title: Effect of quebracho-chestnut tannin extracts at 2 dietary crude protein levels on performance, rumen fermentation, and nitrogen partitioning in dairy cows.
abstract: Our objective was to determine the effects of a tannin mixture extract on lactating cow performance, rumen fermentation, and N partitioning, and whether responses were affected by dietary crude protein (CP). The experiment was conducted as a split-plot with 24 Holstein cows (mean ± standard deviation; 669±55kg of body weight; 87±36 d in milk; 8 ruminally cannulated) randomly assigned to a diet of [dry matter (DM) basis] 15.3 or 16.6% CP (whole plot) and 0, 0.45, 0.90, or 1.80% of a tannin mixture in three 4×4 Latin squares within each level of CP (sub-plot). Tannin extract mixture was from quebracho and chestnut trees (2:1 ratio). Dietary CP level did not influence responses to tannin supplementation. A linear decrease in DM intake (25.5 to 23.4kg/d) was found, as well as a linear increase in milk/DM intake (1.62 to 1.75) and a trend for a linear decrease in fat-and-protein-corrected milk (38.4 to 37.1kg/d) with increasing levels of tannin supplementation. In addition, there was a negative linear effect for milk urea N (14.0 to 12.9mg/dL), milk protein yield (1.20 to 1.15kg), and concentration (2.87 to 2.83%). Furthermore, the change in milk protein concentration tended to be quadratic, and predicted maximum was 2.89% for a tannin mixture fed at 0.47% of dietary DM. Tannin supplementation reduced ruminal NH3-N (11.3 to 8.8mg/dL), total branched-chain volatile fatty acid concentration (2.97 to 2.47mol/100mol), DM, organic matter, CP, and neutral detergent fiber digestibility. Dietary tannin had no effect on intake N (587±63g/d), milk N (175±32g/d), or N utilization efficiency (29.7±4.4%). However, feeding tannin extracts linearly increased fecal N excretion (214 to 256g/d), but reduced urinary N (213 to 177g/d) and urinary urea N (141 to 116g/d) excretion. Decreasing dietary CP did not influence milk production, but increased N utilization efficiency (milk N/N intake; 0.27 to 0.33), and decreased milk urea N (15.4 to 11.8mg/dL), ruminal NH3-N (11.0 to 9.3mg/dL), apparent digestibility of DM (66.1 to 62.6%), organic matter (68.2 to 64.3%), and CP (62.9 to 55.9%), as well as urinary N excretion (168 vs. 232g/d). Results of this study indicated beneficial effects of 0.45% tannin extract in the diet on milk protein content. Increasing tannin extract levels in the diet lowered urinary N excretion, but had detrimental effects on DM intake, milk protein content, milk protein yield, and nutrient digestibility.
authors.affiliation: Department of Dairy Science, University of Wisconsin, Madison 53706.
authors.forename: M J
authors.initials: MJ
authors.lastname: Aguerre
authors.affiliation: Estación Experimental INTA Reconquista, Reconquista, Argentina 3567.
authors.forename: M C
authors.initials: MC
authors.lastname: Capozzolo
authors.affiliation: Silvateam, Indunor S. A., Argentina 1010.
authors.forename: P
authors.initials: P
authors.lastname: Lencioni
authors.affiliation: Silvateam, Indunor S. A., Argentina 1010.
authors.forename: C
authors.initials: C
authors.lastname: Cabral
authors.affiliation: Department of Dairy Science, University of Wisconsin, Madison 53706. Electronic address: wattiaux@wisc.edu.
authors.forename: M A
authors.initials: MA
authors.lastname: Wattiaux
mesh_terms: D027926:Anacardiaceae / Q000737:chemistry*; D000821:Animal Feed / Q000032:analysis; D000824:Animal Nutritional Physiological Phenomena / Q000187:drug effects*; D000818:Animals; D002417:Cattle / Q000502:physiology*; D004032:Diet / Q000662:veterinary; D004044:Dietary Proteins / Q000378:metabolism; D019587:Dietary Supplements / Q000032:analysis; D004063:Digestion / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D029962:Fagaceae / Q000737:chemistry*; D005260:Female; D047348:Hydrolyzable Tannins / Q000008:administration & dosage*; D009584:Nitrogen / Q000652:urine; D010936:Plant Extracts / Q000008:administration & dosage; D044945:Proanthocyanidins / Q000008:administration & dosage*; D011897:Random Allocation; D012417:Rumen / Q000187:drug effects / Q000502:physiology
chemical_list: D004044:Dietary Proteins; D047348:Hydrolyzable Tannins; D010936:Plant Extracts; D044945:Proanthocyanidins; D009584:Nitrogen
keywords: dairy; nitrogen; protein; quebracho and chestnut tannins