Increasing Slaughter Age Research Articles

Pathomorphological and Meat Quality Alterations Connected with Wooden Breast in Broiler Chickens of Different Genotypes and Slaughter Ages

Abstract This study examined pathomorphological changes and meat quality alterations associated with Wooden Breast Myopathy (WB) in total of 192 broiler chickens divided into Ross 308 (n=96) and Cobb 500 (n=96) heavy hybrids at ages 42, 60, and 70 days. WB occurrence remained consistently high (>73%) across periods, peaking on day 70 (83% for Ross, 90% for Cobb). Cobb broilers had better production results and carcass traits parameters after day 42 and day 60 of the experiment (p≤0.05). Genotype did not affect WB occurrence or severity, while slaughter age influenced severe cases WB occurrence, increasing from 11.67% on day 42 to 36.67% on day 70 (p=0.003). The presence of WB was associated with higher ultimate pH, lightness (L*), redness (a*), and yellowness (b*) of the muscle (p<0.0001), except on day 70. Physicochemical and color parameters were also influenced by slaughter age (p<0.0001). On day 42, drip loss (p<0.0001), cooking loss (p≤0.05) and shear force (p<0.0001) were affected by genotype. On days 60 and 70, the differences in water retention capacity were observed only between normal and severely affected breasts (p<0.0001). For each slaughter age severely affected WB had higher shear force compared to normal breasts (p<0.0001). Additionally, with the increasing slaughter age of broilers, drip loss, cooking loss, and shear force of the breast meat were increased (p<0.0001). The results obtained regarding the occurrence and severity of WB and its consequent meat quality alterations suggest that extended fattening is not recommended for poultry production.

Effects of in ovo vaccination time on broiler performance parameters under field conditions

Hatchery performance is often evaluated based on descriptors such as hatchability, 7-d mortality, and cost. In addition to these descriptors, it is useful to include in this analysis aspects of chick quality through post-hatch performance. Realizing the bird's complete genetic potential necessitates meeting various criteria, with effective support for the chick's immune system being among the pivotal factors. To be effective, in ovo vaccination systems must deliver the vaccines to specific sites in the egg, a circumstance that directly depends on when the injection is made. We examined production data to evaluate the impact of in ovo vaccination time on performance parameters of male Ross308AP chicks. A comprehensive survey was conducted examining records from 3,722 broiler flocks produced and raised by the same company under standard nutrition and management conditions. The selected data specifically pertained to flocks that underwent slaughter between 41 and 45 d. In our analysis, 4 different linear models were built, one for each response variable: mean weight (MW), body weight gain (BWG), corrected feeding conversion rate (cFCR), and total mortality (TM). The linear models used in the analyses included as main predictor the timing of in ovo vaccination (440, 444, 448, 452, 456, 458, and 460 h of incubation), and as additional predictors: age of the breeding flock (26-35, 36-55 and 56-66 wks old), slaughter age, identity of the hatchery, and the season at which the data was collected. Our results showed that the timing of in ovo vaccination significantly affected BWG and cFCR, with procedures performed at 460 h of incubation showing the best outcomes. Breeding flock age affected all response variables, with older breeding flocks delivering increased MW, BWG and TM, and middle-aged flocks increased cFCR. Increasing slaughter age reduced BWG while MW, cFCR and TM were all increased. These data emphasize the benefits of performing in ovo vaccination as close as possible to 460 h of incubation to extract the best BWG and cFCR from Ross308AP male broiler.

Does slaughter age affect amino acids and fatty acids profiles and health and nutritional values of male and female ROSS 308 broiler chicken breast muscle?

