RESUMO
Heat stress negatively affects livestock, with undesirable effects on animals' production and reproduction. Temperature and humidity index (THI) is a climatic variable used worldwide to study the effect of heat stress on farm animals. Temperature and humidity data can be obtained in Brazil through the National Institute of Meteorology (INMET), but complete data may not be available due to temporary failures on weather stations. An alternative to obtaining meteorological data is the National Aeronautics and Space Administration Prediction of Worldwide Energy Resources (NASA POWER) satellite-based weather system. We aimed to compare THI estimates obtained from INMET weather stations and NASA POWER meteorological information sources using Pearson correlation and linear regression. After quality check, data from 489 INMET weather stations were used. The hourly, average daily and maximum daily THI were evaluated. We found greater correlations and better regression evaluation metrics when average daily THI values were considered, followed by maximum daily THI, and hourly THI. NASA POWER satellite-based weather system is a suitable tool for obtaining the average and maximum THI values using information collected from Brazil, showing high correlations with THI estimates from INMET and good regression evaluation metrics, and can assist studies that aim to analyze the impact of heat stress on livestock production in Brazil, providing additional data to complement the existing information available in the INMET database.
Assuntos
Transtornos de Estresse por Calor , Meteorologia , Animais , Estados Unidos , Feminino , Umidade , Temperatura , Brasil , United States National Aeronautics and Space Administration , Tempo (Meteorologia) , Transtornos de Estresse por Calor/veterinária , Temperatura Alta , Lactação , LeiteRESUMO
Individual variation in milk fatty acid (FA) composition has been partially attributed to stearoyl-CoA desaturase 1 (SCD1) gene polymorphisms in taurine breeds, but much less is known for Zebu breeds. This study investigated the phenotypic variation in milk FA composition, and the influence of SCD1 variants on this trait and on milk fat desaturase indices (DI) in Gir cows. The functional impact of SCD1 variants was predicted using bioinformatics tools. Milk and blood samples were collected from 312 cows distributed in 10 herds from five states of Brazil. SCD1 variants were identified through target sequencing, and milk FA composition was determined by gas chromatography. Phenotypic variation in milk FA composition fell within the range reported for taurine breeds, with SCD18 index showing the lowest variation among the DI. Fourteen SCD1 variants were identified, six of which not previously described. Regarding the A293V polymorphism, all cows were homozygous for the C allele (coding for alanine), whereas all genotypes were detected for the second SNP affecting the 293 codon (G > A), with compelling evidence for functional effects. Significant associations (based on raw p-values) were found between this SNP and C12:0, cis-9, trans-11 CLA and short-chain FA, and between another SNP (rs523411937) and C15:0 and odd-chain linear FA. A new SNP on Chr26:21277069 was associated with trans-11 C18:1, cis-9, trans-11 CLA, C18:3 n-3 and n-3 FA. These findings indicate that SCD1 polymorphisms also contributes to the phenotypic variation in milk FA composition of Gir cows, with potential use in their breeding programmes.
Assuntos
Ácidos Graxos , Leite , Feminino , Bovinos/genética , Animais , Estearoil-CoA Dessaturase/genética , Polimorfismo Genético , Variação Biológica da PopulaçãoRESUMO
This study aimed to investigate the feasibility of genomic prediction for productive and reproductive traits in Guzerá cattle using single-step genomic best linear unbiased prediction (ssGBLUP). Evaluations included the 305-day cumulative yields (first lactation, in kg) of milk, lactose, protein, fat, and total solids; adjusted body weight (kg) at the ages of 450, 365, and 210 days; and age at first calving (in days), from a database containing 197,283 measurements from Guzerá males and females born between 1954 and 2018. The pedigree included 433,823 animals spanning up to 14 overlapping generations. A total of 1618 animals were genotyped. The analyses were performed using ssGBLUP and traditional BLUP methods. Predictive ability and bias were accessed using cross-validation: predictive ability was similar between the methods and ranged from 0.27 to 0.47 for the genomic-based model and from 0.30 to 0.45 for the pedigree-based model; the bias was also similar between the methods, ranging from 0.88 to 1.35 in the genomic-based model and from 0.96 to 1.41 in the pedigree-based model. The individual accuracies of breeding values were evidently increased in the genomic evaluation, with values ranging from 0.41 to 0.56 in the genomic-based model and from 0.26 to 0.54 in the pedigree-based model. Even based on a small number of genotyped animals and a small database for some traits, the results suggest that ssGBLUP is feasible and may be applied to national genetic evaluation of the breed to increase the accuracy of breeding values without greatly impacting predictive ability and bias.
