|Lamberson, W. - UNIVERSITY OF MISSOURI|
|Sterle, J. - UNIVERSITY OF MISSOURI|
|Safranski, T. - UNIVERSITY OF MISSOURI|
Submitted to: Journal of Animal Science Supplement
Publication Type: Abstract Only
Publication Acceptance Date: July 28, 1995
Publication Date: N/A
Technical Abstract: Insulin-like growth factor II (IGF-II) is a peptide hormone which is involved in metabolic regulation of growth. The objective of this study was to determine if IGF-II concentration was predictive of growth, compositional and reproductive traits of pigs. Forty intact male and 60 female pigs divided equally between modified open front or complete confinement finishing facilities were bled at 9 and 21 wk of age. IGF-I, IGF-II and growth hormone (GH) concentrations were determined via RIA. Pigs were weighed at each sampling date. Backfat and loin eye area were measured with real-time ultrasonography and adjusted to 100 kg. Age at puberty and first parity litter size were measured on gilts. Blood was collected from a random sample of 52 progeny from 13 litters at 9 wk of age and assayed for IGF-II. IGF-II concentrations were greater at 9 than 21 wk of age (226.7 vs 159.3 ng/ml, respectively; P<.001), but did not differ significantly between sexes. The correlation between IGF-II concentration assayed from samples collected at 9 and 21 wk was .08. The similar correlation for IGF-I was .28. The partial correlations between IGF-I and IGF-II concentrations were .33 and .14 at 9 and 21 wk, respectively. The partial correlation between IGF-II and GH at 9 wk was -.07. The heritability of IGF-II concentration was .08. The regression of weight at 9 wk on IGF-II concentration was .026 kg/ng (P< .001). IGF-II concentration did not significantly affect backfat thickness, loin eye area, percentage lean, days to 100 kg, weight at 21 wk, age at puberty or litter size. IGF-II was positively related to weight early in life, but not to growth, compositional or reproductive traits expressed by the finishing or adult pig.