Chemical composition, amino acids (AAs), and fatty acid (FAs) profiles, and health and nutrition values of breast muscle of ROSS 308 broiler chickens were studied after being slaughtered at 28, 35, 42, and 49 d of age (n=126 males and 126 females/slaughter age). The slaughter age significantly affected some AAs levels including glutamic acid, valine, isoleucine, histidine, and leucine, and some FAs level including capric acid, tetradecanoic acid, eicosanoic acid, total saturated fatty acids, 9-pentadecenoic acid, hexadecatetraenoic acid, α-linolenic acid, stearidonic acid, linoleic acid, dihomo-γ-linolenic acid, arachidonic acid, adrenic acid, omega 6, sum polyunsaturated fatty acids (Ʃ PUFAs), and unsaturation index. Subsequently, the slaughter age significantly affected some health indexes including the n-6/n-3 ratio, thrombogenic index, hypocholesterolemic/hypercholesterolemic ratio, and health-promoting index. Valine, leucine, isoleucine, histidine, and glutamic acid levels increased with increasing slaughter age until 35 d of age and then decreased with increasing slaughter age until 49 d of age. Moreover, the health indices of fatty acids were best at slaughter age of 35 d, followed by 49 d, and the lowest health-promoting indices were at 42 d, followed by 28 d. The sex did not affect (P ˃ 0.05) all the evaluating parameters including chemical composition, amino acid and fatty acid profiles, and related health indices. There was no significant interaction effect between sex and slaughter age in all evaluating parameters except in stearidonic acid level. In conclusion, amino acids and fatty acids profiles and health and nutritional values of male and female ROSS 308 broiler chicken breast muscle can be affected by slaughter age. The study provides valuable insights into the nutritional value of meat, including its composition, amino acid, and fatty acid profiles, and associated health indices, for both male and female fast-growing ROSS 308 broiler chickens, as the slaughter age increases.

Physicochemical Properties of Black Korean Goat Meat with Various Slaughter Ages

This study was conducted to analyze the physicochemical properties of black goat meat according to the slaughter age (3, 6, 9, 12, 24, 36 months). The moisture content tended to decrease, whereas the fat content, pH, and free amino acid composition tended to increase with increasing slaughter age. The collagen content increased significantly with the increasing slaughter age (p < 0.05). The cooking yield showed a tendency to increase up to 12 months of age, and there was no significant difference after 12 months of age. In all mineral contents, the sample for 12 months of age showed higher values than the others. Considering fatty acid composition, the saturated fatty acid content of the 12-month sample had a lower value than the other samples. However, the unsaturated fatty acid of the 12-month sample had higher values than the other samples. Therefore, the best slaughter age for black goats occurs at 12 months of age when nutrition is excellent.

Parâmetros de produção e qualidade da carne de frangos Label Rouge em diferentes idades de abate

ABSTRACT: This study evaluated the performance parameters, carcass characteristics, and meat quality of Label Rouge chickens raised under an alternative system as a function of age at slaughter. The design was completely randomized with a 5×2 factorial arrangement, with slaughtering at five ages (70, 90, 120, 150, and 180 days) and two sexes. A total of 240 birds (Pescoço Pelado strain) were used, including 120 females and 120 males. Performance, carcass, physicochemical, proximate composition, and muscle fiber traits were evaluated. Rearing time and sex had significant effects on performance-related traits, with better results for males. The interaction between slaughter age and sex had a significant effect on the carcass and physicochemical parameters, which cause different responses in males and females with increasing slaughter age. For the proximate composition and muscle fiber analysis, the interaction between the parameters studied only had a significant effect on ether extract in the breast. The increase in age resulted in chickens with higher live and carcass weight at slaughter but lower performance indices. Females had lower carcass yield and greater deposition of abdominal fat. Females had lower tenderness in the drumstick and males in the breast with increasing slaughter age, and both cuts had more intense color and redness and reduced lightness starting at the slaughter age of 90 days.

Effects of Slaughter Age of Holstein Friesian Bulls on Meat Quality: Chemical Composition, Textural Characteristics, Sensory Attributes and Fatty Acid Profile.

