A Comparison of Effects of Zearalenone and Estradiol Benzoate on Reproductive Function during the Estrous Cycle in Gilts (original) (raw)
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Animal Reproduction Science, 1989
Berghorn, K.A., Edgerton, L.A., Cromwell, G.L. and Stahly, T.S., 1989. Serum progesterone and luteinizing hormone following prostaglandin Fz~ during the sow's estrous cycle. A nim. Thirty -six sows and gilts (hereafter called sows ) received one of three prostaglandin F2~ ( PGF~,~ ) treatments on day 6, 10, or 14 of the estrous cycle to determine the effect of prostaglandin treatment on subsequent concentrations of luteinizing hormone (LH) and progesterone. Also, the effect of treatment on estrous cycle lengths was evaluated. Blood was sampled every 15 min fl)r 6 h. Starting from time 0, sows received 25 mg of PGF2~ at 4 h (treatment 1), 50 mg at 4 h (treatment 2), or 25 mg at both I h and 4 h (treatment 3). Treatment and day of cycle that sows were treated modified estrous cycle lengths (P< 0.05). Release of LH was episodic prior to PGF~,~ treatment. After PGFz~ injection, progesterone in blood sera increased (P< 0.0001 ) with higher progesterone continuing for about 1 h. Concentrations of LH in blood sera decreased fbllowing PGF~,, suggesting negative feedback of progesterone. Initial response of LH and progesterone to PGF2,~. was not distinguishable (P > 0.05 ) among the three cycle stages nor altered by quantity of PGF2,~ although the response to a second injection (treatment 3) was diminished (P< 0.01 ). Correlations between LH and progesterone were not significant (P > 0.05 ) at any time. Therefore. it appears that resistance of naturally occurring corpora lutea (of the estrous cycle) in swine to the luteolytic action of PGF~ is not due to gonadotropic support from the pituitary.
Theriogenology, 2004
In the present study, the kinetics of the prostaglandin F2a (PGF2a)-metabolite 15-keto-13,14dihydro-PGF2a after a single intramuscular application of various doses of the natural PGF2a dinoprost at Day 7 of the cycle in the mare were investigated. Effects of low doses on estrous cycle length and life span of corpus luteum were examined, because release of PGF2a is still under discussion to have detrimental influence on success rates of transcervical transfer of equine embryos. Eight Shetland pony mares were each randomly assigned to each of four treatments: (a) 0.8 mg/ 100 kg (group T1), (b) 0.4 mg/100 kg (group T2), (c) 0.2 mg/100 kg BM dinoprost i.m. (group T3), and (d) 1 ml physiological saline i.m. (group CO). Treatments were administered as single doses on Day 7 of the estrous cycle. Administration of dinoprost caused dose-dependent rises of plasma concentrations of PGF2a-metabolite, although values of individual mares showed great variation within groups. Prostaglandin treatments resulted in a distinct decrease of plasma progesterone concentrations to values between 1.6 and 7.9 ng/ml within 24 h. Treatment groups had significantly lower progesterone area under the curve (AUC: T1
Effects of prostaglandin E1 (PGE1) on estradiol-17β induced luteolysis in the nonpregnant ewe
Prostaglandins, Leukotrienes and Medicine, 1985
Nonpregnant ewes were assigned as they came into estrus to one of the following randomized treatment groups: 1) Vehicle (1 ml corn oil) + Vehicle (buffer), 2) Estradiol-176 + Vehicle (buffer) or Estradiol-178 + PGEl in buffer. Ewes were unilaterally ovariectomized on day 8 postestrus and an intrauterine cannula was installed in the uterine horn adjacent to the remaining luteal-bearing ovary. Buffer or PGEl (500 ug) in buffer was infused intrauterine every 4 hours from day 8 through day 15. Luteolysis was initiated by giving an intramuscular injection of estradiol-178 (500 pg) on days 9 and 10. Chronic intrauterine infusions of PGEl maintained jugular progesterone through day 15 and weights of corpora lutea and progesterone in corpora lutea on day 15 although luteolysis was initiated by estradiol. It is concluded that chronic intrauterine infusions of PGEl can prevent an estrogen-induced premature luteolysis. 'Journal Series No.2870 the Hawaii Institute of Tropical Agriculture and Human Relources.
Journal of animal science, 1986
Prostaglandin F2 alpha (PGF2 alpha) was injected on d 5, 8 or 11 postestrus in ewes to determine how stage of the estrous cycle would affect PGF2 alpha-induced changes in concentrations of ovarian and pituitary hormones and intervals to the onset of estrus and the preovulatory surge of luteinizing hormone (LH). Initial concentrations of progesterone and average values during the 12 h after PGF2 alpha were related positively to the day of cycle on which PGF2 alpha was administered. Patterns of decline in progesterone after injection of PGF2 alpha were similar among the 3 d. Concentrations of LH in plasma increased in a similar manner from 0 to 12 h in all ewes. After 12 h LH continued to increase, plateaued or declined in ewes treated on d 5, 8 or 11, respectively. Initial concentrations of follicle stimulating hormone (FSH) in plasma were related positively to day of treatment. After treatment with PGF2 alpha, FSH increased within 2 h on d 5 but declined by that time on d 8 or 11. C...
