Live Performance Traits Research Articles

Effects of the F94L myostatin gene mutation in beef × dairy crossed cattle on muscle fiber type, live performance, carcass characteristics, and boxed beef and retail cut yields.

Producer live performance data and carcasses from steers (n = 116) resulting from the mating of four Limousin/Angus sires heterozygous for the F94L myostatin mutation to Jersey/Holstein dams were utilized to evaluate the effects of one copy of the F94L allele on live performance, carcass traits and USDA grades, and boxed beef and retail yields. Slaughter data were collected at time of harvest and carcass data were collected 48 hours postmortem. One side from each of the 58 carcasses was fabricated into boxed beef and retail cuts by experienced lab personnel 5-8 d postmortem. One copy of the F94L allele did not affect gestation length, birth weight, percentage of unassisted births, feedlot average daily gain, live weight at harvest, hot carcass weight, or dressing percentage (P > 0.05). Muscle fiber analysis indicated that the increase in muscularity by the F94L allele in the semitendinosus and longissimus was likely due to hyperplasia as there was a 19% increase in the quantity of myosin heavy chain type IIA and IIX fibers in the semitendinosus (P < 0.05) with no effect on muscle fiber size (P > 0.05). Carcasses from steers with one F94L allele had larger ribeye areas (99.2 vs. 92.3 sq.cm.), greater ribeye width:length ratios (0.498 vs. 0.479), lower USDA yield grades (2.21 vs. 2.66), and lower marbling scores (438 vs. 480) (P < 0.05). Additionally, for boxed beef yields, one F94L allele, vs. zero F94L alleles, increased (P < 0.05) 85/15 trimmings (+0.59%), top round (+0.28%), strip loin (+0.12%), eye round (+0.11%), tenderloin (+0.07%), boneless foreshank (+0.07%), cap/wedge (+0.06%), and tri-tip (+0.04%). Overall, carcasses from steers with one F94L allele had a greater boxed beef yield (+1.06%), boxed beef plus 85/15 trimmings yield (+1.65%), and total retail cuts plus ground beef 85/15 yield (+1.78%) than carcasses from steers with zero F94L alleles (P < 0.05). One copy of the F94L allele utilized in beef-on-dairy breeding system had no significant impact on live performance traits but resulted in lower marbling scores and increased muscularity as evidenced through larger, more beef-shaped ribeyes, lower USDA yield grades, and greater carcass cutout yields (both boxed beef and retail yields).

Iron requirements of broiler chickens as affected by supplemental phytase.

Iron is routinely supplemented in broiler feeds intending to prevent dietary deficiencies. The present research was conducted with the objective of assessing Fe requirements of broilers when fed supplemental phytase. A total of 1,280 1-d-old male Cobb × Cobb 500 were distributed in a 2 × 5 factorial arrangement (phytase-supplemented feeds × 5 graded increases of supplemental Fe) in 80 battery cages, eight replications of eight chicks each. The trial was replicated once. Chicks were fed a Fe-deficient diet without phytase (Fe analyzed at 31.30 ± 3.79 mg/kg) from placement to 7 d and then randomly distributed into battery cages with corresponding dieting treatments with or without phytase and graded increases of supplemental Fe. Feeds were formulated with corn and soybean meal (SBM), laboratory-grade calcium carbonate, and phosphoric acid; therefore, the vast majority of dietary Fe originated from corn and SBM (analyzed diet had 53.3 ± 1.41 mg/kg Fe). Phytase was added in excess to the producer recommendation of 1,000 FYT (4,452 ± 487 FYT/kg analyzed) such that phytate degradation was expected to be maximized. Supplemental Fe was from laboratory-grade ferrous sulfate heptahydrate (FeSO47H2O) which was increasingly added to the feeds (analyzed Fe in the supplemented feeds were: 53.3 ± 1.41, 65.5 ± 0.59, 77.2 ± 1.97, 87.6 ± 1.72, 97.7 ± 1.33 mg/kg). There were no interactions between phytase and dietary Fe for any response throughout the study (P > 0.05). Supplementing phytase had no effects on Fe intake or Fe excretion, as well as on hematocrit (Ht), hemoglobin (Hb), ferritin, Fe contents in the liver or thigh muscle color (P > 0.05). However, phytase-supplemented feeds produced better live performance as well as higher ileal digestible energy and Fe digestibility (P < 0.05). No effects were found for dietary Fe in live performance at day 28 (P > 0.05). On the other hand, increasing dietary Fe led to linear increases in Fe retention and excretion, Fe contents in livers, as well as Ht and Hb at 14 d (P < 0.05). Quadratic responses (P < 0.05) were observed for Hb at 21 d, serum ferritin on days 14, 21, and 28 (maximum responses were 83.3, 104.0, 91.9, and 88.3 mg/kg Fe, respectively). In conclusion, supplementing Fe adding to a total of 97.7 mg/kg dietary Fe did not affect live performance traits. However, the average of Fe-related blood parameters was maximized at 91.9 mg/kg dietary Fe. Supplementing phytase provided a significant increase in Fe digestibility.