Assuntos
Genoma , Modelos Genéticos , Masculino , Feminino , Bovinos/genética , Animais , Brasil , Genômica/métodos , Fenótipo , Genótipo , LinhagemRESUMO
Genetic and omics analyses frequently require independent observations, which is not guaranteed in real datasets. When relatedness cannot be accounted for, solutions involve removing related individuals (or observations) and, consequently, a reduction of available data. We developed a network-based relatedness-pruning method that minimizes dataset reduction while removing unwanted relationships in a dataset. It uses node degree centrality metric to identify highly connected nodes (or individuals) and implements heuristics that approximate the minimal reduction of a dataset to allow its application to complex datasets. When compared with two other popular population genetics methodologies (PLINK and KING), NAToRA shows the best combination of removing all relatives while keeping the largest possible number of individuals in all datasets tested and also, with similar effects on the allele frequency spectrum and Principal Component Analysis than PLINK and KING. NAToRA is freely available, both as a standalone tool that can be easily incorporated as part of a pipeline, and as a graphical web tool that allows visualization of the relatedness networks. NAToRA also accepts a variety of relationship metrics as input, which facilitates its use. We also release a genealogies simulator software used for different tests performed in this study.
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OBJECTIVE: The aim of this study was to estimate genetic parameters for 305-day cumulative milk yield and components, growth, and reproductive traits in Guzerá cattle. METHODS: The evaluated traits were 305-day first-lactation cumulative yields (kg) of milk (MY305), fat (FY305), protein (PY305), lactose (LY305), and total solids (SY305); age at first calving (AFC) in days; adjusted scrotal perimeter (cm) at the ages of 365 (SP365) and 450 (SP450) days; and adjusted body weight (kg) at the ages of 210 (W210), 365 (W365), and 450 (W450) days. The (co)variance components were estimated using the restricted maximum likelihood method for single-trait, bi-trait and tri-trait analyses. Contemporary groups and additive genetic effects were included in the general mixed model. Maternal genetic and permanent environmental effects were also included for W210. RESULTS: The direct heritability estimates ranged from 0.16 (W210) to 0.32 (MY305). The maternal heritability estimate for W210 was 0.03. Genetic correlation estimates among milk production traits and growth traits ranged from 0.92 to 0.99 and from 0.92 to 0.99, respectively. For milk production and growth traits, the genetic correlations ranged from 0.33 to 0.56. The genetic correlations among AFC and all other traits were negative (-0.43 to -0.27). Scrotal perimeter traits and body weights showed genetic correlations ranging from 0.41 to 0.46, and scrotal perimeter and milk production traits showed genetic correlations ranging from 0.11 to 0.30. The phenotypic correlations were similar in direction (same sign) and lower than the corresponding genetic correlations. CONCLUSION: These results suggest the viability and potential of joint selection for dairy and beef traits in Guzerá cattle, taking into account reproductive traits.
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Whole genome sequencing of bovine breeds has allowed identification of genetic variants in milk protein genes. However, functional repercussion of such variants at a molecular level has seldom been investigated. Here, the results of a multistep Bioinformatic analysis for functional characterization of recently identified genetic variants in Brazilian Gyr and Guzerat breeds is described, including predicted effects on the following: (i) evolutionary conserved nucleotide positions/regions; (ii) protein function, stability, and interactions; (iii) splicing, branching, and miRNA binding sites; (iv) promoters and transcription factor binding sites; and (v) collocation with QTL. Seventy-one genetic variants were identified in the caseins (CSN1S1, CSN2, CSN1S2, and CSN3), LALBA, LGB, and LTF genes. Eleven potentially regulatory variants and two missense mutations were identified. LALBA Ile60Val was predicted to affect protein stability and flexibility, by reducing the number the disulfide bonds established. LTF Thr546Asn is predicted to generate steric clashes, which could mildly affect iron coordination. In addition, LALBA Ile60Val and LTF Thr546Asn affect exonic splicing enhancers and silencers. Consequently, both mutations have the potential of affecting immune response at individual level, not only in the mammary gland. Although laborious, this multistep procedure for classifying variants allowed the identification of potentially functional variants for milk protein genes.