This study aimed to investigate the effects of slaughter age (young vs. old), muscle type (Longissimus dorsi (LD), Gluteus medius (GM)) and fat deposits (kidney knob and channel fat, subcutaneous fat, intramuscular fat) on chemical, organoleptic, textural characteristics and fatty acid composition of Holstein Friesian bull meat. For this purpose, the carcasses of 26 Holstein Friesian bulls that had been fattened on the same private farm were assigned to two experimental groups based on their age at slaughter: a young group (YG) (average age: 17.0 ± 1.0 months old) and an old group (OG) (average age: 22.0 ± 1.0 months old). The percentage of crude protein, panel tenderness score, polyunsaturated fatty acid (PUFA) and saturated fatty acid (SFA) content, the PUFA/SFA ratio and the hypocholesterolemic fatty acid (DFA)/hypercholesterolemic fatty acid (OFA) ratio of the bull carcasses decreased significantly with increasing slaughter age. By contrast, the OFA content of the carcasses significantly increased (p < 0.05) with increasing slaughter age. Advanced slaughter age resulted in lower panel tenderness scores. Additionally, the meat of the bulls in the OG was considered to be less healthy because of the less desirable fatty acid composition and nutritional indices, such as the PUFA/SFA and hypocholesterolemic/hypercholesterolemic ratios, compared to the meat from the bulls in the YG. Furthermore, the intramuscular fat and internal fat contained high percentages of PUFA and SFA and high PUFA/SFA and hypocholesterolemic/hypercholesterolemic ratios. Interestingly, the percentage of OFA content in the internal and intramuscular fat tissues decreased with increasing slaughter age. In conclusion, this study provided evidence that slaughter age and muscle and fat type are essential sources of variations in the textural characteristics, sensory panel attributes and fatty acid profile of meat from Holstein Friesian bulls.

Market weight, slaughter age, and yield grade to determine economic carcass traits and primal cuts yield of Hanwoo beef.

This study was conducted to evaluate the relationship among market weight, slaughter age, yield grade, and primal cut yield in Hanwoo. A total of 403 Hanwoo (Korean native cattle) was assessed for carcass traits such as carcass cold weight, backfat thickness, ribeye area, dressing percentage, yield index, and marbling score. The production yield of the individual major primal cuts of Hanwoo beef was also measured. Carcass cold weight, ribeye area, and backfat thickness, which affect meat quality increased with increased market weight (p < 0.05). The production yield of the ten major primal cuts also increased with increased market weight (p < 0.05). In terms of slaughter age, carcass cold weight, ribeye area, and backfat thickness all increased from 25 months to 28–29 months, and the production yield of all prime cuts also increased with increasing slaughter age. According to the meat yield grade, carcass cold weight and backfat thickness increased from grade A to grade C, although the ribeye area was not affected. The combined findings of the study suggest that slaughtering Hanwoo at the weight of 651–700 kg and 701–750 and age of 28.23 and 29.83 months could be desirable to achieve the best quality and quantity grade of Hanwoo beef. However, the positive correlation of carcass cold weight and backfat thickness, and the negative correlation of the yield index according to primal cuts yield indicated that it is necessary to couple the slaughtering management of cattle with improved genetic and breeding method of Hanwoo to increase the production yield of the major prime cuts of Hanwoo beef.

ПОКАЗАТЕЛИ КАЧЕСТВА МЯСА ЦЫПЛЯТ-БРОЙЛЕРОВ (Gallusgallus L.) ПРИ ИСПОЛЬЗОВАНИИ В РАЦИОНАХ ФЕРМЕНТАТИВНЫХ ГИДРОЛИЗАТОВ ПЕРА И КОЛЛАГЕНА

The deficit of feed-grade protein for the productive animals and poultry is presently propelling the interest toward the use of the hydrolysates of slaughter wastes as the potential protein sources. The slaughter wastes of poultry (feathers, intestines, blood, heads, shanks, meat-bone residues of the deboning) can mount up to one third of the initial bodyweight. Earlier we have developed the two-stage technology of easily digestible protein additives involving the hydrolysis and fermentation of protein from poultry slaughter wastes (primarily keratin from feathers and collagen from meat-bone residue). The study presented is a pioneer evidence that the substitution of these additives for fishmeal in diets for broilers provides more rapid growth and does not deteriorate the protein, fatty and amino acid profiles, concentrations of non-peptide, peptide and residual nitrogen, technological properties of meat. The study was performed in 2019 and aimed at the comparative evaluation of meat quality at 38 and 49 days of age in floor-housed broilers fed standard diet and three experimental diets with these hydrolysates. The broilers (cross Ross-308, 35 birds per treatment) kept in conditions of the Center for Genetics & Selection “EPH Zagorskoye” (Moscow Province) were allotted to four treatments partially slaughtered at 38 days of age and partially at 49 days. Control treatment 1 was fed a standard broiler diet with fishmeal; in experimental treatments fishmeal was substituted by enzymatic hydrolysate of feathers (treatment 2), enzymatic hydrolysate of collagen (treatment 3), mixture of these two hydrolysates with addition of probiotic Bacell M (0.2 %), and bran (0.5 %) as a source of vegetable fiber (treatment 4). It was found that supplementation of diets with the hydrolysates of keratin and collagen significantly improved live bodyweight in broilers by 8.78-10.89 % in compare to control (p £ 0.001). The content of peptide nitrogen in breast muscles in treatments 1 and 4 tended to grow with the increase in slaughter age (in treatment 1 from 0.07 at 38 days to 0.27 % at 49 days; in treatment 4 from 0.07 to 0.35 %). The number of protein fractions (with molecular weights from 100 to < 20 KDa) in meat increased with slaughter age with all studied diets. Protein of breast muscles contained more isoleucine, leucine, valine, and phenylalanine at 38 and 49 days of age in compare to thigh meat with all studied diets. The digestibility of essential amino acids in breast muscles in treatment 4 grew from 81.78 % with slaughter at 38 days to 90.29 % at 49 days. Evaluation of biological value of meat revealed better balanced ratios of the essential amino acids in breast muscles in control treatment at 38 days of age (the difference in the amino acid score 70.53 %) and in treatment 4 at 49 days of age (the difference in the amino acid score 66.48 %). In thigh meat this difference was higher in treatment 3 at 38 days of age (59.69 %) and in treatment 4 at 49 days of age (61.43 %). There were no significant differences between the treatments in concentrations of fatty acids in meat. The conclusion was made that the use of new protein additives based on the enzymatic hydrolysates of feathers and collagen in diets for broilers does not deteriorate the parameters of meat quality.

