In general, animals that are crosses of unrelated breeds, exhibit higher levels of heterosis, due to more heterozygosity, than do crosses of more genetically similar breeds such as a cross of Angus and Hereford. This is why at BlueStone Beef we cross British breeds with Continental European breeds. By combining breeds that have different strengths we harness the effects of breed complementarity.
Heterosis generates the largest improvement in lowly heritable traits. Traits such as reproduction and longevity have low heritability and consequently are most affected by heterosis. Research at Kansas State University has shown composited cows exhibit improvements in calving rates of nearly 4% and an increase in longevity of 1.36 years due to heterotic effects. This increase in productivity is an increase in profitability.
The average scrotal circumference of all BlueStone Beef bulls at just 12 months is an incredible 37.8cm and we have had measurements as high as 44cm at 12 months of age. This is higher than many single breeds bulls at 24 months. Yearling scrotal circumference is important, because it has been found to be favourably genetically correlated with heifer days to calving making it a good measurement for selection of heifer fertility. Increased yearling scrotal circumference is highly heritable (30-45%) and is also associated with earlier age at puberty, increased semen production and improved semen quality. Early maturity and increased fertility is a twofold increase on return on investment.
Heterosis has increased the longevity of each sire, yet the ability to use sires as yearlings also means greater lifetime production.
Increased fertility in females means we are consistently seeing above 96% pregnancy testing results off just a 42-day joining period.
This superior early mature growth results in reduced days to slaughter. This increased production efficiency means BlueStone Beef progeny have a reduced emission intensity numbers in comparison to single breed herds. Increased growth has not compromised quality. Research has shown that there is limited opportunity to select among or within breeds to achieve high levels of marbling or high levels of fat in the longissimus muscle simultaneously with achieving a high percentage of retail product in the carcass. This research has shown Composite breeds achieve a balance between favourable carcass composition and desirable carcass quality grade at optimum slaughter weights.
By using heterosis (hybrid vigour) we are seeing huge efficiencies in inputs, are achieving high early growth rates and consequently meet market specifications earlier. This increase in production efficiency correlates with reduced emissions intensity numbers.
