For cattle to maximize feed efficiency, full utilization of starch digestion must occur. Our objectives were to evaluate feeding cattle corn containing an a amylase enzyme (Syngenta Enhanced Feed ...Corn: SYT-EFC) on site and extent of digestion and luminal pH parameters. Four ruminally and duodenally cannulated steers (BW = 264 ±13 kg) were utilized in a 6x4 Latin rectangle design with a 2 x 2 - 1 factorial arrangement of treatments. Factors included corn trait (SYT-EFC or CON), corn by-product type Sweet Bran (SB) or modified distillers grains plus solubles (MDGS), and a 50:50 blend of SYT-EFC and CON with MDGS. Period length was 21 d which consisted of 16 d adaptation and 5 d fecal and duodenal collection. Rumen microbial samples were collected via whole rumen contents on d 21 and were analyzed for purines. Titanium dioxide was dosed intraruminally on d 10-20 as a marker to determine digestibility and fecal output. Ruminal pH was measured continuously from d 17 to 21 with submersible. wireless pH probes. No interactions (P > 0.18) or main effect of com trait (P > 0.43) were observed for true ruminal starch or OM digestibilities. However, a tendency was observed for postruminal starch (P = 0.11) digestibility to be greater for steers fed SYT-EFC than CON. Postruminal OM digestibility was also increased in steers fed SYT-EFC compared to CON (P = 0.08). Tins resulted in steers fed SYT-EFC to have a decrease in fecal starch (P = 0.01) and OM (P = 0.05) output compared to CON. Ultimately, steers fed SYT-EFC had increased total tract starch, OM, and DM digestibilities (P = 0.01. P = 0.07. and P = 0.08. respectively) compared to CON. There were no interactions (P > 0.19) or main effect of corn trait (P > 0.30) for ruminal pH characteristics. These data would suggest that steers fed SYT-EFC were able to utilize starch in the small intestine to a greater extent than cattle fed CON leading to an overall greater total tract starch digestibility and ultimately improved feed efficiencies.
An abstract of a study by Jolly-Breithaupt et al determining the effect of adding corn oil to the diet on total tract digestibility of finishing cattle is presented. Fat intake was greatest and ...similar for MDGS+Oil and FFMDGS (P = 0.47) and intermediate for DOMDGS (P = 0.08), whereas fat intake was least for corn control diet (CON) (P < 0.01). Total tract OM digestibility was greatest for cattle fed CON (83.6%; P < 0.01), whereas DOMDGS and FFMDGS were intermediate and similar (79.1 and 78.1% for DOMDGS and FFMDGS, respectively; P > 0.39), and MDGS+Oil was lowest (75.6%) but similar to FFMDGS (P = 0.10). Total tract digestibility of NDF was greater for FFMDGS compared with CON and MDGS+Oil (P < 0.04) but not compared with DOMDGS. Feeding FFMDGS resulted in the greatest DE (Mcal/kg; P < 0.04), and DOMDGS was similar to both FFMDGS (P = 0.40) and CON (P = 0.17). However, feeding CON resulted in a lower DE compared with FFMDGS (P = 0.04). The MDGS+Oil diet had the lowest DE (P < 0.01). When corn oil was added back to MDGS, there was a negative impact on digestibility of OM and NDF as well as lower DE (Mcal/kg) compared with DOMDGS or FFMDGS.
A feedlot (Exp. 1) experiment was conducted to evaluate the effects of an essential oil mixture (EOM), experimental essential oil mixture (EXP), tylosin, and monensin (MON) on performance, carcass ...characteristics, and liver abscesses. A metabolism experiment (Exp. 2) was conducted to evaluate the effects of EOM. EXP. and MON on ruminal fermentation arid digestibility in finishing steers. In Exp. 1, 468 yearling steers (398 ± 34 kg initial BW) were used in 50 pens (10 pens/treatment) and received their respective dietary treatments for 115 d. Five dietary treatments were compared in Exp. 1: 1) control, no additives (CON): 2) EOM. 1.0 g/steer daily: 3) EX.P. 1.0 g/steer daily; .1) EOM. 1.0 g/steer daily plus tylosin, 90 mg/ steer daily (EOM+T): and 5) monensin, 300 mg/steel' daily plus tylosin, 90 mg/steer daily (MON+T). Compared with CON, steers fed MON+T had decreased DM1 (P < 0.01), and steers fed EOM+T and MON+T had improved G:F (P < 0.02). Average daily gain was not different among treatiiieiits (P > 0.5S). There was a trend (P = 0.09) for a treatment effect on 12th-rib fat thickness, which resulted in a significant increase in calculated yield grade for the EOM+T treatment. No at lieu carcass characteristics were affected by treatment (P »= 0.10). Prevalence of total liver abscesses was reduced for steers fed tvlosin compared with no tylosin (P < 0.05). In Exp. 2, 8 ruminally fistulated steers (399 + 49 kg initial BW) were assigned randomly to 1 of 1 treatments in a replicated 4 x 4 Latin square designed experiment. Treatments were 1) CON, 2) EOM. 3) EXP. and 4) MON with feeding rates similar to Exp. 1. There were no differences in DM1, OM intake, and aI)pal'ent total tract DI'vl or OM digestibilities among treatments (P > 0.30). Feed intake patterns were similar among feed additive treatments (P > 0.13). Total VFA (P = 0.10) and acetate (P = 0.06) concentrations tended to be affected by treatment with EOM numerically greater than CON. Average ruminal pH ranged from 5.59 to 5.72 and did not differ among treatments. Addition of a EOM or monensin to a diet containing tylosin improves G:F. 1 nit little difference was observed in metabolism or digestibility. PUBLICATION ABSTRACT
