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1.
Hormones within the somatotropin cascade influence several physiological traits, including growth and reproduction. Active immunization against growth hormone-releasing factor (GRFi) initiated at 3 or 6 mo of age decreased weight gain, increased deposition of fat, and delayed puberty in heifers. Two experiments were conducted to investigate the effects of GRFi on puberty and subsequent ovulation rate in gilts. Crossbred gilts were actively immunized against GRF-(1-29)-(Gly)2-Cys-NH2 conjugated to human serum albumin (GRFi) or against human serum albumin alone (HSAi). In Exp. 1, gilts were immunized against GRF (n = 12) or HSA (n = 12) at 92 +/- 1 d of age. At 191 d of age, antibody titers against GRF were greater (P < .05) in GRFi (55.5 +/- 1.3%) than in HSAi (.4 +/- 2%) gilts. The GRFi decreased (P < .05) BW (86 +/- 3 vs 104 +/- 3 kg) by 181 d of age and increased (P < .05) backfat depth (15.7 +/- .4 vs 14.8 +/- .4 mm) by 130 d of age. At 181 d of age, GRFi reduced the frequency of ST release (1.0 +/- .5 vs 5.0 +/- .5, peaks/24 h; P < .0001) and decreased (P < .01) ST (1.1 +/- .06 vs 1.7 +/- .06 ng/mL), IGF-I (29 +/- 2 vs 107 +/- 2 ng/mL), and insulin concentrations (3.5 +/- .2 vs 6.3 +/- .2 ng/mL). The GRFi decreased (P < .05) feed conversion efficiency but did not alter age at puberty (GRFi = 199 +/- 5 d vs HSAi = 202 +/- 5 d) or ovulation rate after second estrus (GRFi = 10.7 +/- .4 vs HSAi = 11.8 +/- .5). In Exp. 2, gilts were immunized against GRF (n = 35) or HSA (n = 35) at 35 +/- 1 d of age. The GRFi at 35 d of age did not alter the number of surface follicles or uterine weight between 93 and 102 d of age, but GRFi decreased (P < .05) ovarian weight (.41 +/- .08 vs 1.58 +/- .4 g) and uterine length (17.2 +/- 1.1 vs 25.3 +/- 2.3 cm). Immunization against GRF reduced (P < .05) serum IGF-I (GRFi = 50 +/- 4 vs HSAi = 137 +/- 4 ng/mL) and BW (GRFi = 71 +/- 3 vs HSAi = 105 +/- 3 kg) and increased (P < .05) backfat depth (GRFi = .38 +/- .03 vs HSAi = .25 +/- .02 mm/kg). Age at puberty was similar in GRFi and HSAi gilts, but ovulation rate was lower (P < .05) after third estrus in GRFi (11.3 +/- .8) than in HSAi (13.8 +/- .8) gilts. Thus, GRFi at 92 or 35 d of age decreased serum ST, IGF-I, and BW in prepubertal gilts without altering age of puberty. However, GRFi at 35 d of age, but not 92 d of age, decreased ovulation rate. These results indicate that alterations in the somatotropic axis at 1 mo of age can influence reproductive development in pubertal gilts.  相似文献   

2.
The purpose of this experiment was to determine the ovulation rate after treatment with human chorionic gonadotropin (hCG) in two groups of gilts characterized by different ovarian morphology: grape-type (GT; n = 11) and honeycomb-type (HT; n = 7). At 170 d of age (d 0), gilts were examined by laparoscopy and ovarian type was determined by the distribution of macroscopic follicles present on the ovarian surface. Five to ten minutes after surgery, each gilt received a single injection (i.m.) of 750 IU of hCG. At d 0, GT ovaries had a greater number of large follicles (greater than or equal to 6 mm) than HT ovaries (10.0 +/- .5 vs 2.6 +/- .3; P less than .05), whereas HT ovaries had more small follicles (1 to 3 mm; HT: 42.3 +/- .8 vs GT: 26.7 +/- .9; P less than .05) and total follicles (HT: 59.4 +/- 2.3 vs GT: 52.2 +/- 1.5; P less than .05), although numbers of medium follicles (4 to 5 mm) were similar (GT: 15.6 +/- .8 vs HT: 14.6 +/- 1.7; P greater than .10). Number of induced corpora lutea (CL) per ovary was greater (P less than .05) in gilts with GT ovaries (10.59 +/- 2.9 CL) than in gilts with HT ovaries (5.21 +/- .66 CL). Total weight of luteal tissue (LT) per ovary and serum progesterone concentrations 8 d after induction of ovulation were greater in GT gilts than in HT gilts (GT: 6.37 +/- 1.09 g vs HT: 3.31 +/- .49 g for LT, P less than .05; GT: 21.08 +/- 4.76 ng/ml vs HT: 13.40 +/- 2.05 ng/ml for progesterone, P less than .07).(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   

