315 Feeding Behavior of Beef Steers Consuming Finishing Diets with Added Nutritional Packet

2021 ◽  
Vol 99 (Supplement_3) ◽  
pp. 170-170
Author(s):  
Igor Gomes Fávero ◽  
Jhones O Onorino Sarturi ◽  
Kaue T Tonelli Nardi ◽  
Daren D Henry ◽  
Kaliu G Scaranto Silva ◽  
...  
Keyword(s):  
Feeding Behavior ◽  
Block Design ◽  
Vitamin B1 ◽  
Experimental Unit ◽  
Beef Steers ◽  
Yeast Saccharomyces Cerevisiae ◽  
Eating Time ◽  
Finishing Diets ◽  
D 63 ◽  
Randomized Complete Block Design

Abstract The effects of a nutritional packet fed to beef steers during the feedlot finishing phase (final 64 d) on feeding behavior were evaluated. Crossbred-Angus steers (n = 120; initial BW = 544 ± 52 kg) were assigned to 30 pens (4 steers/pen; 15 pens/treatment; pen = experimental unit) in a randomized complete block design. Steers were fed, ad libitum, a steam-flaked corn-based finishing diet and treatments were applied as follows: 1) control and 2) 30 g/steer-daily (DM-basis) of a nutritional packet (containing live yeast [Saccharomyces cerevisiae; 8.7 Log CFU/g], vitamin C [5.4 g/kg], vitamin B1 [13.33 g/kg], NaCl [80 g/kg], and KCl [80 g/kg]). The nutritional packet used ground corn as a carrier and was included at 1% of diet DM. Orts were subtracted from the total dietary DM offered to calculate DM intake. Feeding behavior activities were visually assessed by trained personnel twice (d 27 and d 63) for 24 h, when time spent on each activity was recorded every 5 min. Data were analyzed using the GLIMMIX procedure of SAS. Treatment × period interactions (P ≤ 0.03) were observed for eating time (min/d) and eating rates (min/kg of consumed DM, OM, fiber, and digestible DM, OM, and fiber), in which steers fed the nutritional packet spent less time in such activities on d 27 and more time during the assessment on d 63, compared with control. Regardless of period, steers fed the nutritional packet tended (P = 0.07) to spend less time chewing per kg of digestible ADF. Rumination (P ≥ 0.28), drinking (P ≥ 0.40), active (P ≥ 0.92), and resting (P ≥ 0.53) times were not affected by treatment. The nutritional packet affected eating behavior more intensively during the first 27 d of treatment, and digestible ADF seems to be the main feed-fraction inducing such effect.

309 Nutrient Digestibility of Beef Steers Consuming Finishing Diets with an Added Nutritional Packet

2021 ◽  
Vol 99 (Supplement_3) ◽  
pp. 168-169
Author(s):  
Kaue T Tonelli Nardi ◽  
Jhones O Onorino Sarturi ◽  
Darren D Henry ◽  
Francine M Ciriaco ◽  
Nelson O Huerta-Leidenz ◽  
...  
Keyword(s):  
Block Design ◽  
Vitamin B1 ◽  
Nutrient Digestibility ◽  
Experimental Unit ◽  
Beef Steers ◽  
Yeast Saccharomyces Cerevisiae ◽  
Finishing Diets ◽  
Time Of Feeding ◽  
Internal Marker ◽  
Feed Samples

