David P. Price is a consulting nutritionist specializing in feedlot and range cattle
Years ago, manure was a valuable commodity. Back in the ’60s and early ’70s manure constituted a cash crop for feedlots.
Then suddenly manure fell out of favour with farmers. Why? Some say it was the advent of chemical/commercial fertilizers. Urea is made from petroleum and when gasoline was 25 cents/ gallon, urea was cheap. It was also easier to deliver. It didn’t contain the bulk of manure.
But the bulk in manure is organic matter, something you can’t buy commercially, but is delivered free with manure. I’m not an agronomist, but I do know organic matter is valuable. Most important of all, it helps hold moisture.
The reality however, is that it was not price or convenience that led to manure falling out of favour as a fertilizer. It was salt; and to a lesser extent calcium.
The feedlot industry first developed in the southwestern U. S., where sorghum was the principal feed grain. For some reason sorghum has a greater tendency to cause urinary calculi (waterbelly) than other grains, and adding excess salt to the ration became standard operating procedure as a means to increase water consumption and function as a prophylaxis for calculi formation.
Commercial feedmills were only too happy to add excess salt to their supplements, since salt is about the cheapest ingredient available. Onequarter to a half per cent salt in the ration began to appear in textbooks, and later, even computer software.
Twenty-five years ago, to my surprise, I found that excess salt was being added to virtually all feedlot rations (including those that do not contain sorghum). I published in the trade press how detrimental this practice is, and that trade journal article became text material in a number of universities.
Yet 18 months ago I discovered that excess salt was still routinely being added to feedlot supplements independent of the feed grain or