- Animals: bovine
- Animal Production: animal protection and health, feed formulation, feed rations
- Education and Training: demonstration, extension, participatory research
- Farm Business Management: agricultural finance
Cattle in feedlots are typically fed total mixed ration (TMR). However, feeding animals a TMR may lead to inefficiencies in feed conversion, reduced gains and increased illness. Providing animals a choice of foods can increase intake, improve feed efficiency and decrease costs compared to feeding a TMR. For example, dairy cows offered strips of clover and grass produced 11% more milk, and sheep ate 25% more forage than those grazing a mixture of grass and clover. Feed costs were reduced by 19% in cattle fed a choice of grains, hay and silage rather than a TMR of those ingredients. Offering sheep and goats a dietary choice resulted in increased average daily gain (ADG), improved feed efficiency and reduced illness. Dairy goats given a choice of foods increased intake of dry matter, energy and protein, increased milk yield and decreased weight loss compared to goats fed a TMR. Animals offered a choice of foods avoid over-ingesting nitrogen (N), which reduces concentrations of N in animal waste. Dairy cows offered a choice of two rations selected a diet of 18% crude protein (CP) but produced the same amount of milk as cows fed a 19.7% CP diet. Sheep also select diets that meet their protein needs and avoid eating too much protein when given a choice of foods.
Offering livestock a choice of foods likely allows them to select a diet that meets their individual needs. Lambs selected for uniformity in age, sex and breed still vary in their food preferences. Genetic variation among individuals can cause physiological (e.g., rates of nutrient uptake) and morphological (e.g., size of digestive tract) differences that may affect intake and preference. Variations in food intake and growth rate of cattle are often higher within a breed than between breeds. The variations in food intake and growth rate of cattle are often higher within a breed than between breeds. Differences in fatty acid synthesis, absorption and breakdown result in varying degrees of fatness of livestock. Animals with larger hearts and kidneys have higher metabolic rates and higher intakes.
Level of production also affects nutrient requirements. Lastly, choice provides animals with variety.
Animals prefer variety to monotony. Herbivores often select a variety of foods that vary in nutrients, even though one food seems to best meet their needs.
The current project will test the hypothesis that allowing cattle to voluntarily select feeds that differ in nutritional value will improve performance. To test this hypothesis, growing heifer calves will be assigned to two groups and fed in a GrowSafe feed system that measures individual animal intake via RFID ear tags. Voluntary intake will be monitored for Group 1 (Controls; n = 16) fed a conventional TMR formulated from grass hay, corn and alfalfa to meet NRC requirements for targeted gains of 1.5 to 2.0 lb/day. Voluntary intake of the same individual feeds (grass hay, corn and alfalfa) will be monitored in Group 2 (Feed-select, n = 16) by placing the three feeds in separate bunks. Heifers will be evaluated for weight gain and individual feed intake during the test period. Daily gain, feed efficiency and residual feed intake (RFI) will be individually calculated to determine if voluntary diet selection improves performance and feed conversion. Profitability of the two feeding systems will be compared by contrasting feed costs, including costs associated with diet formulation, equipment, labor, gains achieved, feed efficiencies and net income received. Finally, we have a comprehensive outreach effort planned. Our outreach is likely to be very effective due to the fact our producers are influential individuals in the state beef industry, as well as their local communities.
Project objectives from proposal:
1. To determine if ADG, feed efficiency and RFI of cattle fed a total mixed ration differs from cattle allowed to self-select their dietary ingredients (Note: RFI is the difference between an animal’s actual and predicted feed intake based on equations for maintenance and growth. RFI is used to rank animals from most to least efficient. A negative RFI means animals are more efficient than average, and those with a positive RFI are less efficient.)
2. To compare the profitability of cattle fed TMR to cattle allowed to self-select their dietary ingredients.
3. In collaboration with producers participating in the project, create “producer-friendly” web and print resources to help relay the impacts of the project to other livestock producers.