Variants in GH, IGF1, and LEP genes associated with body traits in Santa Inês sheep

Growth hormone (GH), insulin-like growth factor 1 (IGF1), and leptin (LEP) can be candidate genes for association studies because they play vital roles in the metabolism process. Thus, this study aimed to identify variants in these genes associated with body traits in Santa Inês sheep. The following were recorded: body weight at 100 (BW100) and 240 days (BW240), average daily gain (ADG), withers (WH) and croup (CH) heights, body length (BL), thoracic (TG) and leg (LG) girths, thoracic (TW) and croup (CW) widths, body depth (BD), rib eye area (REA), fat thickness (FT), and carcass finishing score (CFS). Single-locus association analysis was performed with 11 variants in IGF1, 18 in LEP, and 16 in GH. Moreover, two haplotypes in IGF1 and one haplotype in LEP were evaluated in haplotype association analysis. The single-locus analysis revealed 23 suggestive additive effects (p < 0.05), but no additive effect was found at the Bonferroni threshold. Haplotype association analysis revealed 19 additive effects, of which ten were at the Bonferroni threshold (p < 0.0074). In IGF1 gene, haplotype replacements were associated with ADG 20.51(7.37), CH 4.09(1.21), WH 3.52(1.20), BL 3.94(1.19), TG 3.88(1.30), TW 1.13(0.36), and LG 3.40(1.08); while in the LEP gene the haplotype replacement was associated with BW100 1.83(0.51), BD −2.51(0.56), and CFS −0.24(0.06). Therefore, there are haplotypes in IGF1 and LEP genes associated with body traits in Santa Inês sheep, which can be useful in marker-assisted selection.

Variants in GH, IGF1, and LEP genes associated with body traits in Santa Inês sheep

Growth hormone (GH), insulin-like growth factor 1 (IGF1), and leptin (LEP) can be candidate genes for association studies because they play vital roles in the metabolism process. Thus, this study aimed to identify variants in these genes associated with body traits in Santa Inês sheep. The following were recorded: body weight at 100 (BW100) and 240 days (BW240), average daily gain (ADG), withers (WH) and croup (CH) heights, body length (BL), thoracic (TG) and leg (LG) girths, thoracic (TW) and croup (CW) widths, body depth (BD), rib eye area (REA), fat thickness (FT), and carcass finishing score (CFS). Single-locus association analysis was performed with 11 variants in IGF1, 18 in LEP, and 16 in GH. Moreover, two haplotypes in IGF1 and one haplotype in LEP were evaluated in haplotype association analysis. The single-locus analysis revealed 23 suggestive additive effects (p < 0.05), but no additive effect was found at the Bonferroni threshold. Haplotype association analysis revealed 19 additive effects, of which ten were at the Bonferroni threshold (p < 0.0074). In IGF1 gene, haplotype replacements were associated with ADG 20.51(7.37), CH 4.09(1.21), WH 3.52(1.20), BL 3.94(1.19), TG 3.88(1.30), TW 1.13(0.36), and LG 3.40(1.08); while in the LEP gene the haplotype replacement was associated with BW100 1.83(0.51), BD −2.51(0.56), and CFS −0.24(0.06). Therefore, there are haplotypes in IGF1 and LEP genes associated with body traits in Santa Inês sheep, which can be useful in marker-assisted selection.(AU)

