Pág. , En: Bovinocultura de Corte. Alexandre Vaz Pires(1º edição), FEALQ- Piracicaba-SP, Brasil. FLAMENBAUM I, GALON N. Management of. Eficiencia da vaca de cria. In: Alexandre Vaz Pires. (Org.). Bovinocultura de Corte . Piracicaba- SP: FEALQ, , v. 1, p. Bovinocultura de Corte. 1ed. Eler, J.P.; Ferraz, J.B.S.; Teixeira, L.A. Seleção para precocidade sexual em novilhas de corte. In Bovinocultura de Corte, (Alexandre Vaz Pires, Editor). v II.
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Abstract This study aimed to evaluate the effects of the genetic group, maturity, and fatness score of cattle on losses by bruises and final pH value of the carcass of steers and cows. The number of bruises and the final pH value of the carcasses were evaluated as response variables in function of the genetic group, the physiological maturity, and the fatness score.
The carcasses with moderate fat showed a pirez number of bruises than scarce-fat carcasses only in males.
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Bruises increased by As regards the pH values, there were variations between sexes, with females having, on average, higher pH, which differed between zebu and bovinoculturw cattle. Two-teethed males displayed higher pH values than four-teethed animals, while four and six-teethed females presented higher values than the others.
Physiological maturity, fatness score, and genetic group influence losses by bruises in bovine carcasses, with older animals being more susceptible to bruises. Zebu animals being are also more susceptible. Females are more susceptible to final pH alterations in the carcass, mainly in the carcasses of zebu animals. Brazil has a prominent place in the world scenario as a big producer and exporter of beef, with considerable increases in the amounts consumed in the internal market and exports.
The females have a fundamental relative importance of representing The growing consumption of meat resulting from the increasing number of developing countries, or even as a consequence of the better income pirse populations, generates great concern about the quality and certification of these products. Animal protein consumers demand better production conditions that are sustainable and that reduce animal suffering, associating quality with animal welfare and food safety 2.
Together, these factors induce the production of carcasses of better quality, better reproductive rates, and better productive responses, with consequent economic gains 3. The pre-slaughter stress caused by inadequate management and transport conditions increases losses by bruises on the animal 5as well as an improper transformation of muscle into meat, reducing the product quality and its shelf life at retailers 6. Animals under stress have physiological mechanisms of adaptation to adverse conditions 7 ; however, the energy cost of these mechanisms may result in the partial or total absence of muscle glycogen, leading to a decrease in the formation of lactic acid and rapid establishment of the rigor mortis.
For Lawrie 8the combination of these events modifies the standard conversion of muscle into meat, making the meat tougher and darker — the so-called DFD dark, firm, dry meat. Stressful situations intensify according to sex 9species, breed, and bloodline 10,11 ; category and age 12 ; body size, anatomical conditions and fatness 13,14 ; and transport and finishing system 15,5.
Thus, reducing the animal stress is a measure of great importance because, in addition to losses in meat quality, stressed animals are more prone to physical injuries, piress consequent economic losses.
The present study aimed to evaluate the genetic group, maturity, and fatness score of males and females on losses by bruises and final pH value measured 24 h after slaughter. The dataset consisted of the record of 2, carcasses of cattle slaughtered between August and November in a meat-packing plant under federal inspection S.
We used in this study carcasses from castrated steers 1, and female 1, cattle originating from the purchase of the company for slaughter and industrialization. Animals came corfe several regions and were transported through different pries of vehicles, roads, topographies, and distances; thus, they represented the most diversified production systems and characterized the cattle marketing.
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Carcasses of steers and culling cows from the herds were used in this study. Cows were culled due to advanced age, reproductive problems or they were considered a surplus from herd replacement, having a similar market value to steers.
Upon being unloaded at the packing plant, animals were housed in separated corrals according to their origin and divided by sex. Also at unloading, the genetic group of the animals was evaluated, and cattle were classified as taurine and zebu cattle. Taurine animals have a predominance of animals from the batches with European phenotypic characteristics, compact muscle mass, strong bone structure, thick piress, small dewlap, long hair, a strong head with medium length chamfer, medium-sized ears, long and arched ribs, and either the presence or the absence of horns.
Zebu cattle had the predominance of animals from the batches with zebu phenotypic characteristics, hump, short and fine hair, dark skin, a head shaped like a coffin, medium to long ears, straight chamfer, black and bovincultura nose, either the presence or the absence of horns, and a large dewlap starting below the jaw and ending at the navel.
Animals followed the logistics vaa the packing-plant slaughter line. After the hide had been removed, all carcasses were identified individually according to the sequential number of the slaughter order, which at that moment became the identification reference of each carcass.
This identification allowed to later relate the pH and bruising data dependent variables to the data provided by the carcass classification system. These bovnocultura refer to the following independent variables: Injuries or bruises on the carcasses were quantified by counting them on the slaughter line immediately after the hide had been removed from the animals; values were recorded on spreadsheets according to the numerical sequence of the carcasses.
Animal maturity was evaluated by dentition, after the heads were removed from the carcasses, and classified as: Fatness score was evaluated by technicians from the company and from pures associations, maintaining the patterns established by Ordinance No.
