Genetic relationships between seasonal tissue levels in Scottish Blackface ewes and lamb growth traits

2005 ◽  
Vol 81 (1) ◽  
pp. 11-21 ◽  
Author(s):  
N. R. Lambe ◽  
S. Brotherstone ◽  
M. J. Young ◽  
J. Conington ◽  
G. Simm
Keyword(s):  
Weight Gain ◽  
Birth Weight ◽  
Litter Size ◽  
Growth Traits ◽  
Genetic Relationships ◽  
Genetic Correlations ◽  
Muscle Weight ◽  
Litter Weight ◽  
Weight Gains ◽  
Lamb Growth

AbstractScottish Blackface ewes (no. = 308) were scanned four times per year using X-ray computed tomography (CT scanning) (pre-mating, pre-lambing, mid lactation and weaning), from 18 months to 5 years of age, giving a maximum of 16 scanning events per ewe. Total weights of carcass fat, internal fat and carcass muscle were estimated from the CT images at each scanning event. Lambs produced by these ewes were weighed at birth, mid lactation and weaning to calculate litter growth traits: litter birth weight; litter weight gain from birth until mid lactation; and litter weight gain from birth until weaning. Genetic (rg) and phenotypic (rp) correlations were estimated between ewe CT tissue traits and litter growth traits. Correlations between ewe CT tissue traits and litter size (LS) were also estimated. Ewe CT tissue traits were either unadjusted or adjusted for total soft tissue weight (sum of weights of carcass fat, internal fat and carcass muscle) to investigate relationships with either absolute tissue weights of carcass fat (CFWT), internal fat (IFWT), and carcass muscle (CMWT), or relative proportions of carcass fat (CFP), internal fat (IFP), and carcass muscle (CMP). Litter growth traits were either unadjusted or adjusted for litter size, to investigate relationships with total lamb burden (total litter birth weight (TBW), total litter weight gain from birth until mid lactation (TWGM), total litter weight gain from birth until weaning (TWGW)) or average lamb performance (average lamb birth weight (ABW), average lamb weight gain from birth until mid lactation (AWGM), average lamb weight gain from birth until weaning (AWGW)).Moderate to large positive genetic correlations were estimated between absolute weights of all three ewe tissues (CFWT, IFWT, CMWT), or muscle proportion (CMP), and litter size (LS). Significant positive genetic correlations were also estimated between weight (CMWT) or proportion (CMP) of muscle carried by the ewe pre-mating and total birth weight (TBW) and weight gains (TWGM, TWGW) of her litter, largely due to the associated increase in litter size. Muscle proportion (CMP) was not significantly correlated to average lamb weights or weight gains (ABW, AWGM, AWGW). Pre-lambing carcass fat weight (CFWT) and proportion (CFP) in the ewe showed positive genetic correlations with average lamb weights and weight gains (ABW, AWGM, AWGW), whereas, after lambing, CFP was negatively correlated with these lamb traits. Internal fat weight (IFWT) pre-mating showed positive genetic correlations with all litter growth traits (TBW, TWGM, TWGW, ABW, AWGM, AWGW). Average lamb growth traits were negatively correlated with pre-lambing internal fat proportion (IFP), but positively correlated to IFP at mid lactation and weaning.Correlations were also estimated between each pair of CT traits. Total internal fat weight and total carcass fat weight were very highly correlated (rp= 0·75,rg= 0·96). Correlations with total carcass muscle weight were smaller and positive for both carcass fat weight (rp= 0·48,rg= 0·12) and internal fat weight (rp= 0·42,rg= 0·20).The results suggest that selection for increased carcass muscle weight or proportion in a Scottish Blackface hill flock would have a positive effect on total weights of litters reared, but that selection against carcass fat weight or proportion in a breeding programme for Blackface sheep may have an impact on the maternal ability of the ewe. However, maintaining fat in internal depots may reduce the depletion of carcass fat during pregnancy, allowing this depot to provide energy for lactation, and may have a positive impact on lamb growth.

