Nitrogen partitioning and microbial protein synthesis in lactating dairy cows with different phenotypic residual feed intake

Table 1 Ingredient composition of the total mixed rations

Ingredient	% (DM basis)	Nutrient levels^a	% of DM
Alfalfa hay	16.1	DM	51.8
Oat hay	7.55	OM	95.5
Corn silage	18.8	CP	16.0
Brewer’s grains	3.47	NDF	32.9
Beet pulp	4.67	ADF	19.0
Cottonseed meal, whole	5.49	NE_L, Mcal/kg DM	1.70
Steam-flaked corn	5.57
Ground corn grain	17.0
Soybean meal	9.62
Expanded soybean	2.74
Fat meal	1.09
DDGS^b	4.62
CaHPO₄	0.11
NaCl	0.21
Limestone	0.36
NaHCO₃	0.34
MgO	0.13
Premix^c	2.12

^aDM dry matter, OM organic matter, CP crude protein, NDF neutral detergent fiber, ADF acid detergent fiber, NE_L, net energy for lactation, estimated according to the NRC recommendation [13]
^bDGGS Distillers Dried Grains with Solubles
^cPremix, formulated to provide (per kg of DM): vitamin A ≥ 600 kIU, vitamin D₃ ≥ 150 kIU, vitamin E ≥ 2,000 IU, nicotinic acid ≥500 mg, Cu ≥ 1500 mg, Fe ≥ 1,500 mg, Mn ≥ 1,500 mg, Zn ≥ 7,000 mg, I ≥ 90 mg, Se ≥ 50 mg, Co ≥ 20 mg

ISSN: 2049-1891