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Biomedical subjects

B E Seguin

Publications and source records attributed to B E Seguin.

At least 37 records · Page 2Linked to original sources
PubMed1982

Corpus luteum function and pregnancy rate in lactating dairy cows given human chorionic gonadotropin at middiestrus.

The effect of human chorionic gonadotropin (HCG) on corpus luteum (CL) function in lactating dairy cows and its subsequent effect on pregnancy rates achieved with artificial insemination was studied in two parts. In Part 1, four IM injections at intervals of seven days or two IM injections at a 14 day interval of HCG (10,000 IU) were given to two groups of six cows each, groups A and B respectively, beginning on days 9, 10 or 11 of the estrous cycle. Ten control cows were given 10 ml of isotonic saline solution on days 9, 10 or 11. Interestrous intervals were prolonged by an average of 8.1 and 3.4 days for groups A and B respectively over controls. In Part 2, 200 lactating dairy cows on nine farms were assigned, on an alternate basis at insemination, to control or treatment groups to study the effect of CL prolongation via HCG on pregnancy rate. A single injection of HCG (10,000 IU) was given 10, 11 or 12 days after a first or second insemination. Pregnancy rates for control and treated cows were similar (64 101 = 63% and 58 99 = 59% respectively). Interestrous intervals of treated nonpregnant cows were prolonged by approximately five days. Providing additional time for developing embryos to become established in utero by delaying luteolysis did not improve pregnancy rates achieved with artificial insemination in lactating dairy cows.

Journal Article↗
PubMed1981

Estradiol-17 beta cyclopentylpropionate and prostaglandin F for induction of abortion during the first trimester of pregnancy in feedlot heifers.

The ability of estradiol-17 beta cyclopentylpropionate (ECP, 20 mg) and prostaglandin F2 alpha (PGF2 alpha; 5, 10, 20, and 40 mg) to induce abortion during early gestation (days 40 to 90, as estimated by palpation per rectum) in pregnant feedlot heifers was compared. All treatments were given by IM injection. All heifers treated with 20 and 40 mg of PGF2 alpha aborted within 7 days after treatment. Six of 10 heifers aborted in the same period after ECP treatment; 1 additional heifer aborted by day 13. Abortions did not occur by day 13 in 10 placebo-treated heifers. Five and 10 mg of PGF2 alpha aborted 2 of 3 and 8 of 10 heifers, respectively, within 7 days of treatment. Quantitation of serum progesterone by specific radioimmunoassay showed that a luteolytic effect was evident in aborting heifers. Complications were not detected in any heifers after treatment or abortion. Ten of the 20 heifers that aborted in response to the 20- and 40-mg doses of PCF2 alpha developed a new corpora lutea by day 20 after treatment. However, none of the heifers that aborted after ECP treatment had a corpus luteum by day 20. It was concluded that PGF2 alpha is a more effective compound than ECP for induction of abortion during the 1st trimester of pregnancy in feedlot heifers, that a wide range of PGF2 alpha doses are capable of inducing abortion in at least some animals treated, and that heifers are likely to resume ovarian activity sooner if aborted with PGF2 alpha than with ECP.

Abortion, Induced↗
PubMed1981

Decline in assayable progesterone in bovine plasma: effect of time, temperature, anticoagulant, and presence of blood cells.

Jugular vein blood samples collected from 5 Holstein-Friesian cows during the luteal phase of the estrous cycle were incubated at 4 C, 22 C, and 37 C for 0, 0.5, 1, 2, 4, 6, 8, 12, and 24 hours. Blood samples were centrifugated after each incubation period, and plasma was frozen for later progesterone assay. Mean progesterone concentration in blood samples incubated at 4 C, 22 C, and 37 C decreased from 5.7 ng/ml at 0 hour to minimum concentrations of 3.5 ng/ml at 12 hours, 0.9 ng/ml at 12 hours, and 1.0 ng/ml at 8 hours, respectively. The first progesterone concentration which was significantly different from the initial value (0 hour) was at the 8-hour incubation period for blood samples incubated at 4 C and at the 1-hour incubation period for blood samples incubated at 22 C and 37 C. Progesterone concentration decreased similarly when blood samples were collected into heparinized tubes or EDTA tubes and incubated at 22 C for 0, 6, and 12 hours. Incubating harvested plasma or serum for 0 to 6 hours at 37 C had no effect on progesterone concentrations (7.9 and 8.2 ng/ml for plasma, and 6.9 and 6.6 ng/ml for serum.

