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The purpose of this study was to evaluate productive, reproductive performance, carcass characteristics, chemical composition and meat quality of four varieties of guinea fowl. A total of 200 guinea fowls from White, Pearl, Lavender and Mixed varieties were reared in an intensive production system from 0 to 20 wk of age. Guinea fowl keets were reared provided with balanced recommended ration (Starter diet: ME 2,950 kcal/kg, CP 23% for initial 8 wk; Grower diet: ME 2,950 kcal/kg, CP 16% for 9 to 16 wk and Layer diet: ME 2,900 kcal/kg, CP 17% from 17 wk till the end of the laying period). There was no significant (P < 0.05) difference found in body weight (BW) from 0 to 20 wk old guinea fowl. However, BW of Pearl variety was greater than other varieties numerically (Table 1). At adult age, a total of 40 birds (10 from each variety) were slaughtered according to standard method and carcasses were cut into parts. Weights were taken for all carcass parts. Proximate analysis and meat quality were performed on breast and thigh meat, as well as on abdominal fat of the studied guinea fowls. Carcass weight (930.33 ± 27.37 g), dressing percentage (67.6 ± 0.013%), breast weight (228.33 ± 13.68 g) and thigh weight (166.33 ± 6.69 g) of Pearl variety was significantly (P < 0.001) greatest (Table 2). Measured abdominal fat (23 ± 0.13) was found to be significantly (P < 0.001) greatest in Pearl variety. Furthermore, there was no significant difference found in crude protein among breast and thigh meat of different varieties. The ether extract (EE) and crude fiber (CF) of breast (EE: 0.27, CF:0.33) and thigh meat (EE: 0.20, CF:0.33) of Lavender variety was significantly (P < 0.05) less than other varieties (Table 3). In case of reproductive parameters, Pearl variety exhibited better egg fertility (65.72 ± 6.10) numerically and significantly greater (P < 0.001) hatchability percentage (76.75 ± 3.88) than other varieties. Meat color values of all the varieties of guinea fowl found in this study are in line with the demands of poultry consumers (Table 4). Regarding water holding capacity (WHC) and drip loss (DL), there was no discernible difference (P > 0.05). Considering all the parameters especially cooking loss (CL) and pH, there was a noticeable difference (P < 0.05) in which the Lavender (CL: 24.81 ± 0.69, pH:6.12 ± 0.05) and White variety (CL: 25.35 ± 0.69, pH: 6.11 ± 0.05) performed better than the other varieties. [ABSTRACT FROM AUTHOR]

A fully functional myostatin gene inhibits muscle fiber growth. The objective of the present study was to quantify the association between 21 known myostatin mutations with both calving and carcass traits in 12 cattle breeds. The myostatin genotypes of 32,770 dam-progeny combinations were used in the association analysis of calving dystocia, with the genotypes of 129,803 animals used in the mixed model association analyses of carcass weight, conformation, and fat score. The mixed model included additive genetic, maternal, and permanent environmental effects where appropriate. The mutant genotypes of nt821, Q204X, and F94L were all associated (P < 0.01) with more calving difficulty when present in either the dam or the progeny. The nt821 deletion had the greatest association with calving difficulty when the homozygous deletion was present in either the calf (0.37 points greater calving difficulty score relative to calves carrying no copies of the deletion based on a one to four scale) or the dam (1.30 points greater calving difficulty score relative to dams carrying no copies of the deletion), although the association between the calf’s nt821 genotype and calving difficulty differed depending on the nt821 genotype of the dam. With the exception of nt748_78, nt414, and nt374_51, all other seven segregating myostatin variants were associated (range of allele substitution effect size relative to animals with no copies of the mutant allele) with carcass weight (2.36 kg lighter to 15.56 kg heavier), all 10 segregating variants with conformation (0.15 units less conformed to 2.24 units more conformed assessed on a scale of 1 to 15), and all segregating variants other than E226X with carcass fat (0.23 units less carcass fat cover to 3.85 units more carcass fat cover assessed on a scale of 1 to 15). Of these, the F94L, Q204X, and nt821 mutations generally had the greatest association with all three carcass traits, giving rise to heavier and more conformed carcasses. Despite the antagonistic genetic relationship between calving difficulty and carcass traits, the nt374_51, F94L, and E226X mutations were all associated with improved carcass merit while having minimal expected consequences on calving difficulty. Thus, animals carrying these mutation(s) may have favorable genetic merit for calving difficulty and carcass merit. Furthermore, depending on the dam genotype, a bull with two copies of the nt821 mutation can produce progeny with improved carcass merit while minimizing calving problems. [ABSTRACT FROM AUTHOR]

Hanwoo beef cattle are well known for the flavor and tenderness of their meat. Genetic improvement programs have been extremely successful over the last 40 yr. Recently, genomic selection was initiated in Hanwoo to enhance genetic progress. Routine genomic evaluation based on the single-step breeding value model was implemented in 2020 for all economically important traits. In this study, we tested a single-step marker effect model for the genomic evaluation of four carcass traits, namely, carcass weight (CW), eye muscle area, backfat thickness, and marbling score. In total, 8,023,666 animals with carcass records were jointly evaluated, including 29,965 genotyped animals. To assess the prediction stability of the single-step model, carcass data from the last 4 yr were removed in a forward validation study. The estimated genomic breeding values (GEBV) of the validation animals and other animals were compared between the truncated and full evaluations. A parallel conventional best linear unbiased prediction (BLUP) evaluation with either the full or the truncated dataset was also conducted for comparison with the single-step model. The estimates of the marker effect from the truncated evaluation were highly correlated with those from the full evaluation, ranging from 0.88 to 0.92. The regression coefficients of the estimates of the marker effect for the full and truncated evaluations were close to their expected value of 1, indicating unbiased estimates for all carcass traits. Estimates of the marker effect revealed three chromosomal regions (chromosomes 4, 6, and 14) harboring the major genes for CW in Hanwoo. For validation of cows or steers, the single-step model had a much higher R2 value for the linear regression model than the conventional BLUP model. Based on the regression intercept and slope of the validation, the single-step evaluation was neither inflated nor deflated. For genotyped animals, the estimated GEBV from the full and truncated evaluations were more correlated than the estimated breeding values from the two conventional BLUP evaluations. The single-step model provided a more accurate and stable evaluation over time. [ABSTRACT FROM AUTHOR]

Nutrition represents 70% of pig production costs, particularly protein; therefore, decreasing protein costs is of capital importance. Reducing crude protein (CP) contents to levels below recommended whilst supplementing with amino acids (AAs) is an interesting strategy to reduce costs without decreasing production performances. It has been conducted essentially in lean genotypes during the growth stage. Few studies address heavy genotypes or sex differences during the finishing period. Our objective is to study carcass and meat (loin) traits of heavy [Duroc X (Landrace X Large- White)] male and female pigs during the finishing stage under a 2% CP reduction with crystalline AA supplementation, hypothesizing that both sexes will be affected equally. In total, 60 males and 60 females, 9 wk old animals were used and allotted in split-sex pens (6 pigs/pen) with water and dry feed ad libitum. At 15 wk of age, when pigs weighed an average of 68 kg, two isoenergetic diets with different CP levels were provided (145 and 125 g CP/kg, control and low-CP) during the last 42 d of fattening. In the low-CP diet, crystalline AAs were added. On last day of the trial, animals weighed 116.5 kg on average and were slaughtered. Hot carcass weights and yields, ham fat thickness, lean meat percentage and boar taint by human nose scoring were determined. Loin samples (one per pen) were used to determine thawing losses, pH, color, Texture Profile Analysis (TPA: hardness, cohesiveness, springiness) and chemical composition (moisture, ash, protein, collagen, fat, and saturated fat). Data were analyzed using the simple least squares models that included dietary treatment and sex and their interaction as fixed effects with the pen as the experimental unit. Carcass weights were greater in control males than in females (91.2 vs 85.7 kg; P < 0.05). No effect of sex or diet was detected on carcass yields, lean contents or ham subcutaneous fat thickness. There was a great impact of sex for loin subcutaneous fat thickness, with males having 7 to 8% greater values in both dietary treatments (P = 0.011). Low-CP females had a greater percentage of carcasses of greater lean content compared with the three other groups (P < 0.05). Boar taint, carcass pH, color traits, chemical analysis and TPA did not differ across diets. A strong dietary influence was noticeable with animals of both sexes in the Low-CP diets having greater fat and saturated fat contents than animals in the control groups (P = 0.02). In conclusion, the 20g/kg CP reduction supplemented with AAs can efficiently be used in heavy Duroc sire line genotype during the finishing phase without leading to major impairments in carcass or meat traits, regardless of sex. [ABSTRACT FROM AUTHOR]

Objectives were to evaluate the effects of temperament at feedlot arrival and breed type on productivity, feed efficiency, feeding behavior, and carcass quality traits in finishing beef heifers, and to examine interactions between temperament and breed type. Heifers (Angus, Braford, Brangus, and Simbrah, N = 411, BW = 280 kg) were fed a high-grain diet (ME = 3.0 Mcal/kg DM) in pens equipped with electronic feed bunks. Quality grade (QG), yield grade (YG), and Warner-Bratzler shear (WBS) force values (day 1 and 14 postmortem) were evaluated. Relative exit velocity (REV) at feedlot arrival was used as a covariate in mixed models to assess the effects of temperament and interactions with breed type, with means compared at ±1 SD from the mean initial REV. Calm heifers (mean REV minus 1 SD) had 4% greater (P < 0.001) initial BW, 12% greater (P < 0.001) ADG, 8% greater (P < 0.001) DMI, and 4% greater (P < 0.02) G:F than heifers with excitable temperaments (mean REV plus 1 SD). A temperament × breed interaction was detected (P < 0.01) for residual feed intake (RFI). Braford heifers had a more (P < 0.05) negative REV covariate slope (−1.49 ± 0.65) than the other breeds, such that excitable Braford heifers had lower (P < 0.05) RFI than the other breeds with excitable temperaments. Temperament × breed interactions were observed (P < 0.001) for DMI per BW0.75 and bunk visit (BV) duration. Braford heifers had more (P < 0.05) negative REV covariate slopes for both traits than Angus, Brangus, and Simbrah heifers such that excitable Braford heifers consumed less (P < 0.05) DMI per BW0.75 and had less BV duration compared to excitable Angus and Brangus heifers. Calm heifers had 9% greater (P < 0.01) meal duration, and consumed meals that were 22% longer (P < 0.001) and 17% larger (P < 0.001) compared to excitable heifers. Calm heifers had 12% more (P < 0.001) BV events per meal then excitable heifers. Carcasses from calm heifers were 4% heavier (P < 0.05) and had 7% greater (P = 0.05) backfat (BF) depth and tended to have 4% greater (P = 0.07) USDA YG than carcasses from excitable heifers. Additionally, loin steaks from calm heifers had 8% lower (P < 0.05) WBS force than steaks from excitable heifers. Based on a carcass grid with discounts and premiums for HCW, QG, YG, and tenderness, calm heifers returned $62 more (P < 0.01) revenue per animal than excitable heifers. These results demonstrate that heifers with divergent phenotypes for temperament on feedlot arrival differ in their performance, feed efficiency, and feeding behavior patterns, as well as carcass quality and revenue. [ABSTRACT FROM AUTHOR]

