treatment.

Synchronization of Estrus, Reproductive Performance, and Lactational Response of Holstein Heifers Treated with Melengestrol Acetate®,1

Effects of oral administration of melengestrol acetate on estrus synchronization and conception were investigated in 24 Holstein heifers. In addition, effects of feeding melengestrol acetate starting at 90 days postconception through 30 days postpartum on growth, gestation length, birth weight, and lactation were studied.Daily feeding of 1mg of melengestrol acetate to heifers for 14 consecutive days irrespective of stage of estrous cycle inhibited estrus during treatment and synchronized estrus following withdrawal. Treatment lowered (P<.05) conception at first post-treatment estrus. No difference in conception was observed between single and double inseminations. Services per conception for the treated animals were higher (P<.05) than controls (2.64 versus 1.54). Postconception feeding of melengestrol acetate resulted in no differences (P>.05) in weight gain, gestation length, or calf birth weight. There were no differences (P>.05) in lactation length, milk and fat production during post-treatment lactation.

Synchronization of estrus in dairy cattle with 17-alpha-ethyl-19-nortestesterone (Nilevar).

Daily subcutaneous injections of levels of less than 4.8 mg/d of 17-a-ethyl-19-nortest-osterone (Nilevar) were not successful in completely inhibiting estrus. Estrus in seven cows receiving 4.8 mg/d was successfully synchronized, and six of the seven cows settled at the post-treatment estrus. Oral doses of 24 mg/d, 48 mg/d, and 96 mg/d were not successful in inhibiting estrus. Round vaginal pessaries were expelled by mature dairy cows within 40 hr. from time of insertion. Twelve hydron plastic implants containing either 75 mg, 200 mg, or 300 mg of Nilevar were inserted approximately 10 cm lateral to the first lumbar vertebra. The 75 mg and 200 mg implants did not effectively inhibit estrus, but the 300 mg implants inserted on days 2, 12 and 16 of the estrual cycle inhibited estrus until removal 17 days later.

Effect of Melengestrol Acetate on Synchronization of Estrus, Subsequent Fertility and Milk Constituents of Lactating Dairy Cows

The oral effectiveness of melengestrol acetate in estrus synchronization and its effect on milk yield and milk constituents was determined in 40 lactating dairy cows. Melengestrol acetate was fed at a rate of 1.0 mg/head/day for 14 consecutive days in 0.91kg of a grain diet. It was observed that melengestrol acetate did not significantly affect milk yield, milk fat, solids-not-fat, or lactose level. Cows were not observed in standing estrus during the feeding period of melengestrol acetate. The occurrence of estrus after withdrawal was 93%. The mean interval from melengestrol acetate withdrawal to onset of the first and second post-treatment estrus was 4.9 and 21.9 days, respectively. The over-all conception rate (first and second service) for the control group was 53%, as compared to 60% for the melengestrol acetate group. Estrus synchronization in the hot summer months tends to have a slight adverse effect on the occurrence of post-melengestrol acetate estrus and on fertility, when compared to estrus synchronization during the cool seasons of the year.

SYNCHRONIZATION OF ESTRUS AND ARTIFICIAL INSEMINATION IN BEEF CATTLE

Fifty Aberdeen Angus cows were group-fed 1 kg of meal containing 10 mg of 6-chloro-Δ6-17 acetoxyprogesterone (CAP) per female per day for 14 days, followed by 1 kg of meal containing 5 mg of CAP per female per day for 4 days. Twenty-five cows were injected with 1,000 IU of human chorionic gonadotrophin (HCG) 48 hr after the last CAP feeding. The cows injected with HCG were artificially inseminated 12–24 hr after the injection. Non-injected cows were inseminated approximately 12 hr after the onset of standing heat. CAP was successful in suppressing estrus in 47 (94%) of the cows during the feeding period. Seven of the 20 non-injected cows which showed heat conceived to the first post-treatment service. Six of the 15 HCG-injected cows which showed heat and four of the 10 HCG-injected cows which did not show heat conceived to the first post-treatment service. Of the 27 cows which showed a second post-treatment estrus and were inseminated, 13 cows conceived, giving a total of 30 cows conceiving to the artificial insemination services. The HCG injection had no significant (P &gt; 0.05) effect on the incidence of estrus or conception; however, it did eliminate the problem of detecting estrus and significantly (P &lt; 0.01) reduced the time required for restraining and inseminating the cows.

Influence of Exogenous Progesterone on Follicular Cysts in Dairy Cattle

Daily injections of progesterone for 14 days into animals with follicular cysts resulted in normal estrus in 61.5 and 62.5% of those on the 50- and 100-mg daily dosage level, respectively. The 50-mg dosage level resulted in 19 conceptions from 39 (48.7%) treatments while in those on the 100-mg dosage level, 21 conceptions resulted from 40 (52.5%) treatments. Some animals received a second or third series of injections. Of those treated one or more times, 58.8% conceived. Of 30 control animals, four (13.3%) conceived. The 50-mg dosage level was more effective in controlling the time of post-treatment estrus.

