Factor Analysis of Linear Type Traits and Their Relation with Longevity in Brazilian Holstein Cattle

In this study we aimed to evaluate the reduction in dimensionality of 20 linear type traits and more final score in 14,943 Holstein cows in Brazil using factor analysis, and indicate their relationship with longevity and 305 d first lactation milk production. Low partial correlations (−0.19 to 0.38), the medium to high Kaiser sampling mean (0.79) and the significance of the Bartlett sphericity test (p<0.001), indicated correlations between type traits and the suitability of these data for a factor analysis, after the elimination of seven traits. Two factors had autovalues greater than one. The first included width and height of posterior udder, udder texture, udder cleft, loin strength, bone quality and final score. The second included stature, top line, chest width, body depth, fore udder attachment, angularity and final score. The linear regression of the factors on several measures of longevity and 305 d milk production showed that selection considering only the first factor should lead to improvements in longevity and 305 milk production

Genetic association between longevity and linear type traits of Holstein cows

Longevity is a desirable trait in the dairy industry because of its relationship to profitability. The aim of this study was to estimate genetic parameters for longevity measurements related to productive life, or life in the herd, and linear type traits of Brazilian Holstein cows born between the years 1990 and 2008. The (co) variance components were estimated by the restricted maximum likelihood method. The heritability for measurements of longevity and linear type traits ranged from 0.05 to 0.07 and 0.08 to 0.39, respectively. The genetic correlations between measurements of longevity and linear type traits ranged from -0.39 to 0.31. Direct selection for longevity does not necessarily lead to long-lived cows, due to low heritability. Indirect genetic selection for udder depth, bone quality, udder height, rear teat placement and conformation traits showed the highest genetic correlations with measurements of time between birth and last milk record and time from first calving to last milk record

Genetic association between longevity and linear type traits of Holstein cows

Longevity is a desirable trait in the dairy industry because of its relationship to profitability. The aim of this study was to estimate genetic parameters for longevity measurements related to productive life, or life in the herd, and linear type traits of Brazilian Holstein cows born between the years 1990 and 2008. The (co) variance components were estimated by the restricted maximum likelihood method. The heritability for measurements of longevity and linear type traits ranged from 0.05 to 0.07 and 0.08 to 0.39, respectively. The genetic correlations between measurements of longevity and linear type traits ranged from -0.39 to 0.31. Direct selection for longevity does not necessarily lead to long-lived cows, due to low heritability. Indirect genetic selection for udder depth, bone quality, udder height, rear teat placement and conformation traits showed the highest genetic correlations with measurements of time between birth and last milk record and time from first calving to last milk record

Random Regression Models Are Suitable to Substitute the Traditional 305-Day Lactation Model in Genetic Evaluations of Holstein Cattle in Brazil

The aim of this study was to compare two random regression models (RRM) fitted by fourth (RRM4) and fifth-order Legendre polynomials (RRM5) with a lactation model (LM) for evaluating Holstein cattle in Brazil. Two datasets with the same animals were prepared for this study. To apply test-day RRM and LMs, 262,426 test day records and 30,228 lactation records covering 305 days were prepared, respectively. The lowest values of Akaike’s information criterion, Bayesian information criterion, and estimates of the maximum of the likelihood function (−2LogL) were for RRM4. Heritability for 305-day milk yield (305MY) was 0.23 (RRM4), 0.24 (RRM5), and 0.21 (LM). Heritability, additive genetic and permanent environmental variances of test days on days in milk was from 0.16 to 0.27, from 3.76 to 6.88 and from 11.12 to 20.21, respectively. Additive genetic correlations between test days ranged from 0.20 to 0.99. Permanent environmental correlations between test days were between 0.07 and 0.99. Standard deviations of average estimated breeding values (EBVs) for 305MY from RRM4 and RRM5 were from 11% to 30% higher for bulls and around 28% higher for cows than that in LM. Rank correlations between RRM EBVs and LM EBVs were between 0.86 to 0.96 for bulls and 0.80 to 0.87 for cows. Average percentage of gain in reliability of EBVs for 305-day yield increased from 4% to 17% for bulls and from 23% to 24% for cows when reliability of EBVs from RRM models was compared to those from LM model. Random regression model fitted by fourth order Legendre polynomials is recommended for genetic evaluations of Brazilian Holstein cattle because of the higher reliability in the estimation of breeding values

Phenotypic relationships between type traits and productive life using a piecewise Weibull proportional hazard model

