Hematological profiles in dairy cows treated with recombinant bovine somatotropin.
Recombinant bovine somatotropin (bST) was administered at 0, 10.3, or 20.6 mg per cow per day to 32 Holsteins for 38 wk. Fifteen currently treated cows had been treated in the previous lactation. Eighteen hematological variables and blood concentration of insulin-like growth factor I (IGF-I) were measured at five sample periods. The objectives of the study were to test the effects of bST treatments on hematological profiles and to relate blood IGF-I concentration to these variables. Results indicated little influence (P greater than .10) of previous bST treatments on hematological profiles measured in the current lactation. Current bST treatments, however, altered hematocrits (P = .10), mean corpuscular volume (P = .03), mean corpuscular hemoglobin (P = .009), and fraction of blood lymphocytes (P = .09). A week x bST treatment interaction also contributed to variation in hematocrit (P = .09), mean corpuscular hemoglobin (P = .05), fraction of neutrophils (P = .02), and fraction of lymphocytes (P = .04). Blood IGF-I concentration influenced fractions and counts of neutrophils (P = .06, .09), lymphocytes (P = .04, .02), and monocytes (P = .08, .05). Further in vivo and in vitro studies are warranted because this preliminary evidence suggests that bST and(or) IGF-I contribute to regulation of hematopoiesis in mature dairy cows.
Burton
J L
JL
Department of Animal and Poultry Science, University of Guelph, Ontario, Canada.
McBride
B W
BW
Kennedy
B W
BW
Burton
J H
JH
Elsasser
T H
TH
Woodward
B
B
D000704:Analysis of Variance; D000818:Animals; D001773:Blood Cells / Q000187:drug effects*; D002417:Cattle / Q000097:blood*; D004906:Erythrocyte Count / Q000662:veterinary; D005260:Female; D013006:Growth Hormone / Q000494:pharmacology*; D006400:Hematocrit / Q000662:veterinary; D007334:Insulin-Like Growth Factor I / Q000032:analysis*; D007958:Leukocyte Count / Q000662:veterinary; D011994:Recombinant Proteins / Q000494:pharmacology
D011994:Recombinant Proteins; D007334:Insulin-Like Growth Factor I; D013006:Growth Hormone