The effect of daily slaframine injection of salivary score, feed intake, ruminal pH, and circulating concentrations of somatotropin and insulin-like growth factor I.
In a randomized complete block design with repeated measures, ruminally cannulated crossbred beef steers (n = 24; 279 +/- 3.2 kg) had ad libitum access to a 90% concentrate diet and were injected daily with slaframine dichloride (SF) at doses of 0, 30, or 60 micrograms SF free-base/kg BW. On d 1, 2, 7, 14, and 21, salivary scores were determined hourly from -2 to 8 h relative to injection (0 h), and ruminal pH was measured at 0, 4, and 8 h. Feed intake was measured daily. Serum concentrations of somatotropin (ST) were measured in samples collected at 20-min intervals from -40 min to 8 h on d 2, 7, 14, and 21, and IGF-I was measured at 8 h. Mean salivary score increased with SF injection (P < .01; .4, 3.3, and 3.7 for 0, 30, and 60 micrograms of SF/kg BW, respectively), although there was a dose x day interaction (P < .01). Injection of SF reduced DMI (P < or = .01; 6.39, 4.95, and 2.64 kg of DM/d for 0, 30, and 60 micrograms of SF/kg BW, respectively). Mean ruminal pH was increased (P < .01); 6.03, 6.42, and 6.72 for 0, 30, and 60 micrograms of SF/kg BW, respectively). Steers administered 60 micrograms of SF/kg BW lost weight (P = .02; 15.1 and -20.3 kg for 0 and 60 micrograms of SF/kg BW, respectively).(ABSTRACT TRUNCATED AT 250 WORDS)
Hibbard
B
B
Upjohn Company, Kalamazoo, MI 49001, USA.
Moseley
W M
WM
Robinson
J A
JA
Boucher
J F
JF
D000470:Alkaloids / Q000008:administration & dosage / Q000494:pharmacology*; D000818:Animals; D001835:Body Weight / Q000187:drug effects; D002417:Cattle / Q000097:blood / Q000502:physiology*; D004435:Eating / Q000187:drug effects* / Q000502:physiology; D013006:Growth Hormone / Q000097:blood; D006863:Hydrogen-Ion Concentration; D007275:Injections, Intravenous; D007334:Insulin-Like Growth Factor I / Q000032:analysis; D016018:Least-Squares Analysis; D008297:Male; D010277:Parasympathomimetics / Q000008:administration & dosage / Q000494:pharmacology*; D011897:Random Allocation; D012417:Rumen / Q000187:drug effects / Q000502:physiology; D012469:Salivary Glands / Q000187:drug effects / Q000502:physiology; D012472:Salivation / Q000187:drug effects* / Q000502:physiology
D000470:Alkaloids; D010277:Parasympathomimetics; C009275:slaframine; D007334:Insulin-Like Growth Factor I; D013006:Growth Hormone