THE EFFECTS OF ENZYMATIC HYDROLYSATES OF FEATHERS AND COLLAGEN IN DIETS FOR BROILER CHICKS (Gallus gallus L.) ON MEAT QUALITY

The deficit of feed-grade protein for the productive animals and poultry is presently propelling the interest toward the use of the hydrolysates of slaughter wastes as the potential protein sources. The slaughter wastes of poultry (feathers, intestines, blood, heads, shanks, meat-bone residues of the deboning) can mount up to one third of the initial bodyweight. Earlier we have developed the two-stage technology of easily digestible protein additives involving the hydrolysis and fermentation of protein from poultry slaughter wastes (primarily keratin from feathers and collagen from meat-bone residue). The study presented is a pioneer evidence that the substitution of these additives for fishmeal in diets for broilers provides more rapid growth and does not deteriorate the protein, fatty and amino acid profiles, concentrations of non-peptide, peptide and residual nitrogen, technological properties of meat. The study was performed in 2019 and aimed at the comparative evaluation of meat quality at 38 and 49 days of age in floor-housed broilers fed standard diet and three experimental diets with these hydrolysates. The broilers (cross Ross-308, 35 birds per treatment) kept in conditions of the Center for Genetics & Selection “EPH Zagorskoye” (Moscow Province) were allotted to four treatments partially slaughtered at 38 days of age and partially at 49 days. Control treatment 1 was fed a standard broiler diet with fishmeal; in experimental treatments fishmeal was substituted by enzymatic hydrolysate of feathers (treatment 2), enzymatic hydrolysate of collagen (treatment 3), mixture of these two hydrolysates with addition of probiotic Bacell M (0.2 %), and bran (0.5 %) as a source of vegetable fiber (treatment 4). It was found that supplementation of diets with the hydrolysates of keratin and collagen significantly improved live bodyweight in broilers by 8.78-10.89 % in compare to control (p £ 0.001). The content of peptide nitrogen in breast muscles in treatments 1 and 4 tended to grow with the increase in slaughter age (in treatment 1 from 0.07 at 38 days to 0.27 % at 49 days; in treatment 4 from 0.07 to 0.35 %). The number of protein fractions (with molecular weights from 100 to < 20 KDa) in meat increased with slaughter age with all studied diets. Protein of breast muscles contained more isoleucine, leucine, valine, and phenylalanine at 38 and 49 days of age in compare to thigh meat with all studied diets. The digestibility of essential amino acids in breast muscles in treatment 4 grew from 81.78 % with slaughter at 38 days to 90.29 % at 49 days. Evaluation of biological value of meat revealed better balanced ratios of the essential amino acids in breast muscles in control treatment at 38 days of age (the difference in the amino acid score 70.53 %) and in treatment 4 at 49 days of age (the difference in the amino acid score 66.48 %). In thigh meat this difference was higher in treatment 3 at 38 days of age (59.69 %) and in treatment 4 at 49 days of age (61.43 %). There were no significant differences between the treatments in concentrations of fatty acids in meat. The conclusion was made that the use of new protein additives based on the enzymatic hydrolysates of feathers and collagen in diets for broilers does not deteriorate the parameters of meat quality.