3.
Two experiments were conducted to determine the effects of pregnant mare's serum gonadotropin (PMSG) on follicular populations and ovulation rates in prepuberal gilts with grape-type (GT) and honeycomb-type (HT) ovaries. The follicular populations were determined at 170 d of age (d 0) and 19 d after PMSG (d 19). In Exp. 1, the mean number of macroscopic follicles of Classes 2 and 3 was greater (P less than .05) in GT (n = 11) than in HT (n = 32) ovaries at d 0, whereas the mean number of those of Class 1 was greater (P less than .05) in HT ovaries. At d 19, no difference was observed between the two ovarian types for any class of follicles. The PMSG-induced ovulation rates were comparable between the two ovarian types (8.3 vs 7.9, GT vs HT, respectively; P greater than .10). In Exp. 2, the microscopic follicular populations were determined on right and left ovaries removed, respectively, on d 0 and 19. At d 0, GT ovaries (n = 5) contained a greater number of Class 5 nonatretic (P less than .01) and atretic (P less than .02) follicles than did HT ovaries (n = 5), whereas at d 19 the mean number was not statistically different between the two ovarian types (P greater than .10). In contrast, gilts with HT ovaries contained a greater (P less than .01) number of Class 4 atretic follicles than gilts with GT ovaries at d 0, whereas at d 19 the mean number was not statistically different between the two ovarian types (P greater than .10).(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   

4.
Changes in follicular development of the ovary at 105, 140 and 175 d of age were observed on 48 prepuberal Yorkshire and Hampshire gilts raised on two planes of nutrition. The follicles from the left ovary were counted and measured by histological techniques. Both the nonatretic and the atretic (more than four pyknotic bodies) antral follicles were classified into six categories according to size, and each category was expressed as percentage of the total number. The proportion of nonatretic follicles belonging to the first category (.19 to .36 mm in diameter) was higher in Hampshire than Yorkshire gilts at d 105 (65.4 vs 47.6%; P less than .05), but not at d 140 and 175. The proportion of atretic follicles to the total number observed was higher in Yorkshire at d 175 than at d 140 and 105 (38.6 vs 21.9 vs 11.6%, respectively; P less than .05), whereas in Hampshire, significant differences were observed only between d 140 and 105 (25.2 vs 3.9%, respectively). The low-plane regimen reduced the percentage of nonatretic follicles of the third (.63 to 1.12 mm) and fourth (1.13 to 2.00 mm) categories in Yorkshire gilts from 14.4 and 7.2% to 9.7 and 4.0%, respectively (P less than .05). According to grouping, size and number of antral follicles, three morphological types of ovaries could be distinguished: honey-comb, grape-like and an intermediate class. Reanalyzing the data accounting for types resulted in radical reduction in the residual variation, hence many significant differences between the two breeds could be identified. At 140 and 175 d of age, Hampshires with honey-comb- and grape-like ovaries had greater numbers of medium and large follicles than Yorkshires (P less than .001). It is concluded that the slower follicular development observed at 105 d of age in Hampshire, as compared with Yorkshire gilts, allows accumulation of greater numbers of antral follicles at 140 and 175 d for both morphological types of ovaries.  相似文献   

