Abstract Characterizing growth in livestock is important when making management, marketing and genetic improvement decisions. Nonlinear models were tested to identify those with the best fit for growth curves in seven sheep breeds [Blackbelly (n= 19,084); Pelibuey (n= 39,025); Dorper (n= 35,814); Katahdin (n= 74,154); Suffolk (n= 10,267); Hampshire (n= 7,561); and Rambouillet (n= 7,384)]. Using breed registry databases, live weight was assessed from birth to 230 d of age. The SAS program was applied to test six nonlinear models: Brody, Verhulst, von Bertalanffy, Gompertz, Mitscherlich and logistic. The criteria for selecting the best-fit model were the average prediction error; the prediction error variance; the Durbin-Watson statistic; the coefficient of determination; the root-mean-square error; and the Akaike and Bayesian information criteria. For the Hampshire, Pelibuey and Suffolk breeds the best-fit model was the von Bertalanffy, with a sigmoid curve and an inflection point age between 40 and 57 d. For the Katahdin, Blackbelly, Dorper and Rambouillet breeds the best-fit models were the Brody and Mitscherlich models, with a continuous growth curve, no inflection point and constant growth rate. Marked differences were observed in adult weight between breeds, with average values (kg) of 44.6 for Blackbelly, 49.2 for Rambouillet, 52.9 for Pelibuey, 55.6 for Hampshire, 60.2 for Katahdin, 64.7 for Suffolk and 65.2 for Dorper; values tended to be highest in the Brody and Mitscherlich models, and lowest in the logistic and Verhulst models.

Resumen Caracterizar el crecimiento ayuda en la toma de decisiones de manejo, comercialización y mejoramiento genético. El objetivo fue identificar un modelo no lineal (MNL) para describir la curva de crecimiento en borregas de registro a través de siete razas. Se evaluó el peso vivo, desde el nacimiento hasta los 230 d de edad, de las razas Blackbelly (BB; n= 19,084), Pelibuey (PE; n= 39,025), Dorper (DR; n= 35,814), Katahdin (KT; n= 74,154), Suffolk (SF; n= 10,267), Hampshire (HS; n= 7561) y Rambouillet (RB; n= 7,384). Se evaluaron los MNL: Brody (BRO), Verhulst (VER), Von Bertalanffy (VBE), Gompertz (GOM), Mitscherlich (MIT) y Logístico (LOG). Los análisis se realizaron con el software SAS. Los criterios para seleccionar el modelo con mejor ajuste fueron: error de predicción promedio, varianza del error de predicción, estadístico Durbin-Watson, coeficiente de determinación, raíz del cuadrado medio del error, criterios de información Akaike y Bayesiano. Para HS, PE y SF, el mejor modelo fue VBE, con una curva sigmoide y edad al punto de inflexión entre 40 y 57 d. Los modelos BRO y MIT tuvieron el mejor ajuste para KT, BB, DR y RB, con una curva continua, sin punto de inflexión y tasa de crecimiento constante. Para peso adulto se observaron marcadas diferencias, con valores promedio (kg) de 44.6 en BB, 49.2 en RB, 52.9 en PE, 55.6 en HS, 60.2 en KT, 64.7 en SF y 65.2 en DR; con la tendencia de valores mayores para los modelos BRO y MIT, y los menores para LOG y VER.

Abstract: The objective was to evaluate the botanical composition and nutritional value in the diet of bovine cattle in areas invaded by natal grass [Melinis repens (Willd.) Zizka]. The research was conducted at the Salinas Ranch, in the municipality of Satevó, Chihuahua, in a brush grassland. Botanical composition of the area was determined by the line-point intercept method. Sampling was conducted from August 2013 to February 2014. The botanical composition of the diet (microhistological technique) and the nutritional value were determined using two esophageal-fistulated Hereford/Angus heifers (350 ± 5 kg). The data were subjected to a variance analysis, and the chemical composition of the diet was fitted using the PROC MIXED procedure of SAS to a mixed model. The average available forage during the four phenological stages was 1,279 kg DM ha-1, with a presence of 87.5 % natal grass (1,119.13 kg DM ha-1). The highest preference indexes were for Aristida divaricata (8.43) and Croton pottsii (12.95) during the growing stage; whereas the least preferred species was Melinis repens (0.33 to 0.41). The highest crude protein content was observed during the growing (13.23 %) and flowering stages (10.71 %). During this study the best quality of the diet was determined during the growing and flowering stages and was mainly composed of Melinis repens during four stages.

