Genetic analysis of maternal ability in Iberian pigs

Rodrı́guez, Carmen; Rodrigáñez, J.; Silió, L.

doi:10.1111/j.1439-0388.1994.tb00461.x

Cited by 20 publications

(15 citation statements)

References 12 publications

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“…Estimated genetic parameters of W4w, with a low heritability of direct effects, a much larger maternal heritability and a moderate genetic antagonism between direct and maternal effects, are consistent with early literature results (reviewed by Robison [35]). They are also similar to the results obtained at 3 weeks of age by Rodriguez et al [36] in Iberian pigs (with a lower antagonism between direct and maternal effects) and at 4 weeks of age by Maignel et al ([26] and unpublished results) in Large White and Landrace breeds. These results suggest that piglet preweaning growth is to a larger extent under the control of the environment provided by the dam than of the piglets' individual genes.…”

Section: Discussionsupporting

confidence: 80%

Genetic parameters and genetic trends in the Chinese × European Tiameslan composite pig line. I. Genetic parameters

Zhang

Bidanel

Burlot³

et al. 2000

Genet Sel Evol

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-Genetic parameters of body weight at 4 (W4w), 8 (W8w) and 22 (W22w) weeks of age, days from 20 to 100 kg (DT), average backfat thickness at 100 kg (ABT), teat number (TEAT), number of good teats (GTEAT), total number of piglets born (TNB), born alive (NBA) and weaned (NW) per litter, and birth to weaning survival rate (SURV) were estimated in the Chinese × European Tiameslan composite line using restricted maximum likelihood methodology applied to a multiple trait animal model. Performance data from a total of 4 881 males and 4 799 females from 1 341 litters were analysed. Different models were fitted to the data in order to estimate the importance of maternal effects on production traits, as well as genetic correlations between male and female performance. The results showed the existence of significant maternal effects on W4w, W8w and ABT and of variance heterogeneity between sexes for W22w, DT, ABT and GTEAT. Genetic correlations between sexes were 0.79, 0.71 and 0.82, respectively, for W22w, DT and ABT and above 0.90 for the other traits. Heritability estimates were larger than (ABT and TEAT) or similar to (other traits) average literature values. Some genetic antagonism was evidenced between production traits, particularly W4w, W8w and ABT, and reproductive traits.

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Section: Discussionsupporting

confidence: 80%

Genetic parameters and genetic trends in the Chinese × European Tiameslan composite pig line. I. Genetic parameters

Zhang

Bidanel

Burlot³

et al. 2000

Genet Sel Evol

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“…In Iberian pigs, Rodríguez et al (1994) found that the litters and individual piglets heaviest at weaning are those born in the second parity and, thereafter, a negative effect of parity on piglet and litter weight is observed. More recently, Fernández et al (2005) from analyses fitting random regression models described a similar negative relationship between litter weight at weaning (maternal ability) and parity order.…”

Section: Discussionmentioning

confidence: 99%

Sex Ratio Variation in Iberian Pigs

Toro¹,

Fernández²,

García-Cortés³

et al. 2006

Genetics

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Within the area of sex allocation, one of the topics that has attracted a lot of attention is the sex ratio problem. Fisher (1930) proposed that equal numbers of males and females have been promoted by natural selection and it has an adaptive significance. But the empirical success of Fisher's theory remains doubtful because a sex ratio of 0.50 is also expected from the chromosomal mechanism of sex determination. Another way of approaching the subject is to consider that Fisher's argument relies on the underlying assumption that offspring inherit their parent's tendency in biased sex ratio and therefore that genetic variance for this trait exists. Here, we analyzed sex ratio data of 56,807 piglets coming from 550 boars and 1893 dams. In addition to classical analysis of heterogeneity we performed analyses fitting linear and threshold animal models in a Bayesian framework using Gibbs sampling techniques. The marginal posterior mean of heritability was 2.63 3 10 À4 under the sire linear model and 9.17 3 10 À4 under the sire threshold model. The probability of the hypothesis p(h 2 ¼ 0) fitting the last model was 0.996. Also, we did not detect any trend in sex ratio related to maternal age. From an evolutionary point of view, the chromosomal sex determination acts as a constraint that precludes control of offspring sex ratio in vertebrates and it should be included in the general theory of sex allocation. From a practical view that means that the sex ratio in domestic species is hardly susceptible to modification by artificial selection.T HE theory of sex allocation predicts, given that an organism reproduces sexually, how it should allocate resources to male and female functions and constitutes one of the most popular topics in evolutionary biology. It involves many related questions such as parental investment or mating systems and there is a vast array of theoretical and empirical literature on these predictions (Charnov 1982;Frank 1990). Here we focus on one of the topics that has attracted a lot of attention within the area of sex allocation: how individuals adjust the proportion of their offspring that are male (the sex ratio problem). Fisher (1930) proposed that equal numbers of males and females have been promoted by natural selection and it has an adaptive significance. His argument is that in a population with a biased sex ratio, parents with a genetic tendency to produce more progenies of the rarer sex attain a higher average number of grandchildren, and therefore the biased sex ratio will disappear.In mammals, males are the heterogametic (XY) and females are the homogametic (XX) sex. Therefore when male and female gametes unite randomly, half of the resulting zygotes will be XY and differentiate as males and the other half will be XX and differentiate as females. As a consequence the expected primary sex ratio, defined as the proportion of males at conception, is also expected to be 0.50 although with a substantial variance corresponding to the binomial distribution. Because the same sex ratio (0...

