Indices of cellular development in muscles of lambs are influenced by sire estimated breeding values and pastoral nutritional system

2006 ◽  
Vol 57 (6) ◽  
pp. 651 ◽  
Author(s):  
P. L. Greenwood ◽  
G. E. Gardner ◽  
R. S. Hegarty
Keyword(s):  
Muscle Growth ◽  
Genetic Selection ◽  
Inverse Association ◽  
Semitendinosus Muscle ◽  
Eye Muscle ◽  
Weaning Weight ◽  
Breeding Values ◽  
Sire Group ◽  
Selection For ◽  
Estimated Breeding Values

This study examined influences of sire (n = 9) estimated breeding values (EBVs), sire-group (Muscle, Growth, and Control), and nutrition (low and high quality and availability pasture) from birth to slaughter at ~8 months of age on indices of muscle cellularity and transcriptional and translational capacity in 56 castrate lambs. Effects of nutritional systems to 8 months of age were greater, overall, than those due to EBVs or sire-group. Amount of DNA increased with increasing EBV for post-weaning eye muscle depth (PEMD or Muscle EBV) in longissimus but not in semimembranosus and semitendinosus muscles, while Muscle EBV also had an inverse association with concentration of DNA. Protein to DNA and RNA to DNA were related positively to Muscle EBV, the associations being strongest for the semitendinosus muscle. Post-weaning weight (PWWT or Growth) EBV correlated positively with the RNA to DNA ratio and, among high but not low nutrition lambs, was inversely related to concentration of muscle DNA, whereas post-weaning fat depth (PFAT or Fat) EBV was correlated positively with RNA concentration. Overall, the magnitude of effects of sire-group was less than for sire EBVs, presumably due to differing selection pressures for muscling, fatness, and growth. High nutrition lambs had more protein to DNA than low nutrition lambs in the longissimus and semitendinosus muscles, but not in the semimembranosus muscle. In low compared with high nutrition lambs, concentration of DNA was greater in the longissimus and semitendinosus muscles. Total amount of DNA was reduced by more in low compared with high nutrition in the longissimus and semimembranosus than in the semitendinosus, and amount of protein was reduced by more in low compared with high nutrition in the longissimus than in the other two muscles. We conclude that genetic selection for eye muscle depth in sheep has differing effects on cellular characteristics of the longissimus, semimembranosus, and semitendinosus muscles, and has greater effects on muscle cellular characteristics than genetic selection for post-weaning weight or fat depth.

Lamb myofibre characteristics are influenced by sire estimated breeding values and pastoral nutritional system

2006 ◽  
Vol 57 (6) ◽  
pp. 627 ◽  
Author(s):  
P. L. Greenwood ◽  
G. E. Gardner ◽  
R. S. Hegarty
Keyword(s):  
Cross Sectional Area ◽  
Eating Quality ◽  
Longissimus Muscle ◽  
Relative Area ◽  
Sectional Area ◽  
Semitendinosus Muscle ◽  
Cross Sectional ◽  
Eye Muscle ◽  
Breeding Values ◽  
Estimated Breeding Values