HORMONAL CONTROL OF REPRODUCTION IN EWES DURING THEIR NORMAL BREEDING SEASON

Injected or orally-administered progestagens have been shown to synchronize estrus in mature ewes during their normal breeding season. Oral administration of 6–methyl-17-αα-acetoxyprogesterone (MAP) or 6-chloro-Δ6-dehydro-17-acetoxyprogesterone (CAP) for 10 days was more effective in synchronizing estrus than intramuscular injections of repositol progesterone. CAP appeared to be more active in controlling breeding activity than MAP (2.5 mg CAP per head vs. 60 mg MAP per head). The administration of 2.5 mg CAP per head per day for 18 days was as effective as the feeding of 3.5 mg per head per day for 10 days. CAP, at a dosage level of 2.5 mg, administered over a 10-day period to motivate first post-treatment estrus, was more effective when injected intramuscularly than when administered orally. The administration of Pregnant Mare Serum did not result in an increase of lambing percentage.

Effect of intrauterine administration of a viscous gel-like substance on the estrous cycle in cattle. II. Irritating effects of the treatments on the uterus

In the previous report, we investigated the effects of intrauteine injection of a viscous gel-like substance on the life span of the corpus luteum in the cow. The intrauterine treatment at early luteal phase caused an early regression of the corpus luteum and shortened the cycle length significantly. On the contrary, the treatment at late luteal phase delayed the regression of the corpus luteum and lengthened the cycle. The purpose of the present experiments is to investigate the relation between the irritating effects of the intrauterine injection of the viscous gel-like substance on the endometrium and the modification of the cycle length in the cow. The viscous gel-like substance was “Gelceptor F” (G) which was same as in the previous report.Three experiments were performed to determine 1) the retention of G in the uterus of the treated cow, 2) the irritating effects of the treatment on the bovine endometrium and 3) the effective period of the uterine irritation for modifying the cycle length of the cow.The cows used in the present experiments were almost same as in the previous report. Dose of G was 42-137 gm. per injection. The day on which ovulation occured was considered as day 0 of the cycle. The results obtained were as follows.1) The retention of G in the uterus of the treated cow. The retention of in G the uterus was verified by rectal palpation on 32 cycles of 9 cows in which intrauterine injections of G had been performed 1 to 5 times. The results are shown in Table 1. In only 3 of 16 cases treated during postestrus and in early luteal phase, liquid contents in the uterus were palpable for a few days after the treatment. After treatment during functional luteal phase and late luteal phase, uterine contents were palpable for 2 to 3 days in 10 of 16 cases. In 5 of the latter cases the uterus was swollen as in the case of pyometra or pregnancy. However, the swollen uterus involuted rapidly as the corpus luteum began to degenerate. From these results it was concluded that the retention of G in the uterus depended upon the stage at which the intrauterine injection was performed, the retention period being longer in animals treated at postestrus-early luteal phase.2) The irritating effects of the treatment on the bovine endometrium.A. Responses of cervical mucus following the treatment.: On 20 estrous cycles included in experiment 1, cervical mucus samples collected before and after the treatment were examined macroscopically and microscopically. The microscopical examination was performed on the mucus smear stained with Giemsa. The results are shown in Table 2. For 1 to 3 days after the treatment, the cervical mucus became cloudy or greyish white and a large number of neutrophil leucocytes and epithelial cells and a small number of eosinophil leucocytes appeared in most of the cases. However, cervical mucus became clear again in the following estrous period.B. Effects of the treatment on the endometrium.: The endometrium of seven beef cows slaughtered 1 to 9 days after the intrauterine treatment was examined macroscopically. In an additional 5 cases, the endometrium at the first post-treatment estrus was also examined histologically by endometrial biopsy. The results are shown in Table 3. In five of the seven animals, 105 to 330 gm. of brownish liquid were recovered from the uterine cavity. The volume of the uterine contents recovered was greater than the quantity of G injected. The surface of the endometrium was rough and brownish in colour in six of the animals. Marked edema was also observed in the endometrium of five animals. Endometritis was found four of the seven animals. However, the endometritis was limited to the surface area of the endometrium only. The uterine glands appeared normal in all cases. In five animals in which endometrial biopsies were carried out at the post-treatment estrous period, endometritis was not found in any of them.

Control of Estrus and Lambing Performance in Cycling Ewes Fed 6-Methyl-17-Acetoxyprogesterone

Estrus was suppressed by the consistent consumption of 20 mg. or more of 6-methyl-17-acetoxyprogesterone (MAP) per day for 14 days by ewes previously experiencing normal estrous cycles. When levels of consumption were maintained at 40 to 75 mg. of MAP per head per day for 14 days, post-treatment estrus and in most cases the subsequent lambings were grouped. The group feeding of 50 or 75 mg. of MAP per ewe daily produced results similar to those obtained when ewes were individually fed.