213 Assessment of Equations Relating Shrunk, Empty Body, and Carcass Weight in Growing/Finishing Cattle

Abstract

Abstract Existing equations to estimate empty body weight of cattle from live or carcass weight were developed over 40 years ago using different cattle genetics. The objective of this analysis was to evaluate existing equations using cattle genetics from that time to today. A literature search was performed to identify experiments measuring shrunk body weight (SBW), empty body weight (EBW), and carcass weight (HCW) resulting in 269 treatment means from 32 experiments since 1976. Two equations were used to compute EBW from SBW: 1) NASEM (2016) and 2) Gil et al. (1970: 10.2527/jas1970.313459x). Eight equations were used to compute HCW from EBW: 1) Lofgreen et al. (1962; 10.2527/jas1962.21120x), 2) Garrett and Hinman (1969; 10.2527/jas1969.2811), 3) Holzer and Levy Eq. 1 (1969; Isr. J. Agric. Res. 19:195), 4) Holzer and Levy Eq. 2, 5) Gil et al. (1970: 10.2527/jas1970.313459x), 6) Alhassan et al. (1975; 10.4141/cjas75-045), 7) Ferrell et al. (1976; 10.2527/jas1976.4251158x), and 8) Fox et al. (1976; 10.2527/jas1976.433566x). Mean (SD) shrunk, empty, and carcass weight were 359 (145), 322 (134), and 210 (92) kg, respectively, and were strongly correlated (> 0.990). For all equations, simultaneous testing of intercept equal to zero and slope equal to 1 indicated that the intercept and slope for EBW and HCW were different than zero and one, respectively. For EBW, the CCC was high (> 0.95) for all equations and mean bias was -1.69 and -4.75% for Eq. 1 and 2, respectively, but became a greater underprediction in more recent publication years for Eq. 1. For HCW, CCC was high (> 0.95) and similar for all equations, but Eq. 7 had the MB nearest to zero (-0.10%) and Eq. 4 furthest from zero (10.74%). For Eq. 2, 4, 6, and 8 there was greater overprediction in more recent publication years. In conclusion, existing equations provide similar precision, but differ in accuracy to predict weight with some equations significantly influenced by year of publication.