RESUMO

Addressing the improvement of the textile characteristics is currently required in natural color production of alpaca fiber. This study analyses the possibility of implementing a genetic improvement program aiming to reduce the fiber diameter and the percentage of medullation in natural colors under the incomplete definition of the natural colors of alpaca fiber. The study considers color determination analysis in three separate steps. The first step aimed at finding the values of lightness (L*), red/green axis (a*), yellow/blue axis (b*) of three-dimensional space of color and chroma (C*ab), tone (h*ab) and color difference (ΔE) with mathematical models for the description of the coat color. The second analysis is aimed at estimating genetic parameters of color traits and their correlation with fiber traits (fiber diameter, standard deviations and percentage of medullation - PM). The third step was to determine the potential selection criteria of breeding animals based on the parameters provided by a three-dimensional space values regarding the coat color assignment in alpacas. The colorimetric data were taken using a Chroma meter device analyzing 3 008 records from Huacaya type alpacas, collected between 2018 and 2019. In the first objective of the study, the color traits were subjected to a principal component analysis. The analysis of variance components and the estimation of genetic parameters were carried out using a restricted maximum likelihood procedure. The discriminant analysis was used for the correct assignment of the coat color. The principal component analysis results showed that the L*, a*, b*, h*ab and ΔE values can be grouped into two Principal Components (PC) to describe the color, where the L* value is mainly distributed in PC2, b* is distributed in PC1, while a* is distributed in both components. The heritabilities found were 0.144, 0.128, 0.151, 0.104 and 0.152 for L*, a*, b*, PC1 and PC2. The relevant genetic correlations were between L*-PM (-0.557) and b*-PM (-0.622). The discriminant analysis showed a high percentage of correct assignment in white (99.15%) and black (99.19%) coat colors for Huacaya type alpacas, while for the intermediate colors, the accuracy was lower. The three analyses showed that there is no pure natural color, but a range of color variation. It is better to use the values of the three-dimensional space and within them, the values of L* and b* are potential selection criteria to be included in a genetic improvement program.

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One of the main factors to establish productivity of grazing cattle is the estimation of forage intake. For this, the most widely used technique is based on the estimation of fecal output using chromium dioxide as external marker. However, quantification can be expensive and sometimes not precise due to the methodology used for this purpose. Therefore, the aim of this study was to validate the colorimetric method for chromium quantification and to implement it in the estimation of fecal output in grazing cattle. The temperature, the digestion time and the wavelength for the measurement were evaluated. The method was validated for selectivity, linearity, detection and quantification limits, precision, accuracy, and stability. Results showed that temperature and digestion time are critical to improve sensitivity and quantification limits. The validation demonstrated that the method is suitable for the quantification of Cr2O3 in a wide range of concentrations, being statistically comparable with a reference method, and offering a reliable low cost and easy to implement alternative, to estimate fecal output in bovine digestibility studies.(AU)

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RESUMO

One of the main factors to establish productivity of grazing cattle is the estimation of forage intake. For this, the most widely used technique is based on the estimation of fecal output using chromium dioxide as external marker. However, quantification can be expensive and sometimes not precise due to the methodology used for this purpose. Therefore, the aim of this study was to validate the colorimetric method for chromium quantification and to implement it in the estimation of fecal output in grazing cattle. The temperature, the digestion time and the wavelength for the measurement were evaluated. The method was validated for selectivity, linearity, detection and quantification limits, precision, accuracy, and stability. Results showed that temperature and digestion time are critical to improve sensitivity and quantification limits. The validation demonstrated that the method is suitable for the quantification of Cr2O3 in a wide range of concentrations, being statistically comparable with a reference method, and offering a reliable low cost and easy to implement alternative, to estimate fecal output in bovine digestibility studies.

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RESUMO

This study evaluated pre-slaughter stress and its influence on the stress indicators, quality characteristics and sensory characteristics of Nile tilapia fillets. To this end, two experiments were conducted: (1) two transportation times (60 and 240 min), with a density of 200 kg m−3, were compared to control treatment fish (in which the fish were removed from the net cage and immediately euthanized); and (2) two transportation densities (100 and 400 kg m−3), transported for 180 min, compared with control treatment fish. In experiment 1, the transportation time of 60 min resulted in higher levels of serum cortisol and plasma glucose compared to the transportation time of 240 min and the control. Fish fillets transported for 240 min had higher water-holding capacity, less water loss by pressure and higher levels of juiciness compared to fish transported for 60 min. Color, pH and water loss during cooking were not affected by transportation time. In experiment 2, transportation densities of 100 and 400 kg m−3 did not significantly affect the stress indicators nor the instrumental quality parameters of the fillets, but fish transported at 400 kg m−3 showed better visual acceptance by panellists.(AU)

