J. O. Sarturi

Effects of silage type and inclusion level on ruminal characteristics and feeding behavior of steers fed finishing diets

Crossbred beef steers fitted with a ruminal cannula were used to study the effects of silage type (BH 8895 corn or AF7401 sorghum) and level of inclusion (10 or 20%) in beef cattle finishing diets on digestibility of nutrients, ruminal kinetics, in vitro methane production, and feeding behavior. A 4 × 6 unbalanced Latin square design was used (6 steers; 363 ± 23 kg; 4 diets: corn silage [CS] or sorghum silage [SS], both at 10 or 20% inclusion, DM basis). Each period consisted of 14 d of adaptation and 7 d of collection. Steers were fed once daily at 1000 h. An additional study evaluated the ruminal degradability of intact ensiled sorghum grain ruminally incubated in 3 steers (547 ± 56 kg BW), using the same hybrids from the main study from 10 laboratory experimental silos. The GLIMMIX procedures of SAS were used for statistical analyses. Steers fed SS had greater NDF intake ( < 0.01) compared with the ones fed CS. The magnitude of the NDF intake change depended on the level of inclusion ( < 0.01), which was 6 and 16% for 10 and 20% inclusion, respectively. Regardless the level of inclusion, CS diets promoted greater ( ≤ 0.01) apparent total tract digestibility of nutrients evaluated (DM, OM, NDF, ADF, hemicellulose, and starch) compared with SS diets. Steers fed SS diets tended to chew 1.1 h/d more ( = 0.07) than steers fed CS diets. The level of inclusion increased ( = 0.02) the chewing time per day by 1.3 h. No major differences were observed in any of the ruminal pH and in vitro gas production variables evaluated for silage type and inclusion level ( ≥ 0.09). The CS-fed steers had 12% greater total VFA concentration and an 18.5% lower ( < 0.01) acetate-to-propionate ratio compared with SS-fed steers. The acetate-to-propionate ratio was 16% greater ( < 0.01) when steers were fed SS compared with when steers were fed CS. The CS samples were more extensively ruminally degraded ( < 0.01) than the SS samples. Greater ( < 0.01) NDF ruminal disappearance was observed in ruminal environments containing 20% silage compared with those containing 10% silage. After 96 h inside the rumen, intact ensiled sorghum grain degradability of DM reached only 51.7%. Replacing CS with SS in beef finishing diets (low roughage inclusion) requires adjustments to balance dietary energy. Sorghum material induced a desirable roughage effect in feeding behavior but also offered the potential for improved regarding fiber digestibility and intact grain ruminal degradability.

Effects of a live yeast in natural-program finishing feedlot diets on growth performance, digestibility, carcass characteristics, and feeding behavior

Effects of live yeast (Saccharomyces cerevisiae) in steam-flaked corn-based diets fed to natural-program beef cattle on growth performance, total tract apparent digestibility, carcass characteristics, and feeding behavior were evaluated in a randomized block design experiment. Steers (n = 144; 341 ± 7.03 kg) were blocked by initial BW and assigned randomly to 1 of the 3 treatments (n = 12 pens per treatment with 4 steers per pen). Treatments included the following: 1) control (CTL; no yeast); 2) low yeast (LY; 1.5 g/animal daily [3 × 1010 CFU]); and 3) high yeast (HY; 3.0 g/animal daily [6 × 1010 CFU]). Technologies such as implants, ionophores, and antibiotics were not used, and the steam-flaked corn-based finishing diets were fed to provide ad libitum access to feed. Yeast was included in a cottonseed meal-based premix as 1% of the dietary DM. Spot fecal samples (twice daily for 5 consecutive days) and diets were composited by pen and analyzed for acid insoluble ash to estimate apparent total tract digestibility of nutrients. Cattle were slaughtered on days 183 (4 blocks) and 204 (8 blocks). Dry matter intake (P ≥ 0.29), ADG (P ≥ 0.17), and G:F (P ≥ 0.33) did not differ among treatments. The percentage of Premium Choice (P < 0.01) carcasses increased linearly with increasing yeast inclusion in the diet. A quadratic response was observed for total tract apparent digestibility, in which steers fed LY had greater digestibility (P < 0.01) of DM by 5.4%, OM by 4.8%, NDF by 15.2%, ADF by 20.2%, CP by 6.2%, and ether extract (EE) by 2.5% compared with steers fed CTL. Feeding behavior was not affected (P = 0.28) by treatments. Live yeast improved digestibility of DM, OM, CP, EE, and fiber, without changing feeding behavior and growth performance of natural-program steers fed steam-flaked corn-based finishing diets.