ABSTRACT: Longevity is an important trait due to its relationship with profitability. Type traits have been used as indirect predictors for productive life. The objective of this study was to evaluate the relationship of 20 type traits on length of productive life in Brazilian Holsteins, using a piecewise Weibull proportional hazard model. Three analyses were performed i) productive life was corrected for within herd level of production as a proxy for functional longevity, which included the time-dependent effects of region within year, class of milk production within herdyear, milk production class within lactation number, fat class and protein contents within herd and (variation in) herd size as well as the time-independent fixed effect of age at first calving and the type trait score; ii) the effects related to production were omitted from the first model (true longevity) and iii) with the first model, the effect of type was also studied considering five classes of percentage of type-scored cows within the herd. All analyses were performed using the Survival Kit program. The final score, angularity, top line, udder texture and suspensory ligament showed the strongest relationship with productive life. When type traits were available only for a small fraction of the herd, the cows had a better chance of remaining longer in the herd. The absence of type trait phenotypes was associated with a strong increase of culling risk for the cows. Type traits were not found to be good indirect predictors of productive life in Brazil

Phenotypic relationships between type traits and productive life using a piecewise Weibull proportional hazard model

Longevity is an important trait due to its relationship with profitability. Type traits have been used as indirect predictors for productive life. The objective of this study was to evaluate the relationship of 20 type traits on length of productive life in Brazilian Holsteins, using a piecewise Weibull proportional hazard model. Three analyses were performed i) productive life was corrected for within herd level of production as a proxy for functional longevity, which included the time-dependent effects of region within year, class of milk production within herdyear, milk production class within lactation number, fat class and protein contents within herd and (variation in) herd size as well as the time-independent fixed effect of age at first calving and the type trait score; ii) the effects related to production were omitted from the first model (true longevity) and iii) with the first model, the effect of type was also studied considering five classes of percentage of type-scored cows within the herd. All analyses were performed using the Survival Kit program. The final score, angularity, top line, udder texture and suspensory ligament showed the strongest relationship with productive life. When type traits were available only for a small fraction of the herd, the cows had a better chance of remaining longer in the herd. The absence of type trait phenotypes was associated with a strong increase of culling risk for the cows. Type traits were not found to be good indirect predictors of productive life in Brazil

Formation of base populations of meat-type chickens. III. Evaluation of male line from reproductive traits

O presente trabalho foi conduzido no Centro Nacional de Pesquisa de Suínos e Aves (CNPSA), utilizando-se machos e fêmeas da linha macho de matrizes para corte. As aves foram provenientes de um cruzamento dialélico completo entre quatro linhagens comer­ciais, denominadas, simbolicamente, L1, L2, L3 e L4. Os números de l a 4 identificam as diferentes origens. Efetuou-se a avaliação dos cruzamentos quanto às características volume de sêmen, fertilidade, eclodibilidade e nascimento. Não foram observadas diferenças significati­vas entre os cruzamentos, para as características avaliadas. A capacidade específica de com­binação e efeitos recíprocos foram significativos para todas as características avaliadas, exceto eclodibilidade. O mesmo ocorreu para capacidade geral de combinação, à exceção da fertilidade. O efeito da heterose não foi significativo para as características avaliadas. No geral, os efeitos médios mais favoráveis foram: L3 para volume de sêmen e L1 para eclodibili­dade e nascimento.This study was carried out at the Centro Nacional de Pesquisa de Suínos e Aves (CNPSA) (National Swine and Poultry Research Center) of EMBRAPA, with the objective of testing four commercial strains of meat-type chickens using diallel crosses. There were four male lines, identified by L1, L2, L3 and L4. The characteristics semen volume, fertility, hatchability and birth rate were evaluated. There were no significant differences among crosses from traits evaluated. The specific combining ability and reciprocal effects were significant for all characteristics evaluated except hatchability. Also the effects of general combining ability were observed, except for fertility. The lines that present best results were: L3 for semen volume, L1 for hatchability, L3 for fertility, and birth rate

Interação genótipo-ambiente na produção de leite de vacas da raça Holandesa = Genotype-environment interaction on milk yield of Holstein cows