Assuntos
Caseínas , Proteínas do Leite , Animais , Bovinos/genética , Simulação por Computador , Mutação , Regiões Promotoras GenéticasRESUMO
This study aimed to estimate the genetic parameters for somatic cell count (SCC) and the genetic association between SCC and milk production traits using two different methods of SCC normalization. The dataset contained information on 8870 lactation records of 6172 Guzerá dairy cows selected for dual-purpose from 95 herds. The lactation means of SCC were normalized in two ways: (a) SCC1 = log10 (SCC) and (b) SCC2 = log2 (SCC/100) + 3. Multivariate analyses were performed considering milk production traits over the course of 305 days of lactation. Estimates of the variance components and genetic parameters were carried out by the Bayesian inference method, applying Gibbs sampling. Single chains of 2,000,000 iterations were used, with sampling discards of the first 5000 chains and a sampling period of every 50 iterations. The deviation of information criteria (DIC) was used to evaluate the best transformation for standardization of the SCC data, comparing analysis 1 (milk production traits over 305 days and SCC1) with analysis 2 (milk production traits over 305 days and SCC2). According to the data structure of this study, SCC1 normalization was the most efficient method and produced better estimates than normalization by the SCC2 method. The heritability estimates for SCC were low regardless of the transformation method used, indicating a small possibility of expressive genetic gains from the direct selection of these traits. However, the repeatability indicated the potential for increasing heritability estimates if the effects of the permanent environment were reduced. The genetic correlations between the milk yield and SCC traits do not indicate the possibility of a correlated genetic gain from the direct selection of one trait. However, concomitant selection for milk production traits and SCC will likely not affect the individual response either.
Assuntos
Bovinos/genética , Bovinos/fisiologia , Lactação/fisiologia , Leite/citologia , Animais , Teorema de Bayes , Contagem de Células/veterinária , FemininoRESUMO
This study aimed to estimate the genetic parameters of milk (305-day milk yield (MY305)), growth (weaning weight (WW), yearling weight (YW), and weight at 550 days (W550)), and reproductive (age at first calving (AFC)) traits in Guzerá cattle by using Bayesian multiple-trait models. Systematic effects included sex and age at calving for the growth and milk traits, respectively. The additive genetic and contemporary groups (herd and year and season of birth) were included as random effects. Additionally, maternal genetic and permanent effects were also included as random effects for the WW. The heritability estimates were 0.29 (MY305), 0.42 (WW), 0.49 (YW), 0.56 (W550), and 0.25 (AFC). The genetic correlations among the growth traits were higher than 0.83; between the MY305 and WW, MY305 and YW, and MY305 and W550, the genetic correlations were 0.25, 0.32, and 0.36, respectively. The AFC was negatively correlated with the milk and growth traits. These results suggest the viability and potential of the joint selection for milk, beef, and reproductive traits in Guzerá cattle.