Population structure and inbreeding of Holstein cattle in southern Brazil

The present investigation aimed to evaluate the population structure and inbreeding of Holstein herds in southern Brazil. To carry out the analysis, the Associação Paranaense de Criadores de Bovinos da Raça Holandesa (APCBRH) in Brazil provided the data, which consisted of a pedigree file of 206,796 animals born between 1970 and 2014. Results regarding the following parameters were determined: pedigree integrity, effective number of founders, effective number of ancestors, generation interval, inbreeding coefficient, realized effective population size, and average relatedness coefficient. POPREP and ENDOG v.4.5 software packages were employed to estimate these parameters. Based on the data set, the mean generation interval was found to be 6.3 years, and the average inbreeding coefficient, related to inbred animals, was 4.99%. Furthermore, the realized effective population size varied throughout the time period, ranging from 22 to 114, whereas the rate of inbreeding in this same period showed a decreasing trend towards the later years in the period until 2014. Upon evaluation, average relatedness coefficient was estimated to be 0.71%. Moreover, the effective number of founders and ancestors were estimated as 418 and 400 animals, respectively. According to the level of inbreeding observed, it could be noticed that genetic diversity remains elevated, which will be important to the genetic progress in the Holstein breeding program in Southern Brazil.(AU)

No effects of homeopathy on somatic cell count, bovine milk yield and composition

This study aimed to evaluate the effect of a homeopathic complex, on the reduction of milk somatic cell count, production of milk, fat percentage and protein percentage of milk in lactating Holstein cows, over a period of three months. Twenty cows, in second parity, were randomly assigned in blocks with two treatments, after an initial period of adaptation in the experimental area for 15 days. The cows were distributed into a control group (that did not receive the homeopathic complex) and a treated (that received the homeopathic complex), evaluated for six test-day records. Laboratory analysis of fat and protein were made via the infrared absorption and somatic cell count by flow cytometry, wherein this latest has been transformed into logarithmic scale for statistical analysis. Analysis of variance to test the effects of treatment, testday record and the interaction between these factors, was performed through repeated measures over time. For all traits, there was no significant interaction between treatment and test-day record (p > 0.05) and there was no statistical difference (p > 0.05) between the control and treated groups. The use of the homeopathic complex was not effective in reducing somatic cell count of dairy cows, for the trial period of three months. The use of homeopathy did not interfere significantly with milk yield or the protein percentage in Holstein cows.

No effects of homeopathy on somatic cell count, bovine milk yield and composition

This study aimed to evaluate the effect of a homeopathic complex, on the reduction of milk somatic cell count, production of milk, fat percentage and protein percentage of milk in lactating Holstein cows, over a period of three months. Twenty cows, in second parity, were randomly assigned in blocks with two treatments, after an initial period of adaptation in the experimental area for 15 days. The cows were distributed into a control group (that did not receive the homeopathic complex) and a treated (that received the homeopathic complex), evaluated for six test-day records. Laboratory analysis of fat and protein were made via the infrared absorption and somatic cell count by flow cytometry, wherein this latest has been transformed into logarithmic scale for statistical analysis. Analysis of variance to test the effects of treatment, testday record and the interaction between these factors, was performed through repeated measures over time. For all traits, there was no significant interaction between treatment and test-day record (p > 0.05) and there was no statistical difference (p > 0.05) between the control and treated groups. The use of the homeopathic complex was not effective in reducing somatic cell count of dairy cows, for the trial period of three months. The use of homeopathy did not interfere significantly with milk yield or the protein percentage in Holstein cows.(AU)

Performance of dairy calves raised under two breeding systems / Desempenho de bezerras leiteiras submetidas a dois sistemas de criação

Increasing concern about some animal production systems has placed considerable value on humanitarian breeding systems, aimed at ensuring animal welfare and comfort. Raising calves is one of the most important stages in a milk production system. This study aimed to evaluate and compare the performance of Holstein dairy calves raised by two farming systems: conventional individual (CI) and collective with automatic calf feeder (CACF). Fourteen, 15-day-old Holstein dairy calves having an average initial body weight of 40 kg, were used. The animals were distributed in a completely randomized design with seven animals per treatment. The variables evaluated were the milk and feed intake, body weight, hip height, thoracic circumference and daily weight gain. The average milk intake was lower in the CACF (3.5 L animal-1 day-1) than CI (5.1 L animal-1 day-1) system. However, the feed intake was higher in the CACF (1.205 kg animal-1 day-1) compared to CI (0.910 kg animal-1 day-1) system. Body weight, thoracic circumference, hip height and daily weight gain were similar between the two systems. The CACF raised calves had a higher concentrate intake and lower milk intake than the calves raised under the CI system.(AU)

