RESUMEN
Investigating factors that could affect milk production of cows is an important way to improve the efficiency of production systems. This purpose of this study was to verify and quantify the influence of calf sex on milk production and lactation length in herds of Holstein, Gir, and Guzera cows. Data from 10,780 lactations of 4,807 Holstein cows that calved between 2001 and 2013; 18,898 lactations of 13,172 Gir cows that calved between 1985 and 2013; and 5,277 lactations of 3,972 Guzera cows that calved between 1987 and 2013 were used. Both the accumulated 305-day milk yield (P305) and the length of the lactation period up to 305 days (DL305) were evaluated. Analysis of variance was performed by the least squares method using the GLM procedure in the SAS statistical program. The P305 was not influenced by the sex of the calf in the Holstein breed. However in the zebu breeds (Gir and Guzera), both P305 and DL305 were significantly affected (P 0.01) by the sex of the calf, with higher production and average length of lactation in cows that calved males. In addition, a significant difference was also nested within sex of calf and age at first calving (P 0.05) in the Gir breed. The results indicate that for the zebu breeds, calf sex influences production characteristics.
A investigação de fatores que interferem na produção de vacas leiteiras é de grande importância para eficiência dos sistemas de produção. O objetivo do trabalho foi verificar e quantificar a influência do sexo do bezerro sobre produção de leite e sobre a duração da lactação em rebanhos das raças Holandesa, Gir Leiteiro e Guzerá. Foram avaliadas 10.780 lactações de 4.807 vacas Holandesas, paridas entre 2001 e 2013; 18.898 lactações de 13.172 vacas Gir Leiteiro paridas de 1985 a 2013 e 5.277 lactações ocorridas entre 1987 e 2013, de 3.972 vacas Guzerá. As características estudadas foram produção de leite acumulada em 305 dias e duração da lactação (até 305 dias). A análise de variância foi realizada pelo método de quadrados mínimos, através do procedimento GLM do programa estatístico SAS. A produção de leite acumulada aos 305 dias (P305) na raça Holandesa não foi influenciada pelo sexo do bezerro. Entretanto, para os animais de origem zebuína (Gir leiteiro e Guzerá), ambas as características foram significativamente influenciadas (P 0,01) pelo sexo do bezerro, sendo observadas maiores produções de leite e duração de lactação para vacas que pariram machos. Também foi observada diferença significativa do sexo do bezerro aninhado dentro de idade da vaca ao parto (P 0,05) para a raça Gir leiteiro. Estes resultados indicam que para as raças zebuínas, o sexo do bezerro influe
RESUMEN
Investigating factors that could affect milk production of cows is an important way to improve the efficiency of production systems. This purpose of this study was to verify and quantify the influence of calf sex on milk production and lactation length in herds of Holstein, Gir, and Guzera cows. Data from 10,780 lactations of 4,807 Holstein cows that calved between 2001 and 2013; 18,898 lactations of 13,172 Gir cows that calved between 1985 and 2013; and 5,277 lactations of 3,972 Guzera cows that calved between 1987 and 2013 were used. Both the accumulated 305-day milk yield (P305) and the length of the lactation period up to 305 days (DL305) were evaluated. Analysis of variance was performed by the least squares method using the GLM procedure in the SAS statistical program. The P305 was not influenced by the sex of the calf in the Holstein breed. However in the zebu breeds (Gir and Guzera), both P305 and DL305 were significantly affected (P 0.01) by the sex of the calf, with higher production and average length of lactation in cows that calved males. In addition, a significant difference was also nested within sex of calf and age at first calving (P 0.05) in the Gir breed. The results indicate that for the zebu breeds, calf sex influences production characteristics.
A investigação de fatores que interferem na produção de vacas leiteiras é de grande importância para eficiência dos sistemas de produção. O objetivo do trabalho foi verificar e quantificar a influência do sexo do bezerro sobre produção de leite e sobre a duração da lactação em rebanhos das raças Holandesa, Gir Leiteiro e Guzerá. Foram avaliadas 10.780 lactações de 4.807 vacas Holandesas, paridas entre 2001 e 2013; 18.898 lactações de 13.172 vacas Gir Leiteiro paridas de 1985 a 2013 e 5.277 lactações ocorridas entre 1987 e 2013, de 3.972 vacas Guzerá. As características estudadas foram produção de leite acumulada em 305 dias e duração da lactação (até 305 dias). A análise de variância foi realizada pelo método de quadrados mínimos, através do procedimento GLM do programa estatístico SAS. A produção de leite acumulada aos 305 dias (P305) na raça Holandesa não foi influenciada pelo sexo do bezerro. Entretanto, para os animais de origem zebuína (Gir leiteiro e Guzerá), ambas as características foram significativamente influenciadas (P 0,01) pelo sexo do bezerro, sendo observadas maiores produções de leite e duração de lactação para vacas que pariram machos. Também foi observada diferença significativa do sexo do bezerro aninhado dentro de idade da vaca ao parto (P 0,05) para a raça Gir leiteiro. Estes resultados indicam que para as raças zebuínas, o sexo do bezerro influe
RESUMEN
SUMMARY The objectives were to evaluate diets containing levels of in natura linseed oil (1.0, 3.8 and 5.2% of diet DM) on carcass characteristics and meat cuts, and correlate these results with in vivo body measures of 14 heifers and 15 steers Nellore x Canchim. The animals were confined individually receiving 20% of sugar cane as roughage and 80% concentrate, in a complete randomized block (oil content x sexual condition). All animals of each block were slaughtered when the average body weight reached 500 kg. No interactions between treatments were observed. Add up to 5.2% of linseed oil in diet of crossbred cattle increases the weight of the main carcass cuts, reduce the loss during cooling and does not change the level of renal pelvic-inguinal fat. Heifers and steers Nellore x Canchim produce similar amounts of weight and yield hindquarters meat. Along with body weight, the extent pelviano contour is the most indicated to assist the formation of homogeneous lots for slaughter or trial, because showed the best correlation with the characteristics used in the Brazilian market of meat, such as weight and carcass yield.