5.
This experiment was conducted to compare the ability of USDA porcine FSH-B-1 (pFSH), USDA porcine LH-B-1 (pLH), and pregnant mare's serum gonadotropin (PMSG) to grow large follicles and induce granulosal cell aromatase activity in prepuberal gilts. Twenty-four gilts (164 d old) received one of four treatments by i.m. injection: 1) saline once, n = 8; 2) pFSH (8 micrograms/kg BW, nine times at 8-h intervals), n = 5; 3) pLH (2 micrograms/kg BW, nine times at 8-h intervals), n = 6; or 4) PMSG (15 IU/kg BW, once), n = 5. At slaughter, 72 h after the first injection, the ovaries to saline-treated gilts contained an average of 104 surface antral follicles 1 to 3 mm in diameter. compared to treatment with saline, pFSH increased (P less than .05) the number of follicles 46%, whereas pLH or PMSG decreased (P less than .05) the number by 70 and 84%, respectively. Compared with saline, treatment with PMSG or pLH induced growth of large follicles (7 to 9 mm) (10.8 and 4.8 follicles/gilt, respectively), increased plasma estrogen, increased granulosal cell aromatase activity, and decreased plasma FSH by 51 and 69%; treatment with pFSH had no significant effect on these traits. Results indicate that injected pFSH did not cause growth of large follicles or induce granulosal cell aromatase activity in prepuberal gilts. In contrast, LH initiated growth and increased granulosal cell aromatase activity in a small number of follicles and accelerated atresia among the remaining follicles.  相似文献   

6.
The effect of dietary energy restriction on serum insulin, insulin-like growth factor I (IGF-I), growth hormone, (GH), cortisol, plasma urea nitrogen (PUN) and nonesterified fatty acid (NEFA) concentrations was examined. Angus bulls and steers (10 mo) were allotted to two groups of 12 animals and assigned a treatment order. In a switchback design, animals in order 1 were fed a high grain diet, then fasted, while order 2 animals were fasted, and then fed. Animals were allowed 60 hr to acclimate between treatments. Serum and plasma were obtained at 20 min intervals and 60 min, respectively, for 6 hr after feeding and for the last 6 hr of a 30 hr fast. Serum was assayed for insulin, IGF-I, GH, and cortisol (total and free). Plasma was assayed for PUN and NEFA. Mean insulin (ng/ml) differed between fed (.95 +/- .08) and fasted (.26 +/- .08) animals (P less than 01). Both mean total and free cortisol (ng/ml) were lower in fed (11.48 +/- .99) (1.06 +/- .12) than in fasted (17.10 +/- .93) (1.62 +/- .12) animals, respectively (P less than .01). Animals in order 1 differed in mean IGF-I (ng/ml) between fed (199.0 +/- 8.0) and fasted (116.5 +/- 7.2) treatments (P less than .01). Mean IGF-I for animals in order 2 was 146.7 +/- 7.2 in fed and 213.9 +/- 7.2 in fasted animals (P less than .01). Mean GH did not differ between treatments. Mean PUN and NEFA were higher in fasted than in fed animals (P less than .01). Except for % free cortisol (P less than .05), the hormones did not differ between bulls and steers.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   

7.
To determine breed differences in ovarian function and endocrine secretion, daily rectal ultrasonography was conducted on multiparous lactating Angus (temperate Bos taurus; n = 12), Brahman (tropical Bos indicus; n = 12), and Senepol (tropical Bos taurus; n = 12) cows during an estrous cycle in summer. Blood was collected daily to quantify plasma concentrations of FSH, LH, progesterone, estradiol, GH, insulin-like growth factor (IGF)-I, IGF-II, IGF binding proteins (IGFBP), insulin, glucose, and plasma urea nitrogen (PUN). Numbers of small (2 to 5 mm), medium (6 to 8 mm), and large follicles (> or = 9 mm) were greater (P < .05) in Brahman than in Angus and(or) Senepol cows. Length of the estrous cycle (SEM = .6 d) was similar (P > .10) among Senepol (20.4 d), Angus (19.5 d), and Brahman (19.7 d) cows. Senepol cows had greater (P < .05) diameters of the corpus luteum (CL) and a delayed regression of the CL as compared with Angus cows. The secondary surge of FSH (between d 1 and 2; d 0 = estrus) was greater in Angus than Brahman or Senepol cows (breed x day, P < .05). Between d 2 and 14 of the estrous cycle, concentrations of progesterone, LH, IGF-II, and binding activities of IGFBP-3, IGFBP-2, and the 27- to 29-kDa IGFBP in plasma did not differ (P > .10) among breeds. Concentrations of GH, IGF-I, insulin, and PUN were greater (P < .001) and binding activities of the 22-kDa and 20-kDa IGFBP tended (P < .10) to be greater in plasma of Brahman than in Angus or Senepol cows. Plasma glucose concentrations were greater (P < .05) in Senepol than in Brahman or Angus cows. In conclusion, Brahman (Bos indicus) and Senepol cows (tropical Bos taurus) had greater numbers of follicles in all size categories and greater diameter of CL than Angus (temperate Bos taurus) cows. These ovarian differences may be due to changes in the pattern of secretion of FSH, insulin, IGF-I, and GH but not LH, IGF-II, or IGFBP-2 or -3.  相似文献   

