Genetic divergence among corn hybrids and combining ability for agronomic and bromatological traits of silage.

We assessed the impact of genetic divergence and the ability to combine corn hybrids used for the production of silage on the agronomic and bromatological traits of silage quality. We evaluated 18 corn hybrids used as genitors in a circulant diallel scheme in which each genitor hybrid participated in 9 hybrid combinations, and evaluated 100 treatments [18 genitor hybrids, 81 diallelic hybrids, and a commercial check hybrid (DKB330)] in a triple lattice 10 x 10 experimental design in two environments in Brazil. Genetic variability was adequate among the corn silage hybrids, and we can recommend the use of genitors 2B688 and P30B39 for the formation of a base population for intrapopulational breeding. The P30P34 hybrid is the best for intrapopulational breeding when aiming for silage with high protein content, low fiber content, and higher in vitro digestibility. Interpopulational breeding directed at improving silage digestibility can use a combination of genitors P30P34 and AS1572, but AS1572 and P30K64 are the most recommended. Hybrids 2B688, P30P34, and SG6015 are considered the most genetically distant of the others hybrids, and have desirable combining potential; therefore, they are important genitors for the formation of new segregated populations for improving corn silage.

Comportamento ingestivo e parâmetros sanguíneos em ovinos que receberam dietas contendo aditivos à base de extratos de própolis em pó / Ingestive behavior and blood profile in sheep fed with diets containing powdered propolis extract additives

Objetivou-se avaliar os efeitos do extrato de própolis (LLOSC2) sobre o comportamento ingestivo e os parâmetros sanguíneos em cordeiros alimentados com dieta concentrada. Foram utilizados quatro cordeiros machos, castrados, sem raça definida e com peso médio inicial de 32±1,92kg, mantidos em gaiolas metabólicas individuais durante todo o período experimental. O delineamento experimental foi em quadrado latino 4x4, com quatro animais, quatro dietas e quatro períodos experimentais. As dietas diferiram em relação à adição ou não de extratos de própolis à ração. As dietas testadas diferiam na adição de zero (controle), 1(88,16mg/g de flavonoides), duas (176,32mg/g de flavonoides) ou três (264,48mg/g de flavonoides) doses de aditivo à base de extrato de própolis LLOSC2. A dieta tinha relação volumoso:concentrado de 40:60 e foi formulada para ganhos de 250g. A ração concentrada era composta de milho e farelo de soja. O comportamento ingestivo dos animais foi observado por 24 horas, divididas em quatro períodos de seis horas. As coletas de sangue eram realizadas no último dia do período. Não houve efeito das doses LLOSC2 sobre o tempo despendido em alimentação, ruminação, ócio e ingestão de água. A duração do ciclo ruminativo foi maior nos animais que receberam duas doses de LLOSC2, e o número de movimentos mastigatórios também tendeu a aumentar no período que compreendia das 13 às 19h. Já a dieta contendo uma dose de LLOSC2 aumentou a duração da ruminação do bolo bem como o seu número total de mastigações no período de uma a sete horas. Houve uma diminuição nos níveis séricos de cortisol com a adição de três doses de LLOSC2. O hemograma, o leucograma, o perfil bioquímico e as imunoglobulinas não foram afetados pela inclusão das doses de LLSOC2. A administração de extrato de própolis LLOSC2 à dieta de ovinos não afetou seu comportamento ingestivo, os parâmetros hematológicos, bioquímicos e imunológicos estudados.(AU)

The objective of this study was to evaluate the effects of propolis extract (LLOS 2) on feeding behavior and blood parameters in lambs fed concentrate diet. Four male lambs were castrated, mongrel and average weight of 32±1.92kg, kept in individual metabolic cages throughout the trial period. The experimental design was a Latin square 4 x 4 with four animals, four treatments and four experimental periods. The diets differed according to addition or not of propolis extracts to feed. The experimental diets differed in addition to zero (control), 1 (88.16mg/g flavonoids) 2 (176.32mg/g flavonoids) or 3 (264.48mg/g flavonoids) Additive doses based on LLOSC2 propolis extract. The diet had a forage:concentrate ratio of 40:60 and was formulated to 250g gains. The concentrate ration was composed based on corn and soybean meal. The feeding behavior of the animals were observed for 24 hours, divided into four periods of 6 hours. Blood collections were made on the last day of the period. There was no effect of LLOSC2 doses on time spent eating, ruminating, leisure and water intake. The duration of the ruminative cycle was higher in animals that received two doses of LLOSC2 and the number of chewing movements also tended to increase in the period comprised from 13 to 19h. Since the diet containing a dose of LLOSC2, increased duration of rumination cake as well as its total number of chewing in the period of 1 to 7 hours. There was a decrease in serum cortisol with the addition of three doses of LLOSC2. The blood count, white blood cell count, biochemical profile and immunoglobulins were not affected by the inclusion of doses of LLSOC2. Administration of LLOSC2 propolis extract the sheep diet did not affect their feeding behavior, hematological, biochemical and immunological studies.(AU)

The effects of energy and protein supplementation strategy and frequency on the performance of beef cattle that grazed on Tanzania grass pastures during the rainy season.

