Américo Fróes Garcez Neto

Respostas morfogênicas e estruturais de Panicum maximum cv. Mombaça sob diferentes níveis de adubação nitrogenada e alturas de corte

The morphogenetic and structural characteristics of Panicum maximum cv. Mombaca were evaluated in response to different levels of nitrogen supply and cutting regimes. The study was conducted in a glasshouse with natural conditions of light and temperature. Treatments corresponded to four levels of nitrogen supply (0, 50, 100 and 200 mg/dm3) and three cutting heights (5, 10 and 20 cm). The morphogenetic evaluations included leaf appearance and elongation rate, phyllochron and leaf lifespan. The structural measurements were: number of leaves, number of tillers and leaf lamina length of fully expanded leaves. The morphogenetic responses were affected by nitrogen supply during regrowth, highlighting the importance of that nutrient for manipulating sward structure. All variables responded positively to nitrogen supply, except phyllochron. Cutting height had a significant effect on leaf lifespan, leaf lamina length of fully expanded leaves and number of green leaves per tiller. Leaf appearance and elongation rate per tiller were increased in 133 and 104%, respectively, by nitrogen supply. The relationship between both group of variables was determinant for the characterization of the main vegetative changes on plants. The responses observed on morphogenetic characteristics comprise an efficient attribute to manipulate canopy structure, allowing improved allocation of productive resources to growth and developmental processes.

Morphological and structural characteristics and productivity of Brachiaria grass and forage peanut submitted to shading

The morphological and structural characteristics and dry matter production of signalgrass (Brachiaria decumbens, cv. Basilisk) and forage peanut (Arachis pintoi, cv. Amarillo) were evaluated in response to different shading levels (0, 50 and 70%). A randomized complete block design was used with four replications. Three and two harvests for signalgrass and forage peanut were made, respectively. Forage peanut showed significant reduction in dry matter production with shading, only in the second harvest. Dry matter production of signalgrass decreased linearly in the first and second harvest. In all the harvests evaluated, average sward height, petiole length, and stem and leaf blade length increased significantly with shading. Increasing shade levels promoted linear reduction in the tiller population density of signalgrass, in the three harvests evaluated. On the other hand, mean tiller weight was only affected in the third harvest, showing a linear increment with increasing shade levels. The leaf:stem ratio of signalgrass and forage peanut was not significantly altered by shade. Specific leaf area, leaf area per leaflet and leaf area per tiller increased with shading. Leaf area index (LAI) showed linear reduction with shading in the second harvest of forage peanut and signalgrass. Signalgrass and forage peanut have great potential for evaluation and use in silvopastoral systems where the light transmission level is around 50% of photosynthetically active radiation.The morphological and structural characteristics and dry matter production of signalgrass (Brachiaria decumbens, cv. Basilisk) and forage peanut (Arachis pintoi, cv. Amarillo) were evaluated in response to different shading levels (0, 50 and 70%). A randomized complete block design was used with four replications. Three and two harvests for signalgrass and forage peanut were made, respectively. Forage peanut showed significant reduction in dry matter production with shading, only in the second harvest. Dry matter production of signalgrass decreased linearly in the first and second harvest. In all the harvests evaluated, average sward height, petiole length, and stem and leaf blade length increased significantly with shading. Increasing shade levels promoted linear reduction in the tiller population density of signalgrass, in the three harvests evaluated. On the other hand, mean tiller weight was only affected in the third harvest, showing a linear increment with increasing shade levels. The leaf:stem ratio of signalgrass and forage peanut was not significantly altered by shade. Specific leaf area, leaf area per leaflet and leaf area per tiller increased with shading. Leaf area index (LAI) showed linear reduction with shading in the second harvest of forage peanut and signalgrass. Signalgrass and forage peanut have great potential for evaluation and use in silvopastoral systems where the light transmission level is around 50% of photosynthetically active radiation.

Licuri oil supplements for lactating cows on pasture

Lima, L. S., Oliveira, R. L., Garcez Neto, A. F., Bagaldo, A. R., Abreu, C. L., Silva, T. M., Carvalho, S. T. and Bezerra, L. R. 2015. Licuri oil supplements for lactating cows on pasture. Can. J. Anim. Sci. 95: 617-624. As licuri [Syagrus coronata (Martius) Beccari] oil can be a beneficial energy source in the diet of lactating cows managed on pasture, this study aimed to determine the most effective level of licuri oil in feed supplements. Sixteen Holstein×Zebu crossbreed lactating cows grazing on Tanzania (Panicum maximum) pasture grass were grouped into two 4×4 simultaneous Latin squares; there were four experimental periods of 21 d each, with 17 adaptation days and 4 d of data collection. The treatments were diets containing 0.0, 15.0, 30.0 or 45.0 g kg-1 of licuri oil in concentrated dry matter. The intakes of dry matter, crude protein and non-fiber carbohydrate levels were not affected by the addition of licuri oil; however, the intake of neutral detergent fiber and total digestible nutrients decreased linearly. Neutral detergent fiber digestibility was reduced linearly with increasing levels of licuri oil in the concentrate. There were no changes in blood glucose levels, but blood urea nitrogen levels varied according to the time of the day when the blood was collected. Inclusion of licuri oil at 45.0 g kg-1 in feed concentrates results in improved dry matter and ether extract digestibility.