Abstract The effects of a nutritional packet fed to beef steers during the final 64 d of the feedlot finishing phase on apparent total tract nutrient digestibility were evaluated. Angus-crossbred steers (n =120; initial BW = 544 ± 52 kg) were assigned to 30 pens (4 steers/pen; 15 pens/treatment; pen = experimental unit) in a randomized complete block design. A steam-flaked corn-based finishing diet was fed ad libitum and treatments applied as follows: 1) control and 2) 30 g/steer-daily (DM-basis) of the nutritional packet [containing live yeast (Saccharomyces cerevisiae; 8.7 Log CFU/g), vitamin C (5.4 g/kg), vitamin B1 (13.33 g/kg), NaCl (80 g/kg) and KCl (80 g/kg)]. The nutritional packet used ground corn as a carrier and was included at 1% of diet DM. Orts were quantified daily (if any) and subtracted from the total dietary DM offered to calculate DM intake. Fecal samples were collected twice daily (0700 and 1700 h) for 5 consecutive days (d 47 to 51) from at least 3 steers within pen. Feed samples were collected daily at time of feeding (0630 h). Fecal and feed samples were composited to represent the collection period, dried (55oC), ground (1 mm), and analyzed to assess DM, OM, NDF, ADF, and hemicellulose. In situ (288 h) iNDF was used as an internal marker to measure apparent total tract nutrient digestibility. Data were analyzed using the GLIMMIX procedure of SAS. Intake of DM, OM, and fiber components during the digestibility period was not affected (P ≥ 0.44) by treatment. Steers fed the nutritional packet had increased apparent total tract digestibility of OM (P = 0.02), DM (P = 0.01), NDF (P = 0.02), ADF (P = 0.01), and hemicellulose (P = 0.08; tendency). Improved nutrient digestibility without affecting nutrient intake may warrant an enhanced energy deposition in the carcass.

PSVI-30 Feedlot performance and carcass characteristics of beef steers under intensive management with or without an added nutritional packet

2021 ◽  
Vol 99 (Supplement_3) ◽  
pp. 446-446
Author(s):  
Andrea M Osorio ◽  
Kaue Tonelli Nardi ◽  
Igor Gomes Fávero ◽  
Kaliu G Scaranto Silva ◽  
Kymberly D Coello ◽  
...  
Keyword(s):  
Block Design ◽  
Random Effect ◽  
Vitamin B1 ◽  
Carcass Characteristics ◽  
Quality Data ◽  
Experimental Unit ◽  
Beef Steers ◽  
Intensive Management ◽  
Feedlot Performance ◽  
Yeast Saccharomyces Cerevisiae

Abstract The effects of a nutritional packet on performance and carcass characteristics of feedlot beef steers were evaluated. Thirty Angus-crossbred steers (BW = 542 ± 8.4 kg) were used in a randomized complete block design and allocated into pens with SmartFeed (C-Lock; 15 steers/treatment). Steers were consuming a steam-flaked corn-based finishing-diet, ad libitum, for the last 65-d on feed prior to slaughter, in which treatments were: 1) control and 2) a nutritional-packet [0.29% DM basis; live yeast (Saccharomyces cerevisiae; 8.7 Log CFU/g); Vitamin C (5.4 g/kg); Vitamin B1 (13.33 g/kg); NaCl (80 g/kg); KCl (80 g/kg)]. Individual BW was recorded every 14 d and carcass quality data was collected at slaughter. Steer was considered the experimental unit. The MIXED procedure of SAS was used with the fixed effect of treatment and the random effect of block. Total DMI was unaffected (P = 0.610) by treatment from d 0–65; however, control steers had greater (P = 0.030) DMI from d 54–65. The G:F was unaffected (P = 0.830) by treatment from d 0–35; however, it was greater (P ≤ 0.001) for steers fed the nutritional packet from d 0–50, and 0–65. Treatment did not affect (P = 0.920) ADG from d 0–35, however it increased (P ≤ 0.001) ADG from d 0–50 and tended (P = 0.060) to increase ADG from d 0–65. Carcass adjusted final BW tended (P = 0.060) to increase by 28% for treated cattle, whereas the Longissimus dorsi area tended to decrease (P = 0.090). No differences (P = 0.240) were observed for fat thickness, while yield-grade (P = 0.03) increased for treated cattle. The nutritional packet appears to improve performance in the final days of feeding steers under intensive management, and energy partitioning may be altered to fat deposition.