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Hemoglobin is a protein present in erythrocytes, used in the transport of respiratory gases. This protein can be measured through laboratory tests, thus it is an important tool in health assessment of domestic animals. The hemoglobin test protocol by cyano-met hemoglobin method describes that its measurement can be made during a period of up to seven days, but the laboratorial routine shows a reduction in the values before this period. The objective of this study was to determine what the actual maximum period to measure hemoglobin levels in cattle is without changes. Nineteen healthy bovine animals were used, males and females, who underwent venous blood collection via jugular puncture. Samples were analyzed by manual colorimetric. Analyses were made every 24 hours during a fourteen days-interval. During this interval the samples were kept under refrigeration. Hemoglobin levels varied from 8.546 to 22.456 g/dL. Compared to baseline, there were no significant changes in hemoglobin concentration during the investigated period of time, indicating that its measurement can be performed after 14 days of storage.(AU)

A hemoglobina é uma proteína presente nos eritrócitos, que realiza o transporte dos gases respiratórios. Exames laboratoriais mensuram esta proteína, sendo uma importante variável para a avaliação de saúde em animais domésticos. O protocolo do teste da determinação da concentração de hemoglobina pelo método ciano-metemoglobina descreve que sua mensuração pode ser realizada em um prazo de até sete dias, porém a rotina laboratorial mostra redução nos valores antes do período proposto. O objetivo deste trabalho foi avaliar qual o real prazo máximo para mensurar as concentrações de hemoglobina em bovinos sem que haja alterações em seus valores. Foram utilizados 19 bovinos sadios, machos e fêmeas, os quais foram submetidos a colheita de sangue venoso por meio de punção da jugular externa. As amostras foram analisadas por meio de colorimetria manual. As análises foram feitas a cada 24 horas no intervalo de 14 dias. Durante este intervalo as amostras foram mantidas sob refrigeração. A variação da concentração de hemoglobina foi de 8,546 a 22,456 g/dL. Em comparação aos valores basais, não houve significativas alterações na concentração de hemoglobina durante o intervalo de tempo investigado, indicando que sua mensuração pode ser realizada em até 14 dias pós colheita.(AU)

Assuntos

RESUMO

Hemoglobin is a protein present in erythrocytes, used in the transport of respiratory gases. This protein can be measured through laboratory tests, thus it is an important tool in health assessment of domestic animals. The hemoglobin test protocol by cyano-met hemoglobin method describes that its measurement can be made during a period of up to seven days, but the laboratorial routine shows a reduction in the values before this period. The objective of this study was to determine what the actual maximum period to measure hemoglobin levels in cattle is without changes. Nineteen healthy bovine animals were used, males and females, who underwent venous blood collection via jugular puncture. Samples were analyzed by manual colorimetric. Analyses were made every 24 hours during a fourteen days-interval. During this interval the samples were kept under refrigeration. Hemoglobin levels varied from 8.546 to 22.456 g/dL. Compared to baseline, there were no significant changes in hemoglobin concentration during the investigated period of time, indicating that its measurement can be performed after 14 days of storage.

A hemoglobina é uma proteína presente nos eritrócitos, que realiza o transporte dos gases respiratórios. Exames laboratoriais mensuram esta proteína, sendo uma importante variável para a avaliação de saúde em animais domésticos. O protocolo do teste da determinação da concentração de hemoglobina pelo método ciano-metemoglobina descreve que sua mensuração pode ser realizada em um prazo de até sete dias, porém a rotina laboratorial mostra redução nos valores antes do período proposto. O objetivo deste trabalho foi avaliar qual o real prazo máximo para mensurar as concentrações de hemoglobina em bovinos sem que haja alterações em seus valores. Foram utilizados 19 bovinos sadios, machos e fêmeas, os quais foram submetidos a colheita de sangue venoso por meio de punção da jugular externa. As amostras foram analisadas por meio de colorimetria manual. As análises foram feitas a cada 24 horas no intervalo de 14 dias. Durante este intervalo as amostras foram mantidas sob refrigeração. A variação da concentração de hemoglobina foi de 8,546 a 22,456 g/dL. Em comparação aos valores basais, não houve significativas alterações na concentração de hemoglobina durante o intervalo de tempo investigado, indicando que sua mensuração pode ser realizada em até 14 dias pós colheita.

