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Efficiency Traits (efficiency + trait)

Distribution by Scientific Domains

Life Sciences	75%

Selected Abstracts

Effect of Stocking Weight and Stocking Density on Production of Hybrid Striped Bass (Sunshine) in Earthen Ponds in the Second Phase of a 2-Phase System

JOURNAL OF THE WORLD AQUACULTURE SOCIETY, Issue 1 2004
Louis R. D'Abramo
Sunshine bass from Phase I or pond production were graded into two weight classes, 3 and 5 g, and stocked into experimental earthen ponds at a density of either 8,649/ha or 11,120/ ha in a 2 × 2 factorial design. After stocking, the fish were fed a commercially manufactured feed (43.0-45.5% crude protein) twice daily to satiation for 17 mo. At harvest, mean survival ranged from 67.4 to 84.8% but was highest for the fish stocked at 5g. Average production Tor ponds stocked at 8,649/ha and 11,120/ha, regardless of stocking weight, was 4,506 kg/ha and 5350 kg/ha, respectively. Production and percentages of assigned weight classes were not significantly different among treatments as a result of wide variation among replicates. Using size-dependent market prices assigned to the different harvest size groups, an economic analysis revealed gross receipts, variable costs, and total costs for the 11,120/ha 5-g treatment. Net returns were not significantly different among the four treatments due to large variation among replicates per treatment. These results confirm that the traditional phase II of pond production can be eliminated in favor of a direct stocking of phase I fish into a single production phase and economically competes very well with traditional three-phase growout management. The potential reduction in turnover time of production units achieved through the direct stock practice is an efficiency trait that should translate into significantly higher returns and a greater profit over the long term. Further reduction of stocking density combined with a stocking weight greater than 5 g should translate into greater proportion of larger, higher valued fish at harvest and a growout period of 18-20 mo, rather than the 24-30 mo traditionally needed for the combined phase II and phase III of production. [source]

Linkage of microbial ecology to phenotype: correlation of rumen microbial ecology to cattle's feed efficiency

FEMS MICROBIOLOGY LETTERS, Issue 1 2008
Le Luo Guan
Abstract Linkage of rumen microbial structure to host phenotypical traits may enhance the understanding of host,microbial interactions in livestock species. This study used culture-independent PCR-denaturing gradient gel electrophoresis (PCR-DGGE) to investigate the microbial profiles in the rumen of cattle differing in feed efficiency. The analysis of detectable bacterial PCR-DGGE profiles showed that the profiles generated from efficient steers clustered together and were clearly separated from those obtained from inefficient steers, indicating that specific bacterial groups may only inhabit in efficient steers. In addition, the bacterial profiles were more likely clustered within a certain breed, suggesting that host genetics may play an important role in rumen microbial structure. The correlations between the concentrations of volatile fatty acids and feed efficiency traits were also observed. Significantly higher concentrations of butyrate (P<0.001) and valerate (P=0.006) were detected in the efficient steers. Our results revealed potential associations between the detectable rumen microbiota and its fermentation parameters with the feed efficiency of cattle. [source]

Polymorphisms in the STAT6 gene and their association with carcass traits in feedlot cattle

ANIMAL GENETICS, Issue 6 2009
G. Rincon
Summary Identification of the genes and polymorphisms underlying quantitative traits, and understanding how these genes and polymorphisms affect economic traits, are important for successful marker-assisted selection and more efficient management strategies in commercial cattle populations. Signal transducer and activator of transcription 6 (STAT6) gene is tightly connected to IL-4 and IL-13 signalling and plays a key role in TH2 polarization of the immune system. In addition, STAT6 acts as a mediator of leptin signalling and has been associated with body weight regulation. The objective of this study was to determine if SNPs within the bovine STAT6 gene are associated with economically important traits in feedlot cattle. The approach consisted of resequencing STAT6 using a panel of DNA from unrelated animals of different beef breeds. Specifically, 16 kb of STAT6 was resequenced in 47 animals and the process revealed 39 SNPs. From the 39 SNPs, a panel of 15 tag SNPs was genotyped in 1500 beef cattle samples with phenotypes to perform a marker-trait association analysis. Among the 15 tag SNPs, five and six were polymorphic in Bos taurus and Bos indicus respectively. An association analysis was performed between the 15 tag SNPs and 14 performance and production traits. SNP ss115492459:C > A, ss115492461:A > G and ss115492458:G > C were significantly associated with back fat, calculated yield grade, cutability, hot carcass weight, dry matter intake, days on feed, back fat rate and average daily gain. These three SNPs were present in all Bos taurus beef breeds examined. Our results provide evidence that polymorphisms in STAT6 are associated with carcass and growth efficiency traits, and may be used for marker-assisted selection and management in feedlot cattle. [source]

Quantitative trait loci with effects on feed efficiency traits in Hereford × composite double backcross populations

ANIMAL GENETICS, Issue 6 2009
G. C. Márquez
Summary Two half-sib families of backcross progeny were produced by mating F1 Line 1 Hereford (L1) × composite gene combination (CGC) bulls with L1 and CGC cows. Feed intake and periodic weights were measured for 218 backcross progeny. These progenies were genotyped using 232 microsatellite markers that spanned the 29 BTA. Progeny from L1 and CGC females was analysed separately using composite interval mapping to find quantitative trait loci (QTL) affecting daily dry matter intake (DMI), average daily gain (ADG), feed conversion (FCR) and residual feed intake (RFI). Results from both backcrosses were pooled to find additional QTL. In the backcross to L1, QTL were detected for RFI and DMI on BTA11, FCR on BTA16, and ADG on BTA9. In the backcross to CGC, QTL were detected for RFI on BTA10, FCR on BTA12 and 16 and ADG on BTA15 and 17. After pooling, QTL were detected for RFI on BTA 2, 6, 7, 10, 11, 13 and 16; for FCR on BTA 9, 12, 16, 17 and 21; for ADG on BTA 9, 14, 15, 17; and for DMI on BTA 2, 5, 6, 9, 10, 11, 20 and 23. [source]