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Total-Mixed-Ration & Individuality in Feeding Animals

By Hugh J. Karreman, V.M.D.

As I look at the calendar on my wall, I see a picture of a boy walking in front of a long line of about a hundred cows eating a total mixed ration (TMR) at a feed bunk. While it can be easy to simply see the long line of cows as identical to each other in terms of a production unit, it is just as easy to see each and every animal as unique and individual from each other. Seeing the individuality of animals allows us to think beyond the simplistic view of group averages to realizing that each animal has specific nutritional needs.

This concept is true whether we are looking at a herd of cows, a herd of goats or pigs, a flock of sheep, a band of horses, a pride of lions, or even a school of fish. Each animal will respond differently to the feed it is fed or finds because of different individual metabolic needs. Metabolic needs will differ upon each animal’s genetic make-up as well as the stage of life.

A TMR is designed to perfectly feed only the perfectly av­erage cow in the herd. While TMRs can provide a herd with a desirable forage-to-grain ratio, the minerals delivered will not be accurate to the needs for most cows. It isn’t rocket science to realize that there is a quite a range of animals in a herd, varying in body size to different stages of lactation and preg­nancy and growth. So if you have a herd of eighty cows with sixty-five Holsteins and fifteen Jerseys, it is rather obvious that each of their needs will be different. Add to this that some of each will be early lactation and climbing in milk production while others are past peak and some will have been recently bred while others are long bred, and it becomes very obvious that their mineral needs will vary greatly, yet the TMR deliv­ers the same exact homogeneous mix of food and minerals to them all.

cattle feeding
Considering each animal’s individual dietary needs is not easy, but knowing every animal has a different metabolism is important.

Some animals may need relatively more of one mineral than another. This would hold true for any mineral element. For instance, fresh cows need lots more daily calcium than cows ready to dry off. Calcium is tightly regulated in the blood­stream via the parathyroid gland, and we know that Jerseys have more problems keeping calcium in balance than other breeds. Zinc, needed for good hoof health, may be needed in different amounts for Holsteins with their white hooves than for Brown Swiss with their black hooves. Each animal will need different proportions of minerals in her diet than the next animal, yet the TMR delivers the same proportion day after day after day.


What am I trying to get at? Well, it seems to me that re­gardless of how smart (or not) you may consider cows, sim­ply realizing that individuals will need and uniquely respond to what is in front of them makes sense. And, additionally, it has been proven that cows can select what they need by vari­ous internal bio-feedback mechanisms. It is well known that foraging animals will seek out what they need, sometimes in depraved ways: cows eating rabbits to get phosphorus they desperately crave, animals eating dirt to take in minerals that are lacking in the diet fed out to them, pre-weaned calves eat­ing their bedding to get fiber because they are being denied hay until weaning, etc. It is also known that animals will select plant species that would seem to play no real part of their diet: calves eating burdock leaves, horses eating willow leaves, monkeys eating bitter, tannin-containing leaves, etc. In these cases they are self-medicating. How they sense what to eat is still a big mystery, but it is clear that they are drawn to certain things to satisfy deep urges. Call it intuition, call it instinct, call it whatever you will, but they are trying to tell us some­thing: as individuals they can and do select what they want in their diet.

Therefore, maybe we should provide only the basics of the ration in a TMR so that the baseline of the animals is covered, but then rely more heavily on them to self-select what else they need, especially in terms of minerals. In practical terms, this would mean providing sources of free-choice minerals such as kelp, bioavailable sources of calcium, phosphorus, magnesium, zinc, bicarb, clay, and trace mineralized salt. Be prepared to watch some of the minerals disappear quickly. Be happy, for you have then allowed your animals to balance their own ration — and to tell you what your base ration may be lacking.

This same concept holds for pasture: try to have a biodiverse pasture. Having only one or two plant species (like white clover and perennial rye grass) in a pasture will not lead to a very balanced intake, whereas a pasture full of variety (and yes, “weeds”) will allow animals to pick and choose to their heart’s content. If you’re worried about “weeds” being refused, please know that animals eating “weeds” should tell you something, for the “weeds” usually have quite a good mineral profile as many are somewhat deeply rooted or at least provide variety to the one or two plant species purposely planted for pasture intake. The only time I can see a monoculture being grown would be with a warm season annual like sorghum-sudan to germinate quickly and give vigorous growth during the heat when the native cool season plants aren’t growing.

Providing diversity, both in plants and minerals, in the diet is a good thing, for it parallels both the diversity of individuals in a herd as well as allowing them to choose what they spe­cifically want to eat. Diversity is the opposite of homogeniza­tion. Too many things in life seem to be “homogenized” these days. Isn’t it ironic that individuality is both highly prized in our general society but also made bland by everyone buying the same stuff at the same chain stores? Being unique is certainly good, right? Likewise, each animal is unique, an individual with individual needs— whether it is one of a line of a hundred cows at a feed bunk or individually named animals in a small, tie-stall herd. Each and every one of them has individual needs that can best be met by careful attention to correct feeding. Allowing animals themselves to select pasture plants and freely choose various minerals provided allow them to satisfy their own unique set of dietary needs.

Source: Four-Seasons Cattle Care