Guidelines for managing the grazing system to achieve livestock performance targets
The stocking rate (DSE/ha) and total number of cattle sold each year has a major impact on the profitability of southern beef enterprises. Retail yield is affected by muscling (principally due to genetics) and fatness (partly due to genetics and partly due to quantity and quality of feed consumed). It is important to know your herd capability in regard to muscularity, yield and fatness.
Sale animals typically include weaners, cull breeding stock and traded stock. The predicted sale liveweight, carcase weight and any other characteristic required for the target market need to be within the specified range to ensure market specifications are met at the point of sale. The liveweights at different ages are well known for most prime beef markets. So are the minimum and maximum backfat requirements for different cattle liveweights.
A goal is to have no more than 10% of animals fall outside the target market specifications for age, sex, dentition, weight (live or carcase), muscle and fat. To achieve this, manage the grazing and husbandry system to reach the desired stock performance and market outcomes.
Growth rate will affect the weight for age, fatness, marbling and ossification score:
-Weight for age is influenced by growth rate. A faster growth rate results in heavier and fatter animals of the same age, or younger animals of the same weight. The main contributor to growth rate is how the supply and quality of feed on offer is managed.
-Fatness and marbling are mainly affected by growth rate. A higher growth rate within a herd sale group results in increased fat thickness and intra-muscular (marbling) fat content at the same weight. These are influenced by how you manage feed quality and supply.
-Ossification score increases as animals get older. Also, at the same age, heifers have higher ossification scores than steers. You can ensure animals retain ossification scores below the maximum allowable for Meat Standards Australia quality grading (less than 300 or as low as 200 in some markets) by ensuring a whole-of-life growth rate of more than 0.6kg/day.
Poor growth early in life (up to weaning) influences the rate of protein and fat gain. Cattle subjected to limited feed supply before reaching 250kg or 40% of mature weight (and for a period of at least two months with a growth rate of less than 0.4kg/day) will grow slower and become fatter when well fed later in life. Marbling will be lower than expected at the same fat thickness. Take this into account when planning the beef breeding enterprise around the seasonal pattens of pasture growth.
Animals fed to achieve target weights more quickly will eat less feed per kilogram gain. So plan carefully how your sale cattle need to grow to meet the market specifications, by:
-Calculating the daily growth rate required from your starting point (say weaning) to the expected sale date for the stock to achieve the necessary sale weight (see the Example of calculations for growth rate box below).
-Providing the cattle with pastures of sufficient quantity and quality to achieve the predicted growth rate.
-Routinely weighing cattle from weaning up to point of sale to compare their actual liveweight with the predicted growth path to ensure that they reach the target weight at sale.
The benefits will be greater precision in marketing, a higher proportion of your cattle meeting market specifications and a higher price.
The focus needs to be on the relationship between cattle nutrient requirements, pasture availability and quality and how these interact to affect rate of growth, composition of growth and product quality. The basic principles of animal nutrition, their relationship to animal performance and the conversion of pastures to animal product.
At all times, it is important that costs associated with achieving the target growth path are considered together with returns from the expected outcomes. Flexible management is required to incorporate both short-term and long-term targets and multiple options for stock production. If you find that your cattle are:
-Doing better than planned. Consider new options such as: an alternative market; sell earlier; conserve excess pasture; or purchase additional stock.
-Not meeting target. Recalculate the growth rate and develop a new strategy such as: an alternative market; alternative pasture sources; supplementary feeding, lot feeding; or alternative pasture management.
The timing of these decisions needs to be early enough to allow the growth path to be adjusted to meet the timing of the revised point of sale.
Other corrective actions may be based on market feedback. Although this is received after the current sale event it can be used to improve the planning and management of the nutrition and health of your cattle to meet future market specifications.
An additional option is to change the genetic characteristics of the animals selected for mating, if you are unable to deliver to the specifications required in your environment with the current genetics. You need to ensure that this will be profitable and feasible, and recognise that this is a longer-term solution.
What to measure and when
Ongoing measurements need to be taken for:
-Liveweight and any other characteristics included in the target market specifications that can be monitored for live animals.
This may involve one or a combination of:
-Real-time ultrasound measurements of fat depth, marbling score and eye-muscle area;
-Visual appraisal of muscle and fat score;
– Dentition; or
-Pregnancy testing of females.
-For liveweight and growth rate: measurement of growing stock should begin at weaning; then at least every three months (more frequently with rapidly changing pasture conditions) until two months before sale; and then when it is most appropriate for the feed conditions and target market(s).
-The percentage of your animals that met target market specifications, when they were sold. Collect carcase feedback when available.
Plan stock health treatments to ensure there is no restriction to market access. Comply with the manufacturer’s instructions for use.
