Effect of using Acacia mearnsii tannin extract as a feed additive on nutritional variables and productive performance in dairy cows grazing a temperate pasture

• Published in: Animal science journal Vol. 91; no. 1; pp. e13407 - n/a
• Main Authors: Orlandi, Tiago, Pozo, Claudio A., Schiavo, Jordana, Oliveira, Lisandre, Kozloski, Gilberto V.
• Format: Journal Article
• Language: English
• Published: Australia Blackwell Publishing Ltd 01.01.2020
• Subjects: Acacia - chemistry; Acacia mearnsii; Animal Feed; Animal Nutritional Physiological Phenomena - drug effects; Animal Nutritional Physiological Phenomena - physiology; Animals; Cattle - metabolism; Cattle - physiology; Dairy cattle; dairy cows; Dairying; Diet; Diet - veterinary; Dietary Supplements; Dry matter; Eating; Excretion; Feed additives; Female; Grazing; Herbivory; Lactation - metabolism; Milk; Milk - chemistry; Milk production; N utilization; Nitrogen; Nitrogen - metabolism; Nutrition; Pasture; ryegrass; tannins; Tannins - administration & dosage; Tannins - isolation & purification; Tannins - pharmacology; Urea; Urine; milk production; N utilization; dairy cows; ryegrass; tannins
• ISSN: 1344-3941; 1740-0929
• DOI: 10.1111/asj.13407

This study was carried out to evaluate the impact of including Acacia mearnsii tannin extract (TA) as a feed additive on nutrition and productive performance of dairy cows grazing a high‐quality temperate pasture and receiving supplementation with a concentrate feedstuff. Fourteen multiparous Holstein cows were assigned to either of the following treatments: concentrate without or with 20 g TA/kg dry matter (DM). Concentrate intake accounted for 32% of the total DM intake. Tannin addition increased the herbage DM intake by 22% (p < .05). There was no effect of TA inclusion on milk yield, milk composition, milk nitrogen (N) excretion, milk and plasma urea‐N concentration, urinary excretion of total N, urea‐N, and purine derivatives. However, TA inclusion increased the N intake and retention, total N excretion in manure, fecal N to urine N ratio, and decreased the dietary N efficiency for milk production and the percentage of ingested N excreted in urine (p < .05). In conclusion, supplementing dairy cows grazing a high‐quality temperate pasture with a concentrate containing 20 g TA/kg DM showed the potential of decreasing the proportion of ingested N excreted in urine without affecting the productive performance.