Resumen: Se evaluó la composición botánica y el valor nutricional de la dieta de ganado bovino en áreas invadidas por pasto rosado [Melinis repens (Willd.) Zizka]. La investigación se realizó en el Rancho Salinas, municipio de Satevó, Chihuahua, en un pastizal amacollado arbosufrutescente. La composición botánica del área se determinó por el método de línea de puntos. Los muestreos se realizaron de agosto de 2013 a febrero de 2014 y se utilizaron dos vaquillas fistuladas del esófago de la cruza Hereford-Angus de 350 ± 5 kg. La composición botánica de la dieta se obtuvo mediante la técnica microhistológica y su valor nutricional por análisis bromatológico. Los datos se sometieron a un análisis de varianza; los datos de calidad de la dieta se ajustaron a un modelo mixto mediante el procedimiento PROC MIXED del SAS. El promedio de forraje disponible durante las cuatro etapas fenológicas fue de 1,279 kg MS ha-1, con presencia del pasto rosado del 87.5 % (1,119.13 kg MS ha-1). La dieta seleccionada por el ganado bovino estuvo compuesta por 74 % de gramíneas, 19 % de arbustivas y 7 % de herbáceas. Las especies preferidas fueron Aristida divaricata (8.43) y Croton pottsii (12.95) durante la etapa de crecimiento; el menor índice de preferencia fue para Melinis repens (0.33 a 0.41). El mayor contenido de proteína cruda se obtuvo durante las etapas de crecimiento (13.23 %) y floración (10.71 %). La mejor calidad de la dieta se presentó durante las etapas de crecimiento y floración, y estuvo compuesta principalmente por Melinis repens en las cuatro etapas.

Abstract: In Lidia cattle breed, the selection is based on the performance of the bull during the fighting. Head position (HP) and hands (PH), course of the bull (CB) and finish of the onslaught (FO), define the performance of the bull, and can be implemented as selection criteria. The objective was to estimate heritability (h2) and genetic correlation (rg) for HP, PH, CB and FO; and building two selection indexes: IS1 with relative values of factorial analysis, IS2 by relative values from the standard deviation of each trait. The response to selection (RS) and accuracy (AC) were calculated. The number of observations (average ± standard deviation) value for HP, PH, CB and FO were 984 (5.46 ± 1.4), 978 (2.93 ± 1.1), 981 (3.15 ± 0.7) and 785 (2.88 ± 1.1), respectively; with scales of one to seven for HP, and one to five for the rest of the variables. For h2 and rg a multivariate analysis was performed with MTDFREML software. The h2 was of 0.20 ± 0.06, 0.15 ± 0.05, 0.13 ± 0.03 y 0.17 ± 0.05 for HP, CB, PH y FO, respectively. All rg were positive, from 0.57 to 0.94, with average value of 0.753. IS1 = 0.068*HP + 0.048*CB - 0.012*PH + 0.088*FO; with AC of 0.46 and RS of 0.325. IS2 = 0.231*HP + 0.249*CB - 0.038*PH + 0.298*FO; with AC of 0.45 and RS of 1.15.

Resumen: En la ganadería de lidia, la selección está en función del desempeño del toro durante la lidia. Posición de la cabeza (PC) y de las manos (PM), recorrido del toro (RE) y modo de finalizar (FI) la embestida define el desempeño del toro, y pueden ser considerados como criterios de selección. El objetivo fue estimar heredabilidades (h2) y correlaciones genéticas (rg) para PC, PM, FI y RE; y construir dos índices de selección: IS1 con valores relativos de un análisis factorial, IS2 con valores relativos a partir de la desviación estándar de cada rasgo. Se calculó la respuesta a la selección (RS) y exactitud (EX) de cada IS. El número de observaciones (valor promedio ± desviación estándar) para PC, PM, RE y FI fue 984 (5.46 ± 1.4), 978 (2.93 ± 1.1), 981 (3.15 ± 0.7) y 785 (2.88 ± 1.1), respectivamente; con escalas de uno a siete para PC, y de uno a cinco para el resto de las variables. Para h2 y rg se realizó un análisis multivariado con el software MTDFREML. La h2 fue de 0.20 ± 0.06, 0.15 ± 0.05, 0.13 ± 0.03 y 0.17 ± 0.05 para PC, RE, PM y FI, respectivamente; todas las rg fueron positivas, de 0.57 a 0.94, con valor promedio de 0.753. IS1 = 0.068*PC + 0.048*RE - 0.012*PM + 0.088*FI; con EX de 0.46 y RS de 0.325. IS2 = 0.231*PC + 0.249*RE - 0.038*PM + 0.298*FI; con EX de 0.45 y RS de 1.15.

