1. 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

2. 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

3. 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?

4. Implant Protocol No Implant Ralgro Revalor-S Synovex-CSyn-S Rev-IS Revalor-G 060120180291 Treatment Groups A B C D E RalgroSyn-S Revalor-S Synovex-C

5. Average Daily Gain

6. Final Weight

7. Gain to Feed

8. Percentages of Holstein steer carcasses grading USDA Choice or better

9. USDA Yield Grade

10. Discussion u Implants: –Increased average daily gains, –Improved feed efficiency –Increased daily dry matter intake –Heavier hot carcass weights –Larger longissimus muscle area u Early implants dramatically influence growth curves u Aggressive estrogens suppressed marbling resulting in lower quality grades

11. 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

12. Diet

13. Average Finishing Ration Analysis u Dry matter 84% u Crude Protein 12.79% u NE g 1.23 Mcal/kg u NE m 1.95 Mcal/kg

14. Experimental Protocol

16. Final Weight

17. Average Daily Gain

18. Daily Dry Matter Intake

19. Feed to Gain

20. Longissimus Muscle Area

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

22. USDA Yield Grade

24. 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

25. Warner-Bratzler Shear Force

26. WB Shear Force over 5

27. Trained Taste Panel ab bc c a

28. 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

30. Percent Empty Body Fat

31. a ab b b

32. Adjusted Final Body Weight a a a a b

33. AFBW from nonimplanted Controls