Os efeitos, sobre a avaliação genética da interação reprodutor-região, foram investigados analisando-se 108.702 registros de produção de leite (PL305) de vacas da raça Holandesa, pertencentes a rebanhos de Minas Gerais, São Paulo, Paraná, Sanata Catarina eRio Grande do Sul. Um modelo animal multicarácter foi aplicado para estimar os componentes de variância e covariância utilizando amostragem de Gibbs. As médias a posteriori da variância genética de Santa Catarina e Rio Grande do Sul foram superiores (p 0,05) entre si. As herdabilidades variaram entre 0,24 e 0,38. As correlações genéticas entre os Estados foram de baixa magnitude e variaram entre 0,07 a 0,33. Os valores de correlação de Spearman entre os valores genéticos dos reprodutores variaram entre 0,73 e 0,86. Os resultados sugerem aexistência da interação genótipo-ambiente para PL305 entre os Estados de Minas Gerais, São Paulo, Paraná e os Estados de Santa Catarina e Rio Grande do Sul.The effects of sire-environment interaction on genetic evaluation were investigated by analyzing 108,702 records of milk yield (305ME) of Holstein cows from the states of Minas Gerais, São Paulo, Paraná, Santa Catarina and Rio Grande do Sul. A Multivariate animal model was applied to estimate of genetic variance and covariance components, using Gibbs sampling. The a posteriori means of genetic variance in Santa Catarina and Rio Grande do Sul were higher (p 0.05) between these two states. Heritability estimates of states ranged from 0.24 to 0.38. Genetic correlations among states were low and ranged from 0.07 to 0.33. Spearman’s correlation among sire breeding values ranged from 0.73 to 0.86. These results suggest sire-environment interaction for 305ME in the states of Minas Gerais, São Paulo, Paraná and between the states of Santa Catarina and Rio Grande do Sul

Formation of base-populations of meat-type chickens using diallel crosses of commercial strains. II. Evaluation of the body weight

O presente trabalho foi desenvolvido no Centro Nacional de Pesquisa de Suínos e Aves (CNPSA), da EMBRAPA, com o objetivo de avaliar o comportamento de quatro li­nhagens comerciais para a produção de aves de corte, em cruzamentos dialélicos. Estas foram denominadas L1, L2, L3, L4, P1, P2, P3 e P4; as letras L e P identificam, respectivamente, as linhas produtoras de matrizes macho e fêmea, e os números de l a 4, as diferentes origens. Efetuou-se a análise do cruzamento dialélico entre linhagens, separadamente para as linhas de macho e fêmea, quanto ao peso corporal aos 42 dias. Foram observadas diferenças significa­tivas entre os cruzamentos, para a característica avaliada. Os efeitos da capacidade geral e es­pecífica de combinação e efeitos recíprocos foram significativos. As linhagens P2 (linha fê­mea) e L2 (linha macho) apresentaram efeitos médios mais favoráveis quanto ao peso corpo­ral aos 42 dias.This study was carried out at the Centro Nacional de Pesquisa de Suínos e Aves (National Swine and Poultry Research Center/EMBRAPA) with the objective of testing four commercial strains of meat-type chickens using diallel crosses. There were four male lines and four female lines, identified by L (L1, L2, L3 and L4) and P (P1, P2, P3 and P4), respectively. The analysis of diallel crosses among strains, within male and female lines was based on body weight at 42 days. There were significant differences among crosses on body weight and reciprocal effects, general and specific combining ability. The lines that showed best results for body weight at 42 days were P2 and L2

Formation of base populations of meat-type chickens. I. Evaluation of commercial strains

O presente trabalho foi desenvolvido no Centro Nacional de Pesquisa de Suínos e Aves (CNPSA), com o objetivo de avaliar o comportamento de quatro linhagens comerciais para a produção de aves para corte. Estas, foram denominadas, simbolicamente, de L1, L2, L3, L4, P1, P2, P3 e P4, onde as letras L e P identificam, respectivamente, as linhas produ­toras de matrizes macho e fêmea, e os números de 1 a 4 as diferentes origens do rebanho co­mercial. O material genético, utilizado posteriormente no cruzamento dialélico, foi compara­do com duas linhagens comerciais não utilizadas na formação das populações-bases, quanto às seguintes características: peso médio aos 28 e 49 dias, conversão alimentar até 28 e 49 dias e mortalidade até 49 dias. A avaliação preliminar das linhagens comerciais, utilizadas no pre­sente trabalho, quanto às características de crescimento, indicou que estas apresentaram re­sultados satisfatórios, com vistas à formação de populações-bases para as linhas de macho e fêmea através do cruzamento dialélico.This study was carried out at the National Swine and Poultry Research Center (CNPSA-EMBRAPA), in Brazil, with the objective of testing four commercial strains of meat-type chickens in a diallel cross in order to form a base population of meat-type chicken. There were four male lines and four female lines, identified by L (L1, L2, L3 e L4) and P (P1, P2, P3 e P4), respectively. The basic genetic material was evaluated in comparison to two commercial lines, not included in the crosses, according to the average weight at 28 days and 49 days of age, feed conversion from 1 to 28 days and from 1 to 49 days of age, and mortality rate from 1 to 49 days of age. The preliminar evaluation of commercial lines on the basis of growth characteristics of broiler, indicated satisfactory results to create the base populations of male and female lines through diallel crosses, male and female line, weight