Thesis Title

Effect Of Different Implant Regimes On The Accuracy Of Ultrasound For Prediction Of Body Composition Characteristes In Beef Cattle

Author

Brock Frieden

Date of Graduation

Spring 2002

Degree

Master of Natural and Applied Science in Agriculture

Department

College of Agriculture

Committee Chair

Thomas Perkins

Subject Categories

Agriculture

Abstract

The objective of this study was to examine the effect of different implant regimes on the accuracy of ultrasound for the estimation of body composition characteristics in beef cattle. Ultrasonic measurements of longissimus muscle (ribeye) area (REAU), 12th-rib fat thickness (FTU), and percent intramuscular fat (PFATU) were taken by one technician. Cattle were harvested at 110 d (n=21), 141 d (n=3), 160 d (n=25), 180 d (n=25), 201 d (n=25), 208 d (n=22) and 258 d (n=24) after being scanned. Carcass measurements included: hot carcass weight (HCW), longissimus muscle (ribeye) area (REA), fat thickness at the 12th rib (FT), preliminary yield grade (PYG), kidney, pelvic, and heart fat (KPH), marbling score (MS), final yield grade (YG), and final quality grade (QG). All crossbred steers (n=145) were scanned ultrasonically and implanted on the same day. One of four implant regimes were administered in a completely randomized design as follows: control (n=37) with no implant (TRT1) ; Ralgro® (n=32) (zeranol, 36 mg; Scherining-Plough, Union, NJ) (TRT2); Revalor® (n=36) (24 mg estradiol, 120 mg trenbolone acetate; Hoechst Roussel Vet., Warren, NJ) (TRT3); and double Revalor® (n=40) (TRT4) implant. Means by treatment for FT, REA, MS, FTU, REAU, PFATU, and CPFAT were 1.08 cm, 95.18 cm², 5.30, .59 cm, 64.43 cm², 3.38%, 3.09% (TRT1); 1.10 cm, 93.70 cm², 5.16, .58 cm, 64.04 cm², 3.36%, 3.18% (TRT2); 1.05 cm, 94.79 cm², 5.14, .51cm, 63.14 cm², 3.30%, 3.14% (TRT3); .85cm, 96.85 cm², 4.96, .54 cm, 63.21 cm², 3.28%, 3.10% (TRT4) respectively. Correlations between FTU and FT by treatment were .61, .64, .69, and .54 for each implant regime. Correlations between REAU and REA by treatment were .37, .56, .35, and .46 for each implant regime. Correlations between PFATU and MS by treatment were .35, .13, .42, and .38 for each implant regime. Correlations between CPFAT and MS by treatment were .30, .08, .45, and .42 for each implant regime. Theses data suggest that ultrasound accuracy was affected by different implant regimes. Implant treatment affected accuracy of fat prediction less than it did accuracy of muscle area or marbling.

Copyright

© Brock Frieden

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