Farming to the extremes at Hawkdun Station

// Pests and Diseases

Beef + Lamb New Zealand (B+LNZ) recently hosted a Farming for Profit (F4P) field day at Central Otago’s Hawkdun Station.

image of cows in central otago

It was the inaugural event on this historic property, attracting over 100 sheep and beef farmers eager to learn about farm system optimisation in the rugged St Bathans area.  

Over the past 50 years, the Cavanagh family has transformed Hawkdun Station. Starting from humble beginnings, the property has evolved into a resilient farm system, successfully navigating the challenges of the upper Manuherikia Valley's challenging environment.  

Through strategic fencing, fertility enhancements, pasture improvements, and irrigation, the Cavanaghs have enhanced productivity and sustainability across their 5350-hectare station.

Key takeaways from the day 

Innovations in pest management 

Hamish Cavanagh shared his strategies for managing horehound, a persistent weed plaguing lucerne paddocks, including sowing lucerne/grass mixes to combat horehound intrusion.  

The introduction of Hexogon Plus, guided by AgriSpray’s Troy Mackey, emerged as a promising solution to weed control on the property. In order to achieve the best results with this product Troy recommends:  

  • Use Hexogon Plus only on established lucerne stands (aged 2-3 years or older). 
  • Apply after the first graze/cut – less lucerne leaf results in better weed exposure. 
  • Apply on the warmest day possible (when temperatures are 22-23°C and rising) and ideally when there will be further warm days to follow. 
  • Make sure you use 300 litres of water (150–200 litres won’t work). 
  • Be careful when planting other species with lucerne as it will take some of these out (e.g. clovers). Note that the plant-back period for brassicas is 12–18 months for brassicas and 18-24 months for legumes. 

Optimising beef production 

Hawkdun Station runs a relatively high proportion of cattle (60:40 sheep:cattle ratio), utilising high quality Angus genetics that have been selected to perform in the harsh climate of St Bathans. During the day, the Cavanaghs shared how they have established a breeding herd resilient to the region's challenges.  

They shared how they have invested into high quality bull genetics over the years, with the aim of breeding functional cattle, with moderate frame, good intramuscular fat levels, and fast growth. 

The Cavanaghs emphasised how a recent introduction of artificial insemination (AI) has further enhanced the quality of replacement heifers going into the breeding herd. To justify the cost, the best 5-6 yearling bulls from the AI programme are utilised for breeding. 

Improvements have also been made to the calving spread, using date scanning to remove later-calving cows. The AI programme has also helped reduce calving spread, with cows joined to AI cycling early the following year.  

Another key to success for the beef herd is achieving good conception rates. Attention is paid to cow body condition in autumn, and in drier seasons cows are weaned earlier to try and allow them to put some weight on prior to winter. This helps to ensure that cows are in good condition when they calve at the beginning of October, which flows on to mating.  

Changes have also recently been made to the finishing policy. Originally non-replacement calves were sold as yearlings; however the aim is now to take them through to 18–20months and sell into the feedlots. This policy provides flexibility for dry years where these animals can be offloaded early.  

Evolution of the sheep flock  

The evolution of Hawkdun Station's sheep flock from Merinos to Romdales reflects a commitment to adaptability and genetic improvement. Son Richie’s establishment of a Suff-Tex stud underscores the family's dedication to producing hardy, high-performing stock capable of thriving in the station's extreme climate. 

Worm-tolerance is also a key trait of importance, and the aim is to reduce reliance on drenching in the future. Worm-tolerant sires are also used, stud ewes are not drenched at all, and lambs are only given two drenches in their lifetime. The plan is to put the stud on SIL soon.  

The investment in genetics has created a flock which is capable of achieving good levels of performance in the extreme environment at Hawkdun Station. Scanning percentage is typically around 165% and tailing percentage is 135%. Androvax has been used in the past to further lift the reproductive performance of the ewe flock, but this resulted in too many multiples. In a normal season, all of the non-replacement lambs are finished, averaging 17.5 kg carcass weight.  

Summer country 

Peter Young from Farm Advisory Services spoke about the importance of the summer country on this property. He emphasised that profitability in a crossbred ewe flock is driven by ewe reproductive rate and lamb growth rates. Ewe reproductive rate is driven by genetics and management of ewe body condition score.  

The summer country at Hawkdun Station plays an important role, carrying ewes during the critical post-weaning period, which reduces pressure on the lower country.  

Hamish has found that on the summer country the ewes generally put on condition for the first month, maintain for the second month and might only drop off for the last couple of weeks.  

Because of its importance to the wider farm system, it is therefore imperative that the productive potential of the summer country is maintained. This is done through regular soil testing and application of maintenance fertiliser.  

Ravensdown Fertiliser Consultant, Nicole Adam, discussed the fertiliser programme on the summer country which is on a 3-year rotation of sulphur-super 30.  

Research shows that for longer fertiliser rotations, the inclusion of elemental sulphur is beneficial, and this product provides both fast-acting sulphate-S and medium-term release elemental-S. The fertiliser mix also includes molybdenum to support the growth of clovers. Molybdenum becomes less available at low pH, and because it is difficult to justify flying lime on to this country, addition of molybdenum to the fertiliser mix is useful for supporting clover growth.  

Hamish Cavanagh notes that there is a clear difference in growth and legume content once fertiliser is applied, and this translates to heavier lambs weaned off the blocks which have had the most-recent application of fertiliser.