STRAIN DIFFERENCES IN THE GENETIC PARAMETER ESTIMATES FOR GROWTH TRAITS IN MEAT-TYPE CHICKEN

Data on live performance traits obtained from experiments involving two strains of meat-type chicken were analysed and used to estimate heritabilities of the traits and the -inter-character correlations. There were strain differences (P&lt;0.05) for body weight of birds to 56 days of age, average daily gain, and daily feed intake per bird. Strain differences were not significant (P&gt;0.05) for feed conversion ratio. Genetic correlations obtained between pairs of characters were generally high (P&lt;0.01). Coefficients of phenotypic correlation were slightly lower relative to those of the genetic correlation. Environmental correlation coefficients were moderate to high (0.36 to 0.99) and also significant (P&lt;0.01) within strains. Correlation of feed conversion rate with other characters wert negative for the two strains, Heritability estimates for the growth traits wa very high, and no appreciable differences were observed between the strains.

Effect of an in-vivo and/or in-meat application of a liquorice (Glycyrrhiza glabra L.) extract on fattening rabbits live performance, carcass traits and meat quality

The present study tested the effect of a liquorice root extract (L) administration in the diet of growing rabbits and/or in their minced meat. A total of fifty-six rabbit does and their kits (3 weeks of age) were divided into 4 groups receiving a commercial diet (C) or the C diet supplemented with increasing levels of L: 2 g/kg (L2), 4 g/kg (L4), 6 g/kg (L6). At weaning (5 weeks of age), sixty rabbits/group were randomly selected, caged by 3, and fed ad libitum with the experimental diets until slaughter (12 weeks of age). At 6 weeks of age, 6 rabbits/diet were selected for gastrointestinal tract pH and caecal microbial count analyses. Live performance and health status were recorded weekly and daily, respectively. Carcass traits were measured after slaughter and hind leg (HL) and Longissimus lumborum (LL) meat were dissected for pHu and L*a*b* colour measurements. Minced meat from HL belonging to C and L6 dietary treatments was each split in two parts to incorporate liquorice extract at 0.25% (w/w), obtaining four groups of meat burgers: CC; CL; L6C and L6L. The pH, L*a*b* colour and microbial count (TVC, Coliforms, and Pseudomonas) were measured at days 0, 3 and 6 of refrigerated storage. A sensory analysis was conducted on LL meat of C and L6 dietary treatments, and tested attributes were odour, taste, flavour, texture and off-flavours. Liquorice dietary inclusion did not show a clear effect on live performance, resulting comparable among groups, with exception of the lowest growth rate for L2 rabbits (P < 0.001) that impaired their slaughter yield. Total aerobic bacteria of the caecal content increased with L inclusion level (P < 0.05). Rabbits of the L6 group exhibited the highest carcass weight with higher proportion of the mid part of the carcass (P < 0.01), but to the detriment of the hind part (P < 0.05), compared to the C group rabbits. Liquorice dietary inclusion level significantly increased dissectible fat proportion on the chilled carcass, due to the increase of perirenal fat depot (P < 0.05). Sensory analysis on the loin meat did not reveal differences in the considered attributes due to the dietary treatment. The L6C and L6L burgers exhibited the lowest microbial growth (particularly Pseudomonas) during refrigerated storage. In conclusion, live performance traits of rabbits seem not to benefit from the dietary supplementation of liquorice extract. However, the dietary inclusion was more effective than the incorporation into meat as antimicrobial on meat burgers. The combination of dietary and in-meat supplementation of liquorice extract exhibited the most effective antimicrobial effect.

