Carcass Fat Content Research Articles

Effect of breed and sex on the body weight, slaughter traits, meat quality and meat texture parameters of rabbits

The purpose of the study was to determine the influence of breed on the growth, slaughter traits, quality traits and parameters of texture of meat obtained from Blanc de Termonde and Flemish Giant rabbits. Young animals were weaned on the 35th day of their life. The weight of animals was recorded from birth to the 84th day of life at 7-day intervals. The rabbits were slaughtered between 85th and 90th day of live. Hot carcass weight, chilled carcass weight and giblets weight (liver, lung and heart, kidneys) were recorded. The pH and the colour of the longissimus lumborum and biceps femoris muscles was measured in 45th minute and at 24 hours after slaughter. Shear force and texture parameters were measured. Flemish Giant achieve higher final body weight but lower dressing out percentage than Blanc de Termonde rabbits. Carcasses of Blanc de Termonde characterized with higher loin weight and fat content in carcass. The effect of breed fount to be significant for some components of meat colour like yellowness (b*) in 45th minute and lightness after 24 hours post mortem. The effect of sex found to be significant for acidity of meat and b* component in 45th minute after slaughter and on redness (a*) after 24 hours post mortem. Statistically significant differences between Flemish Giant and Blanc de Termonde rabbits in shear force and texture profile analysis (TPA) were stated. The sex of animals effected only on chewiness parameter for TPA of rabbit meat.

Physiological and immunological aspects of feed restriction and its beneficial impacts in fattening rabbits' productivity-an updated review.

Two feed restriction (FR) regimens are utilized with weaned rabbits including a quantitative FR (amount-limited feed or time-restricted admission to feed) and a qualitative FR (modulation of diet content especially protein and energy). The use of post-weaning FR may help in preventing post-weaning digestive disorders, stimulating compensating growth, improving feed efficiency, and decreasing carcass fat content. Interestingly, FR may contribute to changing meat's chemical composition and its physical quality attributes by regulating the morphological and biochemical characteristics of muscle fibers. Also, FR could enhance the gastrointestinal tract development, its histomorphology, and improve feed digestibility and absorption. Furthermore, FR regimens are involved in establishing gut microbial balance and enhancing the host immunological response. It might be concluded that post-weaning FR is involved in influencing the physiological and immunological aspects of growing rabbits. It might be documented that light to mild FR (i.e., 80-90% AL), early (i.e., at the first 2 weeks post-weaning), and relatively short in duration (i.e., for 2-3 weeks) had no negative effects on live body weight, while severing FR reduced live body weight in comparison with ad libitum rabbits.

The Effect of Replacing Whole-Plant Corn Silage with Daylily on the Growth Performance, Slaughtering Performance, Muscle Amino Acid Composition, and Blood Composition of Tan Sheep.

The shortage of high-quality coarse feed resources is the main factor that restricts the development of animal husbandry in many developing countries. The present study aimed to investigate the effects of replacing corn silage with daylily silage on the growth performance, slaughter performance, blood biochemical indicators, meat quality, and muscle amino acid composition of Tan sheep. A total of 72 healthy Tan sheep were randomly assigned to four groups. In each group, 0%, 20%, 40%, and 60% of corn silage were replaced with daylily silage (denoted as CON, HC20, HC40, and HC60, respectively). Tan sheep fed with daylily silage showed no significant adverse effects on their growth performance, meat quality, and muscle amino acid composition (p > 0.05). Some increase was observed in the carcass fat content value (GR-value, p < 0.05), thickness of backfat (p < 0.05), and the blood urea level (p < 0.05). These findings indicate that the utilization of daylily silage instead of whole-plant corn silage has no adverse effects on the growth performance and meat quality of Tan sheep, thus indicating that it can partially replace whole-plant corn feed as a feed resource for Tan sheep.

