At this point in the year, beef producers have eliminated a good portion of those winter haystacks and are hoping green spring grass is in the future. Whether you’re feeding a mixed ration with a feed truck or forking hay off the wagon pulled by a team of horses, those animals need feed every day. However, is the feed being delivered necessarily what those cows need for their stage of production? With the price of feed lately, this is a good thing to consider for any cattle owner.
Cattle have different requirements of energy, protein, minerals and vitamins depending on their age, mature weight, body condition score (BCS) and stage of production cycle. For example, your bred replacement heifer calving out for the first time this year is not only growing a calf but is still growing herself, since she hasn’t reached a mature bodyweight. This heifer’s needs are going to be considerably different than a 6-year-old cow that has already reached her mature size and only needs the nutrition to maintain that size along with taking care of the calf. Of course, these two cows are going to be eating different amounts of feed due to difference in the capacity of the rumen, and the quality of that feed will be different since the heifer will need a higher plane of nutrition to accomplish all that she is being asked to do.
Just what are those differences in the plane of nutrition for these animals? Well, the entire story is more than can fit in this article. Nutritional need charts for cattle have been created by the National Research Council (NRC) and can be found in the book Nutrient Requirements for Beef Cattle. These tables are also available on some extension websites, including Oklahoma State University and University of Arkansas.
During this time of year, when the cows either have calved or are very close to doing so, one must also be aware of how nutritional needs change for a pregnant cow who then calves and begins producing milk for her calf. Let’s go back to our previous analogy to explore this change. That pregnant first-time heifer, weighing about 950 pounds, is going to need 23 pounds of dry matter with 12.4 pounds of that being composed of the total digestible nutrients (TDN; the sum of the digestible fiber, lipids, protein and carbohydrates within a diet). After she calves, those numbers change since she is no longer pregnant and will now be producing milk for that calf. Those new requirements go up to needing about 24 pounds of dry matter, with the TDN increasing to 14.6 pounds (2.2-pound increase). For that heifer to now produce milk and continue to gain weight, this transition will require about a pound more dry matter every day and a 0.74-pound increase in the daily amount of protein needed. To accomplish this, not only must a little more feed be provided each day, but the quality of the feed must also increase to ensure that the required TDN and protein increases are met.
The older cow from our earlier example will also need a ration adjustment, but in different ways. Prior to calving, a 1,200-pound cow will be needing to eat 23.5 pounds of dry matter, with 13.9 pounds being TDN. After calving, that same 1,200-pound cow will need to eat 27.8 pounds of dry matter, of which 15.9 pounds is TDN. This difference involves an increase of 4.3 pounds of dry matter and 1.14 pounds of protein. This older cow is not going to need as much energy or protein (as a percent of the total ration) as the younger heifer will.
You may ask: Are all those changes necessary? Perhaps you have been feeding your entire herd the same type and quantity of feed, regardless of their stage of production, and have gotten along “just fine.” Well, “just fine” might have been OK in the past. However, couldn’t your operation be more successful and efficient with just a little bit more effort? With the increased prices of the supplies, materials and feed needed to run a cattle operation, every live calf and every pound gained are needed more than ever. Previous research has shown that when cattle are given 100% of their nutritional needs, they are able to maintain a proper BCS, have higher rates of live calves born and are better able to maintain a healthy calf.
A study done in Wyoming showed that heifers receiving only 50% of their pre-calving energy requirements for 100 days prior to calving lost 12.7 pounds and had a high percentage of assisted births, even though the calves had a lighter birthweight. The same study also looked at mature cows fed a lower-quality ration before and after calving. They found that when compared to other cows that were fed better, these cows on the lower ration had 10% fewer calves born alive and 29% fewer calves that were alive at weaning time. Those calves that were born alive had lighter birthweights and a higher incidence of scours than calves born to cows who had access to better nutrition.
Nutrition also plays a vital role in getting those animals rebred. One study showed that cows provided a higher-quality ration (set to gain 2 pounds per day) had a shorter time period between calving and first estrus than cows fed a lower-quality ration (set to gain 1 pound per day). Larger dominant follicles during estrus were also noted for cows that were able to meet more of those nutritional needs. All of this contributed to an average pregnancy rate of 76.3% for the cows fed at the high plane of nutrition compared to only an average of 57.6% for the lower plane of nutrition.
A few pieces of information are needed to move you toward succeeding in providing the needed feed to your animals. First, the nutrient requirement tables that were mentioned previously. Secondly, information about the nutritional value of your feedstuffs. That can be as simple as looking at a feed label for feedstuffs in bags, totes or tubs. The feedstuffs in the stackyard are going to require you to get a sample with a hay probe and submit for analysis (unless your hay provider has already done this work prior to your purchase of the forage). This process is not too difficult and can provide valuable data about what you are actually feeding your stock. Talk to your local nutritionist or extension educator for more information about this process. At the very least, you could simply be observant and keep record of the BCS of the cattle. If they seem to be losing BCS, then you need to increase the quantity and/or quality of feed, and vice versa for animals who might be gaining to the point of an excessive BCS.
During these winter feeding months (or the full year), it is probably a good idea to continually think about your cattle and their current needs and if the ration you have built for them is adequately meeting their needs. Local livestock nutritionists and extension educators are great people to talk to and consult with to see if you are on the right track. These conversations can help you to maximize feeding efficiency, help you to not waste feed, prevent your cattle from losing BCS and ensure your cattle can accomplish all you are asking them to do.
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