Researchers in Italy recently conducted a study to determine the effects of processing time of a total mixed ration (TMR) on its physical and chemical characteristics, consistency over time, as well as performance of beef cattle in a finishing environment.

Giorgio Marchesini, Martina Cortese, Nicola Ughelini, Rebecca Ricci, Maria Chinello, Barbara Contiero and Igino Andrighetto with the Università degli Studi di Padova in Legnaro, Italy, conducted their trial with 98 Charolais bulls, with an initial bodyweight of about 476 kg, that were randomly assigned to two groups: group 1 had 54 animals in six pens, and group 2 had 44 animals in five pens.

Marchesini et al. noted that the two groups were fed rations of the same composition but that were mixed for either a short (20 minutes) mixing time or for a longer mixing time (30 minutes).

The trial lasted 60 days and was divided into two periods. After the first period, the diets were exchanged between groups according to a crossover design.

Animals were assessed for average daily weight gain (ADG), dry matter intake, feed conversion ratio (FCR), rumination and activity.

According to Marchesini et al., the longer-mixed ration had a lower particle geometric mean length than the short-mixed ration (4.12 mm versus 5.08 mm; P < 0.001).

Bulls fed the diet mixed for 30 minutes showed a significantly higher ADG (1.96 kg versus 1.87 kg per day; P  = 0.035) and a lower FCR (4.97 versus 5.39; P = 0.036) compared with animals fed the diet mixed for 20 minutes, the researchers reported.

Average daily rumination time and activity level did not differ between mixing times and were 381 minutes and 494 binary digits, respectively, but bulls fed diet mixed for 30 minutes showed a lower (0.083 versus 0.095; P = 0.012) index of dishomogeneity in activity and a lower sorting activity against long particles (99.8% versus 96.3%; P = 0.005), Marchesini et al. said.

The researchers added that the variation of TMR composition between one day and another was significant (P < 0.001) for both neutral detergent fiber and starch in the ration mixed 20 minutes, whereas in the longer-mixed ration, it showed a tendency to significance (P  = 0.056) only for neutral detergent fiber.

Marchesini et al. concluded that mixing finishing rations for a longer period improved TMR consistency, ADG and FCR as well as reduced feed sorting.

The research was published in Animal Feed Science & Technology.