Effect of selection for maternal and direct genetic effects on genetic improvement of litter size in swine

1993 ◽  
Vol 71 (11) ◽  
pp. 2891-2904 ◽  
Author(s):  
R. Roehe ◽  
B. W. Kennedy
Keyword(s):  
Litter Size ◽  
Genetic Improvement ◽  
Genetic Effects ◽  
Selection For

Relationship between litter size and perinatal and pre-weaning survival in pigs

2002 ◽  
Vol 74 (2) ◽  
pp. 217-222 ◽  
Author(s):  
M. S. Lund ◽  
M. Puonti ◽  
L. Rydhmer ◽  
J. Jensen
Keyword(s):  
Litter Size ◽  
Negative Correlation ◽  
Genetic Effects ◽  
Direct Effects ◽  
Selection For ◽  
Heritability Estimates ◽  
The Relationship ◽  
Piglet Survival

AbstractThe objective of this study was to analyse the relationship between direct and maternal genetic effects on litter size and piglet survival. The analyses were performed on records from 26 564 Landrace litters and 15 103 Yorkshire litters from first parity dams in Finnish herds. The trivariate model fitted total number of piglets born, proportion alive at birth and proportion survived from birth until 3 weeks as traits of the litter. The model included direct genetic and maternal genetic effects for all traits. In Landrace pigs, maternal heritabilities were estimated to be 0·11 for total number born, 0·06 for proportion alive at birth, and 0·08 for proportion survived from birth until 3 weeks. The corresponding estimates for the Yorkshire breed were 0·14, 0·06 and 0·01. All heritability estimates of direct effects were below 0·05. In the Landrace breed, there was a negative correlation of -0·39 between maternal genetic effects on total number born and maternal genetic effects on proportion survived from birth until 3 weeks and a negative correlation of -0·41 between direct and maternal genetic effects on proportion survived from birth until 3 weeks. These correlations were not significant in the Yorkshire breed. The results show that selection for number born in total alone will lead to a deterioration in the maternal ability of sows. Selection for pre-weaning survival could be achieved by selecting on direct and maternal components jointly.

The effect of selection for litter size and litter weight at weaning in mice maintained on two diets

1963 ◽  
Vol 5 (3) ◽  
pp. 317-326 ◽  
Author(s):  
D. C. Dalton ◽  
T. L. Bywater
Keyword(s):  
Litter Size ◽  
Genetic Improvement ◽  
Random Mating ◽  
The Other ◽  
Response To Selection ◽  
Control Groups ◽  
Litter Weight ◽  
Dietary Switch ◽  
Selection For ◽  
Time Selection

SUMMARYAn experiment was carried out with mice over 24 generations to measure the response obtained to selection for litter size and litter weight at weaning on two dietary regimes designated normal and diluted. In addition, control groups bred by random mating were maintained on each diet. The stock were maintained on the diets from generation 0–3 after which time selection for the traits started and continued up to generation 17. After generation 17 for a further 6 generations, all selection stopped and half of each group was switched on to the other diet, while the remaining half continued as before.No significant response was obtained to selection for either litter size or litter weight at weaning.The diets provided did not bring about a differential response to selection for the traits, and the response to the dietary switch was small and temporary in its effect.Due to strong maternal effects and low heritability, little genetic improvement was obtained by selection for litter size and litter weight at weaning in these mice.

scholarly journals Additive Genetic Effects of RNF4, RBP4, and IGF2 Polymorphisms on Litter Size in Landrace and Yorkshire Sows

2019 ◽  
Vol 2 (1) ◽  
pp. 314-320 ◽  
Author(s):  
Vinh Thi Nguyen ◽  
Luc Duc Do ◽  
Thinh Hoang Nguyen ◽  
Bo Xuan Ha ◽  
Mai Ngoc Hoang ◽  
...  
Keyword(s):  
Litter Size ◽  
Reproductive Traits ◽  
Genetic Effects ◽  
Additive Effects ◽  
Selection For ◽  
Additive Genetic Effects

The association of the RNF4, RBP4, and IGF2 genotypes and their additive genetic effects with litter size in purebred Landrace and Yorkshire sows were studied. The results revealed significant associations between the RNF4 and RBP4 genotypes with the total number of piglets born (TNB) and number of piglets born alive (NBA) traits (P <0.05). The RNF4 CC genotype had greater TNB and NBA than the TT genotype in both breeds. The RBP4 BB genotype had greater TNB and NBA than the AA genotype in the Landrace breed. Significant additive effects of the RNF4 and RBP4 genes on the TNB and NBA were detected (P <0.05). No significant associations of the IGF2 genotypes and their additive effects with any reproductive traits were observed in both Landrace and Yorkshire sows (P >0.05). The results suggested that the RNF4 and RBP4 genes could be useful in selection for increasing TNB and NBA traits in pigs.