Nas últimas décadas, a sociedade tem questionado alguns métodos de produção animal e, neste sentido, tem sido valorizado os sistemas de criação humanitária de animais, visando o bem-estar e conforto animal. Considerando que a criação de bezerras constitui uma das fases mais importantes em um sistema de produção de leite, objetivou-se avaliar e comparar o desempenho de bezerras leiteiras da raça Holandesa submetidas aos sistemas de criação individual e coletivo com alimentador automático. Foram utilizadas 14 bezerras da raça Holandesa, com 15 dias de idade e peso corporal inicial médio de 40 kg. Os animais foram distribuídos em delineamento inteiramente casualizado, em dois sistemas de criação: Criação convencional individual (CCI); Criação coletiva com alimentador automático (CCAA), sendo sete animais por tratamento. Avaliaram-se o consumo de leite e de ração, peso corporal, altura de garupa, perímetro torácico e o ganho de peso médio diário. O consumo médio de leite foi menor no sistema CCAA (3,5 L animal-1 dia-1) em relação ao CCI (5,1 L animal-1 dia-1), porém a ingestão de ração foi maior no sistema CCAA (1,205 kg animal-1 dia-1) comparado ao sistema CCI (0,910 kg animal-1 dia-1). As variáveis peso corporal, perímetro torácico, altura de garupa e ganho de peso diário dos bezerros foram semelhantes entre os sistemas. Bezerras criadas coletivamente com o uso de alimentador automático apresentam maior consumo de concentrado e menor consumo de leite. (AU)

Growth curves for Ile de France female sheep raised in feedlot / Curvas de crescimento de fêmeas da raça Ile de France criadas em confinamento

The objective of the present study was to analize the non-linear models that best fit the growth of ewes Ile de France. The experiment was conducted in school farm Capão da Onça, located in city of Ponta Grossa - PR and so, were used data on weight at birth to 210 days of age of 34 females of the breed Ile de France. The animals showed mean weight at birth (PN) of 4,58 kilograms, weaning weight (P60) of 19,58 kilograms and weight at 210 days (P210) equal to 43,18 kilograms, providing daily weight gain (GMD) equal to 0,183 kg/day. The non-linear models used were: Brody, Von Bentarlanffy, Logístic and Gompertz, presenting results, respectively, of 33.5453; 33.7120; 33.6714 and 33.8836 for Error Mean Square (EMS) and 0.9650; 0.8302; 0.9649 and 0.9647 for coefficient of determination (R2). All models tended to describe accordingly the curve of animals growth, but, according to the methods adopted to select the most appropriate model, Von Bertarlanffy showed the best fit. All models presented high and negative correlation between the A and k parameters, indicating that the most precocious animals are less likely to reach elevated weights for 210 days of age.(AU)

O objetivo do presente trabalho foi analisar os modelos não lineares que melhor se ajustam ao crescimento de fêmeas da raça Ile de France. O experimento foi conduzido na Fazenda Escola Capão da Onça, localizada no município de Ponta Grossa - PR e para tanto, foram utilizados dados de peso ao nascimento até os 210 dias de idade de 34 fêmeas da raça Ile de France. Os animais apresentaram médias de peso ao nascer (PN) de 4,58 kg, peso a desmama (P60) de 19,58 kg e peso aos 210 dias (P210) igual a 43,18 kg, proporcionando ganho de peso médio diário do nascimento aos 210 dias (GMD) igual a 0,183 kg/dia. Os modelos não lineares utilizados foram: Brody, Von Bentarlanffy, Logístico e Gompertz, apresentando resultados, respectivamente, de 33,5453; 33,7120; 33,6714 e 33,8836 para o Quadrado Médio do Resíduo (QMR) e de 0,9650; 0,8302; 0,9649 e 0,9647 para o Coeficiente de Determinação (R2). Todos os modelos tenderam a descrever adequadamente a curva de crescimento destes animais, porém, de acordo com os métodos adotados para escolha do modelo mais adequado, Von Bertarlanffy apresentou o melhor ajuste. Todos os modelos demonstraram correlação alta e negativa entre os parâmetros A e k, indicando que animais mais precoces possuem menor probabilidade de atingir pesos mais elevados aos 210 dias de idade.(AU)

