RESUMO -O estudo foi conduzido numa área de capim-Tanzânia (Panicum maximum), manejada em pastejo rotacionado para estimar o consumo de matéria seca de vacas em lactação. Os três tratamentos foram: vacas mestiças alimentadas com 3 kg de concentrado e vacas mestiças e Zebu (Gir) sem suplementação com concentrado. Observou-se uma quantidade de 7340,2 kg de matéria seca (MS) /ha de forragem disponível antes da ocupação e de 5.639,5 após o 3 o dia de ocupação. O consumo de MS de capim-Tanzânia foi 8,26 ± 5,66, 11,01 ± 5,37 e 9,55 ± 2,31 kg de MS/vaca/dia ou 2,15%, 2,37% e 2,34% do peso vivo, respectivamente para as vacas suplementadas, cruzadas não suplementadas e vacas Zebu . A média da produção de leite foi maior para o grupo suplementado (11,98 kg/vaca/dia). A produção de leite observada para as vacas não suplementadas foi similar. Produção de leite de 6,53 foi obtida pelas vacas cruzadas não suplementadas e 5,46 por vaca/dia foi produzida pelas vacas Zebu.Palavras-chave: consumo de matéria seca, gado Gir, pastagem tropical, vacas mestiças Estimation of Voluntary Intake of Tanzania Grass (Panicum maximum, Jacq. cv. Tanzânia) Rotationally Grazed by Lactating CowsABSTRACT -The trial was carried out in a Tanzania grass (Panicum maximum) pasture, rotationally grazed by lactating cows, to estimate the dry matter intake. Three treatments were tested: crossbred cows fed 3 kg per day of concentrate and crossbred and Zebu cows (Gyr) without concentrate supplementation. The forage availability was 7,340.2 kg of dry matter (DM) /ha before and 5,639.5 after the 3 rd grazing day. The Tanzania grass DM intake was 8.26 ± 5.66, 11.01 ± 5.37 and 9.55 ± 2.31 kg of DM/cow/day per day or 2.15, 2.37 and 2.34% of live weight, respectively, for the supplemented crossbred cows and non supplemented crossbred and Zebu cows. The average milk production was higher for the supplemented group (11.98 kg/cow/day). The milk production observed by the non supplemented cows was similar. Milk yield of 6.53 was obtained for non supplemented crossbred cows and 5.46 kg per cow/day was performed for the Zebu cows.

RESUMO -O presente trabalho foi conduzido com o objetivo de avaliar a degradabilidade ruminal da matéria seca (MS), fibra em detergente neutro (FDN) e amido, além de pH, amônia e ácidos graxos voláteis ruminais, em bovinos alimentados com silagens de milho (SMi), de raspa de mandioca com polpa cítrica (SRp), de casca de mandioca com polpa cítrica (SCc) e de cana-de-açúcar com polpa cítrica (SCn). Foram utilizados quatro novilhos, mestiços, castrados, canulados no rúmen e duodeno, em quatro períodos experimentais, com 11 dias de adaptação à dieta e oito dias de coleta. O delineamento experimental foi o quadrado latino 4x4. Foram adotados oito horários para a incubação das silagens: 3, 6, 12, 24, 48, 72, 96 Ruminal Fermentation and Degradability in Bovine Fed Diet with Cassava Residue and Sugar Cane Ensiled with Pelleted Citrus PulpABSTRACT -The objective of this work was to evaluate the dry matter (DM), neutral detergente fiber (NDF) and starch ruminal degradability besides pH, N-NH 3 and valatile fatty acids (VFA) in bovines fed diet with corn (CS), cassava meal (CMS), cassava hull (CHS), and sugar cane (SCS). The CMS, CHS and SCS were ensiled with citrus pulp (CPP). Four crossbred, castrated, rumen and duodenum cannulated steers were used in four experimental periods, with 11 days for diet adaptation and 8 days for sampling. The experimental design was 4x4 Latin Square. There were eight incubations times: 3, 6, 12, 24, 48, 72, 96 and 120 hours. The CMS showed higher DM, and NDF effective degradation (Kp 5%) (48.44 and 45.78%, respectively) than CS (45.50, 23.75%), CHS (43.87, 24.20%) and SCS (40.76, 25.78%). For all the treatments, the pH and the ruminal concentration of N-NH 3 were appropriate for the growth of the rumen microrganisms. The VFA values of the CS, CMS and CHS treatments were similar among themselves and higher than the SCS treatment.

