Animal Health Matters: Thriftiness is not the same as ingenuity
One of the most enduring qualities of farmers and ranchers is their resourcefulness. I can’t count the number of times I’ve been to a client’s farm only to notice some new contraption they’ve come up with to solve a specific everyday problem – opening gates without leaving the 4-wheeler or lifting up a down cow, for example.
I particularly remember a “rig” one of my older beef clients proudly showed off to me one day after a call. Needing to check on the silage in his stave silo, but no longer able to climb the ladder, he devised a winch with a seat attached, operated by a handheld switch to lift him up to the top.
Those ingrained traits of rejiggering and repurposing lead producers, when presented with a problem, to first look around the farm for an existing item they could use in another way. Why buy something new when we can make something work that we already have? I very much admire and subscribe to that line of thinking, but I can think of one big exception.
Not infrequently, cattle producers find themselves in need of hauling water to cattle. Perhaps the existing water source has gone bad due to drought or blue green algae, or they’ve had to move cattle somewhere with no water options. Producers who do this regularly have dedicated tanks and trucks to accomplish this task.
But others, who only occasionally haul water to cattle, are often tempted to look around the farm to see what they could use just this once or twice. Sometimes the potential solution pops up in the form of that big polyethylene tank they used to haul fertilizer out to the fields in the spring.
Every year I get at least one report from a veterinarian about clients who lost cattle soon after hauling them water. In these cases, the problem wasn’t the water they put into the tank, it was the tank itself – or more accurately, what was previously in the tank.
The common diagnosis for the cause of death in these cattle is that of nitrate poisoning. I’ve previously written about nitrate poisoning in cattle. These compounds, when processed by the animal’s rumen microbes, form nitrite molecules which bind to red blood cells. This makes them unable to carry oxygen to the body’s cells and the animal essentially suffocates from within.
Animals that consume higher concentrations of nitrates often are simply found dead. If people are around to observe poisoned cattle, they might notice anxiousness, fast and difficult breathing, incoordination and collapse. Non-fatal nitrate levels can be problematic too, especially for pregnant cows, who may go on to abort their pregnancy even if they don’t show the other signs of poisoning.
Usually cattle encounter high levels of nitrates in feed, when the forage is stressed due to drought or other environmentally harsh conditions. But in these water-related cases, the nitrates come from the residue of nitrogen-containing fertilizer in the plastic tank walls leaching into the water. If the vessel has been used to carry urea, that’s another potential toxin for cattle, although oftentimes urea is hauled to the fields in granular, not liquid form. Urea toxicity has a different mechanism in poisoned cattle (excessive ammonia production in the system), but is no less problematic.
Of course, most producers instinctively realize that tanks like this should be cleaned out prior to their use as water carriers and do so. Unfortunately, that doesn’t work. Not even the most vigorous power washing or scrubbing can remove the chemicals, which have bound to the plastic fibers of the tank wall. Even the cleanest-looking or -smelling tank can leach out enough nitrogen into the water to cause problems for cattle.
The solution, therefore, involves less ingenuity and more expense. Purchasing a tank that’s dedicated only for water hauling is the answer. (Borrowing one from a trusted neighbor is always another option). Most of the case reports I get from veterinarians who have witnessed death losses from these situations involve multiple animals. In all of these cases, the cost of the lost cattle far outweighs the expense of the tank.
I’m all for producers repurposing whatever they can. But in some cases, as with using fertilizer tanks to haul cattle water, that thriftiness can be very counter-productive.
Russ Daly, DVM, is the Extension Veterinarian at South Dakota State University. He can be reached via e-mail at email@example.com or at 605-688-5171.