|Zimmerman, D - UNIVERSITY OF NEBRASKA|
Submitted to: Journal of Animal Science Supplement
Publication Type: Abstract Only
Publication Acceptance Date: February 15, 2001
Publication Date: June 20, 2001
Citation: Ford, J.J., Zimmerman, D.R., Wise, T.H., Leymaster, K.A., Christenson, R.K. 2001. Selection for greater number of corpora lutea in gilts increased plasma follicle-stimulating hormone concentrations in prepubertal development [abstract]. Journal of Animal Science. 79 (Supplement 2):90. (Abstract #259) Technical Abstract: Secretion of follicle-stimulating hormone (FSH) was evaluated in gilts from two studies in which ovulation rate increased through direct selection for number of corpora lutea (CL). Plasma FSH concentrations were greater (P<0.05) at 53 and 75 d of age in selected compared to control gilts of the University of Nebraska gene pool lines. Likewise, plasma FSH on d 34, 55, and 85 was greater (P<0.05), relative to controls, in gilts of White Composite lines selected for either increased ovulation rate or for greater uterine capacity. Unilateral ovariectomy and hysterectomy were conducted at 160 d of age on random gilts in these 3 lines. Ovarian and uterine wt were less (P<0.01) in the control than in the ovulation rate line. Subsequently, ovulation rate was determined during pregnancy. Controls had fewer (P<0.01) CL than gilts of the ovulation rate line but similar (P>0.10) numbers to gilts of the uterine capacity line. Plasma FSH on d 85 correlated positively with subsequent ovulation rate within each line. Ovarian wt at 160 d of age also correlated with subsequent ovulation rate in control and ovulation rate gilts but not in uterine capacity gilts. Gilts selected for increased number of CL, in two independent studies, had greater concentrations of FSH during prepubertal development than respective controls. The modest but significant, positive association of FSH at 85 d of age with subsequent ovulation rate provides additional support for using plasma FSH in prepubertal gilts to indirectly select for ovulation rate.