The effect of age and sex on carcass traits and body composition of Hungarian yearling farmed red deer (Cervus elaphus hippelaphus)

Carcass characteristics were studied in 80 young Hungarian red deer in different ages (12, 15, 18 and 20 months of age). In all age group 10 male and 10 female were slaughtered. The dressed carcass weight in skin varied between 53.72 and 65.66% of live weight. The first class lean meat varied between 14.3 and 16.6% of live weight.The live weight, carcass weight increased with the age and differed also between sexes. The highest dressing percentages were found at 20 months of age in both sexes (♂: 65.7%, ♀: 62.5%). Mainly the hinds had higher loin, leg and shoulder proportions of carcass at 20 months of age than the stags.The carcass muscle, bone and fat content were measured by computer tomography. These traits were grown and their proportion changed with the age. The bone to muscle ratio gradually decreased with the age while the fat to muscle ratio increased after 15 months of age (♂: from 0.13 to 0.17, ♀: from 0.15 to 0.18). At 18 month of age the hinds had higher bone to muscle and fat to muscle ratio than the stags'.The fat percentage of carcasses increased with the age in both sexes (♂: from 8.01% to 11.04%, ♀: from 8.40% to 11.28%). The hinds had higher values than the stags but it was significant just at 20 months of age.From the meat quality attributes there were found differences between ages in the case of pH, lightness, drip loss, cooking loss and shear force. The highest pH was found at 12 months of age in both sexes. There were found 5% intermediate pH (6.2 < pH < 5.8) at 12 and 15 months of age, all of them were male. The highest lightness values were observed at 18 months of age in both sexes (♂: 13.47, ♀: 14.90). There were differences between sexes in pH at all ages, except 15 months of age, and at 18 months of age in redness and lightness.Based on our results, the optimal slaughtering time for Hungarian red deer is 20 months of age, because this is when the dressing percentage is the best for both sexes. Meat quality traits changed with age, and gender differences sexes were the most pronounced for these traits at 18 months of age.

Transcriptomics and metabolomics reveal improved performance of Hu sheep on hybridization with Southdown sheep

Consumers are increasingly demanding high-quality mutton. Cross breeding can improve meat quality and is widely used in sheep breeding. However, little is known about the molecular mechanism of cross breeding sheep meat quality. In this study, male Southdown and female Hu sheep were hybridized. The slaughter performance and longissimus dorsi quality of the 6-month-old hybrid offspring were measured, and the longissimus dorsi of the hybrid offspring was analyzed by transcriptomics and metabolomics to explore the effect of cross breeding on meat quality. The results showed that the production performance of Southdown × Hu F1 sheep was significantly improved, the carcass fat content was significantly decreased, and the eating quality of Southdown × Hu F1 sheep were better. Compared with the HS group (Hu × Hu), the NH group (Southdown × Hu) had 538 differentially expressed genes and 166 differentially expressed metabolites (P < 0.05), which were significantly enriched in amino acid metabolism and other related pathways. Up-regulated genes METTL21C, PPARGC1A and down-regulated gene WFIKKN2 are related to muscle growth and development. Among them, the METTL21C gene, which is related to muscle development, was highly correlated with carnosine, a metabolite related to meat quality (correlation > 0.6 and P < 0.05). Our results provide further understanding of the molecular mechanism of cross breeding for sheep muscle growth and meat quality optimization.

Diet-Induced Thermogenesis Is Lower in Rats Fed a Lard Diet Than in Those Fed a High Oleic Acid Safflower Oil Diet, a Safflower Oil Diet or a Linseed Oil Diet

The objectives of the present study were to examine the effects of dietary fats differing in fatty acid composition on diet-induced thermogenesis, sympathetic activity in brown adipose tissue and body fat accumulation in rats. Rats were meal-fed for 12 wk an isoenergetic diet based on lard, high oleic acid safflower oil, safflower oil or linseed oil, and norepinephrine turnover rates in brown adipose tissue were then estimated. Whole-body oxygen consumption after the meal indicated that diet-induced thermogenesis was significantly lower in rats fed the lard diet than in those fed the other diets. The norepinephrine turnover rate in the interscapular brown adipose tissue was also significantly lower in the lard diet group than in the other diet groups. The carcass fat content was significantly higher in the lard diet group than in the other diet groups, whereas the abdominal adipose tissue weights were the same in all diet groups. These results suggest that the intake of animal fats rich in saturated fatty acids, compared with the intake of vegetable oils rich in monounsaturated or polyunsaturated fatty acids, decreases diet-induced thermogenesis by a decline of sympathetic activity in brown adipose tissue, resulting in the promotion of body fat accumulation.

Does the epigenetic expression of obesity, insulin resistance and their metabolic sequelae contribute to brain senescence?

