Zootecnia Tropical

Strategic use of sugar cane (Saccharum officinarum) in dual purpose pregnant heifers

Se llevó a cabo un experimento en la unidad experimental de bovinos del Centro Nacional de Investigaciones Agropecuarias, con la finalidad de evaluar el efecto del complementación con caña de azúcar durante el último tercio de la gestación en novillas mestizas Holstein sobre el peso pre y post parto, intervalo entre parto (IPP), peso al nacer y producción de leche. Se establecieron dos tratamientos: T1: pastoreo más alimento concentrado a razón de 1,5 kg/animal/día y T2: pastoreo más alimento concentrado más suministro de caña de azúcar enriquecida con úrea a razón de 4 kg/animal/día. Se utilizaron 14 novillas con un peso inicial de 495 kg, las cuales se distribuyeron en forma aleatorizada a los tratamientos en la medida que llegaban al séptimo mes de preñez, pastoreando en forma conjunta en potreros de pasto bermuda (Cynodon dactylon) con una carga animal de 2 UA/ha/año. Se utilizó un diseño completamente aleatorizado donde cada animal representó una réplica (siete/tratamiento). Los resultados no mostraron diferencias en el peso al nacer de los becerros y en el peso pre y postparto (P>0,05), pero sí en la ganancia diaria de peso de las novillas (P<0,01). El IPP fue menor en T2 (P<0,05), así como se obtuvo una mayor producción de leche en este último tratamiento (1269 vs. 1634 L/animal/lactancia). El costo de la leche fue mayor para T2, pero el ingreso neto en T1 fue menor (US $ 516 vs. 619). Se concluye que el uso estratégico de la caña de azúcar como recurso energético en novillas previo al parto incide en una mayor producción de leche por lactancia (1.269 vs. 1.634 kg/lactancia), disminuye el IPP (454 vs. 347 días) y mejora la ganancia de peso (669 vs. 956 g/animal/día).

It was carried out a trial in the experimental unit of the National Center of Agricultural Research to evaluate the effects of sugar cane supplementation in the last third period of gestation of dual purpose crossbred heifers on live weight of before and after parturition, calving interval, calving weight, and milk production. Animals (14), with a mean initial body weight of 495 kg, were randomly placed in two treatments: T1: grazing + 1.5 kg of concentrated feed/head/day and T2: grazing + 1.5 kg of concentrated feed/head/day + 4 kg of sugar cane with urea/head/day, as the animals approached to the seventh month of pregnancy. Grazing was on bermuda grass (Cynodon dactylon) with a carrying capacity of 2 animal units/ha/year. A complete randomly design was used, where each animal represented an experimental unit (seven per treatment), with a mean comparison through Tukey test. The results did not show significant differences (P>0.05) on calving weight and heifer live weights, before and after parturition. However, there was a significant difference (P<0.01) on heifer average daily gain. Calving interval was lower in T2 (P<0.05), but a higher milk production, with a mean of 1269 L/head/lactation, when it was compared to treatment T2 with a mean of 1634 L/head/lactation. Milk cost was higher for T2, but net income in T1 was lower with a mean of 516 and 619 US$, for T1 and T2, respectively. It can be concluded that sugar cane as energetic source in dual purpose crossbred heifers previous to parturition significantly affected animal response, such as higher milk production/lactation, lower calving interval, and improved body weight gain.

Productive and reproductive performance of three cattle genotypes in the Soconusco region, Chiapas, Mexico

