The nutritional value of forage changes throughout the growing season and changes in crude protein and digestibility are often discussed. However, other nutrients also change in forage throughout the growing season such as vitamin A. Vitamin A is a dietary essential nutrient, meaning that the animal cannot synthesize it, important for vision, immune function, and reproduction. The estimated vitamin A requirement for gestating cows, lactating cows, and growing calves is 1,270, 1,770, and 1,000 IU/lb dry feed or 27, 38, and 21 IU/lb body weight. Thus, a 1300-lb spring calving cow would need to consume 50,000 IU from March to October and 35,000 from October to March.
The vitamin A content of forages is not equal across species or locations. Figure 1 illustrates the vitamin A content of forages in Ohio and North Carolina. Fescue pasture easily meets the nutritional requirements of gestating and lactating cows, but alfalfa, fescue, and orchardgrass hay may be marginal to deficient. Additionally, growing native prairie grasses exceed the Vitamin A requirement of beef cows, but dormant forages are deficient (Figure 2). Thus, vitamin A supplementation is probably not necessary during the grazing season to meet the current nutritional requirements, but dry conditions can significantly decrease vitamin A in grazed forage.
Beef cows can store vitamin A in their liver for 4 to 6 months and so may be able to go through the fall with minimal supplementation. We have little information on the amount of vitamin A necessary to build up liver stores and, thus, summer mineral supplements often contain enough vitamin A to meet the current requirements. There is little chance of toxicity problems with over feeding vitamin A.
Vitamin A needs to be supplemented from late fall through early spring until cows are grazing green pastures. A vitamin and mineral supplement with a target intake of 4 oz/head/day should contain 150,000 to 200,000 IU/lb of vitamin A.
Changing vitamin A content of forages throughout the year, the species of forage, and the storage method and time is important to consider when evaluating vitamin and mineral supplements. Work with your veterinarian or nutritionist to make sure the supplementation program is adequate, but not overly costly.
The push for renewable energy has a full head of steam and is and will cause changes in how we feed cattle. Many remember the ethanol boom in the 2000s that resulted in a run up in corn prices and a large supply of corn ethanol coproducts (distillers grains, corn steep, etc.). The beef industry adapted by replacing corn in feedlot rations and using distillers grains in supplements for cows and calves grazing pasture.
During the ethanol process, corn starch is fermented to ethanol resulting in the distillers grains consisting of the corn hull, protein, and fat making it an excellent feed source for cattle. The hull is a highly digestible fiber that works well in supplements for cattle consuming high forage diets as it does not decrease rumen pH like starch and consequently decrease forage digestion. If dried correctly, the protein in distillers grains provides a good balance of rumen degradable and undegradable protein, and the fat increases the energy value without negatively affecting forage digestion as it is not free oil.
The new wave of renewable energy is focused on biodiesel, which at this point is primarily coming from production of oilseed crops – soybeans, canola, cottonseed, etc. Thus, we expect to see a shift in acres of oilseed crops replacing acres of corn. Reduced production of corn will again increase the price of corn as ethanol and livestock vie for the lower supply. However, the increased crush of oilseeds will result in a larger supply of coproducts from these manufacturing processes. The supply of oilseed meals – soybean meal, cottonseed meal, and canola meal – will increase making them more cost effective for cattle diets and supplements. Additionally, soybean hulls are a high fiber coproduct of the soybean crushing process.
Potential nutritional deficiencies exist with replacing distillers grains with oilseed meal and soybean hulls in beef cattle diets. Soybean hulls are a highly digestible fiber like distillers grains, but lack protein and fat; thus, have a lower energy value than distillers grains (Figure 1). Oilseed meals are high in protein (soybean meal = 54%; cottonseed meal = 45%; canola meal = 41%), but obviously low in fat. Thus, coproducts of the oilseed crushing process lack some nutritional aspects of distillers grains.
A recent study evaluated replacing distillers grains in a feedlot finishing ration with a combination of soybean meal and soybean hulls. In this study, there was no difference in cattle performance or carcass quality between treatments. Thus, a combination of soybean meal and hulls was able to adequately replace distillers grains at 15% of a dry rolled corn diet. Further research is needed to evaluate these types of scenarios in various diets and production systems.
