Observations on alpine pasture utilisation by Italian Brown dairy cows [Lombardy]
2001
Maggioni, L. | Corti, M. | Aliani, S. (Milan Univ. (Italy). Istituto di Zootecnia Generale)
Aim of this study was to estimate alpine pasture herbage quality and intake. Ten Italian Brown lactating cows were summered on an alpine pasture (2170-2335 m a.s.l.) and supplemented with an high energy concentrate (5.56 kg DM/d) and hay (0.84 kg DM/d). Subjects and other 28 cows of the herd grazed a large pasture (16 ha) during a 8 d trial. The availability and quality of pasture were estimated by the long stripes technique. Herbage nutritional values were studied in samples obtained by simulated grazing technique as well. Herbage intake was estimated both by nutritional balance and the n-alkanes technique [dosed C sub (32) as external marker, natural C sub (31) as internal marker]. Cows selected herbage with high energy value (0.83 milk FU/kg DM). Average milk yield (21.7 +- 3.2 kg/d) was high, whereas butterfat content quite low (3.48 +- 0.35%). Optimal milk urea levels (25.8 +- 2.1 mg/dl) indicated a favourable dietary energy/protein ratio. Herbage intake figures obtained by energy balance and the n-alkanes methods attained 9.5 and 9.3 kg DM/d respectively. It appears that, even under extensive grazing conditions, the high energy value of ingested forage may support high milk yield as long as adequate supplementation is given. The different methods employed for herbage intake estimation provided similar results, but the n-alkanes method seems more suitable to alpine pasture conditions
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