CHARACTERISTICS OF DIGESTION IN HIGH-PRODUCING COWS: DEPENDENCE ON THE FAT CONСENTRATION IN THE RATION DRY MATTER (original) (raw)
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Influence of different fat supplements on digestibility and ruminal digestion in cows
Annales de Zootechnie, 1991
— In two trials each using 3 cows fitted with, rument cannulas, the effects of different lipid supplements on digestibility and ruminal digestion were analyzed. In trial 1, a control diet based on maize silage (Ci) was compared to the same diet with a supplement of crude (untreated) bone fat (UF) and with a crystalline animal fat (CF). In trial 2, a control diet (C2) similar to diet C1 was compared to the same diet with a supplement of protein-coated (encapsulated) fat (EF). Fatty acid content in dry matter was 2.5% for control diets, 8.1 to 9.1 % for supplemented diets. Apparent digestibility of nutrients, pH and volatile fatty acids in rumen juice, in sacco degradability of dry matter and cell walls were determined. Fat supply decreased organic matter digestibility in trial 1 (76.4, 67.8 and 68.8% in diets C1, UF and CF) and in trial 2 (74.1 and 68.1 % in diets C2 and EF). This decrease was due to a strongly negative action on cell wall digestion: 69.1, 53.7% and 57.3 in diets C1, UF and CF, 62.9 and 53.6% in diets C2 and EF, for NDF digestibility, and was related to a decrease in total volatile fatty acid concentration before feeding: 67.4, 46.7 and 47.7 mM in diets C1, UF and CF, 61.1 and 54.6 mM in diets C2 and EF. Acetate and butyrate decreased and propionate increased with lipid supply. The negative effect of fat on in sacco dry matter and cell wall degradation was moderate. cow I digestion I "protected" fats Résumé — Influence de différents suppléments lipidiques sur la digestibilité et la digestion ruminale chez la vache. Deux essais ont été menés, chacun avec 3 vaches porteuses de fistules du rumen, en vue d'analyser les effets de différents suppléments lipidiques sur la digestion. Dans l'essai 1, un régime témoin à base d'ensilage de maïs (T I) a été comparé au même régime avec une supplémentation en graisse d'os de bovins non traitée technologiquement (LNT) ou en graisses animales cristallisées (LC). Dans l'essai 2, un régime témoin (T 2) proche du régime T l a été comparé au même régime additionné de graisses animales et d'huiles végétales encapsulées par une coque protéique (LE). Les teneurs en acides gras totaux dans la matière sèche étaient de 2,5°/ pour les régimes témoins et comprises entre 8,1 1 et 9,1 % pour les régimes expérimentaux. Dans ces essais, la digestibilité de différents nutriments ainsi que le pH, la concentration et la composition des acides gras volatils du liquide du rumen et la dégradation in sacco de la matière sèche et des parois végétales ont été mesurés. La supplémentation lipidique a réduit la digestibilité de la matière organique, qui a été respectivement pour l'essai 1 de 76,4; 67,8 et 68,8°/ (régimes T l , LNT et LC) et pour l'essai 2 de 74,1 et 68, 1 % (régimes T 2 et LE). Cette diminution a été due à une action très négative des lipides sur la digestion des parois végétales : la digestibilité du NDF a été de 69 1.; 53 7 et 57,3% (régimes T I LNT et LC); 62,9 et 53,6°/ (régimes T 2 et LE). Cette diminution est liée!à celle de la concentration en acides gras volatils dans le liquide du rumen, mesurée avant repas : 67,4; 46,7 et 47,7 mmo/.r ' ' pour les régimes T l , LNT et LC; 61,1 et 54,6 mmo/.r-' pour les régimes T 2 et LE. Les proportions d'acétate et de butyrate diminuent et celle de propionate augmente avec la supplémentation lipidique. En revanche, celle-ci n'a qu'un léger effet négatif sur la dégradation de la matière sèche et des parois végétales in sacco. vache / digestion / lipides «protégés»
Concepts in Lipid Digestion and Metabolism in Dairy Cows
2006
Fat and fatty acid metabolism and digestion in the dairy cow are of considerable interest, both to scientists and the dairy industry. This renewed interest is based on several reasons; first, the use of dietary fat supplements has increased, and will continue to do so, as nutritionists strive to increase the energy density of diets to meet requirements of the high producing dairy cow; second, we now recognize that fatty acids, both of dietary and rumen origin, can have specific and potent effects on ruminant metabolism and human health; and third, we now recognize that specific fatty acids produced in the rumen are potent regulators of milk fat synthesis in the mammary gland. Our objective in this review is to provide an overview of lipid metabolism in the dairy cow. Our focus will include the biological processes and quantitative changes occurring during the metabolism of fatty acids in the rumen and their subsequent absorption in the small intestine. In addition, we will discuss t...