Para evaluar el efecto del genotipo en el comportamiento productivo y reproductivo en condiciones del Soconusco, Chiapas, México, se utilizaron vacas de segundo parto Australian Friesian Sahiwal (AFS, n=10), Criollo Lechero Tropical (CLT, n=10) y Doble Propósito (DP, n=10) con sus crías. Las vacas pastorearon ad libitum una pradera establecida con pasto Estrella de Africa (Cynodon plechtostachyus) y en el corral recibieron 2 kg/animal de un concentrado comercial al momento de la ordeña. Las crías se alimentaron artificialmente con un substituto de leche. Las vacas se ordeñaron mecánicamente 2 veces por día sin el apoyo del becerro y cada 14 días se registraron el intervalo parto primer estro (IPPE), producción de leche (PL) y los cambios de peso corporal en vacas (CPCV) y becerros (CPCB). Se utilizo un diseño completamente al azar con 3 tratamientos (genotipos) y 10 repeticiones, considerando una vaca como la unidad experimental. El IPPE fue menor (P<0,01) en vacas AFS y CLT (37,2±7,4 y 55,1±20,3 d) que en vacas DP (93±1,8 d); la PL en vacas AFS (11,9±4,4 L/d) fue mayor (P<0,05) que en vacas DP y CLT (8,3±1,8 y 6,6±1,9 l/d, respectivamente). El CPCV fue similar (P>0,05) en vacas CLT, AFS y DP (1,0±12,8, -2±14,4 y -7,2±9,8 kg, respectivamente). Por otra parte, el CPCB fue similar (P>0,05) en becerros AFS (39,7±5,7 kg), CLT (33,5±13,3 kg) y DP (37,7±4,6 kg). Se concluye que las vacas Australian Friesian Sahiwal y Criollo Lechero Tropical mostraron el mejor comportamiento productivo y reproductivo que las Doble Propósito bajo las condiciones ambientales y de manejo del Soconusco, Chiapas, México.

To evaluate the effect of genotype on productive and reproductive performance under conditions of the Soconusco region, Chiapas, Mexico, Australian Friesian Sahiwal (AFS, n=10), Criollo Lechero Tropical (CLT, n=10), and Dual Purpose (DP, n=10) cows in their second parity with their calves were utilized. Cows grazed ad libitum a pasture established with African Star grass (Cynodon plechtostachyus), while in corral were given 2 kg/animal of a commercial concentrate during milking. Calves were artificially reared with a milk substitute. Cows were mechanically milked twice a day, without the presence of their calves, and the interval from calving to first estrus (ICFE), milk production per day (MP), and body weight changes in both cows (BWCO) and calves (BWCA) were registered every 14 days. It was utilized a completely randomized design with three treatments (genotypes) and 10 replications, taking a cow as the experimental unit. ICFE was shorter (P<0.01) in AFS and CLT cows (37.2±7.4 and 55.1±20.3 d, respectively), than in DP cows (93±1.8 d). MP in AFS cows (11.9±4.4 L/d) was higher (P<0.05) than in DP and CLT cows (8.3±1.8 and 6.6±1.9 l/d, respectively). BWCO was similar (P>0.05) in CLT, AFS, and DP cows (1±12.8, -2±14.4 and -7.4±9.8 kg, respectively). On the other hand, BWCA was similar (P>0.05) in AFS (39.7±5.7 kg), CLT (33.5±13.3), and DP (37.7±4.6 kg) calves. It is concluded that Australian Friesian Sahiwal and Criollo Lechero Tropical cows showed a better productive and reproductive performance than Dual Purpose cows under the environmental and management conditions of the Soconusco, Chiapas, Mexico.

Evaluation of the sustainability of two cattle models in the depressed saline plain of Tucumán, Argentina

Se evaluó la sostenibilidad de dos modelos físicos ganaderos de la llanura deprimida salina de Tucumán (área de probable expansión ganadera) en relación a indicadores ambientales, económicos y sociales. Se trabajó, durante 3 años, con dos modelos físicos pastoriles (Chloris gayana cv Finecut) de engorde de novillos con carga animal similar: T0 = pastoreo continuo (situación zonal preponderante) y T1 = pastoreo rotativo racional con suplementación estratégica. Dada la escala predial de la experiencia se seleccionaron prioritariamente indicadores ambientales. Se seleccionaron tres tipos de indicadores: 1) Ambientales: producción ganadera, cobertura de Chloris, malezas, mantillo, suelo desnudo, materia orgánica del suelo, estimación de CH4, riesgo de utilización de energía fósil; 2) Económicos: margen bruto de la actividad y 3) Social: responsabilidad técnica. Se utilizó una metodología que se basa en la determinación del Índice de Sostenibilidad (IS). Se tomaron como valores umbrales locales aquellos con un 20% superior a la exigencia de mejora o información bibliográfica. Los IS se calcularon como la relación entre el valor del indicador y el valor del umbral. El sistema será sostenible si el promedio de los índices de los indicadores es igual o mayor que uno, siendo uno el límite de sostenibilidad. En T0 con un IS de 0,58, ocho de los indicadores seleccionados no alcanzaron el límite, siendo particularmente inferiores la emisión de metano y la cobertura de Chloris. En T1, con aplicación de tecnología de insumos y de proceso, todos los indicadores superaron el límite de sostenibilidad, siendo el IS = 1,48. Este modelo sería una alternativa viable para el desarrollo ganadero sostenible de la llanura deprimida salina de Tucumán, logrando acondicionar novillos desde el desmadre hasta faena en 10 a 12 meses.

