Document Type

Dissertation - Open Access

Award Date


Degree Name

Doctor of Philosophy (PhD)


Animal Science

First Advisor

Howard H. Voelker


This research was conducted to explore the possibility of utilizing surplus whey in dairy cattle rations. Four experiments determined the influence of whey on preservation, digestibility and feeding value of alfalfa haylage. The last experiment was initiated to evaluate dried whey as a grain supplement. When dried whole whey was added at O, 1, and 10% levels to reconstituted alfalfa haylage (chopped baled hay plus 50% water) and preserved in sealed metal containers, it reduced pH, decreased acetic acid, and increased lactic acid. The general pattern of fermentation was better in whey-treated haylages than in corresponding untreated haylages. An in vivo digestion trial using four Holstein steers, indicated that the whey-treated haylages had higher digestibilities of all chemical constituents analyzed except protein than did the untreated haylages. Correlation analyses suggested that the higher digestibilities were not due to the lower intakes of corresponding chemical constituents. Hay was also compared with reconstituted whey-treated haylage. The haylage was preserved with 1% dried whey. A feeding trial conducted with 20 Holstein cows for 15 weeks in a double reversal design showed similar dry matter consumption from h·7 and haylage. Average daily body weight gains for cows were .40 kg for haylage and .15 kg for hay which 2 were significantly different (P<.01). Milk and fat production as well as persistency of production on hay and haylage were not significantly different. When 24 heifers were fed these forages for 3 months, average daily gains on haylage were 1.00 kg, on hay .81 kg (P<.05), while dry matter intakes from bother forages were similar. In vitro dry matter and cellulose digestibilities of haylage were significantly higher than those of hay. In another experiment, untreated haylages or haylages treated with 2% dried whey were fed ad libitum to 10 Holstein cows each for a 12-week continuous trial. The cows received concentrates at 1 kg/2.55 kg milk yield. Milk production and composition were similar for both treatment groups. Cows fed whey-treated haylage had higher body weight grain (P<.01) than that for the cows fed untreated haylage. Rumen pH and volatile fatty acid (VFA) values revealed no significant differences due to treatment. Results of the digestion trial using four Holstein steers showed higher digestibilities of all chemical constituents except ether extract for whey-treated haylages than for the untreated haylages. A comparison between dried whey and lactose as a haylage additive was also made. First cutting alfalfa at 60% dry matter was chopped, treated with 0 and 2% dried whey and preserved in oxygen-controlled silos. Materials from the same source and the same dry matter treated with 0, 1.4, and 7% lactose were also preserved in sealed metal containers. Treatment levels containing 0 and 1.4% lactose corresponded to the relative amounts of lactose in the dried whey used in this study. Treated haylages had lower pH and higher lactic acid contents than the untreated haylages. Acetic acid concentrations in all haylags were below 1%. Treated haylages had more digestible chemical constituents than the corresponding untreated haylages. Lactose and whey were comparable in improving the digestibilities of haylages. Hay (from the same source) had lower digestibility coefficients than the haylages. Digestibilities of chemical constituents were usually highest for 7% lactose haylage. Total VFA concentrations in rumen fluids of steers were lowest for hay and highest for 7% lactose haylage. Inconsistent treatment effects were noted on percentages of individual rumen VFA and acetate to propionate ratio. Dried whey was evaluated as a grain supplement in a 13-week continuous lactation trial using 20 Holstein cows. The experimental diet contained 5% dried whole whey and had the same amount of crude protein as the control diet. Milk yields, persistency of milk production, milk fat, milk protein, and total solids percentages were not altered by whey supplementation. Dried whey at this level as a grain supplement was not found to be advantageous to cows in late lactation.

Library of Congress Subject Headings

Dairy cattle -- Feeding and feed
Animal nutrition




South Dakota State University

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Dairy Science Commons