Missing out on even 10 per cent of early growth potential in black and white bulls or continental cross beef cattle could increase finishing times by 14 days and feed requirements by a minimum of 220kg.
This is the warning from KW nutritionist Charlotte Ward, who says these cattle are also harder to finish to market requirements, reducing income and further eroding margins.
She says: “Time to slaughter, quality of finish and total feed cost are three critical factors which have a major impact on beef margins and overall unit profitability.
“Maximising early liveweight gain, when feed is converted into growth most efficiently, is one of the most cost-effective ways to improve all three factors.
“But remember, the aim is for lean [muscle] growth and LWG, so it is also important to minimise fat deposition during that early growth phase.”
Ms Ward explains fast rates of lean tissue growth can only be achieved when the animal’s requirement for metabolisable protein (MP) is consistently met.
That MP supply comes from a combination of rumen microbial protein and rumen-bypass protein, so the key to driving early lean growth is to ensure a good supply of both by feeding higher quality protein during the first five months.
“Increasing ration rumen-bypass protein levels not only increases overall MP levels, but also acts as an insurance to maintain MP supply whenever rumen fermentation is compromised,” Ms Ward says.
“This often happens following the stress of weaning, changes in social hierarchy or excess heat in summer, for example, so the improved MP supply is critical until animals are fully weaned, growing well and settled into new groups.”
Ms Ward explains the traditional approach to grower ration formulation is to focus on low-cost protein sources to top up crude protein (CP) levels to the typical 15-17 per cent target.
Boosting the supply of rumenbypass protein – otherwise known as digestible undegraded protein (DUP) – without increasing overall CP levels requires the focus to shift to higher quality protein feeds, and in some instances dedicated DUP supplements.
“The aim is to drive lean growth until switching to a finisher ration that contains 2-5 per cent less CP, plus up to 0.5-1MJ ME/kg DM extra energy and more than 30 per cent starch to support quick finishing by boosting fat deposition,” Ms Ward says.
It is an approach particularly well-suited to black and white bulls and late maturing continental cattle, such as Charlolais, Limousin and Simmental, says Ms Ward.
These cattle tend to continue pushing nutrients into growth rather than laying down fat unless early growth is maximised.
“If most of the lean growth can be achieved early on, cattle are more likely to partition energy towards fat cover, enabling target slaughter weights and confirmation to be more easily and quickly achieved,” Ms Ward concludes.
“The net result is a higher average carcase value, quicker finishing and more animals finished per year, all of which increases farm income.”