LIFETIME GRAZING of DEVON STEERS on PASTURE
An Example of growing and finishing Devon steers in the Australian environment

Following are results of grazing two similar groups of purebred Devon steers on pastures. The steers underwent a lifetime of pasture feeding under different rainfall regimes and types of pasture.

THE STEERS

Steers in each group were sired by similar bulls. The steers came together at birth or prior to weaning and were grazed in their groups for the remainder of their lives. The first group was born in 1998 and are identified as “T' steers. The second or ‘U' group was born in 1999.

Properly managed grazing lucerne (this stand about 5 years old) produces
large quantities of high quality feed year round

All ‘U' steers and half the ‘T' steers were vaccinated against clostridial diseases as calves. Both groups were dehorned at about 4 months of age. Twice the ‘T' steers were treated with an endectocide: first at about 18 months of age as they entered their second spring and second about 7 weeks prior to sale as they were being moved to lucerne pasture.

‘U' steers received one endectocide at the end of their second spring as the feed flushed coming into summer.

Devon cattle at 8 months of age being weaned on soybean stubble

CLIMATE

Generally the climate is temperate, ranging from summer day temperatures of 35° to winter night temperatures of 5°. Annual rainfall is about 666 mm, with summer dominance, but useful rain can fall at any time of year.

During the life of the steers rainfall was different for each group:

Each group of steers was subject to different rain regimes. Heavy rain fell during both 1998 and 1999. Rain in the finishing period for the ‘T' steers was relatively heavy (6 month average for January to June is 293.4 mm). Rainfall in the year of birth of the ‘U' group was lighter than the ‘T' group but was still above average (666 mm).

PASTURE DESCRIPTION

Pasture systems in Australia for these grazing steers are entirely dependent on rain for growth. The range of pasture types in the region can benefit from rain at any time of the year, including useful pasture growth in mid winter.

The native grasses can have high protein levels in their season of main vegetative growth. Native medics (Medicago spp) are the legumes of dominance because of the relatively high soil pH. The medics or trefoils typically grow from autumn to spring but need good rain early in autumn for germination and continuing falls prior to winter for large bulk of production. Consequently, they do not grow every autumn.

Improved grass species include annual rye grasses and annual phalaris species in winter and Liverseed grass (Urochloa sp) in the summer. Other introduced summer grasses of value are Barnyard grasses and paspalum (Paspalum dilatatum). All the improved species are ephemeral, dependent on rain in their season of activity for production.

Grazing lucerne is the improved pasture type best suited to the environment. Dominant summer rainfall gives enormous bulk of feed in spring, summer and autumn. The variety consumed by steers in this example is highly winter active and grows throughout the year.

As a pasture, lucerne is best grown without companion species. The high digestibility and high protein and carbohydrate levels in lucerne make it ideal improved pasture in the region. When sown as a ‘mono' culture, lucerne provides very effective weed competition and rarely needs assistance to retain its status as the “king of forages”.

At about 18 months old these ‘U' steers are grazing on lucerne established in wheat stubble
under a crop harvested about 3 months previous

During autumn, winter and spring specially sown grazing wheats provide high quality and bulk for grazing steers. These grazing or winter wheats have been specially developed for the Australian environment to provide valuable feed for stock in the cooler months. Sown early in autumn (March) they provide feed through to December if managed properly and receive spring rains.

Sown specially for producing prime stock, grazing wheats have the
capacity to produce big weight gains in the colder months

STEER GRAZING HISTORY

One group of steers was born in 1998 and the other in 1999. Each group of steers spent the whole of their lives grazing grass or lucerne pasture for various periods. Actual grazing periods for each group is described in the next table.

Note: The periods of grazing times on each pasture are indicative only.

To understand the growth of each group of steers their weights were taken as indicated below.

The ‘T' group had a good start in life growing at a rate of 835 g/day to their first weighing at 182 days. Their whole of life growth for 733 days was 655 g/day. On the other hand, the ‘U' steers had a better start (962 g/day for the first 133 days) and continued to grow at a reasonable rate until slaughter at 711 days (837 g/day for whole of life).

SALE RESULTS

Superficially, the two groups were sold at a similar age (22 days older for the ‘T' steers) but the ‘U' steers were much heavier. The weight ranges at sale and the actual sale returns indicate other differences in the two groups.

Ultimately each group of steers was sold into different market segments at similar ages. This came about as a direct result of their weights at sale time.

The lighter ‘T' steers were typical of cattle consigned to the European or Korean markets. Often steers with carcase weights of this size (250 to 280 kg) are used in the Australian meat service industry for restaurants and institutional food suppliers. They were too heavy for the typical supermarket trade that prefers carcases of 225 kg (but will take bodies up to 260 kg).

On the other hand, the heavier ‘U' steers were of a carcase size that suits heavy export grass fed markets in north Asia. These carcases usually exceed 280 kg but are often required over 300 kg.

This heavy steer, one of the ‘U' steers described in the accompanying data,
is showing all the signs of high meat content and ideal finish

Note: Sale price received was based on Curfew Weight

CONCLUSION

With all the similarities between the two groups it is surprising that there were big differences in the financial returns from each group. Rainfall during the lives of the ‘T' steers was higher which would lead to an assumption that these steers should have been better finished with heavier sale weights. Not so!

It appears that the pastures grazed by each group may have caused the difference in returns. The ‘U' group started life on higher quality pasture and were never far from the best quality feed. The other group were never given access to lucerne pasture for any considerable period of time. The ‘U' steers were grazed on lucerne or grazing wheat from weaning until sale.

The extra financial income from the ‘U' group depended on the higher quality pasture feed consumed over the last 18 months of their lives. The extra return per animal was A$288 or an extra 39% over the ‘T' group.