Assuntos
Bovinos/fisiologia , Leite/metabolismo , Reprodução/genética , Fatores Etários , Animais , Teorema de Bayes , Peso Corporal/genética , Bovinos/genética , Bovinos/crescimento & desenvolvimento , Feminino , Masculino , Modelos Genéticos , Clima Tropical , DesmameRESUMO
This work was realized to evaluate lactation stage, physiological state, somatic cell count (SCC) and body condition score (BCS) on production and composition of cow's milk from Gir and Guzerat breeds were studied. Ninety-eight cows were analyzed and classified according to their physiological state, lactation stage, SCC and BCS. Milk production was weighed monthly to obtain production data. Composed samples were collected in vials containing preservatives and sent to the laboratory for analysis. Data were used for statistic descriptive analysis and analysis of variance. Higher milk production in the first 60 days of lactation was observed. Fat, protein and total solids concentration increased according to the increase of days in milk; while lactose concentration decreased. Higher levels of fat, protein and total solids in milk of non-pregnant cows were observed; while pregnant cows had higher daily production and higher lactose content in their milk. Higher lactose levels in milk were observed in animals with lower SCC. The BCS had no effect on milk composition or on somatic cell count. Zebu cow milk production and composition are influenced by lactation stage, physiological state and SCC.(AU)
Neste trabalho, objetivou-se avaliar o efeito do estádio de lactação, estado fisiológico, contagem de células somáticas (CCS) e escore de condição corporal (ECC) sobre a produção e composição do leite de vacas Gir e Guzerá. Foram utilizadas noventa e oito vacas, que foram classificadas de acordo com o estado fisiológico, estádio de lactação, CCS e ECC. O leite foi pesado mensalmente para obtenção dos dados de produção. Amostras compostas coletadas em frascos contendo conservante foram enviadas ao laboratório para análises. Os dados foram submetidos a análises estatísticas descritivas e de variâncias. Verificou-se maior produção de leite nos primeiros 60 dias de lactação. Os teores de gordura, proteína e extrato seco aumentaram com o avançar da lactação; enquanto o teor de lactose decresceu. Foram observados maiores teores de gordura, proteína e sólidos totais no leite de vacas vazias; enquanto as vacas gestantes apresentaram maior produção diária e maior teor de lactose no leite. Maiores teores de lactose foram verificados em animais com menor CCS. O ECC não teve efeito sobre a composição e escore de células somáticas do leite. A produção e composição do leite de vacas zebuínas sofrem influência do estádio de lactação, do estado fisiológico e da CCS.(AU)
Assuntos
Animais , Feminino , Bovinos , Substitutos do Leite Humano , Leite , Animais Lactentes , BovinosRESUMO
Milk production has high economic importance in dairy cattle production systems, which justifies its inclusion in genetic breeding programs. The objective of this study was to evaluate the genetic and phenotypic trends of dairy traits in Gyr (167 lactations) and Guzerá (148 lactations) breeds in the State of Rio Grande do Norte (RN). Milk, fat and protein production obtained from monthly dairy controls were the traits evaluated. The expected differences in progeny (DEPs) for these traits were estimated using an animal model. From the means of phenotypic values and DEPs, we estimated the genetic and phenotypic trends in linear regressions as a function of the year of calving of the animal. Positive genetic and phenotypic trends were observed for Gyr (26.8 and 88.7 kg year-1) and Guzerá (8.44 and 37.68 kg year-1). Gyr breed presented positive genetic trends for fat (1.08 kg year-1) and protein (0.45 kg year-1) production and the Guzerá breed showed positive genetic trends for fat (0.36 kg year-1) and protein (0.25 kg year-1) production. The selection applied in the evaluated herds has produced satisfactory genetic and phenotypic progress for milk, fat and protein production.(AU)
A produção de leite tem elevada importância econômica em sistemas de produção de bovinos leiteiros, sendo, portanto, justificada a sua inclusão em programas de melhoramento genético. Objetivou-se avaliar as tendências genética e fenotípica de características leiteiras em animais das raças Gir (167 lactações) e Guzerá (148 lactações) no Estado do Rio Grande do Norte (RN). As características avaliadas foram produção de leite, gordura e proteína, obtida a partir de controles leiteiros mensais. As diferenças esperadas na progênie (DEPs) para estas características foram preditas utilizando-se um modelo animal. Pelas médias dos valores fenotípicos e das DEPs foram estimadas as tendências fenotípicas e genéticas em regressões lineares, em função dos anos de nascimento dos animais. Foram observadas tendências genéticas e fenotípicas positivas para a produção de leite da raça Gir (26,8 e 88,7 kg ano-1) e Guzerá (8,44 e 37,68 kg ano-1). A raça Gir apresentou tendências genéticas positivas para a produção de gordura (1,08 kg ano-1) e proteína (0,45 kg ano-1) e a raça Guzerá apresentou tendências genéticas positivas para produção de gordura (0,36 kg ano-1) e proteína (0,25 kg ano-1). A seleção aplicada nos rebanhos avaliados tem produzido progressos genéticos e fenotípicos satisfatórios para as características leiteiras produção de leite, gordura e proteína.(AU)