ABSTRACT: The objective was to characterize the growth of Cebu cattle in grazing performance tests. We used 15 990 live weight data, taken between 150 and 630 d of age, of 3 198 males with five weights each: 1) weaning weight (WW), 2) initial test weight (IW), 3) first weighing (W1), 4) second weighing (W2) and 5) final test weight (FW). Nonlinear models (NLM) were compared: Brody (BRO), Logistic (LOG), von Bertalanffy (BER) and Gompertz (GOM). Two types of analyses (ANA1, ANA2) were carried out with the SAS NLMIXED procedure: ANA1 with mixed NLM (MNLM), by including the random effect of a regression coefficient; and ANA2 with MNL, with no random effects associated with regression coefficients. The model was selected using the criteria of mean prediction error; variance of the prediction error; Durbin Watson statistic; coefficient of determination; Akaike information criterion and Bayesian criterion. The mean weights (kg) for WW, IW, W1, W2 and FW were 175.9 ± 33.4, 182.5 ± 32.1, 225.8 ± 49.6, 266.8 ± 61.9 and 340.3 ± 68.1, respectively. Analyses with MNLM (ANA1) presented better results, with LOG being the best fit, followed by GOM, BER and BRO. The ANA2 results were overestimated and out of context to be associated with bovine growth; the growth curves generated with MNLM showed good predictive capacity and were based on the data generating process, which refers to the growth of Cebu cattle.

RESUMEN: El objetivo fue caracterizar el crecimiento de bovinos Cebú en pruebas de comportamiento en pastoreo. Se utilizaron 15 990 datos de peso vivo, tomados entre 150 y 630 d de edad, de 3 198 machos con cinco pesadas cada uno: 1) peso al destete (PD), 2) peso inicio de prueba (PI), 3) primera pesada (P1), 4) segunda pesada (P2) y 5) peso final de prueba (PF). Se contrastaron los modelos no lineales (MNL): Brody (BRO), Logístico (LOG), von Bertalanffy (BER) y Gompertz (GOM); en dos tipos de análisis (ANA1, ANA2) con NLMIXED de SAS. ANA1, con MNL mixtos (MNLM), al incluir el efecto aleatorio de un coeficiente de regresión; y ANA2 con MNL, sin efectos aleatorios asociados a coeficientes de regresión. La selección del modelo se realizó con los criterios error de predicción promedio; varianza del error de predicción; estadístico Durbin Watson; coeficiente de determinación; criterio de información Akaike y criterio Bayesiano. Los pesos promedio (kg) ajustados al PD, PI, P1, P2 y PF fueron 175.9 ± 33.4, 182.5 ± 32.1, 225.8 ± 49.6, 266.8 ± 61.9 y 340.3 ± 68.1, respectivamente. Los análisis con MNLM (ANA1) presentaron mejores resultados, siendo el LOG el que presentó mejor ajuste, seguido de GOM, BER y BRO. Los resultados del ANA2 fueron sobre estimados y fuera de contexto para asociarse al crecimiento de bovinos; las curvas de crecimiento generadas con MNLM presentaron buena capacidad predictiva y estuvieron en función del proceso generador de los datos, que se refiere al crecimiento del ganado Cebú.

ABSTRACT The objective of this research was to evaluate the productivity of beef in confinement in Mexico, through criteria of efficiency, effectiveness, quality and economy, in five entities (Nuevo Leon, Tamaulipas, Coahuila, Sonora and Baja California); considering five scales of production (3,000, 5,000, 6,000, 7,000 and 7,500 bovines completed per cycle). The average initial live weight was 267.00 ± 35.99 kg and 470 ± 11.73 kg. The average production cycle was 136 ± 22 d and 2.67 ± 0.34 cycles per year. Efficiency was 7.84 ± 1.39 kg feed/kg and 61.20 ± 0.84 % of carcass yield, efficiency 99.55 ± 0.26 %, 100 % quality and economy 3.36 ± 1.89 $/kg of net income. The benefit-cost ratio was 1.08 ± 0.03, with a marginal investment average of 17,815.98 ± 4,795.81 Mexican pesos per bovine. The conclusion is that the economic activity presents an average productivity of 63.50 ± 15.20 %.