In conclusion, feed ingredient availability is changing, which will affect diet formulations for drylot cattle and supplements for pasture cattle. The availability of distillers grains may decrease and ethanol manufacturing may look to remove the fat and protein from distillers grains for more valuable markets in order to offset the increased cost of corn. However, the availability of coproducts from oilseed manufacturing will increase and can, at least partially, replace the nutrients in distillers grains.
Feeding cows through the winter after a drought season is always challenging, and mineral nutrition is no different. Feeding alternative forages means feeding something different than what you are used to feeding, which means alternative supplementation strategies. Forages differ in their mineral content with legumes typically having greater amounts of calcium than grasses (Table 1). Additionally, some forages have lower content of microminerals as can be seen for copper content of fescue and native prairie hay.
The mineral content of forages is affected by several factors with soil fertility being a primary factor. Mineral content of the forage can only be as good as the mineral content of the soil and the physical and chemical properties of the soil that allow the plant to absorb the mineral into roots. Soil pH is an important chemical property affecting mineral availability to the plant where acidic soils can negatively affect absorption of calcium, phosphorus, and magnesium. However, alkaline soils negatively affect absorption of manganese, copper, and zinc. The proportions of sand, silt, and clay physically affects mineral absorption where minerals can be tightly bound to clay particles reducing the availability to plants, and high sand content reduces water holding capacity thereby reducing the availability to plants.
With drought over much of the country last summer, the mineral content of forages, even if the same hay fields that are always used, is likely different than normal. In legume-grass mixtures, the legumes are generally more drought tolerant than grasses and so the relative production of forage is likely more legume during drought years. Additionally, the drier soil reduces availability of minerals for absorption by the plant, especially phosphorus. Phosphorus in the form of phosphate needs to be solubilized before absorption by plant roots. Thus, phosphorus is an important mineral that may be low in drought-stressed forages.
As spring calving season gets underway, calcium and phosphorus requirements of lactating cows is greater than dry, gestating cows (Figure 1), and depends upon the amount of milk production. Higher milking cows require more calcium and phosphorus. A 1200-lb cow producing 10 lb of milk at peak lactation requires a diet with 0.25 and 0.17% calcium and phosphorus in the diet in early lactation, whereas a cow producing 20 lb of milk at peak lactation requires 0.31 and 0.21% calcium and phosphorus in the diet.
Feeding drought-stressed forages could result in mineral imbalances unless mineral supplementation is adjusted. With increasing mineral requirements, especially for calcium and phosphorus, as cows begin to calve, the likelihood of mineral imbalances increases and could cause some health and reproductive problems. Evaluating the mineral content of your forage resources and mineral supplementation plan is an important step in a drought year.
After calving, milk production of cows increases rapidly to maximum production at approximately 60 days after calving, and then starts to decline. During this time, the growing calf can meet all its nutrient requirements from milk, although it generally begins to consume very small amounts of forage, but as milk production begins to decline the calf must consume more forage to meet nutritional needs. At approximately 90 to 120 days after calving, forage provides most of the calf’s nutrient requirements, which introduces a management decision: should I creep feed?
The decision to creep feed depends on several factors: feed conversion, formulation of creep feed, and price of cattle relative to price of feed. Creep feeding will generally add weight to nursing calves, but the feed conversion can be very poor. The correct way to compute feed conversion of creep feeding is to divide the amount of feed consumed by the added weight to calves above what would be expected without creep feeding. The calf will generally replace forage with creep feed in their diet, and so there is a substitution of forage consumed by non-creep-fed calves. The substitution results in less than 100% of the creep feed consumed increasing nutrient intake by the calf. Thus, feed conversions can range from 8:1 to 15:1 pounds of feed for each additional pound of weight.
Obviously, improving feed conversion would increase the profit potential of creep feeding. The feedstuffs used in the creep feed make little difference in feed conversion most of the time because cereal grains and high-energy coproducts have relatively similar energy densities. However, the type of forage being consumed can make a difference in the response to creep feeds with large amounts of cereal grains/starch such as when creep feeding fall-born calves, because fall-born calves are consuming lower quality dormant or harvested forage through winter months such that starch has a greater negative impact on forage digestion then when creep feeding spring-born calves grazing tall fescue or smooth bromegrass. In situations with lower quality forages, high-fiber coproducts should be the primary energy source and starchy grains should be limited.
