Nutritional Energy Requirements for Beef Cattle

Equally ruminant animals, cattle have a digestive system that allows them to digest roughage, like hay and grass, and concentrates such as barley grain or dry distillers' grains, through the action of a diverse microbial community in the rumen. Cattle require energy, protein, water, vitamins and minerals in suitable amounts to provide acceptable nutrition. Requirements will differ depending on the animal's class, age, condition, and stage of productionⁱ. Feed costs, including both grazed and conserved feed, are the greatest expense associated with beef cattle operations. Since nutrition is frequently the most important factor influencing reproductive operation, managing feed resources at a reasonable cost to consistently achieve high reproductive rates volition aid ensure profitability for beef cattle operations. In the backgrounding and feedlot sectors, feed costs and feed conversion efficiency significantly affect profitability. Beyond all sectors of the beef cattle manufacture, feed quality, toll, and efficient digestion/absorption/conversion are key factors in animal health, reproduction, performance and profitability.

On this Folio

• Key Points
• The Ruminant Digestive Arrangement
• Key Nutrients Required past Cattle
  • Energy
  • Protein
  • Water
  • Minerals
  • Salt
  • Vitamins
• Feed Sources and Quality - Impact on Nutrition
• Factors Affecting Nutrient Requirements
• Conclusion
• Definitions

Fundamental Points

• Gradual nutrition changes (over ii to 3 weeks) are necessary to permit the rumen microbial population to adjust to changes in the diet
• Young, actively growing forages and legume blends can ofttimes meet the nutritional requirements for normal growth and maintenance of cattle herds.  Mature pastures, crop residues, or other low-quality forages may have reduced nutritive value, requiring supplementation of protein, free energy or additional vitamins and minerals to maintain optimal wellness
• Energy is necessary for maintenance (feed digestion, core body functions, and activity requirements) and to support growth, lactation and reproduction. It accounts for the largest proportion of feed costs and is the food required past cattle in the largest corporeality
• Neutral detergent fibre (NDF) and acid detergent fibre (ADF) are indicators of the amount of fibre in a forage. Higher values indicate poorer digestibility and voluntary intake may be reduced
• Protein is required for maintenance, growth, lactation and reproduction. Information technology is a component of muscles, the nervous arrangement and connective tissue
• Water is an essential food for cattle, accounting for between l and eighty % of an animal's live weight. Insufficient water intake reduces animal performance faster and more dramatically than any other nutrient deficiency
• At to the lowest degree seventeen minerals are required by beefiness cattle and are divided into two groups: macrominerals and microminerals
• Although minerals are required in small amounts for optimum beef cattle health, a deficiency can cause significant reductions in growth, allowed function and reproduction
• Mineral needs will vary between herds based on many factors, including h2o and feed sources, stress, animate being type and stage of product. There is no "one size fits all" mineral type or program
• Mineral toxicity may be indicated by decreased creature performance, anorexia, weight loss and diarrhea
• Vitamins support many vital metabolic processes in cattle
• Forage is an economical source of nutrients; however, feed quality and mineral content tin vary widely, so feed testing and appropriate supplementation may be necessary to meet nutritional requirements
• Most forage species take the highest quality at the vegetative stage, when leaves are lush and green, and stems are young and supple. At this stage, these forages may be able to supply most of the diet that the cattle require
• Noesis of forage quality and animate being requirements is necessary to formulate rations that volition support and maintain a high plane of nutrition
• Nutritional requirements of beef cattle are influenced by the stage of product

The Ruminant Digestive System

Ruminant animals have a complex digestive system with a four-chambered stomach. Each chamber (reticulum, rumen, omasum and abomasum) plays a role in digesting livestock feeds. Microorganisms colonize the reticulum and rumen (often collectively termed the reticulo-rumen) and allow cattle to digest feedstuffs loftier in fibre, such every bit grasses, straw and other forages. Balancing the requirements of the rumen microorganisms and the brute is essential for animal performance.

Cattle take large bites of feed and consume with little chewing. Subsequently, they regurgitate masses of feed support the esophagus and into their mouths, where it is chewed into smaller pieces and swallowed. This process is known as rumination or chewing cud. Between 60 to 70% of digestion occurs in the reticulo-rumen, which acts like a fermentation vat where bacteria and protozoa catechumen virtually of the plant fibre and carbohydrates to acetic, propionic or butyric acid (short chain fatty acids) and convert much of the ingested protein to microbial protein. The short chain fat acids are absorbed through the reticulo-rumen wall and are used as energy in body tissues. Some of the carbohydrate, starch and pectin may pass through the rumen and are then digested in the abomasum and small intestine.

