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New Mexico State University

New Mexico State University

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NMSU breeding project works to increase growth of sheep, maintain high-quality wool

CORONA, N.M. - A breeding project at the Corona Range and Livestock Research Center aims to generate meatier sheep, while maintaining the high quality of wool expected of New Mexico sheep.

Tim Ross checks his notes before starting the process of separating the sheep into pens as part of a crossbreeding research project at the Corona Range and Livestock Research Center. Ross is the head of the Animal and Range Sciences Department at New Mexico State University. He is also the lead researcher in the Corona project. (NMSU photo by Audry Olmsted)

"Producers are always out there looking for something that's going to be able to give them that edge on meat production," said Tim Ross, head of the Animal and Range Sciences Department at New Mexico State University, who is leading the project.

For the past three years, researchers in Corona have been artificially inseminating the NMSU Western whiteface ewes with South African Meat Merino (SAMM) rams, in an effort to help producers keep that edge.

"New Mexico wool has a reputation for being long, so we didn't want to compromise the wool clip while trying to get the growth," Ross said in explaining why they chose to use the SAMM. "Our idea now is to look at this as a crossbreed program. Can we bring the SAMM in, cross it onto our New Mexico Rambouillet-base type flock and generate the growth and increase in lambs, but yet maintain the wool quality?"

The SAMM was originally the German Mutton Merino, imported to South Africa in 1932. It became a dual-purpose breed, noted for its heavy muscle and acceptable wool quality.

At the start of the project, researchers artificially inseminated selected ewes, along with a control group. After the ewes had lambed, the lambs were identified with their dams and individually ear tagged. Their birth weights and genders were also recorded. When the lambs were weaned in October 2006, the cross SAMMs and the control group were both taken to the main campus and were housed and fed together. In January 2007, they were sheared and the wool samples were collected and sent to Texas AgriLife Research Center in San Angelo for analysis.

The yearling weights were recorded in May 2007.

The data showed that the SAMM cross lambs were four percent heavier at weaning and 16 percent heavier as yearlings. SAMM cross fleeces were 20 percent heavier, five percent lower in yield and were similar in length.

The average fiber diameter was greater for SAMM cross sheep than the control rams.

"Our hypothesis is that we can increase the pounds of lamb weaned by 10 to 15 percent without compromising wool clip with the SAMM as a cross," Ross said. This, he added, could mean a 10 to 15 percent increase in income for producers, helping to maintain the reputation wool clips have in New Mexico.

At the start of the project, the researchers artificially inseminated 60 ewes. In the most recent third cycle, they inseminated 80 ewes.

Although tentative conclusions show that the SAMM cross sheep offer a viable alternative for New Mexico sheep producers, and that the crossbreed is producing heavier lambs with minimal impact on the length of the wool, or its weight and diameter, Ross said they are hesitant to recommend the crossbreed to the sheep industry at this point.

"We don't know enough yet about the impact that the SAMM is going to have on the wool. We should have a much better idea with this next lamb crop," he said. The next lamb crop will be in May.

Ross said this research project, funded between the Corona center and NMSU's Agricultural Experiment Station, was completely producer driven, born from a request by ranchers to see if a sheep could be bred that had thicker muscle and heavier weaning weights that did not compromise wool quality.

The Corona research center was chosen for its central location in the state.

"It really hit a lot of the different ecological types of areas that a lot of our ranchers would be in and it was in traditional sheep country," Ross added.