title: Feed intake, body weight, body condition score, musculation, and immunocompetence in aged mares given equine somatotropin.
abstract: Sixteen 20- to 26-yr-old mares were given 0, 6.25, or 12.5 mg/d equine somatotropin (eST) to determine whether aged mares respond to ST with changes in feed intake, body weight, body condition score (based mostly on fat cover), or immunocompetence. Neither dry matter intake, body weight, nor body condition scores were altered during the 6 wk of eST injection. However, based on photographs taken to evaluate musculation before and after treatment (scores 0 to 4), mares given eST developed greater (P < .07) muscle definition (1.8 +/- .6 and 2.5 +/- .6 for 6.25 and 12.5 mg eST/d, respectively) than control mares (.7 +/- .4). Total circulating leukocytes increased (P < .05) in both of the eST-treated groups during the 6-wk injection period, caused by an increase (P < .05) in granulocytes. Lymphocyte numbers were not altered. Granulocyte oxidative burst activity was not altered by eST treatment. Although lymphocyte proliferative responses to phytohemagglutinin, pokeweed mitogen, or lipopolysaccharide were not altered during the treatment period, lymphocyte proliferation in response to phytohemagglutinin and pokeweed mitogen increased twofold in eST-treated horses at 2 wk after eST treatment. In overview, the increased musculation and the increase in granulocyte numbers in mares given eST suggest that eST supplementation may improve the health and well-being of aged mares.
authors.affiliation: Department of Animal Science, Rutgers, State University of New Jersey, New Brunswick 08903, USA.
authors.forename: K
authors.initials: K
authors.lastname: Malinowski
authors.forename: R A
authors.initials: RA
authors.lastname: Christensen
authors.forename: A
authors.initials: A
authors.lastname: Konopka
authors.forename: C G
authors.initials: CG
authors.lastname: Scanes
authors.forename: H D
authors.initials: HD
authors.lastname: Hafs
mesh_terms: D000375:Aging / Q000502:physiology*; D000704:Analysis of Variance; D000818:Animals; D001823:Body Composition / Q000502:physiology*; D001835:Body Weight / Q000502:physiology*; D002455:Cell Division / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D004435:Eating / Q000502:physiology*; D005260:Female; D005434:Flow Cytometry / Q000379:methods / Q000662:veterinary; D006098:Granulocytes / Q000166:cytology / Q000187:drug effects / Q000502:physiology; D013006:Growth Hormone / Q000494:pharmacology*; D006736:Horses / Q000276:immunology* / Q000502:physiology*; D007121:Immunocompetence / Q000187:drug effects / Q000502:physiology*; D007958:Leukocyte Count / Q000187:drug effects; D008070:Lipopolysaccharides / Q000494:pharmacology; D018655:Lymphocyte Count / Q000187:drug effects; D008214:Lymphocytes / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D018482:Muscle, Skeletal / Q000187:drug effects / Q000502:physiology*; D010084:Oxidation-Reduction; D010835:Phytohemagglutinins / Q000494:pharmacology; D011043:Pokeweed Mitogens / Q000494:pharmacology; D013997:Time Factors
chemical_list: D008070:Lipopolysaccharides; D010835:Phytohemagglutinins; D011043:Pokeweed Mitogens; D013006:Growth Hormone