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The objective of this work was to evaluate combinations between acid digestion techniques and spectrophotometric quantification to measure chromium concentration in cattle feces. Digestion techniques were evaluated based on the use of nitric and perchloric acids, sulfuric and perchloric acids, and phosphoric acid. The chromium quantification in the solutions was performed by colorimetry and by atomic absorption spectrophotometry (AAS). When AAS was used, the addition of calcium chloride to the solutions as a releasing agent was also evaluated. Several standard samples containing known chromium contents were produced (0, 2, 4, 6, 8 and 10g of chromium per kg of feces) using cattle feces obtained from three different animals to evaluate the accuracy of the different combinations of techniques. The accuracy was evaluated by adjusting a simple linear regression model of the estimated values on the actual values of chromium content in the standard samples. Regardless of the digestion technique, the chromium content estimates in the standard samples obtained by colorimetry were not accurate (P<0.05). Considering the AAS quantification, the digestion techniques based on nitric and perchloric acids and based on sulfuric and perchloric acids provided complete chromium recovery (P>0.05). The use of the digestion technique in phosphoric acid provided incomplete recovery of the fecal chromium (P<0.05). Subsequently, the digestion techniques in nitric and perchloric acids and digestion in sulfuric and perchloric acids, both evaluated by AAS, were compared using 84 cattle feces samples. The results indicate that these techniques provide similar (P>0.05) fecal chromium contents.

Objetivou-se avaliar combinações entre técnicas de digestão ácida e quantificação espectrofotométrica para estimar a concentração de cromo em amostras de fezes bovinas. Foram avaliadas técnicas de digestão baseadas na utilização de ácidos nítrico e perclórico, ácidos sulfúrico e perclórico e ácido fosfórico. A quantificação da concentração de cromo nas soluções foi realizada por colorimetria e por espectrofotometria de absorção atômica (EAA). Na quantificação por EAA, foi avaliada a adição de cloreto de cálcio como agente de liberação. Amostras-padrão contendo quantidades conhecidas de cromo foram produzidas (0, 2, 4, 6, 8 e 10g de cromo por kg de fezes) utilizando-se fezes bovinas obtidas de três animais diferentes, para avaliar a acurácia das diferentes técnicas. A acurácia foi avaliada pelo ajustamento de modelo de regressão linear simples dos valores estimados sobre os valores reais de cromo nas amostras-padrão. Independentemente da técnica de digestão ácida, as estimativas da concentração de cromo nas amostras-padrão obtidas por colorimetria não foram acuradas (P<0,05). Considerando-se a quantificação de cromo por EAA, as técnicas de digestão baseadas nos ácidos nítrico e perclórico e nos ácidos sulfúrico e perclórico promoveram completa recuperação de cromo (P>0,05). A utilização da técnica de digestão em ácido fosfórico promoveu recuperação incompleta do cromo fecal (P<0,05). Posteriormente, as técnicas de digestão em ácidos nítrico e perclórico e em ácidos sulfúrico e perclórico, ambas avaliadas por EAA, foram comparadas utilizando-se 84 amostras de fezes bovinas. Os resultados indicam que aquelas combinações de técnicas promovem resultados similares (P>0,05) da concentração fecal de cromo.

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RESUMO

The objective of this work was to evaluate combinations between acid digestion techniques and spectrophotometric quantification to measure chromium concentration in cattle feces. Digestion techniques were evaluated based on the use of nitric and perchloric acids, sulfuric and perchloric acids, and phosphoric acid. The chromium quantification in the solutions was performed by colorimetry and by atomic absorption spectrophotometry (AAS). When AAS was used, the addition of calcium chloride to the solutions as a releasing agent was also evaluated. Several standard samples containing known chromium contents were produced (0, 2, 4, 6, 8 and 10g of chromium per kg of feces) using cattle feces obtained from three different animals to evaluate the accuracy of the different combinations of techniques. The accuracy was evaluated by adjusting a simple linear regression model of the estimated values on the actual values of chromium content in the standard samples. Regardless of the digestion technique, the chromium content estimates in the standard samples obtained by colorimetry were not accurate (P<0.05). Considering the AAS quantification, the digestion techniques based on nitric and perchloric acids and based on sulfuric and perchloric acids provided complete chromium recovery (P>0.05). The use of the digestion technique in phosphoric acid provided incomplete recovery of the fecal chromium (P<0.05). Subsequently, the digestion techniques in nitric and perchloric acids and digestion in sulfuric and perchloric acids, both evaluated by AAS, were compared using 84 cattle feces samples. The results indicate that these techniques provide similar (P>0.05) fecal chromium contents.(AU)