The final pH of the carcasses was measured 24 h after slaughter, on the longissimus dorsi muscle at a depth of four centimeters.
This measurement was obtained using a portable digital pH meter ASKO SX calibrated according to the specifications; an average value was calculated between both half-carcasses. The total pre-slaughter fasting time transport time and rest in the slaughterhouse pens were baz as covariates in the crote. Analyses were performed separately for males and females, according to the following model:. Analyses were performed separately for males and females, and data bovinocultkra presented by sex as a function of the independent variables Table 1.
Analyzing the overall results, females had Of the 2, carcasses evaluated, carcasses of males and of females did not have any bruises, representing This finding demonstrates the greater susceptibility of females to get bruised in the pre-slaughter period.
The analysis of the mean values for bruises on the carcasses revealed that both sexes displayed an increase accompanying the maturity advance, with no significant differences from deciduous teeth up to four bovincoultura and up to two teeth, for males and females, respectively.
These increases in relation to sex and the advancement in maturity are probably because females and older animals are more reactive to adversity and new situations when boarding the vehicle, during transport, and at unloading 18as well as the greater presence of horns, which causes bruising on animals According to Vaz et al. Many studies have reported a greater incidence of injuries in females compared with males. Grandin 20 mentioned that the higher prevalence of injuries in females is due to the reproductive management to which cows are subjected on farms; it may also be due to their larger weight and body size In the present study, carcasses with a fat score absent or excessive were not observed, probably because of the purchasing criterion of the industry, which avoids the acquisition of animals with absent or excess fat because they do not present good quality carcass.
However, males presented a difference between the moderate and scarce fatness classes, which did not differ from the others. The higher number of animals with adequate fatness moderate can be explained in part by the larger number of carcasses evaluated, as they are the objective of industrial purchase Simarly, the high number of bruises is due to the conformation of the animals, that present a higher fatness degree and have less space in vehicles and corrals, being more prone to being hit.
Evaluating 15, carcasses of Nellore crossbred animals in Minas Gerais State and investigating the probable causative agents of bruises, Silva et al. The genetic group showed About carcass bruising, among the many causative factors, the genetic group has an influence on their occurrence, with animals with zebu phenotypes having greater changes of bruising due to their reactivity to adversities from management and facilities.
For Delgado and Santos 23the biological type of the animal defined by the breed characteristics or by breeds that are in its genetic composition is the key point of management and is decisive to the final quality of the meat product. The relative analysis of the mean values showed greater amplitudes wlexandre males, whereas in females, despite the lower variation, absolute numbers are higher and with less dispersion, and they have more bruises when compared with males.
Regardless of the category or age of the animals, Civeira et al. The pH values, measured after 24 h of chilling, were lower than 5. Although the meat quality cote as cattle grow older due to changes in muscle composition and metabolic characteristics 26in this study the pH measurements in both genders did not increase or decrease accompanying the maturity of animals. The pH decline increases as the animals age, but final pH values remain very similar In males, the highest pH values were observed in two-teethed animals 5.
In females with four and six teeth, pH values were higher than in the other maturities. Older animals were expected to show higher pH values, since they are alexandree more reactive than younger animals, depleting their muscle glycogen reserves faster.
Although the statistical analysis did not compare males and females, on the average of the different maturities, females 5. Bovjnocultura with zebu females divided into eight groups, Leite et al. Variations in pH alexandrw related to pre-slaughter stress, and more marked differences are observed on animals with different sexual conditions 8under different pre-slaughter managements, or from different genetic groups, which ce in turn alter the stress status prior to stunning The breed characterization showed pH values within the ideal range below 5.
Physiological maturity, fatness score, and genetic group are factors responsible for losses by bruises and final pH value in cattle carcasses. Factors influencing the occurrence of bruises corfe alterations in the final pH of carcasses act aleaxndre in males and females. While physiological maturity acts independently of the sex, with older animals bruising more often, the fatness score influences only males, with a higher number of bruises on carcass with moderate fat scores.
Aoexandre should be stressed that although the pH values were within the ideal range for beef exports, females showed greater susceptibility to qualitative alterations in pH in zebu carcasses in relation to the taurine breeds, which was not observed in males. Regardless of boinocultura characteristics evaluated, females appeared to be more susceptible to losses by bruises and variation in the final pH value.
Have we underestimated the impact of pre-slaughter stress on meat quality in ruminants?.
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Assessment of stress during handling and transport. Journal of Animal Science. Comportamento de bovinos de corte em pista de remate. Revista Bovinoccultura de Zootecnia. Factors affecting body weight loss during commercial long haul transport of cattle in North America. Effects of loading behaviour and road transport stress on traumatic injuries in cattle transported by road during the hot-dry season.
Risk factors influencing bruising and high muscle pH in Colombian cattle carcasses due to transport and pre-slaughter operations. Behavioural principles of handling cattle and other grazing animals under extensive conditions.
Grandin T EdLivestock handling and transport. Feedlot cattle with calm temperaments have higher average daily gains than cattle with excitable temperaments. Journal of animal science. American International Journal of Contemporary Research. C Fatores anteriores e posteriores ao abate que influenciam a qualidade de carne. Pre-slaughtering factors related to bruises on cattle carcasses. Animal Production Science [Internet].