Meeting Market Specifications: Exploiting Breeds and Crossbreeding for Profitable Production of Beef

Dorian J. Garrick
Institute of Veterinary, Animal and Biomedical Sciences,
Massey University, Palmerston North

Introduction

A viable beef production enterprise must provide animals for harvest with the value of the carcass meeting all production costs including adequate profit. This requires that carcasses meet market specifications in terms of quality, size and time of delivery to the processor. Producers can improve profit by increasing the margin between costs of production and the value of the carcass. Improved profit can be achieved by changes in management (see other papers in this Proceedings) including: level of feeding; age/weight at harvest; animal health and growth promotants. This paper considers the use of different genotypes (breeds and breed crosses) to improve profit.

Breeds in Relation to Beef Production System

Producers must identify the relevant performance characteristics of beef breeding cows and their offspring that best suit their farming system. This involves identifying the factors that influence their returns and the factors determining their costs. The major determinant of efficiency of a beef production system is the dollar value of sale product, relative to the quantity of pasture consumed throughout various times of the year. Over half of the pasture consumed in a beef breeding and finishing system is required to maintain the breeding cows and generate replacement heifers.

Accordingly, the reproductive rate of the breeding cows, expressed as calves born or weaned per 100 cows mated is one of the single most important production statistics. Reproductive success involves a number of factors including age at puberty, conception rate, gestation length, calving difficulty, post-partum anoestrus interval (the time from calving to cycling) and mothering ability. A concentrated calving, along with good lactational performance are key factors in converting a high reproductive rate into a heavy weight of calf weaned per cow.

In recent years, the mature weight of cattle has tended to increase in many breeds. This is clearly evident from the published genetic trends available from Breed Societies recording on Group Breedplan (e.g. Angus, Hereford, Simmental). One influence of increased mature weight is to increase weight at weaning. However, a recent study of profitability to weaning has shown that increasing weaning weight by one kg will not increase profitability unless it is associated with less than one kg increase in mature weight of the breeding cow (MacNeil and Newman, 1992). Improved profitability up to weaning therefore requires increasing weaning weight at a greater rate than increases in mature cow size.

Consider the growth of a beef cattle from weaning until harvest. The faster the animal can grow over this period, the less total feed consumed for maintenance, and therefore the greater efficiency of production. However, maintaining high growth rates over winter can be difficult to achieve and requires utilising what is often the most scarce and valuable feed grown. Two production systems presented elsewhere in this Proceedings, achievable for some pastoral farms in New Zealand, involves the generation of 300 kg carcasses by 18 to 20 months or 400 kg carcasses by 27 to 30 months. Growth rates to achieve these two alternative targets have been based on generation or purchase of weaners from 1 May at 250 or 220 kg, respectively.

Breeding and Finishing Enterprises

Breeds differ in their performance attributes for maternal traits (important in breeding cows) and growth and carcass characteristics (important in finished cattle). Breed comparison trials were undertaken by the Ministry of Agriculture and Fisheries in New Zealand during the 1970’s. The female performance of crossbred progeny (except Angus which were purebred and used as a baseline for rankings) in these trials are shown in Table 1. The cows were all mated to Angus or Beef Shorthorn bulls in this study. The reduced age at puberty of dairy cross animals led to higher calving rates as 2 yr olds and improved productivity rankings. Table 1 demonstrates that productivity of the breeding cow up until weaning depends upon both high calving rate to weaning and high weaning weights.

Table 1: Female performance of crossbred cows (Carter and Muller, 1977)

Earlier trials involving at least 12 sires per breed had compared the weaning and carcass weights of crossbred progeny from Angus or Hereford dams. These results are shown in Table 2 and demonstrate the effect of breed of calf. That is, calves sired by breeds with larger mature size tended to have higher weaning weights and the highest carcass weights. Furthermore, these larger sized breeds tended to have leaner offspring when harvested at a similar age.

Table 2: Growth and carcass performance of first-cross progeny from Angus and Hereford cows (Carter and Jones, 1976; Carter and Muller, 1977)

The representatives of these breeds available in New Zealand in the 1990’s may differ in performance from those used in the MAF trails. The important messages from Tables 1 and 2 are that the breeds and their crosses can differ considerably in various performance attributes and no one breed excels for both maternal and growth characteristics. The choice of breeding system (i.e. purebred, crossbred, terminally-sired), in practice, involves compromise between breeding and growth characteristics. In some circumstances, this compromise can be minimised by choosing purebred or crossbred cows with good maternal traits for mating to terminal sires with good carcass attributes. However, identification of the ideal breed or breed cross for a given situation will first require specification of the relative importance of the various breeding and finishing characteristics.