Analysis of Genetic Parameters of Carcass Traits and Daily Gain of Native Breed Pigs Raised in Poland

Abstract The aim of the study was to determine genetic parameters of live performance traits in pigs of three native breeds maintained in Poland. As part of the conservation programmes, the Puławska (Puł), Złotnicka White (ZW) and Złotnicka Spotted (ZS) breeds are monitored for productivity based on performance test results of these breeds. The study included 6042 gilts and 2406 boars of the Puławska breed, 866 Złotnicka White gilts, and 903 Złotnicka Spotted gilts. The genetic parameters were estimated separately for each breed, and also separately for sexes in the case of the Puławska breed. The components (co)variance and genetic parameters were estimated using the REML method for the animal model taking into account different combination of fixed and random effects. Convergence of the iterative process was achieved by the selection of AIREML algorithm. The coefficients of genetic and phenotypic correlations between measurements of slaughter traits and daily gain were low for all breed groups. In turn, the relationships between backfat thickness measurements and carcass meat percentage were estimated as high. Only the correlations of slaughter traits with loin eye height were not uniform for the analysed breed groups. The coefficients of heritability (h2) were high and intermediate for all breeds and sexes. The highest heritability coefficients were obtained for daily gain (0.58 in ZW to 0.80 in Puł gilts), followed by backfat thickness (0.37 in Puł gilts to 0.64 in ZW) and carcass meat percentage (0.40 in ZS to 0.56 in ZW). The lowest coefficients were obtained for loin eye height (0.24 in Puł boars to 0.40 in ZW). The estimated genetic parameters could be used to verify selection indices of the breeds included in the genetic resources conservation programmes.

Genetic parameters of feeding behavior traits and their relationship with live performance traits in modern broiler lines

Current selection goals in broiler breeding focus on the improvement of live performance traits, such as feed intake, BW, and feed conversion ratio (FCR). The use of electronic feeders allows measurement of feed intake of individuals housed in groups as well as the identification of different feeding behaviors. Feed intake can thus be split into underlying feeding behavior traits, allowing the estimation of genetic correlations and assessment of the genetic consequences of selecting for performance traits on feeding behavior traits. To investigate the genetic relationships between performance traits and feeding behavior, data of visits to feeders by birds from 4 lines of broilers that differed in selection focus on growth and FCR were analyzed. Visits were recorded electronically and grouped into meals using an existing model for estimating meal criteria. Mean individual feeding behavior traits were then calculated across the entire test period (2 to 5 wk of age). Records were available for between 14,000 and 18,000 birds/line. Analyzed feeding behavior traits were meals per day, meal size, visits per meal, meal duration, nonfeeding time in meal, time feeding per day, proportion of meal spent feeding, feeding rate, and ADFI. Analyzed performance traits were 35-d BW, total feed intake over the entire test period, and FCR. All feeding behavior traits showed moderate to high heritabilities (0.24 to 0.57) but low genetic correlations with performance traits (-0.20 to 0.18), except for ADFI, which was moderately correlated with total intake on test (0.57) and highly correlated with FCR (0.91). The low genetic correlations indicate that the difference in selection intensity among lines for these performance traits has had limited effect on feeding behavior. Different feeding strategies that would result in favorable breeding values for FCR were identified, adding opportunities for further improvements in feed efficiency within and across environments.