In Phase 1 (days 0 to 56) of a two-phase experiment, 81 steers (initial BW = 189 ± 22 kg) were arranged in a generalized randomized block design, allocated to nine pens (nine steers per pen) and assigned to one of three dietary treatments. Treatments consisted of different inclusion rates of Fermenten (FER) in a backgrounding diet fed ad libitum, and were as follows: 0% (CON), 2%, or s FER in the diet DM. Steer was considered the experimental unit, and individual DMI was measured using the GrowSafe system. In Phase 2 (days 57 to 112), treatments were discontinued and steers were relocated to a paddock with free access to a common basal diet, to assess potential residual effects of FER. Effect of treatment was measured on performance, concentration of serum urea nitrogen (SUN), NEFA and glucose, and apparent total tract digestibility of nutrients. On day 56, steers fed 4% FER had lesser (P = 0.01) BW than 2% FER steers. Steers fed CON also tended (P = 0.08) to have greater BW than 4% FER steers. ADG was not different (P = 0.96) between CON and 2% FER steers, whereas steers in the 4% FER treatment had lesser (P ≤ 0.01) ADG than CON and 2% FER. Steers in the 4% FER treatment had lesser (P = 0.04) DMI than CON, and were less feed efficient (P ≤ 0.04) than 2% FER and CON steers. However, DMI as a percentage of the BW did not differ (P = 0.07) across treatments. A treatment effect was observed for final BW on day 112 (P = 0.05), where 4% FER tended (P = 0.07) to have lesser BW than CON. In Phase 2, ADG was not different (P = 0.18) among treatments. However, overall ADG (days 0 to 112) was lesser (P = 0.02) for steers fed 4% FER when compared with CON. There was no difference (P ≥ 0.12) in longissimus muscle area gain or 12th rib fat depth gain. There was a treatment × day interaction for serum concentrations of glucose (P < 0.001), NEFA (P < 0.001), and SUN (P < 0.001). Steers fed 4% FER had greater (P < 0.001) DM, OM, NDF, ADF, and CP apparent total tract digestibility than CON. Similarly, 4% FER steers had greater (P ≤ 0.02) DM, OM, NDF, and ADF digestibility than 2% FER. Results show that although inclusion of FER increased apparent total tract digestibility of nutrients, DMI and overall performance of growing beef cattle were negatively affected, mainly when FER was included at 4% of the diet DM. [ABSTRACT FROM AUTHOR]

The microbial community in the rumen has an important role in the health and production of beef cattle providing up to 70% of the daily energy requirements from the metabolism of otherwise non-digestible dietary carbohydrates. Diet is often the largest determinant of rumen microbiome composition, but it is also affected by host age, genetics, and sex. Performance attributes such as average daily gain and feed efficiency have all been linked to the rumen microbiome and recent studies with relatively small numbers of cattle have also suggested there may be an association with certain beef quality traits such as marbling, which largely determines the carcass value. Thus, the objective of this study was to evaluate the association of the rumen microbiota with carcass merit and beef quality traits. Two hundred steers were slaughtered, and rumen samples were collected immediately post-slaughter. Subsequently, carcass merit and meat quality attributes were evaluated. The rumen microbiota of these animals was then characterized using 16S rRNA gene sequencing. Although we did not identify a significant association between marbling score and the structure of the rumen microbiota (PERMANOVA; P > 0.05), there were significant associations between rumen microbial community structure and commercial weight, dressed weight percentage, drip loss, and intramuscular fat content (P < 0.05). There were also individual bacterial taxa that were correlated with various carcass merit and beef quality traits. Members of the Acidaminococcus genus were negatively associated with both intramuscular fat content and marbling score (P < 0.10) while Coprococcus, Christensenellaceae R-7 group, Lachnospiraceae NK3A20 group, Moryella, and Prevotella were among those genera positively correlated with intramuscular fat content (P < 0.10). Christensenellaceae R-7 group, Lachnospiraceae NK3A20 group, Moryella, and Prevotella were also significantly associated with dressed weight percentage. Commercial weight was positively correlated with the genera Catonella, Prevotellaceae NK3B31 group, Pseudoramibacter, Selenomonas, and Sutterella and negatively associated with Oribacterium and Ruminococcaceae UCG-001 (P < 0.10). Therefore, bacteria within these genera may be ideal targets for future microbiomebased strategies to improve carcass merit and beef quality. [ABSTRACT FROM AUTHOR]

Genetic and phenotypic parameters for feed efficiency, growth, and carcass traits for Australian Angus beef cattle were estimated. Growth traits included birth weight (BWT), 200-d weight (200dWT), 400-d weight (400dWT), and 600-d weight (600dWT). Traits associated with feed efficiency were average daily weight gain (ADG), metabolic midweight, average of daily feed intake (FI), feed conversion ratio (FCR), residual feed intake (RFI), and residual gain (RG). Carcass traits involved were carcass eye muscle area (CEMA), carcass intramuscular fat (IMF), subcutaneous fat depths at the 12th/13th rib (CRIB), rump P8 fat depth (P8FAT), and carcass weight (CWT). For growth traits, heritability estimates ranged from 0.14 ± 0.03 for 200dWT to 0.48 ± 0.06 for 600dWT. For feed efficiency traits, direct heritability estimates for FI, FCR, RFI, and RG were 0.55 ± 0.08, 0.20 ± 0.06, 0.40 ± 0.07, and 0.19 ± 0.06, respectively. High heritability estimates were observed for CEMA, IMF, P8FAT, and CWT of 0.52 ± 0.09, 0.61 ± 0.09, 0.55 ± 0.09, and 0.66 ± 0.09, respectively. Strong positive genetic correlations were found for FI with 200dWT, 400dWT, and 600dWT of 0.68 ± 0.09, 0.42 ± 0.11, and 0.61 ± 0.07, respectively. Weak genetic correlations were observed between RFI and growth traits. For carcass traits, genetic correlations between RFI and CEMA, IMF, CRIB, P8FAT, CWT were −0.19 ± 0.14, 0.31 ± 0.14, 0.18 ± 0.16, 0.24 ± 0.13, and 0.40 ± 0.12, respectively. There was a tendency for low to moderate unfavorable genetic associations between feed efficiency traits, evaluated as RFI and RG, with growth and carcass traits. This implies that selection for RFI would have slight negative impacts on growth and reduce carcass quality. To avoid this, it would be necessary to build selection indices to select feed efficient animals without compromising growth and meat quality. [ABSTRACT FROM AUTHOR]

Selection for feed efficiency (FE) is a strategy to reduce the production costs per unit of animal product, which is one of the major objectives of current animal breeding programs. In pig breeding, selection for FE and other traits traditionally takes place based on purebred pig (PB) performance at the nucleus level, while pork production typically makes use of crossbred animals (CB). The success of this selection, therefore, depends on the genetic correlation between the performance of PB and CB (rpc) and on the genetic correlation (rg) between FE and the other traits that are currently under selection. Different traits are being used to account for FE, but the rpc has been reported only for feed conversion rate. Therefore, this study aimed 1) to estimate the rpc for growth performance, carcass, and FE traits; 2) to estimate rg between traits within PB and CB populations; and 3) to compare three different traits representing FE: feed conversion rate, residual energy intake (REI), and residual feed intake (RFI). Phenotypes of 194,445 PB animals from 23 nucleus farms, and 46,328 CB animals from three farms where research is conducted under near commercial production conditions were available for this study. From these, 22,984 PB and 8,657 CB presented records for feed intake. The PB population consisted of five sire and four dam lines, and the CB population consisted of terminal cross-progeny generated by crossing sires from one of the five PB sire lines with commercially available two-way maternal sow crosses. Estimates of rpc ranged from 0.61 to 0.71 for growth performance traits, from 0.75 to 0.82 for carcass traits, and from 0.62 to 0.67 for FE traits. Estimates of rg between growth performance, carcass, and FE traits differed within PB and CB. REI and RFI showed substantial positive rg estimates in PB (0.84) and CB (0.90) populations. The magnitudes of rpc estimates indicate that genetic progress is being realized in CB at the production level from selection on PB performance at nucleus level. However, including CB phenotypes recorded on production farms, when predicting breeding values, has the potential to increase genetic progress for these traits in CB. Given the genetic correlations with growth performance traits and the genetic correlation between the performance of PB and CB, REI is an attractive FE parameter for a breeding program. [ABSTRACT FROM AUTHOR]

Gluconate salts have been reported to be metabolized by microbes in the gastrointestinal tract to yield butyrate and consequently enhance its functionality. The objective was to evaluate feed intake, growth, and carcass characteristics for heifers fed increasing doses of hydrogenated fat-embedded calcium gluconate (HFCG). Twenty-one 10-mo Simmental × Limousin beef heifers, blocked by initial BW (323 ± 35.3 kg), were individually fed for 206 d (8.72% barley silage, 87.44% dry-rolled barley grain, and 3.84% mineral and vitamin supplement) and used to evaluate three different levels of HFCG (0.0%, 0.09%, and 0.18%; on DM basis through substitution of barley grain). Dry matter intake was determined weekly, and BW was measured at the start and end of the study and every three weeks. Carcass weight was recorded and carcasses were refrigerated for 13 d. The left ribeye (10th to 13th rib) was excised and evaluated by a certified grader from the Canadian Beef Grading Agency. Inclusion of HFCG did not affect DMI (8.29 kg/d; P = 0.87), ADG (1.37 kg/d; P =0.55), or G:F (0.166 kg/kg; P = 0.32). Final live BW and carcass weight averaged 630.9 ± 34.99 and 374.1 ± 10.19 kg and were not affected by treatment (P = 0.73 and 0.65, respectively). Dose of HFCG did not affect carcass characteristics with average values of 7.0 mm for fat thickness (P = 0.46), 104 cm2 for rib-eye area (P = 0.92), 476 for marbling score (P = 0.94), and 50.3% for retail cut yield (P = 0.62). In addition, HFCG did not affect quality grade (P = 0.38) or yield grade (P = 0.86). The present data suggests that the use of HFCG did not affect performance of finishing heifers or carcass quality on beef heifers regardless of dose. [ABSTRACT FROM AUTHOR]

The objective of this research was to test the hypothesis that in ovo feeding of L-arginine (Arg) may improve hatchability and posthatch performance in domestic pigeons (Columba livia). A completely randomized design (n = 3) with an Arg feeding treatment (Arg group, 1.14 mg Arg dissolved in 200 μL of 0.75% NaCl buffered saline as 1% concentration compared to total Arg in the egg), a buffered saline feeding treatment (SC group, 7.5 g NaCl dissolved in 1 L sterile distilled water as the concentration of poultry physiological saline), and a nonfeeding treatment (NC group) was used. Six squabs from each treatment were randomly sampled on day of hatch (DOH), posthatch d 7 (D7), and posthatch d 14 (D14), respectively. Hatchability, hatch time, BW, organ development, and carcass traits were examined. Results showed that in ovo feeding of the Arg solution increased (P < 0.05) the hatchability and advanced (P < 0.05) the hatching time in comparison with those of the other groups. Body weight of pigeon squabs that received Arg in ovo feeding was heavier (P < 0.05) on DOH and D14 than that of the NC group, and a greater (P < 0.05) BW gain from DOH to D14 and D7 to D14 was observed. Three clusters of 12 organs were classified according to the changes of organ indices. Squabs provided the Arg in ovo feeding treatment gained a priority in organ development. The heart index and gizzard index on D7 and the proventriculus index on D14 of squabs receiving Arg in ovo feeding were increased (P < 0.05) compared to those of the other groups. The brain index on DOH, the small intestine index and pancreas index on D7, and the liver index, pancreas index, and spleen index on D14 of squabs fed Arg were higher (P < 0.05) than those of the NC group. The spleen index on D7 and the small intestine index on D14 of squabs provided the Arg feeding treatment were enhanced (P < 0.05) compared with those of the SC group. The semieviscerated carcass weight of squabs receiving Arg was higher (P < 0.05) on D14 than that of other groups. The absolute weight of breast meat yield on D7 and breast meat yield percentage on D7 and D14 were improved (P < 0.05) in the Arg group compared with the NC group. The leg meat percentage on D7 and the carcass weight, eviscerated carcass weight, and absolute weight of breast meat yield on D14 were increased (P < 0.05) in the Arg group compared with those of the SC group. The results of this study indicate that in ovo feeding of pigeon embryos with Arg may have beneficial effects on squab hatch performance and early posthatch performance. [ABSTRACT FROM AUTHOR]

