Mineral Balance for the Breeding HerdFri, 09 Apr 2021 09:00:20 CDT
Grazing cattle will benefit from a mineral supplementation program. The challenge is figuring out what they are getting from the forage base, what they need, and how best to deliver a supplement product that fills the gaps to meet their needs, but doesn’t create problems (often unseen and unkown) by delivering too much of something. The challenge is that “what they are getting” and “what they need” are constantly changing throughout the year. Forage mineral composition varys by soil type, forage species and maturity, current growing conditions, fertilization history, grazing management and so on. Then a beef cow’s requirements for minerals fluctuate with the stages of production. Everything is a moving target. It’s a little like trying to figure out if the fish scale reads 93 vs 94 lb while new baby’s momma is doing a great job convincing you that she is not bluffing. Mineral nutrition is not that exciting although perhaps similar in the sense that calf birth weight records, even if not perfect every time, have proven to be a powerful source of information over the years.
A great tool to evaluate the mineral program is to conduct one or multiple mineral balance exercises. Especially early on in this process, producers should consider engaging their Extension Educator, veterinarian or a feed industry expert to assist or advise. A mineral balance excercise involves developing a simple, consistent record keeping system to track critical pieces of information; forage mineral composition during that time of year and your cow herds’ average or “normal” mineral consumption pattern during that same time of year. Mineral balance excercises could be conducted as few times as once during the grazing season and once for the winter feeding period, or they can be completed on a quarterly or even a monthly basis. Several commercial nutrition companies provide services to conduct these balance excercises and follow up by recommending or manufacturing mineral formulations customized to your operation’s needs. You can find a handy phone app to track mineral consumption at: <http://beef.okstate.edu/pages/calculators>.
Most commercial livestock nutrition laboratories provide forage mineral composition analytical services for a reasonable fee. For example, our lab here at OSU charges $12 per sample to get macro and micro minerals. One might get started by simply sampling and testing harvested hay or silage each year and developing a spreadsheet where you can easily access and summarize those records over time. A more ambitious approach might be to collect “hand-plucked” samples from one or more pastures each month. The idea of the hand-plucking method is to select only plants and parts of plants that you believe to represent what your cattle are currently grazing.
The OSU Cowculator nutrition evaluation program (<http://beef.okstate.edu/pages/calculators>) is a great tool to simplify a mineral balance exercise. The feed library allows one to enter their own forage nutritive values and mineral supplement products/formulations. The “Balance” page provides guidance to estimate daily forage consumption and then a place to input the amount of mineral the cows are expected to consume. From there, a table is provided showing you the difference between “what they are getting” and “what they need”.
As an example, the figure shows the nutritive balance table for 1,200 pound lactating beef cows grazing lush spring tallgrass prairie forage and consuming 3.3 ounces per day of a commercial mineral supplement. You can quickly view the status incidators in the right column to determine where major gaps or excesses exist. In this examle, these cows are projected to be about 7 grams per day short of sodium. Since salt contains 40% sodium, this suggests that these cows could use an additional 15 grams of salt or about 0.5 ounce per day. There are several excesses identified in this example. Most mineral balance excercises in Oklahoma are going to reveal excessive potassium and excessive iron due to high forage concentration of both minerals. The other revelation in this balance exercise the the considerable excess of selenium. Thus, the conclusion of this exercise is that a) this mineral supplement is a good complement to this forage source for this time of year and b) one could blend about 10 to 15% salt with the mineral to better match the sodium requirement with intake and c) the selenium concentration in the commercial product could be reduced by about 50% if that were an option. It most definitely points out that there is no need to purchase mineral product containing a greater concentration of selenium.
Consider collecting forage mineral composition data and mineral supplement consumption data several years in a row to see the variation (or maybe the consistency) of those patterns over time. Finally, use that valuable information to conduct mineral balance exercises for the different seasons. This should lead to you having confidence that your cattle are getting what they need when they need it and potentially to cost savings.
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