Controlled ruminal infusion of sodium bicarbonate. 3. Influence of infusion dose on systemic acid-base status, minerals, and ruminal milieu

Autor: J.F. Hogue, M. Aslam, M.T. Van Koevering, P. Le Ruyet, W.B. Tucker, G.D. Adams, I.S. Shin, M. Lema, R.K. Vernon
Rok vydání: 1993
Předmět:
Zdroj: Journal of dairy science. 76(8)
ISSN: 0022-0302
Popis: Four ruminally cannulated, lactating Holstein cows were assigned to a 4 × 4 Latin square to monitor effects of intraruminal NaHCO 3 infusion on temporal changes in ruminal and systemic acid-base status and mineral metabolism. Twice daily from 2 to 4h postfeeding, cows were infused with 0, 110, 220, or 330g of NaHCO 3 dissolved in 3.8L of water. All cows had access to their TMR of sorghum silage and concentrate (35: 65, DM basis) for 2h twice daily. Ruminal fluid, blood, and urine were collected at feeding and every 30min postfeeding for 12h on the last day of each 14-d period. Total urine volume also was measured during this interval. Infusion of buffer increased ruminal fluid buffering capacity transiently at 4.5h postfeeding but otherwise did not markedly affect ruminal fluid acid-base status. Systemic acid-base status was unaffected by the buffer primarily because renal excretion of base successfully reduced systemic base load. Urine volume increased in response to NaHCO 3 infusion. Buffer infusion increased urinary excretion of Na, Mg, and K but decreased Ca excretion for 12h postfeeding; C1 excretion was not affected. Buffer infusion tended to increase total VFA in ruminal fluid. Our data indicate that homeostatic mechanisms can eliminate exogenous base via the kidneys; hence, acid-base status was not perturbed by infusion of NaHCO 3 . The increased excretion of Mg and K with buffer infusion indicates that the dietary requirements for these minerals may be increased by NaHCO 3 . Although loss of Ca through the urine was reduced by buffer infusion, this reduction may indicate reduced availability of Ca to the cow. The diuresis accompanying large doses of NaHCO 3 may increase dietary requirements for some minerals.
Databáze: OpenAIRE