Sixty Duroc × Large White × Landrace pigs with an average initial BW of 77.1 ± 1.3 kg were used to investigate the effects of dietary supplementation with arginine and glutamic acid on growth performance, carcass traits, and meat quality in growing-finishing pigs. The animals were randomly assigned to 1 of 5 treatment groups (12 pigs/group, male:female ratio 1:1). The pigs in the control group were fed a basal diet (basal diet group), and those in the experimental groups were fed the basal diet supplemented with 2.05% l-alanine (isonitrogenous group), 1.0% l-arginine (Arg group), 1% glutamic acid + 1.44% l-alanine (Glu group), or 1.0% l-arginine + 1.0% glutamic acid (Arg+Glu group). After a 60-d period of supplementation, growth performance, carcass traits, and meat quality were evaluated. The results showed no significant differences (P > 0.05) in growth performance and carcass traits of the pigs in the Arg group relative to the basal diet group; however, the longissimus dorsi (LD) muscle and back fat showed a decrease (P < 0.05) in the percentage of SFA. In the Glu group, the final BW, phase 1 (d 1 to 30) and phase 2 (d 31 to 60) ADFI, and average back fat thickness of the pigs decreased (P < 0.05) by 7.14%, 23.43%, 8.03%, and 33.88%, respectively, when compared with the basal diet group. Dietary Arg+Glu supplementation had no effect (P > 0.05) on the final BW, phase 2 ADFI, and average daily weight gain in pigs but decreased (P < 0.05) their phase 1 ADFI, average back fat thickness, and percentage of SFA in the LD muscle and back fat, and increased (P < 0.05) the i.m. fat (IMF) content of the LD and biceps femoris muscles when compared with the basal diet group. Furthermore, a 16% decrease in yellowness (b* value; P < 0.05) was observed in the Arg+Glu group pigs when compared with the isonitrogenous group. These findings suggest that dietary supplementation with both Arg and Glu beneficially increases the IMF deposition and improves the meat color and fatty acid composition without affecting growth performance and s.c. fat in pigs, providing a novel strategy to enhance meat quality in growing-finishing pigs. [ABSTRACT FROM AUTHOR]

The Mef2B gene (myocyte enhancer factor 2B) encodes a transcription factor belonging to the MEF2 family that plays an important role in myogenesis by transcriptional regulation of genes involved in skeletal muscle growth and development. Despite the established importance of the Mef2 factors in the muscular growth and development, the temporalspatial expression and biological function of Mef2B have not been reported in cattle. The aim of this study was to analyze the level of Mef2B expression in the developing longissimus dorsi muscle (LM) of 4 cattle breeds (Polish Holstein-Friesian [HF], Limousine [LIM], Hereford [HER], Polish Red [PR]), differing in terms of meat production and utility type, at 6, 9, and 12 mo of age. The Mef2B genetic polymorphism and expression patterns in 6 tissues (heart, spleen, liver, semitendinosus muscle [ST], gluteus medius muscle [GM], and LM) were also investigated. The results showed that Mef2B mRNA was expressed at a high level in adult skeletal and cardiac muscles. Moreover, Mef2B expression was markedly greater in the GM than in the LM (P < 0.05) and ST (P < 0.01). An age-dependent and breed-specific comparison of Mef2B mRNA level in skeletal muscle of HF, LIM, HER, and PR bulls showed that age was significant differentiating factor of Mef2B transcript/ protein abundance in the LM of HER and LIM (P < 0.001) compared to HF and PR, for which the differences in Mef2B mRNA level were not significant (P > 0.05). Regarding the breed effect on the Mef2B expression, significantly greater Mef2B mRNA/protein level was noticed in the LM of 9 and 12 mo-old HER than of LIM (P < 0.01), HF (P < 0.001), and PR (P < 0.001). Four novel SNP, namely, HQ591462:g.909A > G (promoter), JX065116:g.3867T > C (exon 7), JX065116:g.4359G > C (exon 8), and JX065116:g.4546G > A (3’UTR), were identified. We found that Mef2B 3’UTR variant, situated within the seed region of the miR-5187–3p and miR-6931–5p binding sites, was associated with the level of Mef2B mRNA/protein in LM of 12-mo-old HF bulls. In addition, we observed a significant association between some carcass quality traits, including meat and carcass fatness quality traits, and various Mef2B 3’UTR genotypes in the investigated population of HF cattle. Our finding provides new evidence of the Mef2B significant role in the postnatal muscle growth and development in cattle, and indicates that Mef2B can be a promising molecular marker for carcass quality-related traits in adult cattle. [ABSTRACT FROM AUTHOR]

The aim of our study was to compare different validation methods with respect to their impact on validation results and to evaluate the feasibility of genomic selection in the German Landrace population of the Bavarian herdbook. For this purpose, a sample of 337 boars and 1,676 sows was genotyped with the Illumina PorcineSNP60 BeadChip. Conventional BLUP breeding values for fertility, growth, carcass, and quality traits were deregressed and used as phenotypes in genomic BLUP. The resulting genomic breeding values were also blended with information from the full conventional breeding value estimation to include information from nongenotyped parents. Subsequent validation used forward prediction, realized reliabilities, and theoretical reliabilities. The results indicate that the validation methods showed a relatively large effect on in the displayed reliability levels in our study: forward prediction reliabilities were found to be much lower than the conventional parent-average reliabilities whereas corresponding realized and theoretical reliabilities were found substantially greater. Theoretical reliabilities appear to be the most consistent validation approach tested in our study, because they avoid the use of proxy variables. Generally, our results suggest a substantial potential for a genomic selection implementation for the Bavarian herdbook by using both sows and boars. Theoretical genomic reliabilities of direct genomic values of selection candidates were, on average, 31 to 36% greater than the conventional parent average reliabilities. However, the inclusion of residual information from conventional breeding values had only a marginal effect on reliabilities. [ABSTRACT FROM AUTHOR]

The objective of this study was to assess the nutritional value of barley grain differing in diastatic power (DP; high vs. low; a malt trait) and processing index (PI; 75 vs. 85). One hundred sixty Angus x Hereford crossbred yearling steers (467 ± 38 kg; 144 intact and 16 rumen cannulated) were used in a complete randomized 2 x 2 factorial experiment. Steers were assigned to 16 pens, 8 of which were equipped with the GrowSafe system to measure individual feed intake. Cannulated steers (2 per pen) were randomly assigned to the 8 GrowSafe pens. Diets consisted of high- or low-DP barley grain (80.0% of diet DM) processed to an index of either 75 or 85% (PI-75 and PI-85, respectively). Ruminal pH in cannulated steers was measured over four 5-d periods using indwelling electrodes. Fecal samples were collected every 28 d from the rectum of each steer to assess digestibility using AIA as a marker. No differences (P > 0.10) in rumen pH were observed among cattle as measured by the indwelling pH meters. However, lower (P < 0.05) rumen pH was observed for steers fed low- as opposed to high-DP barley in rumen samples collected just prior to feeding and measured in the laboratory. Intake of DM and OM were not affected (P ≥ 0.24) by DP but were lower (P < 0.01) with more severe processing (PI-75 vs. PI-85). Low-DP barley tended to exhibit higher (P = 0.09) total tract DM digestibility than high- DP barley. Steers fed PI-75 barley also had higher (P = 0.06) G:F and NEg. Digestibility of DM, OM, CP, NDF, and starch was higher (P < 0.05) for PI-75 barley than for PI-85 barley. Low-DP barley increased (P < 0.05) carcass dressing percentage by 0.5% compared with high-DP barley, with a lower PI tending to increase (P = 0.06) rib eye area. Compared with steers fed high- DP diets, steers fed low-DP diets had more (P = 0.01) total (41.7 vs. 19.4%) and severe liver abscesses (22.2 vs. 9.7%). Results suggest that although low-DP barley increased liver abscesses, differences in DP did not alter digestion or growth performance but low-DP barley did improve dressing percentage. Barley with different DP responded similarly to processing, with more intensive processing (PI-75) of barley improving starch digestion, feed efficiency, and NEg without negatively affecting rumen pH. [ABSTRACT FROM AUTHOR]

A combination of yeast and chromium propionate (Y+Cr) was added to the diets of crossbred finishing steers (n = 504; 402 kg ± 5.76 initial BW) to evaluate impact on feedlot performance and carcass traits. We hypothesized supplementation of Y+Cr would increase growth of feedlot steers. Steers with initial plasma glucose concentrations ≤6.0 mM were stratified by initial BW and randomly allocated, within strata, to receive 0 (control) or 3.3 g/d Y+Cr. Steers were further divided into heavy and light weight blocks with 6 pens/diet within each weight block. Cattle were housed in dirt-surfaced pens with 21 steers/pen and had ad libitum access to feed. Body weights were measured at 21-d intervals. Blood samples were collected on d 49 and 94 from a subset of steers (5/pen) for analyses of plasma glucose and lactate concentrations. At the end of the finishing phase, animals were weighed and transported 450 km to an abattoir in Holcomb, KS. Severity of liver abscesses and HCW were collected the day of harvest, and after 36 h of refrigeration, USDA yield and quality grades, LM area, and 12th rib subcutaneous fat thickness were determined. There were no treatment ? time ? weight block interactions (P > 0.05) and no treatment ? block interaction for ADG, DMI, or final BW (P ≥ 0.06), but a treatment ? block interaction (P = 0.03) was observed for G:F, in which control, light cattle had poorer efficiency compared with other groups. Treatment ? weight group interactions were observed for overall yield grade and carcasses that graded yield grade 1 (P ≤ 0.04). Light steers supplemented with Y+Cr had decreased overall yield grade and increased percentage of carcasses grading yield grade 1 compared with their control counterparts, with no differences observed for heavy steers. Regardless of weight group, a greater percentage of carcasses from steers supplemented with Y+Cr graded yield grade 2 (P = 0.03) and fewer carcasses from steers supplemented Y+Cr graded yield grade 3 (P < 0.01) than control steers. No interactions or effects of treatment were detected for other carcass measurements (P ≥ 0.07). There were no treatment ? weight group interactions or effects of treatment for plasma glucose or lactate concentrations on d 49 or 94 (P > 0.10). Overall, yeast in combination with chromium propionate may improve feed efficiency and decrease yield grade of light cattle but had no effect on remaining carcass traits and blood constituents. [ABSTRACT FROM AUTHOR]