RESUMO Os objetivos foram avaliar dietas contendo teores de óleo de linhaça in natura (1,0; 3,8 e 5,2% da MS da dieta) sobre as características da carcaça e cortes cárneos, e correlacionar esses resultados com medidas corporaisin vivo de 14 fêmeas e 15 machos castrados Nelore x Canchim. Os animais foram confinados individualmente recebendo 20% de cana-de-açúcar como volumoso e 80% de concentrado, em um delineamento de blocos ao acaso (teores de óleo x condição sexual). Todos os animais de cada bloco foram abatidos quando o peso corporal médio atingiu 500 kg. Não foram observadas interações entre os fatores estudados. Acrescentar até 5,2% de óleo de linhaçain natura da dieta de bovinos cruzados aumenta o peso dos principais cortes cárneos da carcaça, reduz as perdas no resfriamento e não altera o teor de gordura renal-pélvica-inguinal. Fêmeas e machos castrados Nelore x Canchim produzem quantidades similares de carne do traseiro especial, em peso e rendimento. Juntamente com o peso corporal, a medida do contorno pelviano é a mais indicada para auxiliar na formação de lotes homogêneos para o abate ou experimentação, por apresentar as melhores correlações com as características utilizadas na comercialização brasileira de carne, como peso e rendimento da carcaça.
RESUMEN
SUMMARY The objectives were to evaluate diets containing levels of in natura linseed oil (1.0, 3.8 and 5.2% of diet DM) on carcass characteristics and meat cuts, and correlate these results with in vivo body measures of 14 heifers and 15 steers Nellore x Canchim. The animals were confined individually receiving 20% of sugar cane as roughage and 80% concentrate, in a complete randomized block (oil content x sexual condition). All animals of each block were slaughtered when the average body weight reached 500 kg. No interactions between treatments were observed. Add up to 5.2% of linseed oil in diet of crossbred cattle increases the weight of the main carcass cuts, reduce the loss during cooling and does not change the level of renal pelvic-inguinal fat. Heifers and steers Nellore x Canchim produce similar amounts of weight and yield hindquarters meat. Along with body weight, the extent pelviano contour is the most indicated to assist the formation of homogeneous lots for slaughter or trial, because showed the best correlation with the characteristics used in the Brazilian market of meat, such as weight and carcass yield.
RESUMO Os objetivos foram avaliar dietas contendo teores de óleo de linhaça in natura (1,0; 3,8 e 5,2% da MS da dieta) sobre as características da carcaça e cortes cárneos, e correlacionar esses resultados com medidas corporaisin vivo de 14 fêmeas e 15 machos castrados Nelore x Canchim. Os animais foram confinados individualmente recebendo 20% de cana-de-açúcar como volumoso e 80% de concentrado, em um delineamento de blocos ao acaso (teores de óleo x condição sexual). Todos os animais de cada bloco foram abatidos quando o peso corporal médio atingiu 500 kg. Não foram observadas interações entre os fatores estudados. Acrescentar até 5,2% de óleo de linhaçain natura da dieta de bovinos cruzados aumenta o peso dos principais cortes cárneos da carcaça, reduz as perdas no resfriamento e não altera o teor de gordura renal-pélvica-inguinal. Fêmeas e machos castrados Nelore x Canchim produzem quantidades similares de carne do traseiro especial, em peso e rendimento. Juntamente com o peso corporal, a medida do contorno pelviano é a mais indicada para auxiliar na formação de lotes homogêneos para o abate ou experimentação, por apresentar as melhores correlações com as características utilizadas na comercialização brasileira de carne, como peso e rendimento da carcaça.
RESUMEN
In dairy farming, the productive performance of lactating cows is directly related to the efficiency of the production system. In this respect, studies in different areas investigating animal production try to understand the determinant factors of milk production. Many studies have shown a high correlation between milk production of cows and performance of their calves; however, few studies have addressed the influence of calf sex on milk production. With the objective to evaluate the influence of fetal sex on the milk production of Holstein cows, the present study analyzed cumulative milk yield data provided by the Agrindus Farm in Descalvado, São Paulo. A total of 10,780 calvings of 4,807 cows that had calved between April 2001 and October 2013 and their cumulative yields during lactation according to offspring sex were evaluated. The PROC GLM procedure of the SAS software (SAS Inst., Inc., Cary, NC) was used for analysis. The contemporary group was defined as year and month of calving, with a minimum of 5 observations per group. In addition to contemporary group, the effects of management group and calving order of the cow were included in the model. Mean cumulative yields were 9,800.79 and 9,802.95 kg for cows that had given birth to males and females, respectively. There was no significant difference (P=0.9519) in cumulative milk yield of cows during the study period as a
O artigo não apresenta resumo em português.
