Effects of delayed implant protocols on performance carcass

Effects of delayed implant protocols on performance, carcass characteristics and meat tenderness in Holstein steers J. L. Beckett, and J. Algeo Cal Poly State University Algeo Consulting

Strategies u Approximately 20 implants approved for use in cattle u Tremendous number of combinations possible u Producers need to establish strategies that best utilize the advantages of the different implants u Long-fed cattle are particularly subjected to repetitive implant regimens

Effects u Increase frame size – Increases growth curve u Decrease quality grade – Lower % Choice – Due to change in physiological endpoint u Increases muscling u Effect on tenderness?

Implant Protocol Ralgro Treatment Groups A Ralgro Syn-S Revalor-S B Synovex-C Syn-S Revalor-S C Synovex-C Rev-IS Revalor-S D Revalor-G Rev-IS Revalor-S No Implant E 0 60 120 180 291

Average Daily Gain

Final Weight

Gain to Feed

Percentages of Holstein steer carcasses grading USDA Choice or better

USDA Yield Grade

Project Summary u Goal: Identify the time that implants can be initiated to: – Capture maximal growth and performance – Minimize detrimental effects on product u 186 steers on feed for 280 d – Initial weight 156 kg u Weighed every 30 days § At the end of the feeding phase, animals were harvested and carcass data collected

Diet

Average Finishing Ration Analysis u Dry matter 84% u Crude Protein 12. 79% u NEg 1. 23 Mcal/kg u NEm 1. 95 Mcal/kg

Experimental Protocol

Final Weight

Average Daily Gain

Feed to Gain

Longissimus Muscle Area

Percentages of Holstein steer carcasses grading USDA Choice or better a ab abc bc c

USDA Yield Grade

Meat u Ribs aged for 14 days u 2 steaks from each rib were removed, individually vacuum packed u Steaks sent to Colorado State University u CSU measured tenderness (shear force) and conducted trained taste panel

Warner-Bratzler Shear Force

WB Shear Force over 5

Trained Taste Panel a ab ab bc c

Summary u Early implants dramatically influence marbling at a given weight u Delaying implants tend to improve marbling without significant effects on growth & efficiency u Aggressive nature of implant strategy should complement the market u Variations in tenderness can not be explained by the use of implants

Percent Empty Body Fat

Percent Empty Body Fat a ab b b ab

Adjusted Final Body Weight a a b

AFBW from nonimplanted Controls