The objective of this study was to establish the extent to which lamb myofibre characteristics at ~8 months of age were influenced by sire (n = 9) estimated breeding values (EBVs) and pasture-based nutritional systems (low and high quality and availability, LOW and HIGH) from birth to slaughter (n = 56). Immunostaining of myosin heavy chain isoforms in longissimus muscle fibres revealed that as the post-weaning eye muscle depth EBV (PEMD) increased, the percentage of type 2B/X myofibres increased and the percentage of type 2A myofibres decreased. The percentage of type 2B/X myofibres also increased with increasing PEMD in the semimembranosus muscle, but not in the semitendinosus muscle. Post-weaning fat depth (PFAT) EBV was negatively related with the percentage of type 2B/X myofibres in longissimus and semitendinosus muscles and with the relative area of more glycolytic to more oxidative fibre types, although there was an interaction with nutritional system in the semitendinosus muscle, with this ratio increasing with the PFAT EBV among the LOW nutrition lambs. Overall, post-weaning weight (PWWT) EBV had less effect on myofibre characteristics than PEMD and PFAT EBVs. Average cross-sectional area of myofibres was more affected by the LOW than HIGH nutritional system in longissimus muscle (–25%) compared with semitendinosus (–21%) and semimembranosus (–15%) muscles. LOW nutrition resulted in a significantly smaller cross-sectional area of all myofibre types in longissimus muscle and of types 2A, 2AB/X, and 2B/X in semimembranosus and semitendinosus muscles. Overall, the relative area of glycolytic myofibres increased and/or more oxidative myofibre types decreased in LOW compared with HIGH nutritional system lambs in longissimus and semimembranosus, but not in semitendinosus muscle. The results demonstrate significant influences of sire EBVs on myofibre characteristics of lambs, the extent of which depends upon muscle type and nutritional regimen. More specifically, they suggest continued selection for increased muscling and reduced fatness in lambs are associated with shifts in the proportions of myofibre types, with potential for adverse effects on eating quality. They also show that the direction and magnitude of the effects of chronic, moderate postnatal nutritional restriction at pasture on myofibre characteristics vary between muscles with different contractile, metabolic, and/or functional characteristics.

Sheep of divergent genetic merit for wool growth do not differ in digesta kinetics while on restricted intakes

2014 ◽  
Vol 54 (9) ◽  
pp. 1243 ◽  
Author(s):  
I. De Barbieri ◽  
R. S. Hegarty ◽  
V. H. Oddy ◽  
M. C. Barnett ◽  
L. Li ◽  
...  
Keyword(s):  
Compartmental Model ◽  
Genetic Selection ◽  
Amino Nitrogen ◽  
Feeding Level ◽  
Wool Growth ◽  
Selection For ◽  
Fleece Weight ◽  
Estimated Breeding Values ◽  
Growth Differences ◽  
Weight Groups

Sheep selected for high wool growth were previously shown to exhibit higher microbial protein outflow from the rumen and higher uptake of amino nitrogen in portal blood than those selected for low wool growth. This suggests that genetic selection for wool growth may induce changes in foregut physiology. This study was undertaken to determine whether differences in digesta kinetics, especially mean retention mime (MRT), are associated with differences in fleece production between sheep with low or high estimated breeding values (EBVs) for fleece weight. Twenty mature Merino wethers with uniform EBVs for liveweight were allocated to two groups of 10 animals on the basis of high or low EBVs for yearling fleece weight. Five sheep with low-EBVs and five sheep with high-EBVs for fleece weight groups were allocated in a crossover design to low and high feeding-level treatments, which comprised a blended hay diet fed at maintenance or 1.5 times maintenance. All sheep were given single doses of chromium-mordanted fibre and cobalt-EDTA as inert, non-digestible markers. Digesta kinetics was determined by analysis of the faecal marker excretion patterns using a compartmental model. Higher feed intakes from animals fed 1.5 times maintenance were associated with higher rates of wool growth and higher masses of indigestible fibre in the gut, but reduced MRT of digesta. Although sheep with higher EBVs for fleece weight had higher wool growth rates, there was no indication that these wool growth differences were associated with differences in digesta kinetics. The lack of interaction between feeding level and genotype suggests that MRT did not contribute to genotype differences in wool growth in sheep fed restricted intakes. The differences in wool growth among commercial Merino sheep with divergent fleece weight EBVs achieved by multi-trait selection are not attributable to differences in digesta kinetics, at least when feed is not available ad libitum.

scholarly journals Weaning results of beef Hungarian Fleckvieh calves 2. Genetic parameters, breeding values

2010 ◽  
Vol 53 (1) ◽  
pp. 26-36 ◽  
Author(s):  
S. Bene ◽  
I. Füller ◽  
A. Fördős ◽  
F. Szabó
Keyword(s):  
Genetic Parameters ◽  
Correlation Coefficients ◽  
Breeding Value ◽  
Phenotypic Variance ◽  
Weaning Weight ◽  
Breeding Values ◽  
Estimated Breeding Values ◽  
Genetic Value ◽  
Maternal Heritability ◽  
Daily Gain

