Three studies were conducted to evaluate titanium dioxide (TiO2) as a digestibility marker for cattle. In Exp. 1, eight steers consumed prairie hay ad libitum with or without dietary supplements. Fecal recovery of TiO2 averaged 93% and was not affected (P = 0.47) by supplement. Digestibilities calculated with reference to TiO2 were not different (P = 0.15) from those based on total fecal collections. In Exp. 2, two steers were limit-fed corn-based diets. Fecal recovery of TiO2 averaged 95% and that of chromic oxide (Cr2O3) averaged 113%. Digestibilities calculated with reference to TiO2 were underestimated (P < 0.01) by 1.1 percentage units relative to those based on total fecal collections, and those calculated with reference to Cr2O3 were overestimated (P < 0.01) by 2.0 percentage units. In Exp. 3, eight steers in a replicated 4 x 4 Latin square consumed corn-based diets ad libitum. Fecal recovery of TiO2 averaged 90%, whereas that of Cr2O3 averaged 98%. Digestibilities calculated with reference to TiO2 were underestimated (P < 0.01) by 1.6 to 4.3 percentage units, whereas those calculated with reference to Cr2O3 were not different (P = 0.31) from those based on total fecal collections. Future research is warranted to determine the usefulness of TiO2 in measuring digestibility in cattle.

Six ruminally cannulated steers (345 +/- 20 kg initial BW) were used in a 6 x 6 Latin square to evaluate effects of diet and antibiotics on ruminal protein metabolism. Two diets and three antibiotic treatments were arranged factorially. One diet contained (DM basis) 72% dry-rolled corn, 12% soybean meal, 10% alfalfa hay, and 4% molasses (SBM), and the other contained 63% dry-rolled corn, 30% wet corn gluten feed, and 5% alfalfa hay (WCGF). Antibiotic treatments included control, virginiamycin (175 mg/d; VM), and monensin/tylosin (250 and 100 mg/d, respectively; MT). Steers were fed at 12-h intervals at a rate of 2.4% of empty BW daily. Each period included 18 d of adaptation and 3 d of ruminal fluid collections. Samples were collected at 0, 2, 4, 6, 8, and 10 h after the morning feeding on d 19 and 20. On d 21, rumens were dosed 2 h after the morning feeding with 350 g of solubilized casein to evaluate in vivo ruminal protease and deaminase activities. Ruminal fluid samples were collected 1, 2, 3, 4, and 6 h after the casein dose. On d 19 and 20, antibiotics had no effect on ruminal pH or concentrations of VFA, lactate, ammonia, ciliated protozoa, alpha-amino nitrogen (AAN), or peptide N, but VM reduced (P < 0.01) the concentration of isovalerate compared to MT and control. After casein dosing (d 21), peptide N concentration was unaffected by antibiotics, but AAN were higher (P < 0.01) for VM than MT and control. Relative to MT and control, VM reduced ruminal isovalerate (P = 0.05) and increased ruminal propionate (P < 0.01) on d 21. Ruminal pH was lower (P < 0.01) in steers fed SBM than in steers fed WCGF, but lactate concentrations were unaffected by diet. Steers fed SBM had higher (P < 0.05) ruminal concentrations of total VFA and propionate. Ammonia concentrations were lower before feeding and higher after feeding for steers fed WCGF (P < 0.01). Steers fed WCGF had higher counts of total ciliated protozoa than steers fed SBM (P < 0.05) due to greater Entodinium sp. (P < 0.05). Steers fed WCGF had higher (P < 0.01) ruminal AAN and peptide N concentrations than those fed SBM on d 19 and 20. After casein dosing, ruminal peptide N concentrations were similar, but AAN were lower (P < 0.01) for WCGF than SBM. Overall, VM appeared to depress ruminal deaminase activity, and MT had minimal effects on ruminal fermentation products. The protein in WCGF appeared to be more readily degradable than that in SBM.

