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The Breed  ► INTRODUCTION TO THE BREED   [ KLIEK HIER VIR DIE AFRIKAANSE WEERGAWE ]
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Two conformation types of the Afrikaner Cattle breed, i.e. cylindrical and flat, were compared with reference to growth performance, and carcass and meat properties.

At the beginning of the test the two types were distinguished merely by visual appraisal. The legitimacy of such a distinction will be discussed.

The test procedures were discussed with the Breed Society before the commencement of the experiment and involved the following:

• Thirty-six Afrikaner weaners, 18 of each of the two types respectively were randomly arranged in 4 groups of 5 animals each (reference group = 3 animals). With the exception of the reference groups that were slaughtered at the beginning of the test, the animals were kept under intensive feeding conditions and slaughtered at 300, 340 and 380 kg respectively. Growth rate and feed efficiency were measured during the growth period.

• With the attainment of the specified slaughter masses the animals were slaughtered in the specified slaughtering groups and all the slaughter data (masses of all parts of the fifth quarter and the carcass mass) and carcass data (carcass measurements and carcass tissue masses) were noted. Certain samples were taken and the total carcass composition and tissue distribution were calculated.

• Samples taken immediately after slaughtering and at the time of carcass processing were evaluated in order to describe the meat quality traits of every animal.

  Since the animals were slaughtered at different slaughtering masses and thus at different stages of carcass maturity, an attempt was made to compare the different qualities on the same stage of carcass maturity. Therefore a co-variation analysis was used and subcutaneous fat was used as co-variant if it showed a statistically significant effect on the quality that was measured. This means that, although these animals were slaughtered at different slaughtering masses (and therefore fatness and carcass maturity), the comparison was made between the two different conformation types in the same subcutaneous fat class, is similar to the classification system. If the comparison had been made with respect to the same slaughtering mass or days on feed, the later maturity types would have benefited. With subcutaneous fat as co-variant an attempt was made to compare animals at the same stage of carcass maturity.

GROWTH PERFORMANCE

Averages for growth performance are presented in Table 1. Neither carcass fatness nor number of days fed had any significant effect on the growth performance of the two groups. On average, T-2 took longer to reach the different target masses, but this is due to the fact that their starting mass was lower than that of the T-1 group. Group T-2 was also fatter at the beginning of the test, which indicates that this group is possibly an earlier maturity type than T-1. This point will be discussed in more detail later in this document.

TABLE 1 - AVERAGES OF GROWTH QUALITIES OF TWO AFRIKANER TYPES

SLAUGHTER AND CARCASS QUALITIES:

All slaughter and carcass qualities are indicated in Table 2 and 3 respectively. Unless otherwise indicated, the two types are compared with each other at constant subcutaneous fat. (% subcutaneous fat = 4,9 % i.e. Fat Code = 2+)

TABLE 2: AVERAGES FOR SLAUGHTER ANIMAL QUALITIES OF TWO AFRIKANER TYPES. SUBCUTANEOUS FAT % = 4,9%

In spite of the large numeric differences in slaughter mass, carcass mass and slaughtering percentage, these differences were not statistically significant. The probable reason for this is the large variation in these qualities within the types (i.e. that the variation around the averages is large). There is a tendency for T-1 to yield a higher carcass mass than T-2 (at a higher slaughter percentage) at the same carcass fatness (subcutaneous fat = 4,9 %). This higher slaughtering mass (the same fatness) indicates a later carcass maturity for T-1 with respect to T-2. According to De Bruyn (1991) the difference in slaughtering percentage can be ascribed to the difference in slaughtering mass, since slaughtering percentage is largely mass and fat dependent.  The comparisons were done at the same fatness and therefore slaughtering percentage is mass dependent. The one percent difference in slaughtering percentage is equal to approximately 3 kilograms carcass mass.