The effects of lasalocid on rumen measures, beef and dairy performance, and carcass traits were evaluated using meta-analysis. Meta-regression was used to investigate sources of heterogeneity. Ten studies (20 comparisons) were used in the meta-analysis on rumen measures. Lasalocid increased total VFA and ammonia concentrations by 6.46 and 1.44 mM, respectively. Lasalocid increased propionate and decreased acetate and butyrate molar percentage (M%) by 4.62, 3.18, and 0.83%, respectively. Valerate M% and pH were not affected. Meta-regression found butyrate M% linearly increased with duration of lasalocid supplementation (DUR; P = 0.017). When >200 mg/d was fed, propionate and valerate M% were higher and acetate M% was lower (P = 0.042, P = 0.017, and P = 0.005, respectively). Beef performance was assessed using 31 studies (67 comparisons). Lasalocid increased ADG by 40 g/d, improved feed-to-gain ratio (F:G) by 410 g/kg, and improved feed efficiency (FE; combined measure of G:F and the inverse of F:G). Lasalocid did not affect DMI, but heterogeneity in DMI was influenced by DUR (P = 0.004) and the linear effect of entry BW (P = 0.011). The combination of ≤100 vs. >100 d DUR and entry BW ≤275 vs. >275 kg showed that cattle ≤275 kg at entry fed lasalocid for >100 d had the lowest DMI. Heterogeneity of ADG was influenced by the linear effect of entry BW (P = 0.028) but not DUR. Combining entry BW ≤275 vs. >275 kg and DUR showed that cattle entering at >275 kg fed ≤100 d had the highest ADG. The FE (P = 0.025) and F:G (P = 0.015) linearly improved with dose, and entry BW >275 kg improved F:G (P = 0.038). Fourteen studies (25 comparisons) were used to assess carcass traits. Lasalocid increased HCW by 4.73 kg but not dressing percentage, mean fat cover, or marbling score. Heterogeneity of carcass traits was low and not affected by DUR or dose. Seven studies (11 comparisons) were used to assess dairy performance but the study power was relatively low and the evidence base is limited. Lasalocid decreased DMI in total mixed ration-fed cows by 0.89 kg/d but had no effect on milk yield, milk components, or component yields. Dose linearly decreased DMI (P = 0.049). The DUR did not affect heterogeneity of dairy measures. This work showed that lasalocid improved ADG, HCW, FE, and F:G for beef production. These findings may reflect improved energy efficiency from increased propionate M% and decreased acetate and butyrate M%. Large dairy studies are required for further evaluation of effects of lasalocid on dairy performance. [ABSTRACT FROM AUTHOR]

To get insights into selection criteria for feed efficiency, 2 rabbit lines have been created: the ConsoResidual line was selected for residual feed intake (RFI) with ad libitum feeding and the ADGrestrict line was selected for ADG under restricted feeding. The aim of the present study was to evaluate the impact on carcass and meat quality of the genetic selections. This comparison was performed using 2 different feeding strategies corresponding to the selection design. Carcass and meat quality traits were recorded for the 3 lines (ConsoResidual, ADGrestrict, and an unselected control [generation 0 {G0}]) in the 2 feeding systems (ad libitum and restricted) for 163 animals. Concerning the line effect, the BW at 63 d old was higher for the ADGrestrict line compared with the G0 and ConsoResidual lines (P < 0.0001). There was no line effect on the gastrointestinal tract. The rabbits did not exhibit a different carcass yield but showed different carcass traits. Indeed, the ConsoResidual rabbits had a higher hind leg yield (P < 0.0001) but no difference in the meat-to-bone ratio of the hind leg. On the contrary, the ADGrestrict line had a higher proportion of forelegs plus thoracic cage (P = 0.03). We also found lower perirenal (P < 0.0001) and scapular fat yields (P < 0.0001) in ConsoResidual rabbits. The ADGrestrict line had an intermediate perirenal fat yield compared with the other 2 lines. The G0 line always exhibited higher fat yields. Concerning meat quality, the ConsoResidual rabbits showed a lower ultimate pH (P < 0.0001) and higher water loss (drip and cooking loss; P < 0.002) compared with the G0 and ADGrestrict rabbits. The feeding level had a strong effect on the gastrointestinal tract (P = 0.0004) and the carcass yield (P = 0.001). The latter was decreased in restricted rabbits. The effects of feeding strategy on meat quality were detrimental in the case of restricted feeding. Even if the ultimate pH was slightly higher in restricted rabbits (P = 0.0002), the carcass chilling loss (P = 0.0005) and the drip loss during 6 d (P < 0.0001) were higher. The selection on ADG with restricted access to feed seems to be less adversely correlated with carcass traits and meat quality traits but it leads to an increase in the live weight of the rabbits. Adversely, the selection on RFI, without affecting growth rate, would not modify age at slaughter because growth rate is not affected, but it might induce detrimental effects on meat quality. [ABSTRACT FROM AUTHOR]

The aim of the present study was to evaluate the impact of zilpaterol hydrochloride (ZH; 0 or 10 mg/lamb daily) and soybean oil (SBO; 0 or 6%) supplementation on feedlot performance, carcass traits, and wholesale cut yield of 32 Dorper × Pelibuey ewe lambs (30.55 ± 2. 57 kg of initial BW). Lambs were blocked by BW and randomly assigned to treatments under a randomized complete block design with a 2 × 2 factorial arrangement. After a 34-d feeding period, all ewes were slaughtered. No ZH × SBO interactions were detected (P ≥ 0.11) for the variables evaluated. In the overall feeding period and first 17 d of experiment, feedlot performance was not affected (P ≥ 0.26) by ZH supplementation, but from d 18 to 34, ZH increased (P ≤ 0.03) total gain, ADG, and G:F without affecting DMI (P = 0.58). Also, ZH increased (P ≤ 0.02) HCW, cold carcass weight, dressing percentage, LM area, and leg perimeter. Lung weight as percentage of final BW decreased (P = 0.05) whereas other noncarcass components and wholesale cut yields were not affected (P ≥ 0.06) by ZH supplementation. Inclusion of SBO did not affect (P ≥ 0.08) feedlot performance or wholesale cut yields. The LM pH at 24 h postmortem as well as liver and peritoneum percentages were decreased (P ≤ 0.05) by SBO supplementation, but no other carcass characteristics or noncarcass components were affected (P ≥ 0.08) by SBO. In conclusion, feedlot performance and carcass characteristics were not altered by the interaction of ZH × SBO. However, ZH alone increased the growth of ewes during the last 17 d of the feeding period. Likewise, carcass characteristics of economic importance (i.e., HCW, dressing percentage, LM area, and leg perimeter) increased with ZH supplementation. In general, feedlot performance, carcass traits, and wholesale cut yields were not altered by including 6% of SBO in the finishing diet of ewe lambs. [ABSTRACT FROM AUTHOR]

Selection emphasis on linear body measurement traits associated with increased lifetime production efficiency may be beneficial to decrease culling and increase profitability in both dairy and beef industry. The importance of knowledge of associations between body measurement and carcass traits is essential to obtain indices in order to increase the response to selection and incorporate these traits in designing a breeding program. Hence, the objective of the present study was to estimate variance components and genetic parameters for linear body measurement and carcass traits in the Hanwoo cattle. Backfat thickness (BFT), carcass weight (CWT), eye muscle area (EMA), and marbling score (MS) at around 24 months of age considered as carcass traits and analyzed 10 body measurement traits at yearling age of Hanwoo were body height (BH), body length (BL), chest depth (CD), chest girth (CG), chest width (CW), hip height (HH), hip width (HW), rump length (RL), rump width (RW), and thurl width (TW). The (co)variance components were estimated using AI-REML in a series of bivariate analyses, which were implemented by the AIREMLF90 software. Moderate to high heritability estimates were found for the carcass traits, which were 0.32, 0.46, 0.50, and 0.61 for CWT, EMA, BFT, and MS, respectively. Heritability estimates for linear body measurement were low to medium, ranging from 0.12 to 0.37. The body measurement traits exhibited moderate to relatively high genetic correlations with CWT, while the genetic correlations of body measurement with the three other carcass traits were very low. The results of this study demonstrated the favorable and positive genetic correlations between linear body measurement and carcass weight, indicating that selection on these traits can be effective in Hanwoo breeding programs without having unfavorable effects on other carcass traits. [ABSTRACT FROM AUTHOR]

Chronic heat stress (HS) is a major concern affecting pig growth performance and metabolism, with potential consequences on carcass and meat quality traits. The objective of this study was to assess the influence of prenatal (PE) and growing (GE) thermal environments, and their combination, on muscle metabolism, carcass characteristics, and pork quality. From 6 to 109 d of gestation, 12 sows (1 per block) were kept under thermoneutral (TN) conditions (cyclic 18 to 24 °C; PTN) and 12 sows under chronic HS (cyclic 28 to 34 °C; PHS). Two female offspring per sow were selected based on body weight at weaning, for a total of 48 female pigs (12 blocks of 2 sisters from each PE), and one sister was placed in each GE. Gilts were housed from 82 to 140 d of age under cyclic GTN (18 to 24 °C; n = 24) or GHS (28 to 34 °C; n = 24) environments. Data were analyzed using a mixed model including PE, GE, and PE × GE interaction as main effects, and sire, sow within PE, pen within PE × GE, and slaughter day (for plasma, muscle, and meat traits) as random effects. No significant PE × GE interaction was found on any trait under study (P ≥ 0.05). Prenatal HS did not affect growth performance and carcass traits (P ≥ 0.05). Compared with GTN, GHS pigs had lower average daily feed intake, average daily gain, and hot carcass weight (P < 0.01), but similar carcass lean meat content (P ≥ 0.05). Prenatal HS had scarce effects on pork quality, with only higher a* and C* values (P < 0.05) in the Gluteus superficialis. Growing HS led to a higher pH 24 h (P < 0.05) in the Longissimus thoracis et lumborum (LTL) and ham muscles, and higher meat quality index in the ham muscles. In contrast, quality traits of the Semispinalis capitis (SC) were not affected by either PE or GE (P > 0.05). Except a tendency for a higher citrate synthase activity in the SC (P = 0.065), PHS did not affect muscle metabolism. Growing HS induced muscle-specific metabolic responses, with reduced glycolytic potential (P < 0.01) and metabolic enzyme activities (P < 0.05) in the glycolytic LTL, but not in the oxidative SC (P > 0.05). Plasma glucose content at slaughter was lower in the GHS compared with GTN pigs (P = 0.002), indicating an altered energy metabolism in pigs under GHS. Altogether, growing HS altered growth without affecting carcass traits, but improved technological quality of loin and ham. Prenatal HS, alone or combined with GHS, had limited or even no effect on carcass and pork quality., (© The Author(s) 2023. Published by Oxford University Press on behalf of the American Society of Animal Science. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