Abstract
The objective of this study was to determine the effects of two implant strategies compared to non-implanted heifers fed varying days on feed. Calf-fed heifers (n=720; initial BW=278, SD=25 ...kg) were utilized in a 3 x 4 factorial design and assigned randomly to pens, and pens assigned randomly to one of twelve treatments consisting of three implant treatments and four serial harvest groups. Implant strategies included a non-implanted control (CON), a re-implant strategy using an initial implant of Revalor-200 (Merck Animal Health, Madison, NJ) followed by Revalor-200 on day 100 (REV-200), or Revalor-XH on day 0 (REV-XH). Each implant provided 200 mg trenbolone acetate and 20 mg estradiol. Serial harvest groups consisted of heifers fed 151, 165, 179, or 193 days on feed (DOF). There were no (P ≥ 0.26) implant x serial harvest interactions for carcass-adjusted performance and carcass characteristics. Dry matter intake was not different among implant treatments or serial harvest groups (P ≥ 0.11 and P = 0.72, respectively). Carcass adjusted-final BW increased linearly (P < 0.01), while carcass-adjusted ADG and G:F tended to decrease linearly (P = 0.10) as DOF increased. There was no difference in dressing percentage (P = 0.49) as DOF increased and LM area tended to increase linearly as DOF increased (P = 0.09). Fat depth, marbling score and calculated yield grade increased linearly (P < 0.01) as DOF increased. Heifers implanted with REV-200 or REV-XH had greater (P ≤ 0.05) carcass-adjusted final BW and ADG compared to CON (P < 0.01), but were not different between REV-200 and REV-XH (P ≥ 0.55). Implanted heifers were more efficient than CON heifers (P = 0.05), and REV-XH tended (P = 0.07) to be more efficient than REV-200. Implanted heifers had 12 kg greater HCW compared to CON heifers (P < 0.01). No differences were observed in fat thickness (P = 0.25) or calculated yield grade (P = 0.71) among implant treatments. Marbling score was greater (P < 0.01) for CON compared to REV-200 and REV-XH and REV-XH tended to have a greater marbling score (P = 0.10) than REV-200. No differences were observed between a new implant (Revalor-XH) and an implant strategy using Revalor-200 on day 1 and day 100. Implanting and increasing DOF substantially increase HCW and revenue but yield grade discounts increase with greater fatness due to days fed.
The objective of this study was to determine the effects of two implant strategies compared to non-implanted heifers fed varying days on feed. Calf-fed heifers (n=720; initial BW=278, SD=25 kg) were ...utilized in a 3 x 4 factorial design and assigned randomly to pens, and pens assigned randomly to one of twelve treatments consisting of three implant treatments and four serial harvest groups. Implant strategies included a non-implanted control (CON), a re-implant strategy using an initial implant of Revalor-200 (Merck Animal Health, Madison, NJ) followed by Revalor-200 on day 100 (REV-200), or Revalor-XH on day 0 (REV-XH). Each implant provided 200 mg trenbolone acetate and 20 mg estradiol. Serial harvest groups consisted of heifers fed 151, 165, 179, or 193 days on feed (DOF). There were no (P ≥ 0.26) implant x serial harvest interactions for carcass-adjusted performance and carcass characteristics. Dry matter intake was not different among implant treatments or serial harvest groups (P ≥ 0.11 and P = 0.72, respectively). Carcass adjusted-final BW increased linearly (P < 0.01), while carcass-adjusted ADG and G:F tended to decrease linearly (P = 0.10) as DOF increased. There was no difference in dressing percentage (P = 0.49) as DOF increased and LM area tended to increase linearly as DOF increased (P = 0.09). Fat depth, marbling score and calculated yield grade increased linearly (P < 0.01) as DOF increased. Heifers implanted with REV-200 or REV-XH had greater (P ≤ 0.05) carcass-adjusted final BW and ADG compared to CON (P < 0.01), but were not different between REV-200 and REV-XH (P ≥ 0.55). Implanted heifers were more efficient than CON heifers (P = 0.05), and REV-XH tended (P = 0.07) to be more efficient than REV-200. Implanted heifers had 12 kg greater HCW compared to CON heifers (P < 0.01). No differences were observed in fat thickness (P = 0.25) or calculated yield grade (P = 0.71) among implant treatments. Marbling score was greater (P < 0.01) for CON compared to REV-200 and REV-XH and REV-XH tended to have a greater marbling score (P = 0.10) than REV-200. No differences were observed between a new implant (Revalor-XH) and an implant strategy using Revalor-200 on day 1 and day 100. Implanting and increasing DOF substantially increase HCW and revenue but yield grade discounts increase with greater fatness due to days fed.
An abstract of a study by Conroy et al evaluating the effects of fat, fiber, and protein found in distillers grains on performance of growing crossbred steers is presented. No other component ...appeared to contribute toward the greater energy value of MDGS relative to corn. Data from this study suggest that excess metabolizable protein as RUP contributes significantly to the feeding value of MDGS in growing diets.
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