The effect of ensiled paulownia leaves in a high-forage diet on ruminal fermentation, methane production, fatty acid composition, and milk production performance of dairy cows

Table 1 Ingredients and chemical composition of experimental diets (n = 4) used in Rusitec system and in vivo experimets^a and chemical composition of paulownia leaves silage (PLS; n = 4) and alfalfa silage (AS; n = 4)

Item	PLS	AS	Treatments^b
			CON	PLS, g/kg DM
			CON	20	40	60
Ingredient composition, g/kg DM
Corn silage	-	-	388	385	386	386
Alfalfa silage	-	-	82	68	47	26
Paulownia silage	-	-	0	21	39	60
Meadow grass silage	-	-	91	90	90	90
Beet pulp	-	-	103	103	103	103
Brewer’s grain	-	-	95	94	95	95
Concentrate^c	-	-	119	118	119	119
Rapeseed meal	-	-	108	107	107	107
Mineral and vitamin premix^d	-	-	14	14	14	14
Forage to concentrate ratio	-	-	76:24	76:24	76:24	76:24
Chemical composition^e, g/kg DM
DM, g/kg as fed	279	299	425	423	422	419
OM	869	874	909	907	904	900
aNDF	359	350	347	346	349	351
CP	174	218	161	160	158	158
EE	27.5	20.0	27.1	29.8	30.5	29.5
Total phenolic compounds^f	60.0	-	0.00	1.20	2.40	3.60
VEM^g	785	667	948	945	943	942
Fatty acid composition, g/100 g total FA
C12:0	0.19	2.18	0.31	0.24	0.31	0.31
C14:0	0.71	1.90	0.47	0.40	0.50	0.48
C16:0	27.4	26.5	22.3	21.3	21.2	21.5
C16:1 cis-9	3.89	1.36	0.74	0.78	1.03	0.99
C18:0	4.16	4.01	2.63	2.55	2.16	2.82
C18:1 cis-9	5.26	4.76	20.3	19.7	18.9	17.8
C18:2 cis-9.cis-12	16.2	20.4	44.4	45.2	44.6	44.7
C18:3 cis-9.cis-12.cis-15	42.2	38.8	8.85	9.83	11.3	11.4

^aIn the in vitro experiments the diets were as a total mixed ration (TMR)
^bCON control diet, PLS paulownia leaves silage diet, PLS was used at 20, 40 and 60 g/kg DM of diet replacing alfalfa silage
^cDeclared to contain (as g/kg of DM in concentrate) OM (910), aNDFom (240), CP (17.5), and EE (31)
^dDeclared to contain (g/kg of DM) Na (123), Ca (100), Mg (45), P (42), K (20), S (18), Co (14), Cu (5.0), Zn (2.8), Mn (1.4), Fe (1.05), F (0.42), I (0.028), Se (0.018), biotin (0.008); (IU/kg), vitamin A (200,000), vitamin D₃ (40,000), and vitamin E (1200)
^eDM dry matter, OM organic matter, aNDF neutral detergent fiber analyzed with α-amylase, CP crude protein, EE: ether extract. Additionally, in the case of PLS and AS, the following fermentation parameters were performed: pH, 4.75 vs. 4.50; NH₃-N, 79.4 vs. 32.3 g/kg total nitrogen; lactic acid, 21.2 vs. 34.9 g/kg DM; acetic acid, 7.04 vs. 19.1 g/kg DM; propionic acid, 1.29 vs. 1.09 g/kg DM; butyric acid, 1.19 vs. 2.43 g/kg DM, respectively
^fThe content of total phenolic compounds have been calculated based on previous study of Huang et al. [4]
^gVEM = feed unit net energy lactation; calculated using the FeedExpert software

ISSN: 2049-1891