In 1920 'Monkey' was born, the foundation sire of the Santa Gertrudis breed. One-sixteenth Brahman and fifteen-sixteenths Shorthorn, with the sire being seven-eight Brahman. Monkey was deep, beefy and red in colour. He weighed 498 kilograms at 12 months of age. He was put into the breeding herd in 1923 and sired more then 150 sons before his death in 1932.
Sam Hordern purchased Yulgilbar in 1949.He began to run Shorthorn cattle with a Devon influence until the introduction of the first Santa Gertrudis bull in July 1954.
Yulgilbar Santa Getrudis Stud - Stud No 13 was established by Sam Hordern in July 1954. Now it is the third oldest surviving Santa Gertrudis Stud.
The first production sale held on Yulgilbar was on the 8th September 1966. Held at the 'New Yards' which is an area near the properties airstrip. The sales were held there until 1974 when they were discontinued. Private selling on farm replaced the annual production sale until they were restarted in 2007.
Warenda Sahara was purchased by current manager Rob Sinnamon at auction for a record price of $80,000. Warenda Sahara is a homozygous poll bull with industry leading estimate breeding values (EBV's) and pedigree. He has become the most influential sire at Yulgilbar and arguably one of the all-time greats of the Santa Gertrudis breed. Used heavily for A.I and natural service he has 353 registered progeny to his name. His sons have sold to a top of $32,000 to Graeme Acton in 2012. His females have sold to a top of $10,000.
In 2007 annual productions sales on Yulgilbar were restarted. Not since 1974 had Yulgilbar hosted an annual production sale. Manager Rob Sinnamon restarted the production sales which are now held the first Friday of September every year. The sale is conducted in a purpose built sale venue at the Broadwater division of Yulgilbar.
In 2017 the "Yulgilbar Big Shed" a purpose built sale facility at the Broadwater division of Yulgilbar was constructed. This facility features a sale ring, undercover area for viewing of sale lots and multi level seating ensuring every attendee can see the proceedings. Along with this there is an office, private lounge and caterers facilities. When not being used for the annual production sale the undercover area turns into a cutting arena or space for exhibitors at Yulgilbar's tri-annual Beef Forum & Expo.