Browsing by Author "Vivek Fellner, Committee Chair"

Now showing 1 - 3 of 3

Effects of Protected Fat When Fed to Dairy Cattle and the Interaction Between Supplemental Fat and Antibiotics in Mixed Cultures.
(2003-09-22) Daves, Meredith Gail; Joe Cassady, Committee Member; Vivek Fellner, Committee Chair; Jerry Spears, Committee Member
Fat is added to diets of lactating dairy cattle as an affordable method of increasing the amount of energy available to the animals. Unsaturated fatty acids are desirable end-products of milk production. However, their presence in the rumen can be toxic to ruminal bacteria, which will then decrease digestion. Unsaturated fatty acids are biohydrogenated into saturated fatty acids by specific bacteria in the rumen, which will decrease positive benefits associated with their consumption. Our first study evaluates the efficiency of calcium salts VALFEED 100M and VALFEED 200 in protecting unsaturated fatty acids from biohydrogenation in the rumen and also observes the effects of these 'protected fats' on lactation performance. Twenty-eight Holstein cows in early lactation were divided equally into four different treatment groups: 1) Control (with no supplemental fat); 2) Prilled fat; 3) Calcium salt of VALFEED 100M; 4) Calcium salt of VALFEED 200. Fat supplements were added to diets in place of corn in the concentrate mix at 3.2% of total dry matter intake. Cows were housed in free stalls equipped with Calan gates. The cows were fed twice daily, at 0800 and 1500 in amounts to allow ad libitum consumption. Weekly feed samples were taken and dried in order to calculate daily dry matter intake. Milk production was measured daily, and milk fat and protein content were analyzed at days 30 and 90. Body weights were taken at the beginning (day 0) and the end (day 90) of the trial. Prilled and VALFEED 100M fat supplements decreased (P <0.05) dry matter intake. Body weights were higher (P <0.05) in cows fed the control diet than those fed the prilled and VALFEED 100M diets. VALFEED 200-treated cows had similar (P >0.10) body weights when compared to all treatment groups. Milk yield was highest in cows fed VALFEED 200 (37.1 kg/d), and cows fed prilled and VALFEED 100M diets had lower (P <0.05) milk yields than those fed the control diet (32.0 kg/d, 32.8 kg/d, and 35.1 kg/d, respectively). Feeding VALFEED 100M significantly decreased (P <0.05) milk fat percentage when compared to the control and prilled diets. VALFEED 200 feeding did not significantly alter milk fat percentage when compared to prilled and control diets. Both VALFEED 100 and VALFEED 200 decreased (P <0.05) milk protein percentage. Feeding VALFEED 100M and VALFEED 200 resulted in an increase (P <0.05) in the cis- and trans- isomers of oleic acid (C 18:1) content of milk when compared to the control and prilled treatments. Both VALFEED 100M and VALFEED 200 also increased (P <0.05) linoleic acid (C 18:2) content in milk fat. The addition of VALFEED 100 to dietary rations depresses milk fat percentage (P <0.05) and increases (P <0.05) the percentage of trans-fatty acids in the milk when compared to the addition of VALFEED 200, suggesting that VALFEED 100 is less inert in the rumen than VALFEED 200. As previously mentioned, fat can be used as a feed additive to provide additional energy for the diet, but it also affects ruminal fermentation by decreasing waste loss and increasing feed efficiency. Ionophores, such as monensin, are drugs that alter ion transport and concentration gradients in specific ruminal bacteria. In doing so, they are capable of altering rumen fermentation and improving feed efficiency. Bacitracin is a non-ionophore antibiotic that affects similar bacteria as monensin but has a different mode of action. It also increases feed efficiency in ways similar to monensin. But, when ionophores are added to diets supplemented with fat, ionophore efficiency decreases. This interaction stimulated interest in conducting our second study. The inclusion of fat and ionophore-antibiotics to experimental diets and the sequence of their addition were investigated. Rumen fluid collected from a dry, fistulated cow was