The Thai Journal of Veterinary Medicine
Association among Serum Insulin–like Growth Factor–I, Backfat Thickness, and Age at First Observed Estrus in Gilts
The present study investigated the association among serum insulin-like growth factor-I (IGF-I), backfatthickness, and age at first observed estrus in replacement gilts. In total, 80 replacement gilt, Landrace (L, n = 48) andYorkshire (Y, n = 32), were included. The gilts were determined for age at first observed estrus between 167 to 212days of age. They were categorized according to age at first observed estrus into ≤ 200 days (n = 41) and > 200 days (n= 36) groups. Backfat thickness, body weight, and serum IGF–I concentration were measured before mating. Age atfirst mating, interval from boar exposure to first observed estrus, and interval from entry-to-first-mating wererecorded. 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 positivelycorrelated with backfat thickness (r = 0.37, p < 0.001). The gilts exhibiting first observed estrus at ≤ 200 days of age hadhigher 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-tofirst-mating (106.7±2.8 and 113.2±2.7 days, p = 0.082) than those exhibiting first estrus at > 200 days of age. The giltswith backfat ≥ 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 ≤ 14.0 mm (26.0±1.4 nmol/l, p = 0.008).
Faculty of Veterinary Science, Chulalongkorn University
Roongsitthichai, Atthaporn; Koonjaenak, Seri; and Tummaruk, Padet
"Association among Serum Insulin–like Growth Factor–I, Backfat Thickness, and Age at First Observed Estrus in Gilts,"
The Thai Journal of Veterinary Medicine: Vol. 43:
1, Article 15.
Available at: https://digital.car.chula.ac.th/tjvm/vol43/iss1/15