310 Growth Performance and Carcass Characteristics of Beef Steers Consuming Finishing Diets with an Added Nutritional Packet

2021 ◽  
Vol 99 (Supplement_3) ◽  
pp. 169-169
Author(s):  
Kaue T Tonelli Nardi ◽  
Jhones O Onorino Sarturi ◽  
Darren D Henry ◽  
Francine M Ciriaco ◽  
Nelson O Huerta-Leidenz ◽  
...  
Keyword(s):  
Growth Performance ◽  
Block Design ◽  
Average Daily Gain ◽  
Vitamin B1 ◽  
Carcass Characteristics ◽  
Fat Deposition ◽  
Experimental Unit ◽  
Thiamine Hydrochloride ◽  
Beef Steers ◽  
Finishing Diets

Abstract The effects of a nutritional packet fed to beef steers during the final 64 d of the feedlot finishing phase on growth performance and carcass characteristics were evaluated. Crossbred-Angus steers (n = 120; initial BW = 544 ± 52 kg) were assigned to 30 pens (4 steers/pen; 15 pens/treatment) in a randomized complete block design where pen represented the experimental unit. A steam-flaked corn-based finishing diet was fed ad libitum, and treatments were applied as follows: 1) control and 2) 30 g/steer-daily (DM-basis) of the nutritional packet (containing live yeast [8.7 Log CFU of Saccharomyces cerevisiae], vitamin C [5.4 g/kg of Ascorbic acid], vitamin B1 [13.33 g/kg of Thiamine hydrochloride], sodium chloride [80 g/kg] and potassium chloride [80 g/kg]). The nutritional packet used ground corn as a carrier and was included at 1 % of diet DM. Orts were quantified daily (if any) and subtracted from the total dietary DM offered to calculate DM intake. Unshrunk BW were collected on d 0, 21, 42 and 64 before daily feeding at 0630 h. Data were analyzed using the GLIMMIX procedure of SAS. Average daily gain (P = 0.89), dry matter intake (P = 0.57) and, gain:feed (P = 0.66) were not affected by the inclusion of the nutritional packet. The 12th rib fat deposition was increased (P ≤ 0.02) for cattle fed the nutritional packet compared with control (15.70 vs. 13.36 mm, respectively). Consequently, calculated yield grade was also increased (P ≤ 0.03) for cattle consuming the nutritional packet (3.32 vs. 3.02). An improved carcass fat-deposition without any deleterious effects on growth performance potentially warrant less days on feed when cattle receive such nutritional packet.

PSXV-23 Effects of a nutritional packet composed of live yeast, vitamins, and electrolytes on the feeding behavior of intensively managed beef steers

2021 ◽  
Vol 99 (Supplement_3) ◽  
pp. 323-324
Author(s):  
Kymberly D Coello ◽  
Andrea M Osorio ◽  
Kaue Tonelli Nardi ◽  
Kaliu G Scaranto Silva ◽  
Angel A Raudales ◽  
...  
Keyword(s):  
Feeding Behavior ◽  
Block Design ◽  
Random Effect ◽  
Neutral Detergent Fiber ◽  
Experimental Unit ◽  
Beef Steers ◽  
Eating Time ◽  
Ch4 Production ◽  
Intensively Managed ◽  
Live Yeast

