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Using large muscular breeds to improve world beef production

by B. Vissac

The beef consumed throughout the world comes from three main types of enterprises:

  1. Dairy herds where females are milked and meat is a by-product of milk production.
  2. Single suckler herds (cow-calf operations) where specialized beef breeds (which tend to be small and fat) are used in environments that are favourable to beef cattle raising (i.e. grassland areas with a temperate climate).
  3. Single suckler herds where, because of unfavourable conditions of climate, disease, and/or nutrition, local cattle adapted to adverse environments are utilized.

The breeds used in these three situations generally lack the muscular growth potential needed to meet the modern consumer's demand for lean, tender meat. This accounts for the efforts made in the last 20 years to improve beef cattle for meat production, principally by encouraging the use in crossbreeding of breeds with a high muscular growth potential. These are primarily continental European breeds raised in favourable environments and selected according to objectives (work and meat) that give full scope for the manifestation of this trait.

B. Vissac is Head of the Animal Genetics Department at the National Centre for Zootechnical Research (Centre national de recherches zootechniques), 78350 Jouyen-Josas, France. The work described in this article was carried out by the author and B. Bibe, J.L. Foulley, J. Frebling and F. Menissier.

After an initial over-optimistic phase in which the muscular growth potential of “exotic” breeds generally showed spectacular development in the first generation crosses, there appeared various shortcomings in the fitness components of the crosses (particularly females). The problem of optimum utilization of exotic genetic material with a highly developed musculature was then approached with a view to increasing meat production when starting from an indigenous female foundation stock. What, in this situation, is the best crossing scheme to use? The answer to this question depends on several considerations concerning the genetic material:

  1. The relative importance of hybrid vigour and of additive gene effects on the desired trait. This will determine the method of crossing to use, i.e. systematic crosses for the market or creation of new breed types. The first method, in contrast to the second, leads to maximum manifestation of hybrid vigour.

  2. The importance of direct effects compared with maternal effects of the genes determining a given trait. In this connexion, the independence (and even antagonism) which seems to appear statistically between breed types for these two kinds of effects can lead to the use of “muscular breeds” to produce calves entirely for slaughter (terminal cross), or from which the females will be used for breeding for only a limited number of reproduction cycles or not at all. This leads us to determine:

    1. A paternal value or component of breeds, for one or more traits; this appears when comparing the meat value of the progeny of bulls of these breeds crossed with a given type of female.
    2. A maternal value or component of the same breeds, i.e. that manifested for one or several traits influencing production efficiency when we compare females of these breeds mated with a single breed of bull.

  3. The adaptation of the breeds concerned to the production environment and, more specifically, to climatic, health, and nutritional factors comprising that environment. What proportion of genes of local breeds should be kept for adaptation to one or another natural or manmade stress (for example, suckling or artificial feeding) in introducing improved breeds?

The research conducted in France can provide some information on these aspects because:

Improvement of meat production from the dairy herd

The process of selection for milk production leading to the gradual replacement of less productive breeds, strains or lines by others highly specialized for milk production makes it possible to rapidly increase meat production independently of milk by crossing the lower yielding cows (30 percent on average) with bulls of the beef breeds.

In general we are dealing with small-or medium-sized farms using artificial insemination. First generation crosses principally comprise heifers that are managed intensively, inseminated from a bull of a small beef breed, and probably slaughtered after an early first calving. This establishes a fattening unit of “once-bred” heifers that is partly self-replacing (FAO, 1972). However, when the milk yield is low and the farm large, milking may be given up and cows bred to beef bulls and used for suckler calf production (e.g. in the United Kingdom and Ireland).

In any case, as the aim generally remains a terminal type cross, the tendency will be to choose beef breed males on the basis of their paternal components or values mentioned above, as reflected by the calves' potential for muscular growth.

In line with this approach, the French insemination centres concerned, in liaison with the National Institute for Agricultural Research (INRA), have been developing programmes since 1955 that are designed to create. select and compare beef strains for use in terminal crossing (Centre national de recherches zootechniques, 1972). The strains studied have consisted of:

  1. Registered animals (Charolais, Limousin, Blonde d'Aquitaine) of normal type, as distinct from the type with muscular hypert ophy or double-muscling. The percentage of isolation of strains in the registered population varies according to breed, being higher in Blonde d'Aquitaine and Limousin, where the selection schemes for terminal crossing are tending to lead to completely isolated strains.

  2. Breed crosses between registered animals of normal type. The breed combinations are designed to bring together more compact genetic types having higher growth potential (Charolais, Maine-Anjou) with longer bodied and taller breeds (Blonde d'Aquitaine, Limousin) which for a given weight at birth have a lower frequency of calving difficulties.

