There are few reports about the slaughter and carcass characteristics of Algerian beef cattle. The fattening performance and carcass characteristics recorded in this study are specific to bulls of the local bovine population that descend of the Algerian Brown Atlas breed.
The measurement of the live weight in the context of beef cattle evaluation constitutes an essential element for the subsequent estimation setups, particularly during post-slaughtering, namely the dressing percentage, 5th quarter proportion, carcass conformation, fattening level, and the proportion of meat first-class pieces. This kind of study is also important to plan a future program of selection.
Comparing the mean live body weight of “Brune de l’Atlas” indigenous Algerian cattle (343.97 ± 93.26 kg) to that of Bos indicus indigenous African beef cattle, it appears to closely match with that of the African Zebu and Afrikaner cattle (Teye and Sunkwa 2010). It is higher than that of Nguni, Sanga and the West African shorthorn breeds, Curraleiro Pé-Duro and Pantaneiro breeds, indigenous Ethiopian cattle and Creole cattle but it is close to the weight of the young bulls resulting from the crossing of this breed with the Prim’Holstein (Teye and Sunkwa 2010; Gudeto et al 2022; Barbosa et al., 2023 ; Gelaye et al., 2022), Greek Blonde indigenous cattle of Greece (Nikolaou et al., 2023) and Nelore Brazilian cattle breed (Barbosa et al., 2023). However, the local Algerian cattle breed of these study is lower than that of Bonsmara from South Africa, N'Dama breed from Congo, American Snata Gertrudis, European Pinzgauer and Brown Swiss breeds (Strydom 2000; Silvere et al., 2023). The difference with the authors cited above might arise from several factors such as age, sex, type/breed of cattle used in each study, as well as on the general management and ecology of the area. In Algeria, previous studies reported that the live body weight varied from 250 to 350 kg (Aissaoui et al., 2003). Furthermore, relatively higher figures of mean live weight were reported by Bouzebda Afri et al (2007) using barymetric formulas. The differences within Algerian studies indicate the direct and indirect effects associated with husbandry practices, nutrition, age, cattle conformation, etc. Moreover, the high variance level of this parameter shows a high likelihood of possible production improvement of this population, which was originally never put to selection. In this regard, the live body weight represents the result of calves growth, which is meanly dependent on the milk production of the dams and secondary to the quality of forage, for which the intake increases after 3 months (Handcock et al., 2021; Gherissi et al., 2013). The empty live weight observed in this study varied from 202.52 Kg to 589.99 Kg, which indicates that a selection on this quantity parameter would be highly recommended as part of a genetic improvement in beef performance. In addition, environmental factors (temperature, humidity), rearing management conditions, low nutrient levels, and parasitism could partially improve live body weight at slaughter (Yüksel et al., 2019 ; Soulat et al., 2019).
On the other hand, the mean hot carcass weight (HCW) was 206.51 ± 51.95 kg, which was higher than that recorded on Afrikaner and Nguni African indigenous breeds but lower than that reported for the other African and Spanish young-bull rustic breeds (Strydom 2000, Albertí et al., 2005). Compared to Algerian cattle from the same population and Central African N’Dama and Zebu cattle, the HCW was close to our results (Bouzebda Afri et al. 2007; Silvere et al., 2023). Low meat production per cow could be attributed to three reasons. First, calves are fed high fibrous low quality feeds and are rarely supplemented with feed grains. Thus, their total nutritional requirements for growth are rarely met, which limits growth performance. Secondly, because of farmer needs for cash, these animals are usually sold young and thus slaughtered before approaching or achieving their genetic potential in terms of live weight (Ben Salem and Khemiri 2008). Finally the absence of selection on the autochthonous breeds plays a great role in this situation.