Genetic parameters for growth, muscularity, feed efficiency and carcass traits of young beef bulls

Genetic parameters were estimated for feed efficiency and live performance traits of 678 Blonde d'Aquitaine (BA) and 708 Limousin (LI) bulls born between 1991 and 2007, and for carcass traits of 3755 BA and 5263 LI progeny. Records at weaning were registered on-farm in 277 BA and 298 LI herds having provided purebred males for the French selection scheme of progeny tested bulls destined to artificial insemination. Analyzed traits included weight (WW) and muscle score (WM) recorded at weaning, and weight (LW) and muscle score (LM) recorded on bulls in performance test stations at 15 months. Feed intake (FI), residual feed intake (RFI) and feed conversion ratio (FCR) were also recorded in performance test stations. Carcass traits recorded in progeny test stations were age-adjusted carcass weight (CW), dressing percentage (DP), European commercial score for carcass muscularity (CM) and carcass internal fatness score (CF). Multivariate analyses were performed on different trait combinations using BLUP animal model and REML methodology. Heritability estimates for WW, WM, LW, LM, FI, RFI, FCR, CW, DP, CM and CF were 0.27, 0.31, 0.57, 0.64, 0.30, 0.26, 0.30, 0.53, 0.62, 0.47 and 0.47 for BA, respectively, and 0.35, 0.35, 0.63, 0.51, 0.48, 0.45, 0.23, 0.61, 0.47, 0.54 and 0.38 for LI, respectively. Genetic correlations ( r g) between live performance traits and the corresponding carcass traits were strong in both breeds, ranging from 0.52 to 0.98. Thus, an early selection on live traits recorded at weaning should improve carcass value of young bulls. In both breeds, genetic correlations were null to weak between growth and muscularity at weaning and feed utilization traits (| r g| < 0.30). LW was strongly genetically correlated with FI (| r g| > 0.71) but weakly to moderately negatively with RFI and FCR (| r g| < 0.30). In both breeds, RFI was genetically independent from CF and weakly related to DP. Over the period 1991–2007, realized genetic trends estimated on males entering AI bull test stations were clearly positive on CW. For BA and LI bulls, annual trends were equal to 3.9% and 5.0% of genetic standard deviation ( σ g) per year, respectively. Estimated trends were lower for CM (1.3% and 3.7% σ g per year, respectively), for RFI (− 1.5% and 0.0% σ g per year, respectively) and FCR (− 1.0% and − 2.3% σ g per year, respectively).

Response of fattening rabbits reared under different housing conditions. 1. Live performance and health status

In a 2 × 2 × 2 factorial experiment the effects of housing system (pair caged (cage): 2 rabbits/0.122 m 2 vs open top pen housed (pen): 13 rabbits/0.86 m 2; same stocking density), floor type (wire mesh vs plastic net) and environmental enrichment (with vs without gnawing stick) were studied on live performance, health status and welfare (ear lesions) of growing rabbits ( n = 176). The housing system significantly influenced the body weight at 11 weeks of age (2630 vs 2557 g; in cage or pen, respectively) and the feed conversion (3.12 vs 3.38 g/g; in cage or pen, respectively). Floor type did not affect the traits tested. Gnawing stick consumption affected the body weight at 11 weeks of age (2553 vs 2622 g; without or with gnawing stick, respectively), the percentage of ear lesions (18.5 vs 1.20%; without or with gnawing stick, respectively). Some of the live performance traits of rabbits reared in pens was slightly lower. The presence of gnawing stick, especially in pens, reduced the aggressive behaviour and improved the welfare.

Predicting Semen Attributes of Naked Neck and Normally Feathered Male Chickens from Live Performance Traits

