Ovarian response, embryo recovery and results of embryo transfer in a Hungarian native pig breed

The objective of the study was to use embryo transfer (ET) for propagation of the Swallow Belly Mangalica population. Mangalica is a native Hungarian pig breed adapted to extreme climate and housing conditions and distinguish ed for excellent meat and fat quality. However, due to their weak reproduct ive characteristics and relatively high fat proportion, Mangalica pigs have been replaced by modem breeds. Now, there is an increased interest again t o safeguard the properties of this breed. We conducted two experiments. Fir st, we used a total of 18 puberal Mangalica gilts to determine an optimal s uperovulatory treatment. Following estrus synchronization with Regumate(R), we injected gilts with either 750, 1000 or 1250 IU PMSG, followed by 750 I U hCG 80 h later. We scanned ovaries endoscopically 3 days after hCG admini stration. The application of 1000 and 1250 IU PMSG resulted in a higher rat e of ovulation compared to 750 IU (24.2 +/- 3.6 and 21.0 +/- 2.3 vs. 13.7 /- 2.7 P<0.05). The number of follicular cysts increased after administrati on of 1250 IU PMSG compared to 750 and 1000 IU (2.0 +/- 1.3 vs. 0.3 +/- 0.7 and 0.2 +/- 0.3, P<0.05). Thus, we chose 1000 IU PMSG for further stimulat ion of Mangalica gilts. In the second experiment, we induced superovulation in 10 Mangalica donor gilts by 1000 IU PMSG and 750 IU hCG. Gilts were fix ed-time inseminated, and then five days later embryo collection was carried out surgically (n=6) or endoscopically (n=4). Out of the 187 ova recovered , 92.5% were at the morula/blastoeyst stage. The embryo recovery rate was h igher following surgical flushing than following endoscopy (91.5 +/- 4.4% v s. 71.4 +/- 12.7%, P<0.05). Altogether 143 embryos were transferred surgica lly or endoscopically into 8 Landrace recipients. Surgical and endoscopic t ransfer of Mangalica embryos into Landrace gilts resulted in pregnancies in 3 and 2 gilts, respectively; thus the overall farrowing rate was 62.5%. Th e birth of 59 Mangalica piglets from 5 embryo recipients equals an average litter size of 11.8 +/- 1.3, which is two times larger than usual in this b reed. Therefore, we concluded that an appropriate inter-breed ET program is a suitable tool to propagate the endangered Mangalica breed. (C) 2001 by E lsevier Science Inc.