Respirometry and Ruminant Nutrition

The gaseous exchange between an organism and the environment is measured by respirometry or indirect calorimetry. Once the oxygen consumption (O2) and the production of carbon dioxide (CO2) and methane (CH4) are known, the energy losses by gas and heat can be calculated. Energy metabolism and methane production have been studied in the Calorimetry and Metabolism Laboratory of the Federal University of Minas Gerais, located in Belo Horizonte, Minas Gerais, Brazil. Animals used are mainly Zebu cattle and their crossbreeds that represent most beef and dairy cattle breed grazed on tropical pastures. System calibration and routine work are addressed in this text. The results obtained on respirometric chambers are expressed in net energy (NE), which can be net energy for maintenance (NEm), lactation (NEL), weight gain (NEg), and pregnancy (NEp). NE is, in fact, what is used by the animal for maintenance and each productive function. The values of k (conversion efficiency of ME into NE) for maintenance (km), milk (kL), weight gain or growth (kg), and pregnancy (kp) are determined. Thanks to the peculiarity of the respirometric technique, the same animal can be evaluated several times, in different physiological states and planes of nutrition

Digestibilidade in vitro e in situ de três forrageiras tropicais colhidas manualmente e por vacas fistuladas no esôfago = In vitro and in situ digestibility of three tropical forages collected manually and by esophageal fistulated cows

Avaliou-se a digestibilidade in vitro (DIV) e in situ da matéria seca (MS) e “in situ” da proteína bruta (PB), fibra em detergente neutro (FDN) e fibra em detergente ácido (FDA), celulose e hemicelulose das gramíneas Colonião (Pannicum maximum) (COL), Brachiaria decumbens (BRACH) e Napier (Pennisetum purpureum) (NAP) de amostras colhidasmanualmente e por vacas portadoras de cânula no esôfago. A DIV-MS das gramíneas colhidas, manualmente, foi de 64% para NAP, 63% para BRACH e 55% para COL. A fração insolúvel potencialmente degradável (%) e a taxa de degradação (% h-1) das gramíneas NAP, BRACH e COL foram, respectivamente, de 62,8 e 6,4; 64,7 e 5,0 e 65,7 e 4,0 para a MS;62,0 e 4,2; 62,6 e 3,0 e 70,8 e 2,6 para a PB; 77,2 e 6,3; 75,5 e 4,9 e 70,1 e 3,7 para a FDN. Concluiu-se que a oferta de forragem estudada permitiu aos bovinos seleção dos alimentos de forma a se obter dietas com valores nutritivos superiores aos disponíveis nas pastagens e que para o sistema de pastejo contínuo com carga animal variável, a gramínea Napier mostrou-se mais digestível, seguida pela Braquiária e pelo Colonião que apresentou os menores parâmetros de degradação ruminal.<br><br>This study evaluated in vitro (IV) and in situ dry mater (DM) digestibility, as well as in situ crude protein (CP), neutral (NDF) and acid (ADF) detergent fiber, cellulose and hemicellulose degradability of Colonião (Pannicum maximum) (COL), Brachiaria decumbens (BRACH), and Napier (Pennisetum purpureum) (NAP) grasses. The grasses were collected manually and from esophagealfistulated cows. The IV-DM digestibility of the manually collected samples were 64% for NAP, 63% for BRACH and 55% for COL. The insoluble potentially degradable fraction (%) and the degradation rate (% h-1) of NAP, BRACH and COL grasses were 62.8 and 6.4,64.7 and 5.0, and 65.7 and 4.0 for DM; 62.0 and 4.2, 62.6 and 3.0, and 70.8 and 2.6 for CP; 77.2 and 6.3, 75.5 and 4.9, and 70.1 and 3.7 for NDF, respectively. It was concluded that forage availability was adequate and allowed forage selection by cattle, as the selected dietwas more nutritive than the manually collected grass. For pasture systems with variable animal weight per hectare, Napier grass had higher digestibility, followed by Brachiaria and Colonião, which showed the lowest degradation values