incubated in 8 fermentors for a total of eight days. The first two days of the trial represent a stabilization period. On day three, two fermentors received monensin (50 ppm), two received bacitracin (50 ppm), and the other four received fat (4.4% of DMI). On day 6, one of the fermentors receiving monensin and one receiving bacitracin got fat. The other two continued receiving either only monensin or only bacitracin. Of the remaining four fermentors that were receiving fat, one received monensin, one received bacitracin and the other two continued to only receive fat. Methane and pH were recorded several times daily. Culture samples were taken on days 2, 5, and 8 for analysis of SCFA, LCFA, NH3, and PCR. There were no statistical differences (P >0.10) in acetate and propionate production (mM) among treatments. However, the concentration of butyrate was higher (P <0.01) in cultures treated with monensin when compared with cultures treated with bacitracin. The proportion of C 18:2 in rumen bacteria increased (P <0.05) when monensin was added prior to fat in comparison to when fat was added prior to monensin. Preliminary results indicate that the sequence of fat and antibiotic addition effects the growth of Gram- and Gram+ bacteria. The results from this study show that the sequence in which fat and ionophore-antibiotics are added to mixed rumen cultures can alter the response of bacteria to the additives.
Synchronization of Carbohydrate and Protein Metabolism by Ruminal Microbes in a Continuous Culture
(2002-11-25) Mohney, Kathryn Suzanne; Vivek Fellner, Committee Chair; William Miller, Committee Member; Jack Odle, Committee Co-Chair
A major factor in maximizing microbial protein synthesis is the availability of energy and protein in the diet. Our objective was to determine the effect of fermentable carbohydrate and protein on microbial fermentation. Diets were formulated using three ingredients, soybean meal (SBM), ground corn (GC) and soybean hulls (SBH). Corn and SBH were used in ratios of 60:20, 40:40 or 20:60, respectively to prepare high, medium or low non-fibrous carbohydrate (NFC) diets. Soybean meal was included either unextruded (control) or extruded at low, medium or high temperature. Degradability of the N fractions in the control, low, medium and high soybean meal were 97, 80, 80 and 60%, respectively. Diets were arranged as a 3 x 4 factorial (3 levels of corn/soybean hulls and 4 levels of protein) and analyzed as a completely randomized block design. There were no statistically significant interactions seen between NFC and protein sources. Total volatile fatty acids were affected (P<0.01) by the NFC with 78.5, 63.2 and 71.5 mM with increasing NFC levels. The NFC level affected the acetate and butyrate whereas the protein source had an effect on the propionate. Molar ratios of acetate, propionate and butyrate averaged 60.1, 31.0 and 6.79, respectively. Varying the level of fermentable carbohydrate had a negative linear affect on ruminal pH (P<0.01). Extrusion did not alter pH greatly P>0.67). Higher extrusion temperatures altered ammonia concentrations when compared to control or low extrusion. In the low NFC diets, the medium and high extrusion increased (P<0.10) ammonia concentration (29.8 and 32.6 mg/dl, respectively) when compared with control and the low (18.9 and 23.4 mg/dl, respectively). Methane concentration averaged 308 nmoles/ml and was affected by both the NFC treatment and protein source. The high and medium NFC diets increased (P<0.01) bacterial nitrogen percentage (9.0 and 9.5%, respectively) compared to the low NFC diet (8.7%). Data suggest that the fermentability of the structural carbohydrates in SBH was similar to the high starch corn diets. Furthermore, large differences in protein degradability did not seem to have a major impact on microbial fermentation.
Understanding Rumen Fermentation: I. Effect of high DHA algal oil on microbial biohydrogenation and II. Monitoring microbial shifts in response to antibiotics and oil using T-RFLP analysis.
(2007-11-14) Johnson, Meredith Christina; Vivek Fellner, Committee Chair; Jack Odle, Committee Member; Amy Grunden, Committee Member