The performance of Masham ewes

1979 ◽  
Vol 29 (1) ◽  
pp. 69-79 ◽  
Author(s):  
J. E. Newton ◽  
J. S. Fenlon
Keyword(s):  
Growth Rate ◽  
Birth Weight ◽  
Perinatal Mortality ◽  
Litter Size ◽  
High Birth Weight ◽  
Litter Weight ◽  
Lamb Growth

ABSTRACTThe performance of two flocks of crossbred Masham ewes (Tees-water × Dales Bred) was measured for 6 and 4 years respectively. The ewes in Flock 1 were mated with Dorset Down rams and the ewes in Flock 2 with Suffolk rams.The overall mean mating weight of each flock was 68-0 kg with no consistent year-to-year variation. The mating weight repeatability values for ewes entering the flocks as 2-year-olds were 0·532 (±0·0681) and 0·524 (±0·1118) for Flocks 1 and 2 respectively.Mean litter size increased with age, but repeatability was low. Over- all litter weights for singles, twins and triplets were 5·89, 9·88 and 12·43 kg respectively. Two-year-old ewes had lighter litters than mature ewes. Repeatability for litter weight in Flock 1 was 0·337 (±0·0755).Lamb growth rate to 4 weeks of age was lower for 2-year-old ewes in both flocks and the repeatability was 0·322 (±0·0947) in Flock 1. For ewes having twin lambs, significant correlations (P < 0·01) were found between mating weight and birth weight and between birth weight and lamb growth rate to 4 weeks of age.Perinatal mortality was higher for lambs with a birth weight below 3·9 kg, but overall lamb mortality was only 8%: this low figure was probably due to the relatively high birth weight of the twin and triplet lambs.

Composite trait selection to improve reproduction and ewe productivity: a review

2009 ◽  
Vol 49 (1) ◽  
pp. 9 ◽  
Author(s):  
G. D. Snowder ◽  
N. M. Fogarty
Keyword(s):  
Individual Component ◽  
Genetic Relationships ◽  
Reproductive Efficiency ◽  
Component Trait ◽  
Litter Weight ◽  
Growth Selection ◽  
Component Traits ◽  
Selection For ◽  
Genetic Responses ◽  
Lamb Growth

Reproduction and ewe productivity are complex composite traits that are influenced by several component traits. Genetic improvement by selection for an individual component trait may not always be advantageous because adverse or neutral genetic relationships can exist among the component traits. Selection for an overall composite trait of ewe productivity, defined as litter weight weaned per ewe joined, can result in a balanced biological composite trait with favourable responses in component traits including fertility, number of lambs born, lamb survival, lactation and lamb growth. Selection for litter weight weaned may also overcome adverse genetic relationships among reproductive component traits. This review examines the genetic responses of selecting directly for litter weight weaned, compared with selection responses for one or more of its component traits. It is concluded that selection to improve reproductive efficiency and ewe productivity, under most production and environmental systems, would benefit from selection for a composite trait such as litter weight weaned, rather than for a single component trait.

Genetic parameters for daily live-weight gain, live fleshiness and bone thinness in station-tested Piemontese young bulls

2001 ◽  
Vol 72 (3) ◽  
pp. 449-456 ◽  
Author(s):  
A. Albera ◽  
R. Mantovani ◽  
G. Bittante ◽  
A. F. Groen ◽  
P. Carnier
Keyword(s):  
Weight Gain ◽  
Genetic Parameters ◽  
Growth Traits ◽  
Genetic Correlations ◽  
Live Weight ◽  
Adaptation Period ◽  
Production Traits ◽  
Multiple Trait ◽  
Live Weight Gain ◽  
Total Gain

AbstractEstimates of genetic parameters for beef production traits were obtained for Piemontese cattle. Data were from 988 young bulls station-tested from 1989 till 1998. Bulls entered the station at 6 to 8 weeks of age and, after an adaptation period of 3 months, were tested for growth, live fleshiness and bone thinness. Length of test was 196 days. Growth traits considered were gain at farm, gain during the adaptation period, gain on test and total gain at the station. Six different fleshiness traits and bone thinness were scored on live animals at the end of the test using a linear system. Live evaluations of fleshiness were adjusted for the weight at scoring in order to provide an assessment of conformation independent of body size. Genetic parameters were estimated using animal models. Heritability of live-weight gain ranged from 0·20 in the adaptation period to 0·60 for total gain at the station. Genetic correlations between gains at station in different periods were high (from 0·63 to 0·97). Residual correlation between gain during the adaptation period and gain during test was negative, probably due to the occurrence of compensatory growth of the animals.Live fleshiness traits and bone thinness were of moderate to high heritability (from 0·34 to 0·55) and highly correlated indicating that heavy muscled bulls also have thin bones. Accuracy of breeding values and therefore response to selection were improved by multiple trait analysis of the live fleshiness traits and bone thinness. Overall weight gain at the station had a moderate negative genetic correlation with all live fleshiness traits and bone thinness (from –0·11 to –0·39).

