Estrogen Implants Reduce Carcase Value
US - Conventional US cattle-production systems are designed to provide consumers with a consistent supply of high-quality, grain-fed beef, which is preferred in current mainstream US beef markets (both domestic and export).
22 December 2011
2 minute read
The majority of cattle produced for US mainstream beef markets are grain-finished steers and heifers harvested at 12 to 24 months of age.
At these young ages, steers and heifers are expected to produce A-maturity carcasses when they are graded by USDA and, yet, some of these cattle exhibit sufficient degrees of skeletal ossification to cause their carcases to be classified as B-maturity or older, which significantly reduces carcase value and marketability.
Skeletal ossification is accelerated by high levels of estrogen, so heifers typically show more advanced skeletal maturity than do steers of the same age. In females, increased estrogen levels associated with pregnancy, parturition, and lactation further promote skeletal maturation.
Moreover, cattle that have been treated with estrogen-containing implants tend to produce carcases with skeletal characteristics that are physiologically more mature than carcasses produced by cattle that have not received estrogenic implants.
The effect of implanting on skeletal maturation appears to be dependent upon the estrogenic dose delivered by the implant, the number of estrogen-containing implants that an animal receives prior to slaughter, and age of the animal.
Sequentially implanted cattle, particularly heifers, greater than 20-months old are most likely to produce B-maturity or older carcasses. Though it is not well documented in the scientific literature, it is possible that premature skeletal ossification in cattle also may be linked with unintentional exposure of cattle to diets containing estrogenic compounds, such as those produced by certain forage plants (phytoestrogens) or by fungi (mycoestrogens) that infect forages and grains.
Additional research would be required to determine what, if any effect, premature skeletal ossification has on eating quality (particularly tenderness) of beef produced by steers and heifers known to be less than 30-months old.
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