Another primary factor affecting feed conversion is the relative difference between energy density and digestibility of the creep feed versus the forage. In situations where the energy density of creep feed is only marginally greater than the grazed forage, then creep feed conversion will be high. However, the greater the difference in digestibility between forage and creep feed, such as with fall-born calves consuming dormant pastures or harvest hay, the better the feed conversion. Additionally, proper formulation of a creep feed to meet the limiting nutrient in the calf’s diet by complementing the forage such as providing limited amounts of rumen degradable and undegradable protein to meet rumen and calf protein requirements can improve feed conversion. When calves are consuming lower quality forages such as dormant pasture or hay, rumen degradable protein may be limiting the ability of rumen microbes to digest the forage. Young calves whose body weight gain is primarily muscle, have high amino acid requirements and thus providing a creep feed high in rumen undegradable protein can assist in meeting the amino acid requirements. Using a method to limit creep feed intake can also improve feed conversion.
The cost of feed and the price of cattle are also major determinants of creep feed profitability. The cost of feed, along with feed conversion, affects the cost of added weight gain. The cost of adding 1 pound of weight needs to be less than the price per pound of weaned calves. The cost per pound of feed multiplied by the expected feed conversion (pounds of feed per pound of added weight) should be less than the price per pound of calves for creep feeding to be profitable.
There are advantages with creep feeding fall-born calves in that feed conversion can be better than for spring-born calves as the relative difference in energy density between creep feed and forage is greater, especially this year when forages with lesser digestibility than usual may be fed. Additionally, fall-born calves are generally sold at a time when weaned calf prices are higher. However, one disadvantage to creep feeding fall-born calves is that feed costs are generally greater in the winter than the summer. But, as cattle country was gripped by drought last summer and continues to be, the cost of creep feed should also be weighed against the cost and availability of hay to carry the cow herd through the winter. Calves will consume 8 to 10 lb of forage between 6 and 8 months of age, which could be the difference between finishing this winter with enough hay to feed the breeding females.
Feed costs typically represent the single largest cost for beef cow-calf producers. Based on Kansas Farm Management Association (KFMA) data for the beef cow-calf enterprise, feed costs (pasture and non-pasture) were 47.0% of total costs in 2021 and 46.4% of total costs for the 2017-2021 average. Thus, it is important that producers know what their feed costs are and how they compare to benchmark values for other producers such that they can manage this important cost for long-term business profitability. While the nutritional requirements of a beef cow are well determined given her genetics, body size, and the environment she is in, the specific feedstuffs used to meet those requirements can vary considerably. There is a trade-off between the use of pasture and non-pasture costs in meeting the nutrient requirements of the cow and her calf. Thus, a producer with higher (lower)-than-average pasture costs might still be competitive with other producers if non-pasture feed costs are lower (higher) than average.
Reported KFMA feed costs are disaggregated into two categories – “pasture” and “feed”, where “feed” basically represents all “non-pasture” feed costs (i.e., hay, supplements, grain, etc.). While breaking total feed costs into pasture and non-pasture categories is still not sufficient to answer all questions about why some producers are more profitable than others, it does help understand some of the differences between producers.
To address some of these cost differences between producers, cow-calf enterprise total feed costs data included in the 2017-2021 KFMA beef cow-calf enterprise analysis were used. Multi-year averages were calculated for total feed costs for each of the 82 operations that had a minimum of three years of data. Figure 1 shows the multi-year average pasture and non-pasture feed costs plotted against each other. There are several points that can be made from this figure. First, the black line represents combinations of pasture and non-pasture feed costs that are equal to the average of total feed cost (i.e., $537 per cow). Values to the right of the black line (52% of the points) represent producers that have total feed costs that are above average. Likewise, values to the left of the line (48% of points) represent producers that have total feed costs that are below average. Second, the two dashed lines represent the average pasture costs of $170 per cow (horizontal dashed line) and average non-pasture costs of $336 per cow (vertical dashed line).