Assuntos
Animais , Feminino , Lactente , Bovinos , Bovinos/genética , Bovinos/metabolismo , Leite/química , Leite/classificação , Melhoramento GenéticoRESUMO
Milk production has high economic importance in dairy cattle production systems, which justifies its inclusion in genetic breeding programs. The objective of this study was to evaluate the genetic and phenotypic trends of dairy traits in Gyr (167 lactations) and Guzerá (148 lactations) breeds in the State of Rio Grande do Norte (RN). Milk, fat and protein production obtained from monthly dairy controls were the traits evaluated. The expected differences in progeny (DEPs) for these traits were estimated using an animal model. From the means of phenotypic values and DEPs, we estimated the genetic and phenotypic trends in linear regressions as a function of the year of calving of the animal. Positive genetic and phenotypic trends were observed for Gyr (26.8 and 88.7 kg year-1) and Guzerá (8.44 and 37.68 kg year-1). Gyr breed presented positive genetic trends for fat (1.08 kg year-1) and protein (0.45 kg year-1) production and the Guzerá breed showed positive genetic trends for fat (0.36 kg year-1) and protein (0.25 kg year-1) production. The selection applied in the evaluated herds has produced satisfactory genetic and phenotypic progress for milk, fat and protein production.
A produção de leite tem elevada importância econômica em sistemas de produção de bovinos leiteiros, sendo, portanto, justificada a sua inclusão em programas de melhoramento genético. Objetivou-se avaliar as tendências genética e fenotípica de características leiteiras em animais das raças Gir (167 lactações) e Guzerá (148 lactações) no Estado do Rio Grande do Norte (RN). As características avaliadas foram produção de leite, gordura e proteína, obtida a partir de controles leiteiros mensais. As diferenças esperadas na progênie (DEPs) para estas características foram preditas utilizando-se um modelo animal. Pelas médias dos valores fenotípicos e das DEPs foram estimadas as tendências fenotípicas e genéticas em regressões lineares, em função dos anos de nascimento dos animais. Foram observadas tendências genéticas e fenotípicas positivas para a produção de leite da raça Gir (26,8 e 88,7 kg ano-1) e Guzerá (8,44 e 37,68 kg ano-1). A raça Gir apresentou tendências genéticas positivas para a produção de gordura (1,08 kg ano-1) e proteína (0,45 kg ano-1) e a raça Guzerá apresentou tendências genéticas positivas para produção de gordura (0,36 kg ano-1) e proteína (0,25 kg ano-1). A seleção aplicada nos rebanhos avaliados tem produzido progressos genéticos e fenotípicos satisfatórios para as características leiteiras produção de leite, gordura e proteína.
Assuntos
Feminino , Animais , Lactente , Bovinos , Bovinos/genética , Bovinos/metabolismo , Leite/classificação , Leite/química , Melhoramento GenéticoRESUMO
This work was realized to evaluate lactation stage, physiological state, somatic cell count (SCC) and body condition score (BCS) on production and composition of cow's milk from Gir and Guzerat breeds were studied. Ninety-eight cows were analyzed and classified according to their physiological state, lactation stage, SCC and BCS. Milk production was weighed monthly to obtain production data. Composed samples were collected in vials containing preservatives and sent to the laboratory for analysis. Data were used for statistic descriptive analysis and analysis of variance. Higher milk production in the first 60 days of lactation was observed. Fat, protein and total solids concentration increased according to the increase of days in milk; while lactose concentration decreased. Higher levels of fat, protein and total solids in milk of non-pregnant cows were observed; while pregnant cows had higher daily production and higher lactose content in their milk. Higher lactose levels in milk were observed in animals with lower SCC. The BCS had no effect on milk composition or on somatic cell count. Zebu cow milk production and composition are influenced by lactation stage, physiological state and SCC.