Fat addition in the diet of dairy ruminants and its effects on productive parameters
Revista Colombiana de Ciencias Pecuarias
Esta revisión examina la información actual sobre el efecto de añadir fuentes de grasa a la dieta de hembras rumiantes lecheras. Estudios con vacas y cabras han demostrado que el consumo de materia seca se reduce cuando la grasa extra incluida en la dieta tiene un efecto negativo sobre la digestibilidad. En vacas, el consumo también puede reducirse por efecto de la grasa extra sobre la secreción de mediadores hormonales en el intestino. Este efecto no ha sido demostrado en ovejas y cabras. En vacas, ovejas y cabras, la respuesta de la producción de leche a la inclusión de cantidades crecientes de lípidos suplementarios en la dieta es curvilínea: cuando el aporte de grasa es bajo, el incremento de la producción puede explicarse por un mayor consumo de energía. Por el contrario, la disminución de la producción cuando el consumo de grasa es elevado puede relacionarse con la reducción de la energía disponible debido al efecto negativo sobre la digestión ruminal y/o el consumo de materia...
Ruminal Synthesis, Biohydrogenation, and Digestibility of Fatty Acids by Dairy Cows1
Journal of Dairy Science, 1991
Ruminal synthesis and biohydrogenation of fatty acids in dairy cows were determined by sampling duodenal digesta through T-cannulas. Fatty acid digestibility in the total tract also was measured. Five diets (concentrate:alfalfa hay:alfalfa haylage:corn silage, 2:1:1:1, DM) in a 5 × 5 Latin square contained either no added fat; 3 or 6% added calcium soap; or 3 or 6% animal-vegetable blend fat. Seventy percent of dietary fatty acids were recovered at the duodenum, and 106 g/d were synthesized in the rumen regardless of diets. Fatty acids synthesized in greatest amounts were odd or branched chains, whereas more than 90% of the fatty acids shorter than 14 carbons disappeared. Fatty acids in calcium soap were biohydrogenated 57% and in animal-vegetable blend 87%. Fatty acids in calcium soap were more digestible (80.0 vs. 75.7%) than those in the blended fat due to greater unsaturation in the small intestine. Ruminal microorganisms selectively synthesized fatty acids.
Italian Journal of Animal Science, 2010
The recent literature dealing with the effect of the diet on the quality of milk and meat fat is reviewed. Some aspects of the rumen metabolism of lipids are dealt with: lipolysis, bio-hydrogenation, synthesis of microbial fatty acids and inhibition mechanisms on fermentation. Firstly, the influence of forage is considered. Pasture is the best forage, better if high hill pasture, as compared to hay and silage: short chain fatty acids (SCFA) (shorter than C10) are increased, medium chain fatty acids (MCFA) (C12 through C16) are decreased, oleic (OA), linoleic (LA) and linolenic (LNA) acids are increased and so are the conjugated linoleic acid pool of isomers (CLA) and n-3 polyunsaturated fatty acids (n-3 PUFA). Secondly, the energy supplementation of diets with fats is looked at. Animal fats depress milk yield and SCFA, while OA is increased because of the enhanced activity of mammary ∆ 9 desaturase. Fish oil depresses milk yield as well, but promotes CLA and n-3 PUFA. If animal fats are protected against rumen bacteria, milk yield and milk fat depression are avoided. Vegetable fats are richer in unsaturated fatty acids (UFA), thus more susceptible to the rumen bio-hydrogenation. As calcium soaps or inside whole seeds, plant fats are protected and CLA is increased. CLA is an important component of fat. In ruminants it comes from the desaturation of vaccenic acid (VA) both in rumen and udder; and the yield of VA depends on the diet quality. In conclusion, simple directions are given on how to improve the quality of animal fat by dietary means, without affecting yield.