Abstract. Weaning weight, preweaning daily gain and 205-day weight of Hungarian Fleckvieh calves (n=8 929, bulls =4 539, heifers =4 390) born from 232 sires between 1980 and 2003 were examined. Variance, covariance components and heritability values and correlation coefficients were estimated. The effect of the maternal permanent environment on genetic parameters and breeding values were examined. Two animal models were used for breeding value estimation. The direct heritability (hd2) of weaning weight, preweaning daily gain and 205-day weight was between 0.37 and 0.42. The maternal heritability (hm2) of these traits was 0.06 and 0.07. The direct-maternal correlations (rdm) were medium and negative −0.52 and −0.74. Contribution of the maternal heritability and maternal permanent environment to phenotype is smaller than that of direct heritabilities (hm2+c2< hd2). The ratio of the variance of maternal permanent environment in the phenotypic variance (c2) changed from 3 to 6 %. Estimated breeding values changed whether the permanent environmental effect of dam wasn’t taken into consideration but the rank of the animals was not modified. The genetic value for weaning results of Hungarian Fleckvieh population has increased since 1997.

Genetic evaluation of crossbred lamb production. 2. Breed and fixed effects for post-weaning growth, carcass, and wool of first-cross lambs

2005 ◽  
Vol 56 (5) ◽  
pp. 455 ◽  
Author(s):  
N. M. Fogarty ◽  
V. M. Ingham ◽  
A. R. Gilmour ◽  
L. J. Cummins ◽  
G. M. Gaunt ◽  
...  
Keyword(s):  
Fixed Effects ◽  
Mixed Model ◽  
Fibre Diameter ◽  
Carcass Weight ◽  
Eye Muscle ◽  
Weaning Weight ◽  
Breeding Values ◽  
Meat Colour ◽  
Fleece Weight ◽  
Sire Breed

The study evaluated post-weaning growth, carcass characteristics, and wool production of crossbred progeny of 91 sires from more than 7 maternal breeds (including Border Leicester, East Friesian, Finnsheep, Coopworth, White Suffolk, Corriedale, and Booroola Leicester). The sires were joined to Merino and Corriedale ewes at 3 sites over 3 years with 3 link sires in common at each site and year. Post-weaning weight at an average age of 200 days of 2841 ewes and 3027 wethers was analysed using mixed model procedures. The wethers were slaughtered at an average age of 214 days and carcass weight, fat, muscle, meat colour, and ultimate pH (24 h post-slaughter) were analysed. For ewes, hogget fleece weight, yield, fibre diameter, and faecal worm egg count (FEC) were analysed. Sire breed was significant (P < 0.01), with a range of 32.8–39.0 kg for post-weaning weight, 19.1–22.8 kg for hot carcass weight, and for carcass fat levels (11.1–17.2 mm at the GR site (FatGR) and 3.4–6.5 mm at the C site, adjusted to 22 kg carcass weight), with the East Friesian cross carcasses being very lean (FatGR 11.1 mm). Sire breed was significant for eye muscle area (P < 0.01) but not for eye muscle depth, meat colour L* (brightness), or ultimate pH. Sire breed was significant (P < 0.01) for greasy and clean fleece weight (CFW), yield, and fibre diameter (FD), with ranges of 0.9 kg (CFW) and 4.6 μm (FD). Sire breed was not significant for FEC. Type of birth and rearing classification was significant for most traits. National estimated breeding values for the sires that were entered by industry breeders indicated that they covered a range of genetic merit for most traits within their respective breeds and were generally representative of the maternal genetics available in the industry. Where there were large differences between the sire mean and breed mean breeding values the effects on crossbred progeny performance would be small and not expected to affect our conclusions about the breed differences reported. The results provide lamb producers with comparative information on sire breeds for growth, carcass and wool traits. The considerable variation among individual sires within the respective breeds will be reported in later papers.