Neste trabalho, objetivou-se avaliar o efeito do estádio de lactação, estado fisiológico, contagem de células somáticas (CCS) e escore de condição corporal (ECC) sobre a produção e composição do leite de vacas Gir e Guzerá. Foram utilizadas noventa e oito vacas, que foram classificadas de acordo com o estado fisiológico, estádio de lactação, CCS e ECC. O leite foi pesado mensalmente para obtenção dos dados de produção. Amostras compostas coletadas em frascos contendo conservante foram enviadas ao laboratório para análises. Os dados foram submetidos a análises estatísticas descritivas e de variâncias. Verificou-se maior produção de leite nos primeiros 60 dias de lactação. Os teores de gordura, proteína e extrato seco aumentaram com o avançar da lactação; enquanto o teor de lactose decresceu. Foram observados maiores teores de gordura, proteína e sólidos totais no leite de vacas vazias; enquanto as vacas gestantes apresentaram maior produção diária e maior teor de lactose no leite. Maiores teores de lactose foram verificados em animais com menor CCS. O ECC não teve efeito sobre a composição e escore de células somáticas do leite. A produção e composição do leite de vacas zebuínas sofrem influência do estádio de lactação, do estado fisiológico e da CCS.
Assuntos
Feminino , Animais , Bovinos , Animais Lactentes , Leite , Substitutos do Leite Humano , BovinosRESUMO
Temperament is fundamental to animal production due to its direct influence on the animal-herdsman relationship. When compared to calm animals, the aggressive, anxious or fearful ones exhibit less weight gain, lower reproductive efficiency, decreased milk production and higher herd maintenance costs, all of which contribute to reduced profits. However, temperament is a trait that is complex and difficult to assess. Recently, a new quantitative system, REATEST®, for assessing reactivity, a phenotype of temperament, was developed. Herein, we describe the results of a Genome-wide association study for reactivity, assessed using REATEST® with a sample of 754 females from five dual-purpose (milk and meat production) Guzerat (Bos indicus) herds. Genotyping was performed using a 50k SNP chip and a two-step mixed model approach (Grammar-Gamma) with a one-by-one marker regression was used to identify QTLs. QTLs for reactivity were identified on chromosomes BTA1, BTA5, BTA14, and BTA25. Five intronic and two intergenic markers were significantly associated with reactivity. POU1F1, DRD3, VWA3A, ZBTB20, EPHA6, SNRPF and NTN4 were identified as candidate genes. Previous QTL reports for temperament traits, covering areas surrounding the SNPs/genes identified here, further corroborate these associations. The seven genes identified in the present study explain 20.5% of reactivity variance and give a better understanding of temperament biology.
Assuntos
Estudo de Associação Genômica Ampla , Genótipo , Locos de Características Quantitativas , Característica Quantitativa Herdável , Temperamento , Animais , Cruzamento , Bovinos , Mapeamento Cromossômico , Cromossomos de Mamíferos/química , Epistasia Genética , Feminino , Interação Gene-Ambiente , Marcadores Genéticos , FenótipoRESUMO
ABSTRACT: The aim of this study was to explore the pattern of genetic lactation curves of Guzerá cattle using cluster analysis. Test-day milk yields of 5,274 first-lactation Guzerá cows were recorded in a progeny test. A total of 34,193 monthly records were analyzed with a random regression animal model using Legendre polynomials to fit additive genetic and permanent environmental random effects and mean trends. Hierarchical and non-hierarchical cluster analyses were performed based on the EBVs for monthly test-day milk yield, peak yield, lactation persistency, and partial cumulative and 305-day yields. The heritability estimates for test-day milk yields ranged from 0.24 to 0.52. Cluster analysis identified animals in the population that belong to different groups according to milk production level and lactation persistency.
