Using blup to estimate responses est a sheep flock selected for litter size

1993 ◽  
Vol 1993 ◽  
pp. 105-105
Author(s):  
G.E. Pollott
Keyword(s):  
Litter Size ◽  
Reproductive Performance ◽  
Reproductive Traits ◽  
Phenotypic Variance ◽  
Sheep Flock ◽  
Sheep Population ◽  
Important Contributor ◽  
Selection Experiments ◽  
Genetic Trends

The reproductive performance of ewes is an important contributor to flock profitability in many different situations. Although the heritability of reproductive traits is low there is often enough phenotypic variance to make a consideration of selection a possibility for improvement in litter size. Genetic trends in selection experiments have traditionally been monitored using a control flock which should be kept as an unseletced group. The recent availability of user friedly BLUP programs have added an extra method for estimating genetic trends. This paper reports the use of BLUP to estimate the genetic trends in a sheep population selected for litter size.

scholarly journals Estimation of variance components, genetic parameters and genetic trends for litter size of swines

2010 ◽  
Vol 39 (10) ◽  
pp. 2155-2159 ◽  
Author(s):  
Leandro Barbosa ◽  
Paulo Sávio Lopes ◽  
Adair José Regazzi ◽  
Robledo de Almeida Torres ◽  
Mário Luiz Santana Júnior ◽  
...  
Keyword(s):  
Litter Size ◽  
Variance Components ◽  
Genetic Parameters ◽  
Random Effect ◽  
Additive Model ◽  
Fixed Effect ◽  
Likelihood Method ◽  
Phenotypic Variance ◽  
Estimation Of Variance ◽  
Genetic Trends

Records of Large White breed animals were used to estimate variance components, genetic parameters and trends for the character total number of born piglets (TNBP) as measure of litter size. For obtaining variance components and genetic parameters, it was used the Restricted Maximum Likelihood Method using MTDFREML software. Two mixed models (additive and repeatability) were evaluated. The additive model contained fixed effect of the contemporary group and the following random effects: direct additive genetic and residual effect for the first parturition. Repeatability model had the same effects of the additive model plus parturition order fixed effect and non-correlated animal permanent environment random effect for the second, third and forth parturition. Direct additive heritability estimates for TNBP were 0.15 and 0.20 for the additive and repeatability models, respectively. The estimate of the ration among variance of the non-correlated effect of animal permanent environment effect and the phenotypic variance, expressed as total variance proportion (c2) was 0.09. The estimates of yearly genetic trends obtained in the additive and repeatability models have similar behaviors (0.02 piglets/sow/year).

scholarly journals Effects of BF Gene Polymorphism on the Reproductive Performance of Hybrid Polish Landrace X Polish Large White Sows

2016 ◽  
Vol 66 (1) ◽  
pp. 125-131
Author(s):  
Dorota Napierała ◽  
Maria Kawęcka ◽  
Eugenia Jacyno ◽  
Beata Matysiak ◽  
Anita Kołodziej-Skalska
Keyword(s):  
Gene Polymorphism ◽  
Litter Size ◽  
Reproductive Performance ◽  
Reproductive Traits ◽  
Specific Primers ◽  
Large White ◽  
Potential Relationship ◽  
Pcr Rflp

AbstractThe aim of this study was to determine the potential relationship between variants of the BF gene and litter size in Polish Landrace x Polish Large White sows. To identify polymorphism within the BF gene, the PCR-RFLP method was applied, using specific primers and the SmaI enzyme. The researchers identified the presence of two alleles, T and C, with frequencies: 0.68 and 0.32, giving three genotypes with frequencies: 0.49, 0.37 and 0.14, respectively for TT, TC and CC. Analysis of relationships between the various genotypes of the BF gene and selected reproductive traits showed significant differences. Sows with TT genotype in the BF locus, gave birth to significantly more live piglets in the first litter (10.24) compared with sows with the CC genotype (7.13).

scholarly journals Genetic and Genomic Analyses of Service Sire Effect on Female Reproductive Traits in Holstein Cattle

