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Effect of a homofermentative lactic acid bacteria additive on the quality of sugar-beet pulp silage and animal response of dairy cows with restricted access to pasture

Rubén Pulido1*, Eduardo García1, Ignacio Beltrán2, José Daza3, Juan Keim4, and Ismael Castillo5

Sugar-beet (Beta vulgaris L. subsp. vulgaris) pulp is a valuable by-product from the manufacture of beet sugar fresh which is normally preserved in the form of silage. The aim of the present research was to evaluate the effect of adding a homofermentative lactic acid bacteria silage additive during the ensiling period on fermentation and quality of sugar-beet (SB) pulp silage and the animal performance of dairy cows given restricted daily access to pasture. Twelve Holstein × Friesian crossbred cows were assigned to two groups according to milk yield, body weight, days in milk, parity and body condition score. Groups were randomly allocated to two treatments: silage of SB pulp without additive (control diet, SB) and silage of SB pulp with additive (SB+additive). The experiment was carried out in two periods of 28 d each. Once finished each period, cows were crossed for treatments. Chemical composition of SB silage was modified by the additive: Neutral detergent fiber (41.8% vs. 45.7% DM) and metabolizable energy (2.54 vs. 2.55 Mcal kg-1 DM) were greater and butyrate lower (0.34 vs. 4.10 mmol L-1) for SB+additive compared with SB. However, milk production (24.6 and 25.2 kg d-1) and composition were not affected (P > 0.05) by treatments. Similarly, rumen volatile fatty acids were similar between treatments. In conclusion, the use of homofermentative lactic acid additive on SB silage modified the chemical composition of silage and reduced the pasture intake, however, no changes in milk production and composition were detected.

Key words: Beta vulgaris subsp. vulgaris, milk production, rumen fermentation, silage additive.

1Universidad Austral de Chile, Facultad de Ciencias Veterinarias, Casilla 567, Valdivia, Chile.
*Corresponding author (rpulido@uach.cl).
2Instituto de Investigaciones Agropecuarias, INIA Remehue, Casilla 24-0, Osorno, Chile.
3Instituto de Investigaciones Agropecuarias, INIA Tamel Aike, Casilla 296, Coyhaique, Chile.
4Universidad Austral de Chile, Facultad de Ciencias Agrarias, Casilla 567, Valdivia, Chile.
5Empresas Iansa, km 687 Ruta 5 Sur, Quepe, La Araucanía, Chile.

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