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Microbes in the rumen require an anaerobic (oxygen free) surroundings with a slightly acidic pH range (6.5 - 7.0), a supply of protein (or non-protein nitrogen) and carbohydrates to feed the microbial population². The type of feed influences growth of the bacteria. Different rumen microbes prefer different types of carbohydrates (starch, cellulose, hemicellulose, starch, and pectin) and will increment or decrease in number depending upon the ratio of different carbohydrates inside the diet. Because the various bacteria and protozoa digest cellulose, hemicellulose and starch differently, sudden changes to cattle diets tin can affect rumen activeness. For example, a rapid change to a high energy diet with more grain can result in digestive disorders such equally bloat and acidosis. Long periods of acidosis tin also damage the rumen wall, potentially assuasive bacteria to colonize the liver, causing abscesses³. For these reasons, gradual changes (over two to 3 weeks) are necessary to permit the rumen microbial population to arrange to changes in the nutrition. Nutrients that are not used for the microbes' growth laissez passer out of the reticulo-rumen to supply nutrients for the beast'southward growth and reproduction.

Key Nutrients Required by Cattle

Young, actively growing forages and legume blends can often meet the nutritional requirements for normal growth and maintenance of cattle herds. Mature pastures, crop residues, or other depression-quality forages may have reduced nutritive value, requiring supplementation of protein, energy or additional vitamins and minerals to maintain optimal health. Sure nutrients are required in the daily ration, while others can be manufactured and stored in the torso.

Cattle require v cardinal nutrients:

• free energy
• poly peptide
• h2o
• minerals
• vitamins

Energy

Free energy is necessary for maintenance (feed digestion, cadre body functions, and activity requirements) and to support growth, lactation, and reproduction^1. It accounts for the largest proportion of feed costs and is the nutrient required by cattle in the largest amount. The components of feed that determine its free energy content include carbohydrates, fats and proteins. On a feed test, free energy content is usually expressed as total digestible nutrients (TDN); withal, more than precise terms such as metabolizable free energy (ME) or net energy (NE) for maintenance (NE_thou) or product (NE₁₀₀₀) may exist preferred by nutritionists. These terms better reflect the amount of energy from feed that contributes to animal productivity. Free energy deficiency caused past depression intake or poor feed quality volition limit growth, decrease milk production, reduce body condition, and (depending on timing and duration) may accept negative consequences for reproduction.

Gross energy (GE) is the total amount of energy in the feed. Just non all this free energy is available to the animal. Feed energy is lost as it passes through the brute and is excreted as feces, urine, various gases, and rut. These losses are a normal consequence of feed digestion and the amount of energy lost at each step differs based on the quality of the feed. Digestible energy (DE) provides an indication of the portion of energy that the animal tin assimilate, with the help of the rumen microbes. Metabolizable energy (ME) is the amount of energy bachelor to the creature for metabolism and body functions after losses in free energy from rumen fermentation (carbon dioxide, methane) and urine have been accounted for. Internet energy (NE) is the amount that is available to the animal to maintain itself, grow, produce milk and reproduce.

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Neutral Detergent Fibre (NDF, %) indicates the amount of fibre content in the establish. High levels of NDF (higher up 70%) will restrict beast intake. More mature forages will have college NDF levels.

Acid Detergent Fibre (ADF, %) measures the least digestible portions of the forage plants, such every bit cellulose and lignin. High ADF indicates poor digestibility of the feed. High quality legumes generally have ADF values between 20-35%, while grasses can range from thirty-45%.

Neutral detergent fibre (NDF) and acid detergent fibre (ADF) are indicators of the corporeality of fibre in a provender. College values signal poorer digestibility and voluntary intake may exist reduced.

NDF is a measure of the "bulkiness" of the nutrition and is mainly hemicellulose, cellulose, and lignin but due to limitations in the assay it also includes a portion of the poly peptide and insoluble ash in the plant. When NDF increases, animals swallow less. ADF measures cellulose and lignin and is an indication of digestibility and energy intake. When plants mature, lignin content increases, resulting in higher ADF and reduced digestibility. Feeds loftier in ADF are less digestible than those high in starches and sugars. The starches and sugars in feed are classified equally not-structural carbohydrates (NSC). Even in forages, NSC are an of import source of energy.

Protein

Poly peptide is required for maintenance, growth, lactation and reproduction. It is a component of muscles, the nervous organization and connective tissue¹ . Protein requirements depend on cattle age, growth rate, pregnancy and lactation status. Immature, growing cattle, as well as those in late pregnancy or lactation, have increased protein requirements.

Most poly peptide that ruminants ingest is cleaved down by the rumen microorganisms and resynthesized equally microbial protein. Forages contain crude poly peptide (CP) in ii forms. The greatest portion of protein in forage is referred to as true poly peptide, but forages likewise contain depression amounts of not-protein nitrogen (NPN), which rumen microbes can use to synthesize microbial protein.