Abstract The effect of a nutritional-packet was evaluated on time spent ruminating, eating, and chewing (ruminating + eating) by intensively managed beef steers consuming a finishing diet during the final 65 d of feeding prior to slaughter. Furthermore, the influence of behavior on CH4 production was determined. Twenty-four Angus-crossbreed steers were distributed into pens with SmartFeed (C-Lock) technology in which they were treated with: control or nutritional-packet [0.29% DM basis; live yeast (8.7 Log CFU/g); Vitamin C (5.4 g/kg); Vitamin B1 (13.33 g/kg); NaCl (80 g/kg); KCl (80 g/kg)]. An ear tag containing multiple accelerometers (CowManager) was placed on steers, and such device continuously recorded rumination and eating time (min/day). Enteric CH4 emissions were measured for 15 d using the SF6 tracer technique. Feeding behavior data were analyzed as a randomized complete block design using the MIXED procedure of SAS. The model included the fixed effect of treatment and the random effect of block. Steer was considered experimental unit. The GLM procedure of SAS was used for regressing behavior and CH4 production data. There were no differences between treatments for time (within 24 h) spent ruminating, eating, or chewing (P ³ 0.197). When nutrient intake was taken into account, no differences (P ³ 0.139) were observed between treatments for time spent ruminating, eating, and chewing per kg of dry matter, organic matter, neutral detergent fiber intake, and acid detergent fiber intakes. The production of CH4 was not affected by time spent ruminating (0.93 g/min; R2 = 0.0003; P = 0.935), eating (3.34 g/min; R2 = 0.03; P = 0.409), or chewing (0.69 g/min; R2 = 0.006; P = 0.728). The feeding behavior of intensively managed beef steers during the final 65-d of feeding was not driven by the nutritional-packet supplied, neither was CH4 production associated with feeding behavior variables measured.

scholarly journals Increasing hay inclusion in silage-based receiving diets and its effects on performance and energy utilization in newly weaned beef steers

2020 ◽  
Vol 4 (2) ◽  
pp. 848-853
Author(s):  
Dathan T Smerchek ◽  
Elizabeth M Buckhaus ◽  
Katie D Miller ◽  
Zachary K Smith
Keyword(s):  
Growth Performance ◽  
Block Design ◽  
Corn Silage ◽  
Energy Utilization ◽  
Experimental Unit ◽  
Net Energy ◽  
Beef Steers ◽  
Linear Effect ◽  
Randomized Complete Block Design ◽  
Red Angus

Abstract The influence of grass hay (GH) inclusion in replacement of corn silage in receiving diets on growth performance and dietary net energy (NE) utilization was evaluated in newly weaned beef steers (n = 162 Charolais-Red Angus cross steers; initial body weight [BW] = 278 ± 13.4 kg). Treatments were (DM basis): 1) 0% GH, 2) 10% GH, or 3) 20% GH inclusion in replacement of corn silage in receiving diets fed to newly weaned beef steers for 56 d. The study was conducted from October to December of 2019. Data were analyzed as randomized complete block design with pen serving as the experimental unit for all analyses. Increasing dietary inclusion of hay had no influence (P ≥ 0.11) on final BW, ADG, gain:feed or observed/expected dietary NEM and NEG, observed/expected dry matter intake (DMI), or observed/expected ADG. GH inclusion increased (linear effect, P = 0.01) DMI. Observed DMI for all treatments was approximately 15% to 17% less than anticipated based upon steer growth performance and tabular NE values. Evaluation of observed/expected ADG was 31% to 37% greater than expected for the steers in the present study. Particles less than 4 mm increased (linear effect, P = 0.01) and greater than 4 mm decreased (linear effect, P = 0.01) as GH replaced corn silage in the receiving diet. As the proportion of particles greater than 4 mm increased, cumulative ADG was decreased. These data indicate that GH should be considered in corn silage-based receiving diets to improve DMI. In high-risk calves, improved DMI could result in a lesser incidence of morbidity, although no morbidity was observed in any steers from the present study.

scholarly journals 450 Late-Breaking: Effects of bedding on feedlot receiving phase growth performance in beef steers during the winter in eastern South Dakota

2019 ◽  
Vol 97 (Supplement_3) ◽  
pp. 141-142
Author(s):  
Dathan Smerchek ◽  
Zachary K Smith
Keyword(s):  
Metabolic Rate ◽  
South Dakota ◽  
Growth Performance ◽  
Block Design ◽  
Average Daily Gain ◽  
Experimental Unit ◽  
Beef Steers ◽  
Phase Growth ◽  
Randomized Complete Block Design ◽  
Daily Gain

