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GrowSafe research project first of its kind

by Wyoming Livestock Roundup

Laramie – University of Wyoming PhD candidate Rebecca Cockrum began looking at feed efficiency in sheep using residual feed intake (RFI) a year and a half ago with the intent of helping producers cut costs by selecting high efficiency animals for their flock.

“Producers have between 60 and 75 percent of their inputs attributed to feed,” says Cockrum. “If we can find a way to help them select for more efficient animals, that will be able to save producers money in the end.”

Working in conjunction with Wyoming producers, Bryce Reece and the Wyoming Woolgrowers Association and the Rambouillet Association, Cockrum has begun gather feed intake data using a specially designed GrowSafe system.    

The GrowSafe system used in Cockrum’s trial is a one-of-a-kind model constructed for use in sheep, rather than simply a modified cattle GrowSafe system.

“They have transponders in their ear, and every time an animal goes in, it takes measurements of how much feed is being consumed, how long they are in there and how many times per day they go in,” says Cockrum. “We also get a lot of behavior information.”

Using the data reported from the GrowSafe systems, Cockrum is able to determine whether animals are efficient or not.

“We generate an expected intake and look at how much the animals are actually consuming. From there, we can determine if an animal is more or less efficient,” explains Cockrum.

“If they are consuming more than what is expected for their given body weight, that is considered a less efficient animal.”

Cockrum’s preliminary data shows that the top 15 percent of rams studied consumed 22 percent less feed than the lowest 15 percent. RFI is calculated as the difference between actual and predicted feed intake. A higher RFI means the animal is consuming more food than predicted for their body weight and is less efficient.

Using RFI data rather than a simple gain to feed ratio provides an alternative that can be more accurate.

After collecting feed data, Cockrum will begin looking at blood samples she has taken from each animal to attempt to identify a genetic component for feed efficiency.

“I will probably have around 400 blood samples. I am going to identify those animals that are more or less efficient and isolate the DNA from blood samples,” says Cockrum. “We have been collaborating with a group in New Zealand to hopefully identify some markers that are associated with efficiency.”

AgResearch in New Zealand is also collecting samples and will likely have more than 1000 blood samples that Cockrum will contribute her data to.

“We are collaborating with New Zealand to be able to identify these markers accurately. We are looking at a variety of breeds and different environments with a large number of samples to increase accuracy,” says Cockrum.

“Hopefully one day, we will be able to see a producer be able to take a blood sample and test it on a chip to tell if their animals are efficient or not at weaning,” explains Cockrum.

“That is the ultimate goal.”

Cockrum also aims to identify if this trait is an ideal trait to select for. Research projects to address each of those components are being simultaneously carried out.

“For this to be an appropriate trait for producers to select on, we need to make sure it is independent of any carcass characteristics and growth traits, as well as any reproductive traits,” says Cockrum.

Though Cockrum started this project just over a year ago, she has data on the animals going back almost three years to aid her research.

“By the time I am done with my PhD, we will hopefully have some markers identified,” says Cockrum. “From there, we will have to go through several validation tests to make sure the markers we have selected are indeed going to work.”

Cockrum says there are some economic analyses that need to be conducted to see if the purchase of such a chip will be beneficial to producers.

“We need to see if it is really going to be worth it to producers to be able to purchase a chip like this and see how many markers they are willing to pay for,” says Cockrum. “I’m hoping to get in touch with several producers and collaborate with them to get economic figures.”
Cockrum’s project covers a variety of aspects of the sheep industry and aims to help producers in ways not seen in other industries.

“The sheep industry is on the cutting edge of technology. Even the beef and swine industries don’t have this kind of information yet,” says Cockrum. “This is a very integrated project.”

Cockrum is the primary student working on the project under the direction of Kristi Cammack. She is also working with Scott Lake and Bob Stobart at the University of Wyoming and Laramie Research and Extension Center.

Saige Albert is assistant editor of the Wyoming Livestock Roundup and can be reached at

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