True protein in forages can exist further classified equally rumen undegradable poly peptide (RUP or rumen bypass protein) and rumen degradable protein (RDP). RUP are peptides and amino acids that are digested in the abomasum and absorbed in the pocket-sized intestine, while RDP is degraded or broken down by the microbial population in the rumen into ammonia and volatile fat acids. Microorganisms in the rumen combine the ammonia supplied by RDP or other non-protein nitrogen sources (eastward.g. urea) with rumen digestible carbohydrates to synthesize microbial crude protein (MCP). MCP is digested in the abomasum, with the resultant amino acids captivated in the pocket-sized intestine. The corporeality of protein that reaches the small intestine depends upon the availability of RDP and the rumen digestible carbohydrate. If free energy is deficient in the diet, surplus ammonia is converted to urea in the liver and and then lost through urine. If protein is deficient in the diet, digestibility of fibre decreases due to diminished microbial activity and muscle will be degraded to run across the animal's requirements for amino acids for cadre body functions.

Microbial protein makes up shut to 70% of all protein absorbed from the pocket-size intestine and the protein contributions from microbes may exist close to 100% for cattle fed depression-quality forage.

In most moo-cow-dogie diets, forages with adequate digestibility will provide plenty MCP to come across the cows' requirements. But, for animals with higher protein demands, like growing calves or lactating cows, it can be beneficial to feed proteins that bypass the rumen and are absorbed in the pocket-size intestine, improving protein bioavailability. Actress protein can be provided by feeds that are loftier in RUP, similar alfalfa dehydrated pellets, distillers' grains, or alternative feeds similar canola meal. Most forages have higher levels of RDP, specially legumes.

During summer months, while forages and legumes are actively growing, they may supply up to xx% rough poly peptide (CP) with a high level of RDP, but during the wintertime, poly peptide levels drop off dramatically. Native pasture, for example, may examination every bit low as iii-7% CP. Putting up good quality feed is cardinal to supplying the beef herd with adequate quality fodder sources through the winter⁴.

Water

Water is an essential food for cattle, accounting for between fifty and 80 percent of an beast's live weight. Insufficient water intake reduces brute performance faster and more dramatically than any other nutrient deficiency. For livestock to maximize feed intake and production, they require daily access to palatable water of acceptable quality and quantity. Factors that decide water consumption include air and water temperature, humidity, wet content of the feed/forage, cattle type (dogie, yearling, balderdash, moo-cow), the physiological land of the animal (gestation, maintenance, growing, lactating) and h2o quality.

Total dissolved solids (TDS) is the main indicator of water quality and is a measure of dissolved inorganic salts in water. TDS is impacted by high or low pH levels, sulphates, nitrates, salinity, excessive mineral levels, algae and leaner. Testing water sources to ensure that cattle have access to adequate amounts of quality h2o is of import.

The iv main functions of water in the body are:

• to help eliminate waste product products of digestion and metabolism
• a major component of secretions (milk, saliva) every bit well as individual and fetal growth
• every bit an aid in body's thermoregulation processes through evaporation of water/sweat from the skin's surface and respiratory tract
• to regulate claret force per unit area⁵

Read more than most water requirements for beef cattle hither.

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Minerals

At least seventeen minerals are required by beef cattle and are divided into two groups: macrominerals and microminerals. Macrominerals are those required in relatively large amounts for bodily functions, while micro or trace minerals are required in much smaller amounts.

The 7 macrominerals required past cattle are calcium (Ca), magnesium (Mg), phosphorus (P), potassium (K), sodium (Na), chlorine (Cl) and sulphur (S). Macrominerals are required in amounts over 100 parts per million (ppm) and are often expressed on a percent (%) dry thing (DM) ground of the animate being's diet.

Beef cattle require x microminerals, also referred to as trace minerals. These microminerals, required in relatively small amounts are unremarkably expressed in parts per million, (ppm) or mg/kg, rather than as a percentage of the diet. They are chromium (Cr), cobalt (Co), copper (Cu), iodine (I), iron (Iron), manganese (Mn), selenium (Se), and zinc (Zn).

Producers strive to provide adequate levels of macro and microminerals without over-supplementing, which increases costs, tin create nutritional antagonisms, and increases potential for mineral loss through manure and urine⁶.

