LINN – The Rio Grande Beef Improvement Association recently completed its bull gain test for 2006-2007 at Rio Beef Feedyard in Linn, said Brad Cowan, Texas Cooperative Extension agent in Hidalgo County.
Seventy-eight bulls from 25 consignors and representing four breeds were placed in feed in November to evaluate their genetic potential as herd sires, Cowan said.
“The bulls were measured for daily gain, frame size, muscling, marbling and reproduction based on pelvic area measurements and scrotal circumference,” Cowan said. “The bulls were evaluated within age and breed group.”
“Bulls are assigned to comparable groups based on age, and then performance is ranked within each breed,” said Ronnie Zamora, Extension agent in Starr County.
In the early junior bull calf group (bulls born after January 2006), the champion Santa Gertrudis went to Olivarez Ranch in Mission, and reserve champion went to Encendido Ranch in La Feria. The champion Simbrah was entered by RX Ranch of Ballinger; Filegonia Ranch of Monte Alto won both reserve champion and the first runner-up. The champion Simmental was entered by RX Ranch of Ballinger, and Mallett Simmentals of Lampasas had reserve champion.
In the late senior bull calf group (animals born between November 2005 through January 2006), the champion Santa Gertrudis went to La Campana Ranch in George West, and Cortijo 4 Hermanas Ranch of Mission entered the reserve champion. Champion Simbrah was Whitaker Livestock of Ranger, and reserve champion went to McCrary Farms of Dekalb.
In the late summer yearling bull group (those born before November 2005), Puesta del Sol Ranch in Austin had the champion Santa Gertrudis bull.
“The Rio Grande Valley Beef Improvement Association was formed nine years ago by several forward-looking Rio Grande Valley beef producers representing several breeds,” said Dr. Joe Paschal, Extension’s livestock specialist for the southern region of Texas.
The association was formed when a group of purebred beef cattle producers asked Extension agents in Hidalgo and Cameron counties to help them conduct a bull gain test.
With Paschal’s help, the agents solicit entries, conduct the tests, collect and assimilate the data, and present the awards.
“The bull gain test and a replacement heifer development program with educational field days were their first projects,” Paschal said.
“The overall performance of all the bulls at Rio Beef during the 112-day test yielded an average daily gain of 3.85 pounds per day with very little weather-related stress,” said Mike Risica, owner and manager of Rio Beef Feedyard.
The bulls come in for a 14-day “warm-up” period to become accustomed to the feedyard and the other bulls. Once the 14 days are up, initial weights are taken and the test begins.
Halfway through the test, a mid-test weight is taken to see how the bulls are performing, said Enrique Perez, Extension agent in Cameron County.
“Towards the end of the test all bulls are scanned for ribeye area, fat thickness over the ribs, percent intramuscular fat and rump fat,” Perez said.
The ribeye area is an indicator of muscling, and the fat thickness measurement is a measure of lean meat yield or cutability, Paschal said. The intramuscular fat measurement is an indicator of marbling, the major factor affecting the quality grade of the steer and heifer offspring of these bulls, he said.
Rump fat, a relatively new measurement, indicates how well an animal adapts to good or poor environments. Cows that carry slightly more rump fat tend to be better adapted to their environment than cows that do not, Paschal said.
The bulls also are measured for frame size.
“Bigger cattle (of the same age) require more feed but may not necessarily be more productive,” said Vidal Saenz, Extension agent for Hidalgo County.
The average frame size of the U.S. cow herd has been estimated to be somewhere between 4 and a 5, based on a 12-point scale, and the bulls between 6 and 7, Saenz said.
A mature frame score 4 cow is about 50 inches at the hip, a frame score 5 is 52. A frame 6 bull measures 58 and a 7 bull, 60 inches. Frame sizes of bulls and cows should be not too different in order to keep calving difficulties low and to keep mature size of replacement heifers close to the dam’s, he said.
Scrotal circumference was also measured done during the test.
“Bulls that have larger scrotal circumference are bulls that have reached puberty at an earlier age generally, and sometimes that is transmitted to their heifer offspring,” Cowan said.
If mature bulls have scrotal circumference of less than 34 centimeters, Cowan said, most likely they infertile.
For more information on the Rio Grande Valley Beef Improvement Association, contact a Texas Cooperative Extension office. A list of Extension offices in each county can be located at http://tce.tamu.edu .
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