Condição corporal e desempenho produtivo de cabras Alpinas no início de lactação

The objective of this study was to evaluate the influence of body condition at birth on Alpine goat productive parameters in early lactation. Sixty-eight females were assigned to three groups according to the body condition score (BCS) - low (1.00 - 2.75); intermediate (2.75 - 3.50) and high (3.50 - 5.00) and evaluated from kidding to the eighth week of lactation. The feed intake and milk production were recorded on a daily basis and the body weight, body condition score and milk composition at weekly intervals. Animals with a high body condition score presented lower dry matter intake, neutral detergent fiber and crude protein compared to those with low and intermediate body condition scores. The average time for dry matter intake recovery of the animals with the three body condition scores was 16 days (2.3 weeks) postpartum, and stabilization by the end of the experiment. In the sixth week of lactation, animals with low body condition score had the same body weight of animals with intermediate body condition score. There was no effect of the body condition at birth on the body condition score changes and milk production during the experiment. The milk fat content of animals with high body condition score was lower in the first two weeks postpartum compared to animals with low and intermediate body condition score. The high body condition at birth influences negatively the ad libtum intake of dairy goats in the early lactation, but when it is used feed of high quality with high energy levels, the influence of the body condition at birth is nil to variations in weight, BCS and milk production.

Body condition and metabolic profile of Alpine goats at the onset of lactation

Objetivou-se avaliar a influencia da condicao corporal ao parto sobre alguns metabolitos sanguineos em cabras no inicio da lactacao. As cabras (68 no total) foram distribuidas em tres grupos de acordo com o escore da condicao corporal (ECC) ao parto: entre 1,00 e 2,75 (animais magros); entre 2,75 e 3,50 (condicao corporal intermediaria); e entre 3,50 e 5,00 (animais gordos). O experimento foi realizado nos primeiros 60 dias de lactacao e as coletas de sangue, apos o parto e semanalmente ate a oitava semana de lactacao. Foram feitas analises para determinacao das concentracoes de acidos graxos nao-esterificados (AGNE), beta-hidroxibutirato (BHBA), glicose, colesterol total e lipoproteina de alta densidade (HDL). As concentracoes plasmaticas dos metabolitos nao diferiram entre os grupos. As concentracoes de AGNE, nos animais dos tres grupos, ao parto e nas oito primeiras semanas de lactacao, foram de 658,46 e 232,90 mg/dL, respectivamente, e os valores de BHBA ao parto, de 10,31 ± 3,0 mg/dL para os animais magros; 6,88 ± 0,9 mg/dL para os intermediarios; e 4,21 ± 0,8 mg/dL para os animais gordos. Os valores de glicose ao parto foram de 112,54 ± 15,4 mg/dL para os animais magros; 90,93 ± 13,5 mg/dL para os animais intermediarios; e 132,47 ± 26,7 mg/dL para os animais gordos. Os valores medios de colesterol total e de HDL nas oito primeiras semanas pos-parto foram de 109,01 ± 2,5 e 54,9 ± 1,39 mg/dL para os animais magros; 83,0 ± 21,7 e 56,0 ± 1,30 mg/dL para os intermediarios; e 84,3 23,9 e 54,5 ± 1,93 mg/dL para os gordos. As alteracoes no metabolismo energetico de cabras leiteiras de media producao diminuem, independentemente da condicao corporal ao parto, quando fornecida dieta de alta qualidade e com altos niveis de energia.

Níveis de farelo de melancia forrageira em dietas para ovinos

In order to study the inclusion of forage watermelon (Citrullus lanatus var. Citroides) meal (FWM) in pigeon pea hay based diets (Cajanus cajan) (PPH), a digestibility trial in sheep was carried out for testing five levels of FWM (20, 35, 50, 65 and 80%). Twenty lambs with an average age of six months and live weight of 11.2 kg (± 1.2) were used. The experimental period was twenty days for adaptation and five days for total refuses and feces collection. The chemical composition of diet ingredients was determined, being the levels of dry matter (DM) 95.3 and 95.75%, crude protein (CP) 18.7 and 16.8%, neutral detergent fiber (NDF) 38.8 and 64.3% for WFM and PPH, respectively. The water, DM, organic matter (OM), CP, ether extract (EE), NDF, acid detergent fiber (ADF), hemicellulosis (HCEL), non-fibrous carbohydrates (NFC), total carbohydrates (TCOH) intakes, as well as the DM, MO, CP, EE, NDF, ADF, HCEL and TCOH digestibilities were accurately measured. The DM, OM, CP, NDF, ADF, HCEL and TCOH intakes showed a quadratic behavior according to the FMF levels. The ether extract intake remained unchanged, while the NFC intake was linearly positive. The DM (58%), MO (69%), NDF (41%) and EE (85%) digestibility coefficients were not significantly influenced by the forage watermelon meal levels. The OM (54 to 62%), ADF (36 to 49%) and TCOH (47 to 58%) digestibility ranged linear and positively, while the HCEL digestibility showed the opposite behavior. The experimental diets provided dry matter intake enough to meet the animal requirements. The digestibility coefficients observed were satisfactory. The forage watermelon meal can be used in the guandu hay based diets in the levels from 35 to 66% of dry matter.

