THERE are numerous factors which need to be considered when selecting a bull to mate over heifers.
In many cases, the primary aim is to produce a live calf which is born unassisted, with other economic traits (e.g. growth) of secondary importance. Traditionally this has been done by selecting a ‘heifer bull’ to mate over the heifers; that is, a bull with a low birth weight EBV which will produce small calves which are easily calved down by the heifer.
However as birth weight is highly correlated with the other growth traits (e.g. 200, 400 and 600 Day Weight), this has traditionally…