  3. Crosses between animals with muscular hypertrophy. Unlike the two preceding categories, which are selected by the insemination cooperatives, this operation is carried out by INRA on its Carmaux farm which has two herds of female crosses: Charolais X Blonde d'Aquitaine and Maine-Anjou X Limousin or Blonde d'Aquitaine. In this and the preceding case, the schemes tend toward the production of isolated populations. Males of all these strains are first subject to individual within-strain selection and are then simultaneously progeny tested in comparison with a national control lot (Charolais, Limousin or Blonde d'Aquitaine) according to the value of their crossbred progency out of dairy females; the female base is progressively becoming Friesian. The crossbred calves, initially raised for veal and recorded on the farm, are increasingly being recorded at a testing station, half being slaughtered at 15 months and half at 18 months, thus giving a comparison of strains based on different ages at slaughter (Centre national de recherches zootechniques, 1972).

Eleventh rib from the carcass of…

…a double-muscled Charolais bull

Although the initial objectives of bull selection by both performance and progeny tests were designed to improve only the muscular growth potential of the animals or their progeny, other criteria have gradually been introduced into the index:

  1. Efficiency of feed utilization (independent of growth rate).

  2. Meat quality (some components of which can be detrimentally affected by increase in muscularity).

  3. Ease of calving (direct effect). Indices restricting genetic progress in birth weight have been constructed, based on the males used for crossing; moreover, semen distribution can be based on the bull's birth weight index on the one hand, and on the dairy females' ease of calving on the other. If little or nothing is known about the ease of calving, the female population can be classified by age and breed and according to size of pelvic opening or weight, i.e. estimated size for each age and breed class based on a small sample of individuals (Menissier et al., 1975).

In fact, it is becoming increasingly difficult for a single strain to meet all the objectives sought in a terminal cross. These objectives vary widely according to:

  1. Calving age and ease of calving of females. Some insemination cooperatives have therefore been involved in the formation of strains known as “maximal” (no limitation on increase in weight at birth) and “optimal” (strict limitation of the increase), the latter being mainly confined to early-calving heifers. Such an approach should be able to provide for the most rational utilization of the pelvic passage which, in the long run and with only a single calf, in the female must constitute a basic limiting factor to beef production.

  2. Type of production of crossbreds (especially females), i.e. milk X meat. In this connexion, increased muscular development within strains or between strains is generally accompanied in crosses by a delay in body maturity. Thus the use of double-muscled bulls on Friesian cows delays by one to two months the age at which the carcass of the crossbred animal shows a given fat percentage. This can be a considerable advantage in the case of crossbred females which under an intensive management system (slaughter at about 14 to 16 months) can thus reach slaughter weight without getting too fat.

Table 1. Comparison of French beef breeds, breeding phase1

TraitMaine-AnjouCharolaisLimousin
Sires2Dans3Sires2Dams3Sires2Dams3
Calf weaning rate for first three seasons%-59-54-64
Very difficult calvings       
at 2 years
%585640573621
at 3 years
%47432446170
Calf weight at weaning (6 months) for first three seasonskg214219211215207198
Weight of dam after calving at 4 yearskg-624-652-569
Productivity: weaned calf weight/ dam's metabolic weight -1.16-1.01-1.22

1 This comparison is based on results of a factorially designed experiment conducted with purebreds and crossbreds at the INRA experimental farm at Galle. Avoid 18800, France.
2 Progeny of sires of this breed in purebreeding and in crossbreeding with the other breeds.
3 Progeny of dams of this breed in purebreeding and in crossbreeding with the other breeds.

On the other hand, females produced by doublemuscled bulls will show a reduction in fitness (sexual maturity, ease of calving), so that such bulls are less used in systems involving slaughter of females after an early calving (Bibe et al., 1974).

The field is thus open for competition between beef cattle strains designed for crossing with dairy females by insemination. Comparative data should now be refined according to the type of female being crossed and the type of meat production. To be effective, an analysis of the results will make it increasingly necessary to coordinate experiments because it suggests an easy way of increasing meat production independently of milk in industrialized countries which have mainly dairy cattle bred by artificial insemination.

Improvement of meat production from specialized beef herds

In systems where female progeny are normally kept for breeding, numerous shortcomings of “muscular breeds” in extensive production systems have appeared, particularly in the fitness components. These observations are logical enough, considering the artificial environment in which the animals have sometimes been maintained in small-and medium-sized herds, i.e. calving supervision and assistance, control of heat periods, supplementary feeding of calves (nurse cows), and housing in winter and during the night in summer.

