title: Level of nutrition and age at weaning: effects on humoral immunity in young calves.
abstract: Thirty-two calves were studied to determine the effects of level of nutrition (400 and 1000 g (air-dry matter) milk substitute per d) and age at weaning (5, 9 and 13 weeks) on humoral immune responses measured in serum and bronchoalveolar washings (BAW). All calves were immunized with Keyhole limpet haemocyanin (KLH) at 3 weeks of age, and with horse erythrocytes (HRBC) 1 d after weaning. Feeding the higher level of nutrition compared with the lower level decreased anti-HRBC titres and serum IgG2 and IgA responses to KLH (P < 0.05). Weaning at 5 compared with 9 weeks of age decreased serum anti-HRBC responses (P < 0.05), but weaning age had no effect on anti-KLH responses (P > 0.05). Feeding the higher level of nutrition increased total protein (P < 0.05) and IgG2 concentrations (P < 0.01) in BAW. The results showed that variation in husbandry conditions that is within conventional limits affects humoral immune responses in young, artificially-reared calves.
authors.affiliation: Department of Animal Husbandry, University of Liverpool.
authors.forename: J M
authors.initials: JM
authors.lastname: Pollock
authors.forename: T G
authors.initials: TG
authors.lastname: Rowan
authors.forename: J B
authors.initials: JB
authors.lastname: Dixon
authors.forename: S D
authors.initials: SD
authors.lastname: Carter
mesh_terms: D000375:Aging / Q000276:immunology*; D000822:Animal Husbandry; D000818:Animals; D000906:Antibodies / Q000032:analysis; D000917:Antibody Formation; D002417:Cattle / Q000276:immunology*; D004912:Erythrocytes / Q000276:immunology; D005260:Female; D006433:Hemocyanins / Q000276:immunology; D006736:Horses / Q000276:immunology; D007070:Immunoglobulin A / Q000032:analysis; D007074:Immunoglobulin G / Q000032:analysis; D008297:Male; D009752:Nutritional Status; D014886:Weaning
chemical_list: D000906:Antibodies; D007070:Immunoglobulin A; D007074:Immunoglobulin G; D006433:Hemocyanins; C032808:keyhole-limpet hemocyanin