RESUMEN El objetivo de esta investigación fue evaluar la productividad de carne de bovino en confinamiento estabulado en México, a través de criterios de eficiencia, eficacia, calidad y economía, en cinco entidades (Nuevo León, Tamaulipas, Coahuila, Sonora y Baja California); considerando cinco escalas de producción (desde 3,000 a 7,000 cabezas finalizadas por ciclo). El peso vivo inicial promedio fue 267.00 ± 35.99 kg y final 470 ± 11.73 kg. El ciclo productivo promedio fue de 136 ± 22 días y 2.67 ± 0.34 ciclos por año. La eficiencia fue de 7.84 ± 1.39 kg alimento/kg y 61.20 ± 0.84 % de carne de rendimiento en canal, eficacia 99.55 ± 0.26 %, calidad 100 % y economía 3.36 ± 1.89 $/kg de ingreso neto. La relación beneficio-costo fue de 1.08 ± 0.03, con una inversión marginal promedio de 17,815.98 ± 4,795.81 pesos por cabeza. La conclusión es que la actividad económica presenta una productividad promedio de 63.50 ± 15.20 %.

ABSTRACT The objective was to evaluate the effect of three levels of cull pinto beans (CPB; Phaseolus vulgaris) on ruminal fermentation, kinetics, and nutrient digestibility in hair lambs. Six cannulated lambs averaging 56.6±3.8 kg were used and were randomly assigned to one of three treatments. Treatments were: 0.0 kg kg−1 of CPB in the supplement (control); 0.25 kg kg−1 of CPB in the supplement (CB25); and 0.40 kg kg−1 of CPB in the supplement (CB40). Dry matter intake, ruminal pH, NH3, and volatile fatty acid (VFA) concentration, methane production, Kp (passage rate), MRT (mean retention time), and digestibility of dry matter, crude protein, and neutral detergent fiber were evaluated. Data were analyzed in a Latin square design, repeated in line, by MIXED procedure of SAS. Estimates used for Kp and MRT were obtained by a non-linear regression model (PROC NLIN). Dry matter intake was reduced by supplementation of CPB. No differences were found in ruminal pH or ruminal NH3. During the trial, differences were found for ruminal VFA concentration (mM), which were greater for the CB25 group. The propionate:acetate ratio was greater for the CB40 treatment. Methane production (mM/m) differed among treatments, but it was the greatest for the CB40 group. Passage rate (kg kg−1/h) and MRT (h) were similar among treatments and the digestibility (kg kg−1) of dry matter, crude protein, and neutral detergent fiber was not different among treatments. The inclusion of 0.25 kg kg−1 of CPB in the diet of hair lambs allows for appropriate nutrient digestion without affecting Kp and MRT and increases the molar proportion of the ability of VFA to maintain acetate:propionate ratio without increasing methane production.

ABSTRACT The objective was to evaluate the effect of cull pinto beans (CPB) (Phaseolus vulgaris) on performance of feedlot lambs. Seventy-two crossbred hair-breed lambs (Dorper × Pelibuey and Kathadin × Pelibuey) were used (75±6 days old and 18.7±3.89 kg of initial body weight). Animals were fed twice daily. Diets consisted of 20% alfalfa hay and 80% concentrate based on ground sorghum grain and were formulated to contain 17.9% crude protein and 2.60 Mcal/kg metabolizable energy. Treatments were (dry matter basis): no CPB (0%), 10% CPB, and 20% CPB. Lambs were blocked by body weight and treatments and arranged in a 2 × 3 arrangement of treatments. Body weights were recorded initially and subsequently at 14-day intervals for a total 70 number of days. Dry matter intake was recorded daily. Apparent dry matter digestibility was predicted using insoluble acid detergent fiber. Data were analyzed as a randomized complete block design. Final body weight and average daily gain decreased linearly with increasing CPB level and were greater for males than females. A level × gender interaction was observed for dry matter and crude protein digestibility. Data for hot carcass weight and cold carcass weight decreased linearly as CPB level increased and were greater for males. Carcass yield, longissimus muscle area, and dressing percentage were greater for males. Dressing percentage quadratically increased as CPB level increased. Cull pinto beans are a suitable ingredient for feedlot hair-breed lambs, but the inclusion of more than 10% of CPB level decreases animal performance.

