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Title: COMPARISON OF CIRCULATING CONCENTRATIONS OF REPRODUCTIVE HORMONES IN BOARS OF LINES SELECTED FOR SIZE OF TESTES OR NUMBER OF OVULATIONS AND EMBRYONAL SURVIVAL TO CONCENTRATIONS IN RESPECTIVE CONTROL LINES

Author
item MARISCAL, D - UNIVERSITY OF NEBRASKA
item WOLFE, P - UNIVERSITY OF NEBRASKA
item BERGFELD, E - UNIVERSITY OF NEBRASKA
item CUPP, A - UNIVERSITY OF NEBRASKA
item KOJIMA, FREDDIE - UNIVERSITY OF NEBRASKA
item FIKE, K - UNIVERSITY OF NEBRASKA
item SANCHEZ, T - UNIVERSITY OF NEBRASKA
item WEHRMAN, M - UNIVERSITY OF NEBRASKA
item JOHNSON, R - UNIVERSITY OF NEBRASKA
item Ford, Johny

Submitted to: Journal of Animal Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/22/1996
Publication Date: N/A
Citation: N/A

Interpretive Summary: Follicle stimulating hormone (FSH) is essential for stimulation of ovarian follicular growth. We evaluated concentrations of this hormone in blood of boars from two lines of pigs in which litter size had increased because females were selected for increased ovulation rate. We observed increased FSH concentrations in boars of one of the high ovulating lines relative to an unselected control line, but this difference was not observed in boars of the other high ovulating line. Studies are in progress to explain these divergent findings and to determine if selection for FSH in boars has merit as a means to more rapidly increase ovulation rate in females. JOE FORD IS THE ELEVENTH AUTHOR, R. KITTOK, UNIVERSITY OF NEBRASKA, IS THE TENTH AUTHOR, AND J KINDER, UNIVERSITY OF NEBRASKA, IS THE TWELVETH AUTHOR.

Technical Abstract: The objective was to compare concentrations of gonadotropins and/or gonadal hormones in circulation of boars selected for testis size or ovulation rate and embryo survival to those of respective unselected control lines. In experiments 1 and 2, boars with the greatest estimated paired testis weights (TS) and boars from a control line (C) were used. Concentrations of FSH were similar (P>.10) in males from TS and C lines when they were intact, castrated, after castration and treatment with E2 and during the time boars were under general anesthesia. In experiments 3, 4 and 5, circulating concentrations of FSH, LH, E2 and testosterone (T) during neonatal and pubertal development and in mature boars of lines selected on an index for ovulation rate and embryo survival (I) were compared. Concentrations of E2 were greater in pigs from the I than C line during the early neonatal period but were greater in pigs of the C than I line during pubertal development. Concentrations of FSH were greater (P<.05) in matur boars from the I than C line. In experiment 6, circulating concentrations of T in mature boars from a RL line (cross of Relax Selected and Litter Size lines both selected for high ovulation rate) and boars from a control line (C) were compared. Concentrations of T were greater (P<.05) in boars from the C than RL line. We conclude that selection for testes size does not influence circulating concentrations of FSH. The secretory pattern of E2 in boars before puberty has changed as a result of selection for litter size and ovulation rate and the different patterns of circulating E2 early in life may result in enhanced circulating concentrations of FSH in adult boars as compared to boars of unselected control lines.