Objetivou-se avaliar combinações entre técnicas de digestão ácida e quantificação espectrofotométrica para estimar a concentração de cromo em amostras de fezes bovinas. Foram avaliadas técnicas de digestão baseadas na utilização de ácidos nítrico e perclórico, ácidos sulfúrico e perclórico e ácido fosfórico. A quantificação da concentração de cromo nas soluções foi realizada por colorimetria e por espectrofotometria de absorção atômica (EAA). Na quantificação por EAA, foi avaliada a adição de cloreto de cálcio como agente de liberação. Amostras-padrão contendo quantidades conhecidas de cromo foram produzidas (0, 2, 4, 6, 8 e 10g de cromo por kg de fezes) utilizando-se fezes bovinas obtidas de três animais diferentes, para avaliar a acurácia das diferentes técnicas. A acurácia foi avaliada pelo ajustamento de modelo de regressão linear simples dos valores estimados sobre os valores reais de cromo nas amostras-padrão. Independentemente da técnica de digestão ácida, as estimativas da concentração de cromo nas amostras-padrão obtidas por colorimetria não foram acuradas (P<0,05). Considerando-se a quantificação de cromo por EAA, as técnicas de digestão baseadas nos ácidos nítrico e perclórico e nos ácidos sulfúrico e perclórico promoveram completa recuperação de cromo (P>0,05). A utilização da técnica de digestão em ácido fosfórico promoveu recuperação incompleta do cromo fecal (P<0,05). Posteriormente, as técnicas de digestão em ácidos nítrico e perclórico e em ácidos sulfúrico e perclórico, ambas avaliadas por EAA, foram comparadas utilizando-se 84 amostras de fezes bovinas. Os resultados indicam que aquelas combinações de técnicas promovem resultados similares (P>0,05) da concentração fecal de cromo.(AU)

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The aim of this study was to measure changes in biochemical markers in the peripartum period of primiparous Holstein cows diagnosed with subclinical and clinical mastitis. In this study, 37 dairy cows were monitored daily during milking until 60 days postpartum and were categorized according to the occurrence of clinical mastitis (group mastitis (GM), n = 9) or subclinical mastitis (group subclinical mastitis (GSUB), n = 10) or absence of symptoms (control group (CG), n = 18). Blood samples were collected weekly from -30 to 60 days from calving. Samples were grouped for prepartum (-30 to 0 days from calving), early postpartum (0 to 30 days from calving), and late postpartum (30 to 60 days from calving) periods. Prepartum serum non-esterified fatty acid (NEFA) concentration was higher in GM than in CG (P < 0.01). In addition, CG had higher prepartum serum glucose concentration than GM (P = 0.03). In the early postpartum period, aspartate aminotransferase (AST) activity was lower in CG than in GSUB (P < 0.05), and in the late postpartum period, AST activity was lower in CG than GSUB and GM (P = 0.01). Somatic cell count was higher during the early and late postpartum periods for GM and GSUB when compared to CG (P < 0.01). In this study, primiparous cows with low glucose and higher NEFA in the prepartum were more susceptible for mastitis in the early postpartum, probably due to low immune function associated to a more negative energy balance. In sum, increased prepartum serum NEFA concentration and decreased glucose in primiparous cows were associated with clinical mastitis incidence in the postpartum period.

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The aim of this study was to evaluate daily weight gain (DWG), total dry matter (DM) intake, rumen degradability of forage, and urinary excretion of mimosine metabolites by hair sheep in a silvopastoral system with high densities of Leucaena leucocephala. A completely randomized design was carried out with two treatments: treatment 1 (T1) silvopastoral system with leucaena at a density of 35,000 plants/ha and treatment 2 (T2), leucaena at a density of 55,000 plants/ha. Leucaena was associated with tropical grasses Panicum maximum and Cynodon nlemfluensis. Twenty-four male Pelibuey lambs of 23.2 ± 3.4 kg live weight (LW) were used (12 lambs per treatment). Results showed differences (P < 0.05) in DWG of T1 (106.41 ± 11.66 g(-1) sheep(-1)) with respect to that of T2 (81.33 ± 11.81 g(-1) sheep). Voluntary intake was higher in lambs from T1 (83.81 ± 04.07 g DM/kg LW(0.75)) with respect to that from T2 (71.67 ± 8.12 g DM/kg LW(0.75)). There was a difference in color of urine between sheep of T1 and T2, the latter giving positive results for the presence of metabolites derived from mimosine (3-4 dihydroxypyridine and 2-3 dihydroxy pyridone). Rumen degradability of DM of L. leucocephala was higher (P < 0.05) compared to that of P. maximum and C. nlemfluensis (72.94 ± 0.40 vs. 67.06 ± 1.50 and 63.25 ± 1.51 %, respectively). It is concluded that grazing at high densities of L. leucocephala affects daily weight gain of hair sheep, possibly due to ingestion of high amounts of mimosine which may exert an adverse effect on voluntary intake.