scholarly journals Performance of steer progeny of sires differing in genetic potential for fatness and meat yield following postweaning growth at different rates. 2. Carcass traits

2009 ◽  
Vol 49 (6) ◽  
pp. 525 ◽  
Author(s):  
W. A. McKiernan ◽  
J. F. Wilkins ◽  
J. Irwin ◽  
B. Orchard ◽  
S. A. Barwick
Keyword(s):  
Production Systems ◽  
Carcass Traits ◽  
Quality Traits ◽  
Muscle Area ◽  
Eye Muscle ◽  
Meat Yield ◽  
Breeding Values ◽  
Genetic Potential ◽  
Estimated Breeding Values ◽  
Selection Of

The steer progeny of sires genetically diverse for fatness and meat yield were grown at different rates from weaning to feedlot entry and effects on growth, carcass and meat-quality traits were examined. The present paper, the second of a series, reports the effects of genetic and growth treatments on carcass traits. A total of 43 sires, within three ‘carcass class’ categories, defined as high potential for meat yield, marbling or both traits, was used. Where available, estimated breeding values for the carcass traits of retail beef yield (RBY%) and intramuscular fat (IMF%) were used in selection of the sires, which were drawn from Angus, Charolais, Limousin, Black Wagyu and Red Wagyu breeds, to provide a range of carcass sire types across the three carcass classes. Steer progeny of Hereford dams were grown at either conventional (slow: ~0.5 kg/day) or accelerated (fast: ~0.7 kg/day) rates from weaning to feedlot entry weight, with group means of ~400 kg. Accelerated and conventionally grown groups from successive calvings were managed to enter the feedlot at similar mean feedlot entry weights at the same time for the 100-day finish under identical conditions. Faster-backgrounded groups had greater fat levels in the carcass than did slower-backgrounded groups. Dressing percentages and fat colour were unaffected by growth treatment, whereas differences in ossification score and meat colour were explained by age at slaughter. There were significant effects of sire type for virtually all carcass traits measured in the progeny. Differences in hot standard carcass weight showed a clear advantage to European types, with variable outcomes for the Angus and Wagyu progeny. Sire selection by estimated breeding values (within the Angus breed) for yield and/or fat traits resulted in expected differences in the progeny for those traits. There were large differences in both meat yield and fatness among the types of greatest divergence in genetic potential for those traits, with the Black Wagyu and the Angus IMF clearly superior for IMF%, and the European types for RBY%. The Angus IMF progeny performed as well as that of the Black Wagyu for all fatness traits. Differences in RBY% among types were generally reflected by similar differences in eye muscle area. Results here provide guidelines for selecting sire types to target carcass traits for specific markets. The absence of interactions between growth and genetic treatments ensures that consistent responses can be expected across varying management and production systems.

scholarly journals Changes in genomic predictions when new information is added

2021 ◽  
Vol 99 (2) ◽  
Author(s):  
Jorge Hidalgo ◽  
Daniela Lourenco ◽  
Shogo Tsuruta ◽  
Yutaka Masuda ◽  
Stephen Miller ◽  
...  
Keyword(s):  
Single Step ◽  
Pedigree Information ◽  
Weaning Weight ◽  
Breeding Values ◽  
Core Group ◽  
Absolute Change ◽  
Angus Cattle ◽  
Average Maximum ◽  
Estimated Breeding Values ◽  
Genetic Evaluations