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“…According to the estimated parity effects on LW21, the best mothering ability of Torbiscal sows is achieved at parity 2 and it slightly decreases in the later parities, being similar the maternal aptitude of sows at the parities 1 and 5. Moreover, in this Iberian line the parity effect on individual piglet weight at 21 days is also maximum at parity 2 and decreases monotonically even after the parity 6 (Rodríguez et al, 1994).…”

Section: Analysis With Repeatability Animal Model (Rm)mentioning

confidence: 94%

“…An increase of litter size at birth up to fifth parity has been previously reported in Torbiscal and other Iberian pig strains by Pérez-Enciso and Gianola (1992) and Rodríguez et al (1994). Mothering ability measured by LW21 may be considered as a composite trait, combining litter size and average piglet weight at 21 days, which depend on the number of piglets born and the piglets preweaning survival and growth.…”

Section: Analysis With Repeatability Animal Model (Rm)mentioning

confidence: 99%

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Genetic parameters for litter size and weight at different parities in Iberian pigs

Fernández¹,

Rodrigáñez²,

Zuzúarregui³

et al. 2008

Span. j. agric. res.

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Genetic progress for reproductive performance in pigs is limited by mothering ability. It is a critical aspect for dam lines, in which litter weight at weaning could be included with litter size in the selection goal. Our objective was to investigate in Iberian pigs the genetic basis of the number of alive born piglets (NBA) and the litter weight at 21days (LW21) over the successive parities (t). Records for NBA were available from 6,775 litters born from 1,893 sows of the Torbiscal line, and LW21 records proceeded from 1,431 sows and 2,963 litters without crossfostering. Genetic parameters were estimated using an animal model with repeatability, a multi-trait animal model, and a random regression model. Estimated values of heritabilities for NBA and genetic correlations between parities confirm a partially different genetic control of prolificacy at parity 1 and at later parities. Results for LW21 indicate that this trait may be partially controlled by different genes at the first two parities and at the later ones. Estimated genetic parameters for NBA (t = 1), NBA (t ≥ 2), LW21 (t ≤ 2) and LW21 (t ≥ 3) were: heritability, h 2 = 0.15, 0.12, 0.22 and 0.15, respectively, and coefficient of permanent environmental effects, p 2 = 0.05, 0.02 and 0.24, respectively for the three last traits. The values of genetic correlations ranged from 0.44 to 0.84. A multitrait approach would be useful to estimate accurate genetic parameters, and to improve the low persistency of reproductive performance in the later parities of Iberian sows.Additional key words: genetic correlation, maternal ability, prolificacy, random regression model. ResumenEvaluación genética del tamaño y peso de camada para sucesivos partos en cerdas Ibéricas La mejora genética de la eficiencia reproductiva en cerdos está limitada por su aptitud maternal. Es éste un aspecto crítico en las líneas maternas, en las que el peso de la camada al destete podría ser incluido junto al tamaño de camada en el objetivo de selección. El objetivo del trabajo fue investigar en cerdos Ibéricos la base genética del núme-ro de lechones nacidos vivos (NBA) y el peso de camada a 21días (LW21) a lo largo de los sucesivos partos (t). Se dispuso de registros de NBA de 6.775 camadas nacidas de 1.893 cerdas, y registros de LW21 procedentes de 1.431 cerdas y 2.963 camadas sin adopciones. Se estimaron parámetros genéticos mediante tres modelos: con repetibilidad, multicarácter y de regresión aleatoria. Los valores de las heredabilidades y las correlaciones genéticas entre NBA en diferentes partos confirman su control genético, parcialmente distinto en el parto primero y posteriores. Los resultados para LW21 indican que este carácter puede estar parcialmente controlado por diferentes genes en los dos primeros partos y en los sucesivos. Los parámetros genéticos estimados para NBA (t = 1), NBA (t ≥ 2), LW21 (t ≤ 2) y LW21 (t ≥ 3) fueron: heredabilidad, h 2 = 0,15, 0,12, 0,22 y 0,15, respectivamente, y coeficiente de efectos de ambiente permanente, p 2 = 0,05, 0,02 y 0,24, respec...

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Genetic analysis of maternal ability in Iberian pigs

Cited by 20 publications

References 12 publications

Genetic parameters and genetic trends in the Chinese × European Tiameslan composite pig line. I. Genetic parameters

Genetic parameters and genetic trends in the Chinese × European Tiameslan composite pig line. I. Genetic parameters

Sex Ratio Variation in Iberian Pigs

Genetic parameters for litter size and weight at different parities in Iberian pigs

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