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Have you ever seen a university study or heard a feed company tell you NOT to buy that supplement?  The reality is cow/calf producers pour millions of dollars a year into nutrition that is supplementing the wrong thing at the wrong time.  At certain times of the year and during specific phases of the production cycle supplementation is generally needed for cattle to perform at the levels that we demand of them, but it doesn’t have to break the bank, or be complicated.  Before we go throwing dollars away, let’s take a look at what is actually needed to meet the needs of the cow and the calf during the third trimester of pregnancy.

Some basics to start with.  The protein requirement of a cow in third trimester increases by roughly 20% over second trimester.  Protein needs are measured in pounds per day, not a percentage on a feed analysis. For simple numbers let’s say the protein requirement (1,300 lb cow) goes from 1.6 lbs protein daily during second trimester to 2 lbs daily in the third.  Also, total intake needs (dry matter basis) increase from 1.7% of the cow’s body weight in second trimester to 2% in the third trimester. TDN requirements increase from 50% to 54%.  

Why do we care about this?  It’s been proven multiple times in multiple trials over the last 30-40 years that cows in third trimester who lose weight, or go into the third trimester thin (below a body condition score of 5)  will have a host of issues ranging from increased calving difficulty, weaker calves, sicklier calves, poor breed back and in some cases abortion. To avoid these issues many have fallen prey to the fear factor and give their cattle a diet that far exceeds the cows nutrition requirement.  This results is wasted money and creates high-input cattle that require more feed and supplements to produce at the same level as more genetically efficient cattle. By throwing excess nutrition at the cow we don’t put enough genetic pressure on the herd to cull poor performers. When we put the true need into perspective it looks like this…A 1300 lb cow should be able to sustain her body condition in the second trimester with 22 lbs of 7.1% CP hay, and in third trimester with 25 lbs of a 7.9% CP hay.  Mixing alfalfa with barley straw will in most cases get you to the same end. Testing feed will result in optimizing feed and supplement expenditures. Working with a nutritionist to test feeds and formulate a cost effective ration is one of the best money saving actions you can take. Money you don’t spend is tax free and is already in the bank. Don’t blow money where you don’t have to, but don’t short change the cow either.

Those who calve in the winter from January to March may already be entering the third trimester now.  Winter calving allows for far less lee way in “bending the rules” for third trimester nutrition. While the proven nutrition research does in fact indicate that we need to keep the cows body condition up during third trimester, spring time calvers can push the edge of the envelope a little more as calving in April thru June puts the cow in a position to be on the gain during calving and breeding due to better feed in spring and early summer.  The spring calving cow may be able to loose some weight during the winter and still rebreed. Winter calving cows can rarely do this cost effectively as most producers are feeding winter calving cows and increases in body condition with fed hay are rarely successful nor cost effective. While it may be possible to short the spring calving cow a little and pick it up again on the back end, research also indicates, the calf may still struggle with health and growth issues throughout its life due to the decreased nutrition it received in utero.  Bottom line is, the cow may be fine, but the calf production will most likely suffer if the cow falls in body condition.

Generally speaking protein is the limiting macro nutrient during winter and third trimester.  If after testing feeds (including fall and winter pasture if applicable), it is determined that supplementation is needed, use the cheapest source of protein possible.  Often in Montana that will be alfalfa hay fed twice a week. Protein doesn’t have to be fed daily as long as it is provided often enough to stimulate the rumen microbes to keep digesting lower quality forages.  If cattle are too far from home and a once a week supplement is used such as a liquid or lick tub/block, buy supplements based on the cheapest price per pound of protein, not how cheap it is per ton. A 20% CP supplement may be $50 per ton cheaper, but the cost per pound of protein for a higher percentage of protein is usually the most cost effective.  If the protein source runs out even as fast as day 3 or 4 on a one-week ration, the rumen will still be stimulated to keep the cow going until the next supplementation day. Generally speaking it takes 4-5 days to make major changes in the rumen microbe population while on range, so if they have protein in front of them for 3-4 days of the week and go without for 3-4 days they still meet the need.

Pasture management can also keep the protein levels up.  If cattle are left to pick over a large area of forage, they will cherry pick the best feed first and then marginal feed last.  This may lead the nutrition level of a pasture to be adequate in the first week, but in subsequent weeks the nutrition level declines as the better feed gets consumed.  With tighter grouping and more frequent moves, the overall nutritional plain will be kept as high as possible as the cattle are forced to consume all the forage uniformly, thus consuming the lower quality along with the better forages.  This can decrease the need for protein supplementation resulting in saved money and better range conditions on a year to year basis.

Mineral nutrition during third trimester needs to be considered as well.  Cattle maintain stores of trace minerals in the liver and the calf will benefit from that once born.  Trace minerals don’t pass through the milk well, so calves are very reliant on the mineral stores they are born with until they begin consuming minerals on their own.  Often mineral starved cows give birth to calves that do very well until a month old and their health begins to decline as they run out of the mineral stores they were born with.  The cost of a mineral program is generally around $25-$30 per head per year and the benefits touch many areas of production to include cow and calf immunity, reproduction, growth and intake.

Finally, do not try to use nutrition to overcome bad genetics.  If you find yourself saying things like “our cows just seem to need a little extra,” or “our performance falls off if we don’t go above and beyond,” you may want to consider reevaluating your genetic program.  Supplementation and nutrition management is intended to ensure we meet the cows need so they can work for us, not to continue buying more inputs to keep the cows in the herd. Do your part to provide the cow’s needs but make her do her part to meet yours as well.

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