The sustainability of two physical cattle models of the depressed plain saline of Tucumán (area of probable cattle expansion) was evaluated in relation to environmental, economic, and social indicators. Work was done, during 3 years, with two physical models based in pasture (Chloris gayana cv Finecut) of young fattening steers with similar stocking rate: T0 = traditional continuous-grazing (preponderant zonal situation), and T1 = controlled grazing system with strategic supplementation. Given the farm scale of the experience, priority environmental indicators were selected: 1) Environmental: cattle production, Chloris cover, weeds, litter, bare ground, soil organic matter, CH4 estimate, risk of use of fossil energy; 2) Economic: gross margin of the activity, and 3) Social: technical responsibility. The methodology was based on the determination of the sustainability index (SI). Local values were taken as thresholds, plus a 20% as demand of improvement or bibliographical information. The SI were calculated as the relation between the indicator value and the threshold value. The system will be sustainable if the average of the SI is equal or greater than one, being one the limit of sustainability. In T0 with a SI of 0.58, seven of the selected indicators did not reach the limit, being methane estimation and Chloris cover particularly lower. In T1, with application of input technology and process, all the indicators surpassed the sustainability limit, being SI of 1.55. This model would be a feasible alternative for a sustainable cattle development of the depressed plain saline of Tucumán, obtaining young steers from weaning to task in 10 to 12 months.

**Efeito de soluções nutritivas na produção e qualidade nutricional da forragem hidropônica de trigo (Triticum aestivum L.)**

Com o objetivo de avaliar a produção e a qualidade nutricional da forragem hidropônica de trigo (Triticum aestivum L.) cultivado em ambiente protegido com soluções nutritivas inorgânicas e orgânicas parcialmente corrigidas, identificando a idade ideal de colheita, realizou-se um estudo no Departamento de Fitotecnia da Universidade Federal de Santa Maria. Adotou-se o delineamento experimental em blocos ao acaso, distribuídos em esquema fatorial 2x4 com duas soluções nutritivas: SIN: solução inorgânica segundo recomendação de Neves (2001) e SONC: solução orgânica parcialmente corrigida atendendo recomendação de Neves (2001) e quatro idades de colheita (4, 8, 12 e 16 dias). Foi observada significância (P<0,05) à interação soluções nutritivas x idades de colheita para as variáveis: estatura, fitomassa seca (FS), proteína bruta (PB), proteína solúvel (OS) e fibra em detergente neutro (FDN). Verificou-se para a SIN e SONC diminuição da FS, com o avanço da idade de colheita. A solução SONC proporcionou valores ligeiramente maiores de FS, PB e PS e menores de FDN em relação à SIN, em todas as idades de colheita. Não houve diferença significativa entre as soluções (P>0,05) para os teores de fibra em detergente ácido, lignina, celulose e digestibilidade in vitro da fitomassa seca. O aumento da idade de colheita promoveu maiores teores de FDA, lignina e celulose e menor digestibilidade in vitro da fitomassa seca (DIVFS). A idade de colheita ideal situa-se entre os 8-12 dias, pois neste período têm-se valores intermediários favorecendo o teor protéico sem comprometer a redução de FS e DIVFS devido ao maior teor fibras.

The objective of this study was to evaluate the effect of different nutrient solutions and harvest date on production and nutritive quality of hydroponic forage wheat (Triticum aestivum L.). The experiment was conducted inside a protected environment at Fitotecnia Department of the Universidade Federal at Santa Maria, Brazil. The experimental design was a randomized complete block. Treatments consisted of two nutrient solutions (SIN: inorganic solution by Neves (2001), and SONC: organic solution of the vermicompost) and four harvesting dates (4, 8, 12, and 16 days after emergence), distributed in a 2x4 factorial scheme. It was observed interaction (P<0.05) between nutrient solution and harvest date for the variables plant height, dry weight (DW), crude protein (CP), soluble protein (SP), and neutral detergent fiber (NDF). SONC and SIN showed a decrease in DW values when delayed harvest dates. SONC presented an increase in the values of DW, CP, and SP, but a decrease in NDF in comparison with SIN in all harvest dates. It was observed an increase in acid detergent fiber (ADF), lignin (LIG), and cellulose (CEL) and a decrease in digestibility in vitro when delaying the harvesting dates. It was not observed statistical difference (P>0.05) in ADF, LIG, CEL, and digestibility in vitro among the solutions. The best quality characteristics (CP and digestibility in vitro) of hydroponic forage wheat were obtained when harvest was 8 to 12 days after sowing.