RESUMEN
The body weight (BW) determination is important to evaluate the growth of animals, their nutritional condition and reproduction and to establish the slaughter time and the sale value of the animal. The chest girth (CG) could be an alternative to determine the body weight of sheep on properties that do not have scales. The objective of this study was to investigate the feasibility of using chest girth to determine the estimated body weight (EBW). The data file contained 1762 records of body weight (BW) and chest girth (CG) from 426 Santa Ines breed sheep, belonging to eight herds located in Southeastern Brazil. The chest girth was measured using the sternum and the withers as base, passing the tape measure behind the shoulder. Body weights were related to CG values through linear regressions using the software Statistical Analysis Systems (SAS Inst., Inc., Cary, NC). The age classes 1, 2, 3, were defined respectively as: 0 to 12 months; 13 to 22 months; over 34 months. The regression equation used to predict the body weight through chest girth in different age classes was y = b0 + b1x, where y is the dependent variable EBW, x is the independent variable CG, b0 is the intercept, b1 is the slope of the equation that defines the relationship between EBW and CG. The other variables were constant. The regression equations for specific age groups of animals were: Class 1 EBW = -42.201
O artigo não apresenta resumo em português.
RESUMEN
Performance evaluation of adapted animals to local conditions for economic traits is essential for the preservation of species and their genetic resources. The size of Morada Nova breed herds have decreased over time, becoming restricted to a few regions. Other races have been used with higher frequency because of their production and adaptation, and are important as a source of food and income for local communities. The objective of this research was to evaluate the application of nonlinear models to describe the growth curve of Morada Nova sheep. Records of 1604 weights of 250 lambs from Nova Odessa municipality, being 934 repeated measurements of female and 670 repeated measurements of male, obtained between 2012-2013 were used. The average birth weight observed was 2.50 ± 0.690 kg. The nonlinear models used to adjust the data were Brody Yt = A (1 - be-kt); Von Bertalanffy Yt = A (1 - be-kt)3; Richards Yt = A (1 - be-kt)m; Logistic Yt = A (1 + e-kt)-m and Gompertz Yt = Ae -be(-kt). The models were fitted by Gauss-Newton using the NLIN procedure of SAS (SAS Inst., Inc., Cary, NC). The parameters that make up the functions are Y = body weight at the age t; A = asymptotic weight that represents the average adulthood weight; K = Maturation rate, an indicator of the speed with which the animal approaches its adult size, maturity of the individual in relation to age is the fractio
O artigo não apresenta resumo em português.
RESUMEN
Performance evaluation of adapted animals to local conditions for economic traits is essential for the preservation of species and their genetic resources. The size of Morada Nova breed herds have decreased over time, becoming restricted to a few regions. Other races have been used with higher frequency because of their production and adaptation, and are important as a source of food and income for local communities. The objective of this research was to evaluate the application of nonlinear models to describe the growth curve of Morada Nova sheep. Records of 1604 weights of 250 lambs from Nova Odessa municipality, being 934 repeated measurements of female and 670 repeated measurements of male, obtained between 2012-2013 were used. The average birth weight observed was 2.50 ± 0.690 kg. The nonlinear models used to adjust the data were Brody Yt = A (1 - be-kt); Von Bertalanffy Yt = A (1 - be-kt)3; Richards Yt = A (1 - be-kt)m; Logistic Yt = A (1 + e-kt)-m and Gompertz Yt = Ae -be(-kt). The models were fitted by Gauss-Newton using the NLIN procedure of SAS (SAS Inst., Inc., Cary, NC). The parameters that make up the functions are Y = body weight at the age t; A = asymptotic weight that represents the average adulthood weight; K = Maturation rate, an indicator of the speed with which the animal approaches its adult size, maturity of the individual in relation to age is the fractio
O artigo não apresenta resumo em português.
RESUMEN
The body weight (BW) determination is important to evaluate the growth of animals, their nutritional condition and reproduction and to establish the slaughter time and the sale value of the animal. The chest girth (CG) could be an alternative to determine the body weight of sheep on properties that do not have scales. The objective of this study was to investigate the feasibility of using chest girth to determine the estimated body weight (EBW). The data file contained 1762 records of body weight (BW) and chest girth (CG) from 426 Santa Ines breed sheep, belonging to eight herds located in Southeastern Brazil. The chest girth was measured using the sternum and the withers as base, passing the tape measure behind the shoulder. Body weights were related to CG values through linear regressions using the software Statistical Analysis Systems (SAS Inst., Inc., Cary, NC). The age classes 1, 2, 3, were defined respectively as: 0 to 12 months; 13 to 22 months; over 34 months. The regression equation used to predict the body weight through chest girth in different age classes was y = b0 + b1x, where y is the dependent variable EBW, x is the independent variable CG, b0 is the intercept, b1 is the slope of the equation that defines the relationship between EBW and CG. The other variables were constant. The regression equations for specific age groups of animals were: Class 1 EBW = -42.201
O artigo não apresenta resumo em português.
