Diets fed during the experimental and control
phases had similar ingredient compositions with the
primary difference being the form of the supplemental
lipid added to the concentrate (Table 1). The forage
was alfalfa hay fed free choice. In all cases, WPI-based composite gel was the primary form of the lipid supplement
fed with the basal concentrate during the
experimental phase. During the control phase, unprotected
yellow grease (YG) was the lipid supplement
added to the concentrate. The YG diet with unprotected
lipid was used to allow the goats to return to
baseline with respect to FA composition of milk lipids.
In addition, the original intent of the study was to
measure oxidative stability of the milk lipid based on
hexanal and propanal concentrations. However,
methods could not be established in our laboratory.
The WPI gel preparations were added to the basal concentrate
immediately prior to each feeding. Particle
size of the gels was reduced prior to inclusion into the
concentrate using a cheese grater (Bradshaw International,
Rancho Cucamonga, CA, USA). The two lipid
sources were soya bean (S) oil and linseed (L) oil
(Table 2). Composites were formulated to yield a series
of feed supplements that only differed in their FA
composition (Tables 3, 4 and 5). The percentage of
lipid in the supplements was 61.3% WPI/S, 59.5%
WPI/SL and 59.6% WPI/L. The proportion of S and L
included in the gels was adjusted to yield gels with different
n-6 to n-3 ratios. Treatment variables consisted
of WPI gels containing (i) 100% S (WPI/S), (ii) a 1:1
(wt/wt) mixture of S and L (WPI/SL) and (iii) 100% L
(WPI/L).
Diets fed during the experimental and controlphases had similar ingredient compositions with theprimary difference being the form of the supplementallipid added to the concentrate (Table 1). The foragewas alfalfa hay fed free choice. In all cases, WPI-based composite gel was the primary form of the lipid supplementfed with the basal concentrate during theexperimental phase. During the control phase, unprotectedyellow grease (YG) was the lipid supplementadded to the concentrate. The YG diet with unprotectedlipid was used to allow the goats to return tobaseline with respect to FA composition of milk lipids.In addition, the original intent of the study was tomeasure oxidative stability of the milk lipid based onhexanal and propanal concentrations. However,methods could not be established in our laboratory.The WPI gel preparations were added to the basal concentrateimmediately prior to each feeding. Particlesize of the gels was reduced prior to inclusion into theconcentrate using a cheese grater (Bradshaw International,Rancho Cucamonga, CA, USA). The two lipidsources were soya bean (S) oil and linseed (L) oil(Table 2). Composites were formulated to yield a seriesof feed supplements that only differed in their FAcomposition (Tables 3, 4 and 5). The percentage oflipid in the supplements was 61.3% WPI/S, 59.5%WPI/SL and 59.6% WPI/L. The proportion of S and Lincluded in the gels was adjusted to yield gels with differentn-6 to n-3 ratios. Treatment variables consistedof WPI gels containing (i) 100% S (WPI/S), (ii) a 1:1(wt/wt) mixture of S and L (WPI/SL) and (iii) 100% L(WPI/L).
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