Digestibilidade in vitro e in situ de três forrageiras tropicais colhidas manualmente e por vacas fistuladas no esôfago - DOI: 10.4025/actascianimsci.v30i2.4701

This study evaluated in vitro (IV) and in situ dry mater (DM) digestibility, as well as in situ crude protein (CP), neutral (NDF) and acid (ADF) detergent fiber, cellulose and hemicellulose degradability of Colonião (Pannicum maximum) (COL), Brachiaria decumbens (BRACH), and Napier (Pennisetum purpureum) (NAP) grasses. The grasses were collected manually and from esophageal fistulated cows. The IV-DM digestibility of the manually collected samples were 64% for NAP, 63% for BRACH and 55% for COL. The insoluble potentially degradable fraction (%) and the degradation rate (% h-1) of NAP, BRACH and COL grasses were 62.8 and 6.4, 64.7 and 5.0, and 65.7 and 4.0 for DM; 62.0 and 4.2, 62.6 and 3.0, and 70.8 and 2.6 for CP; 77.2 and 6.3, 75.5 and 4.9, and 70.1 and 3.7 for NDF, respectively. It was concluded that forage availability was adequate and allowed forage selection by cattle, as the selected diet was more nutritive than the manually collected grass. For pasture systems with variable animal weight per hectare, Napier grass had higher digestibility, followed by Brachiaria and Colonião, which showed the lowest degradation values.Avaliou-se a digestibilidade in vitro (DIV) e in sit

CHEMICAL AND FERMENTATIVE CHARACTERISTICS OF ELEPHANT GRASS ENSILED WITH INCREAS-ING LEVELS OF DENIDRATED CASHEW FRUIT BY-PRODUCT CARACTERÍSTICAS QUÍMICAS E FERMENTATIVAS DO CAPIM-ELEFANTE ENSILADO COM NÍVEIS CRESCENTES DE SUBPRODUTO DA AGROINDÚSTRIA DO CAJU

&lt;p class="MsoNormal"&gt;&lt;span&gt;Nutritive value of silages of Elephant grass (Pen-nisetum&lt;span&gt;   &lt;/span&gt;purpureum, Schum.) mixed with 0; 3.5%; 7.0%; 10.5% and 14.0 %&lt;span&gt;  &lt;/span&gt;of dehydrated by product from juice industry of cashew fruit (Anacardium&lt;span&gt; &lt;/span&gt;occidentale, L) (DBC) was determined. A randomized design was used with four replicates. Silages were opened after 65 days and samples taken for analysis of dry matter (DM), crude protein (CP), neutral detergent fiber (NDF), acid detergent fiber (ADF), hemicellulose HCEL), cellulose (CEL), lig-nin (LIG), crude energy (CE), ash, neutral detergent inso-luble nitrogen (NDIN) and acid detergent insoluble nitro-gen (ADIN). &lt;/span&gt;Were also analyzed, pH, ammonia nitrogen and organic acids (lactic, acetic, butyric and propionic). Regarding fermentative parameters, there was an expected decrease in pH and the increasing levels of DBC did not affect the concentrations of N-NH3/NT and organic acids. It is concluded that dehydrated cashew by product can be ensiled along with Elephant grass without altering its fer-mentative characteristics. On the other side, the increased cell walls and ADIN contents of the silage may affect its nutritional value. &lt;/p&gt; Key-words: Cashew byproducts, nutritive value, tropical grass. &lt;p class="MsoNormal"&gt;O trabalho foi desenvolvido com o objetivo de se avaliar o valor nutritivo das silagens de capim-elefante (Pennisetum purpureum, Schum.) com adição de 0%; 3,5%; 7%; 10,% e 14% do subproduto do pseudofruto do caju (Anacardium occidentale, L.) desidratado (subproduto da agroindústria do suco de caju). Utilizou-se o delineamento inteiramente casualizado, com quatro repetições. Após 65 dias, os silos foram abertos e coletadas amostras para determinação dos teores de matéria seca (MS), proteína bruta (PB), fibra em detergente neutro (FDN), fibra em detergente ácido (FDA), hemicelulose (HCEL), celulose (CEL), lignina (LIG), energia bruta (EB), cinzas, nitrogênio insolúvel em detergente neutro (NIDN) e nitrogênio insolúvel em detergente ácido (NIDA). Para avaliar as características fermentativas das silagens, determinaram-se os valores de pH e os teores de nitrogênio amoniacal (% do nitrogênio total) e dos ácidos lático, acético, butírico e propiônico. A adição do subproduto do pseudofruto do caju desidratado (SPCD) acarretou o aumento dos teores de MS, PB, FDA, LIG, NIDN e NIDA. Para os parâmetros fermentativos, observou-se redução dos valores de pH, porém não se registrou influência dos níveis de adição do SPCD sobre os teores de N-NH3/NT e ácidos orgânicos. Conclui-se que o subproduto do pseudofruto do caju desidratado pode ser ensilado com o capim-elefante, sem comprometer as características fermentativas das silagens de capim-elefante. Porém, o aumento nos componentes da parede celular e do NIDA pode comprometer o valor nutri-cional do ensilado final. &lt;/p&gt; Palavras-chaves: Gramínea tropical, subprodutos do caju, valor nutritivo

