Table 3.

Grazing rotation intervals (mean ± SD), compressed pre-grazing herbage height, herbage dry matter intake (DMI), supplement dry matter (DM) fed and % in diet, total DMI, and total metabolisable energy (ME) fed to dairy cows grazing ryegrass and plantain-based swards in a lower input system (LIRG + PL; 3.5 cow/ha stocking rate and herbage received 150 kg nitrogen/ha/year), perennial ryegrass–white clover mix sward in a lower input system (LIRG; 3.5 cow/ha and herbage received 150 kg nitrogen/ha/year), or perennial ryegrass–white clover mix sward in a higher input system (HIRG; 5 cow/ha and herbage received 300 kg nitrogen/ha/year) during the lactation period (from August to May) in 2017/18 and 2018/19 milking years.

Item	2017/18					2018/19
	LIRG + PL	LIRG	HIRG	LSD	p Value	LIRG + PL	LIRG	HIRG	LSD	p Value
Grazing rotation (d)
Spring	56.4 ± 32.1	56.4 ± 32.1	56.7 ± 31.8			43.7 ± 26.8	42.4 ± 27.0	42.3 ± 26.7
Summer	21.6 ± 0.8	20.0 ± 0.0	22.0 ± 0.0			21.9 ± 2.5	21.9 ± 2.5	20.0 ± 0.0
Autumn	22.9 ± 2.6	22.9 ± 2.6	22.0 ± 0.0			25.4 ± 1.4	25.4 ± 1.4	20.4 ± 1.4
Pre-grazing herbage height (cm)
Spring	6.76	6.84	7.46	0.32	<0.001	8.25	8.54	8.99	0.32	<0.001
Summer	7.64	7.64	7.61	0.45	0.994	7.87	7.83	7.82	0.23	0.867
Autumn	6.70	6.68	6.71	0.28	0.977	6.58	7.04	6.80	0.24	<0.001
Herbage DMI
t/cow	3.30	3.33	2.45	0.137	<0.001	3.27	3.37	2.64	0.151	<0.001
t/ha	11.54	11.65	12.24	0.580	0.019	11.71	11.8	13.21	0.638	<0.001
Supplement fed (DM)
t/cow	1.12	1.07	1.88	0.017	<0.001	0.98	0.75	1.29	0.031	<0.001
t/ha	3.91	3.75	9.40	0.077	<0.001	3.42	2.61	6.50	0.136	<0.001
% in diet	26.2	25.4	45.1	1.13	<0.001	23.1	18.4	33.1	0.95	<0.001
Total DMI 1
t/cow	4.29	4.26	4.22	0.137	0.535	4.26	4.11	3.94	0.158	<0.001
t/ha	15.02	14.89	21.10	0.590	<0.001	14.37	14.90	19.71	0.651	<0.001
Total ME fed (MJ/cow)	49,309	49,400	47,122	1610.2	0.002	49,678	48,402	44,939	1931.0	<0.001

¹ Total DMI = herbage intake + supplement fed, assuming supplement utilisation of 100%.