Abstract: The aim of this study was to estimate genetic parameters for mature weight (MW) and growth rate (GR) derived from the nonlinear Brody model, and analyze the possible genetic relationships between these variables and weaning weight (WW). The information analyzed was MW (kg; n = 994), GR (kg kg-1 month-1, n = 994), and WW adjusted to 240 d (kg; n = 1506); the mean values and standard deviation (±) for MW, GR and WW were 419.1 ± 94.4, 0.0081 ± 0.0039 and 206.8 ± 34.1, respectively; the pedigree was composed of 2504 records. A multivariate analysis was performed (MW, GR and WW) from a mixed model that included as fixed effects the contemporary groups and the covariate age of the cow at calving (linear and quadratic), and as random ones the direct and maternal, maternal permanent environment, and residual genetic effects. Direct and maternal heritability, as well as the genetic correlations between direct (r aa ), maternal (r mm ), and direct with maternal effects (r am ) were estimated. The varied from 0.18 to 0.30, and the from 0.07 to 0.39, indicating that there could be a response to the selection in MW and GR. All genetic correlations were positive in an interval of 0.09 to 0.87, except the r aa between MG and GR (-0.57), this genetic antagonism indicates that individuals with high growth rates do not have the highest mature weight.

Resumen: El objetivo del presente estudio fue estimar parámetros genéticos para el peso adulto (PEA) y tasa de crecimiento (TAC) de bovinos Tropicarne, derivados del modelo no lineal de Brody; así como analizar las posibles relaciones genéticas de estas variables con el peso al destete (PD). Se analizaron 994 datos de PEA (kg) y de TAC (kg-1 mes-1) y 1 506 datos de PD ajustado a 240 d. Los valores promedio y la desviación estándar (±) para PEA, TAC y PD (kg) fueron de 419.1 ± 94.4, 0.0081 ± 0.0039 y 206.8 ± 34.1, respectivamente. El pedigrí se integró por 2 504 individuos. Se realizó un análisis multivariado, a partir de un modelo mixto que consideró como efectos fijos los grupos contemporáneos y la covariable edad de la vaca al parto (lineal y cuadrático); y como aleatorios los efectos genéticos directos y maternos, maternos de ambiente permanente y residuales. Se estimó la heredabilidad directa y materna , las correlaciones genéticas entre los efectos directos (raa), los maternos (rmm), y los directos con maternos (ram). Las oscilaron de 0.18 a 0.30, y las de 0.07 a 0.39; lo cual indica una probable respuesta a la selección en PEA y TAC. Todas las correlaciones genéticas fueron positivas en un intervalo de 0.09 a 0.87, con excepción de r aa entre PEA y TAC (-0.57); este antagonismo genético indica que los individuos con tasas altas de crecimiento no son los de mayor peso adulto.

Abstract: In 2011 it was presented one of the most devastating droughts in northern Mexico that seriously affected the activities of the productive sector. The aim of this study was to predict the next event of drought in the northwest region of the state of Chihuahua, Mexico. Information of 40 years was used in four weather stations. The ARIMA models with nine years seasonality were used, and artificial neural networks with 50 neurons and 24 delays were used. Precipitation from 2000 to 2012 was simulated and predicted from 2013 to 2024. For the Abraham Gonzalez station is forecasted for 2019 and 2022 less than 200 mm precipitation will occur. While in the Bachíniva station is forecasted for 2019 about 140 mm precipitation. While at the station Cuauhtemoc is forecasted for 2020 a rainfall of about 200 mm. While in Namiquipa station, a precipitation of around 160 mm is forecasted for 2018. It concludes that between 2018 and 2019, a between moderately and severe drought will occur in the northwestern region of the state of Chihuahua.