Genetic evaluation of crossbred lamb production. 4. Genetic parameters for first-cross animal performance

2007 ◽  
Vol 58 (8) ◽  
pp. 839 ◽  
Author(s):  
V. M. Ingham ◽  
N. M. Fogarty ◽  
A. R. Gilmour ◽  
R. A. Afolayan ◽  
L. J. Cummins ◽  
...  
Keyword(s):  
Genetic Variation ◽  
Meat Quality ◽  
Mixed Models ◽  
Fixed Effects ◽  
Growth Traits ◽  
Genetic Correlations ◽  
Fibre Diameter ◽  
Quality Traits ◽  
Meat Quality Traits ◽  
Lamb Growth

The study estimated heritability for lamb growth and carcass performance, hogget ewe wool production, and worm egg count among crossbred progeny of maternal breed sires, as well as the genetic and phenotypic correlations among the traits. The data were from crossbred progeny of 91 sires from maternal breeds including Border Leicester, East Friesian, Finnsheep, Coopworth, White Suffolk, Corriedale, and Booroola Leicester. The sires were mated to Merino ewes at 3 sites over 3 years (and also Corriedale ewes at one site), with 3 common sires used at each site and year to provide genetic links. These sheep comprised part of the national maternal sire central progeny test program (MCPT) to evaluate the genetic variation for economically important production traits in progeny of maternal and dual-purpose (meat and wool) sires and the scope for genetic improvement. The matings resulted in 7846 first-cross lambs born, with 2964 wether lambs slaughtered at an average age of 214 days, and wool data from 2795 hogget ewes. Data were analysed using univariate mixed models containing fixed effects for site, year, sex and type of birth and rearing, dam source and sire breed, and random terms for sire and dam effects. Heritabilities and genetic correlations were estimated based on variances from progeny of 70 sires by fitting the same mixed models using a REML procedure in univariate and multivariate analyses. Estimates of heritability were low for lamb growth traits (0.07–0.29), meat colour and meat pH (0.10–0.23), and faecal worm egg count (0.10), moderate for carcass fat and muscle traits (0.32–0.47), and moderate to high for wool traits (0.36–0.55). Estimates of direct genetic correlations among liveweights at various ages were high and positive (0.41–0.77) and those between liveweights and most carcass and meat quality traits were small and varied in sign. Liveweights were moderately to highly positively correlated with most wool traits, except fibre diameter (–0.28–0.08). The study indicates that there is genetic variation for wool, growth, carcass, and meat quality traits, as well as for faecal worm egg count, with scope for selection within Australian maternal sire breeds of sheep.

Comparative farrowing to weaning performance in Meishan and Large White pigs and their crosses

1995 ◽  
Vol 60 (2) ◽  
pp. 269-280 ◽  
Author(s):  
G. J. Lee ◽  
C. S. Haley
Keyword(s):  
Birth Weight ◽  
Standard Deviation ◽  
Litter Size ◽  
Large White ◽  
Weaning Weight ◽  
Growth And Survival ◽  
Probability Of Survival ◽  
Litter Weight ◽  
Litter Traits ◽  
Breed Differences