RESUMEN
In dairy farming, the productive performance of lactating cows is directly related to the efficiency of the production system. In this respect, studies in different areas investigating animal production try to understand the determinant factors of milk production. Many studies have shown a high correlation between milk production of cows and performance of their calves; however, few studies have addressed the influence of calf sex on milk production. With the objective to evaluate the influence of fetal sex on the milk production of Holstein cows, the present study analyzed cumulative milk yield data provided by the Agrindus Farm in Descalvado, São Paulo. A total of 10,780 calvings of 4,807 cows that had calved between April 2001 and October 2013 and their cumulative yields during lactation according to offspring sex were evaluated. The PROC GLM procedure of the SAS software (SAS Inst., Inc., Cary, NC) was used for analysis. The contemporary group was defined as year and month of calving, with a minimum of 5 observations per group. In addition to contemporary group, the effects of management group and calving order of the cow were included in the model. Mean cumulative yields were 9,800.79 and 9,802.95 kg for cows that had given birth to males and females, respectively. There was no significant difference (P=0.9519) in cumulative milk yield of cows during the study period as a
O artigo não apresenta resumo em português.
RESUMEN
In a sheep production system, the growth-related characteristics have direct relationship to both, quantity and quality of meat. The objective of this study was to evaluate the application of non-linear models to report the growth curve of Santa Inês sheep. Weights of 140 females, born from2010 to 2012, from a single herd at Cravinhos- SP were used. The weights were measured from birth to about one year of age and the ages were grouped together in biweekly classes. The average weight observed at birth was of 3.77±0.92 kg. The non-linear models utilized in the data adjustment were the Brody, Gompertz, Logistic and Von Bertalanffy models, adjusted by the Gauss-Newton method by means of NLIN procedure, available in SAS software. The parameters which compose the functions, Wt (kg) is the weight in time t (days); A (kg) is the asymptotic weight when age tends to infinity; b is an integration constant, related to the initial weights of the animals and not well defined biological interpretation, and k is the maturity rate. The average estimates for A and k, are the most important from an zootechnical parameters point of view, mainly because heavier females tend to create faster growing sheep. All the models evaluated reached convergence. The quality of the models adjustment was done by error mean square (EMS) means. From the EMS results , the Gompertz model showed the best adjustment,
O artigo não apresenta resumo em português.
RESUMEN
The objective of this work was to study the influence of the use of bovine somatotropin (bST) on milk yield (MP305) and genetic evaluation of MP305 of Holstein Cattle. Data from 474 bulls and observations concerning 3.341 lactations of 1.271 cows during the period from 1999 to 2003 were used. Variance analysis was performed by the GLM SAS procedure (2003) and parameters in one animal model. The heritability estimates for model 1(bST as a fixed effect) and model 2 (absence of this effect) were respectively 0.26 and 0.23 for the two analyses and correlations between estimated breeding values for bulls sets a (all evaluated), b (best 20%), c (best 10%) and d (best 5%) were, respectively, 0.9484, 0.9829, 0.9752 and 0.8974. Variance analysis of variance showed that the average PL305 increased significantly (P 0.0001) with the increase number of bST applications. The Spearman correlations coefficients between breeding values of bulls were high, with or without the use of bST in the model, indicating that the use of this technology does not affect the classification of genetically evaluated bulls.
O objetivo do presente trabalho foi estudar a influência do uso da somatotropina bovina (bST) sobre a produção de leite (PL305) e a avaliação genética da PL305 de bovinos da raça Holandesa. Foram utilizados dados referentes a 474 touros e observações referentes a 3341 lactações de 1271 vacas, durante o período de 1999 a 2003. A análise de variância foi realizada pelo procedimento GLM do SAS (2003) e os parâmetros genéticos sob modelo animal unicaracterístico. As estimativas de herdabilidades para o modelo 1 (bST como efeito fixo) e modelo 2 (ausência desse efeito) foram respectivamente de 0,26 e 0,23 e a correlações entre os valores genéticos preditos para os conjuntos de touros a (todos avaliados), b (os melhores 20%), c (os melhores 10%) e d (os melhores 5%) foram, respectivamente, 0,9484, 0,9829, 0,9752 e 0,8974. A análise de variância demonstrou que as médias de PL305 aumentaram significativamente (P 0,0001), com o aumento do número de aplicações do bST. As altas correlações de Spearman entre os valores genéticos dos touros, considerando-se ou não o uso do bST no modelo, indicam que o uso desta tecnologia não interfere na classificação dos touros avaliados geneticamente.