8.
Two experiments were conducted to examine influences of dietary energy and insulin on ovulation rate and patterns of luteinizing hormone (LH), follicle stimulating hormone (FSH), glucose, insulin and estradiol in gilts during 6 d before estrus. In Exp. 1, 36 gilts were given altrenogest for 14 d to synchronize estrus. In a factorial arrangement, gilts were fed one of two levels of dietary energy (5,771 or 9,960 kcal metabolizable energy (ME)/d), and given one of two levels of porcine insulin (0 or .1 IU/kg body weight iv every 6 h). Dietary treatments began 4 d before and insulin treatments began 1 d after the last day of altrenogest, respectively, and lasted until 24 h after estrus. Main effect means for number of corpora lutea were 14.0 +/- 1.3 and 17.6 +/- .9 for 5,771 and 9,960 kcal ME (P less than .05), and 14.6 +/- 1.0 and 17.0 +/- .9 for 0 and .1 IU insulin (P less than .05). Number of LH peaks on d 3 was greater for gilts that received 9,960 kcal than 5,771 kcal (3.3 +/- .2 vs 2.7 +/- .2; P less than .05), and for .1 than 0 IU insulin (3.2 +/- .2 vs 2.7 +/- .2; P less than .05). During the first 24 h of sampling, concentrations of LH and FSH were greater (P less than .05) in gilts receiving 9,960 kcal ME plus insulin than for other treatment combinations. Concentrations of estradiol were not affected by treatments. In Exp. 2, two formulations of insulin were evaluated for influence on ovulation rate. All gilts received altrenogest and 9,960 kcal ME/d as in Exp. 1. Then on the first day after altrenogest, seven gilts each received short-acting insulin (as in Exp. 1), long-acting insulin (zinc suspension, 1.0 IU/kg body weight every 18 to 24 h), or served as controls. Ovulation rates were increased (P less than .05) by both insulin preparations (15.6, control; 19.1, short-acting; 18.5, long-acting; SE = 1.2). Concentrations of LH tended to be greater after short-acting insulin, but differences were not significant (P = .13). We conclude that increases in ovulation rate produced by dietary energy and insulin are not necessarily accompanied by changes in gonadotropins or estradiol.  相似文献   

9.
To investigate some biochemical changes during bovine follicle development, ovaries were obtained from cyclic heifers (7 to 11 heifers/d on each day of the 21-d estrous cycle; N = 152). Follicular fluid from the two largest follicles from both ovaries and a pool from small follicles (N = 30/cow) were collected from each animal and analyzed for ionic, enzymatic and endocrine changes in relation to day of the estrous cycle, follicle size, rank and atretic or growing status. Follicular fluid alkaline phosphatase activity and ascorbate concentrations were highest in all follicular sizes during the earlier portion of the estrous cycle (d 1 to 12; P less than .05), then decreased to the lowest levels (d 13 to 21). As follicular size (diameter) increased lactate dehydrogenase (LDH), acid and alkaline phosphatase activity was reduced in follicular fluid (P less than .05). Alkaline phosphatase and LDH activity tended to be increased in atretic follicles (P less than .10), and was correlated with increased progesterone and androgen concentrations of follicular fluid (r = .4, P less than .05). Both albumin and total protein concentrations decreased as follicular diameter increased (P less than .05). Sodium concentrations in follicular fluid were greater in growing-antral than atretic follicles, and increased with follicular enlargement (P less than .05). Follicular potassium concentrations increased as the estrous cycle progressed (P less than .05), and tended to be elevated in atretic follicles (nonsignificant). Both Ca and Mg concentrations increased with follicular enlargement (P less than .05). Dehydroepiandrosterone and testosterone were the predominant androgens in follicular fluid (androstenedione, the lowest concentration); their concentration decreased with follicle development (P less than .05), but were quite variable. Estradiol was increased in growing follicles (P less than .01). Estrone and estradiol concentrations increased as ovulation approached, particularly in small follicles (less than or equal to 4 mm diameter). Changes of biochemical components found in follicular fluid that relate to the growth and atresia process may provide a more sensitive and accurate method to classify follicle status, and thus aid in understanding the complexity of events associated with maturation of the bovine follicle and oocyte.  相似文献   

