Efectos del genotipo, tamaño de la camada y el sexo sobre las características de la canal y el perfil de ácidos grasos en corderos de pelo

The effect of the genotype (Pelibuey vs Katahdin), type of lambing (single vs. double) and sex (males vs. females) on the characteristics of the carcass and its cuts, in addition to the fatty acid profile of the loin were evaluated in 66 lambs slaughtered at weaning. The yield of the carcass and ribs were higher (P<0.05) in the Pelibuey breed. Slaughter weight, carcass weight and rib yield were higher (P<0.01) in single-born lambs, while the yield of shoulder and leg were lower (P<0.01) than in double-born lambs. The proportion of soft tissue of the different cuts was higher (P<0.05), but that of bone was lower (P< 0.05) in single-born lambs than in double-born lambs. Females had a higher (P<0.05) proportion of soft tissue and a lower proportion of bone (P<0.01) than males. The concentrations of C18:1n7 and C20:4n-6 were higher (P<0.05) in the Pelibuey breed than in the Katahdin breed, while the C22:5n-3 and C22:6n-3 were lower. The percentage of monounsaturated fatty acids was higher (P<0.05) in the meat of single-born lambs, while that of total polyunsaturated fatty acids and n-3 was higher (P<0.05) in double-born lambs. The characteristics of the carcass, the tissue composition of the commercial cuts and the fatty acid profile in hair sheep slaughtered at weaning varied more due to the type of lambing than due to the genotype or sex.El efecto del genotipo (Pelibuey vs Katahdin), tipo de parto (simple vs dobles) y sexo (machos vs. hembras) sobre las características de la canal y de sus cortes, además del perfil de ácidos grasos del lomo fueron evaluados en 66 corderos sacrificados al destete. El rendimiento de la canal y del costillar fue mayor (P<0.05) en la raza Pelibuey. El peso al sacrificio, peso de canal y rendimiento del costillar fue mayor (P<0.01) en crías de parto simple, mientras que el rendimiento de paleta y pierna fue menor (P< 0.01) que en crías de parto doble. La proporción del tejido blando de los diferentes cortes fue mayor (P<0.05), pero el de hueso fue menor (P< 0.05) en crías de parto simple que las de parto doble. Las hembras tuvieron mayor (P<0.05) proporción de tejido blando y menor proporción de hueso (P<0.01) que los machos. Las concentraciones de C18:1n7 y C20:4n-6 fueron mayores (P< 0.05) en la raza Pelibuey que, en la Katahdin, mientras que los C22:5n-3 y C22:6n-3 fueron menores. El porcentaje de ácidos grasos monoinsaturados fue mayor (P<0.05) en la carne de crías de partos simples, en tanto que el de los ácidos grasos poliinsaturados totales y n-3 fue mayor (P<0.05) en crías de partos dobles. Las características de la canal, la composición tisular de los cortes comerciales y el perfil de ácidos grasos en ovinos de pelo sacrificados al destete mostraron más cambios por el tipo de parto que por el genotipo o el sexo

Producción de forraje y composición morfológica del pasto mulato (Brachiaria híbrido 36061) sometido a diferentes regímenes de pastoreo

Three grazing frequencies (14, 21 and 28 d) and two grazing intensities (9-11 and 13-15 cm cutting height) were assessed in Mulato grass (Brachiaria hybrid 36061) in a completely randomized block design with a 3*2 factorial arrangement and three replicates. The following attributes were taken into account, herbage yield, growth rate (GR), botanic composition and leaf:stem ratio. No significant interaction (P>0.05) was found between frequency*intensity for herbage yield. Herbage yield distribution was 55, 28 and 17 % respectively for the rainy, north and dry seasons in 2007-2008, evaluation period. The highest annual herbage yield (12,310 kg DM ha-1) was recorded with 28 d grazing interval at 13-15 cm of grazing intensity. Herbage yield increased progressively when grazing frequency lengthened from 14 to 28 d (PEn Brachiaria híbrido se estudiaron tres frecuencias (14, 21 y 28 días) y dos intensidades de pastoreo (9-11 y 13-15 cm), distribuidos en un diseño de bloques al azar en arreglo factorial 3 x 2 con tres repeticiones. Se midió: acumulación de forraje, tasa de crecimiento (TC) composición botánica y relación hoja: tallo. No hubo efecto de int eracción (P>0.05) frecuencia x intensidad en la acumulación de forraje. La distribución del rendimiento fue de 55, 28 y 17 % durante las épocas de lluvias, nortes y seca, en el año 2007-2008, con la mayor acumulación anual (12,310 kg MS ha-1) al pastorear cada 28 días, con un incremento progresivo conforme aumentó el intervalo de pastoreo de 14 a 28 días (