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The objective of this research was to use a model of unilateral and bilateral occlusion of the ductus deferens in the dog to study the use of alkaline phosphatase (AP) as an indicator of tubular patency. Seven healthy cross bred dogs weighing 10-15 kg BW with normal spermiogram and AP concentrations in semen were used. From each dog, three semen samples were obtained before (intact) and after right (unilateral) and left (bilateral) vasectomy. The AP concentrations were measured in duplicates by a colorimetric method in each of the three fractions (first, second (sperm-rich), third) of each ejaculate. In addition, a macroscopic and microscopic evaluation of each ejaculate was carried out to assure its quality. Data were analysed by least squares analysis of variance using SAS(R). In intact and unilateral vasectomized dogs, 96.6% of AP measured in semen corresponded to the second sperm-rich fraction whereas 1.53 and 1.83% corresponded to the first and third fractions respectively. Total AP concentrations (first and second and third fraction) in vasectomized dogs were lower than in intact animals (19.857 vs 2284.431 +/- 4.347 UAL; p < 0.001). AP concentrations were much lower in bilateral than in unilateral vasectomized dogs (142 vs 39.572 +/- 4.347 UL, p < 0.001). In summary, AP concentrations in semen can be used as an early indicator of unilateral or bilateral lack of patency of the epididymal and deferent ducts in the dog.

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Eighty-nine healthy dogs (44 males, 45 females) of different breeds, 1-12 years of age, living under varied feeding and environmental conditions, were sampled to evaluate a reference interval for serum fructosamine using a nitroblue tetrazolium photocolorimetric method. The analytical assay was evaluated by calculation of within-run and between-day variations. The results were approximately normally distributed and the calculated reference interval was 192.6-357.4 mumol/L (mean 275.0 mumol/ L, standard deviation 41.2 mumol/L). No significant differences attributable to sex or age were observed. This reference interval is wider than those previously reported in less heterogeneous groups of dogs and in those from other geographical zones. The fructosamine values in serum from 3 diabetic dogs all exceeded the upper limit of the reference interval.

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Se tomaron 3 muestras de tres tipos de alimentos para pollo de engorda (iniciador, desarrollo y finalizador) de 4 marcas disponibles en el valle de México (Purina, La Hacienda, Malta y Flagasa) para cuantificar fuerazolidona y nitrofurazona mediante una técnica colorimétrica. Las concentraciones se graficaron, asimismo se sujetaron a un análisis estadístico considerando: marca comercial, tipo de alimento y compuesto. Los resultados del análisis mostraron que los nitrofuranos son usados por diferentes fabricantes de alimento comercial para pollo de engorda, pero no lo indican en las etiquetas de sus productos, ni mencionan las concentraciones que manejan, aunque ninguno de los alimentos analizados superó las dosis terapéuticas recomendadas. El contenido promedio más alto de furazolidona fue de 249.84 ppm (marca Purina tipo indicador) superando el nivel máximo permitido por la Food and Drug Administration de Estados Unidos de América que de 200 ppm en alimento para pollo de engorda. Los niveles de nitrofurazona detectados no superaron la dosis terapéutica pero sí el máximo permitido 50 ppm (Purina iniciador, La Hacienda iniciador y Malta finalizador). De acuerdo al tipo de alimento, se encontró que la concentración más elevada corresponde al alimento de iniciación. Los resultados mostraron que Purina es la marca que utiliza mayores concentraciones de nitrofuranos en sus formulaciones. La sobredosis que puede causar el efecto nocivo de los nitrofuranos es factible cuando los niveles añadidos a los del granjero se le suman los del fabricante. Se encontró diferencia estadística del contenido de nitrofurano por marca, tipo de alimento y compuesto (P<0.05)

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