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ARS Home » Plains Area » Clay Center, Nebraska » U.S. Meat Animal Research Center » Livestock Bio-Systems » Research » Publications at this Location » Publication #127540
Title: FAILURE OF ENDOGENOUS FOLLICLE-STIMULATING HORMONE (FSH) TO STIMULATE EARLY OVARIAN GROWTH IN PREPUBERTAL GILTS

Author
item Ford, Johny
item Wise, Thomas
item Christenson, Ronald

Submitted to: Journal of Animal Science Supplement
Publication Type: Abstract Only
Publication Acceptance Date: 1/30/2002
Publication Date: 6/20/2002
Citation: Ford, J.J., Wise, T.H., Christenson, R.K. 2002. Failure of endogenous follicle-stimulating hormone (FSH) to stimulate early ovarian growth in prepubertal gilts [abstract]. Journal of Animal Science. 80 (Supplement 2):83. (Abstract #207)

Interpretive Summary:

Technical Abstract: Prepubertal gilts of three genetic lines selected for increased ovulation rate have greater plasma FSH concentrations (10 - 25%) than observed in gilts of respective control lines (Cassady et al., 2000; Ford et al., 2001). The objective of the current study was to determine if ovarian weights at 85 d of age were influenced by endogenous FSH. Gilts from a line eselected for greater number of corpora lutea (OR, n = 137) and from the control line (CO, n = 138) were bled at 65 and 75 d of age. At 85 d of age, blood samples were collected followed by high lumbar laparotomy and removal of one ovary. The study was conducted in spring and fall seasons. Body weight was greater (P < 0.05) in CO than in OR gilts at 56 and 154 d of age. Plasma FSH concentrations, determined by radioimmunoassay, were 19% greater (P < 0.001) at 65 d of age and 13% greater (P < 0.001) at 75 d of age in OR than in CO gilts. Ovarian weight (range 0.05 - 2.34 g) was slightly heavier (P < 0.09) on the left than on the right side (0.68 vs 0.40 g). Plasma FSH concentrations at 85 d (3.6 vs 3.7 ng/mL) and ovarian weight (0.47 vs 0.46 g) were similar in CO and OR gilts, respectively, but ovarian weight was correlated negatively with plasma FSH concentration (r = -0.29, P < 0.01). For gilts in the first season, pubertal age was similar (P > 0.5; 206 vs 203 d) in the two lines; luteal phase ovarian weight adjusted for number of corpora lutea was heavier (P < 0.05) in OR than in CO gilts. FSH concentration and negative correlation of FSH with ovarian weight indicate that negative feedback control of FSH secretion by the ovaries is operative at 85 d of age in both lines. In addition, ovarian weight prior to 85 d of age is not stimulated by the greater circulating FSH in OR gilts observed on d 65 and 75.