RESUMEN
The objective of this study was to evaluate the frequency of clinical mastitis (CM), in high production Holstein cows, as well as the environmental factors that favoring its incidence. The average milk production of 305 days, according to the class of mastitis was estimated by the method of least squares. The frequencies of clinical mastitis (CM) events were analyzed according to the calving sequences (1-6), year of calving, season and stage of lactation, and infected quarter (right anterior, left anterior, right posterior, left posterior). The frequency of CM ranged from 11.39% in the first calving to 21.18% in the third. 58.56% of mastitis cases occurred in the wet season, and 41.44% occurred in the dry season. The final lactation stage (200 to 300 days) was the period with the highest occurrence of CM (45.33%). The quarter posterior had a higher frequency CM (54.25%). Animals with higher levels of milk production of 305 days showed highest occurrence of CM. We must find a balance between milk production and mastitis in order to increase profitability. The study of the periods of greatest frequency clinical mastitis events is essential for dairy farming, to direct a program to control this disease.
O objetivo deste estudo foi verificar as frequências de mastite clínica (MC) em vacas Holandesas de alta produção de leite, bem como os fatores ambientais que influenciam sua incidência. A média da produção de leite aos 305 dias de acordo com a classe de mastite foi estimada pelo método de quadrados mínimos. As frequências de MC foram analisadas de acordo com as ordens do parto (1 a 6), ano do parto, estação do ano, fase da lactação, e quarto infectado (anterior direito, anterior esquerdo, posterior direito, posterior esquerdo). A frequência da MC por ordem de parto variou de 11,39% no primeiro parto a 21,18% no terceiro parto. 58,56 % dos casos de mastite ocorreram no período das águas e 41,44% no período da seca. O terço final da lactação foi o período com maior ocorrência de casos de MC (45,33%). Os quartos posteriores apresentaram maior frequência de MC (54,25%). Os animais com maiores níveis de produção de leite aos 305 dias (9.466,42 Kg) foram os que apresentaram maior incidência de mastite clínica. Deve-se encontrar um ponto de equilíbrio entre a produção de leite e a mastite a fim de aumentar a rentabilidade da produção. O estudo dos períodos de maior frequência de ocorrência de mastite clínica é fundamental para a pecuária leiteira, para o direcionamento de um programa de controle dessa doença.
RESUMEN
In a sheep production system, the growth-related characteristics have direct relationship to both, quantity and quality of meat. The objective of this study was to evaluate the application of non-linear models to report the growth curve of Santa Inês sheep. Weights of 140 females, born from2010 to 2012, from a single herd at Cravinhos- SP were used. The weights were measured from birth to about one year of age and the ages were grouped together in biweekly classes. The average weight observed at birth was of 3.77±0.92 kg. The non-linear models utilized in the data adjustment were the Brody, Gompertz, Logistic and Von Bertalanffy models, adjusted by the Gauss-Newton method by means of NLIN procedure, available in SAS software. The parameters which compose the functions, Wt (kg) is the weight in time t (days); A (kg) is the asymptotic weight when age tends to infinity; b is an integration constant, related to the initial weights of the animals and not well defined biological interpretation, and k is the maturity rate. The average estimates for A and k, are the most important from an zootechnical parameters point of view, mainly because heavier females tend to create faster growing sheep. All the models evaluated reached convergence. The quality of the models adjustment was done by error mean square (EMS) means. From the EMS results , the Gompertz model showed the best adjustment,
O artigo não apresenta resumo em português.
RESUMEN
The milk yield has been the most selected trait in dairy cattle breeding programs. However various studies have shown a decline in adaptive and longevity traits in herds that are under selection for improving production, especially in taurine breeds, as the Holstein, who was highly selected for milk production. The aim of this study was to estimate genetic parameters for first lactation 305-day milk yield (Y305) and for longevity traits and to verify the association among them, in high production Holstein cows. The data sets used were from Agrindus Farm, with calving occurring between 1989 and 2005. The traits analyzed were Y305, productive life (PL), calculated as the length of lactation days from the first day of lactation until the culling, and age at culling (AC). Variance components were estimated by Restricted Maximum Likelihood, applying multi-trait animal model. Heritability estimates for Y305, PL and AC were, respectively, 0.35, 0.07 and 0.10. Heritability estimates for PL and AC suggest small genetic variability to get genetic gains by direct selection for these traits, because they are influenced by decisions of voluntary and involuntary culling, being largely affected by factors related to the environment. It is difficult to measure these traits because it is necessary to evaluate culling of animals and causes of culling. The magnitude of the heritability estimate f
O artigo não apresenta resumo em português.
RESUMEN
The milk yield has been the most selected trait in dairy cattle breeding programs. However various studies have shown a decline in adaptive and longevity traits in herds that are under selection for improving production, especially in taurine breeds, as the Holstein, who was highly selected for milk production. The aim of this study was to estimate genetic parameters for first lactation 305-day milk yield (Y305) and for longevity traits and to verify the association among them, in high production Holstein cows. The data sets used were from Agrindus Farm, with calving occurring between 1989 and 2005. The traits analyzed were Y305, productive life (PL), calculated as the length of lactation days from the first day of lactation until the culling, and age at culling (AC). Variance components were estimated by Restricted Maximum Likelihood, applying multi-trait animal model. Heritability estimates for Y305, PL and AC were, respectively, 0.35, 0.07 and 0.10. Heritability estimates for PL and AC suggest small genetic variability to get genetic gains by direct selection for these traits, because they are influenced by decisions of voluntary and involuntary culling, being largely affected by factors related to the environment. It is difficult to measure these traits because it is necessary to evaluate culling of animals and causes of culling. The magnitude of the heritability estimate f
O artigo não apresenta resumo em português.
