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BRIEF RESEARCH REPORT article

Front. Anim. Sci.

Sec. Animal Nutrition

Performance assessment of feedlot cattle receiving two or three implants

Provisionally accepted
Jorge HidalgoJorge Hidalgo1José G. García MuñízJosé G. García Muñíz2*Mondina F. LunesuMondina F. Lunesu3Alberto CesaraniAlberto Cesarani3Alberto Stanislao AtzoriAlberto Stanislao Atzori3Marco A. EspinoMarco A. Espino4Roberto SalcedoRoberto Salcedo5Eric ToledoEric Toledo2John Michael GonzalezJohn Michael Gonzalez1
  • 1University of Georgia, Athens, United States
  • 2Universidad Autonoma Chapingo, Texcoco, Mexico
  • 3Universita degli Studi di Sassari, Sassari, Italy
  • 4Corrales el 3, Belem, Mexico
  • 5Nutrientes Básicos de Monterrey, SA de CV, Monterrey, Mexico

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Forty-five pens were randomly assigned to one of two implant strategies (2 or 3 implants) in a randomized complete block experimental design. Each pen had 60 bulls with average initial weight of 277.6 ± 8.1 kg (ranging from 255 to 289 kg) and was fed for 180 days. Bulls were implanted (100 mg trenbolone acetate – 14 mg 17-β estradiol benzoate; Synovex® Choice) starting the experiment and reimplanted (200 mg trenbolone acetate – 20 mg 17-β estradiol; Revalor® H) after 90 (two implants; Synovex® Choice – Revalor® H) or 60 and 120 (three implants; Synovex® Choice – Revalor® H – Revalor® H) days on feed. Measured performance indicators were average daily gain (ADG), dry matter intake (DMI), and feed efficiency expressed as the ratio gain to feed (G:F) or feed conversion ratio (FCR). Linear mixed model analyses included the treatment (implant strategy) and the covariate average initial weight as fixed effects and block (two-week feedlot entry period) as random effect. Treatment affected all performance measures (P < 0.01) but ADG (P = 0.08). Pens of cattle administered two implants had greater (P < 0.01; 9.54 ± 0.09 vs. 9.16 ± 0.10 kg•d-1) DMI than pens of cattle administered three implants. Pens of cattle administered three implants had greater (P < 0.01; 0.160 ± 0.002 vs. 0.172 ± 0.002) G:F and smaller (P < 0.01; 6.25 ± 0.08 vs. 5.82 ± 0.08) FCR than pens of cattle administered two implants.

Keywords: average dailygain, beef cattle, Dry matter intake, feed efficiency, growth-promoting anabolic, Re-implant

Received: 18 Aug 2025; Accepted: 08 Dec 2025.

Copyright: © 2025 Hidalgo, García Muñíz, Lunesu, Cesarani, Atzori, Espino, Salcedo, Toledo and Gonzalez. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

* Correspondence: José G. García Muñíz

Disclaimer: All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers. Any product that may be evaluated in this article or claim that may be made by its manufacturer is not guaranteed or endorsed by the publisher.

Supplementary Material