Growth curves of texel male lambs

Background: The consumption of lamb meat is growing due to improved farming methods. However, to be economically feasible, the animal should stand out for its precocity, fast finishing and muscular force, such as seen in Texel breed. Besides, knowledge about weight gain and development can facilitate the selection of the best animals, and allow a better fitting to farming systems. Growth curves are an effective method that describes animal development, modeling the relationship between weight and age and help to predict the growth rate. Thus, this study aimed to analyze which nonlinear model, including Brody, Gompertz, Von Bertalanffy and Logistic best describe the growth curve of Texel sheep.Materials, Methods & Results: In this experiment, the lambs were kept in confined system while the ewes, in a semi-extensive system. This study followed 42 Texel male lambs, which were confined from birth to slaughter, and fed concentrated feed (3% of body weight) and corn silage (average 1.5 kg/animal/day), 4 times a day. The lambs were weighed fortnightly, in different classes considered as follows, weight at birth (BW), 15 days (P15), 30 days (P30), 45 days (P45), 60 days (P60), 75 days (P75), 90 days (P90), 105 days (P105), and 120 days (P120), which was defined as the slaughtering weight. The growth curves were determined using the nonlinear models of Brody, Von Bertalanffy, [...](AU)

Growth curves of texel male lambs

Background: The consumption of lamb meat is growing due to improved farming methods. However, to be economically feasible, the animal should stand out for its precocity, fast finishing and muscular force, such as seen in Texel breed. Besides, knowledge about weight gain and development can facilitate the selection of the best animals, and allow a better fitting to farming systems. Growth curves are an effective method that describes animal development, modeling the relationship between weight and age and help to predict the growth rate. Thus, this study aimed to analyze which nonlinear model, including Brody, Gompertz, Von Bertalanffy and Logistic best describe the growth curve of Texel sheep.Materials, Methods & Results: In this experiment, the lambs were kept in confined system while the ewes, in a semi-extensive system. This study followed 42 Texel male lambs, which were confined from birth to slaughter, and fed concentrated feed (3% of body weight) and corn silage (average 1.5 kg/animal/day), 4 times a day. The lambs were weighed fortnightly, in different classes considered as follows, weight at birth (BW), 15 days (P15), 30 days (P30), 45 days (P45), 60 days (P60), 75 days (P75), 90 days (P90), 105 days (P105), and 120 days (P120), which was defined as the slaughtering weight. The growth curves were determined using the nonlinear models of Brody, Von Bertalanffy, [...]

Growth curves for Ile de France ram lambs raised in feedlot / Curvas de crescimento de cordeiros da raça Ile de France criados em confinamento

The objective of this study was to evaluate the nonlinear models that best describe the growth curve of ram lambs Ile de France created in intensive system in the state of Paraná. Therefore, there were weighed fortnightly during the period from February 2013 to June 2013, from birth to slaughter (120 days) of 31 Ile de France ram lambs. Growth curves were obtained by nonlinear models Brody, Von Bertalanffy, Gompertz and Logistic in which parameters were considered maturation rate (K), asymptotic weight (A), age of the animal (t) is given by integration determining the proportion of growth after birth (B) and the proportion of asymptotic value at which the inflection point occurs curve (m) in accordance with the adopted model. The parameters were estimated by Marquardt applied to the NLIN procedure of SAS statistical program and the criteria used to verify the accuracy of the fit of the curves were the mean square of the coefficient of determination. The Brody, Von Bertalanffy, Gompertz and Logistic resulted respectively in 26.4579; 26.1668; 26.136; 26.1582 for the mean square and 0.813; 0.958; 0.958; 0.958 for the coefficient of determination. Considering the criteria assumed the Gompertz model, followed by Logistic and Von Bertalanffy, presented the best fit to describe the growth of Ile de France ram lambs.(AU)

