Rick Stock

In vitro starch disappearance procedure modifications

Four in vitro experiments evaluated the effects of ruminal fluid inoculum:artificial saliva ratios, grinder type, grind size, and diet of ruminal fluid donor on in vitro starch disappearance. Experiment 1 examined rates of starch disappearance and coefficients of determination obtained by linear regression of starch disappearance using five grain sorghum (Sorghum bicolor (L.) Moench) lines, a corn (Zea mays L.) control, and a wheat (Triticum aestivum L.) control. Grains were incubated for 4, 8, 12, 16, and 20 h with inoculum varying in proportion of ruminal fluid and artificial saliva (1:1, 1:2, 1:3, and 1:4). In vitro rates of starch disappearance and coefficients of determination were similar for the 1:2, 1:3, and 1:4 inoculum dilutions and were higher (quadratic, P 0.10) by grain type fed; however, absolute rates of digestion varied among inoculate sources. Grinder, grind size, and ruminal fluid inoculum:artificial saliva ratios affected rate of starch disappearance in samples digested in vitro. Diet of ruminal fluid donor affected the rate of starch digestion, but not the relative ranking of the grains. If rates are to be compared across in vitro runs for different grains, these processing and dietary factors must be kept constant.

Relevance of Bypass Protein to Cattle Feeding 13

Summary The primary cost for supplemental protein is for that portion of the protein which escapes (or bypasses) rumen digestion. Therefore, economical use of protein sources requires good estimates of protein bypass. This can be done by intestinal digesta collection or by animal growth, in order to adequately interpret estimates of bypass from growth studies, protein must be shown to be the first limiting nutrient and protein sources must be compared at levels below the animal’s requirement. Growth studies conducted using these criteria give bypass estimates similar to intestinal collection trials. High bypass protein sources can be effectively used in supplement formulations. Through the use of soybean meal equivalent values, supplements equivalent in feeding value to soybean meal can be formulated. Urea is used as an inexpensive source of rumen ammonia thus reducing the cost of the supplement containing bypass protein. Supplements containing bypass protein and urea can be supplied to producers at a lower cost than more traditional “all natural” protein supplements.

Effect of feeding combinations of wet distillers grains and wet corn gluten feed to feedlot cattle.

Three experiments were conducted to evaluate the use of combinations of wet corn gluten feed (WCGF) and wet distillers grain plus solubles (WDGS) in dry-rolled and high-moisture corn-based finishing diets for beef cattle. In Exp. 1, 250 steers (BW = 343 +/- 13.5 kg) were fed 5 treatments consisting of a corn-based, control diet with 0% coproducts, and diets including 30% WCGF, 30% WDGS, 15% WCGF plus 15% WDGS, or 30% WCGF plus 30% WDGS. No associative effects resulted from feeding 15% WCGF plus 15% WDGS; DMI, ADG, and G:F were intermediate between steers fed WCGF or WDGS at 30% of diet DM. Feeding coproducts in combinations at 30 and 60% of diet DM increased ADG, G:F, and final BW (P < 0.05) compared with the corn-based diet. In Exp. 2, 280 yearling steers (BW = 370 +/- 0.45 kg) were used to evaluate feeding 0, 25, 50, or 75% coproducts as a combination of 50% WCGF:50% WDGS (DM basis). Additional diets were fed containing decreased alfalfa hay at 5, 2.5, and 0% (DM basis) as coproduct blend inclusions increased at 25, 50, and 75% (DM basis), respectively. No interactions were observed between alfalfa hay and coproduct blend levels, and no effects on ADG or G:F (P > 0.21) were observed due to alfalfa hay. Intake, ADG, and G:F responded quadratically (P < 0.05) across coproduct levels, with the greatest ADG and G:F at 25 and 50% blend, and similar ADG and G:F for the 0 and 75% blend levels. In Exp. 3, 504 steers (BW = 376 +/- 16 kg) were fed to evaluate 0, 10, 15, 20, 25, and 30% (DM basis) WDGS in diets containing 30% WCGF (DM basis) as well as a control diet with no coproducts. The inclusion of 30% WCGF in the diets increased DMI, ADG, and G:F (P < 0.05) when compared with control. Response to inclusion level of WDGS tended to be quadratic for DMI (P = 0.12), quadratic for ADG (P = 0.05), and no effect for G:F (P = 0.96). Greatest ADG was achieved with 15 to 20% WDGS inclusion in diets containing 30% WCGF. The use of combinations of WCGF and WDGS in finishing diets resulted in similar or improved steer performance compared with corn, suggesting replacement of corn with coproduct combinations up to 75% diet DM is possible if a roughage source is fed.