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RESUMO -Este trabalho foi conduzido com o objetivo de avaliar a digestibilidade da energia e da fibra de dietas contendo uréia, amiréia ou farelo de algodão como fontes protéicas exclusivas e silagem de milho como volumoso. Utilizaram-se 24 borregos com 11 meses de idade e peso médio 31 kg e o método da coleta total de fezes. A ingestão de matéria seca foi de 64,1; 68,8 e 71,4 g/kg PV 0,75 /dia e as digestibilidades da energia da FDN e da FB foram 63,0; 67,7 e 64,4%, 39,6; 55,7 e 50,0%, 47,0; 49,3 e 53,4%, respectivamente, para dietas com uréia, amiréia e farelo de algodão. Os ganhos em peso foram 278,5; 348,0; e 293,7 g/anim.dia, na mesma ordem. O uso da amiréia poderá ser o mais adequado, em relação a uréia e farelo de algodão, em dietas para borregos contendo silagem de milho como volumoso.Palavras-chave: amiréia, digestibilidade aparente, energia, farelo de algodão, FDN, uréia Apparent Digestibility of Energy and Fiber of Sheep Diets Containing Urea, Starea or Cottonseed MealABSTRACT -This research was conducted to evaluate the energy and the fiber digestibility of diets containing urea, starea and cottonseed meal as nitrogen sources and corn silage as forage. Twenty-four lambs averaging 11 months old and initial 31 kg LW and total feces collection method were used. Dry matter intake was 64.1, 68.8 and 71.4 g /kg PV .75 /day and the energy, NDF and CF digestibilities were 63.0, 67.7 and 64.4%, 39.6, 55.7 and 50.0%, 47.0, 49.3 and 53.4%, for the diets with urea, starea and cottonseed meal, respectively. The average weights gain were 278.5, 348.0 and 293.7 g/anim./day, in the same above sequence. The use of starea would be more adequate in relation to urea and cottonseed meal in diets with corn silage as forage for lambs.Key Words: apparent digestibility, cottonseed meal, energy, NDF, starea, urea IntroduçãoA fonte protéica utilizada em uma dieta poderá proporcionar diferentes desempenhos aos animais, havendo, assim, o interesse em estudar fontes de proteína verdadeira e de nitrogênio não-protéico (NNP), como a uréia e a amiréia, esta resultante da extrusão da uréia com uma ou mais fontes de amido.Entre as fontes de NNP, a uréia é a mais comum e de custo mais acessível. Segundo CAMPLING et al. (1960) e RUSSELL et al. ( 1992, esta fonte é prontamente utilizada para a síntese de proteína microbiana no rúmen e atua no crescimento das bactérias digestoras de fibra. Um dos fatores que limita a utilização da uréia é a aceitação pelos animais e sua total solubilidade no ambiente ruminal, o que motivou STILES et al. (1970) e HELMER e BARTLEY (1971) a estudarem processos que minimizassem essas duas características. O excesso de nitrogênio amoniacal (N-NH 3 ) formado no rúmen poderá, além de acarretar toxicidade, constituir um desperdício energético, ao necessitar energia para eliminar o excesso no sangue. A redução da velocidade de hidrólise em aproximadamente 20%, por intermédio do processo de sua extrusão com o amido de milho, trigo ou mandioca ( EZEQUIEL et al., 2000;SILVA, 1999) ou pela adsorção com argilas como a...

Resumo -O objetivo deste trabalho foi avaliar os impactos ambientais do manejo agroecológico da caatinga, em unidades de produção familiar no Rio Grande do Norte, pelo método Ambitec de produção animaldimensão ambiental, desenvolvido pela Embrapa Meio Ambiente. Foram avaliadas sete unidades de produção familiar, em quatro projetos de assentamentos de reforma agrária do Município de Apodi, RN. Os dados para o levantamento foram obtidos por meio de questionários aplicados aos representantes das unidades produtivas familiares, que atribuíram, a cada variável estudada, um valor que representou a alteração proporcionada pela implementação da tecnologia. Após a inserção dos coeficientes de alteração de cada variável dos indicadores por unidade de produção, o coeficiente de impacto foi automaticamente calculado por meio da planilha Ambitec. O manejo agroecológico da caatinga resultou num impacto ambiental positivo, e suas maiores contribuições foram relacionadas aos efeitos positivos dos seguintes indicadores: capacidade produtiva do solo, uso de insumos materiais, qualidade do produto e diminuição da emissão de poluentes à atmosfera. Dois indicadores geraram efeitos negativos: o uso de energia e o uso de recursos naturais. Pela superioridade dos benefícios gerados, o manejo agroecológico da caatinga é uma inovação tecnológica geradora de impactos ambientais positivos.Termos para indexação: agricultura familiar, agroecologia, degradação ambiental, meio ambiente, sustentabilidade. Environmental impacts of caatinga agroecological handling in Rio Grande do Norte, BrazilAbstract -The objective of this work was to evaluate the environmental impacts of caatinga agroecological handling, in production unities of family farms, in Rio Grande do Norte, using the method Ambitec of animal production -environmental dimension, developed by Embrapa Meio Ambiente. Seven family farm production units were evaluated within four projects of agrarian reform in the county of Apodi, RN, Brazil. The data for surveying were obtained through applying queries to the responsibles for the production units, who attributed -to each studied variable -a value which represented the alteration resulted from the technology implementation. After insertion of the alteration coeficients of each indicator by production unit, the impact coeficients was automatically calculated using Ambitec sheet. The caatinga agroecological handling had a positive environmental impact, and its major contributions were related to the positive effects of the following indicators: soil production capacity, use of material input, product quality, and decrease of pollution emission to atmosphere. Two indicators had negative impact scores: energy use and use of natural resources. By the superiority of the benefits, caatinga agroecological handling is a technology innovation which generates positive environmental impacts.