The aim of the present study was to evaluate the different supplementation strategies for finishing Nellore beef cattle on pastures of Tanzania guinea grass (Panicum maximum Jacq. 'Tanzania'). The experiment was performed in a 12 ha area divided into 12 paddocks of 1 ha each. Forty-eight, 2-year-old, non-castrated Nellore cattle with an initial body weight (BW) of 384 kg (SEM = 21) were used in this study. The following supplementation strategies were evaluated: (1) mineral supplement supplied once per week (MS), (2) energy and protein supplement with intake regulator (2 g/kg BW) supplied once per week (EPS1), (3) energy and protein supplement (7 g/kg BW) supplied daily (EPS2), and (4) energy and protein supplement (7 g/kg BW) supplied three times per week (EPS3). The average daily gain (ADG) of animals receiving EPS3 was 0.177 kg/day higher than those receiving EPS1 (p < 0.01), 0.233 kg/day higher than the MS group, and not significantly different from EPS2. Animals in MS and EPS1 groups exhibited the lowest ADG. The ADG was not significantly different between EPS1 and EPS2 animals, but was 0.203 kg/day higher for EPS2 animals than for MS. Animals receiving only mineral supplementation spent more time grazing than the other supplementation groups tested (p < 0.01). We therefore conclude that Tanzania guinea grass is nutritionally limited and can be amended using supplements, thereby increasing animal performance. Animal performance was higher with increased protein and energy supplementation (7 g/kg BW), independent of the frequency with which supplements were administered.

Produção, quantidade e concentração de macronutrientes do material morto de capim-mombaça, fertilizado com fontes de fósforo / Production, amount and concentration of macronutrients of the death material in pasture of Mombaçagrass, fertilized with phosphorus sources

Avaliou-se o efeito da fonte de fósforo usado como fertilizante do capim-mombaça (Panicum maximum Jacq. cv. Mombaça) sob pastejo, sobre a produção de material morto, material senescente e liteira, e sobre a concentração e a quantidade de minerais (N, P, K, Ca e Mg) no material morto. No experimento, realizado no período de dezembro/2003 a abril/2004, utilizaram-se os tratamentos: testemunha (sem aplicação de fósforo), superfosfato simples+superfosfato triplo e Yoorin, os últimos usados como fonte de fósforo. O manejo do pasto foi realizado com novilhos em pastejo contínuo e cargas variáveis. Utilizou-se o delineamento em blocos completos ao acaso, com três repetições. A produção de material morto, senescente, liteira e a percentagem de material morto não foram diferentes segundo a fonte de fósforo. A produção de material morto variou de 4.521 a 5.097kg ha-1. A concentração e a quantidade de N, K, Ca e Mg no material morto foram semelhantes entre os tratamentos, a quantidade e a concentração de P foram diferentes segundo a fonte de fósforo, variando de 2,16 a 5,04kg ha-1 e 0,52 a 1,01gk g-1, respectivamente. O uso das fontes de fósforos não afetou a produção de massa seca de liteira, material senescente, material morto e a concentração e quantidade de minerais do material morto.

The effects of phosphorus sources (Yoorin, simple superphosphate (SS) + triple superphosphate (TS)) of fertilizers of Mombaçagrass (Panicum maximum Jacq. cv. Mombaça) pasture were evaluated on the death and senescent material, litter production, and concentration and amount of minerals (N, P, K, Ca, and Mg) in the pasture, under grazing. The experiment was carried out from December/2003 to April/2004. The grazing method was the continuous stocking and variable stocking rate, and the animals were crossbred. The design was a randomized complete block with three replications. The phosphorus source did not have significant effect on the death and senescent material and litter production, but the death material production ranged from 4,521 to 5,097kg ha-1. The phosphorus source did not have significant effect on the amount and concentration of N, K, Ca, and Mg. However, the phosphorus amount and concentration were different, influenced by the phosphorous source, ranging from 2,16 to 5,04kg ha-1 and 0,52 to 1,01gkg-1, respectively. The use of the phosphorus sources did not change the litter, senescent and death production, and the concentration and amount of minerals in the death material.