Abstract The stability of genomic evaluations depends on the amount of data and population parameters. When the dataset is large enough to estimate the value of nearly all independent chromosome segments (~10K in American Angus cattle), the accuracy and persistency of breeding values will be high. The objective of this study was to investigate changes in estimated breeding values (EBV) and genomic EBV (GEBV) across monthly evaluations for 1 yr in a large genotyped population of beef cattle. The American Angus data used included 8.2 million records for birth weight, 8.9 for weaning weight, and 4.4 for postweaning gain. A total of 10.1 million animals born until December 2017 had pedigree information, and 484,074 were genotyped. A truncated dataset included animals born until December 2016. To mimic a scenario with monthly evaluations, 2017 data were added 1 mo at a time to estimate EBV using best linear unbiased prediction (BLUP) and GEBV using single-step genomic BLUP with the algorithm for proven and young (APY) with core group fixed for 1 yr or updated monthly. Predictions from monthly evaluations in 2017 were contrasted with the predictions of the evaluation in December 2016 or the previous month for all genotyped animals born until December 2016 with or without their own phenotypes or progeny phenotypes. Changes in EBV and GEBV were similar across traits, and only results for weaning weight are presented. Correlations between evaluations from December 2016 and the 12 consecutive evaluations were ≥0.97 for EBV and ≥0.99 for GEBV. Average absolute changes for EBV were about two times smaller than for GEBV, except for animals with new progeny phenotypes (≤0.12 and ≤0.11 additive genetic SD [SDa] for EBV and GEBV). The maximum absolute changes for EBV (≤2.95 SDa) were greater than for GEBV (≤1.59 SDa). The average(maximum) absolute GEBV changes for young animals from December 2016 to January and December 2017 ranged from 0.05(0.25) to 0.10(0.53) SDa. Corresponding ranges for animals with new progeny phenotypes were from 0.05(0.88) to 0.11(1.59) SDa for GEBV changes. The average absolute change in EBV(GEBV) from December 2016 to December 2017 for sires with ≤50 progeny phenotypes was 0.26(0.14) and for sires with &gt;50 progeny phenotypes was 0.25(0.16) SDa. Updating the core group in APY without adding data created an average absolute change of 0.07 SDa in GEBV. Genomic evaluations in large genotyped populations are as stable and persistent as the traditional genetic evaluations, with less extreme changes.

scholarly journals Effect of dietary l-carnitine supplementation to sows during gestation and/or lactation on sow productivity, muscle maturation and lifetime growth in progeny from large litters

2020 ◽  
Vol 124 (1) ◽  
pp. 43-56
Author(s):  
Hazel B. Rooney ◽  
K. O’Driscoll ◽  
P. Silacci ◽  
G. Bee ◽  
J. V. O’Doherty ◽  
...  
Keyword(s):  
Birth Weight ◽  
Litter Size ◽  
Muscle Development ◽  
Genetic Selection ◽  
Carnitine Supplementation ◽  
Semitendinosus Muscle ◽  
Myosin Heavy Chain Genes ◽  
Selection For ◽  
Dietary Treatments ◽  
Size At Birth

AbstractGenetic selection for increased sow prolificacy has resulted in decreased mean piglet birth weight. This study aimed to investigate the effect of l-carnitine (CAR) supplementation to sows during gestation and/or lactation on sow productivity, semitendinosus muscle (STM) maturity and lifetime growth in progeny. Sixty-four sows were randomly assigned to one of the four dietary treatments at breeding until weaning: CONTROL (0 mg CAR/d), GEST (125 mg CAR/d during gestation), LACT (250 mg CAR/d during lactation) and BOTH (125 mg CAR/d during gestation and 250 mg CAR/d during lactation). The total number of piglets born per litter was greater for sows supplemented with CAR during gestation (17·3 v. 15·8 (sem 0·52); P < 0·05). Piglet birth weight (total and live) was unaffected by sow treatment (P > 0·05). Total myofibre number (P = 0·08) and the expression level of selected myosin heavy chain genes in the STM (P < 0·05) were greater in piglets of sows supplemented with CAR during gestation. Pigs from sows supplemented with CAR during gestation had lighter carcasses at slaughter than pigs from non-supplemented sows during gestation (83·8 v. 86·7 (sem 0·86) kg; P < 0·05). In conclusion, CAR supplementation during gestation increased litter size at birth without compromising piglet birth weight. Results also showed that the STM of piglets born to sows supplemented with CAR during gestation was more developed at birth. However, carcass weight at slaughter was reduced in progeny of sows supplemented with CAR during gestation. The CAR supplementation strategy applied during gestation in this study could be utilised by commercial pork producers to increase sow litter size and improve offspring muscle development.

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