The average true dressing percentage (TDP) recorded in this study was 60.11±11.09%. This average is particularly high compared to that obtained in the same cattle population (Bouzebda Afri et al 2007). The difference in this result would be due to the technical means of assessment (determination of live weight by barymetric formulas), the heterogeneity of the studied animals (sex, age, fattening period), and the method of estimating carcass yield (true dressing vs. commercial dressing). On this last point, our result is estimated at 56%, which is rather close to the yield reported by Bouzebda Afri et al. (2007) and Gherissi et al., (2013). Compared to other indigenous tropical cattle populations, the true dressing percentage of the studied animals is close to that obtained in the Creole cattle population and its crossbreed with the Prim'Holstein breed (Naves 1985) and indigenous African cattle breeds (48.6% - 58.7%), but lower than that of African suckler breeds (Strydom 2000) and higher to that recorded in Zebu and N’Dama Taurine (Silvere et al., 2023). The average dressing percentage for tropical local cattle breeds can range from approximately 50% to 65%, depending on factors such as breed characteristics and management practices. Some local cattle breeds may have a higher proportion of bone, lower muscle development, or higher fat deposition compared to specialized beef breeds, which can influence dressing percentage. The trend of dressing percentages supports the previous statement that as the animal gets heavier, the dressing percentage increases.
The mean weight of the 5th quarter without including blood and stercorals was 95.24 ± 41 kg i.e. an average rate of 26% of the live weight. The following components the red offal (heart, liver, lungs, spleen and kidney), empty digestive tract, head, legs and skin weighed respectively of 15.53 ± 5.10 kg, 23±65 kg, 19.85 ± 4.33 kg, 8.45 ± 2.28 kg and 27.76 ± 7.10 kg, respectively. It is noted that the weight of red offal exceeds that reported in tropical beef cattle breeds (4,477 to 6,490 kg). The same observation is recorded for the weight of the skin (4.84 to 7.93 kg) and the weight of the digestive tract (4.56 kg to 7.41 kg) (Teye and Sunkwa 2010). Similar results were observed for the rest of the 5th quarter components. Similarly, close proportions of the 5th quarter are reported for Bonsmhara beef cattle and are a little lower compared to the other African indigenous breeds (Strydom 2000). For the moment, there is no study to discuss the variability of these parameters within the indigenous North African “Brune de l’Atlas” cattle population.
The carcass conformation refers to the physical shape, size, and muscling of a beef carcass. It is an important trait in determining the overall quality and value of the meat. It was assessed by a combination of calculated indexes and visual assessments of muscle. The mean hip thickness (HTI), carcass compactness (CCI), and buttock compactness indices were 0.34±0.05, 1.55 ± 0.37 and 0.69±0.08, respectively. These parameters are indicators of the ratio between the muscle mass and the skeletal size of the carcass. The CCI of the studied animals is similar to that of male Creole indigenous cattle breed (1.51) (Naves 1985). However, this parameter is higher than the scores obtained in the indigenous African cattle breeds (0.74 - 1.02) (Strydom 2000). A higher CCI suggests a more compact and muscular carcass, while a lower CCI indicates a less compact carcass with relatively more skeletal size. The HTI of the studied animals was higher than that shown by Naves (1985) in Creole breed (0.283). The development level of the carcass conformation in the studied animals is quite low (1.86, an average corresponding to class O on the EUROP grid). It was similar to that of Buffalo species (Nikolaou et al., 2023). This condition reflects a fairly average level of conformation with straight to concave profiles and average muscle development. Better conformation levels were observed by Alberti et al. (2010)
in Spanish beef breeds (R class). The high-priced cuts in beef cattle come from the hindquarters, the latter representing 59.22 ± 8.42% of their carcass weights in the studied animals leading to a hindquarter to forehand quarter ratio of 1.28±0.11. This result is better than that reported by Naves (1985) and Teye and Sunkwa (2010): 47.7% and 46.3%, respectively, but lower than those obtained in African Bonsmara-crossbred (Slabbert et al., 1992). Naves (1985) found more representativeness of the forehand quarters in the carcass compared to the hindquarters in male Creole breed and tropical beef cattle breeds. In this case, it is important to point out the differences that can exert anatomical particularities in certain tropical breeds with excessive development of hump on the forehandquarter and consequently the imbalance in the rate that the fore and the hindquarters represent in the carcass. The studied animals “Brune de l’Atlas” are considered the rustic breed of North Africa. They are often characterized by their hardiness, adaptability to harsh environments, and ability to thrive on limited resources and they are not typically selected for intensive meat production or specific carcass traits. The variability of carcass conformation would be related to several factors, including genetics, breed, age, nutrition, management practices, and environmental influences. Specific indices and conformation levels may vary depending on breed, production system, and market preferences. Farmers and breeders often refer to breed-specific standards and guidelines to assess and select animals with desirable hip thickness indices for breeding or marketing purposes.