Within-breed Variation

Although the breeds can differ markedly in performance attributes, there is considerable variation between individual sires within a breed. This variation is important to stud breeders for achieving progress in improving characteristics of a breeds. The best individual sires in a "poorer" breed may outperform average individuals in a "superior" breed. Producers should make cost-effective use of superior sires within a breed. Estimated breeding values (EBVs) aid identification of profitable sires. For more information, see "Bull Selection", published by the New Zealand Beef Council, 1994.

Breed Complementarity vs Hybrid Vigour

In many cases crossbred progeny outperform the average of their parent breeds. This phenomenon is known as hybrid vigour, or heterosis and occurs when unrelated breeds or lines are crossed. The extra performance observed through hybrid vigour is simply the recovery of production losses that occurred through inbreeding in the parental breeds. Hybrid vigour is reduced when crossbred cattle are mated together or backcrossed to parental breeds. Some mating plans, such as rotational crossbreeding can be used to maintain high levels of hybrid vigour. Levels of hybrid vigour for beef cattle traits and some systems of crossbreeding are explained in more detail by Baker, 1982.

In addition to exploiting hybrid vigour, crossbreeding in beef cattle has the advantage of allowing breeds to be chosen for complementary characteristics. For example, crosses between dairy and beef breeds can be used to produce breeding cows that, when suitably fed, have superior milking and reproductive ability. Mating these animals to terminal sires with large mature size allows slaughter offspring to be produced with the benefits of growth rate and leanness to attain heavy carcass weights while maintaining smaller, highly productive breeding cows. In this way, the breeds can be chosen to complement each other in a manner not achievable with purebred animals.

Finishing Weaner Cattle to Target Weights

Previous papers in this session have centred on feeding and management to achieve target weight gains for profitable production of 300 or 400 kg carcass weights. However, meeting market specifications using the current grading scheme, involves attaining target levels of finish (assessed by GR tissue depths), in conjunction with the carcass weight. In future, market specifications may include other characteristics such as fat colour and marbling scores.

Figure 1 shows the performance of a five-month sample of steer carcasses processed through Manawatu Beef Packers during 1993. The left-most point on each line represents the average carcass weight and GR tissue depth for a given breed or breed cross. The right-most points represent the expected GR value for carcasses finished to 50 kg above the average harvest weight. Clearly some breeds and breed crosses are not suitable for finishing to heavy weights because carcasses will grade overfat. These lines may underestimate the rate of fattening, in practice, as farmers tend to harvest finished steers at lighter weights than lean steers.

Figure 1 Steer Carcass Weight and GR ex Manawatu Beef Packers

Summary

• Producers must identify the relevant performance characteristics of beef breeding cows and their offspring that best suit their farming system.
• Breeds differ in their performance attributes for maternal traits (important in breeding cows) and growth and carcass characteristics (important in finished cattle).
• The choice of breeding system, in practice, involves compromise between breeding and growth characteristics.
• Within a breed, sires and strains can vary in their performance. Producers should make use of estimated breeding values to identify superior sires.
• Crosses among breeds (or lines within a breed) can be used to exploit hybrid vigour (or heterosis) and, more importantly, to utilise complementary characteristics of different breeds and breed crosses. For example, crossbreeding allows producers to use breeding cows with superior maternal characteristics to produce finished offspring with superior carcass returns.
• Meeting market specifications requires attention to the level of finish (or GR tissue depth) of steers at harvest, in addition to considering carcass weight. Breeds differ in their size for a given level of finish and therefore in their optimal carcass weights.

References

Baker, R.L. 1982. The Place of Crossbreeding in Beef Cattle Improvement. Proceedings of the World Congress on Sheep and Beef Cattle Breeding, Vol. II, 193-208.

Carter, A.H. and Jones, K.R. 1976. Exotic versus Local Beef Breeds. . Proceedings of the Ruakura Farmers’ Conference. Pp 106-107.

Carter, A.H. and Muller, J.P.E. 1977. Exotic Beef Breed Evaluation. Proceedings of the Ruakura Farmers’ Conference. Pp 105-106.

MacNeil, M.D. and Newman, S. 1992. Relative economic values for traits affecting profitability of beef production in Canada. Proceedings of the Beef Improvement Federation, Portland, OR.