10.
Prepubertal gilts of obese (n = 24) or lean (n = 24) genetic lines were injected (s.c.) daily with 0, 2, or 4 mg of porcine somatotropin (pST) for 6 wk starting at 160 d of age to determine whether pST affects follicular function. Blood and ovaries were collected at slaughter 24 h after the last injection. Surface follicles greater than or equal to 1.0 mm in diameter were counted, and pools of follicular fluid (FFL) and granulosa cells were collected from 1.0- to 3.9-mm (small) and 4.0- to 6.9-mm (medium) follicles. Oocytes were collected from small and medium follicles and evaluated for maturational stage and viability. Porcine somatotropin increased (P less than .08) the numbers of small but not the numbers of medium follicles per gilt (P greater than .10). Oocyte maturation and viability were not affected by pST or genetic line. Porcine somatotropin increased (P less than .05) concentrations of insulin-like growth factor I (IGF-I) in serum and FFL of both obese and lean gilts; IGF-I was lower (P less than .01) in lean gilts. Treatment with pST decreased (P less than .05) IGF-II in FFL of lean but not in that of obese gilts. Dose of pST and line had no effect on concentrations of progesterone in FFL of small or medium follicles or on concentrations of estradiol in FFL of small follicles.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   

11.
An experiment was conducted to determine whether morphological and functional characteristics of follicles differed at a similar stage of pubertal (first) and third estrus in the same gilts. Nine prepubertal gilts were checked three times daily for estrus and laparotomized 6 h after detected first and third estrus. Samples of vena cava and ovarian venous blood were collected, follicle numbers and diameters were recorded, and follicular fluid (FF) was aspirated from all follicles 8 to 12 mm in diameter. Sera and(or) FF were analyzed for progesterone (P4), estradiol-17 beta (E2), testosterone (T), androstenedione (A4), 5 alpha-dihydrotestosterone (DHT), plasminogen activator (PA), and plasmin (PLM). Overall mean number of follicles > or = 8 mm in diameter did not differ between gilts at first and third estrus (P > .05) but gilts at first estrus had more follicles 4 to 8 (P < .05) and 8.1 to 10 mm in diameter (P < .01) and fewer 10.1 to 12 mm in diameter (P < .07) than at third estrus. Mean FF concentrations of E2, T, and A4 at third estrus were significantly greater than at first estrus, whereas FF concentrations of P4, DHT, PA, and PLM were similar at first and third estrus (P > .05). Mean concentrations of E2 in systemic and ovarian venous sera were also greater in gilts at third than at first estrus (both P < .05). Systemic concentrations of P4 in gilts at first and third estrus did not differ (P > .05).(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   

12.
The influence of varying doses of human chorionic gonadotropin (hCG) on the preovulatory luteinizing hormone (LH) surge, estradiol-17 beta (E2) and progesterone (P4) was studied in synchronized gilts. Altrenogest (AT) was fed (15 mg X head-1 X d-1) to 24 cyclic gilts for 14 d. Pregnant mares serum gonadotropin (PMSG; 750 IU) was given im on the last day of AT feeding. The gilts were then assigned to one of four groups (n = 6): saline (I), 500 IU hCG (II), 1,000 IU hCG (III) and 1,500 IU hCG (IV). Human chorionic gonadotropin or saline was injected im 72 h after PMSG. No differences in ovulation rate or time from last feeding of AT to occurrence of estrus were observed. All gilts in Groups I and II expressed a preovulatory LH surge compared with only four of six and three of six in Groups III and IV, respectively. All groups treated with hCG showed a rapid drop (P less than .01) in plasma levels of E2 11, 17, 23 h after hCG injection when compared with the control group (35 h). The hCG-treated gilts exhibited elevated P4 concentrations 12 h earlier than the control group (3.1 +/- .5, 3.4 +/- .72, 3.1 +/- .10 ng/ml in groups II, III and IV at 60 h post-hCG vs .9 +/- .08 ng/ml in group I; P less than .05). These studies demonstrate that injections of ovulatory doses of hCG (500 to 1,500 IU) had three distinct effects on events concomitant with occurrence of estrus in gilts: decreased secretion of E2 immediately after hCG administration, failure to observe a preovulatory LH surge in some treated animals and earlier production of P4 by newly developed corpora lutea.  相似文献   

