Author : Somchai Orankanok

Summary : Data on representative performance were collected from two farms in the Philippines: Farm A and Farm B. From Farm A, data from 6,927 litters farrowed by purebred Landrace (L) and Yorkshire (Y) and reciprocal crossed (LY, YL) sows inJanuary 1989 - December 1991 were used. These litters were classified into 14 breed-groups. From Farm B, data from 5,608 litters farrowed by purebred Landrace and Yorkshire and reciprocal crossed (LY, YL) sows in January 1988 - December 1991, which were classified into 10 breed-groups, were used. Data on production performance were obtained from 20 D (LY) barrows, 20 D (LY) gilts, 20 D (YL) barrows and 20 D (YL) gilts and 40 gilts each from purebred Landrace and Yorkshire. The Least-square Technique was used in data analysis. In Farm A, breed-group, breed of dam, litter order, and month and year of farrowing had significant effects on most of the important traits associated with sow productivity. Crossbred (LY, YL) sows had better litter size at birth and at weaning, litter weight at weaning, and number of pigs weaned per sow per year than purebred sows. Within purebred litters and litters farrowed by crossbred sows, no significant difference was found in most of these traits. Most reproductive traits from the first two litter orders were significantly lower than the subsequent litter order. Sire effects on most reproductive traits were small and insignificant although the Duroc and Pietrain-Duroc boars sired slightly more pigs weaned per sow per year than either the Landrace or Yorkshire boars. In Farm B, breed-group, breed of dam, litter order, and month and year of farrowing had significant effects on most traits associated with sow productivity. The purebred Landrace litters were significantly bigger and heavier at weaning and the Landrace litters had longer farrowing interval and lower sow index than purebred Yorkshire litters. Among the litters farrowed by corssbred (LY, YL) sows, most reproductive traits were not significantly different. The breed of dam showed that crossbred sows had bigger litter size at weaning, higher survival rate from birth to weaning, shorter farrowing interval, higher sow index, and more number of pigs weaned per sow per year than purebred sows. Sire effects on some traits were significant. Landrace boars produced pigs with higher survival rate, heavier pigs and litters at weaning but had longer weaning to conception interval and farrowing interval than the Yorkshire boars. The Duroc boars sired significantly more pigs weaned per sow per year than either the Yorkshire or Landrace boars. In Farm A, the Landrace x Yorkshire sows were 6.18 percent, 5.85 percent, 8.07 percent, and 7.99 percent bigger for litter size born alive, litter size at birth, litter size at weaning and pigs weaned per sow per year, respectively. There were no significant differences between the two groups of market hogs, D (LY) and D (YL), in terms of average daily gain, average daily gain from birth, body weight at 180-day, backfat thickness and feed efficiency with the grand average of 787 g, 594 g, 106.94 kg, 1.41 cm, and 3.10, respectively.