Minerals are required for several functions:

• skeletal development, bone, tooth formation and maintenance (includes Ca, P, Mg, Cr)
• free energy, growth, amnesty, and reproduction (includes P, Cu, Zn, Mn, Se)
• milk production (includes Ca and P)
• nervous system part and carbohydrate metabolism (Mg, K, Na, Cl, S, Co, I, Fe)

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Although minerals are required in relatively small amounts for optimum beef cattle health, a deficiency tin cause significant reductions in growth, immune function and reproduction. The concentration of individual minerals in forages varies profoundly depending on soil, plant, and management factors. It is important to include mineral analysis of forages every bit function of regular feed testing. There are also several interactions that tin can occur between minerals, vitamins and h2o or feed sources that can limit availability or absorption. Equally a result, the minerals that are actually available to the cattle may be much lower than predictable because of these interactions. Fifty-fifty though concentrations found in forages may appear to be sufficient, availability to the animal may exist significantly less. This can cause deficiencies which may not exist noticed by producers until a meaning reproductive or health issue arises.

In this web log, a Saskatchewan producer explains the issues that he experienced with copper deficiency.

Dr. Cheryl Waldner, NSERC/BCRC Industrial Research Chair in 1 Health and Production-Limiting Diseases, and Professor at the Western College of Veterinary Medicine explains that outset and second calf heifers are most likely to exhibit signs of copper deficiency, such as lower conception rates. The cost of open cattle tin can quickly impact profitability. Waldner suggests that a properly counterbalanced, palatable mineral mix be offered yr-round to ensure optimal herd health and fertility.  Recent research in Saskatchewan revealed that forages sampled in spring and fall contained inadequate levels of copper and zinc for beef cows and growing calves in all soil zones. Additionally, up to 43% of the cows involved in the study were deficient in copper. Producers may observe some early on signs of copper deficiency manifesting every bit a brownish or crimson tinge in black haired cattle.

Other issues that tin arise due to mineral deficiencies include grass and winter tetany, white muscle disease, weak bones, hairless calves, goiter, scours, foot rot, retained placentas, depression weaning weights, and reduced fertility.

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Trace mineral supplements are divided into three groups: inorganic, organic and hydroxy trace minerals.

Inorganic minerals are bonded to an inorganic molecule such as sulphate or oxide. They are usually less expensive but often accept more than variability in formulations and are less bioavailable. Inorganic minerals are ofttimes a first choice for producers due to affordability but may sacrifice availability and absorption. The absorption of inorganic mineral from the gastrointestinal tract can be less than 5 pct⁷.  In certain instances, such equally with copper, inorganic minerals may exist more prone to antagonisms with other minerals⁸. Merely feeding more inorganic mineral to starting time these potential issues will not exist successful and may cause more than problems if levels of item minerals get too high.

• Organic (chelated) minerals are bonded to a carbon containing molecule. These are usually more expensive but have improved assimilation and availability to the creature. Producers generally use chelated minerals if mineral antagonisms exist in their area, such as high molybdenum or sulphur, which reduces copper availability. Chelated minerals are likewise used when animals are stressed, such as during weaning, or to ensure a loftier nutritional plane for procedures such every bit synchronization or artificial insemination on heifers.

• Hydroxy trace minerals have a crystalline structure that protects metal ions and allows trace minerals to bypass rumen digestion, thereby increasing bioavailability. Frequently available at a mid-range cost, they are beingness utilized by some producers for cattle in high stress situations, such every bit weaning or artificial insemination.

With improved trace mineral absorption, producers report heavier weaning weights, increased average daily proceeds, improved reproductive efficiency, improved calving outcomes, and fewer wellness issues. Some also report reduced incidence of pinkeye, foot rot, scours and respiratory problems.

Mineral needs will vary between herds based on many factors, including water and feed sources, stress, animal type and stage of product. There is no "one size fits all" mineral type or program. Many mineral mixtures are available on the market, from loose mineral that can be offered costless choice or mixed into a ration, to various molasses-based lick tubs that contain vitamins, minerals, and often some poly peptide.

When rations comprise grass hay, alfalfa, or a mixture of the 2, calcium and phosphorus usually need to be supplemented in a 1:1 ratio (ane part calcium to ane office phosphorus). When feeding cereal provender rations, such as oat or barley greenfeed, a 2:1 or even 3:one mineral mixture may be required to provide a balanced mineral mixture. Be sure to consult with a nutritionist to ensure proper supplementation.

Producers must monitor animals for signs of deficiencies or potential toxicity, and work with their veterinarian and nutritionist to ensure adequate levels and to right whatsoever issues. Mineral toxicity may be indicated by decreased beast operation, anorexia, weight loss and diarrhea. It tin lead to urinary calculi from excess phosphorus or inadequate calcium to phosphorus ratio, grass tetany from excess potassium leading to reduced absorption of magnesium, and polioencephalomalacia from excess sulphur. Some minerals such equally copper, tin become "tied upwards" or spring to other minerals present in feed and water. In these instances, the mineral will not be available to the cattle in the amounts required. If producers are using feed tests to balance mineral needs, animals may still be scarce due to reduced bioavailability.