The results of experiments in France and other countries reveal a genetic antagonism between the calves' potential for muscular growth and female fitness components; in the case of traits depending on both the calf's and the dam's genotype (e.g. weight at weaning), this antagonism seems to involve the offspring's growth genes on the one hand and the genes controlling the dam's milk production and maternal behaviour on the other. This conclusion emerges clearly from the comparisons that can be made (a) between French breeds of variable size and muscularity raised in specialized beef herds; (b) between Charolais strains selected in different countries (the differences in musculature between these strains, e.g. between Brazilian Charolais and United States Charolais specifically selected for terminal crosses, are greater than those found on average between animals of different breeds) and (c) between progeny of bulls. Here, the French results confirm those obtained in the United States on the antagonism between the direct and material effects determining weight at weaning.

Such observations lead us to seek the best equilibrium in genetic structure, either by selection within breeds or in crossbred populations, or through systematic crossbreeding. The first method will seek to exploit mainly the additive and epistatic effects of genes. The second, which is more difficult to implement, will also involve dominance effects, and above all, complementarity between the calf's and the dam's genes which will depend, in particular, on the order of the introduction of breeds in the crossing schemes.

The search for such equilibria implies an analysis of the genetic variability between and within “muscular breeds” and smaller beef breeds (Hereford, Aberdeen-Angus). The experimental and improvement programmes undertaken in central France in the areas where specialized beef production predominates have been carried out with precisely this aim.

Table 2. Comparison of French beef breeds, fattening phase1

TraitMaine-AnjouCharolaisLimousin
15
months
18
months
15
months
18
months
15
months
18
months
Daily weight gaing/day1 5211 3481 4691 2761 3991 284
Feed consumption indexfeed kg/gain kg7.78.87.58.67.28.2
Final weightkg593700564676531654
True dressing yield%67.167.367.767.367.769.3
Hot carcass weightkg331399316382302386
Body composition (11th rib)       
Meat %
%67.063.869.366.769.669.2
Fat %
%16.419.214.716.713.615.6
  Francs
Productivity       
Feeding (cost)
 1 1701 9181 0961 7751 0011 702
Meat (income)
 3 7674 3253 7164 3233 5864 535
Profit (income minus cost)
 2 5972 4072 6202 5482 5852 833

1 This comparison is based on results of experiments conducted with purebreds and crosses at the INRA experimental farm at Galles, Avord 18800, France. Average values are for paternal and maternal breeds in purebreeding and crossbreeding (average by row and column for a given breed).

Studies on between-breed variation. A factorial plan of crosses between samples of animals representing the registered populations of the three main French beef breeds (Charolais, Limousin, Maine-Anjou) was set up on the Bourges experimental farm, which also has a purebred Hereford control herd. For practical reasons, the females are zero-grazed. The results of the first four years of operation presented in Tables 1 and 2 can be summarized as follows (Menissier et al., 1974, 1975):

Studies on within-breed variation. Since selection for fitness proved necessary in the case of the “muscular” French breeds, it was essential to find more efficient methods than natural selection, which was considered adequate under extensive conditions (e.g. in North America and Australia) with breeds of British origin. This is the object of selection schemes for bulls of beef breeds used for artificial insemination in France in specialized beef breeding areas (Foulley and Menissier, 1974). The schemes include in particular a station test of female progeny — a comparison of 20 female offspring per bull, from weaning to 30 months, which are fed intensively so that they can be calved down at 2 years. Although this system is a considerable departure from more extensive methods adopted in many countries and covers only a short phase of the animal's reproductive life, it was considered a priori to be effective for “muscular breeds.”

Sardinian, Modica, Brown Swiss and first-cross cows with Charolais and Piedmont in the experimental beef herd at the Sardinian Zootechnical and Dairy Institute at Foresta di Burgos, Sardinia

As seen earlier, the basic handicap of their maternal components influences the traits appearing early in the females' life (sexual precocity, ease of first calving). A positive correlation may be presumed between the traits related to the first reproduction cycle and those concerned with later cycles. In this connexion, the greater variation appearing at a young age may provide a better assessment of the genetic variation in the adult female in the same traits (e.g. fertility), even with a small population.

Improvement of meat production from beef herds in adverse environments

The limited world feed supply and the high cost of beef production in fertile areas suited to intensification are leading to increased use of poor grazing areas (arid and mountain zones) and of the by-products of intensive cultivation by beef cattle which, with sheep and goats, are the only animals able to exploit profitably these areas and products. But it is necessary to find the best way of improving these potentials of local female populations adapted to the environments by crossing with males of beef breeds. We must also determine the possible use in such environments of crossbred females (milk X meat) from dairy herds in nearby intensive environments such as irrigated lowland areas associated with arid mountain areas, e.g. in the Mediterranean basin.