Carcass and retail meat cuts quality properties of broiler chicken meat based on the slaughter age

This study aimed to determine the carcass and meat quality of broiler chickens based on the slaughter age (28, 30, 32, and 34 days). The carcass characteristics included live and carcass weights, carcass rate, dressing rate, and retail cut weight. The meat quality properties were determined through proximate composition, pH, color, water holding capacity (WHC), cooking yield, and shear-force. The broiler chicken live, carcass, breast, thigh, and wing weights significantly increased with the slaughter age (p < 0.05); the tenderloin weight also exhibited a similarly increasing trend. However, the carcass rate of the day 28 sample was significantly lower than the other samples (p < 0.05). The protein and ash contents of the breast exhibited an increasing trend with increasing slaughter age. The protein content of the thigh of the day 28 sample was significantly lower than that of the other samples (p < 0.05), while the ash contents of the day 28 and 30 samples were significantly lower. The redness of the breast showed an increasing trend, and the pH and lightness of the thigh exhibited a decreasing trend with slaughter age. The WHC and cooking yields of the day 30 and 32 breast and thigh samples were significantly higher than those of the day 28 and 34 samples (p < 0.05). The breast and thigh shear-force of the day 30–34 samples were significantly higher than those of the day 28 sample (p < 0.05). The present study showed that even with a two-day difference in slaughter age, the broiler chicken meat quality showed a significant difference in several characteristics.

Bioeconomic and greenhouse gas emissions modelling of the factors influencing technical efficiency of temperate grassland-based suckler calf-to-beef production systems

The objective of this study was to investigate the relative importance of key performance metrics for temperate grassland-based suckler calf-to-beef production systems on farm economics and greenhouse gas (GHG) emissions. The approach was to use data obtained from commercial farms participating in a farm improvement programme to parameterise a whole farm systems bioeconomic model. This model was then used to evaluate the biotechnical, financial and GHG emissions effects of variation in key performance metrics including calving rate, calving date, cow replacement rate, progeny live weight gain and age at slaughter. Age at slaughter and calving rate had the greatest effect on costs of production per kilogram of carcass weight. Calving rate was also the most influential parameter affecting net margin (NM) with a change of 10 percentage units (from 0.75 to 0.85 calves per cow per year) resulting in NM increasing by +€84 per hectare (ha). Age at slaughter had the greatest effect on GHG emissions; increasing slaughter age by eight months, resulted in GHG per farm increasing from 23.5 to 31.6 carbon dioxide equivalents (CO2e)/kg carcass. Although, combining high performance levels among all key performance metrics led to the greatest profitability and lowest emissions per kg carcass, the relative effects of individual parameters are not additive. This highlights interdependencies between production parameters for suckler calf-to-beef production systems.

A PBPK model to study the transfer of α-hexabromocyclododecane (α-HBCDD) to tissues of fast- and slow-growing broilers

ABSTRACTA physiologically based pharmacokinetic (PBPK) model was developed to investigate the production-specific factors involved in the transfer of α-hexabromocyclododecane (α-HBCDD) to broiler meat. The model describes growth and lipid deposition in tissues of fast- (FG) and slow- (SG) growing broilers from hatching to slaughter and simulates the exposure through the ingestion of contaminated feed or expanded polystyrene insulation material. Growth parameters were obtained from the literature while parameters relative to uptake, distribution, and elimination of α-HBCDD were adjusted using results of a previous experiment involving broilers exposed through feed throughout the rearing period or allowed to depurate before slaughter. The model was used to compare the two main edible tissues, breast and leg meat, as well as skin, and to investigate the variability within strain. Between strains and within strain, α-HBCDD assimilation efficiency (AE) is higher when the animals are slaughtered young or heavy. However, increasing slaughter age will lower α-HBCDD concentration in tissues, due to dilution. Based on fresh weight, the concentration of α-HBCDD in breast muscles and skin tends to be lower in SG than in FG broilers (−30 to +10%), while it is 10% to 80% higher in leg muscles. Compared to breast muscles, consuming leg muscles would elicit an exposure 9 and 16 times higher in FG and SG broilers, respectively. The consumption of skin together with muscles would multiply the exposure by up to 36 times compared to breast muscle alone. In case of acute exposure, the α-HBCDD concentration in tissues increased sharply, all the more since the animals are lighter in weight, and then decreased rapidly. In FG broilers, dilution through growth contributed for up to 37%, 28% and 97% to the decontamination of breast muscles, leg muscles and skin, respectively, depending on the duration of depuration before slaughter.