O objetivo com este trabalho foi avaliar os modelos não lineares que melhor descrevem a curva de crescimento de ovinos machos da raça Ile de France criados em confinamento no estado do Paraná. Para tanto, foram realizadas pesagens quinzenais no período de fevereiro de 2013 a junho de 2013, desde o nascimento até o abate (120 dias) de 31 machos da raça Ile de France. As curvas de crescimento foram obtidas pelos modelos não lineares de Brody, Von Bertalanffy, Gompertz e Logístico em que foram considerados os parâmetros da taxa de maturação (K), peso assintótico (A), idade do animal (t), constante de integração que determina a proporção de crescimento após nascimento (B) e proporção do valor assintótico em que ocorre o ponto de inflexão da curva (m), de acordo com o modelo adotado. Os parâmetros foram estimados pelo método Marquardt aplicado ao procedimento NLIN do programa estatístico SAS e os critérios utilizados para verificar a precisão do ajuste das curvas foram o quadrado médio do resíduo e o coeficiente de determinação. Os modelos Brody, Von Bertalanffy, Gompertz e Logístico resultaram respectivamente em 26,4579; 26,1668; 26,1360 e 26,1582 para o quadrado médio do resíduo e 0,8130; 0,9580; 0,9587 e 0,9580 para o coeficiente de determinação.(AU)

Growth curves for Ile de France ram lambs raised in feedlot / Curvas de crescimento de cordeiros da raça Ile de France criados em confinamento

The objective of this study was to evaluate the nonlinear models that best describe the growth curve of ram lambs Ile de France created in intensive system in the state of Paraná. Therefore, there were weighed fortnightly during the period from February 2013 to June 2013, from birth to slaughter (120 days) of 31 Ile de France ram lambs. Growth curves were obtained by nonlinear models Brody, Von Bertalanffy, Gompertz and Logistic in which parameters were considered maturation rate (K), asymptotic weight (A), age of the animal (t) is given by integration determining the proportion of growth after birth (B) and the proportion of asymptotic value at which the inflection point occurs curve (m) in accordance with the adopted model. The parameters were estimated by Marquardt applied to the NLIN procedure of SAS statistical program and the criteria used to verify the accuracy of the fit of the curves were the mean square of the coefficient of determination. The Brody, Von Bertalanffy, Gompertz and Logistic resulted respectively in 26.4579; 26.1668; 26.136; 26.1582 for the mean square and 0.813; 0.958; 0.958; 0.958 for the coefficient of determination. Considering the criteria assumed the Gompertz model, followed by Logistic and Von Bertalanffy, presented the best fit to describe the growth of Ile de France ram lambs.

O objetivo com este trabalho foi avaliar os modelos não lineares que melhor descrevem a curva de crescimento de ovinos machos da raça Ile de France criados em confinamento no estado do Paraná. Para tanto, foram realizadas pesagens quinzenais no período de fevereiro de 2013 a junho de 2013, desde o nascimento até o abate (120 dias) de 31 machos da raça Ile de France. As curvas de crescimento foram obtidas pelos modelos não lineares de Brody, Von Bertalanffy, Gompertz e Logístico em que foram considerados os parâmetros da taxa de maturação (K), peso assintótico (A), idade do animal (t), constante de integração que determina a proporção de crescimento após nascimento (B) e proporção do valor assintótico em que ocorre o ponto de inflexão da curva (m), de acordo com o modelo adotado. Os parâmetros foram estimados pelo método Marquardt aplicado ao procedimento NLIN do programa estatístico SAS e os critérios utilizados para verificar a precisão do ajuste das curvas foram o quadrado médio do resíduo e o coeficiente de determinação. Os modelos Brody, Von Bertalanffy, Gompertz e Logístico resultaram respectivamente em 26,4579; 26,1668; 26,1360 e 26,1582 para o quadrado médio do resíduo e 0,8130; 0,9580; 0,9587 e 0,9580 para o coeficiente de determinação.

