Final Report for OW12-020
Cattle in feedlots are typically fed a total mixed ration (TMR). However, feeding a TMR may lead to lower feed efficiency, reduced gains, and increased stress when compared to offering cattle a choice of feeds in the TMR. We determined how cattle offered a choice of foods or a mixed ration of those same foods would affect the performance and profitability of cattle. In year 1, heifers were fed a mixed ration (70% corn, 19.2% alfalfa pellets, and 10.8% haylage) or free choice of the three foods. Cattle given a choice of foods ate 69% corn, 26.9%, alfalfa pellets, and 4.1% haylage. No differences were detected in intake, gain, feed efficiency, or cost of gain. In year 2, heifers were fed a mixed ration (60% corn and 40% chopped alfalfa hay) or a choice of corn and hay. Heifers offered a choice of feeds ate 74.3% corn and 25.7% alfalfa hay. Cattle given a choice of foods ate less feed but gained at the same rate as those fed the mixed ration. Feed to gain ratio and total intake were lower for choice than mixed. Cost per pound of gain was similar for the two groups of heifers. Offering animals a choice of feeds may be a viable way for producers to finish their cattle because offering a choice of feeds compared to a mixed ration: 1) eliminates the need to mix feed and for a nutritionist to balance the ration; 2) animals of different sizes and ages can be fed together; 3) gives producers flexibility when marketing their animals; 4) may improve feed efficiency and cost of gain while decreasing stress and illness.
Finishing cattle prior to slaughter typically entails feeding total mixed rations (TMR) nutritionally balanced for a group of cattle. Group feeding a TMR is thought to be the best method to feed animals concentrate rations. Under a TMR feeding system the ration is balanced for the nutritional needs of the average animal. Unfortunately, this practice doesn’t consider importance of individual variation in need for nutrients. Past research shows that as many as half of the animals within a group may have different nutritional needs or tolerances when compared to the “average” animal (Provenza et al., 1996; Villalba and Provenza, 1996; Scott and Provenza, 1999). Thus, feeding a TMR may negatively affect the productivity of some animals fed a TMR formulated to meet the needs of the “average” animal.
Offering livestock a choice of foods likely allows them to select a diet that meets their individual needs. Choice also 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. Lastly, offering animals a choice of foods reduces their stress.
Numerous studies have shown that providing animals a choice of foods can increase intake, improve feed efficiency, and decrease costs compared to feeding a TMR. However, only one study on offering cattle feed choice has been conducted in the U.S. Most studies on feed choice have been conducted on sheep or goats outside the U.S.
This project tested if allowing cattle to voluntarily select feeds that differ in nutritional value will improve livestock performance. Growing heifers were assigned to two groups and fed a 1) TMR or 2) choice of feeds. They were fed in a GrowSafe feed system that measures individual animal intake via RFID ear tags. Heifers were to be evaluated for weight gain and individual feed intake during the test period. Daily gain, feed efficiency, and residual feed intake (RFI) were to be individually calculated to determine if feeding method will improve performance and feed conversion. Profitability of the two feeding systems were to be compared by contrasting feed costs, including costs associated with diet formulation, equipment, labor, gains achieved, feed efficiencies, and net income received.
- 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.
- To compare the profitability of cattle fed TMR to cattle allowed to self-select their dietary ingredients.
- 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.
Trial 1: Summer-Fall 2013
In 2013, we purchased 36 yearling heifers from the Torrington Livestock Auction. Heifers were trucked to the James C. Hageman Sustainable Agriculture Research and Extension Center (SAREC), Lingle, WY on May 21, 2013. Upon arrival they were fed a growing ration for 30 days.
Control heifers were fed a conventional total mixed ration composed of grass haylage, corn, and alfalfa pellets formulated to meet National Research Council (NRC) requirements. Choice heifers were fed the same feedstuffs separately to allow them to select their dietary ingredients.
Heifers were blocked by weight and randomly assigned to one of two groups: Control or Choice (n = 9/group). One group (mixed) was fed a mixed ration containing 60% whole corn, 25% haylage, and 15% alfalfa pellets. The other group was fed the same ingredients used in the mixed ration, but feeds were placed in separate feeders and animals were allowed to select their own diet (choice). The nutritional analyses of feeds used in the trial are in Table 1.
The feeding trial had two treatments with two replications and nine heifers per replication.