Abstract Two-hundred and forty English × Continental beef steers (initial BW=365 kg [SD 22.5]) were used in a randomized complete block design to evaluate the effects of bedding application during a 36 d feedlot receiving phase on growth performance and efficiency during winter. Steers were allotted to 30 pens (n = 8 steers/pen) at the Ruminant Nutrition Center in Brookings, SD and pens were assigned to 1 of 2 treatments: 1) No bedding applied (NO) or 2) 1.8 kg (as-is basis) of wheat straw bedding/steer/d (BED). Due to the logistics of acquiring, weighing, and timely feeding of steers, the first 9 pen replicates began on test 14 d prior (begin: January 15, 2019 and end: February 20, 2019) to the last 6 pen replicates (begin: January 29, 2019 and end: March 6, 2019). Pen was the experimental unit; an α of 0.05 determined significance. Daily ambient temperature (n = 50) averaged -14.7°C [SD 5.63] and wind-chill (n = 50) averaged -17.7°C [SD 6.40]. Initial BW (365 vs. 365 ± 0.5 kg) and dry matter intake (8.19 vs. 8.22 ± 0.047 kg) did not differ (P ≥ 0.57) between NO and BED. End BW was greater for BED (P = 0.01; 419 vs. 402 ± 1.09 kg) compared to NO. Steers from BED had increased average daily gain (P = 0.01) by 48.0% and gain:feed (P = 0.01) by 49.2% over NO. Using tabular ingredient energy values and observed steer performance shrunk 4%, relative adjustments to metabolic rate were calculated. Estimated metabolic rate was elevated (P = 0.01) for NO (0.146 vs. 0.104 ± 0.0032 Mcal/BW0.75, kg). Bedding improves feedlot receiving phase growth and efficiency in eastern South Dakota during the winter. Under the environmental conditions of this experiment, steers have a 40.4% increased metabolic rate when bedding is not used and steers in bedded pens had a 35.1% increase in metabolic rate compared to (0.077 Mcal/BW0.75, kg).

scholarly journals 294 Effects of bedding application on growth performance and carcass traits in finishing beef steers during the winter and spring in eastern South Dakota

2020 ◽  
Vol 98 (Supplement_3) ◽  
pp. 143-143
Author(s):  
Dathan Smerchek ◽  
Zachary K Smith
Keyword(s):  
South Dakota ◽  
Growth Performance ◽  
Dry Matter ◽  
Block Design ◽  
Concrete Surface ◽  
Dry Matter Intake ◽  
Experimental Unit ◽  
Beef Steers ◽  
Phase Growth ◽  
Randomized Complete Block Design

Abstract Two-hundred and forty Continental × English beef steers (allotment BW = 365 kg [SD 22.5]) were used in a randomized complete block design feedlot study to evaluate the effects of bedding application during the finishing phase. Steers were allotted to 30 concrete surface pens (n = 8 steers/pen) at the Ruminant Nutrition Center (RNC) in Brookings, SD. A common diet was fed that contained 2.09 Mcal/kg of NEm and 1.39 Mcal/kg of NEg and provided 30 g/ton of monensin sodium to diet DM. Pens were assigned to 1 of 2 treatments: 1) No bedding applied (NO) or 2) 1.8 kg (as-is basis) of wheat straw bedding/steer/d (BED). The first 9 pen replicates began on test 14 d prior to the last 6 pen replicates. Pen was the experimental unit; an α of 0.05 determined significance. This study was part of a factorial experiment that included steroidal implant. No interactions were detected (P ≥ 0.09). Daily ambient temperature (n = 183) averaged 4.33°C [SD 3.21] during the study. Dry matter intake was increased (P = 0.01) by 5.8% in BED compared to NO. Carcass-adjusted ADG (P = 0.01) and G:F (P = 0.01) were increased in BED by 21.0% and 14.4%, respectively. Carcass-adjusted final BW and HCW tended to differ (P ≤ 0.07) between NO and BED. Cattle from NO required an additional 35 days to achieve similar final live BW. Rib eye area (P = 0.69) did not differ between NO and BED. Dressing percentage (P = 0.01; 63.29 vs. 62.30 ± 0.410%), backfat (P = 0.01; 1.19 vs. 1.09 ± 0.410 cm), marbling (P = 0.01; 475 vs. 437 ± 6.6), and yield grade (P = 0.03; 2.95 vs. 2.81 ± 0.045) were increased in NO. Estimated metabolic rate was elevated (P = 0.02; 0.0995 vs. 0.0948 ± 0.013 Mcal/BW0.75, kg), for NO vs. BED. Bedding improved feedlot finishing phase growth performance and gain efficiency during finishing in eastern South Dakota.