Utilização de diferentes metodologias para avaliação genética de bovinos de corte / Utilization of different methodologies for genetic evaluation of beef cattle

Com as constantes mudanças do sistema produtivo de bovinos de corte, e um mercado consumidor ainda mais exigente, o enfoque sobre a escolha de animais que apresentem qualidade e rendimento de carcaça é cada vez maior. Para que as reivindicações dos frigoríficos sejam atendidas, o criador necessita de ferramentas de avaliação genética que possam identificar com mais precisão os touros que serão, de fato, melhoradores para as características desejáveis. Com isso, este trabalho teve como objetivo: (i) Estimar os componentes de variância e covariância, e os parâmetros genéticos para a característica de musculosidade em animais da raça Nelore; (ii) Estimar os componentes de variância e covariância, e os parâmetros genéticos para características de desenvolvimento ponderal (peso ao nascimento, peso a desmama, ganho de peso aos 345 dias) e reprodutivo (circunferência escrotal) em animais da raça Nelore; (iii) Estimar a correlação entre as características de musculosidade, desenvolvimento ponderal e reprodutivo; (iv) Comparar as metodologias que consideram o grupo de manejo a desmama como efeito fixo e aleatório; (v) Comparar as metodologias uni, bi e multicaracterística e avaliar as vantagens em incluir nos programas de seleção, através do cálculo de resposta correlacionada, a característica de musculosidade; (vi) Estimar as DEP´s para as características de musculosidade, desenvolvimento ponderal e reprodutivo; (vii) Comparar as metodologias multicaracterística e bivariadas na avaliação genética de touros, através do cálculo de perda de eficiência de seleção

With the constant changes in the beef cattle production system, and an even more demanding consumer market, the focus on the carcass yield and quality is increasing. For the slaughters claims to be met, the breeder needs a tool that can identify the bulls that will be, in fact, the improvers to those specific features. Therefore, this project aims to: (i) Estimate the variance and covariance components, and the genetic parameters for the muscle score trait in Nellore animals; (ii) Estimate the variance and covariance components, and the genetic parameters for the growth traits (birth weight, weaning weight, post-weaning gain) and reproductive traits (scrotal circumference) in Nellore animals; (iii) Estimate the correlation between muscle score, growth and reproductive traits; (iv) Compare methodologies that consider the weaning management group as fixed and random effects; (v) Compare uni, bi and multi-trait methodologies and evaluate the advantages to include in the animal breeding programs, by the correlated response, the muscle score trait; (vi) Estimate the EPD\'s for muscle score, growth and reproductive traits and (vii) Compare the multi-trait and bivariate methodologies in the genetic evaluation of bulls through the calculation of selection efficiency loss

Performance of dairy calves raised under two breeding systems / Desempenho de bezerras leiteiras submetidas a dois sistemas de criação

Increasing concern about some animal production systems has placed considerable value on humanitarian breeding systems, aimed at ensuring animal welfare and comfort. Raising calves is one of the most important stages in a milk production system. This study aimed to evaluate and compare the performance of Holstein dairy calves raised by two farming systems: conventional individual (CI) and collective with automatic calf feeder (CACF). Fourteen, 15-day-old Holstein dairy calves having an average initial body weight of 40 kg, were used. The animals were distributed in a completely randomized design with seven animals per treatment. The variables evaluated were the milk and feed intake, body weight, hip height, thoracic circumference and daily weight gain. The average milk intake was lower in the CACF (3.5 L animal-1 day-1) than CI (5.1 L animal-1 day-1) system. However, the feed intake was higher in the CACF (1.205 kg animal-1 day-1) compared to CI (0.910 kg animal-1 day-1) system. Body weight, thoracic circumference, hip height and daily weight gain were similar between the two systems. The CACF raised calves had a higher concentrate intake and lower milk intake than the calves raised under the CI system.

