Estimation of genetic trends for weaning weight and teat number in Iberian pigs using mixed model methodology

Bejar, Feleciano R.; Rodríguez, M. C.; Toro, M. Á.

doi:10.1016/0301-6226(93)90005-3

Cited by 13 publications

(4 citation statements)

References 20 publications

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“…The influence of the piglet genotype on growth increases after the first 3 weeks when feed is supplied. B ejar et al (1993), using an animal model without maternal effects, found in the same strain the following parameters for piglet weight at 50 days: h 2 A = 0.10 ± 0.01 and c 2 = 0.27 ± 0.01.…”

Section: Resultsmentioning

confidence: 90%

Genetic analysis of maternal ability in Iberian pigs

Rodrı́guez¹,

Rodrigáñez²,

Silió³

1994

J Animal Breeding Genetics

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A practical measure of milk yield of the sow is the weight of the litter at three weeks of age when the piglet growth is entirely dependent on the milking ability of the dam. Genetic parameters of litter size at birth (LS) and litter weight at 21 days (LW21) were estimated using a DFREML procedure from records of 4883 litters (2,049 for LW21) of Iberian breed. Preliminary analysis showed negligible maternal genetic effects. The model for both traits included the fixed effects of farrowing period (86 levels), parity (6) and inbreeding coefficients of dam (Fd) and litter (F(1) ) as co-variables, and three random effects-additive genetic value, permanent environmental effect and residual on both traits. Heritability and repeatability estimates were 0.064 and 0.126 (LS) and 0.163 and 0.270 (LW21) respectively. Estimated genetic and phenotypic correlations were 0.214 and 0.043. The inbreeding depression per 10 % increase of Fd or F(1) was -0.150 or -0.170 in live piglets and -0.983 or -1.023 kg of litter weight. When the model for LW21 included the dam inbreeding and the number of suckling piglets as co-variables, the heritability and repeatability estimates were 0.243 and 0.431 respectively. A complementary analysis was carried out on individual records (weight at 21 days) of 26206 piglets farrowed by 1317 sows. The model included the fixed effects of sex, farrowing period, parity, and the inbreeding coefficients of dam and individual, as co-variables. A total of four random effects were also included: direct and maternal genetic effects, common environmental effects and residual. Estimates of heritability, maternal heritability and common environmental coefficient were, respectively, 0.019, 0.163 and 0.128, reinforcing the evidence of genetic variance for milk producing ability in Iberian sows. The estimated values of inbreeding depression for piglet weight at 21 days were -0.072 and -0.098 kg per 10 % increase in dam or litter inbreeding. ZUSAMMENFASSUNG: Genetische Analyse von Muttereigenschaften iberischer Schweine Ein praktisches Maß für Milchleistung von Sauen ist das Drei-Wochen-Wurfgewicht, das völlig von der Muttermilchleistung abhängt. Genetische Parameter für Geburtswurfgröße (LS) und Geburtswurfgewicht bei 21 Tagen (LW21) wurden mit DFREML von 4883 Würfen (2049 für LW21) geschätzt. Vorläufige Analysen zeigten vernachläßigbare maternale Wirkungen. Das Modell enthält fixe Wirkungen der Wurfperiode (86), Wurffolge (6) und Inzuchtkoeffizienten von Muttersau (Fd) und Wurf (F(1) ) als Ko-variable und dazu drei zufällige Wirkungen: additiv-genetischer Wert, permanenter Umwelteinfluß und der Rest, bei beiden Merkmalen. Heritabilität und Wiederholbarkeit wurden auf 0,064 und 0,126 (LS) und auf 0,163 und 0,270 (LW21) geschätzt. Genetische und phänotypische Korrelationen waren 0,214 bzw. 0,043. Inzuchtdepression pro 10 % für Fd bzw. Fl waren -0,15 bzw. -0,17 bei lebenden Ferkeln und -0,983 bzw. -1,023 Kg in Wurfgewicht. Wenn im Modell für LW21 Mutterinzucht und Zahl saugender Ferkel berücksichtigt wurde, waren die H...