Resumen: En el 2011 se presentó una de las sequías más devastadoras en el norte de México que afectó de forma negativa las actividades del sector productivo. Por lo anterior, el objetivo del presente trabajo fue pronosticar el próximo evento de sequía en el noroeste del estado de Chihuahua, México. Se utilizó información de 40 años de cuatro estaciones meteorológicas. Se empleó el modelo ARIMA con estacionalidad de nueve años, y redes neuronales artificiales con 50 neuronas y 24 retardos. Se simuló la precipitación del 2000 al 2012 y se pronosticó del 2013 al 2024. Para la estación Abraham González se pronostica que para el 2019 y 2022 se presentará una precipitación menor a 200 mm. En tanto que en la estación Bachíniva para el 2019 se presentará una precipitación de 140 mm. Mientras que en la estación Cuauhtémoc se pronostica que para el 2020 se presente una precipitación de alrededor de 200 mm. Por su parte en la estación Namiquipa, se pronostica una precipitación cercana a los 160 mm para el 2018. Se concluye que entre el 2018 y 2019, ocurrirá una sequía de moderada a severa en la región noroeste del estado de Chihuahua.

ABSTRACT In order to find the best sideoats grama variety (Bouteloua curtipendula) for rehabilitation, five commercial varieties were evaluated: Niner (Ni), Vaughn (Va), El Reno (Re), Kansas-6107 (K-07) and Kansas-6113 (K-13). Two tests were carried under a greenhouse during 77 d. In the first test the variables measured were seedling emergence (% EM), plant density, plant height, dry matter at first cut, height of regrowth, regrowth dry matter and survival (% SV). In the second test, the variables evaluated were root length, aerial biomass and the ratio of root-aerial biomass. Data analyses were carried out by principal components and cluster analysis by using the Ward method and orthogonal contrasts with MANOVA under SAS. The scatter plots and dendogram were obtained with MINITAB. The first two components explained 77 % of the variation. Differences (P<0.05) occurred in most of the variables, only % EM and % SV had no significance. The CP 2 presented correlation (r= 85.1 %. P<0.0001) with % SV. Cluster analysis integrated three groups (G): G-1 (Ni and Va), G-II (Re) and G-III (K-07 and K-13). According to the multivariate analysis, the varieties were classified by productive importance: Va and Ni showed no difference, however, they were higher (P<0.05) than the other varieties. The cultivars Va and Ni had the highest potential for forage production, Re showed an intermediate performance and the Kansas varieties were the least productive.

RESUMEN Con el fin de identificar la mejor variedad de banderita (Bouteloua curtipendula) con el mayor potencial de establecimiento y productividad, se evaluaron cinco variedades comerciales usadas en rehabilitación de pastizales: Niner (Ni), Vaughn (Va), El Reno (Re), Kansas-6107 (K-07) y Kansas-6113 (K-13). Se realizaron dos pruebas bajo condiciones de invernadero con una duración de 77 días. Las variables evaluadas en la prueba uno fueron: emergencia (% EM), densidad de plantas, altura de planta, materia seca del primer corte, altura de rebrote, materia seca de rebrote y supervivencia (% SV). Las variables evaluadas en la prueba dos fueron: longitud de raíz, altura de biomasa aérea y proporción radícula-biomasa aérea. Los datos se analizaron mediante componentes principales, conglomerados y un MANOVA en SAS. Las gráficas de dispersión y dendograma se obtuvieron con MINITAB. Los dos primeros componentes explicaron el 77 % de la variación. Se presentaron diferencias (P<0.05) en la mayoría de las variables, solo % EM y % SV no tuvieron significancia. El CP 2 presentó correlación (r= 85.1 %; P<0.0001) con % SV. El análisis de conglomerados integró tres grupos (G): G-1 (Ni y Va) G-II (Re) y G-III (K-07 y K-13). De acuerdo al análisis multivariado, se clasificaron las variedades por importancia productiva: Ni y Va no presentaron diferencia, pero éstas fueron superiores (P<0.05) al resto de las variedades. Las variedades Vaughn y Niner presentaron el más alto potencial forrajero, El Reno presentó un comportamiento intermedio, y las variedades Kansas-6107 y Kansas-6113 fueron las de menor productividad.

Abstract: This investigation analyzes income distribution inequality of the agricultural producers of Chihuahua, Mexico. This was across the Gini Coefficient (GC). Net Income (NI) was used, as well as, government transferences and the value of assets of the agricultural producers. The producers were stratified in nine groups considering the asset value and marginality grade. The GC of NI for farmers was 74%, agriculture 81%, livestock 70%, government transferences 71% and assets 75%. 50% of the producers with high assets accumulated 54% of agricultural income, while 67% with low marginalization 71%. For livestock producers, 96% of the NI focused on producers with high assets and 70% in producers with low marginalization.

