Using salt to limit supplement intake on pasture continues to be a powerful way to provide free-choice access with less of the delivery costs associated with hand-feeding. But it does require ongoing effort.

“Use of a self-feeding supplementation program doesn’t mean put it out and forget it,” explains Dale Blasi, Kansas State University Extension beef stocker specialist. “For example, one can expect to modify the salt content in a self-feeding supplement an average of five times over the course of a grazing season to make sure supplement consumption is consistent with intended intake levels.”

Among the considerations producers need to keep in mind when using salt as the limiter, Blasi says:
 

• “The proportion of salt in the self-fed mixture may vary from 5% to 45%. To determine the amount of salt needed in a supplement, you need to know the desired level of supplement intake and weight of cattle being supplemented… The amount of salt to include in the mixture depends upon the intake of the supplement desired. Salt used in self-feeding supplements should be plain white salt.”

• “To increase supplement intake, decrease salt content; to decrease intake, increase the salt. Table 1 estimates the range in salt intake for calves of various weights after an adjustment phase of 2-3 weeks when cattle are adapting to the salt and nutrient content of forage.”
 

 
Table 1. Estimated range of salt intake of cattle fed salt-limited supplements
Body
weight
Salt consumption lbs./day
(lbs.) Low Avg. High
300 0.3 0.5 0.6
500 0.5 0.6 0.7
700 0.6 0.7 0.9
900 0.7 0.9 1.1
1100 0.8 1.1 1.3


• “Factors other than desired intake and cattle weight can also affect the concentration of salt required. Age can affect salt intake because older animals require more salt to obtain the same level of restriction compared with equal weight younger animals. As quality and quantity of the standing grass declines, more salt will be required. As animals become accustomed to the supplement, it may be necessary to increase the proportion of salt. Level of forage intake, palatability of supplement ingredients and salt content of the water are additional factors that may require adjustments in salt levels.”

• “When cattle are accustomed to eating supplements but unfamiliar with self-fed supplements, overeating can be prevented by starting with a higher salt level than intended for a period of 7-10 days. For younger cattle unacquainted with concentrates, it’s particularly important to ensure against overeating. Thus, it’s advised to initially hand-feed the supplement with no salt for a couple of days to confirm all calves are familiar with the supplement. The next step would be hand-feeding the supplement with salt included for a couple of days before a total transition to full feeding. Never introduce self-feeding supplements in situations where animals are hungry.”

• “Free-choice supplements containing salt are most effective when presented to cattle in a meal package. To prevent separation from occurring, the particle sizes of the basal supplement and salt should be similar. Coarsely ground salt is more effective than finely ground salt. If grain is included, it should be cracked or coarsely ground as well. While pelleting helps minimize separation, it’s not recommended because of added cost. Minerals typically provided for calves on grass can be included in the total supplement as well.”

• “For a daily supplement intake of 1 lbs. or more, ionophores such as Rumensin or Bovatec can be included at approved levels for increased rate of weight gain. Producers can expect a 25%-40% decline in the level of salt needed to limit intake when Rumensin is included. Furthermore, adding Rumensin to self-feeding supplements will reduce the number of adjustments in salt concentration required to maintain the desired intake.”

• “To prevent potential toxicities resulting from excessive salt intake, a clean, plentiful and dependable water supply is a necessity. Water requirements can easily increase 50%-100% when using this system. Producers using a salt-limited supplement are encouraged to submit a representative water sample to a commercial laboratory to determine the total dissolved solids (TDS) content. Caution is necessary in using salt-limited supplements when water contains above 5,000 ppm TDS.”

• “Self-feeders should be portable and able to protect the mixture from wind and rain. As a rule of thumb, 20% of animals in a pasture should be able to eat from a feeder at any one time. Strategic placement of the portable self-feeders will facilitate and direct grazing distribution towards areas of the pasture that have had low grazing pressure. Avoid placement of the feeders adjacent to water sources as grazing distribution will be limited.”

• “In order to properly monitor supplement consumption, it’s important to know the initial volume and weight of the salt mixture placed in the feeder. By knowing this information beforehand, and marking the level of feed in the feeder every few days, one can approximate the amount being consumed per head per day. With careful monitoring, salt can be effectively used to limit intake on self-fed pasture supplements.”
For more details, see Blasi’s insightful explanation in the May 2010 K-State Beef Tips newsletter.
www.asi.ksu.edu/beeftips