Cognitive senescence and brain shrinkage have been reported in Alzheimer’s disease and is often associated with obesity but the pathophysiologic factors which bring about the neural declines remain unclear. A retrospective examination of factors of Insulin resistance and obesity in lean and obese rats indicated that final body weights of obese phenotype were more than double those of their lean littermates throughout adulthood, and carcass fat content at 10.5 months of age 15-fold greater than similarly fed lean littermates. In addition, the life span of the obese phenotype was decreased by approximately 30% in both male and female rats compared to their lean littermates. In addition, glycemic parameters indicated that the obese rats developed significant insulin resistance, while brain lipid, protein and DNA content were significantly reduced by one third or more in the obese phenotype by ~10 months of age, when they had approached their peak body weights. These observations suggest that the onset and progression obesity and its metabolic sequelae contributes to brain shrinkage, decreased DNA and protein content, key factors in the development of cognitive senescence in aging in this strain of rat.

The Epigenetic Expression of Obesity and Its Metabolic Sequelae Contribute to Brain Senescence and Decreased Longevity in Aging Obese LA/Ntul//-cp Rats

Cognitive senescence and brain shrinkage have been reported in Alzheimer’s disease and is often associated with obesity but the pathophysiologic factors which bring about the neural declines remain unclear. A retrospective examination of factors of Insulin resistance and obesity in lean and obese rats indicated that final body weights of obese phenotype were more than double those of their lean littermates throughout adulthood, and carcass fat content at 10.5 months of age 15-fold greater than similarly fed lean littermates. In addition, the life span of the obese phenotype was decreased by approximately 30% in both male and female rats compared to their lean littermates. In addition, glycemic parameters indicated that the obese rats developed significant insulin resistance, while brain lipid, protein and DNA content were significantly reduced by one third or more in the obese phenotype by ~10 months of age, when they had approached their peak body weights. These observations suggest that the onset and progression obesity and its metabolic sequelae contributes to brain shrinkage, decreased DNA and protein content, key factors in the development of cognitive senescence in aging in this strain of rat.

A matter of body weight and sex type: Pig carcass chemical composition and pork quality

This study compares minced carcass chemical composition and meat quality of castrated (CM), immunocastrated (IM) and entire male (EM), and female (FE) pigs at 70, 100 and 120 kg target body weights (TBW) (n = 80; 20 per sex). Sex affected fat, protein, and moisture content of the minced carcasses. Carcass fatty acid (FA) composition was affected by sex, with higher saturated and monounsaturated FA content in CM than in FE, IM and EM, and higher polyunsaturated FA in CM than in EM, with FE and IM in between. Except for intramuscular fat, which was higher in CM than in FE and EM, no significant differences between sexes were found in meat quality. TBW affected carcass chemical composition and some meat quality traits. An interaction between sex and TBW was found with IM approaching EM or CM depending on TBW.

The effect of various doses of vitomolt as a feed additive on meat quality and feed nutrient retention in mud crab fattening

Vitomolt is a feed additive in fattening mud crabs (Scylla olivaceae). The study aimed to determine the best dose of vitomolt for meat quality and nutrient retention for fattening Scylla olivaceae. It was conducted at the Educational Farm of Universitas Hasanuddin, Barru Regency, Indonesia. The treatments were various doses of vitomolt in the feed, which 0, 200, 400, 600 mg kg−1 of feed. Rearing was held for 60 days and fed 5% body weight daily. The analysis showed that the dose of vitomolt in the feed affected the percentage of meat carcass weight, fat content, fat retention, and crab energy retention. However, it did not affect protein content, crude fiber, Nitrogen-Free Extract (NFE), ash content, and crab protein retention. The best percentage of meat carcass weight at a dose of vitomolt 400 mg kg−1 and same from a dose of 200 mg kg−1, while the best fat content, fat retention, and energy at a vitomolt dose of 600 mg kg−1 and different from a dose of 400 and 200 mg kg−1, but different from the control. Vitomolt with a 200 mg kg−1 of feed is the best dose to produce the highest meat quality and nutrient retention in fattening crabs.