Nas últimas décadas, a sociedade tem questionado alguns métodos de produção animal e, neste sentido, tem sido valorizado os sistemas de criação humanitária de animais, visando o bem-estar e conforto animal. Considerando que a criação de bezerras constitui uma das fases mais importantes em um sistema de produção de leite, objetivou-se avaliar e comparar o desempenho de bezerras leiteiras da raça Holandesa submetidas aos sistemas de criação individual e coletivo com alimentador automático. Foram utilizadas 14 bezerras da raça Holandesa, com 15 dias de idade e peso corporal inicial médio de 40 kg. Os animais foram distribuídos em delineamento inteiramente casualizado, em dois sistemas de criação: Criação convencional individual (CCI); Criação coletiva com alimentador automático (CCAA), sendo sete animais por tratamento. Avaliaram-se o consumo de leite e de ração, peso corporal, altura de garupa, perímetro torácico e o ganho de peso médio diário. O consumo médio de leite foi menor no sistema CCAA (3,5 L animal-1 dia-1) em relação ao CCI (5,1 L animal-1 dia-1), porém a ingestão de ração foi maior no sistema CCAA (1,205 kg animal-1 dia-1) comparado ao sistema CCI (0,910 kg animal-1 dia-1). As variáveis peso corporal, perímetro torácico, altura de garupa e ganho de peso diário dos bezerros foram semelhantes entre os sistemas. Bezerras criadas coletivamente com o uso de alimentador automático apresentam maior consumo de concentrado e menor consumo de leite.

Growth curves for Ile de France female sheep raised in feedlot / Curvas de crescimento de fêmeas da raça Ile de France criadas em confinamento

The objective of the present study was to analize the non-linear models that best fit the growth of ewes Ile de France. The experiment was conducted in school farm Capão da Onça, located in city of Ponta Grossa - PR and so, were used data on weight at birth to 210 days of age of 34 females of the breed Ile de France. The animals showed mean weight at birth (PN) of 4,58 kilograms, weaning weight (P60) of 19,58 kilograms and weight at 210 days (P210) equal to 43,18 kilograms, providing daily weight gain (GMD) equal to 0,183 kg/day. The non-linear models used were: Brody, Von Bentarlanffy, Logístic and Gompertz, presenting results, respectively, of 33.5453; 33.7120; 33.6714 and 33.8836 for Error Mean Square (EMS) and 0.9650; 0.8302; 0.9649 and 0.9647 for coefficient of determination (R2). All models tended to describe accordingly the curve of animals growth, but, according to the methods adopted to select the most appropriate model, Von Bertarlanffy showed the best fit. All models presented high and negative correlation between the A and k parameters, indicating that the most precocious animals are less likely to reach elevated weights for 210 days of age.

O objetivo do presente trabalho foi analisar os modelos não lineares que melhor se ajustam ao crescimento de fêmeas da raça Ile de France. O experimento foi conduzido na Fazenda Escola Capão da Onça, localizada no município de Ponta Grossa - PR e para tanto, foram utilizados dados de peso ao nascimento até os 210 dias de idade de 34 fêmeas da raça Ile de France. Os animais apresentaram médias de peso ao nascer (PN) de 4,58 kg, peso a desmama (P60) de 19,58 kg e peso aos 210 dias (P210) igual a 43,18 kg, proporcionando ganho de peso médio diário do nascimento aos 210 dias (GMD) igual a 0,183 kg/dia. Os modelos não lineares utilizados foram: Brody, Von Bentarlanffy, Logístico e Gompertz, apresentando resultados, respectivamente, de 33,5453; 33,7120; 33,6714 e 33,8836 para o Quadrado Médio do Resíduo (QMR) e de 0,9650; 0,8302; 0,9649 e 0,9647 para o Coeficiente de Determinação (R2). Todos os modelos tenderam a descrever adequadamente a curva de crescimento destes animais, porém, de acordo com os métodos adotados para escolha do modelo mais adequado, Von Bertarlanffy apresentou o melhor ajuste. Todos os modelos demonstraram correlação alta e negativa entre os parâmetros A e k, indicando que animais mais precoces possuem menor probabilidade de atingir pesos mais elevados aos 210 dias de idade.

