Getting the balance right

DAVID AND Jo-Ann Strong from Jugiong in southern New South Wales have spent over 20 years tweaking and refining their beef production system to best match pasture demand and supply. Careful pasture management is geared to ensuring feed is available when the cattle need it most. This enables various classes of cattle to be turned off by October each year whilst still keeping the core breeding herd in reasonable condition to cope with leaner times.

Pamela Lawson

The main enterprise of the Strong's operation is the production of pasture-fed steers, sold to JBS at a target weight of about 450 kilograms at 13-14 months of age. These steers are either pure Angus or increasingly Angus Wagyu F1s, produced through artificial insemination (AI). All the F1 heifers produced are also raised and sold in the same way as the F1 steers. 

The later-calving (non-AI) Angus heifers with their first calves at foot are also sold to repeat buyers each year, as well as AI-produced Angus bulls surplus to requirements as back-up bulls. 

Depending on the season, the Strongs will also buy in 80-100 Angus trade steers during the first quarter of each year, at 6-8 months of age and 280-330kg. The target selling weight for these is also at least 450kg, sold with the homebred steers again before October each year. 

GENETIC GAINS

For more than 20 years, the Strongs have been using AI to improve the genetic base of their 350 head Angus breeding herd. The Angus bloodlines used have been selected for maternal traits and excellent carcase characteristics - specifically eye muscle area (EMA), intramuscular fat (IMF) and positive rib and rump fat for easy-doing cattle. 

Genetics sourced world-wide have gradually produced a base herd of low birthweight, shorter gestation length, moderate mature growth cows, with high eye-muscle and marbling characteristics and positive fat for summer survival. 

To keep mature cow weights (MCW) at a moderate level, Jo-Ann uses bulls with a MCW estimate breeding value (EBV) of less than 100. She also believes the 400-day weight EBV is more important than 600-day weight for producing easy-doing steers that suit their production timeframes.

About 15-20 Angus cows and heifers are AI-ed each year to selected Angus bulls to produce backup bulls and replacement heifers. The rest of the heifers and the older cows (having their fourth calf or more) are AI-ed to Wagyu bulls of Tajima-based genetics. 

TIMING OF OPERATIONS

The Strongs use a fixed time AI program, with insemination taking place around early - mid October each year to calve at the end of July. 

Pregnancy rates of up to 83% have been achieved in the older cows, although rates in the 60s are more typical. Last year saw a disappointing result of 49% in the heifers, but this may have been at least partly due to the very wet, difficult conditions around the insemination date. 

The cows are pregnancy tested six weeks after the AI date, and then joined to backup bulls for six weeks. These later calving animals may be culled if the season dictates and numbers allow. 

The second and third-calvers are joined to purchased Angus bulls for six weeks, with their heifer calves kept as replacements. Jo-Ann believes the older cows are much better at producing the F1 Wagyu progeny than the younger cows and get better AI results as they are under less stress. 

All calves are weaned in January at six months of age. 

CLIMATIC CONDITIONS 

A study of the mean minimum and maximum monthly temperatures at Jugiong since 1995, overlayed with the median monthly rainfall shows that harsh autumns are a feature of the climate and ‘bob tail' springs have become a regular occurrence. 

The Strongs sow grazing crops such as oats (undersown with a ryegrass blend) early each year, with the expectation of some sort of autumn break. Peak total feed demand for the whole beef cattle operation actually occurs in late December each year, making spring growth and carryover feed in the form of silage very important for production. But the Strongs also aim to achieve growth rates in the pasture fed animals of 2kg/day in the lead up to sale during September each year and must keep the breeding herd in reasonable condition to achieve desired calving, weaning and conception rates. 

PASTURE PRODUCTION

To ensure the feed demand of all animals is matched with the feed availability year-round, the Strongs have employed many strategies. These include the application of significant rates of fertiliser to pastures, regular pasture assessment and renovation, and strict monitoring of livestock condition and the use of rotational grazing practices. 

The feedbase on Tiana Park consists of predominantly native pasture paddocks (including red grass and clover) and improved pastures of phalaris, ryegrass, clovers, lucerne, fescue and prairie grass. Other paddocks of rundown improved pastures are gradually being renovated, usually with a forage crop such as oats (typically Bimbil) being undersown with Tetila or Winterstar rye. About 40ha of the lucerne - clover - fescue paddocks are cut each year for silage, yielding up to 260 tonnes in exceptional seasons. Fertiliser is applied to pastures at rates varying from 125-180kg/ha each year, and nitrogen is applied to forage crops throughout winter to promote growth. 

Weed management is another significant issue for the Strongs, to control problematic weeds such a blue thistle. The timing of general spray applications is very important, to minimise the adverse effects on pasture species such as clovers. Spot spraying is therefore undertaken in recently renovated pastures. 

SUPPLY AND QUANTITY

From the spring of 2016 to winter 2017, researchers from the Wagga Agricultural Institute graphed the changes in crude protein and metabolisable energy (ME) in four paddocks on Tiana Park. The sampling showed there was significantly more total energy (quality and quantity) available throughout the study period in improved pasture containing lucerne compared to the other improved pasture paddock, rundown pasture paddock or native pasture paddock. 

Then the researchers used the CSIRO program Grazfeed to calculate the minimum energy requirements for a 240kg weaner steer over the study time period and imposed this over the total ME available from the four paddocks over the same period - see Figure 1. This clearly showed that the lucerne improved paddock was the only one of the four to provide enough ME for the steer to at least maintain weight over the entire period. But the graph also showed that the other paddocks could be used at various times during the period to support growing weaner steers. 

KEEPING IT REAL

This analysis was very useful for demonstrating to the Strongs how their grazing strategy could be manoeuvred to make the most of various pastures throughout the year and maximise animal growth and performance. 

In reality, the Strongs already use a number of very worthwhile grazing strategies to manage their livestock and achieve their production goals. These include:

  • prioritising livestock classes, with the highest priority given to the pasture-fed weaner steers, Wagyu F1 heifers, followed by first-calf cows then breeding cows, 
  • combining livestock assessment (demand and condition of individual animal classes) with pasture assessment (quality and quantity) to implement a rotational grazing program,
  • reducing mob sizes to around 60 cows for example, and subdividing paddocks into 25ha to improve management,
  • dividing animals into small mobs according to their condition, so smaller animals can be given better feed for improved growth, 
  • grazing the various pasture types at times to maximise animal growth, aiming for 1.2kg/day growth in steers on the oats/ryegrass forage crops in July and 3kg/day on the lucerne/fescue/clover pastures coming into spring, and
  • cutting silage in paddocks of surplus feed to be used during times of feed deficit. 

Acknowledgments

Patricia O'Keeffe, Ed Clayton, Helen Burns, John Piltz and Xiangba Zhuoga, Wagga Wagga Agricultural Institute. 

 

Contact:

Jo-Ann Strong

Tiana Park Pastoral Co

0409 622779

jostrong12@gmail.com