Bonnydale Black Simmental

About Us

Bonnydale Black Simmentals is a family business built on hard work, patience, dedication and an unwavering and passionate commitment to our clients and to the Australian beef industry.

The business is operated by brothers Mike and Rob Introvigne and wives Julie and Diane trading as Introvigne Grazing Company.

The original property (157Ha) has been in the family since 1936. Parents, Jim and Rita purchased the property from Rita’s parents in 1964 and registered the Bonnydale stud in 1974. From these humble beginnings the family has built a successful cattle and cropping operation.

The Property

The properties are situated 280 kilometres south of Perth (Western Australia) on top of the Darling Range in the Blackwood River valley district.

The business operates over 5000 hectares and is located in the blue-ribbon agricultural shires of Boyup Brook and Kojonup with the stud based 20 kilometres north east of Bridgetown. The 650 – 750mm rainfall covers the growing season, April/May to November. The undulating terrain is pastured with sub clovers and annual rye grasses. The 1300 head cow herd is run at 1.2 hectares per cow/calf unit with the balance of the herd being 340 heifers to facilitate the continued growth of the herd . Bulls are sold as yearlings at the annual on property sale held in early February each year.

The 4000 hectare cropping program is operated under Tandara Farms and is run separately from the Introvigne Grazing Company cattle operation. This separation of businesses allows Bonnydale Black Simmentals to be managed by a professional team with a sole focus on the continued development of the herd and customer relations.

The 2025 stud herd will see 650 Black Simmental and Simangus registered females mated to begin calving in Jan 2026.  An extensive AI and ET program is undertaken to introduce elite USA genetics.  With the increasing number of elite homebred sires on hand a larger percentage are being paddock mated.

The basis of the Bonnydale Black Simmental herd began in 2005 when the family formed a breeding alliance with Willie and Sharon Altenburg, Altenburg Simmental ranch, Colorado, USA. With both businesses sharing the same philosophy when it comes to breeding cattle it has proven to be an ideal fit to produce elite Simmental embryos for Bonnydale’s program. The mutual respect both families have for each other has led to a tremendous and enduring friendship.

In 2022 Willie and Sharon sold the ASR herd to respected seedstock business Triangle J Ranch under the stewardship of Darby & Annette Line, Miller, Nebraska.  Darby agreed to continue the breeding alliance and the first of these Triangle J embryos were implanted in April 2023.  Willie as agreed to continue his association with Bonnydale sourcing new sires and liaising with Darby to continue delivering elite genetics.