Breeding objectives and selection
A breeding objective defines the 'ideal' animal a producer aims to breed and selection is the method by which the producer identifies that animal.
All breeding enterprises should establish breeding objectives and goals and implement selection processes to meet those objectives as part of the overall business planning process.
A breeding objective describes characteristics that affect profit the most, as well as how important each trait is to profit. A breeding objective should be specific, measureable and attainable.
When developing breeding objectives consider:
- A breeding objective is generally specific to a particular market, therefore it is important to understand customer and market requirements.
- Depending on the target market, some traits or characteristics have greater economic importance than others eg growth rate as an influencer of live weight at sale.
- Monitoring the current herd or flock performance against customer or market requirements and considering how this performance and the requirements might change over time.
- Some traits are highly heritable or readily passed on from one generation to another. Greater progress towards breeding objectives can be achieved by targeting traits that are highly heritable.
- Focus on traits of economic importance rather than traits that have more to do with 'tradition' or 'personal preference'.
A breeding objective can be simple eg breed, or more sophisticated eg fat depth.
Regardless of the level of sophistication, it is important to record or list the desired animal traits that impact on enterprise profitability and estimate the relevant importance of each trait. From here the economic impact of changing each important trait can be calculated from financial and production data.
Tools exist to help producers develop breeding objectives:
- A number of breed societies have generic, market-based breeding information available on their respective websites.
- BreedObject is a software package that helps producers establish breeding objectives.
Once producers understand the requirements of the target market and have developed breeding objectives that are aligned to these requirements, they can begin selecting livestock that meet the breeding objectives.
Selection describes the process of choosing animals that meet the requirements of the breeding objective and will, in a breeding enterprise, pass particular traits onto their progeny. Selection should consider both subjectively measured traits (visual assessment) and objectively measured traits (genetic assessment).
Subjective, visual assessment
Visual assessment is an assessment of an animal based on what can be physically seen. While the requirements will vary depending on the enterprise's breeding objectives, traits to look for when visually assessing livestock include:
- The conformation or shape of the animal eg muscling.
- Structure of the animal eg whether the mouth is overshot or undershot.
Objective, genetic assessment
Objective assessment uses actual measurements to assess the relative worth of an animal to an enterprise. One form of objective assessment is genetic evaluation which provides an insight into the genetic makeup of animals. This is particularly useful when sires are being acquired to improve a herd or flock according to the enterprises breeding objectives.
The difficult task of selecting breeding stock based on genetic assessment has been made easier and more precise through estimated breeding values (EBVs) (cattle and goats) and Australian sheep breeding values (ASBVs) (sheep).
Breeding values are calculated using information from each animal's own performance and from the performance of its relatives. This information can help select and breed livestock that will achieve performance targets and improve profitability.
Breeding, classing and culling
Classing and culling play an important role in improving the average genetic merit of a herd or flock.
Producers can class livestock and cull where necessary to achieve market specifications and the enterprises breeding objectives. This may occur prior to selling and be based on factors such as condition score, or prior to breeding and consider more fundamental conformational or genetic traits.
Regardless of when classing occurs, target market specifications should play a major role in the process.