Volatile Profile of Grilled Lamb as Affected by Castration and Age at Slaughter in Two Breeds.

Lamb meat has a characteristic flavor which, according to the evidence to date, may be influenced by farm production factors like gender or slaughter age. Our results showed variations in the proportions of some flavor compounds in cooked lamb between rams and castrated lambs while an increase in slaughter age did not have a consistent effect on proportions of compounds.

Carcass and meat quality traits of Saanen goat kids reared under natural and artificial systems and slaughtered at different ages

Production of high-quality carcass and meat from goat kids may contribute to an increase in goat farming profitability. The aim was to compare carcass and meat quality traits of Saanen goat kids raised under natural (NR) and artificial (AR) rearing systems and slaughtered at 80 days and 120 days of age. The AR kids were separated from their dams immediately after birth and were fed with a commercial milk replacer, while the NR kids suckled their mothers. The rearing type did not affect the average daily gain, slaughter weight, hot carcass weight, empty body weight, commercial dressing percentage, subjective conformation and fatness scores. In parallel with the increase in slaughter age, the slaughter weight, hot carcass weight, empty body weight and subjective carcass conformation score increased. The rearing type had no effect on instrumental meat quality traits, except for meat Lightness (L*) and Hue values. Meat from NR kids had higher L* and Hue values 1 h and 24 h after cutting than those of AR kids. Warner-Bratzler shear force value increased with the slaughter age, but the meat lightness decreased. The ultimate pH was generally high in all groups, ranging between 5.94 and 6.10. The panellists evaluated the meat from NR kids to be more tender and juicy and also gave the highest tenderness scores to the meat obtained from the kids slaughtered at 80 days of age. As a conclusion, the slaughter age may be more determinant than the rearing type in the occurrence of carcass and meat quality characteristics.

Tsukishima Kikai Co Ltd, Japan

In practice cattle may be slaughtered at different combinations of age and weight. As each of these factors could affect meat quality traits, the present work aimed to identify which combination can be expected to increase overall meat quality of m. rectus abdominis of Charolais heifers. Totally, 40 heifers were slaughtered either at 26±1 or at 36±1 months of age. Young heifers were sampled at two different carcass weights (349±12 and 394±8 kg). Old heifers were also sampled at two different carcass weights (397±6 and 451±9 kg). The m. rectus abdominis was excised 24 h postmortem to determine metabolic enzyme activities, myosin heavy-chain isoform proportions, lipid contents, collagen content and collagen solubility. Shear force measurements were evaluated on raw and broiled meat after 14 days of ageing. Meat quality traits scored between 0 and 10 by sensory analysis. Increasing slaughter age from 26 to 36 months had no impact on either raw/broiled shear force (0.31⩽P⩽0.47) and/or meat quality traits (0.62⩽P⩽0.91) or on physicochemical properties of heifer’s meat samples. Increasing carcass weight for a similar slaughter age of 26 months had also impact neither on meat quality traits (0.52⩽P⩽0.91) nor on muscular properties. On the contrary, increasing carcass weight for a similar slaughter age of 36 months had induced a decrease of muscular shear force (raw muscle; P=0.009) and a concomitant decrease of total collagen content (P=0.03). Nevertheless, no significant impact on meat quality traits was revealed by the sensorial panel (0.13⩽P⩽0.49). Metabolic enzyme activities (0.13⩽P⩽0.86) and myosin heavy-chain proportions (0.13⩽P⩽0.96) were not significantly impacted by slaughter age and carcass weight. Thus, the impact of increasing carcass weight and/or slaughter age in young Charolais heifers has a limited impact on meat quality traits and associated muscular characteristics. Modulating heifer’s cycles (age and/or carcass weight in the studied range) appears to be a way to answer to the numerous marketing chains, without penalising meat quality traits.

