Breeding objectives for beef cattle

Author
Paul L. Charteris
Institute of Veterinary, Animal & Biomedical Sciences,
Massey University, Palmerston North, New Zealand

A sustainable performance-recording programme requires: committed bull buyers; motivated breeders; database and evaluation systems; research and extension. Breedplan provides database and evaluation systems for Breed Societies in New Zealand. Bull breeders are funding the collection and routine analysis of their performance records. Australian Industry funds Breedplan research and development..

This New Zealand Meat Research and Development Council (MRDC) funded research programme was established to ensure the effective delivery of Breedplan to New Zealand's beef cattle breeding industry. The efficacy of genetic improvement can, in part be determined through establishment of economically-based selection objectives. Such selection objectives should be based on based on New Zealand beef cattle breeding, production and marketing circumstances.

Selection objectives are currently being developed for Angus, Hereford and Simmental breeds in New Zealand due to their widespread use in the commercial beef cattle industry and established use of Group Breedplan. For economically based selection objectives to be adopted by bull breeders, they need to feel comfortable with the logic underlying the establishment of selection objectives. This has required close consultation with beef cattle Breed Society representatives and the incorporation of their requirements into the development of selection objectives.

Steps in establishing selection objectives

Characteristion of beef cattle breeding industry structure

Genetic improvement initiated within registered beef cattle herds is transmitted to commercial beef cattle herds via bull sales. The majority of beef cattle slaughtered in New Zealand arise from commercial herds. Thus, selection objectives should be based on requirements of commercial beef cattle farmers. The approach taken in this study is to develop selection objectives for each of Angus, Hereford and Simmental breeds based on how bulls within those breeds are used within the commercial beef cattle and dairy industry in New Zealand.

Characteristion of production and marketing circumstances

Clear definition of breeding, production and marketing circumstances enables the identification of sources of income and expense for that beef cattle production system. New Zealand beef cattle production systems are pasture-based, cows are managed on pasture (often hill country) and their progeny are finished on flatter, more productive pastoral land until 20 months of age or are retained for a second winter and are finished at 27-30 months of age. A beef cattle production system was modelled based on animal production and all sources of income and expenses for one cow unit for two periods representing non-breeding replacement heifers and breeding cows.

A hill country farm was modelled in which all steer progeny and surplus heifer progeny of breeding cows were sold at weaning at a local saleyard. Production parameters represent an annual average for a commercial beef cattle farm, in practice, calf weaning weights would vary between years and cow live weights vary between and within years.

Heifers were general purpose, in which all male progeny and female progeny not required for rebreeding were slaughtered. Heifers were mated at 14-16 months of age to calve at 2 years of age in early August. Rebreeding occurred in November following a 6 week mating period.

Feed requirements of the heifer and her progeny were estimated as a function of growth and maintenance requirements, in addition to cow energy requirements for lactation and pregnancy.

Selection objectives for other beef industry sectors

Selection objectives were developed with the aim of maximising profitability of commercial beef cattle farmers. Sustainable beef industry profitability would see all sectors of the beef industry maintaining profitability. An important question to ask is: would selection objectives aimed at maximising profitability of commercial beef cattle farmers result in improvements in profitability for beef processors. A discussion document was sent to beef cattle processors, inviting them to include their requirements in the development of selection objectives. This document included:

• What traits are of financial importance to your company? Traits are of importance if they decrease costs, improve returns (or both). Processors were asked to assign a score from 1 (no importance) to 10 (of great importance) for a list of traits. A separate list was completed for different market destinations.
• What are concerns about beef processed at your slaughter plants? Processors were asked to rank a list of animal and meat quality factors which may result in lowered profitability for their beef processing plants.
• What traits assume greater economic importance for your company at some time in the future as a result of market or technological change?