Sundown feeding may cut skirmishes. Feeding cattle just before sunset reduces the number of fights in feedlots, according to a researcher at the USDA’s Agricultural Research Service (ARS).

Animal behaviorist Julie Morrow-Tesch did periodic, 24-hour surveillance of cattle pens in one of the Texas Panhandle’s 6 million-head capacity feedlots. She found that substituting the usual morning feeding with an evening one almost cut in half the number of aggressive incidents.

For cattle, twilight grazing is instinctive. And in a feedlot pen, cattle redirect that instinct into increased social activity, Morrow-Tesch says. One of these behaviors, bulling behavior, can cost feedlots $70/head for treatment.

. For more information contact Julie Morrow-Tesch, ARS Livestock Issues Research Unit Staff, Lubbock, TX, at 806/742-2826 or e-mail jmorrow@lbk.ars.usda.gov.

Chemicals called essentials oils may do double duty in cattle feedlots – killing pathogens like Escherichia coli and reducing emissions of foul-smelling compounds, according to the ARS.

In lab experiments, as little as 1 gram of the essential oils carvacrol and thymol was used to completely block the formation of foul-smelling volatile fatty acids in ½-liter slurries of cattle feces and urine. Use of either chemical inhibited odors in a slurry for weeks, and each was as effective as using the oils in combination, researchers say.

These essential oils also can reduce the populations of fecal bacteria such as Escherichia coli in slurries, researchers say. The oils also are being tested against E. coli 0157:H7 bacteria and other pathogens in feedlot manure.

In addition to finding ways to minimize odor and decrease the prevalence of foodborne pathogens on livestock headed to slaughter, ARS is researching ways to preserve manure’s value as a fertilizer and reduce emission of global warming gases.

For more information contact Vincent Varel, ARS Roman L. Hruska U.S. Meat Animal Research Center, Clay Center, NE, at 402/762-4207 or e-mail varel@email.marc.usda.gov.

Extending the feeding period to improve the proportion of Choice carcasses may be counterproductive, sacrificing carcass yield for quality, according to researchers at Kansas State University. That’s because backfat seems to increase more rapidly than intramuscular fat.

But, the KSU researchers have found that ultrasound estimates made during the feeding period can be used to predict carcass merit at slaughter. They studied ultrasound technology to find an objective method to determine the number of days that feedlot cattle should be fed a high-concentrate finishing ration.

They used ultrasound to obtain serial measurements of backfat thickness and marbling score for two groups of steers fed high-energy rations 166 and 148 days. The data were used to develop predictions for the number of days on feed necessary for cattle to attain the low Choice grade and/or reach a target backfat level.

Although projections from the initial evaluation date allowed tentative categorization for Choice or not Choice, they were only 64% accurate. But, projections from evaluations made later in the feeding period exceeded 75% accuracy in distinguishing Choice from Select.

For more information contact John Brethour, Kansas State University Agricultural Research Center, Hays, KS, at 785/625-3425 or e-mail jbrethou@ksu.edu.

Feeder research was compiled by Diana Barto at 952/851-4678 or diana_barto@intertec.com.