2021 ◽  
Vol 12 ◽  
Author(s):  
Ziwei Chen ◽  
Luiz F. Brito ◽  
Hanpeng Luo ◽  
Rui Shi ◽  
Yao Chang ◽  
...  
Keyword(s):  
Dairy Cattle ◽  
Reproductive Performance ◽  
Reproductive Traits ◽  
Genetic Effects ◽  
Holstein Cattle ◽  
Phenotypic Variance ◽  
Breeding Values ◽  
Female Reproductive Traits ◽  
Success Traits ◽  
Calving Traits

Fertility and reproductive performance are key drivers of dairy farm profitability. Hence, reproduction traits have been included in a large majority of worldwide dairy cattle selection indexes. The reproductive traits are lowly heritable but can be improved through direct genetic selection. However, most scientific studies and dairy cattle breeding programs have focused solely on the genetic effects of the dam (GED) on reproductive performance and, therefore, ignored the contribution of the service sire in the phenotypic outcomes. This study aimed to investigate the service sire effects on female reproductive traits in Holstein cattle from a genomic perspective. Genetic parameter estimation and genome-wide association studies (GWAS) were performed for the genetic effect of service sire (GESS) on conception rate (CR), 56-day non-return rate (NRR56), calving ease (CE), stillbirth (SB), and gestation length (GL). Our findings indicate that the additive genetic effects of both sire and dam contribute to the phenotypic variance of reproductive traits measured in females (0.0196 vs. 0.0109, 0.0237 vs. 0.0133, 0.0040 vs. 0.0289, 0.0782 vs. 0.0083, and 0.1024 vs. 0.1020 for GESS and GED heritability estimates for CR, NRR56, CE, SB, and GL, respectively), and these two genetic effects are positively correlated for SB (0.1394) and GL (0.7871). Interestingly, the breeding values for GESS on insemination success traits (CR and NRR56) are unfavorably and significantly correlated with some production, health, and type breeding values (ranging from −0.449 to 0.274), while the GESS values on calving traits (CE, SB, and GL) are usually favorably associated with those traits (ranging from −0.493 to 0.313). One hundred sixty-two significant single-nucleotide polymorphisms (SNPs) and their surrounding protein-coding genes were identified as significantly associated with GESS and GED, respectively. Six genes overlapped between GESS and GED for calving traits and 10 genes overlapped between GESS for success traits and calving traits. Our findings indicate the importance of considering the GESS when genetically evaluating the female reproductive traits in Holstein cattle.

scholarly journals Influence of Small Ruminant Lentivirus Infection on Reproductive Traits in Ewes

2013 ◽  
Vol 57 (1) ◽  
pp. 15-18
Author(s):  
Czesława Lipecka ◽  
Andrej Junkuszew ◽  
Jacek Kuźmak ◽  
Tomasz M. Gruszeck ◽  
Bożena Kozaczyńska ◽  
...  
Keyword(s):  
Reproductive Performance ◽  
Small Ruminant ◽  
Reproductive Traits ◽  
Genetic Group ◽  
Sheep Flock ◽  
Research Results ◽  
Genetic Groups ◽  
Negative Effect

AbstractThe study included a sheep flock comprising five genetic groups. The ELISA was applied to perform constant monitoring (every six months) for the infection of ewes with small ruminant lentivirus (SRLV). The research results demonstrated a negative effect of SRLVs infection on lamb rearing that, depending on the genetic group, proved to be lower 1.3%-1.4% compared to the seronegative mothers. At relatively equal fertility (94%-100%) and more differentiated prolificacy (179%-198%) in all the examined groups (except the Suffolk breed), a rearing index was higher in the seronegative animals 6.8%-24.1% compared to the seropositive mothers. The Suffolk breed proved to be the genetic group most susceptible to SRLV infection. A prolificacy of infected ewes was 10% lower, a lamb rearing rate was 13% lower , and a general reproductive performance was 18% lower in comparison to healthy ewes.