Effect of protozoa and urea level on in vitro starch disappearance and amylolytic activity of ruminal microorganisms

Abstract In vitro experiments were conducted to study the effects of protozoa on starch fermentation and amylolytic activity of ruminal bacteria and protozoa. The first experiment consisted of a randomised complete block design with a 3 × 2 × 5 factorial arrangement of treatments. Treatments were grain source (corn, high moisture corn or grain sorghum), inoculum source (a mixed ruminal population or one free of protozoa) and urea addition (0, 5, 10, 20 or 30 mg g −1 of grain). An interaction ( P P P P P P P > 0.01) in amylase specific activity (units ml −1 of protein) was observed for protozoa (0.0802), bacteria (0.0472), and a mixed population (0.0435). The contribution of protozoa on the in vitro starch digestion may be dependent on the ammonia N concentrations.

Effects of Corn Processing Method and Protein Concentration in Finishing Diets Containing Wet Corn Gluten Feed on Cattle Performance1

Abstract Three hundred twenty crossbred steer calves (308 kg) were used to determine the effects of corn processing and addition of urea on performance with diets containing wet corn gluten feed (WCGF). The treatment design was a 5 x 2 factorial with factors of corn processing (dry-rolled, DRC; fine-ground, FGC; rolled high-moisture, RHMC; ground high-moisture, GHMC; or steam-flaked corn, SFC) and CP concentration (14 or 15%) with 4 pens per treatment and 8 steers per pen. The final diet contained 60% corn, 25% WCGF, 10% corn silage, and 5% supplement (DM basis). No significant protein x grain processing interactions occurred for feedlot performance or carcass variables. Steers fed DRC and FGC had similar DMI, but greater (P

Ruminal fermentation and in situ starch digestion with high moisture corn, dry rolled grain sorghum or a mixture of these grains

An experiment was conducted to study the effects of feeding mixtures of high moisture corn (HMC) and dry-rolled grain sorghum (DRGS) on ruminal fermentation and site and the extent of starch digestion. Three ruminally fistulated steers were used in a replicated Latin square design. Dietary grain treatments were:(1) 100% HMC;(2) 67% HMC:33% DRGS; and (3) 100% DRGS. Starch and DM intake (P<0.01), and in situ rate of starch disappearance of DRGS (P<0.05) increased linearly as sorghum was added to the diet. Entodinium counts and total amylolytic activity tended to be higher (quadratic, P=0.20) in the mixture. VFA and molar proportion were not affected by the treatments. No associative effects were detected in ruminal starch digestion. Ruminal protozoa numbers were increased when DRGS and HMC were combined.

Urea vs. urea and escape protein for finishing calves and yearlings

Three finishing trials, two with calves and one with yearlings, were conducted to evaluate supplementing dry rolled corn-based diets with either urea or a combination of urea and escape protein. In Trial 1, 160 crossbred steer calves (285 ± 5 kg body weight (BW)) were fed (187 days) finishing diets supplemented with urea, soya-bean meal (SBM), urea and feather meal (FTH), or a combination of urea, 23 FTH and 13 blood meal (BM); (crude protein basis). The FTH and FTH/BM treatments were fed at 50% of the supplemental N with urea supplying the remaining N. Calves supplemented with SBM gained faster and more efficiently (P 0.10) by treatment. In Trial 2, 42 crossbred steer calves (255 ± 3 kg BW) were fed (175 days) finishing diets supplemented with SBM or urea and BM (urea and BM supplied equal amounts of supplemental N). Gain and efficiency were not affected (P > 0.10) by treatment. In Trial 3, 400 yearling steers and heifers (342 ± 5 kg BW) were fed (117 days) diets supplemented with the following sources and percentages of supplemental N: urea 100%; urea 50%, SBM 50%; urea 75%, FTH 25%; urea 50%, FTH 50%; urea 50%, FTH 25%, meat and bone meal 25%. During the first 31 days, cattle gained faster (P 0.10) by source of supplemental protein. These data indicate that young (7–10 months of age), large-framed calves may gain faster and more efficiently during the early finishing period when supplemented with a combination of escape protein and urea compared with urea alone, but not later in the finishing period. Urea supplementation alone is adequate for rapidly gaining yearling cattle.

Evaluation of alfalfa type as a roughage source in feedlot adaptation and finishing diets containing different corn types

In high grain diets, effects of roughage type or source may depend on diet (adaptation vs. finishing) and grain type fed. In four feedlot trials, alfalfa hay (AH) and alfalfa silage (AS) were compared as roughage types during grain adaptation and finishing phases of production. Roughage types were compared in dry whole corn (DWC), dry rolled corn (DRC), whole high moisture corn (WHMC), and ground high moisture corn (GHMC) diets. Common diets were fed during periods in which direct comparisons of alfalfa or corn types were not made. In adaptation trials, a roughage by corn type interaction (P < 0.10) was observed for intake when dry corn was fed; steers fed AS with DWC ate more (10.0 kg) than steers fed AS with DRC (9.5 kg), while steers fed AH had similar intakes when fed with DRC (9.7 kg) or DWC (9.6 kg). When high moisture corn diets were fed, greater intakes (P < 0.05) and gains (P < 0.10) were observed for steers fed AS than for steers fed AH. Effects of roughage fed in the adaptation period were not carried over into the finishing period, in which high energy diets were fed. In finishing phase trials, effects of roughage type were not observed in steer performance or carcass traits. The data suggest that differences in effects of roughage types are observed only in adaptation diets. Observed performance differences are primarily attributed to differences in quality and/or fiber content between AH and AS.