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Section: Resultsmentioning

confidence: 90%

Genetic analysis of maternal ability in Iberian pigs

Rodrı́guez¹,

Rodrigáñez²,

Silió³

1994

J Animal Breeding Genetics

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“…Finally, a weak selection for weaning weight and teat number was also performed (Béjar et al . ), and it could have affected the relationship between heterozygosity and inbreeding in some genomic regions.…”

Section: Discussionmentioning

confidence: 99%

Measuring inbreeding and inbreeding depression on pig growth from pedigree or SNP‐derived metrics

Silió¹,

Rodríguez²,

Barragán³

et al. 2013

J Animal Breeding Genetics

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104

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Multilocus homozygosity, measured as the proportion of the autosomal genome in homozygous genotypes or in runs of homozygosity, was compared with the respective pedigree inbreeding coefficients in 64 Iberian pigs genotyped using the Porcine SNP60 Beadchip. Pigs were sampled from a set of experimental animals with a large inbreeding variation born in a closed strain with a completely recorded multi-generation genealogy. Individual inbreeding coefficients calculated from pedigree were strongly correlated with the different SNP-derived metrics of homozygosity (r = 0.814-0.919). However, unequal correlations between molecular and pedigree inbreeding were observed at chromosomal level being mainly dependent on the number of SNPs and on the correlation between heterozygosities measured across different loci. A panel of 192 SNPs of intermediate frequencies was selected for genotyping 322 piglets to test inbreeding depression on postweaning growth performance (daily gain and weight at 90 days). The negative effects on these traits of homozygosities calculated from the genotypes of 168 quality-checked SNPs were similar to those of inbreeding coefficients. The results support that few hundreds of SNPs may be useful for measuring inbreeding and inbreeding depression, when the population structure or the mating system causes a large variance of inbreeding.

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“…Since then, full pedigrees have been recorded, and no new blood has been introduced. Although the conservation of genetic resources was considered in the genetic strategy of the program, a moderate empirical selection in favor of weaning weight was applied initially ( Béjar et al 1993).…”

Section: Methodsmentioning

confidence: 99%

Genealogical Analysis of a Closed Herd of Black Hairless Iberian Pigs

Toro

Rodrigáñez

Silió

et al. 2000

Conservation Biology

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Livestock breeds are recognized as important components of world biodiversity. The Iberian pig is a swine breed well adapted to the Mediterranean forest ecosystem and provides cured products of high quality. The ancient population of Iberian pigs ( Sus scrofa meridionalis ) was differentiated in several local types, the black hairless pigs representing the fattest genetic type. The conservation program of the Guadyerbas strain has maintained this germplasm isolated since 1945 as a closed population in an experimental herd. The complete pedigree, with 1000 breeding animals descending from 24 founders, has been used to measure along the successive cohorts of breeding animals the effective number of founders, effective number of nonfounders, founder genome equivalents, and expected number of founders' surviving alleles. For the last cohort, the values were 10.34, 1.42, 1.25, and 4.06, respectively. The evolution of inbreeding and coancestry and its components attributable to each founder were also studied. The rate of increase in inbreeding and coancestry was 2.21% per cohort, or 0.906% per year. Finally, the effect of family structure and mating tactics on the evolution of coancestry was also analyzed. The greatest rates of coancestry per cohort were attributable to unbalanced family sizes, and the use of minimum coancestry matings effectively delayed the increase in inbreeding. Análisis Genealógico de una Manada Aislada del Cerdo Ibérico Lampiño NegroResumen: Las razas de ganado son consideradas como un componente importante de la biodiversidad mundial. El cerdo Ibérico es una raza de cerdos bien adaptada al ecosistema forestal del Mediterráneo y provee productos encurtidos de alta calidad. La población ancestral del cerdo Ibérico ( Sus scrofa meridionalis ) era diferenciada en diversos tipos locales, siendo los cerdos lampiños negros los representantes del tipo genético más gordo. El programa de conservación de la variedad Guadyerbas ha mantenido su germoplasma aislado desde 1945 como una población cerrada en una manada experimental. El pedigrí completo con 1000 animales reproductores descendientes de 24 fundadores ha sido usado para medir a lo largo de cohortes sucesivas de animales reproductores el número efectivo de fundadores, el número efectivo de no-fundadores, el genoma fundador equivalente y el número esperado de alelos fundadores sobrevivientes. Para la última cohorte, los valores fueron 10.34, 1.42, 1.25 y 4.06, respectivamente. También estudiamos la evolución de endogamia y codescendencia y sus componentes debidos a cada fundador. La tasa de incremento en endogamia y codescendencia fue del 2.21% por cohorte, o el equivalente a 0.906 % por año. Finalmente, analizamos el efecto de la estructura familiar y las tácticas de apareamiento en la evolución de la codescendencia. Las tasas más grandes de codescendencia por cohorte fueron atribuibles a tamaños familiares desbalanceados y al uso mínimo de apareamientos de codescendientes, retardando efectivamente el incremento de la endogamia.

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Estimation of genetic trends for weaning weight and teat number in Iberian pigs using mixed model methodology

Cited by 13 publications

References 20 publications

Genetic analysis of maternal ability in Iberian pigs

Genetic analysis of maternal ability in Iberian pigs

Measuring inbreeding and inbreeding depression on pig growth from pedigree or SNP‐derived metrics

Genealogical Analysis of a Closed Herd of Black Hairless Iberian Pigs

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