13.
Two different morphological types of ovaries ("grape" and "other" types) previously described by microscopic examination were studied on 107 live gilts. The ovarian type and distribution of macroscopic follicles during the prepuberal period were determined at 140, 160 and 180 d of age by laparoscopic examination. The incidence of grape-type (GT) ovaries was higher (P less than .05) at 140 d of age (50.5%) than at 160 d (38.3%) or 180 d (35.5%). At maturity (d 19 of the first postweaning estrus), 37.7% of the ovaries were classified as GT. The proportion of gilts that maintained their initial type (at 140 d of age) at 160 d, 180 d and at maturity was higher (P less than .05) for the gilts having the other-type (OT) ovaries (49% and 25% for OT and GT, respectively). The mean number of small follicles (1 to 3 mm in diameter) was higher (P less than .05) for the OT ovaries at 140 d (71.5 vs 18.0), at 160 d (79.3 vs 26.2) and at 180 d (77.0 vs 32.8). The number of follicles of 4 to 5 mm was higher (P less than .05) for GT ovaries at 140 d (16.4 vs 4.8), at 160 d (20.9 vs 4.8) and at 180 d of age (21.4 vs 5.7). The large follicles (greater than or equal to 6 mm) were more numerous for the GT at 140 d (7.0 vs .3), at 160 d (5.7 vs .5) and at 180 d (4.4 vs .6). No statistical difference was observed at maturity in the distribution of follicles between the two types.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   

14.
The objectives of this study were to characterize and compare ovarian follicular populations in Gene Pool Control (GPC, randomly selected) and Relax Select line (RS, nine generations of selection for high ovulation rate followed by six generations of random selection) gilts during different stages of the estrous cycle. Thirty-five RS and 23 GPC gilts were allotted randomly within litter for ovary recovery on either d 3, 15 or 19 of the estrous cycle. Surface follicles on the ovaries were classified by size (small, less than 3 mm; medium, 3 to 6.9 mm; large, 7 to 12 mm), and counts were recorded for each ovary. Ovarian weight (OW), number of corpora lutea (CL), follicular fluid volume (FFV) from small, medium and large follicles, residual ovarian weight and follicular fluid weight (FFW) also were recorded. Total numbers of small and medium follicles were greatest on d 15, whereas total number of large follicles and FFW were greatest on d 19. The OW, FFW and follicle numbers of all classes were lowest on d 3. The RS gilts expressed longer interestrous intervals (21.9 vs 20.4 d, P less than .05) and higher ovulation rates (18.5 vs 15.3 CL, P less than .01) than GPC gilts. The left ovary of RS gilts was responsible for most of the ovulation rate advantage (10.3 vs 7.4 CL, P less than .01) Overall, GPC gilts had more total small follicles than RS gilts (P less than .01). The advantage was due primarily to higher numbers of small follicles at d 15.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   