AbstractGrowth and survival from birth to weaning were monitored during three generations of crossbreeding between British Large White (LW) and Chinese Meishan (MS) pigs. The design allowed comparisons between sow genotypes ranging from zero to all MS genes, which were mated toLWor MS boars, to produce progeny with proportions of 0·0 to 0·5 or 0·5 to 1·0 MS genes, respectively. Crossbreeding parameters of both maternal and direct piglet performance were estimated for the first two parities using restricted maximum likelihood (REML) methods for litter traits (litter weight at birth, litter mean and within litter standard deviation of piglet weight at birth, proportion surviving to weaning, litter size and weight at weaning and litter mean piglet weight at weaning) and for traits of the piglet (birth weight, probability of survival and weaning weight). For litter traits, the estimated contribution of the additive maternal effect to the breed differences (MS-LW) was significant for litter mean piglet birth weight (–0·46 (s.e. 0·04) kg), survival to weaning (0·15 (s.e. 0·02)), litter size at weaning (1·6 (s.e. 0·16) piglets), litter weaning weight (–11·2 (s.e. 3·8) kg) and litter mean piglet weaning weight (2·54 (s.e. 0·24) kg). Adding litter size and litter mean piglet birth weight to the model removed the additive maternal contribution to the breed differences in survival, and litter size and reduced that for litter mean piglet weaning weight. The contribution of the direct additive effect to the breed difference (MS-LW) was significant for the within litter standard deviation in birth weight (0·018 (s.e. 0·006)), survival to weaning (0·12 (s.e. 0·02)) and litter size (1·12 (s.e. 0·64)) and weight (11·6 (s.e. 4·0) kg) at weaning, but not for piglet weight at birth or weaning. Fitting litter size and litter mean birth weight had comparatively little impact on the direct additive effects. There were significant maternal heterosis effects for litter weight at birth and litter size and weight at weaning, the estimated deviation of the F1 from the midpoint of the two purebreds 3·22 (s.e. 0·55) kg, 2·20 (s.e. 0·47) piglets, and 20·1 (s.e. 3·3) kg respectively, but none for survival or piglet weights. There were direct heterosis effects for litter weight and litter mean piglet weights, the estimated deviation of the Fjfrom the mid point of the two purebreds being 1·16 (s.e. 0·41) kg and 0·14 (s.e. 0·02) kg, for survival to weaning (0·04 (s.e. 0·02)) and for litter weight (11·2 (s.e. 2·5) kg) and litter mean piglet weight (0·96 (s.e. 0·17) kg) at weaning. Fitting litter size and litter mean piglet birth weight removed or reduced both maternal and direct heterosis effects. Individual piglet analyses gave similar results to analyses of the equivalent sow trait. It was concluded that in litters born to MS cows, the lower piglet survival and lower weaning weights were related to the larger litter sizes and lower piglet birth weights. For their birth weight, however, MS piglets have a greater ability to survive and thrive. The large direct and maternal heterosis effects observed for litter and mean piglet weight at weaning werepartly associated with the heavier birth weight of the crossbred piglet.

Genetic correlations for reproductive and growth traits in rabbits

2020 ◽  
Vol 100 (2) ◽  
pp. 317-322 ◽  
Author(s):  
Rym Ezzeroug ◽  
Rafik Belabbas ◽  
Maria José Argente ◽  
Ali Berbar ◽  
Samir Diss ◽  
...  
Keyword(s):  
Litter Size ◽  
Coefficient Of Variation ◽  
Growth Traits ◽  
Genetic Correlations ◽  
Reproductive Traits ◽  
High Coefficient ◽  
Genetic And Phenotypic Correlations ◽  
The Common ◽  
Large Coefficient ◽  
Size At Birth

The objective of this study was to obtain heritability estimates for reproductive (litter size at birth, number born alive, litter size at weaning) and growth traits (individual weaning weight, individual weight at the end of the fattening period), then determine the genetic correlation between them in a synthetic rabbit line. A total of 805 females, 3242 parities, and 18 472 growth records were measured from 2006 to 2017. A pentavariate animal model was used with reproductive and growth traits. Heritability ranged from 0.025 to 0.126 for reproductive traits and from 0.033 to 0.059 for growth traits. These traits showed a large coefficient of variation (from 32% to 56% for reproductive traits and from 21% to 28% for growth traits). The repeatability of reproductive traits was low and the common litter effect for growth traits was the most important component of total variance. The genetic and phenotypic correlations between reproductive and growth traits were high and negative, especially with weight at weaning (−0.848, −0.922, and −0.854 for litter size at birth, number born alive, and litter size at weaning, respectively). In conclusion, because of the high negative correlation between reproductive and growth traits, both reproductive and growth traits should be selected in independent lines and the response to selection should be due mainly to the high coefficient of variation of the traits.

scholarly journals Relationships between body reserve dynamics and rearing performances in meat ewes1

2019 ◽  
Vol 97 (10) ◽  
pp. 4076-4084
Author(s):  
Tiphaine Macé ◽  
Dominique Hazard ◽  
Fabien Carrière ◽  
Sebastien Douls ◽  
Didier Foulquié ◽  
...  
Keyword(s):  
Genetic Relationships ◽  
Genetic Correlations ◽  
Repeated Measurements ◽  
Production Cycle ◽  
Data Sets ◽  
Data Set ◽  
Litter Weight ◽  
Significant Relationships ◽  
Physiological Stage ◽  
Changes Over Time