Níveis de energia digestível na dieta de piauçu (Leporinus macrocephalus) no desenvolvimento testicular em estágio pós-larval

Objetivando-se determinar o efeito do nível de energia digestível da dieta no desenvolvimento testicular de piauçu (Leporinus macrocephalus) foram utilizados 600 peixes com peso e comprimento médio inicial de 0,33 ± 0,11 g e 2,94 ± 0,39 cm, respectivamente. Foram realizados quatro tratamentos (2.600, 2.700, 2.800 e 2.900 kcal de ED/kg de ração). Verificou-se que o nível de energia não influenciou o peso corporal médio final e comprimento total. Foi verificado efeito quadrático (P<0,02) no peso da gônada aos 60 dias. Foi verificado efeito quadrático (P<0,02) no índice gonadossomático aos 60 dias. Os peixes do tratamentos com 2.800 e 2.900 kcal de ED/kg apresentaram nítida formação de cistos de espermatogônias primárias e secundárias. Os animais dos grupos com 2.600 e 2.700 kcal de ED/kg apresentaram formação de cistos de espermatogônias primária, apenas.

The objective of this study was to evaluate the effect of energy levels on testicular development of the piauçu (Leporinus macrocephalus). Six hundred fishes, averaging initial weight and length of 0.33 ± 0.11 g and 2.94 ± 0.39, respectively, were utilized. The experiment was carried out according to a completely randomized design, with 4 treatments (2600, 2700, 2800, and 2900 kcal DE/kg). Energy level did not significantly affect average final body weight and total length. Quadratic effect on gonads weight (P<0.02) at 60 days was verified. Quadratic effect on the gonad-somatic index (P<0.02) at 60 days was verified. The treatments with 2800 and 2900 kcal DE/kg showed the primary and secondary spermatogonia rounded by Sertoli cells in a typical cyst formation. The treatments with 2600 and 2700 kcal DE/kg showed development of primary spermatogonia cyst only.

Comparação morfometrica e índices somáticos de machos e fêmeas do lambari prata (Astayanax scabripinnis Jerenyns, 1842) em diferente sistema de cultivo

Objetivou-se comparar a influência do sexo na morfometria e nos índices somáticos de lambari em condições de cultivo. Utilizou-se 270 alevinos de Lambari prata, com peso médio inicial 5,07 ± 0,14 g para machos, e as fêmeas com peso médio inicial de 6,67 ± 0,07 g, com 3 tratamentos: T1-machos na ausência de fêmea e T2-fêmeas na ausência de machos e T3-machos e fêmeas juntos. Para o comprimento total e padrão foi observado diferença significativa para fêmeas cultivadas na presença e ausência do macho em relação as machos cultivados na presença e ausência das fêmeas. Já comprimento do tronco, comprimento da cabeça e distância pré-anal não foi encontrada diferença significativa entre as fêmeas. Já as fêmeas na ausência de machos apresentaram diferenças significativas em relação aos machos cultivados na ausência e na presença das fêmeas. Para altura do corpo não foi encontrada diferença estatisticamente significativa entre os tratamentos. O índice gonadossomático foi estatisticamente diferente para fêmeas cultivadas na ausência do macho em relação aos machos cultivados na ausência e na presença das fêmeas, ao contrário do observado para índice hepatossomático que não houve diferença significativa entre os tratamentos.

This study was carried out to compare the influence of sex on Astyanax scabripinnis morfometric and reproductive indexes. Three fingerlings (live weight 5.07 ± 0.14) were assigned to three treatment groups: T1 male only; T2 female only, and T3 both sex. Female parameters measured were trunk length, head length, pre-anal distance, and body height. Significant differences for total and body length for cultivated females was observed in presence and absence of the male in relation to the cultivated males in presence and absence of the females. Length of the trunk, length of the head, and pre-anal were not significantly different between the females. Females in the absence of males had significant differences in relation to the males cultivated in absence and presence of the females. For height of the body, significant differences among treatments were not found. The results also revealed significant changes on the gonadossomatic index of T2 females in comparison to males from T1 and T3 groups. In the other hand, the hepatossomatic index did not show any significant change amongst groups.

