RESUMO
The rational use of nutrients is a key factor for the sustainability of agricultural systems. This study aimed to analyze the nitrogen balance and use efficiency, and the valorization of organic residues within integrated systems, in comparison to conventional agricultural and livestock systems. The experiment was assembled in a randomized blocks design with three replicates. Six production systems were compared, grain maize production (CROP) and pasture for beef cattle production (LS), and four ICLS (Integrated Crop-Livestock System) for grain maize and pastures for beef cattle, in 2 years. In order to estimate the nutrients balance, inputs, and outputs at farm levels were considered, and with the results obtained for nutrient balance, the use efficiency was calculated. The CROP presented higher nutrient use efficiency (1.43 kg/ha-1), but at the same time, it resulted in negative contributions for the nutrient balance (-97 kg/ha-1) because of lower amounts of nitrogen in the organic residues (188 kg/ha-1) and lower valuation. The LS and ICLS provided a higher amount of nitrogen (983 kg/ha-1; mean ± 921 kg/ha-1) and valuation of organic residues. The presence of components such as pastures and the animal contribute to a positive production system, while reducing the needs for chemical fertilizers.
Assuntos
Fertilizantes , Gado , Agricultura/métodos , Animais , Bovinos , Fazendas , Nitrogênio , SoloRESUMO
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.
RESUMO
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.
RESUMO
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.
RESUMO
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.
RESUMO
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.
RESUMO
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.
RESUMO
The experiment was undertaken at the Faculty of Agrarian and Veterinary Sciences (FCAV) Jaboticabal, São Paulo State, Brazil, during winter-spring-summer of 2001-2002, to determine the fractionation of nitrogen and carbohydrates in Tifton 85 (Cynodon dactylon Vanderyst x Cynodon nlemfuensis (L.) Pers), exclusively or oversown with winter annual forage species. Treatments comprised bristle oat (Avena strigosa Schreb), yellow oat (Avena byzantina C. Koch), triticale (X Triticosecale Wittmack), bristle oat + yellow oat, bristle oat + triticale, yellow oat + triticale, bristle oat + yellow oat + triticale seeded in Tifton 85 and sole crop (control). Experimental design was composed of completely randomized blocks with three replications. Fodder was cut 20 cm high (presence of winter forage) and 10 cm high (Tifton 85 pasture). Crude protein, total carbohydrate and the fractions of nitrogen compounds and carbohydrates were determined. Decrease was reported in the levels of chemical compounds in winter forage species and in Tifton 85 during the evaluation periods. The content of nitrogen compounds and carbohydrates varied widely during the evaluation period according to the morphological characteristics of grass species and botanical composition of pastures.
RESUMO
The experiment was undertaken at the Faculty of Agrarian and Veterinary Sciences (FCAV) Jaboticabal, São Paulo State, Brazil, during winter-spring-summer of 2001-2002, to determine the fractionation of nitrogen and carbohydrates in Tifton 85 (Cynodon dactylon Vanderyst x Cynodon nlemfuensis (L.) Pers), exclusively or oversown with winter annual forage species. Treatments comprised bristle oat (Avena strigosa Schreb), yellow oat (Avena byzantina C. Koch), triticale (X Triticosecale Wittmack), bristle oat + yellow oat, bristle oat + triticale, yellow oat + triticale, bristle oat + yellow oat + triticale seeded in Tifton 85 and sole crop (control). Experimental design was composed of completely randomized blocks with three replications. Fodder was cut 20 cm high (presence of winter forage) and 10 cm high (Tifton 85 pasture). Crude protein, total carbohydrate and the fractions of nitrogen compounds and carbohydrates were determined. Decrease was reported in the levels of chemical compounds in winter forage species and in Tifton 85 during the evaluation periods. The content of nitrogen compounds and carbohydrates varied widely during the evaluation period according to the morphological characteristics of grass species and botanical composition of pastures.
RESUMO
The trial was carried through at APTA Regional, Ribeirao Preto, SP, to compare the degradability of dry matter (DM) and neutral detergent fiber (NDF) of elephant grass Guaçu and Tanzania guinea grass sampled from extrusa and hand-plucked. The pasture management was rotational grazing. Five rumen-canulated milked cows were used for thetrial at some different times. The soluble fraction (A), the insoluble fraction potentially degradable (B), degradation rate (Kd) and the effective degradation (ED) was estimated. The statistical analysis was made considering a factorial 2x2 and split plot design (two years). There were interaction between years and grass species and sample way. The Guaçu presented higher (P 0.01) B fraction than Tanzania just for the 1st year (68.26 and 63.90% of DM) but no difference was found on the 2nd year (63.30 and 63.07% of DM). No effect of grass species was found for the other studied variables. The fraction A (% of DM), Kd(%/h) and ED5%/h (% of DM) were 14.01; 14.68; 3.21; 3.28; 40.54 and 39.05 on the 1st year and 18.01; 16.48; 2.81; 2.83; 39.34 and 39.16 on the 2nd year for the Guaçu and Tanzania, respectively. For DM, the extrusa samples presented higher results for all variables except the B fraction, for the two years. The NDF of B fraction was higher (P 0.01) for the Guaçu than Tanzania both years. No difference was found for the other variabl
O experimento foi realizado na APTA Regional, Ribeirão Preto, SP, para comparar a degradabilidade da matéria seca (MS) e da fibra em detergente neutro (FDN) do capim-elefante Guaçu e capim-tanzânia, amostrados na forma de extrusa ou pastejo simulado, sob sistema rotacionado. Cinco vacas em lactação, canuladas no rúmen foram usadas para as incubações, em diferentes tempos. As frações solúvel (A), potencialmente degradável (B), taxa de degradação da fração B (Kd) e a degradabilidade efetiva (DE) foram estimadas. O delineamento utilizado foi esquema fatorial 2 x 2, com repetição no tempo (dois anos). Houve efeito da interação ano e espécie forrageira e ano e forma de amostragem. O Guaçu apresentou maior fração B do que o Tanzânia no 1º ano (68,26 e 63,90% da MS), não havendo diferença no 2º ano (60,30 e 63,07% da MS). As demais variáveis da matéria seca, nos dois anos, não foram influenciadas pela espécie de capim. A fração A (% da MS), Kd (%/h) e a DE 5% (% da MS) foram 14,01; 14,68; 3,21; 3,28; 40,54 e 39,05 no 1º ano e 18,01; 16,48; 2,81; 2,83; 39,34 e 39,16 no 2º ano, para o Guaçu e o tanzânia, respectivamente. A extrusa apresentou resultados superiores para todas as variáveis, da matéria seca, exceto a fração B, nos dois anos. A FDN da fração B foi maior no Guaçu ambos os anos, não havendo diferença para as outras variáveis. Apenas no 2º ano, a extrusa apresentou maior B e ma