An brute'southward diet or ration will determine the blazon of mineral mix required to see animal requirements. Grass is often low in calcium, phosphorus, magnesium and sodium, while alfalfa or other legumes are generally higher in calcium.

The following label contains the breakdown of a loose mineral that would be considered a 3:i calcium to phosphorus ratio and may be used by producers feeding cereal greenfeed forages.

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Cattle will oftentimes demonstrate a preference for certain mineral mixes or molasses lick tubs, which tin can create challenges in terms of daily intake when feeding free option. While recommended mineral intake is about threescore grams (2 ounces) per head per day, when fed free choice some cattle will over-consume mineral, while others may avoid information technology birthday. Monitor the herd to decide which cattle are frequently at the mineral stations and which cattle may not be consuming adequate amounts. Some producers study better intake when they offer choices of different mineral mixes, such every bit loose and lick tubs. Others report that moving the mineral stations a lilliputian farther from water sources to encourage grazing on less utilized areas of pasture caused mineral consumption to drop off slightly.

Ensure that there are enough stations for the number of cattle; a mutual recommendation is i mineral station for every twenty-30 head. When feeding cows with calves at side, more stations may be necessary to ensure that the calves have access, as ascendant, mature cows will oft outcompete calves for mineral. When possible, piece of work with a nutritionist to formulate an appropriate mineral alloy for each functioning.

In the following video from Beef Research School, Dr. John McKinnon explains what factors producers should consider when designing a mineral programme. He also provides tips for achieving ideal consumption.

Salt

Examples of common salt blocks in various formulations. Photo credit Tamara Carter.

Although the salt requirement for beefiness cattle is relatively depression, cattle will seek out table salt. Loose salt mixed into mineral blends can assist increase intake to ensure acceptable amounts are being consumed. Table salt tin as well exist used to encourage cattle to graze underutilized areas of pastures, past placing farther away from water and areas where cattle tend to congregate.

Many producers choose an iodized common salt block to ensure acceptable iodine intake, specially in areas known to take iodine deficient soils. The normal requirement for iodine in a beefiness cattle nutrition is 0.5 ppm of the total diet and tin usually be provided with iodized salt blocks. Additional iodine may be necessary if feeding cover crops such every bit brassicas including turnips, rapeseed or kale which contain compounds that inhibit iodine uptake from the gut. While higher toll, salt blocks that contain trace minerals such equally copper, zinc, cobalt and selenium may exist used for herds that have experienced problems with foot rot. While these salt blocks tin supply pocket-size amounts of certain minerals, additional supplementation with loose or lick tub formulations may still be necessary to provide and maintain adequate mineral levels.

Vitamins

Vitamins back up many vital metabolic processes in cattle. They are inorganic compounds that are required in small-scale amounts. The age and product status of the creature will bear upon vitamin requirements. Vitamins A, D, E and Yard are fatty soluble and are stored in the animal's fat tissue and liver. Because of this, they do not demand to be supplemented daily if the beast has acceptable reserves. These vitamins are present in feed sources and are responsible for fundamental metabolic processes within the brute, and thus are important to monitor to ensure deficiencies practice not develop. Fresh, leafy forages generally comprise adequate levels of vitamin A and E, however, drought, forage processing and extended storage periods can reduce levels. While supplementation of A, D, E and K may not be required during the summer months, supplementation is recommended during winter months, specially prior to calving. The main functions of vitamins A, D, East and K are:

• Vitamin A - essential for bone, teeth and nerve development, eyesight, kidney function, and soft tissue maintenance. Vitamin A is oftentimes depression in newborn calves, and young animals generally accept smaller reserves than older animals. Deficiencies, which may manifest initially as rough hair coat, dull eyes, diarrhea and pneumonia, can progress and crusade reduced bone development and density, decreased fertility, dark incomprehension, reduced feed efficiency and increased susceptibility to disease. Cows with deficiencies may abort, have weak calves, or be difficult to settle. Vitamin A is stored in the liver, but without an exterior source, these liver stores will be depleted after two to three months. Carotene is converted to vitamin A from beta carotene, found in dark-green forages and yellow corn,⁹ in the pocket-sized intestine. Conditions that may crave supplementation include periods of greater stress, such as weaning or transportation, feeding stored forages during winter that have reduced carotene levels, and feeds or water with higher nitrate levels.
• Vitamin D - required for calcium and phosphorus metabolism, as well equally teeth and bone development. Information technology is synthesized by the dominicus or by eating sun cured forages. Early signs of deficiency include poor appetite, decreased growth in calves, weakness, strong gait and laboured breathing. Soft bones, rickets, and swollen joints develop if deficiencies go on. Pregnant animals with a vitamin D deficiency may abort or take weak, deformed or stillborn calves.
• Vitamin East - required for muscle evolution and occurs naturally in feedstuffs.
• Vitamin K - required for blood clotting and is ordinarily sufficient in green forages. Rumen bacteria generally make sufficient quantities of vitamin K from feed sources. Feeding some clovers, especially if mouldy, interferes with the production of vitamin K due to a compound called dicoumarol present in clover.

