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The main objective was to develop equations to predict body weight (BW) using heart girth (HG) in Pelibuey ewes. A second objective was to evaluate this model for precision using an independent dataset. For model develop a data set composed by 366, 2-3-yr-old, non-pregnant and non-lactating ewes; with a mean BW of 45.7 ± 9.16 kg and HG of 87.55 ± 7.93 cm was used. A linear equation was fitted: BW=-47.97 (±2.01) + 1.07 (±0.02)×HG (r 2 = 0.86, Root mean square error (RMSE)= 3.46, y n= 366). A second data set composed by 67 animals, with similar characteristics (BW of 38.25 ± 8.62 kg and HG of 80.37 ± 7.03 cm) was used to evaluate the developed equations. For the evaluation, the relationship between observed and predicted values of BW by linear regression, the mean squared error of prediction (MSEP) and root MSEP (RMSEP), and concordance correlation coefficient analysis were used. The proposed equation was highly precise (R 2 =0.913) and accurate (Cb=0.996) with a reproducibility index of 0.95. The MEF has indicated a higher efficiency of prediction with higher proportion of the total variance of the observed values been explained by the predicted data (0.91). The partition of the MSEP has indicated a very small mean bias (0.082). The systematic bias has shown that only 1.93 % of the error of prediction was associated with the slope and most of the error was explained by the random component indicating small biases with the predictions. The proposed equation accurately and precisely estimated the BW of non-pregnant and non-lactating Pelibuey ewe using HG and therefore is recommended to be used.

The present study was designed to evaluate the relationship between the body measurements (BMs) and carcass characteristics of hair sheep lambs. Twenty hours before slaughter, the shrunk body weight (SBW) and BMs were recorded. The BMs involved were height at withers (HW), rib depth (RD), body diagonal length (BDL), body length (BL), pelvic girdle length (PGL), rump depth (RuD), rump height (RH), pin-bone width (PBW), hook-bone width (HBW), abdomen width (AW), girth (GC), and abdomen circumference (AC). After slaughter, the carcasses were weighed and chilled for 24 h at 1 °C, and then were split by the dorsal midline. The left-half was dissected into total soft tissues (muscle + fat; TST) and bone (BON), which were weighed separately. The weights of viscera and organs (VIS), internal fat (IF), and offals (OFF—skin, head, feet, tail, and blood) were also recorded. The equations obtained for predicting SBW, HCW, and CCW had an r2 ranging from 0.89 to 0.99, and those for predicting the TST and BON had an r2 ranging from 0.74 to 0.91, demonstrating satisfactory accuracy. Our results indicated that use of BMs could accurately and precisely be used as a useful tool for predicting carcass characteristics of hair sheep lambs.

En el estado de Tabasco, México se pueden encontrar plantas de chile (Capsicum spp.) de forma silvestre que se diferencian por sus características morfológicas. Con el objetivo de recolectar y evaluar in situ la diversidad morfológica de chiles silvestres, de enero a septiembre de 2013 se realizó la exploración de 48 comunidades en 14 municipios del estado de Tabasco. Durante la exploración se recolectaron y tomaron datos de variables de planta, flor y fruto de 89 colectas. Se encontró la presencia de las especies C. annuum var. glabriusculum en los morfotipos ‘Amashito’, ‘Ojo de cangrejo’ y ‘Garbanzo’; y C. frutescens L. en el morfotipo ‘Pico paloma’. El análisis de componentes principales y de conglomerados con las 12 variables relevantes, diferenciaron a las colectas en dos grupos, los cuales se formaron con base en variables de fruto y de hoja. El primer grupo se formó con las 43 colectas de C. annuum var. glabriusculum que se caracterizan por tener frutos de forma redonda, corola pequeña de color blanco y una flor por nudo; el segundo grupo se formó con 46 colectas de C. frutescens L. que se caracterizan por tener frutos alargados, corola de color blanca verdosa y de dos a tres flores por nudo. Al interior de los grupos también se presentó una diferencia gradual y continua de las variables, lo que permitió formar subgrupos. En los chiles silvestres del Estado de Tabasco se encuentra diversidad morfológica, recurso genético valioso que debe conservarse.

The objective of this study was to evaluate the e ect of grazing frequencies and intensities on herbage accumulation and nutritive value of Brachiaria hybrid 36061 cv. Mulato. Grazing frequencies of 14, 21 and 28 d and intensities of 9 to 11 and 13 to 15 cm were studied under a randomized block design in a 3x2 factorial arrangement with three replicates. Herbage accumulation, morphological components, in situ digestibility (DIGDM), crude protein (CP), neutral detergent ber (NDF) and acid detergent ber (ADF) were evaluated. Annual yield distribution was 55, 28 and 16 % during the rainy, northern cold-front and dry seasons, in the rst cycle, with the highest annual accumulation of 12 310 kg DM ha−1 obtained by grazing every 28 d. The highest DIGDM and PC were obtained by grazing at an intensity of 9 to 11 cm every 14 d in all seasons. However, grazing at an intensity of 13 to 15 cm every 28 d resulted in greater forage yield with a high concentration of NDF and ADF. In conclusion, the greatest herbage accumulation, NDF and ADF were recorded by grazing of 13 to 15 cm in height every 28 d in both cycles. DIGDM and CP had high values by grazing of 9 to 11 cm every 14 d.