Evaluation of Different Protein Blends on Growth Performance, Nutrient Utilization and Carcass Composition of Nile Tilapia (Oreochromis niloticus) Fingerlings

The effects of different protein blends (gliricidia/moringa leaf meals, soybean meal and defatted palm weevil larvae) on Nile tilapia (Oreochromis niloticus) fingerlings were studied for a 10-week feeding period. Six diets with 30 percent crude protein content were formulated, the protein sources were included in equal ratios. Diets were designated as fishmeal/soybean (FMS), palm weevil/soybean (PWS), palm weevil/ moringa (PWM), palm weevil/ gliricidia (PWG), palm weevil/soybean/moringa (PSM) and palm weevil/soybean/gliricidia (PSG). Trials were carried out in triplicates with each having ten (10) fish in a total of 18 tanks. Fish fed diet PSG had the highest mean weight gain of 4.35±0.08 and protein efficiency ratio (PER) of 1.14±0.02. These values were significantly different (P&lt;0.05) from those recorded for fish on other diets. Fish fed diet PSG gave the lowest food conversion ratio (FCR) of 1.10±0.02, with those on diet PWG recording the least. Fish fed diets containing soybean meal (PSM and PSG) gave better performances than those without it. The carcass protein, ash and fat contents differed significantly (P&lt;0.05). This results showed that Oreochromis niloticus fingerlings fed a mix of protein blends could give good performance in terms of growth, nutrient utilization and carcass constituents.

Effect of leptin C528T and leptin C73T polymorphisms and pregnancy on adipose tissue formation and carcass grade in Aberdeen Angus heifers and first-calf cows.

Background and Aim:The leptin (LEP) gene plays a role in the regulation of the activity required to obtain food, energy metabolism, and fat deposition and affects the body composition of animals. Lipogenesis is an ineffective process. A lot of energy from feed is expended on the synthesis of adipose tissue. This study aimed to determine the effect of LEP C528T and LEP C73T polymorphisms and pregnancy on adipose tissue formation and carcass grade in Aberdeen Angus heifers and first-calf cows.Materials and Methods:Heifers (n = 49) and first-calf cows (n = 30) were grouped according to their genotype for LEP C528T and LEP C73T polymorphisms at the age of 24 months. DNA samples were isolated from whole blood. Experimental animals were slaughtered at the age of 24 months, and a chemical analysis of samples of longissimus dorsi muscle and ground beef was performed.Results:The maximum internal fat weight, back-fat thickness, and fat content of the longissimus dorsi muscle and ground beef were determined in heifers heterozygous for both LEP C528T and LEP C73T polymorphisms. The ranking of genotypes in terms of adipose tissue formation did not change in first-calf cows compared to heifers carrying the same LEP gene variants. Pregnancy had a more significant (p < 0.05–0.001) effect on slaughter parameters and lipogenesis in animals of different genotypes than studied polymorphisms. Heterozygosity of the LEP gene was much more strongly expressed in the carcass grade of heifers. ”Prime” grades were assigned to 66.7% of carcasses heterozygous for LEP C528T and “Top Choice” to 58.8% of carcasses with LEP C73T nucleotide substitutions.Conclusion:LEP C528T and LEP C73T polymorphisms were shown to affect the extent of fat formation in Aberdeen Angus heifers and first-calf cows. Animals with heterozygous genotypes exhibited the maximum development of internal fat, back-fat, and intramuscular fat. Pregnancy had a more significant effect on slaughter parameters and adipose tissue formation than studied polymorphisms. First-calf cows had a significantly lower fat content in carcasses than heifers. These results can aid in the production of efficient mature herds of Aberdeen Angus cattle.

INTERNAL FATS OF ROSS 308 BROILER CHICKENS AFTER APPLICATION OF GRAPE, FLAX AND PUMPKIN POMACE INTO THEIR DIET

Poultry fat is interesting in terms of fatty acid composition, especially due to the higher content of unsaturated fatty acids compared to mammals. However, internal fats are considered as one of the wastes from poultry processing. In previous experiments, we observed the effect of grape, flax and pumpkin pomace on the meat performance and chemical composition of broiler chicken muscle. Therefore, the aim of this work was to examine the effect of these pomaces on the formation of internal fats in Ross 308 broiler chickens. The control group (C) was fed with a feed mixture (FM) without antibiotics and growth stimulators. In the experimental diets, wheat in FM was replaced by 1, 2 and 3% red grape pomace, variety Alibernet (groups E1, E2 and E3), 2 and 4% flax pomace (groups E4 and E5) and 2 and 4% pumpkin pomace (groups E6 and E7). The chickens were fed and watered ad libitum for 42 days. Amounts of internal fats are presented as % from carcass weight (CW). Of the internal fats in females, only heart fat was significantly affected (P≤0.05) (least in E5 and E7 – 0.20%). In males, on the other hand, we found significant differences (P≤0.001) in other fats: abdominal fat was highest in E2 and E3 (0.94 and 0.91%, respectively), gizzard fat was highest in E2 (0.59%) and internal fats together in E2 and E3 (1.67 and 1.48%, respectively). The results show that negatively higher internal fat content of the chicken carcass was caused mainly by the addition of 2 and 3% RGP in the diet of Ross 308 chickens.

