County Agent Update

Nutrition and Feeding of Beef Cattle

Cattle are ruminants, the digestive system of cattle includes a large fluid filled rumen containing a large population of microbes. Microbes have the ability to break down fibrous components of roughages and initiate feed digestion. As feed passes from rumen to smaller stomach structures, the body absorbs the water and the animal’s digestive enzymes further break down feed for nutrient absorption. As calories define the energy in food we eat, and what is used/required for activity and growth; in cow rations, energy is often expressed as TDN (Total Digestible Nutrients). This may be expressed on a percentage basis of feed or in pounds per day. Cattle obtain energy from digestible fiber, starch and to a lesser extent sugars and fats. Protein is required both for the rumen microbial population and the animal. The animals need protein for growth, lactation and reproduction is met by a combination of microbial protein and protein which bypasses rumen breakdown and is digested and absorbed further in the GIT (gastrointestinal tract). Supplying the need for rumen nitrogen is met by feed sources which are easily degraded in the rumen. Microbial activity is further associated with greater fiber breakdown and roughage intake.

In addition to energy and protein, a variety of minerals and vitamins are required for physiological functions. Calcium and phosphorus are needed in the greatest quantities with varying concentrations among commonly fed feeds. While other minerals as copper, zinc, selenium are needed in much smaller quantities, they are often deficient on feed produced in soils in the region and provided in supplements. Most vitamins are often provided in high quality, fresh green forages, but are also supplemented to insure against deficiency with mature, weathered forages, grains and grain by products.

Nutrient needs are greatest shortly after calving in early lactation and returning to estrus for rebreeding. Conversely nutritional needs are lowest following weaning while cows are dry and in mid-gestation. It is an opportunity to utilize lower value cost feed alternatives and/or to cheaply put weight on and recondition cattle. Young developing cows, two and three year olds, require higher quality feeds to meet their added requirement for growth. Cows selected and capable of high milk production will have increased nutrient needs for both maintenance and milk production. While larger cows do not need feeds higher in quality or nutrients expressed as a percentage, they will have greater intakes and a need for additional quantities of protein and TDN. In the north, cold stress also impacts energy needs. Cold stimulates intake and if given the opportunity a cow can eat more to meet added need to about -10 degrees F. Extremes beyond this due to wind chill or ambient temperatures require feeding higher energy feed rather than increasing feed provided. The impact of cold on cow energy needs is less for cows in good flesh and body condition. This information is from John Dhuyvetter, Area Livestock Specialist at the North Central Research Extension Center.

NDSU Extension Service Williams County would like to wish you all Happy Holidays. Stay warm and safe.