RESUMEN
Feed regimens alter muscle growth rate, hence they might impact the proteolytic system involved in tenderization during meat conditioning. The aim of this project was to verify the effects of feed restriction regimens on muscular and animal growth and their impact on postmortem myofibrillar fragmentation. The regimens were: 1) Feeding ad libitum for 11 d (Al/2); 2) Feed restriction (60% of Net Energy for maintenance - NEm) for 11 d (Rt/2); 3) Ad libitum for 22 d (Al); 4) Ad libitum for 4 d and feed restriction (60% NEm) for 18 d (Rt); 5) Ad libitum for 19 d and 3 d of fast (Ft); 6) Feed restriction (60% NEm) for 11 d and ad libitum until 22 d (Ral). The regimens Al/2 and Rt/2 had different intestine weights (19.3 ± 1.1 and 15.8 ± 1.9 g, respectively; P 0.07). At 22 d, Al animals had higher (P 0.07) intestine weight (21.8 ± 3.8). Moreover, Ral animals had heavier intestine (19.9 ± 1.5) as compared to Rt (16.6 ± 1.6) or Ft (12.8 ± 1.9). The intestine/live weight percentage ratio was lower (P 0.05) for Ft (6.3%) as compared to Al (8.4%) and to Ral (9.2%), but it was similar to Rt (7.6%). Liver weight (g) in the Ral (9.5 ± 1.1) did not differ from Al (10.7 ± 2.5) or Rt (8.5 ± 1.1), although the two latter were different (P 0.05). There was an effect of feed restriction over muscle protein degradation verified by Myofibrillar Fragmentation Index (MFI). The animals at Rt, Ft or Ral showed the lowest MFI 0d (42 ± 1.9; 40 ± 2.7; 40 ± 3.6; respectively) and MFI 5d (77 ± 2.7; 74 ± 3.0; 74 ± 2.9; respectively) as compared to Al, whose indexes were 54 ± 3.0 and 82 ± 3.3. Even though the MFI 5d were lower for the restricted animals, the rates of fragmentation postmortem were higher. Feed restriction altered myofibrillar protein degradation, reflected in lower extended fragmentation of the myofibrils.
Regimes alimentares alteram a taxa de crescimento muscular, e podem impactar o sistema proteolítico envolvido no amaciamento da carne durante maturação. O objetivo do trabalho foi verificar a existência de reflexo do regime alimentar sobre crescimento animal e muscular, e o impacto na fragmentação miofibrilar pós-morte. Os regimes foram: 1) Consumo ad libitum por 11 d (Al/2); 2) Restrição alimentar (60% energia de mantença - NEm) por 11 d (Rt/2); 3) Ad libitum por 22 d (Al); 4) Ad libitum por 4 d e restrição alimentar (60% NEm) por 18 d (Rt); 5) Ad libitum por 19 d e 3 d de jejum (Ft); 6) Restrição alimentar (60% NEm) por 11 d e ad libitum até 22 d (Ral). Os regimes Al/2 e Rt/2 apresentaram diferenças no peso de intestino (19,3 ± 1,1 e 15,8 ± 1,9 g, respectivamente; P 0,07). Nos 22 d, o regime Al resultou em intestinos mais pesados (P 0,07; 21,8 ± 3,8). Além disso, os animais do regime Ral tiveram maiores pesos de intestino (19,9 ± 1,5) comparados com Rt (16,6 ± 1,6) ou Ft (12,8 ± 1,9). A relação intestino/peso vivo foi menor (P 0,05) para Ft (6,3%) comparado com Al (8,4%) e com Ral (9,2%), mas foi similar ao Rt (7,6%). O peso do fígado (g) nos animais do regime Ral (9,5 ± 1,1) não diferiu do regime Al (10,7 ± 2,5) ou Rt (8,5 ± 1,1), sendo que os dois últimos foram diferentes (P 0,05). Houve efeito da restrição alimentar sobre a degradação da proteína muscular verificada pelo Índice de Fragmentação miofibrilar (MFI). Os animais de Rt, Ft ou Ral mostraram os menores valores de MFI 0d (42 ± 1,9; 40 ± 2,7; 40 ± 3,6; respectivamente) e MFI 5d (77 ± 2,7; 74 ± 3,0; 74 ± 2,9; respectivamente) comparados com Al onde os índices foram 54 ± 3,0 e 82 ± 3,3, respectivamente. Embora os animais que experimentaram alguma restrição alimentar tenham apresentado menor MFI 5d, as sua taxas de fragmentação pós-morte foram maiores. Restrição alimentar alterou a degradação da proteína miofibrilar, refletida na menor extensão da fragmentação das miofibrilas.