Composition and fatty acid profile of milk from cows on pasture subjected to licuri oil supplement

The objective of this study was to determine the best level of oil licuri concentrate on dairy cows. The best level was determined through an analysis of the milks chemical composition and fatty acid profile. Sixteen lactating cows from the Holstein × Zebu cross breed kept on Tanzania grass pastures were divided into four 4 × 4 Latin squares, which were formed by four experimental periods of 21 days. The 21-day experimental periods were divided into 17 days for adaptation and four days for collection. Cows received three kg of concentrate per day, at the time of milking. Treatments consisted of four types of feed containing the following levels: 0, 1.5, 3.0, and 4.5% inclusion of dry matter (DM) licuri oil concentrate. The licuri oil levels changed the fatty acids profile with a linear increase in the short-chain fatty acid and medium and linearly reduced the concentration of LCFA. The highest level of licuri oil was 4.5% of DM concentrate, which changed the composition of milk through an increase in the percentage of fat and total solids. This result is of prominent notice to the dairy industry.

Leaf tissues degradation of signalgrass hay pretreated with urea and submitted to in vitro digestion

An experiment using signalgrass hay treated with increasing urea levels (0, 20, 40, and 80 g/kg of dry matter), and submitted to in vitro digestion times (0, 6, 12, 24 or 72 hours) was conducted to evaluate the effects of ammoniation rates and digestion times on leaf blade tissue degradation. A completely randomized design with a 4 × 5 factorial treatment arrangement, with three replicates was used. Data were submitted to multivariate analysis. Urea-treated hay presented smaller proportion of remaining tissues measured in leaf blades cross-sections after in vitro digestion. Tissues more affected by urea treatment degradation were parenchyma bundle sheath and sclerenchyma. The hay treated with 80 g urea/kg DM and in vitro digested for 24 or 72 hours showed smallest proportion of tissues with thick and lignified cell walls such as parenchyma bundle sheath and sclerenchyma. The treatment with urea also reduced the time necessary to tissue degradation. The urea-treated hay in vitro digested for 12 hours, showed the same tissue proportion found in untreated hay submitted to 24 or 72 hours of in vitro digestion. The epidermis and lignified vascular tissue showed the smallest degradation following in vitro digestion. Results indicated that treatment of signalgrass hay with urea contributed to cell wall structure disruption, enhancement of tissues microbial degradation and reduction of the time necessary to digestion.

Disponibilidade, composição botânica e valor nutritivo da forragem de pastos consorciados, sob três taxas de lotação

The effect of three stocking rates on intake, botanical composition and the nutritive value of the forage from pastures of Brachiaria decumbens with Stylosanthes guianensis cv. Mineirao and B. brizantha cv. Marandu with S. guianensis cv. Mineirao was evaluated. The experimental design was a randomized complete block with treatments subdivided into plots with two replications. The design of the plots was a 2 x 3 factorial with 2 grasses (B. decumbens and B. brizantha cv. Marandu) in association with S. guianensis cv. Mineirao, three stocking rates (0.8, 1.2, and 1.6 AU/ha), and two sampling periods, corresponding to the dry season (July and October 1998); and to the rainy season (January and April 1999). Weaned Nellore steers with an average initial weight 138 kg were used. The DM availability in the mixed pastures with B. brizantha did not vary between sampling periods and had an average value of 3470 kg DM/ha. However, the pastures with B. decumbens the average for the rainy season (3485 kg DM/ha) was superior to that in the dry season (3056 kg DM/ha). The availability of the green fraction of the grasses was influenced negatively by the increase in stocking rate. During the rainy season, there was a higher proportion of grasses, for an estimated stocking rate of 1.17 AU/ha. B. decumbens pastures maintained a higher proportion of green forage and showed a higher nutritive value associated to a higher presence of legumes than in the B. brizantha pastures.

Production performance of lactating dairy cows at pasture fed concentrate supplemented with licuri oil

The objective of this study was to determine the optimal level of licuri oil to use in the concentrate of lactating dairy cows on pasture, through growth performance, feed conversion and cost of the supplementation. A total of 16 dairy cows, Holstein × Zebu crossbreed, were kept on Tanzania grass pasture. Cows were divided into four Latin squares, 4 × 4, formed by four experimental periods of 21 days, divided into 17 days for adaptation and four days for data collection. Cows received three kg of concentrate per day at the time of milking, and the treatments consisted of four diets containing licuri oil at levels of 0.0, 1.5, 3.0, and 4.5% of the concentrated dry matter. There was a linear increase in the daily milk yield, corrected to 3.5% fat, and an improvement in the feed conversion of the dry matter and neutral detergent fiber with the inclusion of the licuri oil. The optimal level of licuri oil was 1.5% of the concentrated DM for dairy cows on pasture, whose level has the best profit sale of milk, with positive results in the corrected daily milk production and conversion of the feed nutrients.