To compare the integrated crop-livestock-forest (ICLF) and crop-livestock (ICL) systems in relation to thermal comfort and grazing behavior of Girolando heifers, a 2 × 2 crossover trial (two system and two periods) was carried out with eight ¾ Holstein × ¼ Gyr heifers in Xaraés–palisade grass pasture under intermittent stocking with 10 days of occupation period and 20 days of resting. In ICLF, crown cover of eucalyptus planted in rows was 65% at the beginning of the experiment. Animal behavior was assessed through bioacoustics by recording heifers’ sounds for 48 hours. Concomitantly, heifers’ internal temperature (IT,°C) was recorded every 10 min using data logger thermometers adapted to hormone-free intravaginal devices. Air temperature and humidity data were collected by thermohygrometers located in the center of ICLF and ICL for calculating Temperature–Humidity Index (THI). According to THI values, ICLF and ICL did not vary in terms of thermal comfort. However, THI indicated moderate stress (82.26±4.40) during day (06:00 to 17:59h) and mild stress (75.76±4.38) at night (18:00 to 05:59h) in both systems. During day, heifers from ICL had significantly (p < 0.05) higher IT (39.51±0.56oC) than those from ICLF (39.41±0.56oC); the former spent more time grazing and less time drinking water in ICLF (581.35±30.1 and 4.87±1.09 min, respectively) when compared with those from ICL (436.88±28.1 and 10.25±1.09 min, respectively). Therefore, although thermal comfort index did not vary between the systems, under moderate stress, crossbred heifers have lower internal temperatures, resulting in longer diurnal grazing and shorter water drinking time in Eucalyptus-shaded pastures.

Insulin growth factor I (IGF-I) and prolactin (PRL) are peptide hormones that exert complementary effects on reproductive traits by acting on folliculogenesis. In view of the lack of information about the IGF-I and PRL genes in Bos indicus, the objective of this study was to partially characterize the promoter regions of these genes and to screen animals of different ages at first pregnancy for the presence of polymorphisms in these regions. In addition, we determined whether polymorphisms influence the regulation of the two hormone genes, evaluating their association with sexual precocity. The animals were divided into three groups according to age at first pregnancy: 1) 100 heifers considered to be sexually precocious that became pregnant at 15-16 months of age, 2) 100 heifers that became pregnant during the normal breeding season at 24 months of age, and 3) 100 heifers that did not become pregnant until 24 months of age. For the IGF-I gene, PCR-RFLP-SnaBI analysis showed the presence of genotypes AB and BB at frequencies of 0.02 and 0.98, respectively. Sequencing of the IGF-I gene fragment revealed a single nitrogen base change from cytosine to thymine, corresponding to the restriction site of SnaBI. The polymorphisms identified in the 5’-flanking region of the IGF-I gene may serve as a basis for future studies of molecular markers in cattle. For the PRL gene, PCR-RFLP-HaeIII analysis showed the presence of only one migration pattern, a finding characterizing the region studied as monomorphic. The study of other regions in the IGF-I and PRL genes might provide molecular data that can be used in the future for the selection of sexually precocious animals

Little knowledge on initial behavior of native tree species in recovering landscapes in the Amazon is a current concern for expanding reforestation in the region. Thus, the aim of this study was to evaluate the establishment of native tree species that could be used for reforestation in area previously covered by a pasture of brachiaria grass (Brachiaria brizantha) destined for intensive cattle rasing in the State of Rondônia. For this, there were performed previous diagnostic of landscape changes and the election of tree species based on the ecological group information. Some of the critical macronutrients for plant growth were supplied in the holes to alleviate nutrient deficiencies. In addition, growth and survival parameters were taken to evaluate the initial behavior of species. Six native tree species planted with different combinations (10mx10m, 5mx5m and 3mx3m) had survival rate and growth (total height, girth stem and crown projection area) measured in different intervals: 6-month, 12-month and 24-month after planting. All the species presented survival rate over 90% at 24 months and comparable growth indices to other native species under similar situation and in the region. Overall, Schizolobium amazonicum (bandarra), the non-identified legume tree 1 (acácia grande) and Colubrina glandulosa (sóbrasil) averaged over 90% the highest girth stem growth all over the area. S. amazonicum and the non-identified legume tree 1 (acácia grande) presented the best results for height and canopy area growth parameters, respectively. The combination among native tree species from initial successional ecological groups and fertilizer was favorable to promote reforestation in the conditions of the study area in Rondônia.