Breed selection

In beef production, the principle objectives are:

• weight of beef sold per cow mated or per unit area of grazing land
• quality of beef sold per cow mated or per unit area of grazing land.

A number of variables influence these production objectives:

• fertility
• structural soundness
• survivability/mortality
• growth rate
• maturity rate
• maternal ability
• environmental adaptation
• carcase characteristics.

Genetic variation within breeds

Within breeds, there are variations within the accepted norms. That is, genetic variability exists so that not all animals in late maturing breeds are large or marble poorly, and not all animals in early maturing breeds are small or have sufficient fat cover.

For many traits, there may be as much variation genetically within a breed as there is between breeds.

Variation within a breed is usually an advantage, but is not a pre-requisite to successful crossbreeding. With Brahmans, for example, there is less variation for tick resistance than for other breeds. This is a benefit as most Brahmans have a higher level of tick resistance.

Differences between breeds

Breed selection can be a source of debate. Some breeds have characteristics better suited to certain feed conditions or particular environments than have others. No one breed is the best for all environments and all markets.

There are over 50 breeds of cattle available for selection in Australia. Given certain parameters, such as climate, breeds may be ranked in terms of birth weight, calving difficulty, milk production, growth rate, carcass fat, lean/bone ratio and age of puberty. Differences claimed by many breed groups relative to other breeds are not always supported by quantifiable objective data.

Breed complementarity

The choice of breeds used in a crossbreeding program should consider the complementarity of the different breeds. This is the opportunity to match the good points of two or more breeds.

Complementarity is exploited in specialised crossbreeding systems. An example would be where maternal crossbred cows of small to medium size and optimum milk production might be mated to terminal breed sires noted for good growth rate and high quality carcases.

Fluctuation in genotype

In rotational crossbreeding systems, fluctuation in breed composition for the major economic traits can result in considerable variation among cows and calves between generations. This may be significant if cattle are marketed through saleyards where uniformity may be important.

The table below lists different breeds grouped together because of similar biological performance.

For instance, British breeds are generally earlier maturing and therefore able to fatten on less feed, have high fertility, good eating quality and are more suited to colder climates.

European breeds generally grow faster, have more muscle and mature later than British breeds so therefore need more feed to lay down fat cover.

Tropical breeds are better adapted to poorer nutrition and hotter climates. Their birth weight is generally lower and they often mature later. They have high survivability, greater parasite resistance and therefore greater adaptation to harsher environments than British and European breeds.

Composite breeds are a combination of two or more breeds and the breeds used to make up the composite will determine how the animals will perform under different environments.

Table: Breed group definitions

Adapted from Cattle breed types on the New South Wales Department of Primary Industries website (www.dpi.nsw.gov.au).

The decision on the most appropriate breed to use will depend on the environment in which the cattle will run, your production strategy and target market.

For more information about breed selection visit the Tropical Beef Technology Services website. You may also like to consider attending a Breeding EDGE workshop.