Effects of tannic acid on growth performance, carcass characteristics, digestibility, nitrogen volatilization, and meat lipid oxidation of steers fed steam-flaked corn–based finishing diets

Effects of a tannic acid blend (ByPro; Silvateam USA, Ontario, CA) added to steam-flaked corn-based fishing diets on beef cattle growth performance, carcass characteristics, nutrient digestibility, fecal N volatilization, and meat lipid oxidation were evaluated. Steers ( = 144; 349 ± 25 kg initial BW) were blocked by initial BW and assigned randomly to 1 of 3 treatments with 12 pens/treatment and 4 steers/pen and fed ad libitum. Treatments included a control (CON; no ByPro) and ByPro fed at 30 or 60 g DM/steer daily (30-ByPro and 60-ByPro, respectively). Pen fecal samples were collected 7 d after cattle were shipped to slaughter for estimation of N volatilization. Strip loins were aged for 21 d for evaluation of color and antioxidant activity. Intake quadratically increased ( = 0.05) from d 0 to 35, whereas linear trends were observed for increased DMI from d 0 to 105 and d 0 to slaughter ( = 0.07 and = 0.06, respectively), resulting in a 3.7% greater overall DMI for 60-ByPro than for CON. No differences were detected for carcass-adjusted ADG ( = 0.65) or G:F ( = 0.17). Carcass characteristics including HCW ( = 0.52), fat thickness ( = 0.32), LM area ( = 0.57), quality grade ( = 0.44), yield grade ( = 0.29), and percentage of condemned livers ( = 0.13) were not affected by treatments. Apparent total tract digestibility of starch linearly decreased tendency ( = 0.03) with increasing ByPro dose, whereas tends for a linear decrease ( = 0.09) in CP and a quadratic increase ( = 0.09) in OM digestibility were observed. No effects of treatment ( ≥ 0.39) were noted for fecal N volatilization. An increase ( < 0.01) in metmyoglobin in strip loin steaks was observed with ByPro inclusion. Oxymyoglobin decreased ( < 0.01) as display day progressed, except on d 5, at which time CON and 30-ByPro steaks had lower proportions than 60-ByPro steaks. Only subtle changes in discoloration ratio and deoxymyoglobin were observed, whereas no effects ( ≥ 0.43) for pH or thiobarbituric acid reactive substances were noted. Feeding ByPro increased DMI during the first half of the feeding period without negatively affecting gain efficiency; however, fecal N retention was not altered by ByPro. ByPro did not negatively affect meat quality or carcass characteristics, and it did not seem to affect retail meat antioxidant activity.

Biofuel feedstock and blended coproducts compared with deoiled corn distillers grains in feedlot diets: Effects on cattle growth performance, apparent total tract nutrient digestibility, and carcass characteristics

Crossbred steers (British × Continental; = 192; initial BW 391 ± 28 kg) were used to evaluate the effects of feeding ethanol coproducts on feedlot cattle growth performance, apparent nutrient digestibility, and carcass characteristics. Steers were blocked by initial BW and assigned randomly to 1 of 6 dietary treatments within block. Treatments (replicated in 8 pens with 4 steers/pen) included 1) control, steam-flaked corn-based diet (CTL), 2) corn dried distillers grains with solubles (DGS; DRY-C), 3) deoiled corn dried DGS (DRY-CLF), 4) blended 50/50 corn/sorghum dried DGS (DRY-C/S), 5) sorghum dried DGS (DRY-S), and 6) sorghum wet DGS (WET-S). Inclusion of DGS was 25% (DM basis). The DGS diets were isonitrogenous, CTL was formulated for 13.5% CP, and all diets were balanced for ether extract. Final shrunk BW, ADG, and DMI did not differ among CTL and DGS treatments ( ≥ 0.19). Overall G:F did not differ from CTL for DRY-C, DRY-CLF, or WET-S ( ≥ 0.12); however, G:F was 9.6% less for DRY-S compared with CTL ( < 0.01) and tended ( = 0.09) to be less for DRY-C/S than CTL. For grain source, ADG and G:F were less for DRY-S vs. DRY-C ( < 0.05), but blending DRY-C/S tended ( = 0.07) to increase ADG and increased ( = 0.05) carcass-adjusted G:F vs. DRY-S. For WET-S, final BW and ADG were greater ( < 0.05), and G:F tended ( = 0.06) to be greater than for DRY-S. There was no difference in ADG, DMI, or G:F of steers fed DRY-C vs. DRY-CLF ( ≥ 0.35). Apparent DM and OM digestibility did not differ for CTL, DRY-C, DRY-CLF, and WET-S ( ≥ 0.30) but were lower for DRY-C/S and DRY-S ( < 0.05). Nutrient digestibility was lower for DRY-S vs. DRY-C ( < 0.01), but apparent digestibility of OM, DM, NDF, ADF, CP, ether extract, and starch were increased ( < 0.01) for DRY-C/S vs. DRY-S. Although starch digestibility did not differ between DRY-S and WET-S ( 0.18), digestibility of other measured nutrients was greater for WET-S vs. DRY-S ( < 0.01). Ether extract digestibility was greater for DRY-CLF vs. DRY-C ( < 0.05). Carcass weight, dressing percent, and marbling score did not differ between CTL and DGS diets ( ≥ 0.23). For DRY-S, HCW was lower than for DRY-C ( = 0.02); however, compared with DRY-S, HCW tended to be greater for DRY-C/S ( = 0.10) and WET-S ( = 0.07). At a moderately high (25% DM) inclusion, blending C/S or feeding WET-S resulted in cattle growth performance and carcass characteristics similar to those of CTL and corn-based coproducts.