Development and evaluation of equations to predict body weight of Pelibuey ewes using heart girth

The aim of this study was to develop and evaluate equations to predict body weight (BW) using heart girth (HG) in Pelibuey ewes. For model develop a data set composed by 366, 3-year-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 (R2 = 0.86, 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 (r2 =0.913) and accurate (Cb=0.996) with a reproducibility index of 0.95. The MEF have indicates 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 have indicated a very small mean bias (0.082). The systematic bias have 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 Pelibuey ewe using HG and therefore is recommended to be used

Production and quality of meat from hair sheep grazing on Tanzania grass and supplemented with different protein levels

Objective: To evaluate the effect of a supplementary feeding (with different crude protein (CP) levels) in the yield and growth performance and meat characteristics of hair lambs grazed on Tanzania grass. Design/Methodology/Approach: A 120-d-1 experiment was conducted; it included four treatments and seven replications in a completely randomized design. Twenty-eight hair lambs (22.6 ± 1.6 kg LW) were allowed to graze on Tanzania grass (Panicum maximum) and were provided concentrate feeds (with 10, 12, 14, and 16% crude protein). The aim was to assess the effects of the latter food on growth, carcass characteristics, and meat quality. Results: Compared with the lambs fed with 10, 12, and 14% CP, the heaviest carcasses (P&lt;0.05) were obtained from lambs fed with 16% CP. The percentage of crude protein and fat of the biceps femoris linearly increased (P&lt;0.05) as the CP percentage increased in the concentrate feed. Meat color, water retention capacity, and cutting force were not impacted by the CP percentage of the concentrate feeds. Compared with the lambs fed with 10, 12, and 14%, the lowest palmitic acid percentage and the highest oleic acid percentage were found in the meat of lambs fed with 16% CP. Study Limitations/Implications: A high area was selected to avoid excessive rain. Findings/Conclusions: Compared with the lambs fed with 10, 12, and 14% CP, the lambs grazed on Tanzania grass and supplemented with 16% CP grew more, recorded a higher carcass yield, and their meat had a better unsaturated fatty acids ratio

Luteolytic failure as the cause of low efficiency in synchronization with prostaglandins in cows under tropical grazing

Our objective was to determine the cause of the low response in the exclusive use of prostaglandin in synchronization programs in cows under tropical grazing compared to the use of progesterone (CIDR). Thirty-five cows with the presence of CL were randomly distributed: first group (GPG; n=23), synchronized with two doses of PGF2α (25 mg, Dinoprost®), with an interval of 12 days. The second group (GCIDR; n=12) synchronized with an intravaginal device (1.9 g progesterone), 2 mg estradiol benzoate and 50 mg progesterone), at day 7 a dose of PGF2α (pm) was administered and at day 8 the CIDR (am) was withdrawn. CL regression, luteolitic failure, progesterone concentration and CL size were determined. The data were subjected to normality test, then to Mann-Whitney U test or independent t student test and chi square. Finding that only 82.6% (19/23) of GPG cows at the second dose of prostaglandins have functional CL (&lt;1 ng/ml of progesterone). Obtaining only in 43.5% of the cows a regression of the CL in the GPG, vs. 91.7% in GCIDR (P=0.0001). In addition, GPG cows showed luteolytic failure of 39.1% and asynchrony of 17.4%. It is concluded, a low efficiency of prostaglandins on the synchrony and regression of CL (luteolitic failure) in cows fed under tropical grazing, attributed to the low efficiency in synchronization programs.Objective: To determine the reason for the low response to the exclusive use of prostaglandin in synchronization programs in cows under tropical grazing compared with the use of progesterone (CIDR). Design/Methodology: Thirty-five cows with CL were randomly distributed in two groups. The first group (GPG; n=23) was synchronized using two doses of PGF2α (25 mg of Dinoprost®) with a 12-day interval. The second group (GCIDR; n=12) was synchronized with an intravaginal device (1.9 g of progesterone, 2 mg of estradiol benzoate, and 50 mg of progesterone); a PGF2α (pm) dose was applied on day 7, before removing the CIDR (am) on day 8. CL regression, luteolytic failure, progesterone concentration, and CL size were determined. Data was subjected to a normality test, followed by the Mann-Whitney U test or independent Student's t-test and chi-square test. Results: Only 82.6 % (19 out of 23) of the GPG cows that received the second dose of prostaglandins have a functional CL (&lt;1 ng mL-1 of progesterone). The CL recorded a regression only in 43.5% of the cows in GPG vs. 91.7% in GCIDR (P=0.0001). In addition, GPG cows showed a luteolytic failure of 39.1% and an asynchrony of 17.4%. Conclusions: The low effectiveness of prostaglandin on the synchrony and regression of the CL (luteolytic failure) in cows fed under tropical grazing can be attributed to the low efficiency of the synchronization programs

