Cows, like other ruminants, naturally graze on grasses and other vegetation for sustenance. However, when dairy cows produce high yields of milk, their diet must be more nutrient-dense to support their production.
To meet this dietary need, farmers and nutritionists blend protein (amino acids), fat, minerals, vitamins, and feed additives together into a total mixed ration or TMR that is then given to cows as part of their TMR meal.
Contents
Grass
Grass is green due to chlorophyll, a pigment that absorbs energy from the sun. Furthermore, grass absorbs water and nutrients from the soil in order to thrive.
Cows prefer grass to humans because it contains all of their essential chemical elements for making milk: carbon, hydrogen, oxygen, nitrogen, phosphorus, sulfur and calcium.
Dairy cows need to consume between 2.5% and 3% of their body weight in grass each day for a healthy and productive lifestyle. Furthermore, they can obtain plenty of essential nutrients from other crops like corn, barley, clover, alfalfa hay and oats.
Dairy producers are increasingly adding grass to their cow diets to reduce feed costs and enhance production, health and performance. Dairy farmers are beginning to cultivate grasses as a source of high quality forage in their rations; they can harvest various grasses such as ryegrass or red clover for adding into hay or silage mixes. Furthermore, they may use manure or slurry fertilizer on the grass stands.
Grain
Grain is an integral component of dairy cows’ diets. While it accounts for less than one-quarter of their total intake, this includes specially grown grains like corn kernels as well as byproducts from the food or beverage industry.
Dairy farmers collaborate with a nutritionist to formulate and ration the diet for their herd. The majority of their animal’s food comes from forage (hay or silage; Figure 1).
Cows grow older and produce more milk when fed a total mixed ration – commonly referred to by farmers as “hay and grain”. This combination of feeds leads to increased milk production as the cows age and begin eating grain mixed with other feeds such as hay.
This total ration contains protein, carbohydrates and essential minerals and vitamins as recommended by a trained nutritionist. Most of the protein comes from high-quality ruminally and post-ruminally digestible sources; carbohydrates come from barley, corn, oats, wheat and molasses while fat comes from soybean meal, distillers grains and canola oil.
Byproducts
Milk cows recycle by-products from major and specialty agricultural crops that would not make it into human food products. Dairy farmers use byproducts like cottonseed, distillers grain and brewers grain as feed for their herds while helping reduce landfill waste.
These byproducts provide essential nutrition to dairy cows and help control dairy feeding costs. Furthermore, they free up Central Valley crop land and water for other uses while decreasing greenhouse gas emissions.
Minerals & Vitamins
Minerals and vitamins are an essential part of a dairy cow’s diet. Not only do they aid in growth and milk production, but they also improve their overall wellbeing.
Calcium, phosphorus, potassium, magnesium and sodium are the essential minerals for milk cows. Other essential minerals like iron, copper, zinc, manganese and selenium also play a role.
When making a grain mix or total mixed ration (TMR), it is essential that all essential nutrients, including minerals and vitamins, are included at the proper amounts. Doing this helps guarantee that heifers, dry cows and milking cows receive enough of each nutrient for optimal health and performance.
Minerals must be consumed in both gram quantities (macrominerals) and parts per million (ppm). They can be acquired either through trace mineral premixes or added to grain mixes or total mineral replacement (TMR) at the correct rates.
