The breeding objectives at Stellar Livestock are based around the two key pillars of maternal efficiency and marketability. Marketability is achieved with a strong focus on marbling. But what is maternal efficiency?
Maternal efficiency is all about making sure a breeding enterprise is economical. In a self replacing herd, it’s estimated that 75% of the grass grown goes toward maintaining the cow herd. That only leaves us with a quarter of our pasture productivity to produce a saleable product.
There is a tendency for some cattle breeders to focus too singularly on growth traits. Selecting high growth sires can have unintended consequences. Birth weight and mature cow weight are intrinsically correlated to growth traits. High growth genetics also need more feed to achieve the extra kilograms. The Dairy Industry figured this out long ago: Increased output demands an increase in inputs, and grass is not an infinite resource. If you upgrade your four cylinder car to a V8, you also have to increase your fuel budget.
Big cows also tend to have a later maturity pattern which means heifers reach puberty later. And in tough seasons, big cows are the first to fall into an energy deficit. In this situation the first function to shut down is reproduction.
Body composition is also an important factor: We are learning that muscle is a better energy reserve than rib or rump fat as we can build muscle more efficiently than fat. It’s also worth pointing out that rib and rump fat EBVs describe yearling animals and are only moderately correlated to mature cow condition. We can look forward to additional EBVs in the coming years that better describe our mature cows.
Tips For Using EBVs To Select Herd Bulls
- Identify no more than 2 key traits with which you want to make genetic gain in your herd, and set your selection criteria for these to the top 35% percentile band.
- Identify any other traits that need to be above a critical threshold and set your selection criteria to the 80% percentile band to avoid the extremes.
It’s better to have all your sire battery consistently meeting a conservative breeding objective than to secure one elite bull and a bunch of sub-par team mates.