According to Table 3 there were no significant differences in carcass properties between the two types. The % bone and meat tended to be respectively higher and lower in T-2 carcasses compared to T-1 carcasses. As already mentioned, the starting mass and carcass mass of T-1 also tended to be higher than that of T-2, which is an indication that T-1 was a later maturity group of animals. By maturity we mean that animals of the T-1 group will have reached a higher carcass mass at marketability (e.g. Fat Code 2) than animals of the T-2 group. According to De Bruyn (1991) carcasses of later maturity types proportionally have more meat and less bone at the same subcutaneous fat than earlier maturity types, which is demonstrated in this test. Meat is defined as the amount of muscle, intermuscular fat and intramuscular fat. According to the different fat parameters (omentum fat, kidney fat, carcass fat and marbling) T-1 had only one meaningful difference from T-2 and that is where kidney fat is concerned, while the other fat parameters also indicated that T-1 had more intramuscular fat (marbling), omentum fat and total carcass fat. These differences were however not significant.

a,b Averages in the same row with different headings, meaningful difference (P<0,05)
 

In respect of the distribution of meat over the different cuts of the carcass, it may be noted that on average 44% of the total meat occurred in more expensive cuts in the hindquarter and sirloins. The remaining 54% was distributed as follows: 31% in the cheaper cuts of the rib, neck and shoulder, 19% in the flank and brisket and 6% in the shin cuts. There was no meaningful difference in tissue distribution (meat) between the two types. The apparent difference in carcass maturity between the two groups may be interpreted as follows. The fact that the starting mass of T-2 was on average lower than that of T-1 can simply mean that this group of animals weaned lighter. Furthermore, according to research that was done on maturity types (unpublished), it would mean that at the same mass in the growth phase, (e.g. 300 kg) T-1 animals would deposit more fat than T-2 that was at a higher mass when feeding commenced. The % of subcutaneous fat also differed between T-1 and T-2 (4,2 vs. 5,0%). With this argument it is implied that animals that started at a lower mass, will deposit fat earlier than the same type of animals who started at a higher mass. One cannot say with certainty that there were maturity type differences between the 2 groups just because the one group weighed less than the other one when they started the tests, because the pre-wean circumstances of the 2 groups might not necessarily have been the same.

MEAT QUALITY TRAITS:  AVERAGES FOR MEAT QUALITY TRAITS ARE INDICATED IN TABLE 4

a, b, c, d Averages in different numbers in heading – differ significantly (P<0.05)

According to sensory judging, there was no significant difference in the different traits between the two types. The two physical measurements of meat tenderness indicate that the meat of T-1 tended to be tenderer than that of T-2. The same muscle is used for both methods (M. Iongissimus thoracis). The sensory sample is prepared by means of a dry heat method in an oven at a constant temperature, while the other sample is heated in a PVC bag in water (70 degrees C). However, the averages obtained by both methods were not significantly different. The biochemical and histological properties of the muscle mentioned above differed slightly, but once again the difference was not significant. The aging potential, measured according to the miofribrillar fragmentation index, tended to be higher in T-1 after 1,7 and 14-day periods. According to this measurement the meat of T-1 has a 5% higher potential to tenderise in the maturing process than that of T-2. The histological description of muscle tissue properties, i.e. relationship and size of white intermediate and red-muscle tissue was different between the two types. The relevant muscle of the T-1 had more red tissue (6%) and less white tissue (7%) (P<0,05) than that of the T-2 group. Furthermore, the size of the white tissue was 10% smaller in T-1. According to Dreyer et al. (1977) and Calkins et al. (1981) meat tenderness is correlated negatively with white tissue size and amount. On the grounds of biochemical properties it could be therefore expected that the meat of T-1 should be tenderer than that of T-2.

The fact that, in spite of more biochemical and histological differences, there was no significant difference in meat tenderness between the two groups is proof that meat tenderness is influenced by a variety of factors. These can include breed, type of animal, but also several environmental effects (treatment during and after slaughtering). Therefore the effect of the differences in biochemical and histological properties was probably not large enough to induce differences in tenderness.

BETWEEN BREED COMPARISONS

SLAUGHTER ANIMAL CHARACTERISTICS

The carcass and carcass quality traits of different breeds, tested under the same conditions, will now be discussed. The aim of this discussion is not to compare the Afrikaner with other, mainly later maturity breeds with regards to performance characteristics, but to indicate that different breeds each excel on their own territory.