RESUMENEn las regiones tropicales las gramíneas representan la principal fuente de alimentación para los rumiantes, por lo que el rendimiento y la calidad forrajera son de gran interés para mitigar la baja productividad. La mayoría de los estudios en forrajes se basan en la producción de la materia seca y el valor nutritivo, sin considerar los caracteres morfogenéticos y estructurales del pasto, en la dinámica de rebrote. En Brachiaria hibrido cv mulato se estudiaron a 14, 21 y 28 días de pastoreo, y 9-11, 13-15 cm de altura residual, que se distribuyeron en un diseño de bloques al azar en arreglo factorial 3 x 2 con tres repeticiones. Se midió: acumulación de forraje, densidad poblacional de tallos, tasa de aparición y muerte de tallos, recambio de tejido foliar. La mayor acumulación del forraje fue de 2,769, 4,985, 7,033 kg de materia seca por hectárea con pastoreo ligero en lluvias. La tasa de aparición de tallos con el pastoreo severo superó en 13, 8 y 14 % al ligero en las épocas de nortes, seca y lluvias en el primer ciclo. La mayor elongación foliar se obtuvo al pastorear cada 28 días en la época de lluvias. Se concluye que durante la época de lluvias el pasto mulato presentó la mayor acumulación del forraje al cosecharse en periodos de 28 días con pastoreo ligero. La tasa de elongación y senescencia foliar mostraron los mayores valores al pastorear ligeramente la pradera cada 28 días con una densidad menor de tallos. PALABRAS CLAVE: Forraje, Brachiaria hibrido, Dinámica de tallos, Tejido foliar. ABSTRACTGrasses are the main feed source for ruminant livestock in tropical regions. Forage yield and quality are therefore extremely important for mitigating low productivity. Most studies of forage are based on dry matter production and nutritional value, and ignore grass morphogenetic and structural traits in the resprouting dynamic. Brachiaria hibrido cv. mulato was studied at 14, 21 and 28 d grazing frequencies, and 9-11 and 13-15 cm residual heights using a random block design and a 3 x 2 factorial arrangement with three replicates. Five variables were measured: forage accumulation; population stem density; stem appearance rate; stem death rate; and leaf tissue turnover. At all three frequencies, forage accumulation was highest under light grazing during the rainy season (

This study determined the effect of feeding Moringa oleifera (MO) leaf extracts to lactating ewes on the physicochemical composition of their milk and yogurt during storage (4 °C for 14 days) and the sensory acceptance of the yogurt. Over 45 days, 24 multiparous lactating Pelibuey and Katahdin ewes (two days in lactation) were randomly assigned to four groups: MO-0, basal diet (BD) + 0 mL MO; MO-20, BD + 20 mL MO; MO-40, BD + 40 mL MO; and MO-60, BD + 60 mL MO. In the milk, an increase of 6% in protein, 26% in leucine, 14% in ash, and 1% in the pH (6.71) was observed with MO-60. The density values decreased by 0.3% at a higher dose of MO compared to MO-0, while the nonfat solids (NFS) in the milk were similar between the treatments. In the yogurt, an increase of 5% in protein, 113% in leucine (MO-20), 9% in NFS, and a reduction of 2% in moisture with MO-60 was observed. The acidity reflected an inverse relationship to the pH, as did the moisture and NFS with MO-60. In conclusion, dietary supplementation with MO in lactating ewes did not have negative effects on the chemical composition of their yogurt during storage (14 days). Overall, feeding sheep with 20 mL of MO positively influenced the physicochemical composition of their milk and yogurt during storage.

The effects of an extended photoperiod (18 h light or 12 h light), using a combination of natural and artificial light sources, on the differential gene expression and growth rate of Nile tilapia Oreochromis niloticus L. were evaluated. Four groups of all males tilapia (n=10) with initial mean body weight of 102.25 g were reared in an aquaria with two replications for each treatment. The experiment was conducted during a period of 35 days, growth rate and water quality (dissolved oxygen, pH, nitrite, nitrate) were measured weekly, temperature and solar radiation were recorded daily. At the end of the experiment we used a zebrafish genome array to study differential expression over 14,900 transcripts and to test the hypotheses that an extended photoperiod stimulates growth rate and causes differential gene expression in tilapia. Fishes in the extended photoperiod group (Ep) were susceptible to show higher growth rate (GR) compared with the standard photoperiod group (Sp; P = 0.001). Food conversion efficiency in the Ep was superior than the Sp. Differential expression of genes related to transcriptional regulation for biological function was detected using zebrafish GeneChip ® (Affymetrix) microarrays, this could explain how the fish alters their metabolism as response to this phenomena.