Rendimiento y valor nutritivo del pasto mulato (Brachiaria hibrido, 36061) en respuesta al pastoreo: Performance and nutritive value of mulato grass (Hybrid brachiaria, 36061) in response to grazing

El objetivo de esta investigación fue determinar el rendimiento de materia seca (RMS), tasa de acumulación neta de forraje (TANF), y valor nutritivo del pasto mulato (VNPM), a diferente manejo de pastoreo en diferentes épocas del año. Los tratamientos se distribuyeron aleatoriamente en un diseño de bloques al azar con arreglo factorial 3 x 2, con tres repeticiones (Frecuencias: 14, 21 y 28 días; Intensidad de pastoreo: 9 a 11 y 13 a 15 cm.&nbsp; El pasto mulato presentó mayor acumulación de forraje, aparición de tallos y recambio de tejido foliar en la época de lluvias y nortes. Con pastoreo cada 28 días, a intensidad de 13-15 cm se obtuvo mayor acumulación de forraje (6732 kg MS ha-1), TANF (47 kg MS ha-1 dia-1) y altura de planta (35 cm), con una proporción de hojas y tallos de 5197 y 1473 kg MS ha-1, que propició una disminución en la relación hoja:tallo y una tasa de crecimiento foliar de 4.8 cm tallo-1 dia-1). Al ampliar el intervalo de pastoreo de 14 a 28 días, disminuyó la aparición y densidad de tallos (p&lt;0.05) y aumentó el peso de este (p&lt;0.05), en este sentido la MS digestible y el contenido de PC disminuyeron. En la época de seca no presentó síntomas de marchites y conservo un color verde en sus hojas, lo cual se observó en el crecimiento foliar. En conclusión, se debe pastorear cada 21 d a una intensidad ligera, en época de lluvias, nortes y secas cada 28 d

Dinámica de crecimiento y valor nutritivo del pasto mulato, a diferente manejo de pastoreo.