scholarly journals PSXIV-18 Feeding behavior of feedlot steers fed combinations of feed additives

2019 ◽  
Vol 97 (Supplement_3) ◽  
pp. 437-437
Author(s):  
Evandro Dias ◽  
Jhones O Sarturi ◽  
Tosha opheim ◽  
Darren D Henry ◽  
Carly A Hoffmann ◽  
...  
Keyword(s):  
Feeding Behavior ◽  
Block Design ◽  
Random Effect ◽  
Feedlot Cattle ◽  
Feed Additives ◽  
Feed Additive ◽  
Experimental Unit ◽  
Beef Steers ◽  
Single Animal ◽  
The Difference

Abstract The effects of dietary feed additives (single or combination) on feeding behavior of feedlot cattle, and the representativeness of one individual animal within the experimental unit were evaluated. Crossbred-Angus beef steers (n = 240; initial BW = 319 ± 29 kg) were used in an randomized complete block design (block = BW), 4 steers/pen (experimental unit; n = 12/treatment), and randomly assigned to the following treatments: 1) no feed additive; 2) monensin (300 mg/animal-daily) + tylosin (90 mg/animal-daily); 3) monensin + L. salivarius L28 (106 CFU/animal-daily); 4) tylosin; and 5) L. salivarius. Animals were fed (steam-flaked corn-based finishing diet) once-daily (clean-bunk management). Feeding behavior (24 h; 5 min intervals) was measured as time spent in activities. In addition, one steer/pen was individually assessed. The Glimmix procedures of SAS were used for statistical analyses (fixed effect = treatment; random effect = block). Feed additives did not affect time spent eating (163 min/d; P = 0.42); ruminating (71 min/d; P = 0.82); chewing (234 min/d; P = 0.21); drinking (18 min/d; P = 0.59); ruminating/kg of DM (9 min/d; P = 0.75); chewing/kg of DM (30 min/d; P = 0.40); resting (1085 min/d; P = 0.25); or other activities (102 min/d; P = 0.32). The difference between feeding behavior pen average and the value from the single animal marked within the same pen was different from zero for rumination (P ≤ 0.04), eating (P = 0.03), and other activities (P = 0.04), while not different from zero for chewing (P ≥ 0.21), drinking (P ≥ 0.13; except for one treatment P < 0.01), and resting (P ≥ 0.12; tendency exhibited by one treatment P < 0.09). Feed additives seem to not affect feeding behavior half-way-through the finishing phase. One animal within a 4-animal/pen unit did not represent the pen average feeding behavior.

scholarly journals PSII-31 Manipulation of steam-flaked corn bulk density during grain adaptation phase of beef steers: ruminal fermentation characteristics and feeding behavior

2019 ◽  
Vol 97 (Supplement_3) ◽  
pp. 216-216
Author(s):  
Carly A Hoffmann ◽  
Darren D Henry
Keyword(s):  
Feeding Behavior ◽  
Bulk Density ◽  
Block Design ◽  
Adaptation Strategy ◽  
Beef Steers ◽  
Ruminal Fermentation ◽  
Ruminal Ph ◽  
Randomized Complete Block Design ◽  
Ph Probes ◽  
Adaptation Phase