Values in the upper right quadrant (18% of points) represent producers with both pasture and non-pasture feed costs that are above average, which likely will make it difficult for them to be competitive in the long run. Points in the upper left quadrant (29% of points) reflect producers that have above average pasture costs, but below average non-pasture costs. Thus, these producers might be using a longer grazing season and relying less on harvested feedstuffs. The lower right quadrant (30% of points) reflects the opposite scenario where producers have higher non-pasture costs than average, but lower pasture costs (i.e., somebody with a shorter grazing season and relying upon more harvested forages). The points in these two quadrants (i.e., upper left and lower right) reflect producers that are trading off one type of feedstuff for another. Finally, points in the lower left quadrant reflect producers that likely have a competitive advantage as they have both pasture and non-pasture feed costs that are below average (i.e., 22% of operations).
Being in the lower left quadrant might be something to strive for; however, a word of caution needs to be added about what this might represent. Given that a beef cow requires a certain amount of nutrients, having costs below average for both of these suggests one of two things – either the cow is not receiving adequate nutrition, or the feed is valued at below average price/cost. The first statement may be true in any given year, but cannot happen consistently over time as production would suffer and cows might not rebreed. Likely, pasture and/or non-pasture feed costs are valued significantly below average for producers in this quadrant. Producers should always strive to have a competitive advantage, but it is also important to recognize what might be the driving force behind this and whether it is sustainable.
With dry conditions across much of the western United States, grazing regrowth on irrigated alfalfa fields is likely in fall grazing plans for many producers. Alfalfa is a fairly drought tolerant crop and will produce forage in dry conditions. However, alfalfa has several challenges to grazing from animal and plant health perspective.
With its high soluble protein content, alfalfa can easily cause bloat in cattle so cattle should be monitored closely, especially the first few days of grazing. One of the keys to reducing bloat when grazing alfalfa is to not create situations that would cause large swings in forage intake. Any situation that would cause cattle to become overly hungry before or while grazing alfalfa can be problematic.
One method to mitigate the incidence of bloat is to adapt cattle to the alfalfa slowly. First move cattle to the alfalfa field after the morning grazing bout on grass pasture, this way the rumen is full and cattle will not consume large amounts of alfalfa right away. Another method is to only allow cattle access to the alfalfa field for a few hours each day for the first few days so that cattle are consuming other grass forage. However, monitor cattle as some may learn after a few days that they will get access to the alfalfa and wait to eat until then. A third method to mitigate bloat is the use of a feed additive called poloxalene. The compound acts as a surfactant in the rumen to inhibit frothy bloat and can be delivered in a feed supplement or mineral mix. A combination of these methods will likely provide the best bloat prevention.
Grazing alfalfa after a light freeze, especially followed by warm days, can increase bloat problems because freezing ruptures plant cells releasing more soluble proteins. Cattle should be monitored closely when temperatures approach freezing and possibly removed from alfalfa until night time temperatures return to normal.
Alfalfa can also contain high levels of phytoestrogens that can negatively impact reproductive performance of females. Fall-calving cows or fall breeding heifers could be negatively impacted by grazing alfalfa in the fall. However, research studies indicate that phytoestrogen levels generally only reach problematic levels with fungal infection of the alfalfa plant. Water stress did not result in increased phytoestrogens in alfalfa. Therefore, if plant disease measures have been implemented, the concern for phytoestrogens interfering with female reproductive performance is low.
Besides potential issues with the cattle, grazing alfalfa can cause issues with the plant. There are two types of alfalfa: those for hay and those for grazing. This does not mean that you cannot use either type for the other situation, but it does mean that additional care should be taken. Varieties for hay production are bred to produce high quality tonnage based on infrequent complete harvesting of above ground plant material, which then allows the plant to regrow and put down more energy reserves into the roots. But hay production varieties have poor grazing tolerance due to the frequent removal of above ground plant material by the cattle. Hay varieties can also have more bloat potential. In contrast, grazing varieties were bred to withstand more frequent removal of above ground plant material by cattle resulting in a more persistent stand. Grazing varieties are also less bloat prone, but not bloat free. The grazing management system needs to be adjusted to the type of alfalfa.
Alfalfa regrows from the crowns which are at the soil surface and heavy hoof traffic can damage the crowns. Grazing management plans need to take this into account and consider such things as soil moisture conditions and repeated trampling of plants. Removing cattle if the soil becomes soft from moisture and rotating cattle to new areas of the field to reduce trampling are ways to minimize damage to crowns.