Selection indices for rabbit improvement

1986 ◽  
Vol 107 (3) ◽  
pp. 537-548
Author(s):  
M. H. Khalil ◽  
J. B. Owen ◽  
E. A. Afifi
Keyword(s):  
Litter Size ◽  
Genetic Gain ◽  
Genetic Improvement ◽  
Large Contribution ◽  
Litter Weight ◽  
Selection Indices ◽  
Selection For ◽  
Lower Contribution ◽  
Size At Birth

SUMMARYRecords on 884 litters and 3051 bunnies of the Bauscat (B) and Giza White (G) breeds were used to construct different selection indices.A series of selection indices and subindices were constructed for both B and G does. An index or subindex based on litter size at weaning, mean bunny weight at weaning, litter size at birth and litter weight at birth could be practically applied to improve the productivity of B and G does, under local Egytian conditions. Preweaning mortality did not contribute significantly to the different selection indices and subindices. Litter weight at birth made a large contribution to the different indices and subindices constructed. Litter size at weaning contributed little in the subindices to be used to select for mean bunny weight at weaning. Mean bunny weight at weaning made a lower contribution to the subindices to be used to select for litter size at weaning. The expected genetic gain in litter size at weaning was slight in all of the selection indices and subindices constructed because of low heritability values for this trait. Considerable genetic improvement for doe productivity of the G breed might be achieved through selection for mean bunny weight at weaning.Four selection indices and subindices were constructed for B and G rabbits. The index or subindex based on 6-week weight and 8-week weight was the best criterion for selection for the genetic improvement of 6-week weight and 12-week weight. Six- and 8-week weight contributed substantially while 12-week weight contributed little to the value of most of the selection indices and subindices constructed. The highest total genetic gain attributable to 6- and 12-week weight was obtained when the selection indices or subindices including 6-week weight and 8-week weight were used.

Correlated response to selection for litter size in pigs: II. Carcass, meat, and fat quality traits

2002 ◽  
Vol 80 (10) ◽  
pp. 2566 ◽  
Author(s):  
J. Estany ◽  
D. Villalba ◽  
M. Tor ◽  
D. Cubiló ◽  
J. L. Noguera
Keyword(s):  
Litter Size ◽  
Correlated Response ◽  
Quality Traits ◽  
Response To Selection ◽  
Fat Quality ◽  
Selection For

Selection and response within the nucleus of a sheep group-breeding scheme

1990 ◽  
Vol 51 (3) ◽  
pp. 593-599 ◽  
Author(s):  
S. Anderson ◽  
M. K. Curran
Keyword(s):  
Litter Size ◽  
Age Groups ◽  
Selection Response ◽  
Sheep Flock ◽  
Breeding Scheme ◽  
Average Value ◽  
Group Breeding ◽  
Selection For ◽  
Progeny Group ◽  
Selection Differentials

ABSTRACTAn evaluation of the response to selection for prolificacy within a nucleus sheep flock of a commercial group-breeding scheme is presented. In 1979, the Romney Group Breeders formed a nucleus flock of 120 prolific ewes chosen from 12 contributing flocks. A control flock was established in 1982 from the same source. The analysis was conducted on the trait of litter size. Selection differentials are presented for each year of birth progeny group in both flocks. Expected selection response was calculated from selection differentials and was found to have an average value of 1·5% of parent mean litter size per year. Using least squares procedures the litter size performance of control and nucleus ewes of 2, 3 and 4 years of age was corrected for environmental effects. Realized response was estimated from the differences between corrected litter size means of control and nucleus flocks. Response in litter size was found to be significant within years and within ewe age groups (P < 0·05).

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