Scientific progress in ruminant production in the 1st decade of the XXI century
Revista Brasileira De Zootecnia-brazilian Journal of Animal Science, 2010
Scientific advances in nutrition of dairy cows in the first decade of the XXI century have occurred. This paper will review the most common additives fed to transition cows to decrease the incidence of metabolic disorders, which will be discussed separately with emphasis on their mechanisms of action, utilization and efficiency. Some changes on protein in the 2001 updated version of the Nutrient Requirements of Dairy Cattle to reach better precision of the nitrogen and amino acid requirements of lactating cows also are presented. Many of the advances in nutritional manipulation of milk fat concentration are related to fat supplementation, then the relationship between the action of rumen microbes on biohydrogenation of dietary polyunsaturated fatty acids and milk fatty acid profile are discussed as well as the main factors identified as being responsible for milk fat depression.
Revista Brasileira de Zootecnia, 2013
The objective of the present study was to evaluate the effects of dietary lipid content (20, 40 and 60 g/kg dry matter) on intake, total and ruminal apparent digestibility of dry matter (DM), nutrient digestibility, rumen fermentation parameters, microbial synthesis efficiency and rumen microbial content of beef cattle. Nine cannulated steers at 6 months of age with initial body weight of 232±35 kg were used in a triplicate 3 × 3 Latin square design. The results indicated that the total intake and digestibility of DM, organic matter (OM), gross energy (GE), neutral detergent fiber (NDF) and acid detergent fiber (ADF) were not affected by the lipid content of the diet. However, the lowest lipid content diet reduced the total digestibility of crude protein (CP) and total carbohydrate linearly compared with the highest lipid diet. In contrast, when steers were fed a diet containing 20 g lipids/kg of DM, the concentration of ammonia in the rumen decreased quadratically relative to the other diets. Ruminal pH was not affected by the interaction of treatment and sampling time; however, the rumen pH decreased quadratically in animals that received the highest dietary lipid content (60 g/kg) compared with animals that received 20 and 40 g lipids/kg of DM. The rumen concentrations of volatile fatty acids, propionate, and butyrate and the acetate/propionate ratio were affected by the dietary lipid content. However, the microbial population, microbial N flow, and efficiency of synthesis were not affected by dietary lipid content. Overall, an increase in the lipid content of the diet of Nellore steers resulted in similar digestive profiles and fermentation conditions.
Digestion and metabolism of dietary fat in farm animals
British Journal of Nutrition, 1997
Fat digestion and metabolism differ widely between animal species. In ruminants, dietary fats are hydrogenated in the rumen before intestinal absorption so that absorbed fatty acids (FA) are more saturated than dietary FA. In non-ruminants, intestinal FA digestibility depends on the level of saturation of dietary FA. Fat supplementation of the diet of cows decreases milk protein and has a variable effect on milk fat, depending on the source of dietary lipids. When encapsulated lipids are used, the linoleic acid content of milk is increased, but the organoleptic quality of milk may be altered. Supplementary lipids are incorporated into non-ruminant body fat, whereas de novo lipogenesis is reduced. There is a close relationship between the nature of dietary FA and non-ruminant body FA.