Synchronization of Ruminal Degradation of Supplemental Carbohydrate with Pasture Nitrogen in Lactating Dairy Cows

• Published in: Journal of dairy science 1998-07, Vol.81 (7), p.2017-2028
• Main Authors: Kolver, E., Muller, L.D., Varga, G.A., Cassidy, T.J.
• Format: Article
• Language: English
• Subjects: ACIDE GRAS; ACIDE GRAS VOLATIL; ACIDO GRASO VOLATIL; ACIDOS GRASOS; ALIMENT CONCENTRE POUR ANIMAUX; AMMONIUM COMPOUNDS; AMMONIUM NITROGEN; Animal productions; Animals; AZUCAR EN SANGRE; Biological and medical sciences; BLOOD PLASMA; BLOOD SUGAR; Blood Urea Nitrogen; BODY WEIGHT; carbohydrate; Cattle - metabolism; CHOIX DE LA DATE; COMPOSE DE L'AMMONIUM; COMPUESTOS DE AMONIO; CONCENTRATES; CONTENIDO PROTEICO; CONTEO DE CELULAS SOMATICAS; DACTYLIS; DACTYLIS GLOMERATA; DAIRY COWS; Diet; Dietary Carbohydrates - metabolism; DIGESTIBILIDAD; DIGESTIBILITE; DIGESTIBILITY; Digestion; DIGESTION DU RUMEN; DIGESTION RUMINAL; DIURNAL ACTIVITY; EFFICACITE ALIMENTAIRE; EFICIENCIA DE CONVERSION DEL PIENSO; ELECCION DE LA EPOCA; FATTY ACIDS; FEED CONVERSION EFFICIENCY; FEED INTAKE; FEEDING FREQUENCY; Female; Fermentation; FLUIDE DU RUMEN; FLUIDO DEL RUMEN; FORRAJE VERDE; FOURRAGE VERT; FRECUENCIA DE LAS COMIDAS; FREQUENCE DES REPAS; Fundamental and applied biological sciences. Psychology; GAIN DE POIDS; GANANCIA DE PESO; GRASA DE LA LECHE; GREEN FEED; GREEN FODDERS; Hydrogen-Ion Concentration; INGESTION DE PIENSOS; Kinetics; LACTACION; LACTATION; LIVEWEIGHT GAIN; MAIS; MAIZ; MAIZE; MATIERE GRASSE DU LAIT; METABOLISME DE L'AZOTE; METABOLISMO DEL NITROGENO; MILK FAT; MILK PROTEIN; MILK YIELD; nitrogen; NITROGEN BALANCE; NITROGEN METABOLISM; NITROGEN RETENTION; NUMERATION CELLULAIRE SOMATIQUE; pasture; PESO CORPORAL; PIENSOS CONCENTRADOS; PLASMA SANGUIN; PLASMA SANGUINEO; POA PRATENSIS; POIDS CORPOREL; PRISE ALIMENTAIRE (ANIMAUX); PROTEIN CONTENT; PROTEINAS DE LA LECHE; PROTEINE DU LAIT; RENDEMENT LAITIER; RENDIMIENTO LECHERO; RETENCION NITROGENADA; RETENTION AZOTEE; Rumen - metabolism; RUMEN DIGESTION; RUMEN FLUID; SOMATIC CELL COUNT; SUCRE DU SANG; TENEUR EN PROTEINES; Terrestrial animal productions; Time Factors; TIMING; UREA; UREE; VACAS LECHERAS; VACHE LAITIERE; Vertebrates; VOLATILE FATTY ACIDS; WEIGHT GAIN
• ISSN: 0022-0302; 1525-3198
• DOI: 10.3168/jds.S0022-0302(98)75776-5

Twelve Holstein cows in early to midlactation (8 fitted with ruminal cannulas) were used to test the hypothesis that the synchronization of the rate of ruminal degradation of supplemental carbohydrate and N from fresh pasture would increase the amount of N retained for growth and milk production. A concentrate based on ground shelled corn was fed either at the time that pasture was fed at 0900 and 1700h (synchronous) or 4h after pasture was fed at 1300 and 2100h (asynchronous). The crossover design included a 6-d adjustment period and a 10-d milk sampling period. Nitrogen balance was determined during the last 5 d of each period. Cows fed the synchronous diet had a lower mean ruminal pH. Peak ammonia concentration at 3 and 5h after pasture feeding in the morning was reduced by approximately 33% of values obtained from cows fed the asynchronous diet. The diurnal pattern of blood urea N concentration was similar to that of ruminal ammonia, but mean daily concentrations of blood urea N did not differ between diets. Nitrogen retained for milk production and growth was not influenced by diet, and no differences in milk production, composition, or efficiency were observed. Based on changes in ruminal concentrations of ammonia, synchronous ruminal release of supplemental carbohydrate with pasture N appeared to improve the capture of ruminal N; however, these changes were transient and did not change the N status or performance of dairy cows.