Estimation of the impact of Fasciola hepatica infection on time taken for UK beef cattle to reach slaughter weight

Fasciolosis is common in UK beef cattle, but it is unclear at what levels liver fluke burdens cause production losses. This study aimed to address these uncertainties by estimating the impact of liver fluke infection on UK beef cattle productivity and investigating the use of diagnostic tests in a quantitative manner. We built three linear regression models for slaughter age by weight and different measures of liver fluke status, while accounting for sex, breed, season, year and farm of origin. Data were sourced from Scotland’s largest red meat abattoir throughout 2013 and 2014. Our Meat Hygiene Service model estimated that cattle classified as having liver fluke damage had on average 10 days greater slaughter age than animals with no evidence of fasciolosis. Our liver fibrosis model estimated that the increase in slaughter age was more severe for higher fibrosis scores. Similarly, our burden model showed an increase in slaughter age for animals with as few as 1 to 10 parasites found in their livers. Lastly, we used receiver operating characteristic curves to show that serum antibody ELISA, copro-antigen ELISA and faecal egg counting can be useful in distinguishing between animals with and without production limiting levels of fasciolosis.

Effect of age and carcass weight on quality traits of m. rectus abdominis from Charolais heifers

In practice cattle may be slaughtered at different combinations of age and weight. As each of these factors could affect meat quality traits, the present work aimed to identify which combination can be expected to increase overall meat quality of m. rectus abdominis of Charolais heifers. Totally, 40 heifers were slaughtered either at 26±1 or at 36±1 months of age. Young heifers were sampled at two different carcass weights (349±12 and 394±8 kg). Old heifers were also sampled at two different carcass weights (397±6 and 451±9 kg). The m. rectus abdominis was excised 24 h postmortem to determine metabolic enzyme activities, myosin heavy-chain isoform proportions, lipid contents, collagen content and collagen solubility. Shear force measurements were evaluated on raw and broiled meat after 14 days of ageing. Meat quality traits scored between 0 and 10 by sensory analysis. Increasing slaughter age from 26 to 36 months had no impact on either raw/broiled shear force (0.31⩽P⩽0.47) and/or meat quality traits (0.62⩽P⩽0.91) or on physicochemical properties of heifer’s meat samples. Increasing carcass weight for a similar slaughter age of 26 months had also impact neither on meat quality traits (0.52⩽P⩽0.91) nor on muscular properties. On the contrary, increasing carcass weight for a similar slaughter age of 36 months had induced a decrease of muscular shear force (raw muscle; P=0.009) and a concomitant decrease of total collagen content (P=0.03). Nevertheless, no significant impact on meat quality traits was revealed by the sensorial panel (0.13⩽P⩽0.49). Metabolic enzyme activities (0.13⩽P⩽0.86) and myosin heavy-chain proportions (0.13⩽P⩽0.96) were not significantly impacted by slaughter age and carcass weight. Thus, the impact of increasing carcass weight and/or slaughter age in young Charolais heifers has a limited impact on meat quality traits and associated muscular characteristics. Modulating heifer’s cycles (age and/or carcass weight in the studied range) appears to be a way to answer to the numerous marketing chains, without penalising meat quality traits.

Valores energéticos de rações expandidas em diferentes temperaturas para frangos de corte