Animals↗
PubMed1980

Effect of stage of diestrus and number of cloprostenol (ICI 80, 996) injections on intervals to estrus, LH peak and ovulation in heifers.

Intervals to the onset of estrus, luteinizing hormone (LH) peak and ovulation were compared in diestrous heifers after each of two cloprostenol treatments. Diestrous heifers were grouped at the first treatment (T1) according to day of the cycle, with heifers on days 5 through 8 designated as early diestrus and heifers on days 9 through 17 designated as late diestrus. Cloprostenol treatment was repeated (T2) 11 days after T1, at which time heifers in both groups were at similar stages of the estrous cycle. Visual observation, identification of the preovulatory LH peak, and rectal palpation were utilized to estimate data parameters. Split-plot analysis of variance showed a significant treatment x group interaction (P < .05). Time from prostaglandin treatment to the onset of estrus was similar for the early diestrous group after T1 (x = 53.1 hours ) and the early and late diestrous groups after T2 (x = 49.4 hours and 45.4 hours respectively). This interval was longer (P < .05) for the late diestrous group after T1 (x = 60.8 hours ) than for either group after T2, but not different from that for the early diestrous group after T1. Serum progesterone concentrations were higher (P < .05) at the time of T1 in the late diestrous group (x = 5.8 ng/ml ) than in the early diestrous group (x = 3.0 ng/ml ) or in either group at the time of T2 (x = 2.8 and 3.2 ng/ml respectively). Over all heifers, the synchrony of the onset of estrus was more precise (P < .05) after T2 than T1. Intervals from the onset of estrus to ovulation were not affected by group or treatment (overall mean = 24.4 +/- 1.0 hours, n = 42). We conclude that different recommendations for appointment artificial insemination (AI) may be indicated depending on the number of prostaglandin injections which are used in a prostaglandin synchronization program prior to insemination.

Journal Article↗
PubMed1979

Clinical response of dairy cattle with ovarian cysts to single or repeated treatments of gonadotropin-releasing hormone.

Two hundred twenty-five dairy cows with ovarian cysts were treated with 100 microgram of gonadotropin-releasing hormone (GnRH). Cows failing to recover were retreated with a second or third dose of GnRH. Clinical recovery following 1st, 2nd, and 3rd treatments was 76% (170/225), 78% (43/55), and 66% (8/12), respectively. Of the 221 cows that recovered, 184 eventually became pregnant. The remaining 41 cows were culled primarily as problem breeders. First-service conception rate was 49%. More ovarian cysts were detected in herds examined at 2-week intervals than in herds examined at 4-week intervals. The increased diagnosis of ovarian cysts may have been related to detection of cysts prior to spontaneous recovery that occurs in some cases. Clinical recovery from ovarian cysts was lower in herds examined at 2-week intervals following treatment, compared with those examined at 4-week intervals. The GnRH-induced luteinization of ovarian cysts and response to treatment was more difficult to judge at 2 weeks than at 4 weeks.

Animals↗
PubMed1979

The use of fibre-optic techniques in clinical diagnosis and visual assessment of experimental intrauterine therapy in mares.

Intrauterine fibroscopy was used in the clinical evaluation of 40 mares with established histories of subfertility. The average age of the mares was 12.2 years with a 2.8-year interval from last foaling in multiparous mares. Transluminal adhesions, endometrial cysts, diffuse fibrosis, fluid accumulation or myometrial tumours were found in 26 mares. When compared to other techniques, fibroscopy did not seem to be superior to uterine biopsy but had some advantage over rectal palpation as a single diagnostic technique. Only 3 mares failed to exhibit pathological findings when all 3 techniques were used. A second study was conducted to examine visually the effect of infusing various antibiotics and disinfectants into the uteri of clinically normal dioestrous mares. Fibre-optic examinations were performed before and after infusion of 3 mares/treatment. No gross pathological changes were seen 3 days after infusion of potassium penicillin, chloramphenicol succinate or a soluble oxytetracycline powder in a dextrose base. Lugol's solution caused severe inflammation, fibrin deposition, and ulceration of the endometrium. Ampicillin resulted in a white precipitate which adhered to the the endometrium for 10 days after treatment.

