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Prepuberal gilts were injected with PMSG to determine whether expression of a bovine growth hormone (bGH) transgene inhibited preovulatory maturation of ovarian follicles. Seven transgenic (TG) gilts of line 3706, which expresses a mouse metallothionein-bGH transgene, and eight nontransgenic, control (C) gilts (128 to 147 d old) were injected with PMSG, 12.5 IU/kg BW, 72 h before necropsy. Surface ovarian follicles > or = 1 mm in diameter were counted, measured for diameter, and aspirated for fluid. Follicles were classified morphologically as healthy or atretic and those with follicular fluid estradiol-17 beta > or = 100 ng/mL were classified as estrogenactive (EA). The number of follicles per gilt was 64.3 +/- 6.1 (mean +/- SEM) and did not differ significantly between bGH-TG and C gilts. The PMSG treatment induced growth of large (> 5 mm) follicles in both bGH-TG and C gilts. However, compared with C gilts, bGH-TG gilts had fewer (P < .05) large follicles (5.9 +/- 1.5 vs 18.3 +/- 5.4), a lower proportion of EA large follicles (35 +/- 12.5 vs 69 +/- 13.2%), and in large follicles less (P < .05) estradiol-17 beta (86 +/- 17 vs 350 +/- 69 ng/mL) and androstenedione (300 +/- 33 vs 1,283 +/- 221 ng/mL). Follicular fluid progesterone and inhibin did not differ significantly between bGH-TG and C gilts. The incidence of atresia among small and medium follicles did not differ significantly between bGH-TG and C gilts.(ABSTRACT TRUNCATED AT 250 WORDS)

Ovulation time of gilts was controlled by oral treatment with altrenogest (17-allyl-hydroxyestra-4,9,11-trien-3-one) followed by gonadotropic hormone injections. Gilts were laparotomized 42 to 44 h after injection of human chorionic gonadotropin. Spermatozoa were surgically placed into ligated oviducts of gilts after one of the following semen treatments: frozen and thawed in Beltsville thawing solution (F-BTS) or in seminal plasma (F-SP); unfrozen, processed like the frozen semen, but not cooled, frozen or thawed, and extended in Beltsville thawing solution (U-BTS) or in seminal plasma (U-SP). Ova were recovered 5 or 24 h after insemination and their stage of development was determined. At 5 h, F-BTS and U-BTS spermatozoa had fertilized significantly more ova (45 and 69%, respectively) than the F-SP and U-SP spermatozoa (5 and 34%, respectively). Ova fertilized by F-BTS and U-BTS spermatozoa had reached a more advanced stage of development than ova fertilized by F-SP and U-SP spermatozoa at both recovery times. Unfrozen spermatozoa (U-BTS or U-SP) fertilized more ova by 5 h after tubal deposition than F-BTS or F-SP spermatozoa (P less than .005 for each comparison). By 24 h, the percentage of fertilized ova was similar for all treatments. The results indicate that semen processing reduced capacitation time of boar spermatozoa to an extent similar to passage through the uterus. The capacitation time of frozen-thawed spermatozoa appeared to be similar to spermatozoa that were processed, but not cooled, frozen or thawed.