TABLE 5:  CARCASS QUALITIES OF THE AFRIKANER AND 4 OTHER BREEDS OF DIFFERENT MATURITY TYPES (COMPARISON AT CONSTANT SUBCUTANEOUS FAT % – 4,7%)

a, b, c, d Averages of figures denoted by subscripts vary significantly (P<0,05)

As is generally known, the Afrikaner is considered to be an early-maturity breed (carcass maturity). This is confirmed in Table 5, i.e. that the carcass masses at the same subcutaneous fat % of the Afrikaner were significantly lower than that of other breeds. Because of end mass differences the Afrikaner also slaughtered out meaningfully (P<0,05) less than other breeds. According to De Bruyn (1991) slaughtering percentage is primarily mass and fat dependent. Seeing that the present data was tested at constant fatness, the lower mass of the Afrikaner would imply a lower slaughter percentage. Specific breed effects also occur. De Bruyn (1991) found that the Charolais and Brahman yielded slightly higher slaughter percentages, due to respectively a low hide mass and a low-digestion canal mass.

CARCASS COMPOSITION:

From Table 5 it could be deduced that the Afrikaner has the poorest meat conformation of the breeds concerned, on grounds of significant difference (P>0,05) in carcass and buttock compactness between the Afrikaner and the other breeds. These differences mean that the 4 other breeds (especially Breed 4) have significantly more mass per carcass length than the Afrikaner. Carcass mass, however, comprises bone, meat and fat. If the true edible yield, i.e. meat-to-bone or muscle-to-bone relationships are considered, the Afrikaner performed significantly better than Breed 3 which is a later maturity breed with higher carcass compactness than the Afrikaner. Furthermore only Breed 1 had significantly higher meat to bone relationship than the Afrikaner. The poor performance of Breed 3 can be ascribed to the high bone yield. Thus, the following conclusions can be drawn:

1. Conformation is not a good yardstick for predicting meat yield in a live animal or carcass

2. When the true meat outturn is considered, breeds that are relatively early maturing, and often show a weaker conformation do not necessarily perform poorer than later-maturity breeds. This, on its own, emphasises the importance of real measurements of edible outturns and the importance of finding accurate measuring rods that can predict meat outcome on living animals.

3. Meat-to-bone ratio increases with an increase in carcass maturity, in other words, breeds or types that produce a high carcass mass at constant fatness will generally produce more meat per bone unit than earlier-maturity types (De Bruyn, 1991). It is, however, possible that specific breed effects may occur, in other words, that earlier-maturity types or breeds may compare well with regards to meat yield per bone unit against other breeds. Another important aspect that stands out in Table 5 is the low carcass fat yield of the Afrikaner, especially relative to Breeds 2, 3 and 4.

4. This fat parameter measures all fat in the carcass, namely subcutaneous fat (which is constant: 4,7%), intramuscular fat (marbling) and intermuscular fat. Considering that the subcutaneous fat is constant, it means that the Afrikaner produces less intra-muscular and intermuscular fat in the same carcass fat code than the other breeds. If the carcass should thus be cut up, the carcass of the Afrikaner will produce a higher edible yield than that of Breeds 2–4, seeing that less fat occurs between muscles. It is also interesting to note that the carcass of the Afrikaner carries relatively more mass in the more expensive cuts in the hindquarter, and that there is relatively more meat as a percentage of the total carcass in these cuts than is the case in other breeds.

NB – In summary, it can be said that although the Afrikaner is an early-maturity breed and therefore not so advantageous with reference to carcass mass increase or final carcass mass for the secondary producer (feedlot), the breed compares favourably with the other larger-frame breeds which have already been tested in the Genotype Evaluation Programme. Where crossbreeding is concerned these characteristics of the Afrikaner can be used to good effect in combination with later-maturity breeds or types.

TABLE 6: MEAT QUALITY CHARACTERISTICS OF THE AFRIKANER AND 4 OTHER BREEDS OF DIFFERENT MATURITY TYPES (COMPARISON AT CONSTANT SUBCUTANEOUS FATt % = 4,7%)

a, b, c, d Averages with different numbers in heading significant difference (P<0,05)

The meat quality characteristics of the Afrikaner and 4 other breeds are indicated in Table 6.

From these results it is clear that the Afrikaner meat tested the tenderest of all the breeds that have been tested in the Genotype Evaluation Programme up till now.

Both the sensory characteristics for tenderness indicate this advantage, while the mechanical measurement of tenderness (cut resistance) confirms it. This does not imply that the meat of other breeds is tough, since cut resistance measurements of <110N may be considered as acceptable. Only Breed 3 exceeds this level where cut resistance is concerned. The sensory evaluations of Breed 3, however, showed that the meat of this breed compares well to the other breeds.