The research undertaken in cooperation with the Sardinian Zootechnical and Dairy Institute on hardy breeds of southern France and Sardinia provides useful information on this question in areas characterized by more or less prolonged undernutrition (Bibe et al., 1974; Casú et al.,1975).

When suckling cows are maintained in protected environments in which they are given feed supplements during periods of undernutrition, a two-stage crossing consisting of two successive crosses of local females with meat breed males (Charolais or Blonde) seems to be the optimum solution. Experiments on this were undertaken in southern France with the Aubrac and Gasconne breeds. In the long run this formula is more effective than upgrading the local breed to the meat breed. But when local environmental conditions cannot be changed (as in the Sardinian experiments), only a first generation crossing of local females with beef bulls will make local beef production more profitable. This is partly due to the relatively good maternal fitness of the local breeds that were exploited in the past for milk, meat and draught.

Double-muscled bulls and their female offspring have a reduced fitness and poorer adaptation which often make their use in breeding less effective in adverse environments. This also generally applies to crossbred females, i.e. offspring of dairy cows by beef bulls.

All of the results stress the importance of limiting the introduction of new genetic material in adverse beef cattle breeding environments. Preliminary studies should be undertaken to set the limits to crossing of local females with males of improved breeds. They should cover a range of environments representing present conditions as well as economically and humanly foreseeable environmental changes made by man to improve health and nutrition. As we have shown, they are likely to lead to solutions requiring the maintenance of a large sample of the local breed.

In more general terms, it is necessary to establish the interaction existing between genetic types of beef cattle and their environments. However, direct analysis of these interactions as traditionally practised (i.e. simultaneous comparison of several genetic types in several environments) requires a much too costly experimental set-up often prepared on too vague a basis. In fact a given environment represents the synthesis of disease, climatic and nutritional stress. It would be advisable to analyse thoroughly the genetic differences existing between beef cattle populations with reference to each basic type of adaptation or stress. There would then be a better understanding of the interactions discovered, and the field of application of the experimental results could be expanded. The initial work done in France and Sardinia with this approach has led to some useful conclusions:

Such tests could, if necessary, be used to improve the sampling done at present in temperate countries to select breeds and genetic types for use in crossbreeding to improve maternal performance of beef cattle in adverse environments.

Conclusions

Genetic improvement of the potential for muscular growth, which in most countries and situations seems to be regarded as the quickest way of increasing meat production and adapting such production to consumer tastes, presents considerable limitations which must be understood. In fact it is more or less closely associated, depending on the situation, with a lowering of fitness and adaptation traits of both males and females. This observation gives rise to several considerations:

References

Bibe, B., Frebling, J. & Menissier, F. 1974. Schéma d'utilisation dès races rustiques en croisement avec des races à viande. Sixième Journée du Grenier de Theix, Les troupeaux de vaches allaitantes. Bulletin technique spécial du Centre de recherches zootechniques et vétérinaires de Theix.

Bibe, B., Frebling, J., Gillard, P. & Menissier, F. 1974. Incidence de l'utilisation de taureaux culards en croisement avec des femelles de races laitières sur la production de viande de jeunes bovins. Document, First World Congress on Genetics Applied to Animal Production, Madrid, Spain, 7–11 October 1974.

Casu, S., Boyazoglu, J.G., Bibe, B. & Vissac, B. 1975. Systèmes d'amélioration génétique de la production de viande bovine dans les pays méditerranéens: les recherches sardes. Jouy-en-Josas, Centre national de recherches zootechniques, Département de génétique animale. Bulletin technique No. 22.

Centre national de recherches zootechniques. 1972. Efficacité réelle et optimum du choix des taureaux de race à viande pour le croisement industriel. Jouy-en-Josas, Centre national de recherches zootechniques. Département de génétique animale. Bulletin technique No. 15.

FAO. 1972. The relationship between milk and beef production in Europe. Rome.

Foulley, J.L. & Menissier, F. 1974. Variabilité génétique des caractères de production des femelles charolaises contrôlées en station: résultats préliminaires. Sixième Journée du Grenier de Theix. Les troupeaux de vaches allaitantes. Bulletin technique spécial du Centre de recherches zootechniques et vétérinaires de Theix.

Menissier, F., Bibe, B., Frebling, J. & Perreau, B. 1974. Premiers résultats sur les performances d'élevage des femelles Charolaises, Limousines et Maine-Anjou conduites en croisement en troupeau expérimental. Document, Journées d'étude de la Fédération européenne de zootechnie, Copenhague, Danemark.

Menissier, F., Vissac, B. & Frebling, J. 1975. Optimum breeding plans for beef cattle. Jouy-en-Josas, Centre national de recherches zootechniques, Département de génétique animale. Bulletin technique No. 21.


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