The aims of this study were to estimate covariance components for BW at 270 d (BW270) and carcass and ham quality traits in heavy pigs using models accounting for social effects and to compare the ability of such models to fit the data relative to models ignoring social interactions. Phenotypic records were from 9,871 pigs sired by 293 purebred boars mated to 456 crossbred sows. Piglets were born and reared at the same farm and randomly assigned at 60 d of age to groups (6.1 pigs per group on average) housed in finishing pens, each having an area of 6 m2. The average additive genetic relationship among group mates was 0.11. Pigs were slaughtered at 277 ± 3 d of age and 169.7 ± 13.9 kg BW in groups of nearly 70 animals each. Four univariate animal models were compared: a basic model (M1) including only direct additive genetic effects, a model (M2) with nonheritable social group (pen) effects in addition to effects in M1, a model (M3) accounting for litter effects in addition to M2, and a model (M4) accounting for social genetic effects in addition to effects in M3. Restricted maximum likelihood estimates of covariance components were obtained for BW270; carcass backfat depth; carcass lean meat content (CLM); iodine number (IOD); and linoleic acid content (LIA) of raw ham subcutaneous fat; subcutaneous fat depth in the proximity of semimembranosus muscle (SFD1) and quadriceps femoris muscle (SFD2); and linear scores for ham round shape (RS), subcutaneous fat (SF), and marbling. Likelihood ratio tests indicated that, for all traits, M2 fit the data better than M1 and that M3 was superior to M2 except for SFD1 and SFD2. Model M4 was significantly better than M3 for BW270 (P < 0.001) and CLM, IOD, RS, and SF (P < 0.05). The contribution of social genetic effects to the total heritable variance was large for CLM and BW270, ranging from 33.2 to 35%, whereas the one for ham quality traits ranged from 6.8 (RS) to 11.2% (SF). Direct and social genetic effects on BW270 were uncorrelated, whereas there was a negative genetic covariance between direct and social effects on CLM, IOD, RS, and SF, which reduced the total heritable variance. This variance, measured relative to phenotypic variance, ranged from 21 (CLM) to 54% (BW270). Results indicate that social genetic effects affect variation in traits relevant for heavy pigs used in dry-cured hams manufacturing. Such effects should be exploited and taken into account in design of breeding programs for heavy pigs. [ABSTRACT FROM AUTHOR]

Forty-four merino lambs (6 to 8 wk old; BW 15.6 ± 0.21 kg) were used to study the effect of adding different proportions of sunflower soap stock (SS) to pelleted total mixed ration (TMR) for fattening lambs on feed intake, animal growth and dressing percentage, ruminai fluid characteristics, and blood acid-base parameters. Lambs were assigned to 1 of 4 experimental groups (11 lambs per group), each randomly assigned to 1 dietary treatment: 00SS (0 g SS/kg TMR pellet), 15SS (15 g SS/kg TMR pellet), 30SS (30 g SS/kg TMR pellet), and 60SS (60 g SS/kg TMR pellet). Lambs were individually fed the corresponding diet ad libitum. On d 19 to 23, total feces were collected and sampled from 4 lambs per group. When lambs reached 27 kg BW, they were slaughtered. Dry matter intake, ADG, and length of fattening period were not affected by the dietary treatment (P > 0.10). Animals in the 30SS group tended to show the best G:F values (P < 0.10). Dressing percentage tended to linearly decrease as SS increased (P < 0.10). Animals in the 60S S groups showed the lowest DM and fiber digestibility values (P < 0.05). Total VFA contents in ruminai fluid were not affected (P > 0.10), but the propionate proportion linearly increased (P < 0.05), and the acetate to propionate ratio tended to decrease with SS supplementation. Increasing dietary content of SS linearly decreased the cold carcass weight (P < 0.05) but did not affect other measured carcass characteristics. Ruminai fluid pH tended to decrease (P <0.10) and mucosa color decreased as SS increased in the TMR (P < 0.05). Blood pH and Na concentration increased (P < 0.05), whereas the anion gap, CO2 pressure, and K concentration linearly decreased (P < 0.05) as SS increased. Including more than 30 g SS/kg TMR in the diet for fattening lambs reduces DM and fiber digestibility without affecting feed intake and ADG. The acidotic rumen conditions that induced a darkening of rumen mucosa were counteracted by blood acid-base parameters. The optimum level of inclusion seems to be 30 g SS/kg TMR. [ABSTRACT FROM AUTHOR]

This study aimed to compare the growth performances and carcass characteristics of tropical-breed steers reared in 2 contrasted feeding systems (indoor vs. pasture) and slaughtered at different ages (early vs. late). A total of 309 Creole steers (growing at an initial BW of 173 ± 3 kg and an initial age of 252 ± 4 d) were used over a continuous 12-yr study. Indoor steers were housed in a cattle shed, fed fresh-cut grass plus concentrate, and slaughtered at 14.5 or 17.1 ±0.1 mo of age. Pasture steers were pasture grazed without supplemental feed, and slaughtered at 17.6 and 21.2 ± 0.1 mo of age. Indoor-fed steers had a greater ADG (786 vs. 517 ± 29 g-d-1 ; P < 0.0001 ) and more carcass fat (164 vs. 145 ± 4.5 g-kg-1; P = 0.001) than pasture-fed steers. Late-slaughtered steers had decreased ADG (630 vs. 673 ± 27 g-d-1 ; P = 0.001) but greater dressing percentages (hot dressing percentage = 55.7 vs. 54.7 ± 0.34%; chilled dressing percentage = 54.5 vs. 53.4 ± 0.34%; P < 0.0001) than early-slaughtered steers. The interaction between feeding system and slaughter age was significant for carcass tissue composition. Whole-carcass muscle content was greater in late-slaughtered steers than early-slaughtered steers, especially in pasture-fed steers (720 vs. 698 ± 6.0 g.kg-1; P < 0.0001), but less so in indoor-fed steers (707 vs. 700 ± 5.9 g.kg-1; P = 0.046). Furthermore, increasing slaughter age had no effect on carcass fat in indoor-fed steers (162 vs. 166 ± 4.8 g.k-1; P = 0.342), but decreased carcass fat in pasture-fed steers (150 vs. 140 ± 5.0 g.kg-1; P = 0.014). The results showed that slaughter age and feeding system are 2 major factors that independently affect most of the growth and carcass traits of tropical-breed steers but jointly influence tissue deposition. Our study found that in tropical-breed steers that are grazing, late slaughtering grazing steers increased carcass muscle content without extra fat, thus yielding a carcass quality better suited to consumer choices. [ABSTRACT FROM AUTHOR]

An experiment consisting of two 4-wk trials was conducted to determine Lys use for growth and carcass traits in barrows and gilts fed individually or in groups. One hundred twelve growing pigs (56 barrows and 56 gilts; average initial BW of 18.6 kg) were used in each trial. Pigs were fed individually or in groups of 3. There were 28 pigs individually penned, and 84 pigs in 28 pens (3 pigs/pen). There were 2 replications per treatment in each trial for a total of 4 replications. Dietary treatments consisted of a corn-soybean meal (SBM) basal diet (0.48% Lys) and diets containing 0.56%, 0.65%, and 0.74% standardized ileal digestible (SID) Lys that were achieved by adding Lys to the basal diet from either SBM or crystalline source as L-Lys HCL (CLys). At the end of each trial, all pigs were scanned using real-time ultrasound to determine 10th-rib back fat depth and LM area, and fat-free lean gain (FFLG) was calculated. Blood samples were tak-en from all pigs weekly to determine plasma urea N (PUN). Pigs fed CLys and Lys from SBM were not dif-ferent in final BW, ADG, ADFI, or G:F. The ADG and G:F increased linearly (P< 0.01) as dietary Lys concen-tration increased. The SID Lys intake increased linearly (P <0.01) as dietary Lys concentration increased and was not different when comparing pigs fed diets with CLys or SBM. The amount of SID Lys required per unit of growth or BW gain increased linearly (about 13 to 15.50 g/kg) in pigs fed either CLys or SBM Lys. Pigs fed individually had a greater (P < 0.05) ADG (0.59 vs. 0.57 kg) and ADFI (1.36 vs. 1.29 kg) than pigs fed in groups. The SID Lys intake was greater (P < 0.05) in pigs fed individually in comparison with pigs fed in a group (8.51 vs. 8.06 g/d). Fat-free lean gain and LM area increased (P <0.01) as dietary Lys concentration increased regardless of Lys source. Pigs fed CLys diets had a greater (P < 0.05) LM area than pigs fed SBM at 0.74% SID Lys. Gilts had a greater (P <0.01) LM area (14.28 vs. 13.58 cm2) and FFLG (264 vs. 245 g/d) than barrows. Pigs fed individually with CLys had less (P <0.01) PUN than pigs fed Lys from SBM. Barrows fed individually had less (sex x feeding method, P < 0.01) PUN than gilts (26.75 vs. 29.32 g/100 mL). The results indicate that Lys from SBM-bound and CLys source were utilized similarly for growth and carcass traits regardless of sex or feeding method. [ABSTRACT FROM AUTHOR]

The use of sexed semen at dairy farms has improved heifer replacement over the last decade by allowing greater control over the number of retained females and enabling the selection of dams with superior genetics. Alternatively, beef semen can be used in genetically inferior dairy cows to produce crossbred (beef x dairy) animals that can be sold at a higher price. Although crossbreeding became profitable for dairy farmers, meat cuts from beef x dairy crosses often lack quality and shape uniformity. Technologies for quickly predicting carcass traits for animal grouping before harvest may improve meat cut uniformity in crossbred cattle. Our objective was to develop a deep learning approach for predicting ribeye area and circularity of live animals through 3D body surface images using two neural networks: 1) nested Pyramid Scene Parsing Network (nPSPNet) for extracting features and 2) Convolutional Neural Network (CNN) for estimating ribeye area and circularity from these features. A group of 56 calves were imaged using an Intel RealSense D435 camera. A total of 327 depth images were captured from 30 calves and labeled with masks outlining the calf body to train the nPSPNet for feature extraction. Additional 42,536 depth images were taken from the remaining 26 calves along with three ultrasound images collected for each calf from the 12/13th ribs. The ultrasound images (three by calf) were manually segmented to calculate the average ribeye area and circularity and then paired with the depth images for CNN training. We implemented a nested cross-validation approach, in which all images for one calf were removed (leave-one-out, LOO), and the remaining calves were further divided into training (70%) and validation (30%) sets within each LOO iteration. The proposed model predicted ribeye area with an average coefficient of determination (R2) of 0.74% and 7.3% mean absolute error of prediction (MAEP) and the ribeye circularity with an average R2 of 0.87% and 2.4% MAEP. Our results indicate that computer vision systems could be used to predict ribeye area and circularity in live animals, allowing optimal management decisions toward smart animal grouping in beef x dairy crosses and purebred., (© The Author(s) 2022. Published by Oxford University Press on behalf of the American Society of Animal Science. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