Vitamin C and the B vitamins (thiamin, niacin, choline) are water soluble. Calves receive vitamin B from milk, and once the rumen becomes functional, these vitamins are synthesized by rumen microorganisms and practice not usually require supplementation unless energy and protein balance in the diet is not adequate^half-dozen.

Feed Sources and Quality - Affect on Diet

Cattle tin employ a wide multifariousness of feedstuffs. Different feeds have dissimilar benefits and limitations when information technology comes to supplying nutrients:

• forages - high in fibre, lower in energy, with varying protein content; examples are hay, grass, greenfeed, silage
• grains - high in energy and low in fibre, moderate to high protein content; examples are corn, oats, barley, wheat
• oilseeds - high in poly peptide, high in energy, high in fat, variable fibre content; examples include soybeans, canola meal
• by-products - variable nutrient content, may be high moisture; examples are distillers' grains, bakery waste, grain screenings, hulls

Each of these feeds provides unlike nutrients, with each nutrient fulfilling specific roles in cattle growth, maintenance and reproductive health. Balancing nutrient costs with the intended direction objectives for the cattle is key. While forages are a foundation of well-nigh feeding systems, backgrounders and feedlots will utilise more grains and by-products in their rations. In the moo-cow/calf sector, forages make up the largest portion of the animals' diet, both while grazing during summer and in the winter while consuming conserved feeds. Cattle producers often utilize grains and culling feeds to provide adequate nutrition and reduce feed costs. Optimizing the growth charge per unit of rumen microbes to better fermentation and microbial growth requires a balance of feedstuffs.

Forage is an economical source of nutrients; withal, feed quality and mineral content tin can vary widely, then feed testing and appropriate supplementation may be necessary to meet nutritional requirements. Forage quality directly impacts animal performance, growth, reproduction and profitability. Most forage species take the highest quality at the vegetative phase, when leaves are lush and greenish, and stems are young and supple. At this stage, these forages may be able to supply most of the diet that the cattle require. Harvesting and feeding loftier quality hay tin reduce the corporeality of supplemental minerals and vitamins that may be required.

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The level of minerals in a forage will depend on many factors including soil type, plant species, stage of growth, the weather, and overall direction of the stand. Maturity at harvest, as well every bit harvest techniques and storage will too impact forage quality. In improver, the absorption of trace minerals from forages in the gastrointestinal tract tin can be very low. As Dr. John McKinnon explains in this blog, combative interactions between minerals can reduce levels absorbed fifty-fifty further, sometimes even to zero.

Low quality forages mostly reduce voluntary intake, which can upshot in poly peptide and energy deficiencies. When high quality forage (vegetative growth) is consumed, dry out matter intake tends to be 2.5-3.0% of live body weight. When provender is of lower quality, dry matter intake tin driblet closer to 1.8% of body weight, reducing protein, energy, and mineral consumed. In some instances, when the creature's needs are non being met (e.g. feeding a ration containing very low quality forages or harbinger during cold temperatures in winter), they may actually over-swallow low quality feed, every bit they attempt to derive plenty energy from the feed. This over-consumption of beefy, depression quality feed can cause compaction, which prevents feed from moving through the digestive tract and tin can cause expiry. Analyzing feed samples volition provide an indication of poly peptide and free energy levels available. While feeding lower quality feedstuffs tin can exist an economical fashion to stretch feed supplies, producers must monitor consumption and brute condition to avert potential problems with under or over consumption of depression quality feed. Use of tools such as the Winter Feed Cost Comparison calculator tin can assist producers with cost comparisons.

Knowledge of forage quality and animal requirements is necessary to formulate rations that volition support and maintain a loftier plane of diet. While most producers recognize that grazing forages can provide an economical source of nutrition, the human relationship betwixt forage quality and profitability is often unappreciated. Producers must manage grazing in response to environmental atmospheric condition and pasture growth during the season to avoid either overgrazing, which reduces fodder yield, and under grazing which tin can lower the overall provender quality due to over-mature vegetation and may also increase forage waste. Proper grazing management can support both nutrition and profitability.

Factors Affecting Nutrient Requirements

Stage of Production

Nutritional requirements of beef cattle are influenced by the phase of production. This production cycle, which is based upon a well-managed, healthy moo-cow in good condition (Body Condition Score = iii) maximizes profitability past producing a calf every 365 days. The annual product cycle, based upon platonic length of time for each stage, includes:

1. Calving, postpartum, early on lactation (twenty-four hours 0 to day 82)
2. Conception, early gestation, late lactation (solar day 83 to day 199)
3. Mid gestation (mean solar day 200 to day 274)
4. Late gestation, pre-partum (day 275 to twenty-four hour period 365).