RESUMO: Objetivou-se neste estudo explorar o padrão das curvas de lactação genéticas de bovinos da raça Guzerá, empregando análises de agrupamento. Os 34.193 registros mensais de produção de leite foram provenientes de 5.274 vacas da raça Guzerá, participantes do teste de progênie. As análises foram realizadas com um modelo de regressão aleatória com polinômios de Legendre, composto pelos efeitos aleatórios genético aditivo, de ambiente permanente e o residual, e a curva média de lactação da população. Análise de agrupamento hierárquico e não hierárquico foram realizados com base nos VG para a produção acumulada até os 305 dias, pico e persistência da lactação, e períodos parciais da lactação. As estimativas de herdabilidade para produção de leite no dia do controle variaram entre 0,24 a 0,52. A análise de agrupamento identificou os animais da população que pertencem a diferentes grupos de acordo com o nível de produção de leite e persistência da lactação.
RESUMO
The aim of this study was to explore the pattern of genetic lactation curves of Guzerá cattle using cluster analysis. Test-day milk yields of 5,274 first-lactation Guzerá cows were recorded in a progeny test. A total of 34,193 monthly records were analyzed with a random regression animal model using Legendre polynomials to fit additive genetic and permanent environmental random effects and mean trends. Hierarchical and non-hierarchical cluster analyses were performed based on the EBVs for monthly test-day milk yield, peak yield, lactation persistency, and partial cumulative and 305-day yields. The heritability estimates for test-day milk yields ranged from 0.24 to 0.52. Cluster analysis identified animals in the population that belong to different groups according to milk production level and lactation persistency.(AU)
Objetivou-se neste estudo explorar o padrão das curvas de lactação genéticas de bovinos da raça Guzerá, empregando análises de agrupamento. Os 34.193 registros mensais de produção de leite foram provenientes de 5.274 vacas da raça Guzerá, participantes do teste de progênie. As análises foram realizadas com um modelo de regressão aleatória com polinômios de Legendre, composto pelos efeitos aleatórios genético aditivo, de ambiente permanente e o residual, e a curva média de lactação da população. Análise de agrupamento hierárquico e não hierárquico foram realizados com base nos VG para a produção acumulada até os 305 dias, pico e persistência da lactação, e períodos parciais da lactação. As estimativas de herdabilidade para produção de leite no dia do controle variaram entre 0,24 a 0,52. A análise de agrupamento identificou os animais da população que pertencem a diferentes grupos de acordo com o nível de produção de leite e persistência da lactação.(AU)
Assuntos
Animais , Feminino , Lactente , Bovinos , Lactação/genética , Indústria de Laticínios/estatística & dados numéricos , Análise de RegressãoRESUMO
Diacylglycerol-O-acyltransferase (DGAT1) gene encodes the rate-limiting enzyme of triglyceride synthesis. A polymorphism in this gene, DGAT1 K232A, has been associated with milk production and composition in taurine breeds. However, this polymorphism is not a good tool for ascertaining the effects of this QTL in Bos indicus (Zebu), since the frequency of the DGAT1 232A allele is too low in these breeds. We sequenced the 3'-untranslated region of DGAT1 gene in a sample of bulls of the breeds Guzerá (Bos indicus) and Holstein (Bos taurus) and, using in silico analysis, we searched for genetic variation, evolutionary conservation, regulatory elements, and possible substitution effects. Six single nucleotide (SNPs) and one insertion-deletion (INDEL) polymorphisms were found in the Guzerá bulls. Additionally, we developed a preliminary association study, using this INDEL polymorphism as a genetic marker. A significant association was detected (P ≤ 0.05) between the INDEL (DGAT1 3'UTR INDEL) and the breeding values (BV) for protein, fat, and milk yields over a 305-day lactation period. The DGAT1 3' UTR INDEL genotype I/I (I, for insertion) was associated with lower BVs (-38.77 kg for milk, -1.86 kg for fat, and -1.48 kg for protein yields), when compared to the genotype I/D (D, for deletion). I/D genotype was lower D/D genotype (-34.98 kg milk, -1.73 kg fat, and -1.09 kg protein yields). This study reports the first polymorphism of DGAT1 3'UTR in the Guzerá breed, as well as its association with BV for milk protein, fat, and milk yields.
