. 2019 Mar 25;97(5):2230–2244. doi: 10.1093/jas/skz101

Table 4.

Effects of different forms of hydrolyzable tannin on N intake, excretion, and retention, and urinary N fractions of heifers (n = 8) fed an alfalfa silage-based high forage diet

	Treatment¹
Item²	Control	GA	TA	CN	SEM	P
N intake, g/d	335	336	352	340	35.4	0.53
Microbial N flow³, g/d	93	91	96	83	15.3	0.19
Output
Feces, kg DM/d	4.07^c	4.20^bc	4.59^a	4.39^ab	0.42	0.02
Urine, L/d	23.1	22.2	22.0	21.3	1.23	0.15
N excretion, g/d
Feces	102^c	106^c	134^a	124^b	13.1	<0.001
Urine	168	181	166	167	25.5	0.24
Total	270^y	287^xy	300^x	291^xy	38.3	0.07
N excretion, % of total N excretion
Feces	38.3^b	37.3^b	44.7^a	43.1^a	1.05	<0.001
Urine	61.7^a	62.7^a	55.3^b	56.9^b	1.05	<0.001
N excretion, % of N intake
Feces	30.3^b	31.7^b	37.8^a	36.8^a	0.09	<0.001
Urine	49.3^b	53.5^a	46.8^b	48.6^b	0.03	0.02
Urinary N fraction, g/d
Urea-N	82.8	85.2	78.1	77.1	9.23	0.15
Allantoin N	21.8	22.2	22.5	20.3	2.97	0.20
Uric acid N	2.28^a	1.57^b	2.21^a	2.02^a	0.21	<0.001
Urinary N fraction, % of urine N
Urea-N	51.2^a	47.8^b	47.4^b	46.5^b	2.03	0.02
Allantoin N	13.1	12.3	13.6	12.4	0.60	0.13
Uric acid N	1.32^a	0.91^b	1.36^a	1.26^a	0.12	<0.001
N retention
g/d	65.0	50.1	52.7	48.8	7.59	0.30
% of N intake	20.4	15.0	15.4	14.5	0.03	0.21
N retention, % N digested	29.0	21.9	24.6	22.6	4.27	0.28

^{a–c, x–y}Within a row, means without a common superscript letter differ or tend to differ at P < 0.05 or 0.05 ≤ P < 0.10, respectively.

¹GA = gallic acid; TA = tannic acid; CN = chestnut.

²Nitrogen intakes and excretion were sampled over 4 d and averaged before analysis.

³Estimated based on Allantoin N and uric acid N (Chen and Gomes, 1992).