Reproductive performance and genetic parameters for Australian Dorset Sheep

1994 ◽  
Vol 45 (2) ◽  
pp. 427 ◽  
Author(s):  
LD Brash ◽  
NM Fogarty ◽  
AR Gilmour
Keyword(s):  
Litter Size ◽  
Reproductive Performance ◽  
Genetic Improvement ◽  
Genetic Correlations ◽  
Reproductive Traits ◽  
Reproductive Rate ◽  
Parameter Estimates ◽  
Reproduction Traits ◽  
Component Traits ◽  
Lamb Survival

Reproductive performance of ewes in a large Dorset stud flock is reported. The data included 2488 ewes with 10016 joining records over 25 years. Average performance for reproductive traits were: fertility 92%, litter size 1.31, neonatal lamb survival 91%, lamb survival to weaning 85%, with overall lambs born 1.20 and lambs weaned 1.02 per ewe joined. Differences between breeds (Poll Dorset and Dorset Horn), season of birth (spring and autumn) and season of joining (spring and autumn) were significant for most reproduction traits. Linear and quadratic regressions for age of ewe at joining were highly significant for all traits (P < 0.001) with maximum performance between three and six years of age. Estimates of heritability for ewe reproductive traits were: 0.062 � 0-02 for number of lambs born and 0.04 � 0.01 for number of lambs weaned per ewe joined, and component traits, 0.02 �0 -01 for fertility, 0 08 � 0 -02 for litter size and 0.00 � 0.01 for lamb survival. Estimates of repeatability were less than 0.14 for all the reproduction traits, which resulted in substantially higher predicted heritabilities when repeated records were used. Heritability estimates for average ewe lifetime performance, with approximately four records, were 0.08 � 0 06 for lambs born, 0.12 � 0.05 for lambs weaned, 0.08 � 0.04 for fertility, 0.l9 � 0 -04 for litter size and zero for lamb survival. The genetic correlations between litter size and lambs born and weaned were close to unity, whereas those for fertility were lower and declined from lambs born (0.6l � 0.22) to lambs weaned (0-45 � 0.30). The estimated heritability for ewe longevity, defined as the number of years the ewe remained in the breeding flock, was 0.00 � 0.03. The potential for genetic improvement in reproductive rate is discussed in relation to other reports in the literature and in the context of the roles of the Dorset breed in the Australian lamb industry. Increased reproductive rate in Dorset flocks impacts on stud profitability and the rate of genetic improvement from selection for other traits such as liveweight. The parameter estimates derived will be used in compiling breed-specific parameter sets for genetic evaluation in LAMBPLAN.

Variation in reproduction and production of Poll Dorset ewes

1994 ◽  
Vol 45 (2) ◽  
pp. 415 ◽  
Author(s):  
DG Hall ◽  
AR Gilmour ◽  
NM Fogarty
Keyword(s):  
Litter Size ◽  
Environmental Effects ◽  
Reproductive Performance ◽  
Reproductive Traits ◽  
Late Summer ◽  
Reproductive History ◽  
Reproduction Traits ◽  
Lamb Survival ◽  
Fleece Weight ◽  
One Year

