Table 3.

Urine and fecal output, excretion of nitrogen (N) in urine, excretion of N and tannins in feces, N intake and retention, and blood urea N for cows and heifers

	Forage source1
	Tannin-containing hays			Non-tannin-containing hays
Item	BFT	SAN	SML	ALF	CMV	MB	SEM	P-value
Experiment 1: cows (n = 3 cows/forage source)
Urine output, L/d	13.3b	10.4b	10.7b	13.2b	18.9a	12.0b	1.94	0.074
Fecal output, g of dry matter/kg of body weight	4.9	5.3	6.2	5.8	4.5	4.0	0.78	0.440
Total N in urine, g/d	58.4d	90.9c	29.4e	180.1a	112.4b	56.5d	8.92	<0.001
Total N in urine, g/L of urine	4.7c	8.9b	2.3d	13.8a	6.5c	4.9c	0.87	<0.001
Total N in feces, g/d	52.7cd	75.3b	152.6a	90.7b	70.6bc	42.2d	11.24	0.001
Urine urea N, g/d	36.0b	45.2b	11.3c	101.1a	102.2a	39.3b	12.56	<0.001
Blood urea N, mg/dL	7.8c	11.5b	2.8d	15.2a	16.0a	8.2c	1.26	<0.001
N from urea, % of total urinary N	61.6bc	49.7cd	37.1d	55.4bc	89.9a	69.2b	7.54	0.006
N intake, g/d	247.3b	197.7c	182.3c	329.5a	332.5a	100.3d	11.93	<0.001
N retention, g/d	132.5b	37.7d	18.9e	58.5c	158.5a	9.7e	6.10	<0.001
Total N excreted, g/d	111.1c	166.2b	182.0b	283.1a	182.9b	98.6c	14.41	<0.001
Total N excreted, % of ingested N	45.5c	81.6b	90.2ab	82.8ab	53.4c	91.1a	3.48	<0.001
Excretion of condensed tannins in the feces
Tannins excreted in feces2, %	0.90c	1.45b	1.84a	0.41e	0.64d	0.35e	0.12	<0.001
Tannins excreted in feces, g/d	27.9c	47.7b	82.2a	14.6d	18.1cd	9.4e	5.78	<0.001
Experiment 2: heifers (n = 3 heifers/forage source)
Urine output, L/d	17.7ab	5.7d	11.3c	14.8bc	20.8a	6.4d	1.71	<0.001
Fecal output, g of dry matter/kg of body weight	7.8bc	6.3cd	7.5bcd	9.8a	5.9d	9.2ab	0.78	0.020
Total N in urine, g/d	66.1c	47.8d	17.1f	138.8a	103.2b	29.4e	7.48	<0.001
Total N in urine, g/L of urine	3.9c	8.3ab	1.6d	10.0a	4.9bc	5.1bc	1.41	0.001
Total N in feces, g/d	80.3c	92.6b	102.5a	108.7a	74.5c	46.1d	4.26	<0.001
Urine urea N, g/d	54.3b	21.7c	12.0d	104.9a	82.9a	15.5d	7.62	<0.001
Blood urea N, mg/dL	14.2b	14.2b	2.8d	22.9a	19.5a	9.5c	1.38	<0.001
N from urea, % of total urinary N	77.7	48.6	69.0	78.9	85.2	52.8	10.48	0.147
N intake, g/d	231.4b	203.2b	127.2c	333.8a	287.3a	93.8d	19.76	<0.001
N retention, g/d	88.7ab	72.7b	10.5c	89.6ab	112.5a	16.4c	9.67	<0.001
Total N excreted, g/d	145.6c	138.7c	121.3d	248.6a	177.8b	75.8e	9.93	<0.001
Total N excreted, % of ingested N	61.6c	65.8c	90.4a	74.8b	62.0c	81.5b	3.45	<0.001
Excretion of tannins in the feces
Tannins excreted in feces2, %	1.23b	1.94a	1.73a	0.31d	0.49c	0.30d	0.13	<0.001
Tannins excreted in feces, g/d	43.1c	70.6a	59.7b	14.4d	13.9d	9.7e	7.60	<0.001

^a–fMeans in the same row with different superscripts differ (P ≤ 0.10).

¹Treatment: alfalfa (ALF), birdsfoot trefoil (BFT), cicer milkvetch (CMV), meadow bromegrass (MB), sainfoin (SAN), and small burnet (SML).

²Tannins excreted in the feces as a percentage of fecal dry matter output.