In contrast to overnight frost, a killing freeze followed by cold days can significantly reduce bloat problems, but also reduces the nutritive value of the forage. Grazing killed alfalfa should occur in the few days/weeks after the killing freeze to capture as much of the nutritional value as possible. Additionally, hoof traffic on frozen ground causes less damage to alfalfa crowns.
September is calving season for many fall-calving herds. Nutritional management of fall-calving cows is a little different than spring-calving herds throughout the production cycle. Peak energy, measured as total digestible nutrients (TDN), and protein requirements occur early in lactation at about 1 to 3 months after calving (Figure 1). For spring-calving cows, the calving season is typically aligned with peak energy and protein requirements occurring at the time pastures green up such that the young tender grass with high protein and digestibility can meet those nutrient requirements. For fall-calving cows, the ability of pasture to meet peak energy and protein requirements is highly dependent upon the forage species. Cool-season forages such as fescue regrow in the fall when temperatures begin to cool down providing highly nutritious grass to meet the requirements of the cow during this time. However, warm-season forages are slowing growth as temperatures decline and becoming dormant having much lower nutritive value and less ability to meet the nutrient requirement of cows in early lactation. But, stockpiled bermudagrass or native grass with protein supplementation can effectively meet the nutrient requirements of fall-calving cows. And planting cool-season annual forages can easily meet the nutrient requirements of lactating beef cows, and can even be used as a supplement to warm-season pasture by limiting the time cows graze the annuals each day.
Fall-calving cows have a couple of advantages. One advantage is the climate which is typically dry and cool, which does not increase maintenance requirements like cold and wet conditions in the spring. The second advantage is that fall-calving cows came through the summer grazing months without a nursing calf and are usually in very good body condition; 6 or better. Greater body condition at calving allows these cows to lose some condition without detrimental effects on reproductive performance. The breeding season for fall-calving cows is usually late November through December such that cows are pregnant before bad winter weather. Pregnant cows are unlikely to lose a pregnancy due to poor body condition, which allows fall-calving cows to lose some condition through the winter. This works financially because cows will be able to regain lost condition inexpensively on pasture next summer. It is not advisable to let spring-calving cows lose condition through the winter leading up to calving as it is not economically feasible to regain condition between calving and breeding seasons.
A possible disadvantage of fall-calving cows is that some feeds available in the fall of the year may not be suitable. As displayed in Figure 1, the energy requirement is much greater than the protein requirement and is expensive to provide because of the tonnage necessary. Thus, feedstuffs with lower digestibility may not be good options. For example, corn stalks can readily meet the nutrient requirements of spring calving cows after weaning, but may not work for fall-calving cows except for a few weeks early on when cows are consuming leaves, husks, and down ears. Other feeds such as ammoniated wheat-straw will require significant energy supplementation to meet energy requirements of cows in lactation and high levels of ammonia intake may have negative effects on reproductive performance.
Fall-calving cows can be especially challenging in a drought. Forage production was less than usually so cows are thinner than usual at calving and do not have the surplus fat to lose condition through early lactation and breeding. Additionally, alternative forages such as crop residue or wheat straw will require substantial supplemental grains and byproducts to meet nutrient requirements. Meeting nutrient requirements during the time between calving and breeding is critical if cows are only in moderate body condition because the loss in pregnancy rate will impact the ranch for several years to come. Planting cool-season annuals is an option, but requires fall rains to get the crop established, and if not established early in the fall, forage growth will be too little for winter grazing.
Plan on feeding a considerable amount of supplement to fall-calving cows during fall and winter in drought years. Conventional feedstuffs are likely to be expensive as demand is high and supply may be low. Look for alternative feeds such as failed crops, spent grains from local breweries, fruit and vegetable waste from local supermarkets, etc. Any untapped waste stream that provides rumen-digestible, safe feedstuff that is less expensive per unit of energy (TDN) will be advantageous during drought.
