HETEROSIS IN REPRODUCTIVE TRAITS OF LANDRACE X LARGE WHITE CROSSBRED SOWS FROM A LOCAL SWINE BREEDING FARM IN THE PHILIPPINES.

Heterosis estimates were determined for reproductive traits using 2,587 litters of 1,256 sows [i.e. 1,088 Landrace (LDR), 1,048 Large White (LRW), 234 F1 cross (LDR x LRW) and 217 reciprocal R1 cross (LRW x LDR)] produced from January 1, 2017 to June 30, 2018 at a local swine breeding farm. Analysis of litter data showed that reproductive traits in crossbred litters were different than in purebred litters in terms of litter size at birth (LSB, +1.05 piglets), litter size at weaning (LSW, +0.87 piglets), piglet weight at birth (BWt) and at weaning (WWt), both -0.05 kg, number of stillbirths (NSB, -0.22 piglets) and number of mummified piglets (NMP, -0.08 piglets). Heterosis estimates were HLSB =0.33%, HLSW =9.58%, HBWt =-3.38%, HWWt =-0.57%, HNSB =-48.31% and HNMP =-31.06%. Using the repeated measures analysis, crossbred sows had lower age at first farrowing (AFF, -4.5 days) and average farrowing interval (AvFInt, -3.8 days), but higher farrowing index (FI, +0.01 litter), average litter size at weaning (AvLSW, +0.91 piglets) and sow productivity index (SPI, +1.65 piglets per sow per year). Heterosis estimates were HAFF =-1.24%, HAvFInt =-2.27%, HFI =0.61%, HAvLSW =10.56% and HSPI =8.06%. [ABSTRACT FROM AUTHOR]