RESUMO O objetivo deste estudo foi determinar os valores energéticos de rações expandidas, obtidas em diferentes temperaturas de expansão para frangos de corte em diferentes idades. As rações foram expandidas nas temperaturas: 80; 100; 120; 140ºC. Dois ensaios biológicos foram conduzidos utilizando-se o método tradicional de coleta total de excretas para determinar a energia metabolizável aparente corrigida (EMAn). Os ensaios metabólicos foram conduzidos com pintos machos Cobb, de 11 a 19 dias (fase inicial) e de 27 a 35 dias de idade (fase de crescimento), utilizando-se as mesmas aves do primeiro ensaio e, assim, preservando os tratamentos a que foram submetidas. Os valores da EMAn das rações da fase inicial foram: 2937; 2900; 2806 e 2751kcal/kg, e da fase de crescimento: 3045; 3031; 3115 e 2977kcal/kg, respectivamente. Os resultados mostraram uma redução linear dos níveis de EMn com o aumento da temperatura de expansão na idade de 11 a 19 dias. As perdas relativas entre as rações expandidas a 80 e 100ºC foram mínimas, enquanto nas temperaturas de 120 e 140ºC foram significativamente superiores. No ensaio de metabolismo para a fase de crescimento, verificou-se que as perdas relativas entre as rações expandidas a 80 e 100ºC foram pequenas (-14kcal). Para a ração expandida a 120ºC, o valor energético foi superior (84 kcal), enquanto para 140ºC foi significativamente inferior (-138kcal). Esses resultados mostram que, na fase de crescimento, os frangos de corte maximizaram o aproveitamento energético das rações na temperatura de expansão de 120ºC e que, em temperaturas acima desse nível, ocorrem altas perdas da EMAn das rações, que podem comprometer o consumo, a deposição de proteína e a conversão alimentar e, consequentemente, trazer grandes prejuízos econômicos pelo menos à idade de abate. As temperaturas de expansão de rações entre 80 e 100ºC apresentaram os melhores valores de EMAn para frangos com idade entre 15 e 10 dias, enquanto para idade de 31 a 35 dias foi de 120ºC.

Effect of slaughter age on foal carcass traits and meat quality

Meat has played a crucial role in human evolution and is an important component of a healthy and well-balanced diet due to its nutritional richness. Recent studies have shown that horsemeat may be considered as an alternative to other meat (such as beef or pork), and it may have a positive effect on human health from a nutritional point of view. This research was conducted to characterize the carcass measurement, meat quality (chemical composition, colour characteristics and textural traits) and nutritional value (fatty acid and amino acid composition) of foals slaughtered at 8 and 11 months of age (8 and 11 m groups). For this study, a total of 21 foals (10 and 11 animals from the 8 and 11-m groups, respectively) were used. The results obtained showed a positive influence on carcass characteristics with an increase in slaughter age, because 11 m animals had slightly higher values of live (275 v. 247 kg) and carcass weights (148 v. 133 kg), length of leg (72.86 v. 69.85 cm) and carcass (100.41 v. 96.30 cm) and perimeter of leg (97.68 v. 89.22 cm) compared with animals from the 8-m group. Regarding meat quality, only Fe-haeme and cholesterol content in chemical composition and luminosity (L*) in colour parameters showed significant differences. Foals from the 8-m group had the highest content of cholesterol (0.47 v. 0.28 mg/100 g of meat) and luminosity values (39.66 v. 37.88) and the lowest content of ash (1.20% v. 1.40%). In fatty acids content, only five out of 23 fatty acids showed differences between the two groups. However, an interesting change in the fatty acid profile occurred with an increase in the slaughter age. Foals from the 8-m group had the highest values of α-linolenic acid and n-3 fatty acids and the lowest values of linoleic and n-6 fatty acids, which is an interesting fact from a health point of view. Finally, slaughter age had no statistical influence on textural properties or amino acid content. As a main conclusion, animals slaughtered at 8 months of age had higher nutritional quality meat (with higher content of n-3 fatty acids) than meat from foals slaughtered at 11 months of age. The slaughter of animals at 8 months of age also reduced production costs because they ate a smaller amount of commercial fodder.

Effects of slaughter age and mass selection on slaughter and carcass characteristics in 2 lines of Japanese quail

The aim of this study was to evaluate the relationship between slaughter age and slaughter-carcass characteristics in 2 quail lines. With this aim, a Japanese quail flock subjected to mass selection to increase BW for 4 generations and a control flock that randomly mated for 4 generations were used. Birds of both lines were slaughtered at 4, 5, 6, 7, and 8 wk of age. Weights of carcass, breast, leg, wing, edible inner organs, and abdominal fat, and their percentages in BW were measured. Short-term mass selection for increased BW resulted in an increase for all slaughter and carcass traits, except edible inner organ percentage. Slaughter age had a significant effect on the studied traits, indicating that the BW and weight of carcass, carcass parts, abdominal fat, edible inner organs, and percentage of abdominal fat increased with increased slaughter age. Conversely, the carcass yield and percentages of carcass parts and edible inner organs were decreased with an increase in slaughter age. The present study showed that deterioration in carcass quality occurred with an increase in slaughter age. Furthermore, the differences between the carcass weights over the different ages ranged between 16.83 to 22.45% in favor of the selection line after a short-term mass selection.