Prediction of Mature Cow Carcass Composition from Live Animal Measurements

Abstract

Two trials were conducted with mature cows to develop prediction equations for estimating carcass composition from live animal measurements. Trial 1 involved 82 animals that were used to develop these equations. Subjective criteria (frame and condition scores) also were utilized along with live weight in development of prediction equations. Equations using subjective independent variables predicting energy and carcass tissue weights apparently were slightly more variable in precision (R2 = .69 to .91) than those developed with objective variables (R2 = .74 to .90). Equations predicting percent compositions from subjective variables had lower coefficients of determination (R2 = .49 to .76) than those developed with objective variables (R2 = .63 to .83). Forty-one animals similar to those used in Trial 1 served as a test group in Trial 2. Measured carcass composition was regressed on composition predicted by equations developed in Trial 1. These equations generally had slopes and intercepts with confidence intervals that included 0 and 1, respectively, indicating that most of the prediction equations were unbiased. This work indicates that carcass composition can be predicted from both objective and subjective measurements, with some accuracy and precision.

Auction prices, market share, and a common agent

“…Prin5 purchased the heaviest cull cows (1602.64 pounds) at the highest average price ($40.77/cwt), while CBA purchased the lightest animals (1095.57 pounds) on behalf of Prin1 at an average price of ($26.61/cwt). These price-weight relationships are expected, because heavier cows tend to yield more red meat and higher valued cuts of meat (O'Mara et al, 1998;Gresham et al, 1986).…”

“…We rely on the significant correlation between the observable and other physiological indicators unobserved to the econometrician from which the buyer derives a signal of the animal's true carcass characteristics (O'Mara et al, 1998;Mintert et al, 1990;Gresham et al, 1986). For instance, a cubic live weight relationship best explains the relationship between live weight and price because extremely light (heavy) cows receive greater discounts (premiums) due to disproportionally lower (higher) total red meat yield and yield of low (high) valued cuts of meat.…”

“…However, cull cow carcasses are heterogeneous as to their individual contribution of total meat, categories and quality of meat products. Because cull cows are sold live, bidders must rely on a set of imperfect signals of each animal's true aggregate output value via visual appraisal of the animal's observable physiological attributes (O'Mara et al, 1998;Gresham et al, 1986). Each animal's true carcass value is common to symmetric processors, because the components of the carcass within quality specifications are also uniform in value (United States Department of Agriculture, Agricultural Marketing Service).…”

Composição tecidual do lombo de ovelhas de descarte terminadas em confinamento e abatidas em diferentes estágios fisiológicos

“…A gordura subcutânea apresentou correlação alta (correlação positiva) com a quantidade de gordura comestível e correlação negativa (P<0,01) com a relação músculo:osso e com a quantidade de músculo do lombo, estando de acordo com o descrito por Gresham et al (1986).…”

Composição física da carcaça e qualidade da carne de vacas de descarte de diferentes grupos genéticos terminadas em confinamento com distintos pesos

“…Embora o peso absoluto do tecido ósseo tenha se mantido constante nos diferentes pesos de abate, sua participação percentual decresceu, com reflexo do aumento do tecido muscular e, sobretudo, do adiposo. Esse comportamento dos três tecidos com o aumento do peso de abate dos animais já é muito tempo conhecido (Berg & Butterfield, 1976, em trabalhos com novilhos e novilhas) e foi confirmado por Gresham et al (1986), em estudos com vacas de descarte.…”