15.
A study was done to test whether ovulatory follicles destined to form subfunctional corpora lutea differed from normal ovulatory follicles in steroidogenic function. Twenty-five ewes were treated with prostaglandin F2 alpha on d 11 of the estrous cycle, then unilaterally ovariectomized before (n = 13) or after (n = 12) the surge of luteinizing hormone (LH) at the induced estrus to collect "control" follicles, which would have produced normal corpora lutea. In 15 ewes, the second ovary was removed 63 to 84 h later to collect "treated" follicles before (n = 7) or after (n = 8) the second expected surge of LH. Five ewes (control) were allowed to ovulate from the remaining ovary at first estrus and another five (treated) at the second estrus (3 to 4 d later). Treated ewes had lower serum progesterone than control ewes during the ensuing cycle (P less than .05). Treated follicles contained less estradiol in the theca (4.4 +/- .6 vs 10.0 +/- 2.5 ng; P less than .05), less androstenedione (.1 +/- .1 vs 1.0 +/- .2 ng) and estradiol (.5 +/- .1 vs 2.9 +/- 2.2 ng) in the granulosa (P less than .05) and less progesterone in the follicular fluid (.8 +/- .4 vs 3.3 +/- .8 ng; P less than .05) than control follicles, when removed before the surge of LH. Follicles removed after the surge of LH did not differ. In conclusion, ovulatory follicles with low steroidogenic function became corpora lutea that secreted lower-than-normal quantities of progesterone.  相似文献   

16.
A population of ovarian follicles was studied in 32 gilts with two morphological types at four physiological stages. Left ovaries were serially sectioned (10 microns), and follicles (greater than .19 mm) were counted and measured by histological technique. In Exp. 1, prepuberal gilts that maintained the grape-type (GT) or other-type (OT) of ovaries at 140 and 160 d of age as determined by laparoscopy had their population of follicles studied at 165 d of age and compared with that on d 3 of the first puberal estrus in gilts that maintained the same ovarian type (GT or OT) at 140, 160 and 180 d of age. In Exp. 2, gilts that maintained the same ovarian types at 140, 160 and 180 d of age were compared at d 19 and 3 of the first and second puberal estrus, respectively. At 165 d of age, OT ovaries contained a greater number of classes 3 (.63 to 1.12 mm) and 4 (1.13 to 2.00 mm) nonatretic (less than 4 pycnotic bodies) follicles than GT (P less than .01), whereas at d 3 of the first puberal estrus, their mean number became comparable between the two ovarian types (P greater than .1) and similar to 165-d GT ovaries. At 165 d of age, atretic follicles formed 19.6% and 10.7% of the population of antral follicles in OT and GT ovaries (P less than .05) whereas at puberty 17.5% and 19.6% atresia was observed in the same two groups, respectively (P greater than .10).(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   

17.
The objective of this study was to determine if alterations in dietary intake of heifers can influence IGF-I concentrations in plasma and(or) follicular fluid (FFL), size of follicles, and steroid concentrations in FFL (as an indicator of steroidogenic capacity). Cyclic heifers [n = 23; mean +/- SE body weight (BW) = 373 +/- 7 kg] were individually fed for 10 weeks either: a) 1.8% of BW in dry matter (DM) per d (GAIN; n = 7), b) 1.1% of BW in DM per d (MAINT; n = 8) or c) 0.7% of BW in DM per d (LOSE; n = 8). After 10 wk of treatment, heifers were ovariectomized 36-40 hr after the second injection of prostaglandin F2 alpha analog (2 injections 11 d apart), and plasma and ovaries were collected. Heifers weighed 444 +/- 13,387 +/- 8 and 349 +/- 9 kg in the GAIN, MAINT and LOSE groups, respectively, at time of ovariectomy. Mean diameter of follicles greater than or equal to 10 mm was greater (P less than .05) for GAIN (15.6 mm) than for MAINT (11.0 mm) or LOSE (12.5 mm) heifers. Numbers of follicles and concentrations of IGF-I in plasma and FFL did not differ (P greater than .20) between LOSE, MAINT and GAIN heifers. Progesterone concentrations were greater (P less than .05) in small and medium follicles of GAIN than MAINT or LOSE heifers, but were unaffected by diet in large follicles. Estradiol concentrations in FFL in small, medium and large follicles were unaffected (P greater than .20) by dietary treatment.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   