Poll Dorset ewes were joined to Booroola Merino (n = 22) or Trangie Fertility Merino (n = 26) rams in single sire joinings during late summer/autumn of 1978, 1979, 1980 and 1981. Rams were changed each year and there were 1678 individual ewe joinings. A maximum of 527 ewes were used in any one year, and they represented 14 studs and varied in age, reproductive history and liveweight. The traits, litter size, maternal lamb survival, lambs weaned per ewe lambing and weight of lamb weaned per ewe lambing (kg at 100 days) were analysed for the effect of year, stud, age, lambs born and ewe liveweight. Litter size averaged 1-37, maternal lamb survival 0.70, and number of lambs weaned per ewe was 0.94. There were large variations in the reproductive traits due to year and stud and lesser effects due to age. Each extra kilogram of ewe liveweight at joining increased litter size by 0.012 and weight of lamb weaned by 0.39 kg, but had no significant effect on maternal lamb survival or number of lambs weaned. Multiple-bearing ewes weaned 0.72 more lambs and 16 - 2 kg more lamb weight than single-bearing ewes. Lamb survival was similar for singleand multiple-bearing ewes. Greasy fleece weight averaged 2.2 kg ewe-' and single bearing ewes produced 0.19 kg/ewe more than multiple-bearing ewes. Dystocia caused 53% and starvation/mismothering/exposure caused 23% of lamb deaths; the proportion of deaths due to starvation/mismothering/exposure increased with increasing ewe joining liveweight. The large variation between studs in reproductive performance partly reflected genetic differences between Poll Dorset flocks which could be exploited. Estimates of heritabilities ranged from 0.06 to 0.14 � 0.10 for the reproductive traits and were 0.10 � 0.12 for ewe liveweight and 0.16 � 0.20 for greasy fleece weight. However much of the between stud variation may also have arisen from early environmental effects. Estimates of repeatability ranged from 0.06 to 0.l5 � 0 05 for reproduction traits and were 0.44 � 0.06 for ewe liveweight at joining and 0.56 � 0.08 for greasy fleece weight.

Bayesian estimation of genetic parameters of litter size at birth in crossbred Mule ewes using repeatability and multiple trait threshold models

2007 ◽  
Vol 2007 ◽  
pp. 66-66
Author(s):  
W. Mekkawy ◽  
R. Roehe ◽  
R. M. Lewis ◽  
M. H. Davies ◽  
A. M. Van Heelsum ◽  
...  
Keyword(s):  
Litter Size ◽  
Reproductive Performance ◽  
Genetic Parameters ◽  
Reproductive Traits ◽  
Threshold Models ◽  
Multiple Trait ◽  
Repeated Observations ◽  
Improvement Programs ◽  
Size At Birth ◽  
Estimation Of Genetic Parameters

The reproductive performance of ewes is a major factor influencing the economic success of lowland flocks. Even so reproductive traits have not often been included in sheep genetic improvement programs because of their low heritabilities compared with other performance traits like body weight and carcass merit. Litter size is one of the most important traits affecting reproductive performance. There are two important factors to be considered in the genetic analysis of litter size. First, several authors have suggested that litter size in different parities is controlled in part by different genes, and therefore should be treated as different traits. Second, ignoring the categorical nature of litter size and analysing it using a linear model does not account for its non-normal distribution. As a consequence, threshold models are likely to be more appropriate for the analysis of categorical traits (Gianola and Foulley, 1983). Therefore, the objective of the current study was to estimate the genetic parameters for litter size of Mule ewes using both repeatability and a multiple trait threshold models for repeated observations of litter size across four different parities.

The relationship between heterozygosity and heterosis in reproductive traits in mice

1980 ◽  
Vol 30 (1) ◽  
pp. 69-77 ◽  
Author(s):  
Patricia McGloughlin
Keyword(s):  
Linear Relationship ◽  
Litter Size ◽  
Reproductive Performance ◽  
Reproductive Traits ◽  
Total Weight ◽  
Positive Linear Relationship ◽  
Livestock Breeding ◽  
Distinct Strain ◽  
Outbred Mice ◽  
The Relationship

ABSTRACTContinuous reciprocal backcrossing results in individuals which are 67% heterozygous, and which, assuming a linear relationship between heterozygosity and heterosis, would be expected to exhibit 67% of the heterosis found in Fi hybrids. An experiment was undertaken to investigate this relationship in the reproductive traits of mice. By crossing and repeated backcrossing in both directions using two unrelated strains of outbred mice, females were produced which were 25, 50, 75 and 100% heterozygous. The crossbred females and the two purebred strains (922 females in all) were mated to a sire line of a genetically distinct strain to standardize foetal heterosis. The reproductive performance of females with different percentage heterozygosity gave estimates of maternal heterosis. A significant positive linear relationship was found between heterozy-gosity and heterosis in litter size, total weight of litter and individual weight of progeny both at birth and at weaning. The relevance of these results for livestock breeding is discussed.