El objetivo de la investigación fue determinar el rendimiento de materia seca, tasa de acumulación neta de forraje (TANF), dinámica de tallos, peso por tallo, recambio de tejido y valor nutritivo del pasto Mulato a diferente manejo de pastoreo. Se utilizaron 18 parcelas de 12.5 x 8 m, distribuidas aleatoriamente en un diseño de bloques al azar con arreglo factorial 3 x 2 (F: 14, 21, 28 días; I: 9-11, 13-15 cm de altura). El pasto Mulato, presentó mayor acumulación de forraje, aparición de tallos y recambio de tejido foliar en la época de lluvias y nortes. En Mulato, con pastoreo cada 28 días, a intensidad de 13-15 cm se obtuvo mayor acumulación de forraje (6732 kg MS ha-1), TANF (47 kg MS ha-1 dia-1) y altura de planta (35 cm), con una proporción de hojas y tallos de 5197 y 1473 kg MS ha-1, que propició una disminución en la relación hoja:tallo y una tasa de crecimiento foliar de 4.8 cm tallo-1 dia-1). Al ampliar el intervalo de pastoreo de 14 a 28 días, disminuyó la aparición y densidad de tallos y aumentó el peso del mismo, en este sentido la MS digestible y el contenido de PC disminuyeron y aumentaron el contenido de FDN y FDA. El pasto Mulato, en época de seca no presentó síntoma de marchites y se observó crecimiento foliar en toda la época de seca. Por lo que se recomienda pastorear cada 21 días a una intensidad ligera en época de lluvias y en nortes y seca cada 28 días. _______________ REGROWTH DYNAMICS AND NUTRITIVE VALUE OF THE GRASSES MULATO UNDER DIFFERENT GRAZING MANAGEMENTS. ABSTRACT: The objetcive of this research was determine dry matter yield, net herbage accumulation rate (NHAR), tillering dynamics, tiller weight, herbage tissue turnover, and nutritive value of Mulato grasses, under different grazing managements. grass were used 18 paddocks of 12.5 x 8 m, randomness distributed in a block design with 3 x 2 factorial arrangement (F: 14, 21, 28 days); I: 9-11, 13-15 cm cut height). Mulato presented higher herbage mass accumulation, tiller appearance, and tissue turnover, in rainy and windy season. In Mulato, the highest herbage accumulation was obtained grazing every 28 days with 13-15 cm clipping height (6732 kg MS ha-1, 47 kg MS ha-1 day-1 of NHA, and 35 cm height plant, with a leaf:steam ratio of 5197 and 1473 kg MS ha-1 respectively, that caused a leaf:steam ratio decrease and a leaf growth rate of 4.8 cm tiller-1 día-1. Increasing the grazing interval from 14 to 28 days, reduced the tiller appearance and density and increased tiller weight, in this way the digestible DM and CP content decreased and NDF and ADF content increased. In this season only with Mulato was observed foliar growth in contrast, was totally dried under dry season conditions. In rainy and windy is recommended grazing with a light intensity every 21 days and every 28 days in dry season.Tesis. (Doctorado en Ciencias, Especialista en Ganadería).- Colegio de Postgraduados, 2010.Consejo Nacional de Ciencia y Tecnología (CONACYT)

Effects of temperature and salinity on inducing spawning in the eastern oyster (Crassostrea virginica) under laboratory conditions

The effectiveness of two stimuli (thermal and salinity shock) in inducing spawning in the eastern oyster Crassostrea virginica was tested under laboratory conditions. Organisms were obtained in Machona Lagoon, located in Sánchez Magallanes, Tabasco. Temperatures used were 10, 15, 20, 25 and 30 °C and the salinities were 10, 15, 20, 25 and 30 psu. The objective of this work was to determine the effects of salinity and thermal shock on spawning of C. virginica oyster. The best spawning results were obtained by using salinity shock, which induced spawning in 55% of the oysters tested, with the number of males that spawned being significantly higher than that of the females. Thermal shock was less effective with only 34% of organisms spawning and, unlike the salinity results, the number of females was higher than that of males. Temperatures of 30 oC or greater had a negative effect on spawning and was similar at a salinity of 30 psu. The optimum time for spawning was between 11 and 15 min of exposure to salinity shock, whilst for thermal shock it was between 16 and 20 min.La efectividad del choque térmico y choque de salinidad sobre el desove del ostión americano Crassostrea virginica fue llevado a cabo bajo condiciones de laboratorio. Los organismos fueron obtenidos en la laguna Machona, Sánchez Magallanes, Tabasco. Las temperaturas empleadas fueron 10, 15, 20, 25 and 30 oC y las salinidades de 10, 15, 20, 25 y 30 ups. Los mejores resultados en el desove se obtuvieron al emplear el choque de salinidad, el cual indujo el desove en 55% de los ostiones muestreados, siendo el número de machos que desovaron significativamente mayor que el de las hembras. El choque térmico fue menos efectivo con solo el 34% de organismos que desovaron y el número de hembras fue superior al de los machos. El tiempo óptimo para realizar el desove fue entre 11 y 15 min de exposición al choque de salinidad, mientras que para el choque térmico fue entre 16 y 20 min

Morphogenetic components and accumulation in Mulato grass at different frequencies and intensities of grazing

En 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.Grasses 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 (2,769 kg dry matter at 14 d; 4,985 kg at 21 d; and 7,033 kg at 28 d). Under severe grazing in the first cycle, stem appearance rate was higher than under light grazing by 13 % in the northwinds season, by 8 % in the dry season and by 14 % in the rainy season. Leaf elongation was greatest at the 28 d frequency during the rainy season. Mulato grass exhibited the highest forage accumulation during the rainy season when harvested at a 28 d frequency under light grazing. Leaf elongation rate and leaf senescence exhibited the highest values when grazed lightly every 28 d at a low stem density