According to the New South Wales Department of Primary Industries, yearlings are often aged between 12-18 months and are used as they allow the introduction of superior genetic material into a herd a year earlier than normal and this results in faster genetic improvement.
This can help farmers extend their bulls’ working lives by a year, which can result in a lower spend of bulls for your herd.
Being young, they have a higher chance of being free of structural problems, lean, keen and exuberant.
Although they have a lot to offer, they need to be effectively managed as their age and psychological status require it.
The difference between a yearling and a bull
This is like big brother versus little brother. Yearlings are still growing, and they are still learning. Even though they are more agile and fitter, they are not necessarily stronger than older bulls. This makes them prone to get injured more often, especially if in with other males.
To keep them in top condition, keeping on top of internal and external parasites is essential.
Why use young stock?
A lot of cattle producers prefer to use yearlings as they are much easier to manage than older and much larger and stronger bulls. Being quieter they often mix better with others in the paddock.
The cost of a yearling bull is significantly cheaper to produce and with an extended year in production from an older bull, costs will be spread over more calves produced.
By using genetically superior bulls as young as possible to yearling heifers, you can maximise genetic improvements by lowering generation intervals.
Are yearlings sexually mature and up to the job?
Yearlings are up to the job if they are well-grown, in good condition, are 12 months or older, with a scrotal circumference of 32cm or more (12-18 month).
Serving ability
Inexperienced, a little clumsy and awkward - but they will improve in time and with practice.
Management when it comes to mating
Yearlings are better in the paddock with their peers. When older bulls are joined, the dominance begins, and the job can become wasteful and inefficient as the job turns into a tussling match.
Mating loads of 25-30 are recommended for yearlings.
Can a yearling reach my large cows?
One wonders how this is physically possible sometimes, but sex can be a wonderful motivator.
Do yearling bulls have smaller calves?
Funnily enough, you would be surprised at how many cattle producers think that young bulls are going to sire small calves. There is no relationship between the size of the bull and the weights of his calves. The birth weight of a calf is heritable, so genetics will decide the size of the calf.
The three most important things to remember: join them alone or with bulls of their own age; join yearling bulls for six to eight weeks and then spell them for at least three months; and finally, when the job is done, they will be a little weary so move them to a paddock with a good lot of feed, a nice shady tree and ample water.
Source: https://www.dpi.nsw.gov.au/animals-and-livestock/beef-cattle/breeding/bull-selection/yearling-bulls