scholarly journals VARIATIONS IN AND RELATIONSHIPS BETWEEN REPRODUCTIVE PERFORMANCE AND GROWTH PARAMETERS IN YEARLING BEEF BULLS IN SINGLE-SIRE MATING AT PASTURE

1989 ◽  
Vol 69 (1) ◽  
pp. 39-46
Author(s):  
A. FARID ◽  
M. MAKARECHIAN ◽  
R. T. BERG ◽  
M. A. PRICE
Keyword(s):  
Beef Cattle ◽  
Key Words ◽  
Pregnancy Rate ◽  
Breeding Season ◽  
Reproductive Performance ◽  
Growth Parameters ◽  
Reproductive Traits ◽  
Phenotypic Variance ◽  
Breed Group ◽  
Beef Bulls

Yearling bull fertility, measured as pregnancy rate, percentage of calves born during the first 4 and 6 wk of calving and mean and median of calving date distribution, were studied in 109 single-sire breeding herds of two breed groups over a 10-yr period. The breed groups were Herefords bulls mated to purebred and crossbred Hereford cows, and Beef Synthetic bulls mated to Beef Synthetic cows. The bulls averaged 14 mo old at the start of breeding. The average bull-to-cow ratio was approximately 1:22, and the breeding season started on 1 July each year and extended for 60 d. Two out of 109 bulls (1.8%) were subfertile (less than 50% pregnancy of the herd). The Beef Synthetic, which had crossbred foundation, had significantly higher fertility, calved earlier, had smaller phenotypic variance, and lower year-to-year fluctuation in the reproductive traits than the Hereford. Variations in reproductive performances of bulls of the same breed group used in the same year were much larger than those among different years, the former comprised over 75% of phenotypic variance of the traits in the two breed groups. Relationships between fertility of bulls and their weight and growth parameters were negligible, but bull fertility tended (P < 0.10) to improve with age. Bulls that were heavy at weaning, end of feedlot test and breeding settled their mates earlier during the breeding season. Key words: Beef cattle, yearling bull, fertility

REPRODUCTIVE PERFORMANCE OF GILTS FROM LINES SELECTED FOR FEED UTILIZATION AND CARCASS SCORE

1972 ◽  
Vol 52 (2) ◽  
pp. 267-271
Author(s):  
M. H. FAHMY ◽  
C. S. BERNARD
Keyword(s):  
Least Squares ◽  
Litter Size ◽  
Reproductive Performance ◽  
Reproductive Traits ◽  
Feed Utilization ◽  
Gestation Length ◽  
Litter Weight ◽  
Yorkshire Pigs ◽  
Score Line ◽  
Size At Birth

Eight reproductive traits were studied on 751 gilts of 3 lines of Yorkshire pigs derived from a common population by selecting for feed utilization (line 1), carcass score (line 2), and for both traits combined (line 3) during 10 generations. Least squares means for the traits were as follows: gestation length 115.2 days; litter size at birth 9.0 pigs (total) and 8.4 pigs (alive); litter size at weaning 6.8 pigs; number of teats 13.4; and litter weight at birth, 21, and 56 days, 9.3, 32.6, and 92.6 kg, respectively. Heritability estimates were calculated for each line by half-sib correlation and intra-sire regression of offspring on dam. The pooled estimate for the above eight traits was 0.45, 0.11, 0.09, 0.15, −0.12, 0.08, 0.14, and 0.14, respectively. Line effect was highly significant for all traits except litter size at birth. Means and heritabilities for line 3 were higher than those for lines 1 and 2, which did not differ greatly from each other. Variation from year to year had significant effects only on litter weight at different ages. The within years–within line regressions of the eight traits on inbreeding were not significant. The within line phenotypic correlations between each of feed utilization and carcass score and the eight traits were generally low and nonsignificant.

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