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摘要
The present study investigated the association among serum insulin-like growth factor-I (IGF-I), backfat thickness, and age at first observed estrus in replacement gilts. In total, 80 replacement gilt, Landrace (L, n = 48) and Yorkshire (Y, n = 32), were included. The gilts were determined for age at first observed estrus between 167 to 212 days of age. They were categorized according to age at first observed estrus into %26lt;= 200 days (n = 41) and %26gt; 200 days (n = 36) groups. Backfat thickness, body weight, and serum IGF-I concentration were measured before mating. Age at first mating, interval from boar exposure to first observed estrus, and interval from entry-to-first-mating were recorded. It was found that the level of serum IGF-I negatively correlated with age at first observed estrus (r = -0.26, p = 0.022), as well as with interval from boar exposure to first observed estrus (r = -0.28, p = 0.015), but it positively correlated with backfat thickness (r = 0.37, p %26lt; 0.001). The gilts exhibiting first observed estrus at 5 200 days of age had higher serum IGF-I level (30.2 +/- 1.2 and 25.4 +/- 1.1 nmol/l, p = 0.002) and tended to have a shorter interval from entry-to-first-mating (106.7 +/- 2.8 and 113.2 +/- 2.7 days, p = 0.082) than those exhibiting first estrus at %26gt; 200 days of age. The gilts with backfat %26gt;= 17.0 mm had higher level of serum IGF-I (31.1 +/- 1.1 nmol/l) than those with a backfat of 14.5-16.5 mm (26.2 +/- 1.3nmol/l, p = 0.009) and %26lt;= 14.0 mm (26.0 +/- 1.4 nmol/l, p = 0.008).
- 出版日期2013-3
