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Effects of ractopamine hydrochloride on nutrient digestibility and nitrogen excretion of finishing beef cattle
The objective was to quantify the effects of the beta-adrenergic agonist (β-AA) ractopamine hydrochloride (Actogain, Zoetis, Parsippany, NJ) on nitrogen excretion and nutrient digestibility in feedlot cattle. In experiment 1, 12 Simmental × Angus steers were blocked by bodyweight (531 ± 16 kg) and u...
Autores principales: | , , , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
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Oxford University Press
2021
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Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8628867/ https://www.ncbi.nlm.nih.gov/pubmed/34853827 http://dx.doi.org/10.1093/tas/txab036 |
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author | Harsh, Bailey N Klatt, Brady J Volk, Mareah J Green-Miller, Angela R McCann, Joshua C |
author_facet | Harsh, Bailey N Klatt, Brady J Volk, Mareah J Green-Miller, Angela R McCann, Joshua C |
author_sort | Harsh, Bailey N |
collection | PubMed |
description | The objective was to quantify the effects of the beta-adrenergic agonist (β-AA) ractopamine hydrochloride (Actogain, Zoetis, Parsippany, NJ) on nitrogen excretion and nutrient digestibility in feedlot cattle. In experiment 1, 12 Simmental × Angus steers were blocked by bodyweight (531 ± 16 kg) and used in a randomized complete block design. Dietary treatments included: 1) a control without β-AA (CON) or 2) 400 mg/steer/d ractopamine hydrochloride (RAC) for 35 d before slaughter. Diets contained (DM basis) 55% dry-rolled corn, 20% corn silage, 15% modified wet distillers grains with soluble, and 10% supplement. For each block, total collection of feed, orts, feces, and urine were conducted for two 5 d sampling periods during week 2 and 4 of RAC supplementation. No interaction (P > 0.21) between treatment and collection period was observed for any parameter evaluated. Dietary treatment had no effect (P = 0.51) on DMI, but RAC had decreased fecal DM output (P = 0.04) compared with CON. Thus, RAC had greater apparent total tract DM digestibility (77.2 vs. 73.5%; P < 0.01), N digestibility (72.4 vs. 69.4%; P = 0.01), and NDF digestibility (65.6 vs. 60.2%; P < 0.01) than CON. Although treatment did not affect nitrogen intake (P = 0.52), RAC tended to reduce total nitrogen excretion (113.3 vs. 126.7 g/d; P = 0.10) compared with CON due to a tendency for decreased fecal nitrogen output (53.9 vs. 61.3 g/d; P = 0.10). However, dietary treatment had no effect (P = 0.53) on urinary nitrogen output or percentage of urinary nitrogen excreted as urea (P = 0.28). Experiment 2 was an in vitro experiment conducted to validate the effects of RAC on nutrient digestibility using Simmental × Angus heifers (451 ± 50 kg). Rumen fluid was collected individually by stomach tube from CON- (n = 9) and RAC-fed (n = 10) heifers to inoculate bottles containing a CON or RAC-containing substrate in a split–plot design. No interaction between rumen fluid source and in vitro substrate was observed. Greater IVDMD (P = 0.01) was observed in rumen fluid from RAC-fed heifers compared with rumen fluid from CON-fed heifers. The inclusion of RAC in the in vitro substrate increased IVDMD (P < 0.01). Overall, feeding RAC increased microbial digestion of the dry-rolled corn-based finishing diet to increase total tract dry mater digestion by 5% and reduce nitrogen excretion by 10.6% in the 35 d period prior to slaughter. |
format | Online Article Text |
id | pubmed-8628867 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2021 |
publisher | Oxford University Press |
record_format | MEDLINE/PubMed |