Nutritional evaluation of elephant-grass silages with different levels of by-products from the cashew juice industry

ABSTRACT This study was conducted to evaluate the intake, apparent digestibility (AD), and degradability in situ of elephant grass (Pennisetum purpureum Schum) silages containing 0, 35.0, 70.0, 105.0, and 140.0 g kg-1 by-product from dried cashew apple (DCBP) (as fed basis). A completely randomized design with four replicates was adopted. For the study of degradability in situ, one adult male cattle was used in a completely randomized design with split plots. Intake and AD of dry matter (DM), crude protein (CP), neutral detergent fiber (NDF), acid detergent fiber (ADF), hemicellulose, and cellulose were evaluated, and the digestible energy (DE) and nitrogen balance (NB) of the silages were determined. The degradability in situ of DM, CP, and NDF was also determined. Addition of DCBP provided an increase in the intakes of DM, CP, NDF, and ADF. No effects of the levels of addition of DCBP were observed on the coefficients of AD of the silages. Regarding NB, positive values were only detected in the treatment with 105.0 g kg-1 DCBP. In the analysis of the degradability in situ, the incubation periods increased the rates of disappearance of DM, CP, and NDF. However, no effect of the levels of DCBP were observed on the effective degradability of DM. The by-product from dried cashew apple can be included at up to 140.0 g kg-1 in silages of elephant grass, but the high contents of acid detergent insoluble nitrogen may compromise the use and availability of nitrogen to the animals

Protein digestibility of ruminant feeds by the three-step procedure Digestibilidade da proteína de alimentos utilizados na alimentação de ruminantes pelo método das três etapas

The three-step procedure was used to evaluate ruminal degradable and undegradable protein of soybean meal (SM), sorghum grain (SG), cottonseed (CT), corn silage (CS) and tomato byproduct (TBP). Feeds were initially incubated in rumen of fistulated steers for 16 h. After that, 15mg of nitrogen were submitted to acid pepsin, for one hour, and alkaline pepsin for 24 h. The SM and CT showed 97 and 93% total protein digestibility, which is the major portion available in the rumen (94 and 92% respectively). The SG protein showed the lowest digestibility (73%) followed by TBP and CS that had 72 and 73% total protein digestibility. It was concluded that SM and CT showed high protein digestibility, however the most portion was degraded in the rumen and that besides the high lignin proportion, the TBP was the one which supplied more available intestinal protein.Avaliaram-se as proporções de proteína degradável e não-degradável no rúmen do farelo de soja (FS), sorgo grão (SG), caroço de algodão (CA), silagem de milho (SM) e do resíduo industrial de tomate (RIT) pelo método das três etapas. Os alimentos foram inicialmente incubados por 16h no rúmen de bovinos fistulados. Posteriormente, uma quantidade que continha 15mg de nitrogênio foi submetida à digestão em pepsina ácida por uma hora e em pancreatina alcalina por 24h. O FS e o CA apresentaram 97 e 93% de digestibilidade da PB, estando a maior parte desse nitrogênio disponível no rúmen (94 e 92% respectivamente). A proteína do SG apresentou o menor valor de digestibilidade (64%), sendo seguida pelo RIT e pela SM, que apresentaram 72 e 73% de proteína total digestível. Concluiuse que o FS e o CA apresentaram elevada digestibilidade da proteína, entretanto, a maior parte do desaparecimento ocorreu no rúmen. Apesar da elevada proporção de proteína indigestível, o RIT foi o alimento que mais disponibilizou proteína para ser digerida no intestino