The current research was conducted to estimate the prediction equations of semen characters from live performance traits. The performance traits were body weight (BW) and length of shank (SL), comb (CL) and wattle (WL). For this purpose 102 cocks (26 Fayoumi-Nana, 25 Fayoumi-nana, 27 Dandarawi-Nana and 24 Dandarawi-nana) were used. The Fayoumi strain had significantly wider wattle length, higher abnormal sperms and lower coiled tail sperms compared to Dandarawi one. With respect to naked neck (Na) gene, the results indicated that the Na gene had taller CL, wider WL, higher semen volume and lower PSV and higher abnormal sperms compared to normally feathered genotype. In all genetic groups, the coefficients of sample correlation between the body weight and PSV were highly positive and statistically significant. Also, both PSV and abnormal sperms were significantly correlated with BW, CL and WL. Within Dandarawi strain, the BW, CL and WL are good predictors for semen volume in Nana genotype. However, BW alone is good predicator of semen volume in nana genotype. Moreover, within Fayoumi strain, the BW and WL are good predicators for semen volume in Nana genotype. Also, the CL alone is a good predictor for semen volume in nana genotype. The BW, CL and WL are good predictors for PSV in both Fayoumi-nana (R = 0.75) and Fayoumi-Nana (R = 0.65). According to the findings in this study, it may be concluded that 2 2 the body weight and lengths of shank, comb and wattle are good predictors of semen attributes in chickens. Moreover, the accuracy of prediction equations (R ) increased with the presence of naked neck (Na) gene, 2 in Fayoumi strain, but not in Dandarawi one.

EFFECT OF DIETARY VITAMIN E SUPPLEMENTATION ON MEAT PRODUCTION RELATED TRAITS OF BARKI LAMBS

The purpose of the present study was to evaluate the effects of dietary vitamin E supplementation (DVES) on the meat production traits. Ten Barki lambs, 8 months old, were randomly assigned into two equal groups with similar (P>0.05) initial body weights (29±2.63 kg). The first group (G0) received no supplement, while, the second group (G500) was orally administered 500 IU vitamin E/lamb/day. Both groups were fed concentrate mixture and wheat straw for 120 days before slaughter at 12 months of age. Meat production related traits involved those concerning lambs fatteners (average daily gain and final body weight), retailers (carcass weight, dressing percentage, total non-carcass fat partitioning between depots and meat pH) and consumers (physical and chemical characteristics). Color parameters (redness, yellowness and brightness) were assessed under two main factors; DVES level (0, 500 IU) and storage periods (2, 7, 14 days). DVES had no significant (P>0.05) effect on live performance traits, carcass weight and dressing percentage. Use of DVES enhanced the proportion of total noncarcass fat deposited in the tail and decreased that deposited around the kidneys and in the abdomen. The treatment boosted intramuscular fat percentage assessed chemically. Significant (P<0.05) interaction effect was found between DVES level and storage period on meat brightness, highlighting DVES to decrease the reduction in brightness during the first week of chill storage. While DVES significantly reduced meat yellowness, it did not change its redness regardless of storage period.

Changes in sources of shared variability of body size and shape in Egyptian local and New Zealand White breeds of rabbits during growth

Abstract. Correlations between body weight and measurements (body length, thigh circumference, shank length and chest width) at 6, 8, 10 and 12 weeks of age in New Zealand White (NZW), Red Baladi (RB), Black Baladi (BB) breeds of rabbits were studied by factor analysis to disclose the main sources of shared variability, to deduce the factors that describe these characteristics and to quantify breed differences in morphometric size and shape variation during growth. Differences and similarities between NZW and Egyptian rabbit breeds in factors describing variations in size and shape characters are discussed. At marketing age, compared with local breeds (RB and BB), NZW had higher communality (proportion of variance for a variable that is shared in common by other variables) for chest width and lower communality for body weight and other body shape characters. Compared with NZW, Egyptian breeds varied more in size and less in shape characters. Finding indicated that most of the common variability in live performance traits could be accounted for by two factors with the influence of general factor preponderating. Irrespective of breed, the first factor at various ages was interpreted as a general size factor. The second factor varies with breed and stage of development. In NZW, this factor at all ages (6 to 12 weeks) was described as chest width factor. The second factor in RB was designated to chest width (at 6 and 8 weeks) and a shank length at 10 and 12 weeks. In BB, the second factor was designated to chest width (at 6 weeks), a shank length (at 8 and 10 weeks) and to thigh circumference (at 12 weeks). The importance of the general size factor in relation to the second factor (shape) changes with age. The contribution of the general size factor to the total variance decreased with age in both NZW and RB, but it showed irregular pattern in BB. While that of the second factor increased with advancing age from 6 to 12 weeks in RB and from 6 to 10 weeks in NZW.