18.
The effect of a new group housing system on performance (132 gilts and litters) and endocrinological (35 gilts) and immunological functions (28 gilts) was studied. Animals were randomly assigned to a conventional system (control), involving greater than 2 mo in individual stalls, or to the Hurnik-Morris (H-M) housing system, involving continuous housing in small groups, for breeding-gestating swine. The gilts were reared throughout gestation in their respective housing systems and moved 3 to 5 d prefarrowing to a common farrowing facility. Various production data were collected, including sow weight and backfat measurements, number of pigs born, number born alive, number weaned, litter birth weight, and litter weaning weight. An adrenal function test using dexamethasone pretreatment and ACTH1-24 challenge was imposed on gilts 5 d prebreeding and once between d 81 to 87 of gestation. Plasma progesterone was measured at the same time. Immune function was measured by serum antibody response to hen egg white lysozyme (HEWL) and delayed-type hypersensitivity (DTH) to tuberculin. Gilts reared in the H-M housing system exhibited a number of pigs weaned per litter and litter weaning weights comparable to the number and weights in the control system (7.3 +/- .33 vs 6.9 +/- .38, P = .421 and 56.9 +/- 2.42 kg vs 51.3 +/- 2.76 kg, P = .132, respectively). Prefarrowing and weaning backfat measurements were significantly reduced in group-housed gilts (15.8 +/- .45 mm vs 17.8 +/- .55 mm, P = .005 and 14.6 +/- .4 mm vs 16.2 +/- .42 mm, P = .008, respectively).(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   

19.
To determine whether long-term administration of growth hormone (GH)-releasing factor (GRF) and(or) thyrotropin-releasing hormone (TRH) alters ovarian follicular fluid (FFL) concentrations of insulin-like growth factor-I (IGF-I), progesterone, and estradiol (E2), and follicular growth, Friesian x Hereford heifers (n = 47; 346 +/- 3 kg) were divided into the following four groups: control (vehicle; n = 11); 1 micrograms GRF (human [Des NH2 Tyr1, D-Ala2, Ala15] GRF [1-29]-NH2).kg-1 BW.d-1 (n = 12); 1 microgram TRH.kg-1 BW.d-1 (n = 12); or GRF + TRH (n = 12). Daily injections (s.c.) continued for 86 d. On d 89, heifers that had been synchronized were slaughtered and ovaries were removed. Follicles were grouped by magnitude of diameter into the three following sizes: 1 to 3.9 mm (small, n = 55), 4.0 to 7.9 mm (medium, n = 63), and greater than or equal to 8 mm (large, n = 71). Growth hormone-releasing factor and(or) TRH did not affect (P greater than .10) IGF-I concentrations in FFL of any follicle size group. Growth hormone-releasing factor increased (P less than .06) size (means +/- pooled SE) of large follicles (14.7 vs 13.0 +/- .6 mm). Growth hormone-releasing factor also increased (P less than .05) progesterone concentrations 4.4-fold above controls in FFL of medium-sized follicles but had no effect on progesterone in FFL of the small or large follicles. Thyrotropin-releasing hormone did not alter FFL progesterone or E2 concentrations in any follicle size group. We conclude that the GRF and(or) TRH treatments we employed did not affect intra-ovarian IGF-I concentrations, but GRF may alter steroidogenesis of medium-sized follicles and growth of large follicles.  相似文献   

20.
Gilts bred at first (n = 18) and third (n = 18) estrus were assigned in replicates of equal numbers to be slaughtered on d 3, 15 and 30 post-mating to assess fertilization rate, embryonic losses and serum concentrations of estrogen (estradiol-17 beta + estrone) and progesterone. Mean number of ovulations was lower among gilts bred at first vs third estrus (12.2 vs 14.5; P less than .05), with no difference in fertilization rate (100 vs 98%). Embryonic survival was lower (P less than .05) among gilts bred at first vs third estrus on d 15 (78.1 vs 95.4%) and 30 (66.7 vs 89.4%) of gestation. Serum estrogen (pg/ml) and progesterone (ng/ml) levels, although lower in gilts bred at first vs third estrus, were not significantly different at the three stages of gestation studied. The ratio of progesterone to estrogen in gilts bred at first estrus was higher than in those bred at third estrus on d 15 (439 +/- 71 vs 210 +/- 17) and 30 (597 +/- 106 vs 179 +/- 50), but was lower on d 3 (187 +/- 37 vs 444 +/- 123; stage of gestation X estrous period interaction, P less than .05). These data suggest that changes in the ratio of systemic levels of estrogen and progesterone may be related to early embryonic mortality in gilts bred at pubertal estrus.  相似文献   

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