This study was conducted to compare the effects of mannanoligosaccharides (MOS) and antibiot-ics as a dietary supplement on ADG, ADFI, G:F, and feed nutrient digestibility of rabbits during the fatten-ing period, as well as on carcass traits and meat quality. A total of 512, sixty-day-old hybrid Hyla rabbits were randomly divided into 4 treatment groups based on BW and sex. The 4 treatment groups consisted of a control group and 3 MOS groups. The control group was fed a diet that contained apramycin (50 mg/kg), but diets for the 3 MOS groups contained 0.5, 1.0, or 1.5 g/kg of MOS instead of apramycin. The rabbits were fed exper-imental diets for 22 d and all rabbits were slaughtered at the end of the experiment when they were 82 d old. Individual BW and feed intake per cage were recorded weekly for 32 cages randomly chosen per group (64 rabbits) to calculate ADG, ADFI, and G:F. The appar-ent digestibility values of OM, CP, ether extract, crude fiber, NDF, ADF, cellulose, and hemicellulose were measured using AIA as an inert marker. Carcass data were collected from 16 randomly chosen rabbits (8 males and 8 females) per group. The control group had less G:F (P < 0.001) than the MOS groups and a linear increase (P < 0.001) in G:F was observed as the con- centration of MOS increased from 0.5 to 1.0 and 1.5 g/ kg. The apparent digestibility of DM, OM, crude fiber, NDF, ADF, cellulose, and hemicellulose increased (quadratic, P < 0.05) as the concentration of MOS in the diets increased. The apparent digestibility of DM, OM, CP, crude fiber, NDF, ADF, cellulose, and hemicellu-lose was also greater (P < 0.05) in the diets containing MOS than in the control diet and the digestibility of these nutrients was greater (P < 0.05) in the diet con-taining 1.5 g/kg of MOS compared with the control diet. The concentration of palmitic acid, stearic acid, and SFA was greater (P < 0.05) in the meat from rab-bits fed the control diet than rabbits fed the MOS diets. The concentration of stearic acid decreased (quadratic, P < 0.05) in the meat of rabbits as the concentration of MOS in the diet increased. Meat from rabbits fed diets containing MOS also had greater contents of oleic acid (P <0.05) and MUFA (P < 0.001) than those rabbits fed the diet containing apramycin. The thrombogenic index was greater (P < 0.05) in the meat from the control group rabbits than the MOS group rabbits. In conclu-sion, the inclusion of MOS in diets fed to rabbits during the fattening period may improve G:F and modify the fatty acid profile of meat [ABSTRACT FROM AUTHOR]

To evaluate terminal-sire breeds, harvest BW, prefabrication carcass measurements, and organ weights were evaluated over 3 yr for 518 crossbred weather lambs (Ovis aries). Lambs were produced by single-sire matings of 22 Columbia, 22 USMARC-Composite (Composite), 21 Suffolk, and 17 Texel rams to adult Rambouillet ewes. Lambs were raised to weaning under an extensive western rangeland production system and finished in a feedlot on a high-energy finishing diet. Wethers were randomly assigned to be harvested at an average BW of 54.4, 61.2, or 68.0 kg and then transported to The Ohio State University abattoir for harvest. Wether BW was recorded before transport (off-test BW) and before harvest. Prefabrication carcass measurements and organ weights were recorded either after harvest or after an approximate 24-h chill. At comparable numbers of days on feed, Suffolk-sired lambs had heavier (P < 0.01) off-test BW, harvest BW, HCW, chilled carcass weight (CCW), and kidney weights than lambs sired by the other breeds. Suffolk-sired lambs had more (P < 0.01) kidney-pelvic fat than did Columbia-sired lambs; Composite- and Texel-sired lambs were intermediate and did not differ (P > 0.06) from the other crossbred lambs. Texel- and Suffolk-sired lambs had larger LM area and greater conformation scores than Columbia-sired lambs (P < 0.03). Texel-sired lambs had greater (P < 0.01) body wall thickness, quality grades, and leg scores than Columbia-sired lambs. Composite-and Suffolk-sired lambs did not differ from each other or from lambs sired by any other breed for body wall thickness (P > 0.18) and were intermediate for quality grades and leg scores. Sire breed did not affect (P > 0.05) shipping shrink, dressing percentage, pelt weight, liver weight, and fat depth. Adjusting data to a comparable off-test BW or CCW modified sire breed rankings for some measurements. Texel-sired lambs were equal or superior to lambs sired by other breeds for HCW, CCW, dressing percentage, pelt weight, LM area, quality grade, and leg and conformation scores. However, Texel-sired lambs also had values for kidney-pelvic fat weight, fat depth, and body wall thickness that were equal to or greater than those of lambs sired by the other breeds, indicating increased fatness at comparable BW. Producers can use these results to select terminal-sire sheep breeds that will complement their production system and improve market lamb value. [ABSTRACT FROM AUTHOR]

The article focuses on a study to determine heterosis and breed genetic effects for carcass quantity, quality and palatability traits of steers produced from striaghtbred and crossbred of Romosinuano, Brahman and Angus bulls and cows. It informs that Romosinuano steers had some quality and palatability advantage relative to Brahman but did not provide a clear superior alternative to Brahman for U.S. producers. It discusses the results which states that Romosinuano-Angus estimates was smallest.

The objectives of this experiment were to determine the effects of 2 different breeds (BR), Boer and Kiko, and 4 post-weaning harvest ages (HA; Days 0, 29, 56, and 85) on growth, carcass traits, blood metabolites, and lipogenic gene expression. Forty-eight goat (Capra hircus) kids (BW = 23.9 ± 1.50 kg; 3 to 4 mo) were used in a 2 x 4 factorial arrangement of treatments. Goats were stratified by BW within BR and randomly assigned to 4 HA. Kids were born between March 15 and April 7 to purebred does, and were represented by at least 3 purebred sires within each BR. They were fed a grain/hay (80:20) diet once per day. At designated HA, randomly pre-assigned goats (n = 6) from each BR were transported to the Meat Science Lab at Mississippi State University, Starkville, MS, and were harvested. There were no interactions (P > 0.10) between BR and HA. Boer tended (P = 0.08) to have greater initial BW, final BW (P = 0.05), and G/F ratio (P = 0.05). Although the 80:20 grain/hay diet was reinforced by adjusting DMI, both BR had similar total DMI, Boer kept that ratio, while Kiko consumed more (P = 0.001) hay (70:30, grain/hay) and had more (P = 0.001) DMI when expressed as g/kg BW. Boer tended to have greater transportation shrink (P = 0.07), HCW (P = 0.08), and cold carcass weights (CCW; P = 0.08), with greater (P = 0.001) carcass fat. No differences (P > 0.10) were observed in carcass shrink, dressing percentage, 12th rib fat thickness, and LM area between the 2 BR. When expressed as percentage empty BW, carcass bone was similar (P = 0.25), whereas muscle percentage (P = 0.02) was greater for Kiko and fat percentage was greater (P = 0.001) for Boer. Fat as a percentage of CCW remained relatively similar (P > 0.10) for both BR for the 2nd and 3rd HA. Differences were more evident (P = 0.01) at the 4th HA. Boer reached targeted harvest weight (29 kg) at the 3rd HA, while fat deposition continued (P = 0.01) during the 4th HA. Breed had no effect (P > 0.10) on meat color (L*, a*, b*) but HA affected (P= 0.001) all color values. Boer had similar 3-hydroxyl-3-methylgluta-ryl-CoA synthase mRNA abundance, but was greater (P < 0.03) in acetyl CoA carboxylase compared with Kiko. There was no difference (P = 0.52) in total serum fatty acids (FA, mg/mL) between the 2 BR. As animals aged, their total serum FA increased (P < 0.05) and changed to an undesirable profile. Kiko had a greater (P = 0.02) percentage of muscle and less (P = 0.001) fat in the carcass. We concluded that different BR might need different harvest endpoints and feed input according to consumer acceptability. [ABSTRACT FROM AUTHOR]

As genetic markers, SNP are well suited for the development of genetic tests for production traits in livestock. They are stable through many generations and can provide direct assessment of indi- vidual animal's genetic merit if they are in linkage disequilibrium and phase with functional genetic variation. Bovine chromosome 5 has been shown to harbor genetic variation affecting production traits in multiple cattle populations; thus, this chromosome was targeted for SNP-based marker development and subsequent association analysis with carcass and growth phenotypes. Discovery of SNP was performed in a panel of 16 sires representing two sires from each of seven beef breeds and two Holstein sires by PCR amplification and sequencing using primers designed from genomic sequence obtained by low-coverage sequencing of bacterial artificial chromosome (BAC) clones. From 550 SNP, 296(54%) were tentatively identified as having a minor allele frequency >10%. Forty-five SNP derived from 15 BAC were chosen based on minor allele frequency and were genotyped in 564 steers and their sires. Production and carcass data were collected on the steers as a part of the Germplasm Evaluation (GPE), Cycle VII Project at the U.S. Meat Animal Research Center (Clay Center, NE), which involves of the evaluation of sires from seven of the most popular U.S. breeds. Haplotypes based on seven SNP derived from a BAC containing the bovine genes HEM1 and PDE1B were associated with traits related to carcass fat. Steers homozygous for the major haplotype had 0.15 ± 0.04 cm less subcutaneous fat, 0.57 ± 0.18 kg less rib fat, 0.18 ± 0.07 lower yield grade, 1.11 ± 0.35% less predicted fat yield, and 0.79 ± 0.3% greater predicted retail product yield than heterozygotes. The frequency of the major haplotype was 0.70 in the steers, and it ranged from 0.44 (Limou-sin) to 0.98 (Simmental and Gelbvieh) in a panel consisting of an average of 20 purebred sires from each of the seven breeds. A second set of haplotypes based on four SNP derived from a BAC containing the genes NOL1 and CHD4 was associated with Warner Bratzler shear force. Steers homozygous for the major haplotype had 0.27 ± 0.11 kg greater shear force than those heterozygous for the major haplotype and one of two minor haplotypes. The frequency of the major haplotype was 0.59 in the steers and ranged from 0.27 (Hereford) to approximately 0.95 (Angus and Red Angus) in the panel of purebred sires. These results demonstrate the feasibility of targeting QTL regions for SNP-based marker development and that a low level of coverage can identify markers associated with phenotypic traits. [ABSTRACT FROM AUTHOR]

Deterministic simulation was used to evaluate 10 breeding schemes for genetic gain and profitability and in the context of maximizing returns from investment in Japanese Black cattle breeding. A breeding objective that integrated the cow-calf and feed-lot segments was considered. Ten breeding schemes that differed in the records available for use as selection criteria were defined. The schemes ranged from one that used carcass traits currently available to Japanese Black cattle breeders (Scheme 1) to one that also included linear measurements and male and female reproduction traits (Scheme 10). The latter scheme represented the highest level of performance recording. In all breeding schemes, sires were chosen from the pro- portion selected during the first selection stage (performance testing), modeling a two-stage selection process. The effect on genetic gain and profitability of varying test capacity and number of progeny per sire and of ultrasound scanning of live animals was examined for all breeding schemes. Breeding schemes that selected young bulls during performance testing based on additional individual traits and information on carcass traits from their relatives generated additional genetic gain and profitability. Increasing test capacity resulted in an increase in genetic gain in all schemes. Profitability was optimal in Scheme 2 (a scheme similar to Scheme 1, but selection of young bulls also was based on information on carcass traits from their relatives) to 10 when 900 to 1,000 places were available for performance testing. Similarly, as the number of progeny used in the selection of sires increased, genetic gain first increased sharply and then gradually in all schemes. Profit was optimal across all breeding schemes when sires were selected based on information from 150 to 200 progeny. Additional genetic gain and profitability were generated in each breeding scheme with ultrasound scanning of live animals for carcass traits. Ultrasound scanning of live animals was more important than the addition of any other traits in the selection criteria. These results may be used to provide guidance to Japanese Black cattle breeders. [ABSTRACT FROM AUTHOR]