Resumen: Esta investigación analiza la desigualdad en el ingreso de los productores agropecuarios Chihuahua, México. Esto se realizó mediante el cálculo del Coeficiente de Gini (CG). Se utilizó el Ingreso Neto (IN), así como transferencias de gobierno y valor de los activos. Los productores se estratificaron en nueve grupos considerando el valor de los activos y el grado de marginación. El CG del IN fue 74% para los productores agropecuarios, agrícolas 81%, pecuarios 70%, transferencias de gobierno 71% y activos 75%. El 50% de los productores con activos altos acumuló 54% del ingreso agropecuario, mientras que 67% con baja marginación el 71%. Para productores pecuarios, el 96% del IN se concentró en productores con activos altos y 70% en productores con baja marginación.

The aim of this study was to evaluate and compare the percentage content of fatty acids (FA) of 54 rainbow trout fresh and frozen fillets. Frozen fillets were stored at -15ºC for 45 and 90 days. Saturated (SFA), monounsaturated (MUFA), polyunsaturated (PUFA), omega-6 (n-6) and omega-3 (n-3) fatty acids were determined by gas chromatograph coupled to mass spectrometry. The results indicated that during frozen storage, SFA and MUFA content increased by 32.63 and 9.25%, respectively, while PUFA content decreased by 25.3%, n-6 by 12.4% and n-3 by 32.55%. These changes were more significant (P ≤ 0.05) during the first 45 d of storage. It was concluded that the frozen storage had a negative impact on meat quality of rainbow trout due to the reduction of PUFA, n-3/n-6, polyene index and PUFA/ SFA and the increase of the SFA, and atherogenic and thrombogenic indexes, which meant a substantial loss of nutritional value in the fillets of rainbow trout.

Pedigree analysis is an important tool to describe the genetic variability and its evolution through generations. The objective was to estimate genetic distances and to analyze the possible genetic differentiation through Mexican fighting bull herds. The pedigree including 58826 animals from 110 herds, born from 1970 to 2010 was used. The average number of animals in a herd was 534, the range was 107 to 4552. With the Software ENDOG it was calculated the Nei genetic distances (DGNei) and the F IS and F ST statistics. Then with the DGNei and using the Software TreeView it was built a graphic representation. The F ST values ranged from 0.0001 to 0.0909, it averaged 0.0086. This value revealed that 0.86% of the genetic variance could be attributed to differences between populations, the 99.14% remaining to differences between individuals within populations. The F IS values ranged from -0.3333 to 0.0099, with average of -0.0167; these results revealed an average increase in heterozygosis of 1.67% and maximum increase of 33.3%, causing a possible disequilibrium Hardy-Weinberg. The DGNei ranged from 0.0009 to 0.0859, with an average of 0.0217; the graphical representation, the arrangement of herds showed no differentiation in groups.

El análisis del pedigrí es una herramienta importante para describir la variabilidad genética y su evolución a través de las generaciones. Con el objetivo de estimar distancias genéticas y analizar la posible variabilidad genética a través de ganaderías de lidia mexicanas, se editó el pedigrí con 58826 individuos de 110 ganaderías, nacidos de 1970 a 2010. El promedio de individuos por ganadería fue 534, con rango de 107 a 4552 individuos. Con el programa ENDOG se estimaron las distancias genéticas de Nei (DGNei), así como los estadísticos F IS y F ST; posteriormente, con las DGNei y el programa TreeView se construyó una representación gráfica. Las estimaciones de F ST fluctuaron de 0.0001 a 0.0909, el promedio fue 0.0086. El valor promedio de F ST reveló que 0.86% de la varianza genética se puede atribuir a diferencias entre poblaciones y el 99.14% restante a diferencias entre individuos dentro de poblaciones. Las estimaciones de F IS oscilaron entre -0.3333 y 0.0099, con un promedio general de -0.0167; estos resultados revelaron un incremento promedio de heterocigosis de 1.67% y máximos de 33.3%, repercutiendo en un posible desequilibrio Hardy-Weinberg. Las DGNei fluctuaron de 0.0009 a 0.0859, con una estimación promedio de 0.0217; en la representación gráfica, el acomodo de las ganaderías no presentó una diferenciación en grupos.