Efeitos genéticos e ambientais sobre a idade à primeira concepção de fêmeas suínas

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ABSTRACT. We evaluated genetic and environmental factors affecting age at first farrowing of sows in the Brazilian southeast. For this purpose, 466 observations regarding the age at first farrowing were made for Dalland-C40 © animals belonging to two herds. The effects of the environmental factors on this trait were assessed by means of a model that included, as random effects, the influence of the sow's father and mother and, as fixed effects, the influence the year of birth, the herd and the birth season, along with the covariable litter size at birth. The variance components were estimated using the derivative-free restricted maximum likelihood method. The estimated mean was 354.8 ± 25.87 days, with a coefficient of variation of 7.29%. Significant effects on the trait were observed for the herd, the year and the season of birth; Genetic and environment effects on age at first farrowing but a linear effect of litter size at birth on the age at first farrowing was not observed. The boar did not significantly contribute to the variation occurring among the sows, whereas the sow's mother caused significant variation. The heritability estimate for the age at first farrowing was 0.44 ± 0.15, which is considered high. We concluded that herd effect and year and season of birth should be taken into consideration for an accurate genetic comparison; consequently, the animals should be joined into contemporary groups.

Section: Discussionmentioning

confidence: 99%

Genetic and environmental effects on age at first farrowing in sows in southeastern Brazil

Cavalcante-Neto¹,

Lui²,

Sarmento³

et al. 2011

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“…Environmental and genetic factors may influence reproductive and productive traits of swine (Cavalcante-Neto et al, 2008a, 2009a. The WEI is usually associated with parity number, estrus length, the time of ovulation, and previous litter size (Karveliene et al, 2008;Cavalcante-Neto et al, 2008b), and it may be also influenced by other environmental factors such as season, temperature, photoperiod, nutrition, stress, age of the sow, management practices, genetic, among others (Antunes, 2007;Lundgren et al, 2010).…”

Section: Introductionmentioning

confidence: 99%

Environmental and genetic factors affecting the weaning-estrus interval in sows

Leite

Lui²,

Albuquerque³

et al. 2011

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ABSTRACT. We examined the effects of environmental and genetic factors on the weaning-to-estrus interval (WEI) in sows. In order to perform the analyses of the environmental factors, 8104 observations of the 1st to the 6th WEI were carried out, while 6548 observations of the 1st to the 3rd WEI were carried out for the analyses of genetic factors. The environmental model included as fixed effects, herd, genetic line, year and season of birth, as well as the covariates, age of sow at farrowing, litter size at birth and lactation length. Genetic analysis was performed by repeatability and multitrait models. The mean and coefficient of variation for WEI were 7.02 days and 100.6%, respectively. The linear effect of lactation length and the quadratic effect of the age of sow at farrowing affected the WEI. Herd, year and season of farrowing were significant sources of variation for WEI, and there was no influence of genetic line or of litter size at birth. Heritability estimated by the repeatability model was 0.04, while heritabilities obtained by the multitrait model were Factors affecting the weaning-estrus interval in sows 0.07, 0.02 and 0.07 for the first three WEI, respectively. Estimates of genetic correlations among the different WEI were of moderate to low magnitude. It was concluded that environmental factors, such as year and season of farrowing, lactation length, age of sow at farrowing and herd, should be considered in the model for best estimation of genetic parameters for this trait. Although with only a small possible genetic gain, selection can be made based on the first WEI.

“…The age at first mating is extremely important in farm stock since the gilts represent a large proportion of the animals; whereas the first parity may influence the reproductive efficiency of the herd (Cavalcante Neto et al, 2008;Rotava, 2014) and can increase the number of non-productive days. According to Whittmore and Kyriazakis (2006), selection of genotypes for lean meat and increased prolificity may have caused negative consequences, especially in primiparous females, mainly by the reduction of lipid deposition.…”

Section: Mc4r (Snpg1578c>t)mentioning

confidence: 99%

Research Article Association of MC4R, FABP3 and DGAT1 gene polymorphisms with reproductive traits in two domestic pig lines

Gondim¹,

Soares²,

Lugo³

et al. 2019

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MC4R, FABP3 and DGAT1 are important genes related to productive and reproductive traits in pigs, such as food intake, growth rate, back fat thickness reduction and lactation. Selection of pigs for lean meat production may lead to losses in reproductive charcters because reduction of backfat thickness and low feed intake during the lactation phase can affect reproduction. To examine this possibility, we evaluated possible associations of SNPs in the MC4R (SNPg.1,578C>T), FABP3 (SNPg.240T>C) and DGAT1 (SNPg.9,422C>T) genes with the number of weaned piglets, birth weight, total weight of litter at birth, total litter weight at weaning, age at first mating and parity interval in 227 animals of two maternal lines: European and European/Chinese pigs. Specific fragments of the genes under study were amplified by Multiplex ©FUNPEC-RP www.funpecrp.com.br Genetics and Molecular Research 18 (3): gmr18139 V.S. Gondim et al. 2 ARMS-PCR and genotyped in an automatic sequencer. SNPs in the MC4R (SNPg.1,578C>T) and FABP3 (SNPg-240T>C) genes showed three genotypic variations in both lines, while the SNP (SNPg.9,422C>T) of the DGAT1 gene had three genotypic variations in European swine and two genotypic variations (homozygotes) in the European/Chinese breed. Polymorphisms of MC4R, FABP3 and DGAT1 genes evaluated by variance analysis had significant associations with the reproductive traits age at first mating and parity interval, while only the DGAT1 gene in the European line was significantly associated with the production traits mean weight at weaning and total litter weight at birth andnd weaning.