Energy and nutrient intake on white striping, wooden breast and carcass composition in broilers from three genetic lineages at different ages

Increased incidence of myopathies and/or changes in broiler carcass composition leads to poor visual appearance and carcass condemnation on the slaughter line, or even subsequent consumer product rejection, consequently, economic losses. This study,was set to assess the incidence of white striping (WS), wooden breast (WB) and the carcass composition of three different genetic lineages of broilers fed with three different dietary nutrient densities. The experiment was conducted with a 4320 broilers, in a completely randomized, 3 × 3 factorial design, assessing three genetic lineages (Embrapa 021 – moderate growth, Cobb 500 and Ross 308 – rapid growth) and three dietary nutrient densities (ND): low, medium and high. Pelleted feed and water were consumed ad libitum. Daily digestible lysine intake (DdLysI – g/d), daily apparent metabolizable energy (DAMEI – kcal/d) and average daily weight gain (ADWG - g/d) were recorded for each evaluation period. At the ages of 28, 35, 42 and 49 days, 16 animals per treatment were slaughtered and submitted to WS, WB and carcass composition analysis. Ordinal logistic regression was used to analyse the WS and WB data. DdLysI, DAMEI, ADWG and carcass composition data were subjected to analysis of variance and the means compared by Tukey’s test at a 5% significance level. An interaction effect (P < 0.05) showed that broilers from Embrapa 021 presented lower DdLysI and DAMEI from 1 to 35, 42 and 49 days, as well as lower ADWG for every period, regardless of the dietary ND. The lowest incidences of WS and WB were found for Embrapa 021 lineage, regardless of diet, compared to the other lineages (P < 0.05). There was an interaction effect for the carcass composition at 49 days for moisture, protein, fat and collagen (P < 0.05). At 28, 35 and 42 days the animals on the High ND diet had a higher moisture and protein content, and lower fat content. In relation to the genetics, the Embrapa 021 lineage displayed lower moisture and protein content and higher carcass fat content. The rapid growth broilers are more susceptible to developing breast muscle myopathies and present higher moisture and protein content and lower fat content in the carcass. High dietary nutrient density results in a higher moisture and protein content in the carcass.

Effect of Long-Acting Selenium Preparation on Health and Productivity of Sheep.

Simple SummarySelenium (Se) plays an important role in many biological functions, especially in the immune system. We studied the effects of injectable Se supplementation on the immune status, blood parameters, body weights and average daily gain of lambs. The results of the study indicate that the Se preparation induced an increase in the values of the parameters of both non-specific and specific immunity. Lambs from the experimental group achieved higher body weights and daily gains. The present findings can contribute to a better understanding of the biological functions of Se and improve the efficacy of this mineral in livestock production.The aim of this study was to determine the effects of long-acting selenium (Se) preparation in sheep. The experimental material comprised Skudda ewes and their lambs. The animals were divided into two equal groups: C-control, and E-experimental. Between days 70 and 80 of pregnancy, group E ewes were injected with Se preparation (Barium Selenate Injection, BVP Animal Care, Ireland) at f 1 mL/50 kg body weight. Hematological, biochemical and immunological blood parameters as well as Se levels were analyzed in ewes. The growth rate of lambs, the dimensions of the musculus longissimus dorsi (MLD) cross-section, and fat thickness over the loin-eye area were also determined. It was found that barium selenate stimulated the mechanisms of humoral and cellular immunity. The injection was an effective form of Se supply, which was confirmed by its increased concentration in the blood serum of lactating ewes. The offspring of the experimental ewes were characterized by a faster growth rate, and they achieved significantly higher body weight (p ≤ 0.05) at 100 days of age. The lambs also had significantly higher parameters of MLD (p ≤ 0.05) at similar carcass fat content.

Carcass characteristics and selected meat quality traits from commercial broiler chickens of different origin.

