Cattlemen continue to investigate ways to reduce cow costs. One management tool frequently used is regulating feed intake with salt. Research would suggest that regulating feed intake with salt is not precise meaning that the salt content may need to be adjusted throughout the feeding period to achieve the desired feed intake. As a management practice, self-feeding supplements tend to allow timid, slow-eating cows to get their share and it is an easy method of providing Vitamin A, phosphorus and other feed additives.
Salt should always be supplemented to beef cows. Salt is made up of Sodium and Chloride (NaCl) and these elements are used in a number of important reactions in the body. Daily salt requirement for mature cattle is less than 1 oz/head/day. Voluntary salt intake often exceeds minimum needs. Because there are practical limits to the amount of salt cattle eat, salt can be used to restrict the consumption of highly palatable feeds. In such instances daily voluntary intake of salt will approximate 0.1 pound salt/100 pounds body weight for most classes of cattle.
Total salt intake is the amount in the feeds that are eaten and the amount in the water that is drank. Salt toxicity is seldom seen in cattle because of their high tolerance for salt. As a rule-of-thumb, cattle on salt mixtures drink 50 or 75 percent more water than normal or approximately 5 gallons of additional water for each pound of salt. If only salty water is available, cattle will often refuse the supplement or may be forced into a toxicity situation. Salt content of water is usually measured by total dissolved solids (TDS) which includes calcium, magnesium, sodium chlorides, sulfates and bicarbonates. Caution is necessary in using salt-limited supplements when water contains above 5,000 ppm TDS. This analysis can usually be obtained through the analytical laboratories.
When cattle are accustomed to eating supplements but are unaccustomed to self-feeding, overeating can be prevented by starting with a high salt level (50:50 or even 60:40 salt to meal) and then reducing salt level to obtain desired level of intake. If cattle have not eaten concentrates before, a training period of a week or more of daily hand feeding of meal without added salt may be necessary, particularly with young cattle. Usually is necessary to increase the salt content of the mix over a period of time as cattle become accustomed to the high salt level. Self feeders should protect the feed/salt mixtures from wind and rain and be portable.