Lethal and semi-lethal mutations in Holstein calves in Uruguay / Mutações letais e semi-letais em bezerros da raça Holandesa no Uruguai

Genetic disorders in Holstein cattle are a health problem that has grown worldwide in recent years, compromising the sustainability of modern dairy production. In Uruguay, Holstein-based milk production is one of the most important sectors of the countrys economy, but high levels of inbreeding have decreased the breeds fertility in recent decades. This study investigated the presence and diffusion of lethal and semi-lethal alleles causing embryo death, abortions, fetal malformations, and neonatal diseases in Holstein calves. Using the GeneSeek® Genomic Profiler Bovine 50K BeadChip, we genotyped 383 calves (1-30 days-old) from 27 farms located in the main dairy region of Uruguay. Results showed a high prevalence of farms (85%) and carrier calves (21%), including one or more of the following semi-lethal or lethal alleles: Syndactylism (4.18%), brachyspina (3.39%), cholesterol deficiency haplotype (2.61%), complex vertebral malformation (2.09%), bovine leukocyte adhesion deficiency (1.04%s), and Holstein haplotypes HH1 (4.44%), HH3 (3.13%), HH4 (1.04%), and HH5 (0.26%). Most of these alleles had not been recognized previously in Uruguay. We concluded that lethal and semi-lethal mutations are widespread in the Holstein breed in Uruguay. More studies are required to determine their impact on dairy cattle fertility.(AU)

Os distúrbios genéticos nos bovinos da raça Holandesa são um problema de saúde que cresceu nos últimos anos a nível mundial, comprometendo a sustentabilidade da produção leiteira moderna. No Uruguai, a produção leiteira com base na raça Holstein é um dos setores mais importantes da economia do país, mas altos níveis de endogamia diminuíram a fertilidade da raça nas últimas décadas. O objetivo deste estudo foi investigar a presença e difusão de alelos letais e semi-letais causando morte de embriões, abortos, malformações fetais e doenças neonatais em bezerros da raça Holandesa. Usando o BeadChip Bovino 50K GeneSeek® Genomic Profiler, genotipamos 383 bezerros (menos de um mês) de 27 fazendas localizadas na principal região leiteira do Uruguai. Os resultados mostraram uma alta prevalência de fazendas (85%) e bezerros portadores (21%), incluindo um ou mais dos seguintes alelos letais ou semi-letais: sindactilismo (4,18%), braquipespina (3,39%), haplótipo de deficiência de colesterol (2,61%), malformação vertebral complexa (2,09%), deficiência de adesão de leucócitos bovinos (1,04% s) e haplótipos de Holstein HH1 (4,44%), HH3 (3,13%), HH4 (1,04%) e HH5 (0,26%). A maioria desses alelos não havia sido reconhecida anteriormente no país. Concluímos que as mutações letais e semi-letais são comuns na raça Holstein no Uruguai. Mais estudos são necessários para determinar seu impacto na fertilidade do gado leiteiro.(AU)

Carrier frequency of autosomal recessive disorders (BC, BLAD, FXID and CVM) in Holstein cows in Jalisco, Mexico

The hereditary autosomal recessive disorders bovine citrullinemia (BC), bovine leukocyte adhesion deficiency (BLAD), factor XI deficiency (FXID), and complex vertebral malformation (CVM) have affected dairy cattle breeding significantly around the world. This study examined the carrier frequency of BC, BLAD, FXID, and CVM autosomal recessive disorders in Bos taurus Holstein cows bred in the Altos Norte region of the state of Jalisco, Mexico. We extracted DNA from 408 random samples of peripheral blood, and then used polymerase chain reaction (PCR) to identify insertion mutations for FXID, and PCR with restriction fragment length polymorphism (PCR-RFLP) for CVM, BC and BLAD. We visualized the PCR products using agarose gel electrophoresis stained with GelRed®. We found that 100% of wild-type (N/N) allele homozygous animals for genes CD18, ASS, and FXI were free of the mutations for BLAD, BC and FXID respectively. For gene SLC35A3 we estimated total carrier frequency of 10.3% and allele frequency of 5%.(AU)

Carrier frequency of autosomal recessive disorders (BC, BLAD, FXID and CVM) in Holstein cows in Jalisco, Mexico

The hereditary autosomal recessive disorders bovine citrullinemia (BC), bovine leukocyte adhesion deficiency (BLAD), factor XI deficiency (FXID), and complex vertebral malformation (CVM) have affected dairy cattle breeding significantly around the world. This study examined the carrier frequency of BC, BLAD, FXID, and CVM autosomal recessive disorders in Bos taurus Holstein cows bred in the Altos Norte region of the state of Jalisco, Mexico. We extracted DNA from 408 random samples of peripheral blood, and then used polymerase chain reaction (PCR) to identify insertion mutations for FXID, and PCR with restriction fragment length polymorphism (PCR-RFLP) for CVM, BC and BLAD. We visualized the PCR products using agarose gel electrophoresis stained with GelRed®. We found that 100% of wild-type (N/N) allele homozygous animals for genes CD18, ASS, and FXI were free of the mutations for BLAD, BC and FXID respectively. For gene SLC35A3 we estimated total carrier frequency of 10.3% and allele frequency of 5%.(AU)

Carrier frequency of autosomal recessive disorders (BC, BLAD, FXID and CVM) in Holstein cows in Jalisco, Mexico

ABSTRACT: The hereditary autosomal recessive disorders bovine citrullinemia (BC), bovine leukocyte adhesion deficiency (BLAD), factor XI deficiency (FXID), and complex vertebral malformation (CVM) have affected dairy cattle breeding significantly around the world. This study examined the carrier frequency of BC, BLAD, FXID, and CVM autosomal recessive disorders in Bos taurus Holstein cows bred in the Altos Norte region of the state of Jalisco, Mexico. We extracted DNA from 408 random samples of peripheral blood, and then used polymerase chain reaction (PCR) to identify insertion mutations for FXID, and PCR with restriction fragment length polymorphism (PCR-RFLP) for CVM, BC and BLAD. We visualized the PCR products using agarose gel electrophoresis stained with GelRed®. We found that 100% of wild-type (N/N) allele homozygous animals for genes CD18, ASS, and FXI were free of the mutations for BLAD, BC and FXID respectively. For gene SLC35A3 we estimated total carrier frequency of 10.3% and allele frequency of 5%.