On the other hand, the studied cattle express an average score of low fattening status of 1.85 ± 0.83, i.e. carcasses with a light cover of fat and muscles almost everywhere apparent. Within the thoracic cavity, the muscle was clearly visible between the ribs. Compared to other cattle populations, a similar fattening state is observed in Spanish beef breeds, particularly in young bulls with low commercial weight (Alberti et al., 2010). These results are supported by the mean body fat weight, which is 12.20 ± 9.09 Kg, and an average fat index (FI) of 14.81 ± 7.67. Similar results were reported for the Creole breed. In the studied samples by Guillaume (2006) in the PrimHolstein and Charolais breed, 22% of the carcasses are considered too fat (classified as 4) in the first breed and only 4.3% in the second breed. These carcasses come from animals slaughtered at 387.5 kg for young PrimHolstein cattle and 437 kg in Charolais bulls. Our results showed a low ability to store energetic tissues depending on low slaughter weight and low carcass weight. Otherwise, the early development of body fat, which generally increases at low carcass weight, requires slaughter at low body weight to avoid excessive fat deposition on the carcass. Regarding the carcass quality, this low fat deposit could be an advantage, as it is possible to seek higher slaughter weights without ending up in a state of excessive and early fattening since the local market requests light to medium carcasses. However, consideration must also be given to the complex interaction of multiple factors in carcass fattening variability, and their relative importance can vary depending on the specific production system, breed, and environmental conditions (Yüksel et al., 2019 ; Soulat et al., 2019). Producers and feedlot operators often strive to manage these factors to optimize carcass quality, consistency, and marketability (Soulat et al., 2019). It's important to note that while there are breed standards and guidelines for desirable carcass conformation and fattening levels, there is inherent variability within any beef cattle population. This variation allows for genetic diversity and the potential for improvement through selective breeding programs (Barro et al., 2023; Mamede et al., 2023). Additionally, consumer preferences and market demands may influence the perceived value of different carcass conformations and fattening, resulting in variations in desirability depending on the specific market or end-use of the meat.
The muscular fitness of beef cattle refers to the development and distribution of muscle throughout the animal's body. Cattle with adequate muscling typically have a higher muscle-to-bone ratio and exhibit strong muscle definition in areas such as the hindquarters and loin. Low body and carcass fitness with high variance in these parameters were observed in the studied cattle population. Achieving carcass fitness involves genetic selection, appropriate nutrition, proper management practices, and adherence to industry standards and grading systems. The specific criteria for carcass fitness can vary depending on regional preferences, breed characteristics, and market demands. Producers and processors aim to produce and select cattle that consistently yield carcasses that meet the desired fitness criteria for their target markets. The frame size is also an interesting parameter to evaluation conformation and fitness of beef cattle and is has the potential to be used as a parameter in the selection of precocious beef cattle (Barro et al., 2023).
The carcass characteristics, particularly carcass weight and conformation, showed rather modest meat traits in the local Algerian cattle population, which has never been subjected to a reasoned selection program within the framework of the genetic improvement of meat production performance. Recent studies showed that yearling weight, visual scores of body structure, muscularity, and precocity, fattening and conformation carcass traits have moderate to high heritability (Barro et al., 2023; Mamede et al., 2023) with significant genetic correlation between body weight (BW) at slaughter on carcass and meat quality (Albertí et al., 2005). Thus, the high variance level for most of the studied parameters, explaining the heterogeneity of individuals in the local cattle population, which would make it easier to undertake a selection program to improve bulls economic value. It also important to point out the elaborated positive linear correlations between body weight and carcass weight, 5th quarter and carcass conformation and negatively correlation with slaughter yield and body fitness.