Abstract The main objective of this work was to study the relationships between body reserve (BR) dynamics and rearing performance (PERF) traits in ewes from a Romane meat sheep flock managed extensively on “Causse” rangelands in the south of France. Flock records were used to generate data sets covering 14 lambing years (YR). The data set included 1,146 ewes with 2 ages of first lambing (AGE), 3 parities (PAR), and 4 litter sizes (LS). Repeated measurements of the BW and BCS were used as indicators of BR. The ewe PERF traits recorded were indirect measurements for maternal abilities and included prolificacy, litter weight and lamb BW at lambing and weaning, ADG at 1, 2, and 3 mo after lambing, and litter survival from lambing to weaning. The effects of different BW and BCS trajectories (e.g., changes in BW and BCS across the production cycle), previously been characterized in the same animals, on PERF traits were investigated. Such trajectories reflected different profiles at the intraflock level in the dynamics of BR mobilization–accretion cycles. Genetic relationships between BR and PERF traits were assessed. All the fixed variables considered (i.e., YR, AGE, PAR, LS, and SEX ratio of the litter) have significant effects on the PERF traits. Similarly, BW trajectories had an effect on the PERF traits across the 3 PARs studied, particularly during the first cycle (PAR 1). The BCS trajectories only affected prolificacy, lamb BW at birth, and litter survival. Most of the PERF traits considered here showed moderate heritabilities (0.17–0.23) except for prolificacy, the lamb growth rate during the third month and litter survival which showed very low heritabilities. With exception of litter survival and prolificacy, ewe PERF traits were genetically, strongly, and positively correlated with BW whatever the physiological stage. A few weak genetic correlations were found between BCS and PERF traits. As illustrated by BW and BCS changes over time, favorable genetic correlations were found, even if few and moderate, between BR accretion or mobilization and PERF traits, particularly for prolificacy and litter weight at birth. In conclusion, our results show significant relationships between BR dynamics and PERF traits in ewes, which could be considered in future sheep selection programs aiming to improve robustness.

Estimates of genetic parameters for pre-weaning and post-weaning growth traits of Chios lambs

1980 ◽  
Vol 30 (2) ◽  
pp. 271-276 ◽  
Author(s):  
A. P. Mavrogenis ◽  
A. Louca ◽  
O. W. Robison
Keyword(s):  
Body Weight ◽  
Birth Weight ◽  
Genetic Parameters ◽  
Growth Traits ◽  
Genetic Correlations ◽  
Heritability Estimate ◽  
Weaning Weight ◽  
Phenotypic Correlations ◽  
Selection For ◽  
Daily Gain

ABSTRACTData on 792 Chios lambs born during the 1972/73 and 1973/74 lambing seasons were used to estimate genetic and phenotypic parameters for birth weight, weaning weight, age at weaning, pre-weaning daily gain, body weight at 5, 10, 15 and 20 weeks of age, and postweaning daily gain. Body weight at 15 weeks of age had the highest heritability estimate (0·73 ± 0·17) and that of post-weaning daily gain was also high (0·56 ± 0·15). Selection for either weight at 15 weeks or post-weaning daily gain would be expected to yield a greater response than selection for pre-weaning daily gain or weaning weight. Genetic correlations among weights and/or gains were positive (approximately 0·20). Phenotypic correlations among weights and gains were generally higher than genetic correlations. However, the correlation between pre— and post-weaning daily gain was small (0·08). Likewise, post-weaning daily gain had low correlations with all weights before 10 weeks. Age at weaning had moderate negative associations with all weights but a very low positive correlation with post-weaning daily gain.

ESTIMATES OF GENETIC CORRELATIONS AMONG CERTAIN CARCASS AND PERFORMANCE TRAITS IN SWINE

1968 ◽  
Vol 48 (1) ◽  
pp. 1-6 ◽  
Author(s):  
G. L. Roy ◽  
W. J. Boylan ◽  
M. E. Seale
Keyword(s):  
Birth Weight ◽  
Genetic Correlation ◽  
Genetic Relationships ◽  
Carcass Traits ◽  
Genetic Correlations ◽  
Development Project ◽  
Carcass Trait ◽  
Selection For ◽  
And Performance ◽  
Daily Gain

Data from a swine breed development project provided estimates of the genetic correlation among six performance and carcass traits. The data from the new breed, called Managra, were obtained over a 7-year period. Most genetic relationships examined were such that selection for improvement of one trait would yield a favorable improvement in another. Both carcass backfat and live backfat probe were found to be negatively correlated with area of loin eye and length of carcass. A positive genetic correlation was found between post-weaning daily gain and loin eye area. A high positive genetic correlation was found between birth weight and loin eye area. An unfavorable association involved a positive genetic correlation between birth weight and backfat.Correction factors for effect of carcass weight on the magnitude of carcass trait measurements and differences in means between sexes were obtained.Heritability of the traits was estimated by paternal half-sib correlation. The estimates for carcass traits were moderately high and agree well with most other estimates reported in the literature.

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