Feeding value of bio-fuel co-products for lactating dairy cows
Abstract
Bio-fuel co-products, such as distillers grains and glycerol have become readily available, but present challenges of incorporation into current feeding operations. Rapid spoiling is inherently associated with wet distillers grains with solubles (WDGS). Herd size and storage facilities may limit the use of WDGS by producers, impact storage losses and influence the use of WDGS. Experiments were conducted to evaluate the feeding value of co-ensiled or re-ensiled WDGS as a method to reduce WDGS storage losses. For the corn co- and re-ensiling feeding experiments, WDGS was added to corn fodder and corn silage, respectively, in a 64:36 ratio (DM basis) and ensiled in bag silos. For the haycrop co- and re-ensiling feeding experiments, WDGS was added to direct-cut haycrop or haycrop silage, respectively, in a 37:63 ratio (DM basis) and ensiled in bag silos. Four separate 3-period switchback experiments were used to determine the effects of WDGS handling method on DM intake (DMI) and milk production. Total mixed rations containing 15% WDGS were prepared from co- or re-ensiled WDGS mixtures or from individual feed ingredients mixed at feeding. Milk production, composition, and DMI did not differ (P>0.05) for cows fed co-ensile WDGS diet compared to the corn fodder control diet. Milk production and DMI did not differ (P < 0.05) for cows fed re-ensiled WDGS compared to the corn silage control diet. There was an increase of milk fat percentage for cows fed the re-ensiled WDGS diet. Milk production and DMI were significantly greater (P < 0.05) for cows fed diets containing WDGS that had been coensiled with direct-cut haycrop forage. Milk production and DMI did not differ (P > 0.05) but there was a decrease (P < 0.05) of milk solids when cows were fed diets containing WDGS re-ensiled with haycrop silage. Lab scale silos were also used to determine the effects of combinations of WDGS and either corn or haycrop forage on relative stability of the mixtures. Mixtures containing WDGS had greater (P < 0.05) stability compared with forage alone. These data indicate the feeding value of WDGS is not negatively affected when co- or re-ensiled with fresh forage or stored in a blend with previously preserved silage. This alternative for WDGS storage may provide options to reduce spoilage and increase flexibility of utilizing WDGS for dairy producers. Glycerol can alleviate the symptoms of ketosis when delivered as an oral drench and would eliminate the need for restraining cows to drench, yet deliver a glucogenic substrate, to alleviate the fatty liver-ketosis complex, and improve lactational performance. The objective of this experiment was to study the responses of ruminal, duodenal, and blood metabolites to glycerol under different methods of delivery. Delivery methods for glycerol were assessed using glycerol in treatments: (1) dietary; (2) rumen dose; or (3) oral-drench. Feeding glycerol as a component of the TMR was not as valuable as drenching or dosing glycerol for glycerol to reach the rumen or duodenum.
Degree
M.S.
Advisors
Donkin, Purdue University.
Subject Area
Animal sciences
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