EFFECTS OF INJECTION OF GONADOTROPIN-RELEASING HORMONE ON SOW FERTILITY

1989 ◽  
Vol 69 (1) ◽  
pp. 123-129 ◽  
Author(s):  
A. D. GOONERATNE ◽  
R. N. KIRKWOOD ◽  
P. A. THACKER
Keyword(s):  
Reproductive Performance ◽  
Artificial Insemination ◽  
Anterior Pituitary ◽  
Intramuscular Injection ◽  
Follicle Stimulating Hormone ◽  
Gonadotropin Releasing Hormone ◽  
Serum Concentrations ◽  
Releasing Hormone ◽  
Conception Rates ◽  
And Control

A total of 159 Landrace × Yorkshire sows were used to study the effects of an intramuscular injection of gonadotropin-releasing hormone (GnRH) at estrus on reproductive performance. Artificial insemination at 24 h or 24 and 40–44 h following treatment, resulted in similar conception rates for GnRH-treated (77.5 and 69.2%) and control sows (70.0 and 67.5%). Conception rates were not affected by insemination regime. GnRH treatment resulted in slightly improved litter sizes in comparison with control sows (10.45 vs 9.92; P > 0.20) whether inseminated once or twice, but had no effect on piglet weight at birth. Litter size and piglet weight at weaning were also not influenced by treatment. GnRH treatment (100 μg) induced increases in serum concentrations of luteinizing hormone (LH) and follicle stimulating hormone (FSH) from the anterior pituitary within 30 min and maximal serum concentrations were observed 90–120 min postinjection. The induced release of both LH and FSH was of short duration (< 4 h), compared to the natural surge of LH which followed later, coincident with estrus. It was concluded that the overall reproductive performance of sows was not significantly influenced by GnRH treatment immediately prior to estrus. Key words: Sow, GnRH, pituitary response, reproductive performance

15 THE ADMINISTRATION OF GONADOTROPIN-RELEASING HORMONE AROUND THE FIRST POSTPARTUM MONTH INCREASES SUBSEQUENT REPRODUCTIVE PERFORMANCE IN DAIRY COWS

2013 ◽  
Vol 25 (1) ◽  
pp. 154
Author(s):  
J. K. Jeong ◽  
H. G. Kang ◽  
T. Y. Hur ◽  
I. H. Kim
Keyword(s):  
Dairy Cows ◽  
Reproductive Performance ◽  
Development Project ◽  
Management Program ◽  
Gonadotropin Releasing Hormone ◽  
Control Group ◽  
Breeding Period ◽  
Cooperative Research ◽  
Releasing Hormone ◽  
And Control

Early postpartum cyclicity is related to subsequent fertility. This field study evaluated the effect of gonadotropin-releasing hormone (GnRH) administration around the first postpartum month on subsequent reproductive performance in dairy cows. Holstein dairy cows underwent ultrasonography at 30.0 (±6) days postpartum to determine the existence of ovarian structures including corpus lutea (CL), follicles, or cysts. The cows without CL were divided randomly into 2 treatment groups: GnRH group and control group. Cows in the GnRH group received an injection of 100 µg of GnRH (gonadorelin, Godorel, Uni-Biotech Co. Ltd., Korea; n = 151). Cows in the control group received no GnRH (n = 171). Cows diagnosed with endometritis at the time of ultrasonography were excluded from this study. Cows received the normal herd reproductive management program including estrous detection or synchronization, or synchronization of ovulation in the breeding period. The voluntary waiting period from calving to first AI in this study was 40 days. Pregnancy was determined per rectum 60 days after AI by both ultrasonography and palpation. Reproductive performance data were collected for a minimum of 210 days postpartum. Reproduction data between the GnRH and control groups were evaluated by chi-square test or the Cox proportional hazard model with the PHREG procedure using the SAS program (version 9.1, SAS Institute Inc., Cary, NC, USA). The number of days to first insemination after calving did not differ (P > 0.05) between the control group (80.9 ± 2.2 days) and the GnRH group (82.1 ± 2.3 days), while the pregnancy rate to first insemination tended to be higher (P = 0.1) in the GnRH group (42.3%) than in the control group (33.3%). Furthermore, the pregnancy hazard was higher by 210 days in milk for the GnRH group compared with the control group (hazard ratio = 1.33; P < 0.05), which resulted in a 26-day reduction in the median interval to pregnancy. In conclusion, the administration of GnRH around the first postpartum month improved subsequent reproductive performance in dairy cows. This work was carried out with the support of the Cooperative Research Program for Agriculture Science & Technology Development (project no. PJ008464) Rural Development Administration, Republic of Korea.

An unexpected increase in pituitary sensitivity to gonadotropin releasing hormone after treatment with porcine follicular fluid (inhibin) in immature hemicastrate rats

1980 ◽  
Vol 58 (2) ◽  
pp. 220-222 ◽  
Author(s):  
M. Wilkinson ◽  
W. H. Moger ◽  
Liisa K. Selin
Keyword(s):  
Follicular Fluid ◽  
Anterior Pituitary ◽  
Chronic Treatment ◽  
Follicle Stimulating Hormone ◽  
Gonadotropin Releasing Hormone ◽  
Releasing Hormone ◽  
Gonadotrophin Secretion ◽  
Increased Sensitivity ◽  
Gonadotrophin Releasing Hormone ◽  
Lh Secretion

Porcine follicular fluid (PFF) contains a factor (inhibin or folliculostatin) which is reported to selectively inhibit the secretion of follicle-stimulating hormone (FSH) from the anterior pituitary gland. Chronic treatment of hemicastrate immature rats with PFF is able to partially inhibit the FSH-mediated hypertrophy of the remaining testis. However, the pituitaries from PFF-treated rats are paradoxically very sensitive to stimulation with gonadotrophin-releasing hormone (GnRH) and secrete significantly more FSH than control glands. Furthermore, this increased sensitivity results in a large increase in luteinizing hormone (LH) secretion. These observations suggest that under certain circumstances PFF is not selective for FSH and that it surprisingly stimulates rather than inhibits gonadotrophin secretion.

Pituitary and testicular activity in chickens after embryonic testosterone treatment

1983 ◽  
Vol 244 (1) ◽  
pp. E66-E71
Author(s):  
R. L. Taylor ◽  
B. Glick
Keyword(s):  
Luteinizing Hormone ◽  
Pituitary Gland ◽  
Anterior Pituitary ◽  
Testosterone Propionate ◽  
Gonadotropin Releasing Hormone ◽  
Testosterone Treatment ◽  
Releasing Hormone ◽  
Testosterone Levels ◽  
32P Uptake ◽  
And Control

This study was conducted to explain the lower circulating testosterone levels in chickens exposed to testosterone propionate (TP) on the 3rd day of incubation. Control and TP males were injected with either luteinizing hormone (LH) or gonadotropin-releasing hormone (GnRH). Testosterone (T), dihydrotestosterone (DHT), and LH were measured by radioimmunoassay. Levels of circulating T in 20-wk-old TP males were significantly lower than controls, but the response to GnRH was similar in both groups. LH levels were also similar. Testosterone responses to LH in 20-wk-old TP males were lower than controls, possibly due to their lower initial T concentrations. Pituitary extracts from TP and control birds showed similar abilities to induce testicular 32P uptake in day-old cockerels. The data demonstrate that the anterior pituitary gland and testes of TP birds are capable of responding to GnRH and LH, respectively. The TP males are defective in that they fail to produce testosterone, which may reflect a reduced concentration of LH receptors in their testes.

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