Using Sweet Bran instead of forage during grain adaptation in finishing feedlot cattle.

Two trials evaluated adapting cattle to a finishing diet using wet corn gluten feed compared with traditional methods using forage. A 33-d grain adaptation metabolism trial (Exp. 1) compared decreasing wet corn gluten feed (Sweet Bran; Corn Milling unit, Cargill Corn Milling, Blair, NE) while increasing corn inclusion (SB) and a traditional grain adaptation system decreasing alfalfa hay while increasing corn with no Sweet Bran inclusion (CON). Ruminal pH, intake characteristics, and 24-h in situ digestibility were evaluated using 8 ruminally fistulated steers (291 kg BW [SD 19]). Steers (4/treatment) were adapted to finishing diets across 4 periods consisting of 5, 7, 7, and 7 d and then fed a finishing diet for 7 d. No period × adaptation diet interactions were observed ( ≥ 0.12). Average ruminal pH decreased ( < 0.01) whereas time and area below a pH of 5.6 increased ( ≤ 0.02) for the SB adaptation system compared with the CON adaptation system. Cattle adapted using SB had greater DMI than cattle adapted using CON ( < 0.01). As steers were adapted to finishing diets, DMI increased ( = 0.01), average ruminal pH decreased ( = 0.05), and time and area below a pH of 5.6 increased ( ≤ 0.04) for both treatments. Ruminal pH for CON steers decreased from 6.59 to 6.12 across periods as corn replaced alfalfa hay whereas ruminal pH decreased from 6.00 to 5.79 for SB steers. Steers adapted using SB had greater ( ≤ 0.05) in situ digestion of adaptation diets than steers adapted using CON for adaptation periods 3, 4, and 5. The SB diets were more digestible than the CON diets when incubated in either CON- or SB-fed steers for adaptation periods 1 and 2 ( < 0.01). Experiment 2 used 240 finishing steers (273 kg BW [SD 14]) to determine performance impacts of using Sweet Bran instead of forage to adapt cattle to finishing diets. Steers were fed either decreasing Sweet Bran inclusion while increasing corn (SB) or decreasing alfalfa hay inclusion while increasing corn (CON). Treatments were applied only during grain adaptation (26 d) and all steers were finished on a common diet containing 35% Sweet Bran for an additional 147 d. Steers adapted using SB had greater ( ≤ 0.01) final BW, ADG, G:F, and HCW compared with steers adapted using CON, even though treatments differed only the first 26 d. Grain adaptation treatment had no effect ( ≥ 0.13) on carcass quality. These results indicate that Sweet Bran can be used to adapt cattle to finishing diets instead of forage and improves ADG and G:F while decreasing the forage needs of feedlots.

Effects of fat supplementation to diets high in nonforage fiber on production responses of midlactation dairy cows

The effects of dietary nonforage fiber sources on production responses of lactating dairy cattle have been well described, but interactions with other components of the diet have been less thoroughly explored. We investigated the effects of adding 2 commonly fed fat sources to a ration featuring high levels of nonforage fiber supplied by a corn milling by-product. Midlactation Holstein cows were blocked by parity, stratified by days in milk, and randomly assigned to 1 of 6 pens (12 cows/pen). Pens were randomly assigned to treatment sequences in a 3 × 3 Latin square design, where the treatments consisted of prilled saturated fat (SAT; Energy Booster 100, Milk Specialties Co., Dundee, IL), calcium salts of long-chain fatty acids (UNS; Megalac, Church and Dwight Co. Inc., Princeton, NJ), or no added dietary fat (control), with fat sources included to provide 1.2% added fat (dry matter basis). Treatment periods were 21 d; milk and feed samples were collected and milk yield and feed intake were recorded for the last 4 d of each period. Results were analyzed with mixed models with pen as the experimental unit, and orthogonal contrasts were employed to evaluate the overall effect of added fat and the effect of fat source. Dry matter intake and milk yield tended to increase with added fat. Protein content decreased with fat supplementation, to a greater degree for UNS than for SAT, but protein yield was not affected. Fat content, fat yield, and energy-corrected milk yield were not affected by treatment. Conversion of feed to milk tended to increase for UNS compared with SAT. Fat supplementation to diets high in nonforage fiber had effects that were similar to those reported for more traditional lactation diets, except for the dry matter intake response.