1 / 74

Stocker Programs, Feedlot Performance and Carcass Merit

Stocker Programs, Feedlot Performance and Carcass Merit. Jim Oltjen University of California, Davis April 10, 2008. UC Sierra Foothills Research & Extension Center. UC Davis Feedlot. Outline. Compensatory growth Using Davis Growth Model for performance and carcass traits

lynton
Download Presentation

Stocker Programs, Feedlot Performance and Carcass Merit

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  1. Stocker Programs, Feedlot Performance and Carcass Merit Jim Oltjen University of California, Davis April 10, 2008

  2. UC Sierra Foothills Research & Extension Center

  3. UC Davis Feedlot

  4. Outline • Compensatory growth • Using Davis Growth Model for performance and carcass traits • Growing phase feed quality effects • Growing phase length effects • Previous nutrition effects on carcass merit and maintenance • Physiology of growth and fat development • Latest Research on: • Patterns of marbling • Length of stocker phase effects on fat distribution • Length of stocker phase effects on rate of marbling and subQ fat gain • Residual feed intake relationship with maintenance requirements • New model to predict fat distribution

  5. Compensatory growth in beef cattle From: Sainz et al., 1995

  6. Compensatory gain in feedlot steers Sainz et al., 1995

  7. Compensatory gain in feedlot steers Sainz et al., 1995

  8. Compensatory gain in feedlot steers Sainz et al., 1995

  9. Davis Growth Model Net energy Ttrtrttr Rtrttr r Fat (kg) Maintenance Protein

  10. Davis Growth Model (Oltjen et al. 1986) Biological processes: Cell proliferation and hypertrophy Homeorrhetic control Metabolizable Energy Intake Biological processes: Synthesis and degradation Heat production Biological processes: maintenance Efficiency of conversion into net energy is related to both quantity and concentration of metabolizable energy in the diet

  11. Effect of diet quality in growing phase to a constant BW endpoint (327 kg)

  12. Stocker cattle’s rate of gain is linear from 2 to 3 Mcal ME/kg DM assuming cattle are fed ad libitum or have adequate available forage.

  13. (growing phase to 327 kg BW)

  14. Finishing daily gain is inversely and nearly linearly related to previous growing phase performance.This hardly varied whether cattle were fed to equal body weight or fat content endpoints.

  15. (growing phase to 327 kg BW)

  16. Steers fed to an equal body weight endpoint were more sensitive to previous growing phase ration energy compared to steers fed to a constant fat endpoint. Those fed higher energy diets as calves reached acceptable carcass fatness at much lighter weights.

  17. Effect of growing phase length(MEC = 1.87 Mcal/kg)

  18. Finishing period performance (growing phase MEC 1.87 Mcal/kg)

  19. Finishing period performance (growing phase MEC 1.87 Mcal/kg)

  20. (growing phase MEC 1.87 Mcal/kg)

  21. Steers fed to an equal body weight endpoint were more sensitive to the length of the growing period compared to a constant fat endpoint.

  22. Calf fed’s reach carcass fatness before desirable slaughter weights, confirming previous work that medium or small frame steers require a growing period before slaughter, particularly if not implanted.

  23. Calf fed’s reach carcass fatness before desirable slaughter weights, confirming previous work that medium or small frame steers require a growing period before slaughter, particularly if not implanted. Conversely, if we use longer growing periods due to increased cost of grain, cattle will have to be fed to larger weights for acceptable fatness, further exacerbating the progressive trend to larger carcasses in the industry.

  24. Intermuscular Fat Subcutaneous Fat Intramuscular Fat

  25. Compensatory growth in beef cattle a a a b b a a a b b a ab b c c From: Sainz et al., 1995

  26. Compensatory growth in beef cattle a a ab ab b a ab b ab b a ab ab b b From: Sainz et al., 1995

  27. Compensatory gain in feedlot steers Sainz et al., 1995

  28. Compensatory gain in feedlot steers Sainz et al., 1995

  29. Compensatory gain in feedlot steers SEM a b b Sainz et al., 1995

  30. Growth curves

  31. Allometric growth

  32. Frame score and total body fat

  33. Growth gradients among adipose depots

  34. From: Bruns et al. (2004) J. Anim. Sci. 82:1315-1322

  35. UC Sierra Foothills Research & Extension Center

  36. From: Sainz & Vernazza-Paganini, 2004

  37. From: Sainz & Vernazza-Paganini, 2004

  38. From: Sainz & Vernazza-Paganini, 2004

  39. UC Sierra Foothills Research & Extension Center

  40. Gain in 12th rib fat gain (BF. µm/day) in high and low growth cattle backgrounded at two ME levels

  41. Gain in intramuscular fat gain (IMF. %/day) in high and low growth cattle backgrounded at two ME levels

  42. UC Davis Feedlot

  43. Residual Feed Intake • More efficient steers with negative RFI ate less (12%). • RFI was related to maintenance energy requirements (r=0.42). • No ‘significant’ association with carcass traits. • Myofibrillar protein degradation rates were positively related to maintenance energy requirements (r=0.76), but were not related to RFI (r=-0.14). A genetic trait related to RFI should be used in prediction models to account for differences in maintenance. Eventually adjust for protein synthesis/degration rate differences which are explicitly represented in the Davis Growth Model.

  44. Intermuscular Fat Subcutaneous Fat Intramuscular Fat

More Related