Animals↗
PubMed1976

Gonadotropin releasing hormone induced luteinizing hormone release after prostaglandin F2alpha in heifers.

Twenty Holstein heifers in diestrus were given 30 mg of PGF2alpha Tham salt (im). Thereafter each of five heifers received no further treatment of 40 mug of GnRH (im) at 10, 30, or 50 hr after PGF2alpha. Serum progesterone decreased to less than 1 ng/ml at 24 hr after PGF2alpha and remained low throughout the remainder of the sampling period. Following PGF2alpha, estradiol concentrations increased gradually in serum but GnRH given at 30 hr after PGF2alpha abruptly decreased estradiol concentration. The magnitude of LH release induced by GnRH given at 30 or 50 hr after PGF2alpha was greater than that at 10 hr. All heifers exhibited behavioral estrus except those in group GnRH-50. Spontaneous LH peaks, which usually occur after PGF2alpha were observed in 5/5 (control), 4/5 (GnRH-10), 0/5 (GnRH-30), and 2/5 (GnRH-50) heifers. We conclude that pituitary responsiveness to GnRH increases with time after PGF2alpha and GnRH given at 30 hr completely inhibits and at 50 hr partially inhibits endogenous LH release.

Animals↗
PubMed1976

Effect of gonadotropin-releasing hormone and human chorionic gonadotropin on cows with ovarian follicular cysts.

Ovarian follicular cysts of cattle were defined as follicular structures (larger than or equal to 2.5 cm, diameter) which persisted for 10 days or longer in the absence of functional luteal tissue. Thirty dairy cows with ovarian follicular cysts were allotted to 6 groups (5 cows per group) and each was given 0 (saline solution), 25, 50, 100, 150, or 250 mug of gonadotropin-releasing hormone (GnRH) by intramuscular (IM) injection. Samples of blood were collected before GnRH was injected (0 hour), at 0.25, 0.50, 0.75, 1, 2, 3, and 4 hours, and at 1, 7, 11, 15, and 20 days after treatment. Five additional cows with follicular cysts were treated IM with 10,000 units of human chorionic gonadotropin (HCG), and blood sample collections were made before treatment (0 hour) and on days 1, 7, 11, 15, and 20 after treatment. Serum luteinizing hormone (LH) concentration was not altered in cows given saline solution, but was increased significantly in cows given any of the doses of GnRH (in a dose-related manner). Peak LH responses occurred about 2 hours after GnRH was given, and by 4 hours LH was beginning to decrease. Serum progesterone concentrations increased by more than 2.0 ng/ml by day 11 after treatment in 18 of 20 cows treated with 50, 100, 150, or 250 mug of GnRH. Progesterone responses in these cows were greater (P less than 0.05) than in cows given saline solution or a 25-mug dose of GnRH. Mean progesterone response to the 4 large doses of GnRH was similar in magnitude and duration to serum progesterone changes during the leutal phase of the bovine estrous cycle. After cows were treated with HCG, serum progesterone values were similar to those in cows given GnRH (50 to 250 mug).

Animals↗
PubMed1975

Luteolysis, estrus and ovulation, and blood prostaglandin F after intramuscular administration of 15, 30 or 60 mg prostaglanding F2alpha.

During diestrus in three consecutive estrous cycles, each of six heifers was given (im) 30 mg, 15 mg (twice at 6-hr intervals) and 60 mg prostaglandin F2alpha (PGF2alpha) tham salt. Neither the decline in blood progesterone, the increase in blood estradiol, the duration or the peak of the LH surge, the interval to onset of estrus, nor the interval to ovulation was affected significantly by dose of PGF2alpha. Thus, relative to that after 30 mg PGF2alpha im, two injections of 15 mg at 6-hr intervals or 60 mg PGF2alpha did not hasten luteolysis. Thirty mg was an ample in dose of PGF2alpha to cause luteolysis. Regardless of im dose of PGF2alpha, blood PGF peaked at about 6.0 ng/ml within 10 minutes and returned to basal values (less than 1.0 ng/ml) within 90 minutes. In another trial, after a single iv injection of 5 mg PGF2alpha, blood PGF peaked (25 ng/ml) within 5 minutes and returned to basal values within 15 minutes. During a 30-minute infusion (0.5 mg/minute) of PGF2alpha, blood PGF plateaued at 29.5 ng/ml with a metabolic clearance rate of 17.0 liters per minute.

Animals↗