The advantage that the Afrikaner enjoys above all the other breeds can probably be explained in terms of histological and biochemical characteristics. Firstly the maturation potential of the Afrikaner was respectively 12 and 31% higher than that of Breed 1 and 4 respectively. It can thus be deduced that the Afrikaner probably has a higher intrinsic ability with reference to the enzyme system that tenderises meat during the maturation process. Currently, more intensive research regarding this subject is being done with several breeds, since according to the literature the meat tenderness of Sanga types compares favourably with British breeds, while the meat tenderness of certain Indicus breeds is less advantageous. That is why the mechanisms that promote meat tenderness evoke so much interest worldwide, as a result of this contrast between Sanga and Indicus breeds.

The histological characteristics of the Afrikaner also differed from that of other breeds. The percentage red muscle fibres and intermediate fibres of the Afrikaner is respectively 6 and 18% higher than that of Breed 1, while the white muscle fibres are 20% lower than that of Breed 1. According to Dreyer et al. (1977) and Calkins et al. (1981) meat tenderness was correlated negatively with white fibre size and number. Therefore the Afrikaner is also in an advantageous position where these characteristics are concerned.

The connective tissue characteristics (collagen) weren’t available at the time of the statistical analysis and will be presented as an addendum to this report as soon as possible. The quality of meat is dependent upon a great number of characteristics, which are linked to the animal, but also to environmental effects. Since environmental effects were kept constant during these experiments, the differences between breeds can be attributed largely to intrinsic characteristics and therefore hereditary characteristics. The full spectrum of characteristics that influence meat quality is not described, but according to known results, the Afrikaner performs very favourably in comparison to other tested breeds.

SUMMARY AND CONCLUSION

1. The selection of conformation types on a visual basis had no significant effect on the production and production characteristics of the Afrikaner cattle used in this test. The visual distinction between cylindrical and flat conformation merely indicated the following tendencies:

2. Animals with a better conformation tended towards later carcass maturity, i.e., produced a higher carcass mass at the same fat code. These animals tended to slaughter out higher % than animals with a poorer conformation. The carcasses of these animals had a tendency towards a better meat to bone relationship, but also to a higher total carcass fat content at a constant fat code. Animals with a better visual conformation tended to produce more tender meat, due amongst others, to better maturity ability.

3. Breeds which are later maturing (higher carcass mass at constant fat code) compared as follows with the Afrikaner:

The slaughter percentage of these breeds tended to be higher (sometimes significantly) than that of the Afrikaner. It is confirmed in the comparison that slaughter percentage is mass dependent; in other words, breeds with higher final masses (steady fatness) generally yield higher slaughter percentages.

The later-maturity breeds had a better carcass and hindquarter conformation than the Afrikaner. In contrast, there was no significant difference in the muscle-to-bone relationship between these breeds and the Afrikaner. Furthermore, the total carcass fat of the Afrikaner was significantly lower than those of some of the later maturity types, while the relative meat and cut yield of the more expensive cuts of the hindquarter were significantly higher in the Afrikaner. Although several production characteristics, such as growth rate and efficiency, final carcass mass and slaughter percentage of the Afrikaner aren’t necessarily as advantageous as in larger, later-maturity breeds, the Afrikaner compares favourably with later-maturity breeds with regard to edible yields.

The meat tenderness of the Afrikaner compared extremely well against breeds that have already been tested in the Genotype Evaluation Programme. This advantage can be ascribed to the good maturation potential and muscle fibre characteristics of the Afrikaner. According to De Bruyn (1991), the Afrikaner also compared extremely favourably with the European Hereford, Charolais and Simmentaler and performed significantly better than the Brahman.

From these results it is clear that the Afrikaner meat tested the tenderest of all breeds that have been tested in the Genotype Evaluation program up till now.

Sources:

DE BRUYN, JF. Production and product characteristics of different cattle genotypes under feedlot conditions. D.Sc. Thesis, University of Pretoria.

DREYER, JH, NAUDÉ, RT, HENNING, JWN & ROSSOUW, EJ. 1977. The influence of breed, castration and age on muscle-fibre type diameter in Friesland and Afrikaner cattle. SA Journal of Animal Sciences 7(171).

CALKINS, CR, DUTSON, TR, SMITH, GG, CARPENTER, ZL & DAVIS, GW. 1981. Relationship of fibre type composition to marbling and tenderness of bovine muscle. Journal of Food Sciences 46(708).
       

                
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