RESUMEN
Feed regimens alter muscle growth rate, hence they might impact the proteolytic system involved in tenderization during meat conditioning. The aim of this project was to verify the effects of feed restriction regimens on muscular and animal growth and their impact on postmortem myofibrillar fragmentation. The regimens were: 1) Feeding ad libitum for 11 d (Al/2); 2) Feed restriction (60% of Net Energy for maintenance - NEm) for 11 d (Rt/2); 3) Ad libitum for 22 d (Al); 4) Ad libitum for 4 d and feed restriction (60% NEm) for 18 d (Rt); 5) Ad libitum for 19 d and 3 d of fast (Ft); 6) Feed restriction (60% NEm) for 11 d and ad libitum until 22 d (Ral). The regimens Al/2 and Rt/2 had different intestine weights (19.3 ± 1.1 and 15.8 ± 1.9 g, respectively; P 0.07). At 22 d, Al animals had higher (P 0.07) intestine weight (21.8 ± 3.8). Moreover, Ral animals had heavier intestine (19.9 ± 1.5) as compared to Rt (16.6 ± 1.6) or Ft (12.8 ± 1.9). The intestine/live weight percentage ratio was lower (P 0.05) for Ft (6.3%) as compared to Al (8.4%) and to Ral (9.2%), but it was similar to Rt (7.6%). Liver weight (g) in the Ral (9.5 ± 1.1) did not differ from Al (10.7 ± 2.5) or Rt (8.5 ± 1.1), although the two latter were different (P 0.05). There was an effect of feed restriction over muscle protein degradation verified by Myofibrillar Fragmentation Index (MFI). The animals at Rt, Ft or Ral showed the lowest MFI 0d (42 ± 1.9; 40 ± 2.7; 40 ± 3.6; respectively) and MFI 5d (77 ± 2.7; 74 ± 3.0; 74 ± 2.9; respectively) as compared to Al, whose indexes were 54 ± 3.0 and 82 ± 3.3. Even though the MFI 5d were lower for the restricted animals, the rates of fragmentation postmortem were higher. Feed restriction altered myofibrillar protein degradation, reflected in lower extended fragmentation of the myofibrils.
Regimes alimentares alteram a taxa de crescimento muscular, e podem impactar o sistema proteolítico envolvido no amaciamento da carne durante maturação. O objetivo do trabalho foi verificar a existência de reflexo do regime alimentar sobre crescimento animal e muscular, e o impacto na fragmentação miofibrilar pós-morte. Os regimes foram: 1) Consumo ad libitum por 11 d (Al/2); 2) Restrição alimentar (60% energia de mantença - NEm) por 11 d (Rt/2); 3) Ad libitum por 22 d (Al); 4) Ad libitum por 4 d e restrição alimentar (60% NEm) por 18 d (Rt); 5) Ad libitum por 19 d e 3 d de jejum (Ft); 6) Restrição alimentar (60% NEm) por 11 d e ad libitum até 22 d (Ral). Os regimes Al/2 e Rt/2 apresentaram diferenças no peso de intestino (19,3 ± 1,1 e 15,8 ± 1,9 g, respectivamente; P 0,07). Nos 22 d, o regime Al resultou em intestinos mais pesados (P 0,07; 21,8 ± 3,8). Além disso, os animais do regime Ral tiveram maiores pesos de intestino (19,9 ± 1,5) comparados com Rt (16,6 ± 1,6) ou Ft (12,8 ± 1,9). A relação intestino/peso vivo foi menor (P 0,05) para Ft (6,3%) comparado com Al (8,4%) e com Ral (9,2%), mas foi similar ao Rt (7,6%). O peso do fígado (g) nos animais do regime Ral (9,5 ± 1,1) não diferiu do regime Al (10,7 ± 2,5) ou Rt (8,5 ± 1,1), sendo que os dois últimos foram diferentes (P 0,05). Houve efeito da restrição alimentar sobre a degradação da proteína muscular verificada pelo Índice de Fragmentação miofibrilar (MFI). Os animais de Rt, Ft ou Ral mostraram os menores valores de MFI 0d (42 ± 1,9; 40 ± 2,7; 40 ± 3,6; respectivamente) e MFI 5d (77 ± 2,7; 74 ± 3,0; 74 ± 2,9; respectivamente) comparados com Al onde os índices foram 54 ± 3,0 e 82 ± 3,3, respectivamente. Embora os animais que experimentaram alguma restrição alimentar tenham apresentado menor MFI 5d, as sua taxas de fragmentação pós-morte foram maiores. Restrição alimentar alterou a degradação da proteína miofibrilar, refletida na menor extensão da fragmentação das miofibrilas.