Degradabilidade in situ do capim elefante ensilado com níveis crescentes de subproduto da agroindústria do abacaxi

The objective of this study was to evaluate the in situ degradability of dry matter (DM), crude protein (CP), neutral detergent fiber (NDF), acid detergent fiber (ADF), and hemicellulose of elephant grass (Pennisetumpurpureum, Schum.) with increasing levels (0; 35.0; 70.0, 105.0, and 140.0 g kg-1) of dried pineapple (Ananascomosus, L.) by-product (DPBP). The experimental silos consisted of plastic drums with 210 L capacity. After weighing and homogenizing the elephant grass with the DABP, the material was inserted in the silos (126 kg silage, at a density of 600 kg m-3) and compressed. After 45 days of ensilage, silos were opened and samples of the silages were collected for the trial. The study of degradability in situ was conducted using a rumen-fistulated male cattle. The animal was fed with corn silage supplemented with 1 kg concentrate daily. Five levels of addition of the by-product were tested, with three replicates and five times of incubation with an animal. The experimental design was completely randomized with split plots, in which the proportions of DPBP were the treatments (plots), the different silos were the replicates, and the incubation times were the subplots. The levels of inclusion of DPBP provided an increase (P < 0.05) in disappearance of DM and CP and in the effective degradability of DM, NDF, ADF, and hemicellulose. The dried pineapple by-product is a potential alternative to be used as additive in the ensilage of elephant grass, as it provides an increase in the rumen degradability parameters.Avaliaram-se a degradabilidadein situ da matéria seca (MS), proteína bruta (PB), fibra em detergente neutro (FDN), fibra em detergente ácido (FDA), e hemicelulose das silagens de capim elefante (Pennisetum purpureum, Schum.) com níveis (0; 35,0; 70,0; 105,0 e 140,0 g kg-1) crescentes do subproduto do abacaxi (Ananas comosus, L.) desidratado (SABD). Como silos experimentais foram utilizados tambores plásticos de 210 L de capacidade. Em cada silo foram colocados 126 kg de forragem, de forma que atingisse uma densidade de 600 kg m-3. Após a pesagem e homogeneização do capim elefante com o SABD, o material foi compactado no interior do silo, durante o carregamento. Após 45 dias de ensilagem, os silos foram abertos, e coletadas amostras das silagens para realização do ensaio de degradabilidade. O estudo de degradabilidade in situ foi conduzido utilizando um bovino adulto macho, fistulado no rúmen, alimentado com silagem de milho suplementada com concentrado 1 kg dia-1. Os cinco níveis de adição do subproduto foram testados com três repetições e cinco tempos de incubação, em delineamento inteiramente casualizado com parcelas subdivididas, sendo as proporções de SABD, os tratamentos (parcelas); os diferentes silos eram as repetições e os tempos de incubação eram as subparcelas. Os níveis de inclusão do SABD proporcionaram aumento (P < 0,05) no desaparecimento da MS, PB e nas degradabilidades efetivas da MS, FDN, FDA e hemicelulose. O subproduto do abacaxi desidratado constitui alternativa potencial para ser utilizado como aditivo na ensilagem do capim elefante, pois promove incremento nos parâmetros de degradabilidade ruminal