A directed search for QTL affecting carcass traits was carried out in the region of growth differentiation factor 8 (GDF8, also known as myostatin) on ovine chromosome 2 in seven Texel-sired half-sib families totaling 927 progeny. Weights were recorded at birth, weaning, ultrasound scanning, and slaughter. Ultrasonic measures of LM cross-sectional dimensions and s.c. fat above the LM were made, with the same measurements made on the LM after slaughter. Following slaughter, linear measurements of carcass length and width were made on all carcasses, and legs and loins from 540 lambs were dissected. Genotyping was carried out using eight microsatellite markers from FCB 128 to RM356 on OAR 2 and analyzed using Haley- Knott regression. There was no evidence for QTL for growth rates or linear carcass traits. There was some evidence for QTL affecting LM dimensions segregating in some sire families, although it was not consistent between ultrasound and carcass measures of the same traits. There was strong and consistent evidence for a QTL affecting muscle and fat traits in the leg that mapped between markers BM81124 and BULGE20 for the four sires that were heterozygous in this region, but not for the three sires that were homozygous. The size of the effect varied across the four sires, ranging from 0.5 to 0.9 of an adjusted SD for weight-adjusted leg muscle traits, and ranging from 0.6 to 1.2 of an adjusted SD for weight-adjusted leg fat traits. The clearest effect shown was for multivariate analysis combining all leg muscle and fat traits analyzed across sires, where the -log10 probability was 14. Animals carrying the favorable haplotype had 3.3% more muscle and 9.9% less fat in the leg relative to animals carrying other haplotypes. There was evidence for a second peak in the region of marker TEXAN2 for one sire group. It seems that a QTL affecting muscle and fat traits exists within the New Zealand Texel population, and it maps to the region of GDF8 on OAR2. [ABSTRACT FROM AUTHOR]

Studies with different populations arc required to properly characterize the robustness of associations of polymorphisms in candidate genes with economically important traits across beef cattle populations before this sort of genetic information can be used efficiently in breeding and management decisions. The objective of this study was to evaluate the association of previously reported SNP in the bovine leptin gene with carcass and meat quality traits from a large sample of crossbred beef cattle. Five SNP (UASMSI UASMS2, UASMS3, E2JW, and E2FB) were genotyped on 1,111 crossbred bulls, heifers, and steers. The measured traits included fat, lean, and bone yield (%) by partial rib dissection, grade fat, LM area, HCW, quality grade, LM i.m. fat, and tenderness evaluation of LM and semitendinosus muscle. Only four SNP were analyzed (UASMS1, UASMS2, E2JW, and E2FB), because UASMS1 and UASMS3 were completely linked. A univariate mixed-inheritance animal model was used to evaluate the association of either genotypes or haplotypes with the traits. The two leptin exon 2 SNP were associated with fat and lean yield and grade fat (E2JW, P < 0.01, E2FB, P < 0.05), and they interacted in their effect on LM tenderness (P < 0.01). The leptin promoter SNP were either not associated with any of the traits (UASMS2) or with fat yield only (UASMS1). Three haplotypes (TCAC, CCAT, TTAC) were at high frequency in the population (88%) and had similar effects on all the traits. Compared with the common haplotypes, one haplotype (CCTT) showed a significantly different effect on fat and lean yield and grade fat (P < 0.01), and one haplotype (TTTT) had a different effect on LM tenderness (P < 0.03). Therefore, important associations between SNP within the leptin gene with lean yield, fatness (fat yield and subcutaneous fat), and tenderness were detected. Results confirm some of the previously reported associations, but diverge with respect to others, showing that further efforts are required to validate some prospective associations. [ABSTRACT FROM AUTHOR]

The importance of genotype × environment (region or management system) interactions for carcass traits in Japanese Black cattle was investigated using both univariate and multivariate animal models. The univariate approach was used mainly to test the significance of interaction effects. The multivariate approach was used to estimate genetic correlations, which indicated the magnitude of genotype × environment (GE) interactions. The more a genetic correlation deviates from 1, the larger the interaction. From the univariate approach, the addition of genotype × environment (region or management system) interaction (co)variance components resulted in an improved fit of the model for all traits in both cases (P < 0.001). However, estimates of genetic correlation between regions obtained from the multivariate approach for hot carcass weight, LM area, rib thickness, s.c. fat thickness, and marbling score were 0.97, 0.95, 0.93, 0.97, and 0.93, respectively. The corresponding estimates between management systems were 0.84, 0.92, 0.84, 0.90, and 0.97, respectively. These results indicate that GE interaction effects on carcass traits of Japanese Black cattle may be biologically unimportant. Therefore, breeding values obtained using the multivariate method would rank sires similarly in all environments. Consequently, carcass traits measured in these two different regions or management systems can be treated as the same traits. [ABSTRACT FROM AUTHOR]

An experiment was conducted to determine the effect of dietary Cr propionate (CrProp) on growth, carcass traits, and pork quality of crossbred finishing gilts. Dietary treatments were 0 or 200 ppb Cr (as CrProp; as-fed basis), and each treatment was replicated four times with five guts per replicate pen. Gilts were fed diets containing 0.82% lysine from 73 to 80 kg BW and 0.64% lysine from 80 to 115 kg BW. At the end of the trial, carcass and pork quality data were collected from four gilts per replicate. Average daily gain, ADFI, and G:F were not affected (P = 0.76 to 0.96) by CrProp. Before delivery at the abattoir, shrink loss was determined after an 18-h fast (fasting shrink) and after hauling (shipping shrink) pigs for 2.66 h (209.2 km). Fasting, shipping, and overall shrink were not affected (P = 0.14 to 0.39) by CrProp. Carcass length was increased (P = 0.03) in pigs fed CrProp. Loin muscle area, 10th-rib backfat thickness, average backfat thickness, dressing percent, muscle score, fat-free lean, and percent lean were not affected (P = 0.18 to 0.95) by CrProp. Twenty-four-hour loin pH was increased (P = 0.10) in pigs fed CrProp, but 45-mm loin and ham pH and 24-h ham pH were not affected (P = 0.39 to 0.83) by CrProp. Subjective (color, marbling, firmness, and wetness) and objective (Commission Internationale de l'Éclairage L&loast;, a&loast;, b&loast;) assessments of the loin muscle (at the 10th-rib interface) were not affected (P = 0.62 to 0.99) by CrProp. Forty-eight-hour drip (P = 0.10) and 21-d purge loss (P = 0.01) were decreased in pigs fed CrProp, but cook and total loss (drip + cook loss) and shear force were not affected (P = 0.35 to 0.53) by CrProp. Plasma cortisol, glucose, and lactate concentrations were not affected (P = 0.28 to 0.97) by CrProp after transportation or during exsanguination. These data indicate that CrProp may improve some aspects of pork quality (loin pH, drip and purge loss) but not growth performance or carcass traits. [ABSTRACT FROM AUTHOR]

Carcass measurements from 1,664 steers from the Germ Plasm Utilization project at U.S. Meat Animal Research Center were used to estimate heritabilities (h2) of, and genetic correlations (rg) among, 14 carcass traits adjusted to different endpoints (age, carcass weight, and fat thickness): HCW (kg), dressing percent (DP), adjusted fat thickness (AFT, cm), LM area (LMA, cm2), KPH (%), marbling score (MS), yield grade (YG), predicted percentage of retail product (PRP), retail product weight (RPW, kg), fat weight (FW, kg), bone weight (BNW, kg), actual percentage retail product (RPP), fat percent (FP), and bone percent. Fixed effects in the model included breed group, feed energy level, dam age, birth year, significant (P < 0.05) interactions, covariate for days on feed, and the appropriate covariate for endpoint nested (except age) within breed group. Random effects in the model were additive genetic effect of animal and total maternal effect of dam. Parameters were estimated by REML. For some traits, estimates of h2 and phenotypic variance changed with different endpoints. Estimates of h2 for HCW, DP, RPW, and BNW at constant age, weight, or fat thickness were 0.27, -, and 0.41; 0.19, 0.26, and 0.18; 0.42, 0.32, and 0.50; and 0.43, 0.32, and 0.48, respectively. Magnitude and/or sign of rg also changed across endpoints for 54 of the 91 trait pairs. Estimates for HCW-LMA, AFT-RPW, LMA-YG, LMA-PRP, LMA-FW, LMA-RPP, and LMA-FP at constant age, weight, or fat thickness were 0.32, -, and 0.51; -0.26, -0.77, and -; -0.71, -0.89, and -0.66; 0.68, 0.85, and 0.63; -0.16, -0.51, and 0.22; 0.47,0.57, and 0.27; and -0.44, -0.43, and -0.18, respectively. Fat thickness was highly correlated with YG (0.86 and 0.85 for common age and weight) and PRP (-0.85 and -0.82 for common age and weight), indicating that selection for decreased fat thickness would improve YG and PRP. Carcass quality, however, would be affected negatively because of moderate rg (0.34 and 0.35 for common age and weight) between MS and AFT. Estimates of h2 and phenotypic variance indicate that enough genetic variation exists to change measures of carcass merit by direct selection. For some carcass traits, however, magnitude of change would depend on effect of endpoint on h2 and phenotypic variance. Correlated responses to selection would differ depending on endpoint. [ABSTRACT FROM AUTHOR]

We characterized the nearly complete coding sequence of the pig 2,4-dienoyl CoA reductase 1 (DECR1) gene, which encodes an enzyme involved in the β-oxidation of polyunsaturated fatty enoyl-CoA esters and maps on a linoleic QTL located on Chromosome 4. Sequencing of a 937-bp fragment encompassing exons 2 and 10 revealed the existence of two missense SNP at exon 2 (C181 → G181) and exon 5 (C458 → G458). These two SNP are associated with Val (C) → Leu (G) and Ser (C) → Thr (G) conservative AA replacements at positions 61 and 153 of the DECR1 protein, respectively. Moreover, DECR1 genotyping in a representative sample of 184 pigs from the Large White, Piétrain, Iberian, Duroc, and Landrace breeds demonstrated the existence of disequilibrium linkage between these two SNP (Haplotype 1:C181C458; Haplotype 2: G181G458). An association analysis between DECR1 genotype and growth, carcass, and meat quality traits in a highly selected Landrace population (n = 470) revealed differences among genotypes for isocitrate dehydrogenase activity (highest posterior density [HPD] of 90%), longissimus thoracis pH (HPD of 95%), lightness (HPD of 90 to 95%), and redness (HPD of 95%). Because these associations were not consistently found in the three available genotype comparisons, we believe that exon 2 and 5 polymorphisms at the DECR1 gene might be in linkage disequilibrium with the true causal mutation influencing isocitrate dehydrogenase activity and muscle color and pH. [ABSTRACT FROM AUTHOR]