Assuntos
Regiões 3' não Traduzidas , Diacilglicerol O-Aciltransferase/genética , Mutação INDEL , Lactação/genética , Polimorfismo de Nucleotídeo Único , Característica Quantitativa Herdável , Animais , Cruzamento , Bovinos , Simulação por Computador , Diacilglicerol O-Aciltransferase/metabolismo , Feminino , Expressão Gênica , Genótipo , Glicolipídeos/biossíntese , Glicolipídeos/genética , Glicoproteínas/biossíntese , Glicoproteínas/genética , Gotículas Lipídicas , Masculino , Leite/química , Proteínas do Leite/biossíntese , Proteínas do Leite/genética , Modelos GenéticosRESUMO
Foram analisados 13.406 registros de lactação de 7.153 vacas Gir Leiteiro com partos ocorridos de 1960 a 2008 com o objetivo de estimar ganhos ou perdas econômicas e em produção de leite atribuídos à variação no intervalo de partos (IP). Foi observada produção de leite média por vaca por lactação de 2.846,95 ± 1.339,72 kg e média de IP de 449,86 ± 51,54 dias. A redução do IP observado para 365 dias levaria a aumento na produção de leite de 558,16 kg. Os resultados econômicos decorrentes das perdas nas produções de leite e de bezerros foram de R$ 467,34/vaca/ lactação. Os gastos com ração e mão de obra foram de R$ 198,22. A perda econômica total foi de R$ 269,12/vaca/lactação. O aumento no IP tem resultado em perdas produtivas e econômicas nos rebanhos estudados.(AU)
f 13,406 records from 7,153 lactating Gyr dairy cows whose calving occurred from 1960 to 2008 were used. The purpose of this study was to estimate gains or losses in milk production and economic values attributed to the variation in the calving interval (IP). The average of milk production and IP were 2,846.95 ± 1,339.72 kg and 449.86 ± 51.54 days per cow per lactation, respectively. The reduction of IP to 365 days would increase milk production approximately 558.16 kg. The economic losses in produced milk yield and calves were R$ 467.34/cow/lactation. The expenses with labor and concentrate were R$ 198.22. The total economic loss was R$ 269.12/cow/ lactation. The increase in IP has resulted in productive and economic losses in studied herds.(AU)
Assuntos
Animais , Período Pós-Parto/fisiologia , Eficiência , Economia , Bovinos/classificaçãoRESUMO
Foram analisados 13.406 registros de lactação de 7.153 vacas Gir Leiteiro com partos ocorridos de 1960 a 2008 com o objetivo de estimar ganhos ou perdas econômicas e em produção de leite atribuídos à variação no intervalo de partos (IP). Foi observada produção de leite média por vaca por lactação de 2.846,95 ± 1.339,72 kg e média de IP de 449,86 ± 51,54 dias. A redução do IP observado para 365 dias levaria a aumento na produção de leite de 558,16 kg. Os resultados econômicos decorrentes das perdas nas produções de leite e de bezerros foram de R$ 467,34/vaca/ lactação. Os gastos com ração e mão de obra foram de R$ 198,22. A perda econômica total foi de R$ 269,12/vaca/lactação. O aumento no IP tem resultado em perdas produtivas e econômicas nos rebanhos estudados.
f 13,406 records from 7,153 lactating Gyr dairy cows whose calving occurred from 1960 to 2008 were used. The purpose of this study was to estimate gains or losses in milk production and economic values attributed to the variation in the calving interval (IP). The average of milk production and IP were 2,846.95 ± 1,339.72 kg and 449.86 ± 51.54 days per cow per lactation, respectively. The reduction of IP to 365 days would increase milk production approximately 558.16 kg. The economic losses in produced milk yield and calves were R$ 467.34/cow/lactation. The expenses with labor and concentrate were R$ 198.22. The total economic loss was R$ 269.12/cow/ lactation. The increase in IP has resulted in productive and economic losses in studied herds.