Phase 1 - begins at calving. This is the period of greatest nutritional demand for the moo-cow. She must lactate, repair her reproductive tract, resume heat cycles, breed, and if she is a young cow, she must also continue growth and development. Her voluntary feed intake is highest at this point and as this blog explains, she requires a high energy and protein diet of at least 62% TDN and 11% CP. If she is non fed to meet nutritional needs, she will lose weight and may not rebreed.

Phase 2 - begins with conception. The cow is at present supporting herself, her calf (through lactation) and her fetus. Nutritional demands are still loftier equally she reaches meridian lactation only are lowered by 8-13% compared to the commencement phase. Cows that produce more milk will have higher food requirements. The fetus is modest, and its growth is slow, but cows and heifers oft lose weight during this fourth dimension.

Phase 3 - is when the cow is in mid-gestation. Immediately afterwards calves are weaned, nutritional needs are at their everyman due to the end of lactation. Energy and protein requirements drop by upwardly to 35% when compared to the peak demand. Fetal growth remains irksome, and voluntary feed intake is the lowest during this period. This is the best time to put weight back on cows to help them gain condition^x. Encounter the body condition  information to learn more than about how to ensure beef cattle are in ideal condition.

Stage 4 - is the terminal phase prior to calving, and cows must be in good torso condition to give birth to a healthy calf, produce milk and re-breed quickly. Energy and protein needs increment past twenty% compared to mid-gestation. During this period, the fetus tin gain up to 60 pounds and the placenta is growing likewise. Near 75% of fetal growth occurs during this phase¹¹. Cows need to proceeds 0.5 kg (one lb) to 0.68 kg (1.5 lbs) per day, while weight gain for heifers should target twice that amount. The cow has reduced rumen capacity due to the growth of the calf, so a reduction in feed intake usually occurs in the latter portion of this stage.

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Producers ofttimes change their feeding strategies during the annual production bicycle of the beefiness moo-cow to align with her free energy and protein needs as she moves through the cycle. For example, lower quality feeds such as straw reduce costs during Stage 3, when the cow'due south nutritional requirements are at her everyman. In Phase 4, every bit the rumen has less room for feed due to the growing fetus, she will do good from college quality feed such as good quality alfalfa hay or some grain to provide actress energy. A common rule of thumb is 55-threescore-65% for total digestible nutrients (TDN) and 7-nine-11% for rough poly peptide (CP) for mid gestation, late gestation, and lactation. More than information on nutritional requirements can be can exist found here.

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Producers oft divide the herd into different feeding groups to tailor the feeding plan to provide an acceptable level of nutrition. These groups may include:

Group 1 - Mature cows in good condition - Average quality hay supplemented with grain or pellets, minerals, fortified salt and vitamins, volition more often than not meet the nutritional needs of this group.

Grouping 2 - Bred replacement heifers and second calf heifers - Immature, growing animals do non compete effectively for feed with mature cows. Heifers require expert quality hay, silage or alternative feeds, or grain to meet their needs for growth and development. These animals are still growing and gaining body weight, in addition to developing the fetus. These animals may benefit from organic (chelated) or hydroxy trace mineral supplements, which have greater bioavailability, to support growth and reproduction.

Group three - Sparse, old cows - These cows volition need extra energy, particularly during winter months. These cattle may benefit from additional vitamin and mineral programs to avert deficiencies.

Group iv - Yearling steers, bulls - Steers and bulls will require different feeding programs depending on their size and if they are on a maintenance plan or are backgrounding or finishing.

If the ration is based on straw or low-quality hay, or if feed intake is limited, information technology is even more important to split the herd into unlike feeding groups to match the nutritional needs of each group. Use feed testing and ration balancing software like Cowbytes to make up one's mind the advisable ration and amounts of feed for each group.

Decision

Cattle crave free energy, poly peptide, water, vitamins and minerals in acceptable amounts for optimal diet. The requirements for these nutrients will vary depending upon the class, age, condition, and stage of production of the animal. Environmental factors will also influence fauna nutrition and nutrient levels both in the feed and h2o sources. Feed costs correspond the greatest expense associated with beef production. Nutrition is the almost of import gene for cow fertility, which is a main driver of profitability. Supplemental vitamin and mineral programs can improve livestock health, immune part, performance and fertility.

Each performance is unique; piece of work with a nutritionist to identify and correct nutritional deficiencies early, before herd wellness and profitability is compromised. Place groups of cattle that may require additional or customized feeding strategies. Feeding only depression-quality feedstuffs to relieve feed costs volition more often than not increase reproductive losses, unless offset by what is probable to be a more expensive supplementation program. A properly counterbalanced ration volition meliorate cattle functioning, productivity and ultimately profitability.

