Dietary fiber and milk yield, mastication, digestion, and rate of passage in goats fed alfalfa hay

• Published in: Journal of dairy science Vol. 75; no. 1; pp. 209 - 219
• Main Authors: Santini, F.J. (INTA, Balcarce, Argentina), Lus, C.D, Potchoiba, M.J, Fernandez, J.M
• Format: Journal Article
• Language: English
• Published: Savoy, IL Am Dairy Sci Assoc 01.01.1992; American Dairy Science Association
• Subjects: 3-Hydroxybutyric Acid; ALFALFA; ALIMENT CONCENTRE; ALIMENTOS CONCENTRADOS; Ammonia - analysis; Animals; Biological and medical sciences; Blood Glucose - analysis; CAPRIN; CAPRINOS; CONTENIDO DE MATERIA SECA; Dietary Fiber - administration & dosage; DIGESTIBILIDAD; DIGESTIBILITE; DIGESTION; Eating - physiology; Energy Intake - physiology; Energy Metabolism; Female; FIBRA DE LA DIETA; FIBRE ALIMENTAIRE; FOIN; Food industries; Fundamental and applied biological sciences. Psychology; Gastrointestinal Transit; Goats - physiology; GRASA DE LA LECHE; HENO; Hydrogen-Ion Concentration; Hydroxybutyrates - blood; INGESTION DE PIENSO; Lactation - physiology; Lipids - analysis; LUZERNE; MASTICACION; MASTICATION; MATIERE GRASSE DU LAIT; Medicago sativa; Milk - analysis; Milk - secretion; Milk and cheese industries. Ice creams; PESO; PLASMA SANGUIN; PLASMA SANGUINEO; POIDS; PRISE ALIMENTAIRE (ANIMAUX); Random Allocation; RENDEMENT LAITIER; RENDIMIENTO LECHERO; RUMEN; Rumen - chemistry; Rumen - physiology; TENEUR EN MATIERE SECHE; Transit time; Lipids; Chewing; Vertebrata; Mammalia; Diet; Production; Goat; Artiodactyla; Dietary fiber; Lucerne; Ungulata; Digestibility; Milk
• DOI: 10.3168/jds.S0022-0302(92)77755-8
• ISSN: 0022-0302

Two experiments were conducted to study the effect of intake of fiber on productive performance of high producing dairy goats during early to midlactation. Four dietary treatments were isonitrogenous and consisted of combinations of chopped alfalfa hay and concentrate, yielding 14, 18, 22, and 26% ADF. In Experiment 1, 40 multiparous Alpine does were used in a completely randomized block design. Milk fat content and total chewing time increased, and milk yield tended to decrease, as dietary ADF intake increased. Chewing efficiency [min/(g X kg BW(.75))] for DM decreased, whereas that for ADF increased as ADF intake increased. Prediction equations were the following: milk fat yield, g/d = 115.78 - 0.128 X ADF intake, g/d + 0.00021 x (ADF intake)2 (r = 0.55); total chewing time, min/d = 345.33 + 0.32 x ADF intake, g/d (r = 0.60). In Experiment 2, 20 does were used in a completely randomized design. Apparent digestibilities of DM and energy decreased as dietary ADF intake increased. Rumen turnover rate and transit time of liquid were affected by ADF intake. Transit time of hay decreased as ADF intake increased. Intake of ADF affected pH and ammonia, acetate, and butyrate concentrations in the rumen. Acetate to propionate ratio increased with ADF intake. No apparent trends were observed in whole blood beta-hydroxybutyrate or in plasma NEFA concentrations related to ADF intake. It appeared that DMI and milk fat yield leveled at 22% ADF or 43% NDF. For lactating dairy goats producing more than 3.5 kg/d of milk, calculated fat output reached a plateau when they consumed 587 g/d of ADF and spent 512 min/d chewing