Effects of Processing Method of Hybrid Rye for Cattle Backgrounding Diets.

Cereal rye is used to diversify crop rotations in the Northern Great Plains and can be harvested through grazing, processed as forage (hay or silage), or allowed to reach maturity for grain and straw. Although rye has not traditionally been used in growing and finishing cattle diets due to the occurrence of ergot. Recent hybrid germplasms have shown promise with increased yields and decreased ergot incidence. This study aimed to determine the effects of substituting dry-rolled or ground hybrid rye for dry rolled corn (DRC) on dry matter intake (DMI), growth performance and gain:feed (G:F) of growing beef steers. One-hundred-fifty crossbred steers [260 ± 22.3 kg, initial body weight (BW)] were transported to the Carrington Research Extension Center near Carrington, North Dakota, stratified by BW, and assigned to one of fifteen pens (n = 10 steers/pen) and three dietary treatments in a randomized block design. Hybrid rye was substituted on a dry matter basis for DRC as follows: a basal diet formulated 33.8% corn silage, 23.6% forage barley hay, 17.5% modified distillers grains and solubles (MDGS), and 3% supplement and limestone with either 22.1% DRC (CON), 22.1% dry rolled hybrid rye (RRYE), and 22.1% ground hybrid rye (GRYE) on a dry matter basis. Due to extreme cold windchill temperatures, steers were fed for a total of 64 days beginning October 24, 2022. Body weights were taken before feeding on Day 1, 2, 28, 63, and 64 with a 4% pencil shrink applied to the initial and final BW. Performance data including animal BW, average daily gain (ADG), DMI and G:F ratio were calculated. The monthly average of growth performance were analyzed using the repeated measures procedure of PROC MIXED in SAS 9.4 with pen serving as the experimental unit. Pre-planned contrasts (control vs rye; rolled rye vs ground rye, rolled rye vs control, and ground rye vs control) were analyzed. No differences in BW (P = 0.35), ADG (P = 0.19), DMI (P = 0.83), or G:F (P = 0.21) were detected due to the replacement of DRC with hybrid rye throughout the study (Table 1). Steers assigned to GRYE had increased G:F (P = 0.04) and tended (P = 0.05) to have greater ADG compared with RRYE throughout the study. Steers fed hybrid rye tended to have lesser BW (P = 0.06) than those fed DRC after the first 28-day weigh period. During the final 36 days, steer assigned to GRYE had increased ADG (P = 0.03) compared with RRYE and tended (P = 0.05) to have greater ADG than those assigned to CON. Results from the study suggest that steers fed processed hybrid rye grain in a high forage backgrounding diet performed similarly to calves fed DRC. [ABSTRACT FROM AUTHOR]