Effects of corn stalk inclusion rate on rumination and ruminal pH in finishing beef steers
2020
Jennings, J.S. | Lockard, C.L. | Tedeschi, L.O. | Lawrence, T.E.
The objective of this experiment was to measure feedlot performance, rumination, ruminal pH, and carcass characteristics of cattle consuming a finishing diet with increasing levels of corn stalks (CS).Fifty cross-bred steers (initial BW = 302 ± 27 kg) were randomly allocated to 1 of 3 dietary treatments: 5% (5CS; n = 17), 10% (10CS; n = 17), or 15% (15CS; n = 16) CS in a finishing diet based on steam-flaked corn. Experimental design was a randomized complete block, and data were analyzed using generalized random coefficients models. Rumination (min/d) was recorded from all the steers, and half of the steers (n = 27) received an indwelling rumen bolus to monitor pH.As CS inclusion rate increased, ADG and G:F decreased (P ≤ 0.05) linearly, whereas DMI of cattle consuming 10CS and 15CS was greater (P ≤ 0.05) than those consuming 5CS. Ruminal pH tended (P < 0.09) to be greatest in 15CS steers, whereas ruminal pH of 10CS and 5CS steers were not different. Rumination time was greatest (P ≤ 0.01) for steers consuming the 15CS diet and least with the 5CS diet (P = 0.03). Increasing dietary CS to 15% linearly decreased (P ≤ 0.04) fat thickness, YG, and marbling score and tended to decrease hot carcass weight (P = 0.10).Results of this study indicate that optimal dietary roughage inclusion of CS should be between 5 and 10% to optimize feedlot performance while maintaining rumination and ruminal pH.
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