RESUMEN
The objective of this work was to evaluate the influence of the genetic group of crossbreeding from birth up to 330 kg of liveweight on the average daily gain (ADG). The herd was constituted by crossbreeding Gyr Holsteins animals and the crossing system was rotational crossings with repetitions of Holstein sires. The data used was collected in the herd during 6 years. Analyses of variance were carried out by the least square method, with models wich included the effects of year, seasons of calving, genetic group and their interactions. Females were assigned to genetic groups according to percentage of Holstein in their breed composition: G1 (53 to 62.5), G2 (62.5 to 81) and G3 (84 to 94). Animals were weighted monthly and the ADGs were calculated from birth to 2 months, from 2 to 6 months, from 6 to 12 months and from 12 months to 330kg of liveweight. There were no effects of genetic group (P > .05) on the ADG from birth to 2 and from 2 to 6 months of age. There was no interaction between the genetic group and season of birth. Considering animals from 6 to 12 months of age, the genetic group by season interaction was significant (P .05): animals G1 born from October to March had higher daily gain than animals born from March to September. Considering animals from 12 months of age to 330kg of liveweight, there was significant difference between ADG within different genet
O objetivo deste trabalho foi avaliar os efeitos de diferentes grupos genéticos sobre o ganho de peso diário de novilhas do nascimento até 330 kg de peso vivo. O rebanho era constitu- ído por animais cruzados das raças Holandesa e Gir, sendo praticado o cruzamento alternado com repetição da raça Holandesa. Os dados analisados foram coletados em 6 anos de 1992 a 1997. Análises de variância foram realizadas por intermédio do método dos quadrados mínimos, usando- se modelos que incluíram efeitos de ano, mês de nascimento da bezerra e grupo genético. Os grupos genéticos G1; G2 e G3 foram representados por animais com composição genética entre 53 a 62,5%; 62,5 a 81% e 84 a 94% da raça Holandesa, respectivamente. As pesagens foram realizadas mensalmente e o ganho de peso diário analisados do nascimento aos 2 meses, de 2 aos 6 meses, de 6 aos 12 meses e de 12 meses aos 330kg de peso vivo. Nos períodos do nascimento a 2 meses e de 2 a 6 meses não foi observado efeito do grupo genético sobre o ganho de peso e não houveram interações significativas com a estação do ano em que as bezerras nasceram. No período de 6 a 12 meses houve interação significativa entre grupo genético e ano de nascimento e entre grupo gené- tico e estação do ano, sendo que animais G1 nascidos entre os meses de Outubro a Março ganharam mais peso que animais G1 nascidos no período seco (Abril a Setembro). Na fase de
RESUMEN
The objective was to evaluate milk yield and dry matter intake (DM) by crossbred cows fed with sugar cane variety IAC 86-2480 as exclusive roughage source and concentrate levels of 8; 4 or 2kg per cow, daily. Twenty one crossbred cows, in two lactation phases were individually fed. There were two adaptation periods, one of 14 days when cows were fed with sugar cane added of 0.5% of NPN and 8kg of concentrate and a second period of 14 days when cows were allotted to three dietary treatments with 8; 4 and 2kg of concentrate. The composition of concentrate were 19.6% of soybean meal, 29.4 of whole soybean, 49% of corn and 2% of mineral misture. The experimental period was 21 days. There was difference (P 0.01) between treatments for DM intake and milk yield. The results were 18.83; 16.11 and 13.72kg of milk/cow/day; 18.31; 14.66 and 11.55kg DM/cow/day and intake of 3.37; 2.89 and 2.32% of BW for cows when fed with 8; 4 and 2kg of concentrate, respectively. No difference was observed on milk composition, except for milk protein and milk urea contents. The results were 3.01; 2.82 and 2.73% protein and, 9.80; 7.40 and 6.39mg dL-1 for milk urea for 8; 4 and 2kg of concentrate treatments, respectively. The level of concentrate feeding affected milk yield and milk composition of cows fed with sugar cane as exclusive roughage source.
O objetivo foi avaliar a produção de leite e o consumo de matéria seca (MS) de vacas mestiças alimentadas com a cana-de-açúcar variedade IAC86-2480, como volumoso exclusivo, fornecendo-se três níveis de concentrado, ou seja, 2, 4 e 8kg por vaca, diariamente. Vinte e uma vacas mestiças, em duas fases da lactação, foram manejadas em um galpão com cochos individuais. Houve dois períodos de adaptação, um de 14 dias, quando as vacas receberam cana-de-açú- car adicionando-se 0,5% de NNP e 8kg de concentrado e outro, de 14 dias, quando as vacas foram alimentadas de acordo com os tratamentos, isto é a cana com NNP e 8; 4 e 2kg de concentrado. A composição do concentrado era 19,6% de farelo de soja, 29,4% de soja, 49% de milho e 2% de minerais. O período experimental foi de 21 dias. Houve diferença (P 0,01) para produção de leite, consumo total de MS e consumo de MS em relação ao peso vivo (PV). Os resultados foram 18,83; 16,11 e 13,72kg de leite/vaca/dia, 18,31; 14,66 e 11,55kg de MS/vaca/dia e consumo de 3,37; 2,89 e 2,32% do PV para vacas que receberam 8; 4 e 2kg de concentrado, respectivamente. Não houve diferença, entre os tratamentos, para consumo de MS da cana. Os tratamentos influenciaram a composição do leite, apenas em seus teores de proteína e a uréia. Os resultados foram 3,02; 2,82 e 2,74% de proteína e 9,78; 7,40 e 6,39 mg dl-1 de uréia para os tratamentos 8; 4 e 2kg de