An increasing worldwide interest in alternative fuel sources and in a more diversified energy matrix has provided incentives for the biodiesel industry, generating large amounts of the by-product crude glycerin, a potential alternative feed for dairy cows. A replicated 3×3 Latin square study was conducted to evaluate the effects of high concentrations of crude glycerin on dry matter intake, milk yield and composition, milk fatty acid profile, and blood metabolites of medium-yield cows. Ruminally cannulated Holstein cows (n=6; 587 ± 39 kg of body weight; 114 ± 29 d in milk; and 20 ± 1.5 kg/d milk yield) were used in the study. The experimental period included 2 wk for adaptation and 1 wk for data collection. Cows were fed diets containing 0 (control), 15, or 30% crude glycerin (83% glycerol). Cows were milked, milk weights were recorded twice daily, and milk samples were collected for milk quality analyses at d 18 and 19 in each experimental period. Feeding cows with crude glycerin linearly decreased dry-matter intake, the 3.5% fat-corrected milk, and the solid-corrected milk yield. Hepatic enzymes were not affected by dietary treatments, except gamma-glutamyl transferase, which was decreased with the 15% crude glycerin diet. Serum glucose and albumin showed quadratic effect with increasing inclusion of crude glycerin. Plasma cholesterol as well as total protein linearly decreased with increasing inclusion of crude glycerin. Milk fat concentration and yield showed a quadratic effect of treatments. Solid yield decreased linearly with increasing inclusion of crude glycerin. Odd-chain fatty acids and conjugated linoleic acid in milk fat linearly increased with addition of crude glycerin in the diets. Together, these results suggest that crude glycerin has potential to replace corn; however, feeding diets in which corn is replaced with crude glycerin at 30% of dietary DM greatly reduces animal performance.
-Two studies were conducted to evaluate the effects of crude glycerin on feed intake, performance, carcass characteristics, and total digestibility of Nellore bulls. In experiment 1, cattle (n = 30) were fed a control diet without crude glycerin and diets containing 7.5, 15, 22.5, and 30% crude glycerin, for 103 d. Animals were harvested and data of carcass characteristics were collected. In experiment 2, a digestibility trial was performed using indigestible acid detergent fiber (iADF) as internal marker, and five rumen-cannulated steers. Both experiments were conducted as a randomized complete block design and data were analyzed using mixed procedures. In experiment 1 no differences were observed among treatments on dry matter intake, and performance variables. Regarding carcass characteristics, no effect was observed, except for carcass fat estimates, which were greater in treatments with crude glycerin. In experiment 2, crude glycerin promoted a decrease in digestibility of fibrous fractions NDF and HEM, and increased digestibility of crude protein by 6%. Although it caused negative effect on digestibility of fibrous fraction of diets, crude glycerin can be a good energy source for Nellore bulls, since no losses are observed on performance and carcass characteristics when animals are fed up to 30% of this by-product.
This study aimed to evaluate the effects of glycerin supplements in the diet of beef cattle by assessing intake, apparent nutrient digestibility, ruminal pH, ruminal ammonia concentrations, and blood parameters. The study was conducted at the São Paulo State University (UNESP, Jaboticabal campus) using five crossbred cattle in an experiment employing a 5 x 5 Latin square design. Cattle diet treatments included zero, 50, 100, 150, and 200 g kg -1 dry matter of glycerin. Feed, leftover feed, and faeces were collected to determine intake and digestibility. Samples of ruminal liquid were collected at -1, 0, 1, 2, 4, 6 and 8 h after feeding to determine pH and ruminal ammonia. Blood was collected four hours after the morning feeding from the coccygeal vein. Replacing maize with glycerin resulted in lower concentrations of ether extract and non-fibre carbohydrates in the diets, leading to a linear decrease in the intake of these nutrients (P<0.05). The digestibility of neutral detergent fibre and nonfibre carbohydrates also decreased linearly with increasing dietary glycerin concentrations (P<0.05). The results for ruminal fermentation parameters showed a linear decrease (P<0.05) in the ruminal concentration of N-NH 3 with increasing dietary levels of glycerin; however, ruminal pH was not affected (P>0.05). Serum concentrations of urea, triglycerides, cholesterol, and plasma glucose concentrations were within normal ranges based on the literature. The inclusion of glycerin in the cattle diet altered rumen fermentation, reducing the concentration of N-NH 3 , the digestibility of neutral detergent fiber and non-fiber carbohydrates. g kg -1 de glicerina na MS. Para determinação do consumo e digestibilidade foram realizadas colheitas de alimentos, sobras e fezes. Para determinação do pH e amônia ruminal foram colhidas amostras de líquido ruminal nos tempos -1, 0, 1, 2, 4, 6 e 8 horas após a alimentação. As colheitas de sangue foram realizadas 4h após a alimentação matutina via veia coccígea. A substituição do milho pela glicerina resultou em menores concentrações de extrato etéreo e carboidratos não fibrosos nas dietas, o que levou a redução linear no consumo desses nutrientes (P<0,05). As digestibilidades da fibra em detergente neutro e de carboidratos não fibrosos apresentaram redução linear com o aumento da concentração de glicerina na dieta (P<0,05). Em relação à fermentação ruminal, houve decréscimo linear (P<0,05) na concentração ruminal de N-NH 3 com o aumento da inclusão desse subproduto, mas o pH ruminal não foi influenciado (P>0,05). As concentrações séricas de ureia, triglicerídeos e colesterol ficaram dentro dos níveis considerados normais pela literatura assim como as concentrações plasmáticas de glicose. A inclusão de glicerina na dieta de bovinos alterou a fermentação ruminal, reduzindo a concentração de N-NH 3 , a digestibilidade da fibra em detergente neutro e dos carboidratos não fibrosos. Palavras-chave: Biodiesel, fermentação ruminal, metabolismo, subproduto