Estimação dos parâmetros genéticos do peso adulto em matrizes da raça Nelore / Genetic parameters estimation for mature weight in Nelore beef cattle

O estudo das características produtivas visa a obtenção de animais possuidores de genótipos com potencial para altas produções mas que sejam também adaptados ao meio ambiente de criação extensiva no Brasil. Esses animais produtivos e adaptados poderiam otimizar os custos, tornando assim, sua criação sustentável em escala comercial. Apesar das características reprodutivas serem de extrema importância como objetivo de seleção, sua utilização não tem sido ampla em programas de melhoramento genético por serem consideradas de baixa herdabilidade. Entre as características produtivas existentes em bovinos de corte pode ser citada a caracterítica de peso adulto, que deve ser avaliado e monitorado o aumento do tamanho das fêmeas pela resposta indireta a seleção para peso, afim de confrontar os resultados economicamente. Dentro deste contexto foram avaliados dados de 74.547 animais com o objetivo de analisar o peso adulto e o peso adulto com repetibilidade (PAVr) em animais Nelore estimando a herdabilidade de características de desenvolvimento ponderal, utilizando modelos lineares; Estimar a correlação entre peso adulto (PAV) e características de peso ao sobreano (PS), conformação (CONF), precocidade (PREC), musculosidade (MUSC) e altura de garupa (AG); Determinar se há ou não vantagem em incluir o peso adulto em programas de seleção na raça Nelore. Os componentes de variância e de covariância foram estimados pelo método de máxima verossimilhança restrita (MTDFREML) utilizando-se o modelo animal. As estimativas dos coeficientes de herdabilidade foram de 0,43 para PAV e 0,41 para PAVr; 0,38 para PS; 0,23 para CONF; 0,19 para PREC; 0,22 para MUSC e 0,35 para AG. Os coeficientes de correlação genética obtidos variaram de 0,37 a 0,97. Os resultados sugerem que ganhos genéticos podem ser obtidos com a seleção para a característica de peso adulto, em monitoramento do tamanho de fêmeas na raça Nelore. A correlação entre as característica em estudo demonstra haver uma tendência de alteração das características de tamanho a partir da seleção para peso adulto

The study of the productive traits aims the obtention of animals that have genotypes with potencial for high productions but that are also adaptable to the environment of the extensive creation in Brazil. These productive and adaptable animals could improve the costs, making therefore, their creation sustainable on a commercial scale. Although the reproductive characteristics have an extremely importance as an objective of the selection, its utilization have not been ample in genetic improvement programs for being considered as a low heritability trait. Between the productive traits existent in beef cattle it can be cited the mature weight trait, that must be evaluated and monitorated for the size increase control of the females by the indirect answer to weight selection, in order to confront, economically, the results. In this context it was evaluated data from 74.547 animals with the objective of analyze the mature weight and the adult weight with repeated measurements (MWr) in Nelore animals estimating the heritability of the ponderal development traits, using linear models; Estimate the correlation between mature weight (MW) and the post-weaning weight trait (PW), conformation (CONF), precocity (PREC), musculature (MUSC) and hip height (HH); Determine if there is an advantage in the inclusion of the mature weight in selection programs of the Nelore breed. The components of variance and covariance were estimated by the method of Restricted Maximum Likelihood Multiple Trait Derivative Free (MTDFREML) using the animal model. The estimation of the heritability coefficients were 0,43 for MW and 0,41 for MWr; 0,38 for PW; 0,23 for CONF; 0,19 for PREC; 0,22 for MUSC and 0,35 for HH. The genetic correlation coefficients varied from 0,37 to 0,97. The results suggest that genetic gains can be obtained with the selection for the mature weight characteristic, with the monitoration of the female sizes for Nelore breed. The correlation between the characteristics in study shows that there is a tendency for alteration in size characteristics through the selection for mature weight