Table 4.

Effects of increasing mammary glucose supply on the AA uptake to output ratio in the mammary gland of lactating dairy goats¹

Item2	Infused glucose, g/d						SEM	P-value
	0	20	40	60	80	100		Linear	Quadratic	Cubic
Essential AA
Arg	2.79	2.85	2.50	3.86	3.22	2.19	1.32	0.87	0.52	0.59
His	2.77	1.73	2.26	3.14	3.86	1.71	1.03	0.92	0.55	0.12
Ile	2.29	2.51	2.65	3.72	2.24	1.87	0.74	0.55	0.22	0.47
Leu	1.04	1.19	1.38	1.43	1.21	1.19	0.12	0.37	0.04	0.69
Lys	1.09	1.14	1.74	1.88	1.43	1.19	0.16	0.33	< 0.01	0.16
Met	1.00	1.13	1.45	1.97	1.47	1.00	0.31	0.91	0.04	0.70
Phe	1.05	1.14	1.16	1.23	1.02	1.09	0.31	0.95	0.68	0.77
Thr	1.01	1.19	1.15	1.11	1.32	1.25	0.14	0.88	0.29	0.52
Val	1.32	1.33	1.42	1.54	1.57	1.34	0.11	0.95	0.30	0.44
Non-essential AA
Ala	1.50	1.30	1.36	1.09	1.03	1.07	0.35	0.13	0.73	0.85
Asx	0.25	0.12	0.14	0.12	0.32	0.12	0.11	0.86	0.96	0.34
Cys	1.49	1.65	1.97	2.21	1.96	1.56	0.15	0.67	< 0.01	0.21
Glx	0.63	0.76	1.13	1.14	0.95	0.63	0.12	0.43	< 0.01	0.87
Gly	0.96	0.75	0.99	0.83	1.17	0.95	0.25	0.53	0.34	0.84
Pro	0.66	0.74	0.72	0.58	0.90	0.63	0.32	0.69	0.86	0.55
Ser	0.88	1.03	1.30	1.10	0.89	0.91	0.23	0.73	0.29	0.71
Tyr	1.20	1.24	1.16	1.13	1.04	1.07	0.28	0.89	0.34	0.85
Essential AA	1.38	1.44	1.62	1.86	1.65	1.35	0.14	0.82	0.02	0.57
Non-essential AA	1.74	1.81	1.13	1.46	1.38	1.82	0.39	0.78	0.40	0.62
Group-1 AA	1.35	1.27	1.40	1.59	1.55	1.17	0.47	0.73	0.73	0.41
Group-2 AA	1.36	1.48	1.65	1.87	1.60	1.38	0.13	0.59	< 0.01	0.65
Branched-chain AA	1.38	1.50	1.67	1.89	1.55	1.38	0.38	0.87	0.10	0.78
Total AA	1.06	1.11	1.28	1.33	1.23	1.00	0.31	0.90	0.22	0.74

¹ AA uptake to output ratio = Mammary gland uptake of AA (mmol/d)/[AA output in milk (mmol/d)]

² Glx: glutamate + glutamine; Asx: aspartate + asparagines; Group-1 AA: His, Met, Phe, and Tyr; Group-2 AA: Arg, Ile, Leu, Lys, Thr, and Val; Branched-chain AA: Ile, Leu, and Val