The aim of the study was to compare carcass and meat quality traits in 42-day-old Ross 308 and Cobb 500 broiler chickens. Forty carcasses were studied. Acidity (pH24 ) and electrical conductivity (EC24 ) of pectoralis major muscle and drumstick were determined 24 h postmortem. After carcass cutting, samples of breast and leg meat were collected for determination of quality traits. Broiler genotype had a significant effect on abdominal fat content in carcass and on water, protein, fat, sodium, and magnesium content in breast meat. Bird origin had an effect on the lightness, yellowness, horizontal diameter of muscle fiber, horizontal:vertical (H:V) diameter ratio, and most textural characteristics of pectoralis major muscle, as well as on the pH (pH24 ), electrical conductivity (EC24 ), and yellowness (b*) of leg muscles. Sex of birds had a significant effect on carcass weight, water, fat and collagen content, L*, a*, b* color attributes, and chewiness and gumminess of breast meat and on water and protein content in leg muscles. The present study provided information on the differences in carcass and meat quality between Ross 308 and Cobb 500 broiler chickens.

Relationship between energy intake and growth performance and body composition in pigs selected for low backfat thickness.

Genetic selection of pigs over recent decades has sought to reduce carcass fat content to meet consumer demands for lean meat in many countries (e.g., Australia). Due to the impacts of genetic changes, it is unknown whether the carcass fat measures are still responsive to energy intake. Thus, the present experiment aimed to quantify the relationship between tissue composition and dietary energy intake in finisher pigs selected for low carcass backfat. Intact male and female pigs (n = 56 for each sex; Primegro Genetics, Corowa, NSW, Australia) were fed seven different amounts of an amino acid adequate wheat-based diet containing 14.3 MJ digestible energy (DE)/kg to provide the following daily DE intakes- 25.8, 29.0, 32.6, 35.3, 38.5, 41.5, and 44.2 (ad libitum) MJ DE/d for males, and 25.8, 28.9, 32.0, 35.6, 38.3, 40.9, and 44.5 (ad libitum) MJ DE/d for females between 60 and 108 kg live weight. Body composition of anesthetized pigs was measured using the dual energy X-ray absorptiometry (DXA) method when individual pigs reached 108 kg, and protein, fat, and ash deposition rates were calculated. Pigs were slaughtered on the second day post-DXA scan for carcass backfat measurement. The results showed that the carcass backfat thickness (standardized at 83.7 kg carcass) increased by 0.125 mm for every MJ increase in daily DE intake in male pigs (P = 0.004; R2 = 0.130), but carcass backfat of female pigs (standardized at 85.1 kg carcass) was not responsive to daily DE intake. Whole-body fat composition and fat deposition rate increased linearly (both P < 0.01) in male pigs but quadratically (both P < 0.01) in female pigs in response to DE intake. Every MJ increase of daily DE intake increased the rate of daily protein deposition by 3.8 g in intact male pigs (P < 0.001; R2 = 0.781) and by 2.5 g in female pigs (P < 0.001; R2 = 0.643). In conclusion, the selection for low backfat thickness over the last two decades has altered the response of fat deposition and backfat thickness to energy intake, particularly in female pigs. Despite this change, the linear relationship between DE intake and protein deposition rate was maintained in these modern genetics.

Restrictive nutrition and compensatory growth of broilers: Impact on growth production results and carcass characteristics

Increase in growth rate through genetic selection and improved nutrition in broiler chickens has been associated with high body fat deposition. This is particularly evident under ad libitum feeding that is normally practiced. Excessive fat deposition in the body of broilers is a common problem for poultry producers and consumers. Studies have shown that feed restriction could decrease fat content and increase protein deposition in carcasses, thus resulting in their improved composition. In addition to determining the optimal time to start and the duration of the restrictive nutrition, the success of the given programs largely depends on the intensity of the restriction, as well as the type of applied technique. Considering that in a large number of studies, the application of restrictive programs resulted in a reduction of body fat in broilers, but at the same time the desired body weight was not achieved at the slaughter (market) age, these programs should not be a priori rejected as ineffective. It is necessary to determine whether the market price of the obtained product (poultry meat) with its reduced fat content justifies the lower body weight of broilers achieved at the end of the fattening period.

Comparison of Genetic Merit for Weight and Meat Traits between the Polled and Horned Cattle in Multiple Beef Breeds.

