Effects of alfalfa silage storage structure and roasting corn on ruminal digestion and microbial CP synthesis in lactating dairy cows
Articolo
Data di Pubblicazione:
2012
Citazione:
Effects of alfalfa silage storage structure and roasting corn on ruminal digestion and microbial CP synthesis in lactating dairy cows / S.J. Krizsan, G.A. Broderick, C. Promkot, S. Colombini. - In: ANIMAL. - ISSN 1751-7311. - 6:4(2012), pp. 624-632.
Abstract:
The objective of this experiment was to quantify the effects of unroasted or roasted ground-shelled corn (GSC), when fed with
alfalfa ensiled in bag, bunker, or O2
-limiting tower silos on ruminal digestion and microbial CP synthesis in lactating dairy cows.
The roasted corn was heat-treated in a propane-fired roasting system. Alfalfa was harvested as second cutting from fields with
regrowth of the same maturity. A portion of each field was allotted to each silo. The diets with 3 3 2 factorial arrangement of
treatments were fed to six multiparous rumen-cannulated Holstein cows in a cyclic change-over design with five 21-day periods.
Experimental diets were comparable and averaged (on dry matter (DM) basis): 410 g/kg alfalfa silage (AS), 150 g/kg corn silage,
350 g/kg GSC, 50 g/kg soybean meal, 40 g/kg roasted soybeans, 177 g/kg CP, 264 g/kg NDF and 250 g/kg starch. Nutrient flow was
quantified by the omasal sampling technique with use of three markers (Co, Yb and indigestible NDF). Continuous infusion of 10%
atom excess (
15
NH4
)2
SO4 was used to label microbial CP. None of the interactions between storage structure of dietary AS and
corn type were significant. DM intake was not different among dietary treatments, averaging 24.5 kg/day across diets. Means of
ADF digested in the rumen for cows fed diets with AS from bag, bunker and O2
-limiting tower silo were 2.1, 1.7 and 2.1 kg/day,
respectively, and was lower in cows fed AS from the bunker silo. This response may partly be a reflection of the higher intake
of ADF by cows fed AS ensiled in the O2
-limiting tower silo compared with the bunker. There was a slightly greater supply of
fermentable substrates for cows fed diets with roasted compared with unroasted GSC. The small increases in yield of milk protein
and lactose observed in the previous production trial in cows fed diets containing roasted corn may have occurred because of
greater supply of fermentable substrates
Tipologia IRIS:
01 - Articolo su periodico
Keywords:
alfalfa silage; dairy cow; microbial CP synthesis; omasal flow; roasted dry corn
Elenco autori:
S.J. Krizsan, G.A. Broderick, C. Promkot, S. Colombini
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