The effects of propylene glycol (PEG) on performance, ruminal fermentation, blood glucose and insulin, carcass traits, and abundance of IGF-1 mRNA in LM and leptin mRNA in adipose tissue were examined in 20 Korean native steers, with 10 each in control and PEG-fed groups, respectively. Propylene glycol mixed with concentrate diet was provided daily at a rate of 2.5 mL/kg BW0.75. Experimental animals were fed a concentrate diet to 1.8% of BW twice daily plus rice straw ad libitum during the 4-mo period before marketing. Daily DMI and ADG did not differ between control and PEG-fed steers. Steers receiving PEG displayed an increase (P = 0.044) in propionate concentration, whereas acetate concentration decreased (P = 0.032). Although blood glucose was not affected, serum insulin was increased (P = 0.047) by PEG feeding. Propylene glycol did not affect carcass weight, 13th-rib fat depth, marbling score, or lipid content of LM. The backfat of PEG-fed steers did not differ in leptin mRNA from control steers, whereas increased leptin mRNA was found in i.m. fat with PEG feeding. There was no treatment effect on the level of IGF- 1 mRNA in the LM of the tested steers. These results indicate that the amount of PEG fed to steers was not sufficient to im- prove marbling score through enhanced ruminal propionate and insulin. The role of increased i.m. leptin mRNA level in PEG-fed steers remains to be further elucidated. [ABSTRACT FROM AUTHOR]

Objective of this study was to assess the association of SNP in the diacylglycerol O-acyltransferase 1 (DGAT1), thyroglobulin (TG), and micromolar calcium-activated neutral protease (CAPN1) genes with carcass composition and meat quality traits in Bos indicus cattle. A population of Brahman calves (n = 479) was developed in central Florida from 1996 to 2000. Traits analyzed were ADG, hip height, slaughter weight, fat thickness, HCW, marbling score, LM area, estimated KPH fat, yield grade, retail yield, sensory panel tenderness score, carcass hump height, and cooked meat tenderness measured as Warner-Bratzler shear force at 7, 14, and 21 d postmortem. Single nucleotide polymorphisms previously reported in the TG and DGAT1 genes were used as markers on chromosome 14. Two previously reported and two new SNP in the CAPN1 gene were used as markers on chromosome 29. One SNP in CAPN1 was uninformative, and another one was associated with tenderness score (P < 0.05), suggesting the presence of variation affecting meat tenderness. All three informative SNP at the CAPN1 gene were associated with hump height (P < 0.02). The TG marker was associated with fat thickness and LMA (P < 0.05), but not with marbling score. No significant associations of the SNP in the DGAT1 gene were observed for any trait. Allele frequencies of the SNP in TG and CAPN1 were different in this Brahman population than in reported allele frequencies in Bos taurus populations. The results suggest that the use of molecular marker information developed in Bos taurus populations to Bos indicus populations may require development of appropriate additional markers. [ABSTRACT FROM AUTHOR]

Presents abstracts of studies about breeding and genetics of beef cattle. "Teat Scores in First-Parity Gelbvieh Cows: Relationship With Suspensory Score and Calf Growth Traits," by R.L. Sapp, R. Rekaya and J.K. Bertrand; "Calving Day and Age at First Calving in Angus Heifers," by J. Minick and D. Wilson; "Genetic prediction for Estimating Mature Cow Maintenance Energy Requirements," by S.E. Speidel, D.J. Garrick and R.M. Enns.

Presents abstracts of several studies on nonruminant pig nutrition. "Advantages of Formulating Diets Based on Net Energy on Pig Performance, Carcass Characteristics and Production Economics," by M. Rademacher and L. Hagemann; "Energy, Protein, and Amino Acid Digestibility in Different Sources of Rice Bran for Growing Pigs," by C. Kaufmann and colleagues; "Comparison of a Diet Containing Food Waste With a Corn/Soybean Diet Fed to Swine," by J. Jones, M. L. Westendorf and J. E. Wohlt.

Presents abstracts of several studies on animal breeding and genetics. "The Impact of Herd Opportunity and Milk Recording Periods in Estimating Lifetime Net Income," by E. Yook, R. E. Pearson and B. G. Cassell; "Joint Genetic Evaluation of Male and Female Fertility Using Longitudinal Binary Responses," by R. Rekaya and T. Averil; "Contribution of Inbreeding and Recessive Defects to Early Embryo Loss," by P. M. VanRaden and R. H. Miller; "Effects of Climate and Photoperiod on Feed Intake of Beef Bulls During Feedlot Performance Tests," by G. T. Tabler Jr., A. H. Brown Jr., Z. B. Johnson, E. E. Gbur Jr., I. L. Berry, D. W. Kellogg and K. C. Thompson.

We used a half-sib family of purebred Japanese Black (Wagyu) cattle to locate economically important quantitative trait loci. The family was composed of 348 fattened steers, 236 of which were genotyped for 342 microsatellite markers spanning 2,664 cM of 29 bovine autosomes. The genome scan revealed evidence of 15 significant QTL (<5% chromosome-wise level) affecting growth and carcass traits. Of the 15 QTL, six QTL were significant at the 5% experiment-wise level and were located in bovine chromosomes (BTA) 4, 5, and 14. We analyzed these three chromosomes in more detail in the 348 steers, with an average marker interval of 1.2 cM. The second scan revealed that the same haplotype of the BTA 4 region (52 to 67 cM) positively affected LM area and marbling. We confirmed the QTL for carcass yield estimate on BTA 5 in the region of 45 to 54 cM. Five growth-related QTL located on BTA 14, including slaughter and carcass weights, were positively affected by the same region of the haplotype of BTA 14 (29-51 cM). These data should provide a useful reference for further marker-assisted selection in the family and positional cloning research. The research indicates that progeny design with moderate genotyping efforts is a powerful method for detecting QTL in a purebred half-sib family. [ABSTRACT FROM AUTHOR]

Two trials were conducted to determine the replacement nutritive value of dried skim milk for growing-finishing pigs. In a three-phase feeding trial, 180 growing composite harrows (40.8 ± 2.9 kg BW) were allotted to three dietary treatments. Each phase lasted 28 d. Treatment 1 comprised a basal comsoybean meal diet supplemented with crystalline AA to contain true ileal digestible concentrations (as-fed basis) of 0.83, 0.66, and 0.52% Lys; 0.53, 0.45, and 0.40% Thr; and 0.51, 0.45, and 0.42% sulfur amino acids (SAA; Met + Cys) in Phases 1, 2, and 3, respectively. Treatments 2 and 3 were the basal diets with 5 and 10% (as-fed basis) dried skim milk added. The three diets at each phase were formulated to have the same quantities of DE, true ileal digestible Lys, Thr, Trp, SAA, Ca, and available P. Pigs were housed 10 per pen (six pens/treatment), allowed ad libitum access to feed, and slaughtered at 121.6 ± 9.3 kg BW. No differences were detected between pigs fed the basal diet and the dried skim milk diets or between pigs fed the 5 and 10% dried skim milk diets, respectively, in 84-d ADG (P = 0.84 or P = 0.71), ADFI (P = 0.54 or P = 0.91), and G:F (P = 0.80 or P = 0.97), in hot carcass weight (P = 0.66 or P = 0.74), 45-min postmortem LM pH (P = 0.90 or P = 0.53), 10th rib backfat thickness (P = 0.24 or P = 0.77), LM area (P = 0.13 or P = 0.63), weights of belly (P = 0.43 or P = 0.70), trimmed wholesale cuts (P = 0.18 to 0.85 or P = 0.06 to 0.53), and ham components (P = 0.25 to 0.98 or P = 0.32 to 0.63). In the N balance trial, four littermate pairs of finishing gilts (82.9 ± 2.0 kg BW) were assigned within pair to the basal or the 10% dried skim milk (as fed basis) finishing diet. Daily feed allowance was 2.6x maintenance DE requirement and was given in two equal meals. Total fecal collection from eight meals and a 96-h urine collection began on d 14 when gilts weighed 92.1 ± 2.2 kg BW. No differences were found between dietary treatments in gilt's daily N intake (P = 0.33) and the daily output of urinary urea (P = 0.88), urinary N (P = 0.97), fecal N (P = 0.69), and total manure (P = 0.62), as well as apparent total-tract N digestibility (P = 0.84) and N retention (P = 0.84). It is concluded that growing-finishing pigs fed diets containing 10% dried skim milk would have growth performance, carcass traits, and N digestibility and use similar to those fed typical corn-soybean meal diets. [ABSTRACT FROM AUTHOR]

The Pit-1 gene was studied as a candidate for genetic markers of growth and carcass traits. Angus beef cattle that were divergently selected for high- or low-blood serum IGF-I concentration were used m this study. The single-strand conformation polymorphism method was used to identify polymorphism in the Pit-1 gene including regions from intron 2 to exon 6. Two polymorphisms, Pit1I3H (Hinfi) and Pit1I3NL (NlaIII), were detected in intron 3 of the Pit-1 gene. One polymorphism, Pit1I4N (BstNI), was found in intron 4, and a single nucleotide polymorphism, Pit1I5, was found in intron 5. The previously reported polymorphism in exon 6, Pit1E6H (HinfI), was also studied in 416 Angus beef cattle. Associations of the polymorphisms with growth traits, carcass traits, and IGF-I concentration were analyzed using a general linear model procedure. No significant associations were observed between these polymorphisms and growth and carcass traits. [ABSTRACT FROM AUTHOR]

The experiment objective was to evaluate the impact of assisted reproductive technologies on post weaning calf performance. Calves born following various reproductive treatments (synchronized natural service and synchronized AI) in 10 herds over 2 years were fed to reach a target backfat (BF) of 1.27 cm, sent to harvest, and carcass data collected. Calves were classified into calving groups as natural service born early (NS-Early, n = 189), natural service born late (NS-Late, n = 203), or AI sired born early (AI-Early, n = 116). Data were analyzed using the MIXED procedure in SAS with calving group, year and calf gender in the model. Weaning weights were similar between AI-Early and NS-Early; however, earlier born calves (AI-Early and NS-Early) were heavier (P < 0.0001) than NS-Late. AI-Early calves had heavier finished bodyweight (622.2 kg: P = 0.0024) compared to NS-Early (601.4 kg) and heavier HCW compared to both NS-Early and NS-Late (P < 0.01). NS-Early calves reached 1.27 cm BF in fewer days than AI-Early (261 d and 275 d, respectively; P < 0.01) with NS-late requiring the most days on feed to reach the same endpoint (296 d, P < 0.01). No differences in Quality Grade, Yield Grade, REA, marbling, or BF were detected between AI-Early, NS-Early, and NS-Late, or between early- and late-born calves (P > 0.38). Late-born calves required 29 more days on feed (P < 0.001) to reach 1.27 cm BF resulting in greater final bodyweight compared to early-born calves (625.5 kg and 612.8 kg, respectively; P = 0.04); however, hot carcass weights were similar between early- and late-born calves. Reproductive technologies that increase the number of calves born early in the calving season increased weaning weight and post weaning growth performance, but compared to high quality natural service sires, AI did not improve carcass characteristics. [ABSTRACT FROM AUTHOR]

The article presents a study aimed at analyzing the compensatory growth and carcass quality of restricted and refed beef steer. Topics discussed include libitum consumption (CA) by beef, compensatory gain in beefs, influence of feeding on carcass quality, thickness of backfat in beef steers and libtium consumption.

The article reports on study which examines repeatability as well as accuracy of ultrasound measurements of a particular rib backfat (FAT) and longissimus muscle area (LMA) in case of beef cattle. The study concluded that ultrasound is right method of measuring carcass traits in live steers if suitable persons and equipment are used.

The article offers information on a study which aims at comparing Finnish Landrace and Romanov as Prolific Breeds in a Terminal-Sire Crossbreeding System. It presents information regarding higher rate of embryonic survival for purebred Romanovs than for purebred Finnish Landrace. It states that post weaning diets of terminal lambs were the same as those of the F1 lambs.