Inclusion of Carcass and Meat Quality Traits Into Murray Grey Selection Programmes

Paul L. Charteris
Department of Animal Science, Massey University, Palmerston North, New Zealand

One commonly asked question by Murray Grey breeders is "in what direction should we improve our breed? - should we be aiming to improve growth rates, fertility, carcass and meat quality or milking and mothering ability? This articles presents some considerations for breeders considering selecting cattle for carcass and meat quality traits.

Which traits?

The importance of carcass and meat quality traits to the beef cattle industry is beyond question. However, their practical improvement from a genetic standpoint is limited by the fact that no industry-wide programme has been established for their improvement. Indirectly however, through positive genetic associations between growth rate, live weight and eye muscle area, it appears likely that breeders have been selecting for improved lean meat yield already.

Genetic gains made within registered herds accrue to other beef industry participants through sale of bulls to commercial beef cattle farmers. Most farmers are in the business to make a profit, this can be affected through purchase of bulls from registered herds which increase income, decrease expenses (or both). The current New Zealand beef carcass grading and classification system rewards farmers for cattle with higher carcass weights, decreased fat depth and conformation score (expressed on a three point scale). Since farmers are rewarded for increased carcass weight, breeding bulls are probably sourced which with increased growth and live weight.

Motivation for breeding cattle with superior carcass and meat quality characteristics would have to arise through improved bull prices paid by beef cattle farmers. Farmers would in-turn have to be motivated to pay more for bulls from which a high percentage of progeny meet the requirements of processors and attract premium prices. Recent initiatives to improve carcass feedback to farmers may provide motivation to purchase bulls with improved carcass and meat quality.

A wish list of carcass and meat quality traits to improve may include:

Which of the above traits would be important for improvement in Murray Grey selection programmes?. Some traits such as eye muscle area and fat depth can be improved relatively efficiently by ultrasound scanning potential breeding animals and incorporation of scanning measures into a genetic evaluation.

Other traits such as tenderness, meat colour and fat colour are more difficult to improve through selection. In addition, there are negative genetic correlations between some meat quality traits, for example improving marbling can lead to a decrease in lean meat yield. In addition, negative genetic correlations between lean meat yield and fertility traits generally means those breeds which are the highest yielding have fertility problems including poor conception rates and calving difficulty. This is one of the reasons we use specialist terminal sire breeds.

What are the barriers?

Problems associated with improvement of carcass and meat quality traits include:

1. Misinterpreting the competition. Sometimes breeders consider other Breed Societies as the competitors (rather than as cooperators), greater cooperation between societies in establishing selection programmes can help to pool expertise and spread capital costs over greater numbers of animals evaluated.
2. Carcass and meat quality traits of primary importance to beef retailers and consumers may not be included in beef cattle carcass grading and classification, therefore do not affect income of commercial beef cattle farmers.
3. Due to the low frequency of pedigree recording, the use of multiple sire mating or confounding of sire with management group, little useful information for genetic evaluation purposes can be collected from the commercial beef cattle industry.
4. Most meat quality traits cannot be evaluated accurately in breeding animals.
5. Few breeding animals from registered herds are themselves slaughtered at market weight or age, hence useful carcass measures are not available on these animals directly.
6. Beef cattle Breed Societies traditionally spend funds on breed promotion or cattle shows and very little on breeding related research.
7. During a beef downturn it becomes very difficult to motivate breeders to invest in selection programmes to improve carcass and meat quality traits. However benefits from selection accrue many years in the future, therefore any selection programme initiated should be aimed at improving future industry profitability.
8. Lack of motivation, due to the long term nature of selection programmes, often breeders may lose interest before the real benefits arise.
9. Mode of improvement, should traits be best selected using ultrasound, progeny testing, measures on indicator traits or gene mapping, what technologies are currently available in New Zealand, which are the most cost effective and accurate?
10. Who benefits from genetic improvement, selection programmes which improve quality of beef product with no increase in beef price or market share can result in over 90% of benefits from selection accruing to consumers.
11. Often improved carcass management will result in faster increases in meat quality than genetic improvement, for example minimising stress prior to slaughter, the use of hot-boning or electrical stimulation.

Any Murray Grey initiative to improve carcass and meat quality traits must be based on a clear understanding of what traits should be improved with respect to current and future market requirements. Any programme should aim to maximise industry benefit from genetic improvement of Murray Grey cattle.