Timing of Intake a Multi-Science in Ruminant Ecology:Rumen Dynamics

The objective was to establish effects of providing a total mixed ration (TMR) at either 0900 or 2100 h on rumen volume, passage kinetics, and microbial protein biomass in lactating cows. Four multiparous and four primiparous Holstein cows were used in a cross over design study with two 6-week periods, each with 3-week adaptation. Total urine was collected during a sampling week in each period to measure urinary excretion of purine derivatives to estimate microbial protein biomass. Rumen ammonia concentrations were lower in primiparous cows fed at 2100 vs. 0900 h (10 vs. 11 mg/L, P<0.05). Rumen propionate was lower (26.5 vs. 28 mmol/L) and the acetate to propionate ratio was higher (2.1 vs. 1.9) in multiparous cows fed at 2100 vs. 0900 h. Microbial protein estimates were not significantly affected by eating time. Evening fed cows tended to experience a greater rumen volume than morning fed cows (107 vs. 90 L, P<0.010). Therefore, feed delivery at 2100 vs. 0900 h increased rumen volume and fermentation without significantly affecting microbial protein synthesis.

کلیدواژه ها:

Feeding time ، Evening eating ، Rumen ، Physiology ، Holstein cow