spelling | pubmed-86288672021-11-30 Effects of ractopamine hydrochloride on nutrient digestibility and nitrogen excretion of finishing beef cattle Harsh, Bailey N Klatt, Brady J Volk, Mareah J Green-Miller, Angela R McCann, Joshua C Transl Anim Sci Ruminant Nutrition The objective was to quantify the effects of the beta-adrenergic agonist (β-AA) ractopamine hydrochloride (Actogain, Zoetis, Parsippany, NJ) on nitrogen excretion and nutrient digestibility in feedlot cattle. In experiment 1, 12 Simmental × Angus steers were blocked by bodyweight (531 ± 16 kg) and used in a randomized complete block design. Dietary treatments included: 1) a control without β-AA (CON) or 2) 400 mg/steer/d ractopamine hydrochloride (RAC) for 35 d before slaughter. Diets contained (DM basis) 55% dry-rolled corn, 20% corn silage, 15% modified wet distillers grains with soluble, and 10% supplement. For each block, total collection of feed, orts, feces, and urine were conducted for two 5 d sampling periods during week 2 and 4 of RAC supplementation. No interaction (P > 0.21) between treatment and collection period was observed for any parameter evaluated. Dietary treatment had no effect (P = 0.51) on DMI, but RAC had decreased fecal DM output (P = 0.04) compared with CON. Thus, RAC had greater apparent total tract DM digestibility (77.2 vs. 73.5%; P < 0.01), N digestibility (72.4 vs. 69.4%; P = 0.01), and NDF digestibility (65.6 vs. 60.2%; P < 0.01) than CON. Although treatment did not affect nitrogen intake (P = 0.52), RAC tended to reduce total nitrogen excretion (113.3 vs. 126.7 g/d; P = 0.10) compared with CON due to a tendency for decreased fecal nitrogen output (53.9 vs. 61.3 g/d; P = 0.10). However, dietary treatment had no effect (P = 0.53) on urinary nitrogen output or percentage of urinary nitrogen excreted as urea (P = 0.28). Experiment 2 was an in vitro experiment conducted to validate the effects of RAC on nutrient digestibility using Simmental × Angus heifers (451 ± 50 kg). Rumen fluid was collected individually by stomach tube from CON- (n = 9) and RAC-fed (n = 10) heifers to inoculate bottles containing a CON or RAC-containing substrate in a split–plot design. No interaction between rumen fluid source and in vitro substrate was observed. Greater IVDMD (P = 0.01) was observed in rumen fluid from RAC-fed heifers compared with rumen fluid from CON-fed heifers. The inclusion of RAC in the in vitro substrate increased IVDMD (P < 0.01). Overall, feeding RAC increased microbial digestion of the dry-rolled corn-based finishing diet to increase total tract dry mater digestion by 5% and reduce nitrogen excretion by 10.6% in the 35 d period prior to slaughter. Oxford University Press 2021-03-07 /pmc/articles/PMC8628867/ /pubmed/34853827 http://dx.doi.org/10.1093/tas/txab036 Text en © The Author(s) 2021. Published by Oxford University Press on behalf of the American Society of Animal Science. https://creativecommons.org/licenses/by/4.0/This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/ (https://creativecommons.org/licenses/by/4.0/) ), which permits unrestricted reuse, distribution, and reproduction in any medium, provided the original work is properly cited. |
spellingShingle | Ruminant Nutrition Harsh, Bailey N Klatt, Brady J Volk, Mareah J Green-Miller, Angela R McCann, Joshua C Effects of ractopamine hydrochloride on nutrient digestibility and nitrogen excretion of finishing beef cattle |
title | Effects of ractopamine hydrochloride on nutrient digestibility and
nitrogen excretion of finishing beef cattle |
title_full | Effects of ractopamine hydrochloride on nutrient digestibility and
nitrogen excretion of finishing beef cattle |
title_fullStr | Effects of ractopamine hydrochloride on nutrient digestibility and
nitrogen excretion of finishing beef cattle |
title_full_unstemmed | Effects of ractopamine hydrochloride on nutrient digestibility and
nitrogen excretion of finishing beef cattle |
title_short | Effects of ractopamine hydrochloride on nutrient digestibility and
nitrogen excretion of finishing beef cattle |
title_sort | effects of ractopamine hydrochloride on nutrient digestibility and
nitrogen excretion of finishing beef cattle |
topic | Ruminant Nutrition |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8628867/ https://www.ncbi.nlm.nih.gov/pubmed/34853827 http://dx.doi.org/10.1093/tas/txab036 |
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