Brand names appearing in this publication are for product identification purposes only. K-State Research and Extension is an equal opportunity provider and employer. Recommended Citation Löest, C.A.; Bindel, D.J.; Titgemeyer, Evan C.; Drouillard, James S.; and Blasi, Dale A. (1998) "Soybean hulls in roughage-free diets for limit-fed growing cattle," Kansas Agricultural Experiment Station Research Reports: Vol. 0: Iss. 1. https://doi. Abstract Three hundred heifers (573 lb initial body weight) were used in a growing study to compare growth performance of cattle fed roughage-free diets comprised mainly of soybean hulls with that of cattle receiving roughage-and corn-based diets and to determine if cattle fed soybean hull-based diets would respond to supplemental methionine hydroxy analogue (MHA; a source of methionine), ruminally protected betaine, or concentrated separator by-product (CSB; a source of betaine). Treatments included 1) a roughage-based diet fed at 2.75% of body weight (ROUGH), 2) a corn-based diet fed at 1.5% of body weight (CORN1.5), 3) a corn-based diet fed at 2.25% of body weight (CORN2.25), 4) a soybean hull-based diet fed at 1.5% of body weight (SH1.5), 5) a soybean hull-based diet fed at 2.25% of body weight (SH2.25), 6) SH1.5 top-dressed with 11.4 g/head daily MHA, 7) SH2.25 top-dressed with 11.4 g/head daily MHA, 8) SH2.25 top-dressed with 7 g/head daily rumenprotected betaine, and 9) SH2.25 top-dressed with 250 g/head daily CSB. Supplemental MHA, betaine, and CSB did not change feed intakes, gains, or feed efficiencies for cattle fed soybean hulls. Heifers fed soyhulls at 2.25% of body weight gained 27% slower (P<.01) than heifers fed the corn-based diet at similar intakes and were 25% less efficient (P<.01). Similar results were observed for cattle fed soybean hulls and corn at 1.5% of body weight. Cattle fed soybean hulls at 2.25% of body weight had gains similar to those of cattle receiving the roughage-based diet at 2.75% of body weight, but feed efficiencies tended to be better (P=0.11) for the cattle receiving soybean hulls because less feed was consumed. The roughage-fed cattle gained 23% less (P<.01) than cattle fed corn at 2.25% of body weight and were 34% less efficient.

Crossbred heifers (756 lb) were used to evaluate the effects of feed-grade betaine on animal performance and carcass characteristics. Heifers had ad libitum access to a finishing diet without betaine or with 4, 8, or 12 g/ day of feed-grade betaine top-dressed at feeding. Feed intakes, gains, and feed efficiencies were not significantly altered by feed-grade betaine. Hot carcass weights tended to increase with the betaine supplementation, but dressing percent; percentage of kidney, pelvic and heart fat; fat thickness; or ribeye area were not altered. Yield grades were numerically greater, and marbling scores significantly greater for heifers supplemented with 4 or 12 g/day of betaine. These results demonstrate that supplementation of feed-grade betaine may have minor effects on performance and carcass characteristics. Summary Crossbred heifers (756 lb) were used to evaluate the effects of feed-grade betaine on animal performance and carcass characteristics. Heifers had ad libitum access to a finishing diet without betaine or with 4, 8, or 12 g/day of feed-grade betaine top-dressed at feeding. Feed intakes, gains, and feed efficiencies were not significantly altered by feed-grade betaine. Hot carcass weights tended to increase with the betaine supplementation, but dressing percent; percentage of kidney, pelvic and heart fat; fat thickness; or ribeye area were not altered. Yield grades were numerically greater, and marbling scores significantly greater for heifers supplemented with 4 or 12 g/day of betaine. These results demonstrate that supplementation of feed-grade betaine may have minor effects on performance and carcass characteristics. (

A 120-d finishing study utilizing 318 heifers (342 kg initial BW) was conducted to examine effects of ruminally protected choline (RPC) in diets containing graded concentrations of tallow. Heifers were blocked according to previous nutrition (full-fed or limit-fed) and allotted to 24 pens containing 11 to 15 heifers. Two pens, one within each block, were assigned to each of 12 factorially arranged treatments including dietary tallow (0, 2, or 4%) and supplemental RPC (0, 20, 40, or 60 g of product daily, estimated to supply 0, 5, 10, or 15 g/d choline postruminally). Heifers were implanted with Revalor-H and fed a finishing diet based on steam-flaked and dry-rolled corn (12.5% CP, 8% alfalfa on DM basis). Dry matter intake decreased (P < 0.10) by 5.4% when tallow was increased from 0 to 4% but was not affected by RPC. Heifers receiving 4% tallow had 7.3% lower gains than those receiving none (P < 0.10). Supplementation of RPC increased (P < 0.10) ADG, with 20 g/d resulting in an 8.6% increase. Similarly, gain efficiency improved (P < 0.10) by 7.6% with addition of 20 g/d RPC. Yield grade and kidney, pelvic, and heart fat both increased linearly (P < 0.10) with fat supplementation. The percentage of carcasses grading USDA Choice was not affected by intermediate levels of RPC but decreased with the highest level (60 g/d). Dressing percentage, hot carcass weight, marbling, and 12th-rib fat thickness were not affected significantly by either tallow or RPC. On d 90, jugular blood was collected from all heifers at 2 h postfeeding. Plasma urea and serum insulin concentrations were not affected by either tallow or RPC. Dietary tallow linearly increased (P < 0.10) NEFA, cholesterol, triglyceride, and total amino acid concentrations. Choline supplementation led to quadratic responses for total amino acids (P < 0.10), with concentrations being greatest for intermediate levels of RPC. Moderate levels of supplemental RPC improved growth performance of finishing cattle without negatively affecting carcass characteristics. Optimum performance was achieved with 20 g of product daily.