As we move into late summer and early fall, we begin think about weaning time. Weaning can be a stressful event and there are some techniques such as fence line weaning to reduce that stress, but the focus of our discussion today is feeding those weaned calves. Stressed calves and calves that are not used to a feed bunk do not readily consume feed. Getting those calves on feed is critical requiring a good diet and proper feed management. A starter diet should include feeds that calves are familiar with such as hay and highly palatable feeds such as dried distiller’s grains. Feeds such as corn silage are great for growing cattle but can turn calves off from eating because it has a different smell and taste. Silage can be incorporated slowly after calves are eating well. Feed needs to be delivered in a manner that encourages feed intake. A good way to do this is to provide feed in an open bunk perpendicular to the fence line. An open bunk does not require calves to put their head into or through a stanchion that might hinder feed consumption. Placing the bunk perpendicular to the fence line requires bawling calves to walk into the bunk when pacing the fence.
One important consideration for backgrounding calves is to assess feed resources. Home grown forages and grains are typically used, but purchased feeds can also be used. An assessment of the quantity and quality of feeds needs to be completed to know whether enough feeds are available for the entire length of the backgrounding period and to formulate diet to meet the production goals. Feeding calves to achieve the correct weight at the correct time is critical for marketing and profitability. There are a couple of methods to formulating diets for backgrounding calves. One method is to formulate a diet with greater than 50% forage which is fed to appetite. This method requires less management and equipment. This method can be implemented with a predetermined amount of grain feed in bunk and free-choice hay, but may have better results as a totally mixed ration fed in a bunk. The second method is to formulate a diet with less than 50% forage which is fed in limited amounts. The advantage of this method is that high energy feeds, which are typically less expensive on a per unit of energy basis, are used reducing the cost of gain. However, this method requires more intensive management in that diet formulation needs to be more precise and correct feeding management in the form of bunk space and accurate feed delivery. Implementation of the limit-feeding method necessitates the use of a totally mixed ration and feed mixing equipment.
Backgrounding fall-weaned calves instead of selling calves at weaning can have a couple of drawbacks that can be overcome with time. Calves will likely lose weight during the first few days after weaning due to stress and reduced feed intake. Getting calves to regain the lost weight will have a high cost of gain requiring a backgrounding period long enough to reduce the overall cost of gain. Additionally, as the fall run of calves gets into full swing, the price of calves will decrease requiring calves to gain enough weight to more than offset the reduced price. Thus, deciding on the proper market time and weight are necessary to profit from backgrounding, which will influence the diet and feeding program necessary to meet those goals.
As we move into the heat of summer, forage plants begin to reach maturity which means that the amount of lignin deposited in the plant cell wall increases and the amount of protein decreases. This is a continual process as the plant matures, but when the plant begins to put up seed heads is usually when forage digestibility begins to decline, although this can be forage species dependent. Lignin is not readily digested by rumen bacteria, and it also inhibits digestion of the rest of the plant cell wall. Additionally, the decrease in protein concentration becomes limiting for growth of rumen bacteria which decreases their ability to digest plant material. The increase in lignin and decrease in protein combine to reduce forage digestibility which in turn decreases the amount of forage the animal can consume. This becomes a double-edged sword in that the animal does not get as much nutrition from each bite and cannot eat as much.
It is impossible to remove the lignin once it is deposited in the plant cell wall. The only management strategy is to slow down the rate of plant maturation by frequent grazing. To accomplish this effect, cattle must be moved to a new paddock every day which is not practical for many ranches. Also, there is discrepancy as to whether frequent grazing/rest periods has the same effect with all forage species in all regions of the country.
Even though maintaining low lignin concentration of forages is not always practical, increasing the protein supply to rumen bacteria is beneficial and practical. Digestibility of forage can be improved with protein supplementation when forages mature in late summer. Previous research at Kansas State University indicates a 13% improvement in digestibility of native prairie hay with protein supplementation. Available protein sources that work well are soybean meal and cottonseed meal that provide large amounts rumen degradable protein meaning that this protein is available to the rumen bacteria. Other feedstuffs such as distiller’s grains are lower in rumen degradable protein and higher in energy and are better suited when both energy and protein need to supplemented.
Protein supplementation can be easily implemented in many ranch situations due to the ability of the ruminant animal to recycle nitrogen within the body. Because of this ability to recycle nitrogen back to the rumen, beef cows and stocker calves can be supplemented with a high protein feed every 3 to 6 days rather than daily with similar benefits in forage digestion. Be sure to monitor the maturity of forage plants in pastures over the next few weeks to determine the appropriate time to begin protein supplementation. Work with your veterinarian or county extension agent to determine the appropriate time and amount of protein supplement.