Evaluation of batch fraction, corn silage inclusion level, and mixing duration on long particle distribution of finishing diets for beef cattle.

Background:  Differing fractions of a batch of feed, differing ingredient characteristics, and inadequate mix time can lead to non-uniformity within a mix of feed.  Methods: The experiment was designed as a 5 x 2 x 2 factorial arrangement with seven replications per simple treatment mean. Factors included: 1) batch fraction (BF; n = 5); 2) corn silage inclusion level (CSLVL; n = 2) 15% or 30% inclusion (dry matter basis); and 3) mixing duration (DR; n = 2) of 20 or 25 mixer revolutions. Data were analyzed as a completely randomized design using a binomial approach. The Penn State Particle Separator was used to separate fractions of the total mixed ration (TMR). Results: No interactions between BF, CSLVL, and DR were detected ( P ≥ 0.31) for any dependent variables. There was an increase ( P = 0.01) in retention on the 19 mm sieve from the first BF compared to the last BF. CSLVL altered ( P = 0.01) retention on the 19 mm sieve. Increasing DR from 20 to 25 revolutions had no appreciable influence ( P = 0.23) on particles greater than 19 mm.  CSLVL ( P = 0.01) and DR ( P = 0.01) altered particle retention on the 8 mm sieve. BF ( P = 0.01), CSLVL ( P = 0.01), and DR ( P = 0.02), influenced particle retention on the 4 mm sieve. CSLVL impacted ( P ≤ 0.01) particles remaining in the bottom pan and particles greater than 4 mm. BF ( P = 0.01) and CSLVL ( P = 0.01) altered particles greater than 8 mm. Conclusions: These data indicate that BF and CSLVL fed alters particle size distribution that in turn could alter dry matter intake, dietary net energy content, and influence daily gain. Mixing DR had no appreciable influence on particle size distribution of the TMR.