The GrowSafe system used to feed heifers automatically records feed intake each time an animal eats. Intake was recorded from July 15 to September 26, 2013. Heifers were weighed three times during the trial. The cost of feeds on a dry matter basis (DMB) was $0.13/lb for corn, $0.24/lb for alfalfa pellets, and $0.16/lb for haylage. Thus, roughages were more expensive than corn.
After September 26, 2013, heifers were removed from the GrowSafe, housed in two pens, and fed using the same method (mixed or choice) as in the feeding trial. On December 19, 2013, they were weighed and sold for slaughter.
Trial 2: Fall-Early Winter 2104
During 2014, three local producers and University of Wyoming provided eight heifers each (32 heifers total) to participate in the second feeding trial. Heifers were blocked by weight and owner, and randomly assigned to one of two groups; Control or Self-select (n = 16/tretment).
Control heifers were fed a conventional total mixed ration composed of ground alfalfa hay and corn to meet National Research Council (NRC) requirements. Self-select heifers were fed chopped alfalfa hay and corn separately to allow them to select their own diet.
The trial took place at the University of Wyoming Sustainable Agriculture Research and Extension Center in Lingle, WY. Heifers arrived at the facility on October 13-15, 2014. Each treatment group was divided in half with eight heifers/pen (two reps/treatment and eight heifer/rep). Heifers were weighed on October 20 and 21, 2014 and the weights from the two days were averaged to calculate their weight at the beginning of the trial. Heifers were accustomed to the feeding system for and the feeds for eight days from October 20 through October 27, 2014. The feeding trial was conducted for 70 days from October 28, 2014 to January 6, 2015.
Heifers were fed automatically using the GrowSafe system, which automatically records feed intake each time an animal eats. Intake was recorded from October 28, 2014 to January 6, 2015. Heifers were weighed three times during the trial. Costs of feeds as fed were $0.17/lb for corn and $0.07/lb for alfalfa hay. The mixed diet was 60% corn and 40% chopped alfalfa hay.
Average daily gain (ADG), feed efficiency and feed costs per pound of gain were also calculated for each heifer.
Trial 1: Summer-Fall 2013
In the 2013 trial, no differences were detected between treatments for feed intake, body weight, average daily gain, feed efficiency, or cost of gain (Table 2). Quality and yield grades were similar between treatments (data not shown).
Heifers offered choice or a mixed ration had similar performance and cost of gain. Even though heifers had free access to corn, they did not suffer from bloat or acidosis.
Average food preference on a DMB for choice group was 69% corn, 26.9% alfalfa pellets, and 4.1% haylage. Preference on a DMB for the mixed diet was 70% corn, 19.2% alfalfa pellets, and 10.8% haylage. For heifers offered a choice of foods, intake of AP varied from 13.8 to 40.7% for AP, 56.5 to 81% for corn, and haylage was1.6 to 6.4% of the diet. Table 3 shows the variation in preference among heifers offered a choice of foods. Intake of corn was similar between the two treatments. Heifers in the choice group preferred alfalfa pellets to haylage probably because pellets have higher rates of intake than haylage and perhaps because heifers were not familiar with the haylage.
Quality and yield grades were similar between treatments Table 4.
Trial 2: Fall-Early Winter 2104
In Trial 2, local producers and University of Wyoming provided replacement heifers for this trial. However, as stated in the original proposal the objective of this study was to compare two feeding systems (mixed versus choice) for finishing livestock
It is unclear why the study was conducted with replacement heifers. As a consequence, data and results are not comparable between years.
Results are presented in Table 1. The feed to gain ration and total feed intake was lower for choice animals compare to mixed probably because heifers fed the mixed diet ate more hay and less corn than choice animals. Despite the above differences, cost of gain was the same for both groups.
Average food preference on a DMB for choice group was 74.3 corn and 25.7% chopped alfalfa hay. Preference on a DMB for the mixed diet was 60% corn and 40% chopped alfalfa hay. For heifers offered a choice of foods, intake of hay varied from 14.9 to 34.5% and corn intake varied from 65.5 to 85.1% for corn.
Education and Outreach
Journal of the NACAA
Journal of Animal Science
Education and Outreach Outcomes
Areas needing additional study
Based on a preliminary analysis of behavioral data from this study, we are not certain if the Safe system really provided heifers a free choice of feeds. Choice heifers in both studies were observed guarding the feeders so that when other heifers were ready to eat they may have been unable to eat, thus limiting intake. We did not plan to analyze the behavioral data from the study, but it will be analyzed at a later date and added to this report.