Cattle may be showing the effect of the drought, not necessarily by poor weight gain and performance, but with mortality by what they are eating. The drought has proven to be detrimental not only to field crops and pasture, but to livestock whose food choices have been compromised, and some of those choices have caused death.
The drought is bringing some unusual problems to the forefront for livestock producers, says Kansas State University veterinarian Larry Hollis. He says weedy plants may have more drought tolerance and will out-compete desirable grasses and begin their proliferation. He also says when the desirable species of grasses have been consumed they have failed to re-grow in the drought and only the weedy species are left in a green state. Hollis says both of these scenarios can become a problem if the weedy plants contain any toxic components. He says when pastures are not properly managed or forage is short, livestock are left with little choice but to consume toxic plants. And he says they will eat toxic plants if starved.
Also at Kansas State, another veterinarian, Gregg Hanzlicek, was asked to solve the death of several calves on a ranch that had suffered from the drought. He said the area had been through 2-3 years of drought conditions, but the herd was well-managed and there was plenty of milk for the calves. Hanzlicek said there was little grass for grazing and the calves were grazing on multiple weeds. One was found to be toxic and cause chronic liver toxicity, with the calves being found to have died from liver toxicity. He said in drought conditions, animals will graze on plants they usually don’t under normal conditions. Hanzlicek recommended the producer move the cattle off the pasture and wean the calves early. And he acknowledged that drought situations sometimes prevent that alternative, but to supplement their feed every other day to keep them full and prevent grazing on plants they normally avoid.
Such feed planning and management is more critical this year than in the past, says Dennis Stein http://www.plantmanagementnetwork.org/pub/fg/news/2012/FeedPlanning/ at Michigan State University. He says with the low hay carryout from 2011 and the severe reduction in available forage in 2012, farms should work to estimate their total feed needs through the remainder of the growing season. He recommends development of a feed inventory, which will account for the feed stored on the farm, multiplied by the density of the various types of stored feed. He recommended a handbook that will determine quantities of feed based on volume measurements. He also referred livestock producers to a feed inventory spreadsheet that will calculation nutrition, but volume measurements will have to be made.