IntroduçãoNos últimos anos, a nutrição de vacas leiteiras tem recebido muita atenção, com ênfase na determinação dos requerimentos em energia e proteína, baseando-se nas frações protéicas degradáveis e não-degradáveis dos alimentos e nos requerimentos em aminoácidos. Efeito da Metionina Protegida e Não Protegida da Effect of Rumen Protected and Nonprotected Methionine on Milk Production and Composition of Dairy Holstein CowsABSTRACT -The purpose of this work was to evaluate the effect of 8.4 g/day of rumen protected methionine (RPM) or 8.4 g/ day of rumen non protected methionine (RNPM) or even of control cows on milk yield and compositon during 90 days of lactation. Six high yielding lactating Holsteins cows (>20 kg/day) in the first and second lactation, with 19 + 6 days of lactation were used in a duplicated latin square design. The cows were fed a total mixed ration composed of corn silage and concentrate. The milk production and the milk protein and yield were not affected by RPM or RNPM suplementation. The milk yield was 27.70; 27.09 and 27.61 kg/ day, the milk protein content was 2.83; 2.85 and 2.77% and the protein yield was 0.77; 0.76 and 0.79 kg/day for control cows, RPM and RNPM, respectively. The fat content was affected (P<.05) by RPM suplementation. The fat content was 2.39; 2.12 and 1.89 % for RPM, RNPM and control, respectively. Daily fat milk yield were 0.57; 0.58 and 0.58 and the 3.5% fat correct milk yield were 21.25; 21.19 and 21.35 kg/day, respectively for control, RPM and RNPM, respectively. The suplementation with RPM did not affect the milk yield, but improved milk fat content in early latctation cows. Os ruminantes necessitam de aminoácidos para as atividades de síntese de proteína em vários tecidos e síntese de produtos como leite, carne, lã etc. Podem também ser necessários para maximizar a eficiência do crescimento microbiano no rúmen.A quantidade e qualidade dos aminoácidos que chegam ao intestino delgado dos ruminantes resulta daqueles oriundos da proteína microbiana do rúmen e Rev. bras. zootec., 30(1):286-294, 2001
RESUMO -Foram utilizados quatro bovinos mestiços, castrados, canulados no rúmen com o objetivo de quantificar as bactérias e protozoários líquido-associados, as bactérias sólido-aderidas e relacioná-las com o pH ruminal de bovinos recebendo amiréia dietética (30% de uréia) no concentrado e silagem de milho. Realizaram-se três coletas de conteúdo ruminal, à 1h, às 2h30 e 11h30 após a alimentação. A massa microbiana foi quantificada e qualificada nas diferentes frações das bactérias sólido-aderidas (BSA), bactérias líquido-associadas (BLA) e protozoários líquido-associados (PLA) e seus teores de nitrogênio (N), de matéria seca (MS) e de matéria orgânica (MO), determinados. A população microbiana apresentou crescente contribuição das BSA no decorrer do tempo, o que não ocorreu com BLA e PLA. O teor de MO/MS das BSA também aumentou o tempo 2h30, permanecendo inalterado até 11h30. Os teores de nitrogênio das BSA expressos na matéria orgânica diminuíram em tempos de coleta iguais ou superiores a 2h30, embora os teores de N na matéria seca não apresentassem essa diferença. As relações entre bactéria:protozoário encontradas foram iguais a 1 : 2,1 à 1 h, 2,6: 1 às 2h30 e 2,2: 1 às 11h30 após a alimentação, quando foi observado predomínio de protozoários e bactérias, ambos associados ao líquido ruminal. As quantidades totais e as frações do "pool" microbiano ruminal não foram influenciadas pelo pH, provavelmente, porque este se manteve sempre acima de 6,39.Palavras-chave: matéria orgânica, matéria seca, microrganismos ruminais, nitrogênio Quantification of the Solid-Associated Bacteria and Liquid-Associated Bacteria and Protozoa from Rumen of Steers Fed with StareaABSTRACTS -It were utilized four crossbreed, castrated, rumen cannuladed bovines, receiving dietary starea (containing 30% of urea) in the concentrate and corn silage, with the objective of quantify the liquid-associated bacteria and protozoa, solid-associated bacteria and related them with the ruminal pH. Three samples from ruminal content were harvested at 1 a.m., 2 a.m. and 30 min and 11 a.m. and 30 min after feeding. The microbial mass was quantified and qualified in the different fractions of solid-associated bacteria (SAB), liquid-associated bacteria (LAB) and liquid-associated protozoa (LAP) and their nitrogen contents (N), dry matter (DM) and organic matter (OM) were determined. The microbial population presented increasing contribution of SAB with the time, what did not occur with LAB and LAP. The level of OM in DM from the SAB increased as well, until 2 a.m. and 30 min when remains unaffected until 11 a.m. and 30 min. The nitrogen levels of the SAB expressed in the organic matter decreased in equal or superior time of harvest at 2 a.m. and 30 min, although the N level in the dry matter did not present this difference. The relations between bacteria:protozoa were equal to 1: 2.1 at 1 hour, 2.6: 1 at 2h and 30 min and 2.2: 1 at 11h and 30 min after the feeding. It was still observed after feeding prevalence of protozoa and bacteria, both associated to th...
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