Most feedlot cattle, on the other hand, are fed in the morning. This means they have nothing to eat in the evening when their instincts are telling them to graze. This could be why they are more aggressive in the early evening, says animal behaviorist Julie Morrow-Tesch. She believes that the nightly pushing and shoving matches that she has witnessed on Texas feedlots "are a substitute for cattle's instinctive twilight grazing." She estimates that these evening melees cost feedlot operators an average of $70 per head. The cost would be even higher if environmental factors were taken into account, she says, because the disruptive behavior "can raise dust levels above allowable limits."
To an animal unaccustomed to eating large amounts of grain, one grain-based meal can be fatal. Grassfed cattle, bison, and sheep remain on their original diet of pasture and hay their entire lives and never have to undergo the stress of adapting to an artificial diet.
ASPCA | American Society for the Prevention of Cruelty …
In the "what will they think of next" category, feedlot nutritionists have been experimenting with substituting kitchen pot scrubbers for hay. Feedlot cattle need some roughage in their diet in addition to the grain concentrate or they will become sick and gain weight more slowly. But why bring in all that bulky hay, reasoned investigators, when pot scrubbers might do the trick? To test this novel idea, the scientists fed a group of steers a high-grain diet and then inserted either zero, four, or eight plastic scrubbers into each animal's rumen (stomach). The experiment appeared to work. "From day 113 to 152, steers provided with pot scrubbers had 16% greater average daily gain than those fed the 100% concentrate diet without pot scrubbers."