title: Lactational variation and relationship to postnatal growth of insulin-like growth factor-I in mammary secretions from genetically diverse sows.
abstract: Mammary secretions obtained from four groups of sows at parturition and on days 7, 14 and 21 of lactation were defatted and assayed for total protein and insulin-like growth factor-I (IGF-I). Sows (n = 57) represented two breeds (Landrace and Duroc) and two genetic lines (selected for differences in sow productivity index, SPI) within each breed. Colostrum of Duroc sows was 4-6 fold and 30-60 fold greater in protein (P less than .001) and IGF-I (P less than .001) concentrations, respectively, than the corresponding day 7 milk from these sows. In contrast, the colostrum of Landrace sows was 2-3 fold and 30-50 fold greater in protein (P less than .001) and IGF-I (P less than .001) concentrations, respectively, than the corresponding day 7 milk. The IGF-I content in milk from Duroc sows did not differ among days 7, 14 and 21 of lactation, whereas the IGF-I content of day 7 milk from Landrace sows exceeded those for the corresponding 14 day and 21 day secretion (P less than .05). IGF-I concentration in days 14 and 21 milk was higher in Duroc (P less than .001 respectively) than Landrace sows. No significant differences in total protein or IGF-I content of mammary secretions were observed between the selected and control lines within each breed.(ABSTRACT TRUNCATED AT 250 WORDS)
authors.affiliation: Laboratory of Molecular Biology, Ohio Agricultural Research and Development Center, Ohio State University, Wooster 44691-6900.
authors.forename: F A
authors.initials: FA
authors.lastname: Simmen
authors.forename: K Y
authors.initials: KY
authors.lastname: Whang
authors.forename: R C
authors.initials: RC
authors.lastname: Simmen
authors.forename: G A
authors.initials: GA
authors.lastname: Peterson
authors.forename: M D
authors.initials: MD
authors.lastname: Bishop
authors.forename: K M
authors.initials: KM
authors.lastname: Irvin
mesh_terms: D000818:Animals; D000833:Animals, Suckling / Q000254:growth & development*; D001947:Breeding; D003126:Colostrum / Q000032:analysis; D005260:Female; D005838:Genotype; D007334:Insulin-Like Growth Factor I / Q000032:analysis / Q000378:metabolism*; D007774:Lactation / Q000235:genetics / Q000378:metabolism*; D008321:Mammary Glands, Animal / Q000378:metabolism*; D008892:Milk / Q000032:analysis; D008894:Milk Proteins / Q000032:analysis; D011247:Pregnancy; D013002:Somatomedins / Q000378:metabolism*; D013552:Swine / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*
chemical_list: D008894:Milk Proteins; D013002:Somatomedins; D007334:Insulin-Like Growth Factor I