Factors affecting age at first mating if gilts in purebred commercial herds in Thailand
1997
Nalinee Imboonta | Chancharat Reodecha | J.T. Yu, Thomas (Chulalongkorn Univ., Bangkok (Thailand). Faculty of Veterinary Science. Dept. of Animal Husbandry)
Performance test and reproductive records of Landrace, Yorkshire and Duroc gilt from 4 commercial farms collected from 1992 to 1996 were used in this study. The number of gilt records after editing was 5,305. Least-squares procedures were used to determine the effect of herd-year-season (HYS), breed (B), backfat (BF), ayerage daily gain (ADG) and lion eye area (LEA) on age at first mating (AGE). HYS, B, BF, and ADG significantly affected the age at first mating (p0.01). Gilts were categorized by backfat depth into three groups of 1.2 cm; 1.2-2.0 cm; and 2.0 cm, as 1st, 2nd and 3rd group respectively. Phenotypic correlation between AGE and BF were -0.14, -0.14 and -0.09 for pooled data, 1st and 2nd group, respectively (p0.01). No correlation was found in the 3rd group. Results indicated that AGE was affected by HYS and B the gilts with 2.0 cm backfat showed negative correlation between BF and AGE.
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