Replacing soybean meal for wet brewer’s grains or urea
on the performance of lactating dairy cows
Abstract The purpose of this research was to evaluate the
partial replacement of soybean meal (SBM) for wet brewer’s
grains (WBG) or urea on the performance of lactating dairy
cows. The second investigated whether WBG ensiled with
corn kept animal performance in low- and high-producing
dairy cows compared withWBG. In experiment I, 40 Holstein
cows were used in 4×4 Latin square design. The treatments
comprised WBG or urea as partial replacement for SBM, as
follows: control (diet based on SBMand 1%of urea), 10%of
WBG, 20 % of WBG, and 2 % of urea. Dry matter intake
(DMI) was not affected by treatments. WBG increased milk
yield linearly, but it decreased with urea. Milk fat content
responded quadratically to WBG levels. Milk protein content
decreased, while plasma urea nitrogen increased with high
urea addition. In experiment II, 42 Holstein cows were divided
into two groups according to production levels. Eighteen cows
composed the group of low producing, while the highproducing
group comprised 24 cows. The experimental design
was a crossover with two periods of 14 days. The experimental
treatments consisted of feedingWBG orWBG ensiled
with ground corn. Regardless of the production level, no difference
in milk yield and milk composition between treatments
was observed.
Introduction
Recently, costs of feeding ingredients are on the rise, and
alternatives to reduce corn and soybean meal (SBM) in diets
have been studied (Wanapat et al. 2012; Carmo et al. 2015).
Brewery byproducts are residues of the beer industry and can
be fed to livestock wet, dried, or ensiled. Their use reduces the
feeding costs and creates an alternative for the use of brewer’s
grains (Aliyu and Bala 2011). Due to high protein content and
favorable balanced, amino acid profile in the ruminally
undegradable protein (Cozzi and Polan 1994) led to the replacement
of wet brewer’s grains (WBG) for SBM in dairy
rations.
Previous researchers indicated that partial or complete replacement
of the protein source in the diet for WBG did not
affect milk yield (Miyazawa et al. 2007). However, this effect
is not consistent in some studies. Another alternative to reduce
SBM inclusion in diets is to increase urea content, especially
because of its low cost. However, performance of dairy cows
varies greatly, which is associated with the amount of urea fed
(Brito and Broderick 2007; Sinclair et al. 2012; Giallingo et al.
2015).
Feed quality and stability during storage are obstacles in
WBG because high moisture content, along with polysaccharide
and protein, makes WBG susceptible to microbial growth
and spoilage in a short period of time (Stojceska et al. 2008).
One alternative to overcome these issues is ensilage. Previous
research showed that WBG combined with dried feedstuffs
increased digestibility and aerobic stability (Wang and
Nishino 2008).
However, information about the effects of WBG or WBG
ensiled on dairy cow performance are scarce in tropical conditions,
whereWBG could deteriorate faster and decrease nutritive
value. The purpose of this study was to evaluate the
partial replacement of SBM for WBG or urea on the