Effect of feed delivery fluctuations and feeding time on ruminal acidosis, growth performance, and feeding behavior of feedlot cattle.

Research was conducted to determine whether fluctuations in the amount of feed delivered and timing of feeding affect ruminal pH and growth of feedlot cattle. In Exp. 1, the effects of constant (C) vs. fluctuating (F) daily feed delivery on ruminal pH were assessed in a crossover experiment (two 28-d periods) involving six mature, ruminally cannulated steers. The diet consisted of 86.8% barley grain, 4.9% supplement, and 8.3% barley silage (DM basis) and was offered ad libitum for 2 wk to estimate DMI by individual steers. Steers in group C were offered a constant amount of feed daily equal to their predetermined DMI, whereas steers in group F were offered 10% more or less than their predetermined DMI on a rotating 3-d schedule. Ruminal pH of each steer was measured continuously via an indwelling electrode placed in the rumen during the last 6 d of each period. Mean pH tended to be lower (0.10 units) for F than C (5.63 vs. 5.73; P = 0.15), and ruminal pH of steers in group F tended to remain below 5.8 (P = 0.03) or 5.5 (P = 0.14) for greater proportions of the day than steers in group C. Inconsistent delivery of feed lowered ruminal pH, suggesting increased risk of subclinical acidosis. In Exp. 2, a 2 x 2 factorial was used to study the effects of pattern (C vs. F) and feeding time (morning [0900] vs. evening [2100]) on the feeding behavior and performance of 234 (310 +/- 23 kg) Charolais x Hereford beef steers during backgrounding and finishing phases over 209 d. One pen per treatment was equipped with a radio frequency identification (GrowSafe Systems Ltd., Airdrie, Canada) system that monitored bunk attendance by each steer throughout the trial. Pattern of feed delivery did not affect (P = 0.16) DMI (7.36 kg/d), ADG (1.23 kg/d), G:F (0.17), or time spent at the bunk (141 min/d), nor were pattern of feed delivery x time of feeding interactions observed (P = 0.18). Late feeding increased (P < 0.05) daily DMI (7.48 vs. 7.26 kg), ADG (1.28 vs. 1.00 kg/d), and G:F (0.21 vs. 0.15). These studies indicate that the risk of subclinical acidosis was increased with fluctuating delivery of feed, but the greater risk of acidosis did not impair growth performance by feedlot cattle. Consequently, daily intake fluctuations of 10% DMI or less that do not alter overall intake by feedlot cattle are unlikely to have any negative consequences on growth performance.

[1]  K. Beauchemin,et al.  Effect of grain processing and silage on microbial protein synthesis and nutrient digestibility in beef cattle fed barley-based diets. , 2003, Journal of animal science.

[2]  K. Schwartzkopf-Genswein,et al.  Effect of bunk management on feeding behavior, ruminal acidosis and performance of feedlot cattle: A review , 2003 .

[3]  K. Beauchemin,et al.  Effects of pH and fibrolytic enzymes on digestibility, bacterial protein synthesis, and fermentation in continuous culture , 2002 .

[4]  G. Ghorbani,et al.  Effects of bacterial direct-fed microbials on ruminal fermentation, blood variables, and the microbial populations of feedlot cattle. , 2002, Journal of animal science.

[5]  Tim A. McAllister,et al.  Relationships between bunk attendance, intake and performance of steers and heifers on varying feeding regimes , 2002 .

[6]  K. Beauchemin,et al.  Effects of barley grain processing on the site and extent of digestion of beef feedlot finishing diets. , 2001, Journal of animal science.

[7]  P. Weimer,et al.  Initial Ph as a Determinant of Cellulose Digestion Rate by Mixed Ruminal Microorganisms in Vitro , 2022 .

[8]  C. Krehbiel,et al.  Influence of Feed Intake Fluctuation, Feeding Frequency, Time of Feeding, and Rate of Gain on Performance by Limit-Fed Steers1 , 2000 .

[9]  Tim A. McAllister,et al.  Validation of a radio frequency identification system for monitoring the feeding patterns of feedlot cattle , 1999 .

[10]  T. Klopfenstein,et al.  Effects of imposed feed intake variation on acidosis and performance of finishing steers. , 1999, Journal of animal science.

[11]  T. Mcallister,et al.  Bunk attendance of feedlot cattle monitored with radio frequency technology , 1998 .

[12]  B. Sowell,et al.  Radio frequency technology to measure feeding behavior and health of feedlot steers , 1998 .

[13]  D. Wilson,et al.  Why are ruminal cellulolytic bacteria unable to digest cellulose at low pH? , 1996, Journal of dairy science.

[14]  C. Krehbiel,et al.  Effect of level and type of fat on subacute acidosis in cattle fed dry-rolled corn finishing diets. , 1995, Journal of animal science.

[15]  J. Merks,et al.  Patterns of daily food intake in growing pigs , 1992 .

[16]  T. Klopfenstein,et al.  Adaptation to High Concentrate Diets by Beef Cattle. I. Adaptation to Corn and Wheat Diets , 1979 .

[17]  M. Galyean,et al.  Application of research findings and summary of research needs: Bud Britton Memorial Symposium on Metabolic Disorders of Feedlot Cattle. , 1998, Journal of Animal Science.

[18]  F. Owens,et al.  Acidosis in cattle: a review. , 1998, Journal of animal science.

[19]  W. Stroup,et al.  Effect of monensin and monensin and tylosin combination on feed intake variation of feedlot steers. , 1995, Journal of animal science.

[20]  R. T. Brandt,et al.  Effect of morning vs evening feeding of limit-fed Holsteins during summer months , 1994 .

[21]  R. Stock,et al.  Acidosis, rate of starch digestion and intake , 1987 .