Most dairy heifers in the pre-weaning phase are fed milk replacer rather than whole milk. Among the management decisions for feeding milk replacer are convenience, consistency, biosecurity and economics.
Milk replacers vary in their protein and fat ratios and also in the type and quality of the proteins and fats used. Different additives and medications can be included in the milk-replacer formula to fit the specific needs and goals of each calf-raising operation. That makes milk replacers a valuable and customizable feedstuff.
- Milk proteins are typically recommended in milk replacers because they’re more digestible for calves than non-milk protein sources. Offering a desirable amino-acid profile, sources of milk proteins include whey, whey protein concentrate, whey solubles, de-lactosed whey, skim milk and casein. Whey proteins are the most prominent source of protein for milk replacers.
- Animal-plasma protein is an exception to the rule as far as non-milk proteins go. It’s an excellent source of nutrition for calves and delivers additional benefits in the gastrointestinal tract. Animal plasma carries antibodies in the form of immunoglobulin, which provides a consistent source of protection against pathogens and bacteria in the calf’s small intestine.
- Other non-milk proteins include hydrolyzed wheat-gluten protein and soy protein, which can serve as economic alternatives to milk protein. While non-milk proteins can support calf growth and performance, their overall digestibility is lower compared to milk and animal-plasma proteins. Their amino-acid profile also is different and needs to be balanced to meet the needs of the calf.
- Fats provide a concentrated energy source in milk replacers and include both lard and tallow. Since fat isn’t water soluble, milk-replacer makers typically combine fat with proteins and emulsifiers to homogenize the mix. That creates small, dispersed particles that stay in suspension in water.
- Oils provide a concentrated energy source and include vegetable oils, such as palm and coconut. Oils also are insoluble in water, which means they undergo the same emulsifying process. Vegetable oils are highly digestible energy sources and provide health benefits to the calf thanks to their antimicrobial properties.
- Carbohydrates also can supply energy in milk replacers. Lactose is the major carbohydrate found in whey and whey-protein concentrate. It supplies half of the energy value of fat. A typical milk replacer contains about 45 percent lactose, making it a major energy source.
- Vitamin A is necessary for normal and low-light vision. It helps maintain skeletal tissue and epithelial tissue, and is important for normal growth and development.
- Vitamin D is required for calcium metabolism and bone and tooth formation.
- Vitamin E acts as an antioxidant and is involved in the maintenance of cellular membranes, metabolism, immunity and reproductive function.
- Vitamin B12 affects energy and protein metabolism and is used by enzymes.
- Thiamin plays a role in energy metabolism and helps support nerve and brain function.
- Vitamin C acts as an antioxidant. It’s important for tissue repair and connective-tissue synthesis and is classified as an essential nutrient for calves three weeks of age or younger.
- Biotin acts as a cofactor for many enzymes. It’s involved in carbon-dioxide fixation and decarboxylation and supports hoof health.
- Choline is involved in the transmission of nerve impulses and fat metabolism.
- Folic acid is used in amino-acid synthesis. It improves red-blood cell formation and the oxygen-carrying capacity of blood. It’s necessary for the synthesis of nucleic acids.
- Pyridoxine plays a role in the enzyme systems involved with protein metabolism.
- Vitamin K is required for protein synthesis and blood clotting.
- Riboflavin is a constituent of several enzyme systems associated with metabolism.
- Niacin is essential for carbohydrate, lipid and amino-acid metabolism.
- Calcium is essential for formation of skeletal tissues and transmission of nervous-tissue impulses. It's also essential for excitation of skeletal and cardiac-muscle contraction, blood clotting and enzymatic activity.
- Chlorine maintains the acid-base balance. It’s a component of gastric secretions and is essential for the transport of carbon dioxide and oxygen.
- Cobalt is an essential component of vitamin B12, growth and energy status.
- Copper is crucial for many enzymes and is important for bone, collagen and elastin formation.
- Iodine is an essential component of hemoglobin and oxygen transport.
- Iron primarily functions as a component in hemoglobin and myoglobin.
- Magnesium is a major intracellular cation that’s a necessary cofactor for enzymatic reactions vital to every major metabolic pathway.
- Manganese is a component of enzyme systems and is essential for normal bone formation.
- Phosphorous is intimately involved in the acid-base buffer systems of blood and other bodily fluids. It’s also involved in almost all energy transactions in the body.
- Potassium is involved in osmotic pressure and acid-base regulation, water balance, nerve-impulse transmission, muscle contraction and oxygen and carbon-dioxide transport. It also serves as an activator in many enzymatic reactions.
- Selenium is involved in protein synthesis, muscle development, immunity and growth.
- Sulfur is a critical component of several amino acids, cartilage and B vitamins.
- Zinc plays an important role in energy and protein metabolism and gene expression. It also supports the immune system.
- Organic trace minerals offer improved mineral absorption and bioavailability. That can improve feed efficiency, growth and intake while also decreasing trace-mineral excretion in manure.
- Decoquinate is a coccidiostat designed to stop the growth of coccidia by inhibiting mitochondrial activity inside the cocci cell. Total oocyst reduction with decoquinate is about 98 percent.
- Lasalocid is a coccidiostat designed to kill coccidia. It functions as an ionophore that moves potassium, sodium, calcium and magnesium into the cocci cell, causing it to swell and burst. Total oocyst reduction with lasalocid is about 96 percent.
- Oxytetracycline and neomycin sulfate is an antibiotic combination that provides broad-spectrum antibacterial activity for treating and-or controlling bacterial enteritis and bacterial pneumonia. A veterinary feed directive is needed to purchase and use the medication.
- Mannan oligosaccharides enhance feed efficiency, immune-system development and gut health. That helps to normalize gut microflora, stimulate natural defenses, and reinforce digestive-system function.
- Direct-fed microbials are live organisms that provide health benefits to the calf by stimulating a healthy gut environment and preventing growth of undesirable pathogens.
- Essential oils are plant extracts that contain an array of antimicrobial activity. Certain essential oils have been shown to stimulate appetite, resulting in improved feed intake and growth.
- Essential fatty acids can support the calf’s immune system and promote growth and feed efficiency.
- Diflubenzuron is a larvicide product that prevents the development of house flies, stable flies, face flies and horn flies in manure of treated calves.
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Ellan Dufour is a dairy-research nutritionist at Hubbard Feeds