Theriogenology, 1987
Ninety-nine sexually mature, non-pregnant gilts were checked for estrus daily with a mature boar and then allocated at estrus (D 0) to receive 2 kg/d of a diet containing 0, 1, 5 or 10 ppm purified zearalenone between D 5 and 20 of the estrous cycle during two seasons of the year (winter and summer). None of the gilts exhibited any visual signs of "hyperestrogenism" and there was no effect of season on interestrous interval (P > 0.05). A significant effect of zearalenone dose on inter-estrous interval was detected (P < 0.001). Gilts receiving 0 or 1 ppm had similar inter-estrous intervals (21.0 + 0.3 and 21.5 2 0.8 d, respectively) whereas gilts receiving 5 and 10 ppm had extended cycles (29.2 + 2.9 and 32.7 + 3.3 d, respectively). Plasma progesterone concentrations at D 19 to 21 were higher in gilts with extended cycles (P ,< 0.001) and corpora lutea (CL) were present at laparotomy. Some 86% of these retained CL underwent spontaneous regression resulting in the onset of estrus within the next 30 d. Fecal zearalenone concentrations rose during ingestion of contaminated diets and declined to pretreatment values within 2 d (1 ppm) to 8 d (10 ppm) of the cessation of treatment. These data show that feeding zearalenone at concentrations of 5 to 10 ppm from D 5 to 20 of the estrous cycle causes luteal mai.ntenance and extended inter-estrous intervals. Spontaneous regression of these CL usually occurs within 30 d after zearalenone is removed from the diet. Fecal zearalenone analysis does not appear to be an effective method for determining prior exposure to zearalenone when carried out more than a lew days following the last ingestion of zearalenone.
Journal of animal science, 1999
We determined whether a single injection of slow-release estradiol-17beta (SRE2) would induce pseudopregnancy in gilts and whether PGF2alpha would regress the corpora lutea (CL) of pseudopregnancy. Crossbred gilts (n = 40) were induced to ovulate by treatment with 400 IU of hCG + 200 IU of eCG (PG600, Intervet, Millsboro, DE) given at 180 d of age (d = 0). On d 14, gilts were injected i.m. with one of five doses (n = 8 gilts/dose) of SRE2 (0, 12.5, 25, 50, or 100 mg). Blood samples were collected before SRE2 and twice weekly until d 73 to monitor serum progesterone (P4) and estradiol (E2). On d 59, gilts received (i.m.) 10 mg of PGF2alpha (Lutalyse, Pharmacia Upjohn, Kalamazoo, MI) and were checked for estrus for 7 d. On d 62, mammary development was scored (0 = no development; 1 = some development; 2 = teat and gland development) by a neutral observer. Treatment with SRE2 increased (P < .05) peak E2 concentrations, duration of luteal function, and mammary gland score. There were...
Animal Reproduction Science, 2011
The aim of the current study was to determine possible differences in ovarian and pituitary features explaining lower fertility rates in sheep with oestrus induced with intravaginal progestagens or prostaglandin analogues (group FGA and PGF, n = 8 in both) when compared to a control group (group C, n = 8). The growth profiles and the mean individual sizes of preovulatory follicles were similar between groups; however, the number of preovulatory follicles per ewe and, consequently, the number of ovulations were higher in groups FGA and PGF (2.3 ± 0.3 and 2.0 ± 0.1, respectively) than in group C (1.4 ± 0.1, P < 0.05). However, plasma oestradiol concentrations were similar between groups suggesting a defective function in some preovulatory follicles of groups FGA and PGF. In group FGA, the basal LH levels during the follicular phase were lower (0.21 ± 0.0 ng/mL, P < 0.005) than in groups C (0.41 ± 0.1 ng/mL) and PGF (0.55 ± 0.1 ng/mL); the onset of preovulatory discharge being later (21.0 ± 2.3 h vs. 12.8 ± 1.5 in C and 14.5 ± 1.5 in PGF; P < 0.05 for both). Finally, luteal activity was also found to be affected in group FGA; the rate of progesterone secretion per total luteal tissue was lower (range: 0.46-0.65 ng/mL/cm 2 ) than in ewes treated with cloprostenol (2.1-3.3 ng/mL/cm 2 ) and control sheep (2.0-3.4 ng/mL/cm 2 ).