Dairy cows are ruminants, meaning they require a diet with carbohydrates, protein, fat and minerals for milk production and optimal animal health. This food should be specifically tailored to meet their dietary needs.
Dairy cows primarily feed on forages, which provide essential nutrition. This includes both grasses and legumes.
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Protein
Protein is a vital nutrient for dairy cows, as it aids in growth, lactation and reproduction. Furthermore, protein plays an essential role in the production of milk; thus, dairy producers must find ways to meet their protein needs without increasing costs.
Protein is an essential element of milk cow feed, not only providing energy but also protein to meet their high protein needs during lactation. This ensures their bodies can support the strain that comes with such high milk production rates.
Protein in feed is typically measured as crude protein (CP). This value can be calculated by multiplying the nitrogen (N) content of the feed by 6.25.
Fat
Fat is an essential nutrient for milk cows and is affected by several factors both within and outside of the cow, such as genetics and breed differences, stage of lactation, milking interval, seasonal variation, disease incidence and nutrition.
Dairy producers often prioritize maximising milk fat and protein content. Maintaining normal milk fat tests is an important factor in current milk pricing formulas, as well as a sign of good rumen and cow health.
Low dietary fiber, high non-fiber carbohydrates (starchy concentrates), low forage levels and small panicle length may increase milk protein percent by 0.2 to 0.3 units; however, these practices should not be employed since they cause acidosis, lameness and feed intake issues in cows as well as their rumen.
Carbohydrates
Carbohydrates are an integral part of lactating dairy cattle and growing heifers’ diets, accounting for up to 70% of their dry matter content. Fermented carbohydrates in the rumen provide energy for growth, maintenance and milk production by microorganisms in the rumen.
Carbohydrates can be divided into two categories: structural (cellulose and hemicellulose) and non-structural (starch and soluble sugars). Both sources contain individual sugar units or chains joined together by chemical bonds to form a complex structure.
Cellulose and starch are more difficult to digest than soluble sugars and require special enzymes in the rumen to be broken down. Feeding too much starch can have adverse effects on neutral detergent fibre concentration and digestibility, ruminal fermentation performance, overall health and production efficiency.
Minerals
Minerals are essential elements in providing milk cows with the optimal feed. They participate in numerous metabolic pathways within a dairy cow’s body, and even small mineral deficiencies can have an adverse effect on herd production performance.
Calcium and phosphorus are two essential macrominerals for growing cattle, as they aid in bone formation and maintenance.
They play an essential role in energy metabolism and cell formation, as well as DNA replication. Unfortunately, a shortage of calcium or phosphorus can lead to brittle bones, reduced weight gain, and poor reproductive efficiency in cows.
Vitamins
Vitamins are organic compounds essential for the metabolism of proteins, fats and carbohydrates. Normally produced in sufficient amounts by rumen microbes, some vitamins must be supplemented for specific uses.
Water-soluble vitamins like Vitamin A, D and E are commonly included in dairy cattle’s feed to meet their requirements. These essential nutrients support a healthy cow’s immunity system, energy production and cell integrity.
Vitamin D deficiencies are frequently linked to mastitis and other illnesses, so it’s important to regularly screen for them. Serum concentrations of 25-hydroxycholecalciferol can be used as an indicator for vitamin D status; adequate levels are 20-50 ng/mL while deficiency occurs at less than 5 ng/mL. Dry cows may require supplementation with 4,000 IU/d during the close-up dry period and 2,000 IU/d during early lactation.
