Two hundred fifty four sows Camborough 22 (PIC®), were divided in 3 treatments: T 1 (n=60) - 600 UI of eCG after weaning and 5 mg of LH, after 72 h, with single artificial insemination (AI) (24 h after LH); T 2 (n=95) - same hormonal treatment of T1, with 2 AI (24 and 32 h after LH); T 3 (n=99) - control group, with 3 AI. The averages of weaning-to-estrus interval (WEI) in T1, T2 and T3 were of 87,4 ± 3,0 (87 - 111), 87 ± 0 (87) and 99,9 ± 13,6 (63 - 135) h, respectively, been reduced (P < 0,0001) by gonadotropins. The duration of estrus (DE) were of 44,3 ± 8,78 (12 - 60), 41,3 ± 9,77 (24 - 60) and 60,1 ± 10,22 (36 - 84) h, respectively for T1, T2 and T3, showed lower (P < 0,0001) in treated sows. Fourteen of 155 sows that received gonadotropins (9,03 %) didn't show oestrus. Among these, 10 return to estrus, denote 40% of the total returns. The diferences in LH to ovulation interval (LH-OV) among control group (56,1 ± 15,91, range: 21 - 93 h) and treated groups (35,7 ± 6,07 in T1 and 35,5 ± 6,06 in T2, range: 30 - 42 h) were significant (P < 0,0001). The litter size (LS) were of 10,6 ± 3,25 (2 - 16) in T1, 11,3 ± 3,0 (4 - 20) in T2 and 11,6 ± 2,74 (4 - 18) in T3, while the same demonstred number of piglets born alive (BA) of 9,6 ± 3,14 (2 - 16), 10,5 ± 2,83 (1 - 18) and 10,5 ± 2,73 (4 - 16). In both TL (P = 0,11) and NV (P = 0,06) there weren't any diference. The farrowing rate (FR) in T1, T2 and T3 were, respectively, 76,67 %, 88,42 % and 91,92 %, been diferent between T1 and T3 (P = 0,01). The gonadotropins were effetive in the ovulation induction and synchronization; the use of 2 AI maintained the reproductive index and, however the single AI do not show significance in LS, there is necessity of new reserchs in this area.
Synchronization; Ovulation; Gonadotrophins; Artificial insemination; Sows
