Scientists predict the future of cattle feed intake

New equations for body weight gain and energy use in heifers and steers could make feeding systems more efficient, according to researchers from Texas Tech University and Texas A&M. The findings reveal a more accurate way to use feed-lot databases to predict feed intake by cattle and customize feed individual pens. The study was published May 7 in the Journal of Animal Science.

McMeniman et al. used data from 3,363 pens from three feedlots over a 4-year period between 2003 and 2006. By analyzing the initial and final body weights of cattle, they determined that the sex, initial body weight of the animal, and antibiotics that promote growth affect the amount of dry matter (dry food; DM) that they eat, including corn and other grains. For example, nutritionists could use equations that factor in the sex of the animal to improve predictions for DM intake (DMI), since heifers mature faster than steers, they reach final body weight sooner and require less DM to reach mature size. To increase efficiency and costs of production, it is important for managers of feedlots to predict the right amount of feed to give cattle to reach the target body weight.

These findings reveal limitations of the equations currently used by the National Research Council (NRC) for the net energy required for cattle. The researchers found that the NRC data were limited by the lack of accurate body weight predictions for cattle.

Because factoring in the use of growth enhancers, like monensin and tylosin, could improve the accuracy of DMI predictions, the researchers promote the use of “in-house DMI predictions”. The researchers believe their equations can be combined with NRC predictions for most accurate DMI estimates. Sex, initial body weight, and use of growth promotants are factors that feedlot-managers can incorporate into NRC predictions to improve DMI estimates.

The team used data from feedlots in Oklahoma, Texas, and New Mexico, so the equations they developed for predicting DMI would likely be most in feedlots in the Southern Plains region of the U.S. The researchers suggest that future studies should set a target body weight for cattle and then follow DMI predictions to test the accuracy of the system. “The usefulness of such predictions tailored to individual feedlots also likely relies on consistency of marketing animals at the specified target endpoint [body weight],” wrote McMeniman et al. They also recommend that future studies investigate the affect of various growth promotants.

The project was funded by the Jesse W. Thornton Chair in Animal Science Endowment at Texas Tech University. The paper is entitled “Development and evaluation of feeding-period average dry matter intake prediction equations from a commercial feedlot database,” and can be found in full at journalofanimalscience.org.

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