Increasing lambing percentage by androstenedione immunoneutralization in synchronized ewes with or without PMSG

• Published in: Theriogenology Vol. 37; no. 6; pp. 1341 - 1344
• Main Authors: Zafracas, A., Avdi, M., Alifakiotis, T.
• Format: Journal Article
• Language: English
• Published: Elsevier Inc 01.06.1992
• Subjects: ANDROSTENEDIONA; ANDROSTENEDIONE; BREBIS; ewe; EWES; GESTATION MULTIPLE; IMMUNISATION; IMMUNIZATION; immunoneutralization; INMUNIZACION; lambing; LAMBING RATE; LITTER SIZE; MULTIPLE BIRTHS; OESTRUS SYNCHRONIZATION; OVEJA; PARTO; PARTOS MULTIPLES; PARTURITION; PERFORMANCE DE REPRODUCTION; PESO; POIDS; REPRODUCTIVE PERFORMANCE; REPRODUCTIVIDAD; SINCRONIZACION DEL CELO; SYNCHRONISATION DE L'OESTRUS; TAILLE DE LA PORTEE; TAMANO DE LA CAMADA; WEIGHT; androstenedione; immunoneutralization; ewe; lambing
• ISSN: 0093-691X; 1879-3231
• DOI: 10.1016/0093-691X(92)90188-W

The present study was undertaken to determine the potential of active immunization against androstenedione to increase lambing percentage in dairy ewes synchronized with progestagen with or without PMSG. Ewes (n=200) which were milked twice daily by milking machine were alloted randomly to either the immunized or the nonimmunized (control) group. Ewes in the immunized group were given two injections of the immunogen Fecundin (2 ml) 3 wk apart. All ewes were synchronized with intravaginal sponges inpregnated with Cronolone (30 mg); then half of the ewes in each group (Ia and IIa) were given an injection of PMSG (330 IU) on the day of sponge removal. Ewes in groups Ib and IIb did not receive PMSG. Rams were introduced to all ewes the day after sponge removal, which in the immunized groups (Ia and Ib) was 21 after the second injection of Fecundin. The lambing percentage for immunized ewes that were given PMSG was significantly higher than for those not given PMSG (Ia vs Ib, P<0.05), and it was much higher for either of the control groups (nonimmunized, P<0.01). The lamb weight of control ewes was significantly higher than the immunized ewes (P<0.05), while the litter weight of immunized ewes was significantly higher than that of the controls (P<0.05).