Feeding Practices for Commercial and Research Swine

By: Gary L. Brubaker, PhD, Swine Physiologist

Research swine being fedThe feeding of swine for commercial production and for research models is a high level science based upon a long history of accumulated agricultural and government research. Standards may be found in the National Research Council’s recommendations on the Nutrient Requirements of Swine, Ninth Revised Edition, 1988, National Academic Press.

Swine are monogastric animals (having a simple stomach very similar to humans) that require a high quality source of proteins and energy as well as the proper amounts and ratios of micronutrients (vitamins and minerals).

Swine are fed rations according to their physiological state


adult animals held in a non-production condition


pregnant sows or gilts (weight range 250-550 lbs.)


sows or gilts nursing litters of piglets


dry feed piglet supplements during lactation (17-25 lbs.)


young pigs in the very early growth stages (25-40 lbs.)


the early stages of growth (40-160 lbs.)


last stages of growth (160 – 260 lbs.)

Performance is related to both the quality of the diet as well as the amount consumed on a daily basis. Weaning, growing and finishing pigs are fed ad libitum because of their high energy and nutrient requirements whereas adults are fed specific daily amounts according to body weight and age.

Maintenance Animals:

Adult boars, sows and gilts are fed rations to maintain them in healthy physiological state before and after breeding, lactating, gestation and breeding. This is an equilibrium state were the adults are maintained in homeostasis and body condition and body weight are maintained.

Gestating Gilts and Sows:

The NRC recommends feeding 4-5 lbs. per day of a corn soybean based diet with an energy level of 3,300 kcal of ME/kg. This will meet the energy needs of the sow or gilt for maintenance as well as supplying energy for fetal growth and development.  This diet should contain 16% CP (crude protein).

Lactating Gilts and Sows:

The NRC estimates that lactating gilts and sows nursing 11-12 piglets that gain 240g/day during a 21-day lactation require 13-14 lbs. of feed per day. If feed intake is too low, sows will lose excessive weight during lactation which will affect the ability of the sow to enter a post weaning heat for the next breeding cycle. Also at this time diets high in protein (16% CP) and amino acids should be fed to prolific sows to maximize milk production and prevent excessive weight loss of the sow.

Growing-Finishing Pigs:

All weight classes of pigs in the growing-finishing phases of production require diets containing 3,300 kcal of ME/kg as outlined by the NRC and should be fed ad libitum. Crude protein levels range from 16% for growers to 14% for finishing pigs. Environmental conditions must be ideal to maximize feed conversion, growth and vigor. Adequate temperature, ventilation and floor space requirements must be met within the facility

Major Feed Ingredients:

Swine are fed grain-based rations with ground corn as the energy source and soybean meal as the high quality protein source.  Mineral and vitamin premixes are then added to this to meet the nutrient requirements and energy for the six types of rations.  At the ABI swine production units, the ground corn and soybean meal is purchased and stored in large grain bins on the farm.  Commercially prepared vitamin and mineral premixes are bought and stored in smaller bins. Each type of ration is formulated by auguring specific amounts of each ingredient into a mixer to formulate each of the six types of rations. These are called a TMR, total mixed rations.


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