Definitions

Acid detergent fibre (ADF) - a chemic analysis that estimates the full fibre (including indigestible lignin) in the feed. A high ADF indicates reduced digestibility and likely lower voluntary feed intake.

Amino acids - nitrogen-containing molecules that are the building blocks used to create poly peptide in the body.

Available protein - the portion of crude poly peptide that tin be digested by the animal. It represents the proportion of full poly peptide after deducting the ADF-Due north fraction of a feed.

Carbohydrate - a source of dietary energy that includes starches, sugars, pectins, cellulose and hemicellulose. All carbohydrates comprise carbon, hydrogen and oxygen, and are usually divided into two types: structural (fibre from constitute wall) and non-structural (sugars and starches from plant cell contents).

Cellulose - a fibrous carbohydrate that is the main role of plant cell walls.

Chelated mineral - a chemical bond formed between an organic molecule and a mineral that increases mineral bioavailability to the creature and tin can reduce excretion of backlog minerals in manure.

Crude protein (CP) - an gauge of the total protein content of a feed adamant by analyzing the nitrogen content of the feed and multiplying the issue by 6.25. Crude protein includes true protein and not-poly peptide nitrogen sources such every bit ammonia, amino acids and nitrates.

Digestible energy (DE) - the apparent energy that is available to the animate being past digestion, measured every bit the deviation between gross energy content of a feed and the energy independent in the animal'southward feces.

Fat soluble vitamins - stored in the animal's fat reserves or liver, including A, D, Eastward, and One thousand.

Hemicellulose - a saccharide found in plant jail cell walls that is more complex in structure than sugars but less circuitous than cellulose.

International unit (IU) - a standard unit of potency of a biological amanuensis, such as a vitamin, hormone, vaccine, or antibiotic.

Neutral detergent fibre (NDF) - an insoluble fraction containing all institute prison cell wall components left after boiling a feed sample in a neutral detergent solution. A high NDF indicates lower digestibility and voluntary feed intake.

Non-protein nitrogen (NPN) - urea and ammonia are compounds that tin can be used by the microorganisms in the rumen to form true protein, that can then be converted to meat or milk past the animals. When feeding depression quality, depression protein feeds, urea tin can assist the ruminal leaner to create truthful protein.

Non-structural carbohydrate - comprised of sugar, starch and pectin, this is the not-NDF fraction of feedstuffs.

Rumen degradable protein (RDP) - the portion of dietary protein that is degraded in the rumen. It feeds the rumen bacteria, supplying microbial poly peptide.

Rumen undegraded protein (RUP) - the portion of dietary protein that escapes deposition by ruminal microorganisms and passes into the pocket-size intestine where information technology is digested and absorbed.

Structural carbohydrate - the fibrous, cell wall or back up construction of the plant, containing cellulose, hemicellulose and lignin.

H2o soluble vitamins - include the B circuitous vitamins and vitamin C. They are generally non supplemented to cattle afterward two months of age, due to the ability of rumen microbes to manufacture them in adequate amounts¹².

References

1. Hamilton, T. 2015. Basic Beef Cattle Nutrition. Ontario Ministry of Agriculture.
2. Meat and Livestock Australia Limited. 2006. Beef Cattle Nutrition.
3. Guyer, P.Q. 1976. Use of Energy Values in Ration Formulation. G76-321. University of Nebraska.
4. Parish, J.A. 2008. Protein in Beef Cattle Diets. The Beefiness Site.
5. Alberta Ministry of Agriculture. 2005. Water Requirements for Livestock.
6. Rasby, R.J., A.L. Berger, D.E. Bauer, and D.R. Brink. 2011. Minerals and Vitamins for Beef Cows. University of Nebraska.
7. McKinnon, J. 2017. More Questions on Mineral Diet. Canadian Cattlemen Magazine.
8. Drovers. 2011. When to Use Chelated Trace Minerals.
9. Bailey, East. 2017. Academy of Missouri Extension. Vitamins for Beef Cattle.
10. Hall, J.B. 2009. Nutrition and Feeding of the Cow-Calf Herd:Production Cycle Diet and Nutrient Requirements of Cows, Meaning Heifers and Bulls. Virginia Cooperative Extension, Virginia Tech, Virginia State University.
11.   The Cattle Site. 2013. The Annual Product Cycle. world wide web.thecattlesite.com.
12. Ontario Ministry building of Agriculture, Nutrient and Rural Affairs. 2012. Definitions of Feed Manufacturing and Livestock Nutrition Terms.

This topic was concluding revised on March 23, 2022 at 7:53 AM.

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Source: https://www.beefresearch.ca/research-topic.cfm/beef-cattle-nutrition-107

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