Page 107 - NZ Herefords Magazine 2018

INDIVIDUAL MATERNAL % WEIGHT maternal qualities, and are complementary in carcase and
SYSTEM
(%) (%) CALF/COW
maturity patterns. In addition, the system is relatively easy to
2 BREED CROSS 100 0 8.5 manage and generates its own replacement females, which in
3 BREED CROSS 100 100 23.3 turn provide the benefits from the maternal hybrid vigour that
ROTATIONAL CROSS will be expressed.
2 BREED 33 67 12.7
3 BREED 86 86 20 CROSSBREEDING CONSIDERATIONS
4 BREED 93 93 21.7 Considerations that need to be taken into account regarding
the implementation of a crossbreeding programme include:
COMPOSITE
• Managing and/or sourcing replacement females (depending
2 BREED 50 50 11.6
on the crossbreeding system implemented).
3 BREED 67 67 15.6 • Crossbreeding programmes may require more joining groups
4 BREED 75 75 17.5
than a purebred system. This could be eased by purchasing
5 BREED 80 80 18.6 replacement heifers, although sourcing heifers available on a
6 BREED 83 83 19.3 regular basis with suitable health status and known breeding
Figure 4 – Crossbreeding systems and estimated levels of may be difficult.
hybrid vigour. • Hybrid vigour may result in higher birth weights when
sires of a high growth rate breed are joined to heifers of a
BREED COMPLEMENTARITY smaller breed. Selection of suitable genetics is essential to
Breed complementarity results when combining the strong counteract this negative.
traits of one or more breeds to compensate for the weak traits • Crossbred females may be larger and therefore consume
of another breed. more feed than purebred females. Research has indicated
For example, a Hereford female mated to a European breed that productivity per hectare still favours the crossbred female.
sire (e.g. Charolais, Simmental, Limousin) complement each
other exceptionally well. In general terms, the Hereford female SELECTION AND CROSSBREEDING
contributes early maturity, easy finishing and calving ease, while Crossbreeding should not be seen as an excuse for using ‘low’
the European breed sire contributes high growth and muscle. performing genetics (i.e. bulls) within a breeding programme.
Alternatively, a simple crossbreeding system could utilise Regardless of hybrid vigour, the performance of the crossbred
Hereford and Angus genetics. This example requires two joining herd will depend largely on the genetics of the parent, the
mobs, with the daughters of the Angus sires being joined to the management level and the environment.
Hereford sire and vice versa (known as a criss-cross mating Figure 5 illustrates the benefits of combining selection with
system). These breeds work in this system as they both have crossbreeding.

PRODUCTION RESPONSE COMBINING SELECTION AND CROSSBREEDING

Selection +
crossbreeding

Selection alone
within a herd

PRODUCTION THE DIFFERENCE IS
INCREASED OVER TIME

Crossbreeding
alone

Random mating
within herd

Source: Breeding for Profit, QE 93015, DPI, Qld, 1993.

Figure 5 – Maximum benefit is achieved when the benefits of crossbreeding and selection are combined.

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