Simple SummaryBeef production has expanded worldwide through cattle adaptation to diverse environmental and husbandry conditions. The beef industry faces societal challenges from animal welfare perspectives, including dehorning and disbudding, which are common farm practices to limit animal and handler injuries by the horned cattle. Most cattle breeds were originally horned, and reluctance to poll breeding existed because of perceived negative correlations between polledness and production. In Australia, population trends indicate a recent rise to above 50% of poll types in six breeds (Charolais, Hereford, Limousin, Simmental, Shorthorn, and Droughtmaster), and two breeds with lower but increasing rates of polledness (Brahman and Santa Gertrudis). Overall, recently estimated breeding values of 12 investigated production traits have not shown consistently negative trends within and across breeds. Thus, polledness should not be considered as detrimental. Cautious breeding plans are warranted to avoid inbreeding depression in breeds with lower poll frequency. These findings should support the augmented poll breeding across the beef industry.Breeding for polled animals is deemed the most practical solution to eradicate horns naturally and circumvent management costs and risks on health and welfare. However, there has been a historical reluctance by some farmers to select polled animals due to perceived lower productivity of their calves. This study has compared estimated breeding values (EBVs) between horned and polled animals (N = 2,466,785) for 12 production and carcass traits to assess historical (before 2000) and recent (2000–2018) genetic implications of poll breeding. Older generations of the polled animals in most breeds had significantly lower (Bonferroni-corrected p = 0.05) genetic merits for live (birth to maturity) and carcass weights, milk, meat quality, and fat content traits. Substantial gains of genetic potential were achieved during 2000 to 2018 in each breed, such that polled animals have significantly improved for the majority of traits studied. Generally, polled cohorts showed advantageous EBVs for live and carcass weights irrespective of the lower birth weights in some breeds. While Polled Brahman showed inferior production parameters, the poll genetics’ effect size (d) and correlation (r) were very small on recent birth weight (d = −0.30, r = −0.08), 200 days (−0.19, −0.05), 400 days (−0.06, −0.02), 600 days (−0.05, −0.01), mature cow live weight (−0.08, −0.02), and carcass weight (−0.19, −0.05). In conclusion, although there is some evidence that historical selection for polled breeding animals may have reduced productivity, there is strong evidence that more recent selection for polled genotypes in the breeds studied has not resulted in any adverse effects on genetic merit.

Dietary inclusion of nonconventional roughages for lowering enteric methane production and augmenting nutraceutical value of meat in cull sheep

A study was undertaken to determine the effect of nonconventional roughages on nutrient utilization, enteric methane production and meat quality in cull ewes. Thirty six adult ewes (>5 yrs, BW = 30.3 ± 0.92 kg) were divided into four groups and fed for 90 days (d) on four complete feed blocks containing 400 g/kg different roughages and 600 g/kg concentrate mixture. Roughages were Cenchurus ciliaris hay (T-Cc), Crotalaria medicaginea hay (T-Cm), Blepharis scindica (T-Bs) and Trigonella foenum-graecum straw (T-Tf). Apparent digestibility of the all nutrients were higher (P < 0.05) in T-Bs treatment except crude protein. Enteric methane emission (g/kg DMI) was lower in T-Bs with an average reduction of 5.5 % digestible energy loss as compared to other treatments. Feeding of complete feed blocks containing B. scindica herbage (T-Bs) reduced enteric methane emission by 49.3 %, T. foenum-graecum straw (T-Tf) by 35.5 % and C. medicaginea (T-Cm) by 22.3 % per kg DOMI as compared to C. ciliaris hay (T-Cc). Likewise, there was a shift in rumen fermentation towards propionigenesis and higher (P < 0.05) concentration was recorded in T-Bs and T-Cm treatments. Body weight gain of cull ewes and total fat content (%) of carcass was higher (P < 0.05) in T-Cm and T-Bs treatment while, it was lower in T-Tf. However, fatty acid profile of Longissimus thoracis muscle showed higher (P < 0.05) proportion of C18:3n3, C18:2c9t11 and total PUFA in ewes fed blocks containing T. foenum-graecum straw (T-Tf). From the present findings it can be concluded that feeding of complete feed blocks consisting B. scindica and T. foenum-graecum straw to ewes reduced enteric methane emission by 49.3 and 26.8 percent respectively. Additionally, dietary inclusion of feed blocks with T. foenum-graecum straw improved desirable fatty acid contents in the muscles of ewes. Hence, including these alternative roughages in the diet of cull ewes could be a promising approach to reduce enteric methane emission and augment nutraceutical value of meat with desirable fatty acid contents.