Abstract The effects of steam-flaked corn bulk density (SFC-BD) during grain adaptation phase on ruminal fermentation characteristics and feeding behavior were evaluated. Six crossbred ruminally-cannulated Angus beef steers (BW = 404 ± 42 kg; experimental units) were used in a randomized complete block design (block = BW). Steers were assigned to adaptation strategy grain-treatment: a) SFC-BD of 335g/L (335); or b) 412g/L (412). Steers were fed ad-libitum during six 7d phases consisting of: HAY; step-up (1, 2, 3, and 4); and a common 335 SFC-BD FINISHER diet. Respective SFC-BD treatments were fed throughout step-up diets. Ruminal pH was continuously measured (wireless pH probes), and ruminal fluid collected for further analyses. A continuous observation (24h) was used for feeding behavior. Data were analyzed using GLIMMIX procedures of SAS. SFC-BD did not affect (P ≥ 0.19) measured variables, except for increasing NDF (P < 0.01) and tending to increase (P = 0.09) ADF digestibility for 412 steers during step-up 2 and 3. Steers fed 412 had greater (P ≤ 0.05) DMI during step-up 3 and 4 compared to FINISHER. Greater (P ≤ 0.01) digestible DMI during step-up 4 and FINISHER were observed compared to other phases. Digestible NDF/ADF intakes were greatest (P ≤ 0.05) during HAY-phase. Digestibility of DM was lowest (P ≤ 0.05) during HAY-phase. Steers ruminated more (P ≤ 0.05) during HAY-phase than FINISHER. Chewing was greatest (P ≤ 0.05) for HAY and intermediate for Step-up 1. Ruminal C2:C3 decreased (P < 0.01) as steers advanced through phases. Ruminal ammonia-N was greatest (P < 0.01) for step-up 1 and 2, and intermediate for other phases. The SFC-BD range studied seemed to not dramatically affect ruminal fermentation characteristics and feeding behavior. The most critical moment evidenced was between HAY and the receiving diet, as well as, when 412 g/L was suddenly switched to 335 g/L.

scholarly journals PSVI-17 Effects of increasing doses of trenbolone acetate and estradiol on sera metabolites following implantation during the finishing phase in beef steers

2020 ◽  
Vol 98 (Supplement_3) ◽  
pp. 217-217
Author(s):  
Dathan Smerchek ◽  
Zachary K Smith
Keyword(s):  
Block Design ◽  
Experimental Unit ◽  
Beef Steers ◽  
Ruminant Nutrition ◽  
Trenbolone Acetate ◽  
Factor I ◽  
Randomized Complete Block Design ◽  
Igf I ◽  
Estradiol 17Β ◽  
Post Implantation

Abstract Continental × English crossbred beef steers (n = 240; allotment BW = 365 kg [SD 22.5]) were used in a randomized complete block design feedlot study designed to evaluate the effects that increasing doses of trenbolone acetate (TBA) and estradiol-17β (E2) have on sera urea-N (SUN) and sera insulin-like growth factor I (IGF-I). Steers were allotted to 30 pens (n = 8 steers/pen) at the Ruminant Nutrition Center (RNC) in Brookings, SD; and were then assigned to 1 of 3 treatments: 1) No implant (NI), 2) Synovex Choice [100 mg TBA + 10 mg E2; CH], or 3) Synovex Plus [200 mg TBA + 20 mg E2; PL] administered 124 days before harvest. This study was part of a factorial experiment that included bedding application. No interactions were detected (P ≥ 0.26). Blood samples were collected and harvested as sera during the weighing process on d 1, 28, 56, and 84 prior to feeding from sentinel steers (n = 2 steers/pen) and pen served as the experimental unit. An implant × day interaction (P = 0.05) was noted for SUN. On d 28, NI cattle had the greater SUN (P = 0.05) compared to PL and CH was intermediate to NI and PL. No implant × day interaction (P = 0.52) was detected for sera IGF-I. However, sera IGF-I was increased (P = 0.01) 14.7% and 18.7% for CH and PL respectively compared to NI. Sera IGF-I also increased as days on feed increased (P = 0.01). Increasing doses of TBA and E2 resulted in increased anabolism as indicated by a reduction in SUN 28 d after implantation and increased sera IGF-I post-implantation.

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