TY - JOUR AU - Bennett-Steward, K AU - Cassar, G AU - Plante, C TI - Ovulation induction protocol using equine chorionic gonadotropin and porcine luteinizing hormone in the weaned sow T2 - Journal of Swine Health and Production JF - Journal of Swine Health and Production J2 - JSHAP SN - 1537-209X DP - American Association of Swine Veterinarians PB - American Association of Swine Veterinarians DA - 2007/Jul// PY - 2007 VL - 15 M1 - 4 IS - 4 M2 - 194 SP - 194-197 L2 - https://www.aasv.org/shap/issues/v15n4/v15n4p194.html UR - https://www.aasv.org/shap/abstracts/abstract.php?v15n4p194 L1 - https://www.aasv.org/shap/issues/v15n4/v15n4p194.pdf KW - swine KW - equine chorionic gonadotrophin KW - porcine luteinizing hormone KW - ovulation KW - ultrasound N2 - Objective: To determine the lowest dose of porcine luteinizing hormone (pLH) that induces ovulation in a predictable manner in mixed-parity sows 80 hours after treatment with equine chorionic gonadotropin (eCG) at weaning.Materials and methods: All sows were injected intramuscularly (IM) with 600 IU eCG at weaning. At 80 hours post weaning, sows were treated IM with pLH at doses of 0.625 mg (n = 5), 1.25 mg (n = 14), 2.5 mg (n = 21), and 5.0 mg (n = 5). The 15 controls were untreated. Approximate time of ovulation was determined using transrectal realtime ultrasound 8 hours before and 16 hours post pLH injection, and thereafter at 8-hour intervals until ovulation was confirmed.Results: Administration of pLH was effective in inducing ovulation in weaned sows. The pLH-to-ovulation interval was shorter in sows given pLH at 1.25 mg (P < .05), 2.5 mg (P < .01), and 5.0 mg (P < .05) than in controls. Variance associated with the pLH-to-ovulation interval tended to be less in treated than in control sows (P < .10). More sows administered either 2.5 or 5.0 mg pLH ovulated by 40 hours post pLH administration than all other treatments (P < .01).Implications: Doses of 2.5 and 5.0 mg of pLH did not differ in their effect of inducing ovulation in an estrus-synchronization program initiated with 600 IU of eCG at weaning. Controlling the time of ovulation allows insemination to occur at the time of optimal fertilization. ER -