Condition index of the mussels Perna perna and Perna viridis (Bivalvia:Mytilidae) under a suspended cultivation system in the Turpialito Bay, Cariaco Gulf, Venezuela

Con la finalidad de conocer la talla mínima de comercialización en fresco, se comparó el índice de condición de los mejillones Perna perna y Perna viridis colocados bajo sistema de cultivo suspendido en la Ensenada de Turpialito, Golfo de Cariaco (Julio 2002 a 2003). Mensualmente, se determinó la dimensión de la concha en función de la longitud máxima de su eje dorso-ventral, las masas secas del músculo, gónadas y el índice de condición en ambas especies. Al final del estudio, Perna perna presentó el mayor promedio de talla (95,92 mm) con respecto a P. viridis (73,61 mm). La variación en peso de los diferentes tejidos secos se relacionó con el índice de condición de ambas especies. P perna alcanzó su más alto índice (39,89%) en diciembre, mientras que P. viridis lo presentó en enero (20,62%), coincidiendo en ambos con el incremento de los tejidos reproductivos y el aumento de la clorofila a durante el período de surgencia. Sin embargo, la mayor variación del índice de condición fue observada en P. viridis, debido posiblemente a una mayor intensidad de los procesos de maduración y desove, lo cual se evidenció con el mas alto coeficiente de variación (0,19), indicando que la fluctuación anual en el proceso reproductivo es más acentuado, comportamiento típico de las especies tropicales, a pesar de generar menor tejido reproductivo por unidad de tiempo que P. perna en los períodos de desove.

With the purpose of knowing the minimum size of commercialization in fresh, it was compared the condition index of the mussels Perna perna and Perna viridis placed under a suspended cultivation system in Turpialito Bay, Gulf of Cariaco (July 2002 to 2003). Monthly, the dimension of the shell was determined as a function of the maximum ventral axis length, dry mass of the muscle, gonads, rest of soma, and the index of condition in both species. At the end of the study, P. perna presented the highest size growth (95.92 mm) compared to P. viridis (73.61 mm). The variation in weight of the dry mass was related to the condition index of both species. Perna perna showed the highest value (39.9%) in December, while P. viridis presented it in January (20.6%), coinciding in both species with an increment of the reproductive tissue and the increase of the chlorophyll a during the period of upwelling. However, the highest variability in the condition index was observed in P. viridis due to the higher intensity in the maturation processes and spawning, which was evidenced by the largest coefficient of variation (0.19). This indicates that the annual fluctuation in the reproductive process is more accentuated a typical behavior of tropical species, in spite of generating smaller reproductive tissues per unit of time than P. perna in the spawning periods.

Effect of microalgae size on the ingestion rate on larvae of Artemia franciscana (Kellog, 1906)

Se valoró el efecto que representa el tamaño de las microalgas Chaetoceros muelleri y Tetraselmis suecica sobre la tasa de ingestión de larvas de Artemia franciscana. Desde el inicio del ensayo se observaron diferencias significativas (P<0,05) en todos los estadios de desarrollo y los tratamientos evaluados. En todos los estadios larvales se presentó un incremento de la tasa de ingestión en relación la concentración de Chaetoceros muelleri. En la etapa de transición de metanauplio IV a postmetanauplio II, Artemia franciscana alcanzó a ingerir 3,5 veces más la diatomea que la microalga fitoflagelada. Este comportamiento desapareció hacia el final de la etapa de postmetanauplio IV, cuando fue similar la tasa de ingestión de ambas especies de microalgas.

The effect of the size of the microalgae Chaetoceros muelleri and Tetraselmis suecica on the ingestion rate of larvae of Artemia franciscana was evaluated. From the beginning of the experiment significant differences were observed (P<0.05) at all stages of development among the treatments. In all stages of the larvae there was observed an increase in the rate of ingestion relative to the concentration of C. muelleri. In the transition stage from metanauplii IV to postmetanauplii II, A. franciscana managed to ingest 3.5 times more diatom than the phytoflagelate algae; behavior that disappeared at the end of the postmetanauplii IV stage when they have in a equal relationship of 1 to 1.