T.B. Farran

Evaluation of Revalor-IH and Revalor-IS as Initial Implants Compared with Traditional Initial Implants for Finishing Heifers and Steers

Two commercial feedlot experiments were conducted to compare performance and carcass characteristics of feedlot heifers and steers using 2 implant strategies. In Exp. 1, heifers (n = 1,124;

Alfalfa hay and wet corn gluten feed levelsin steam-flaked corn finishing diets

A 153-day finishing experiment was conducted using 631 heifers to determine optimum alfalfa hay and wet corn gluten feed (WCGF) combinations in steam-flaked, corn-based diets. Diets contained either 2 or 6% alfalfa hay and 25, 35, or 45% WCGF (dry basis). Performance was similar (P>0.16) for cattle fed 2 or 6% alfalfa hay. Gain efficiencies (P<0.05) and fat thickness (P<0.10) declined linearly with increasing amounts of WCGF. For heifers fed 2% alfalfa hay, ribeye area increased with increasing dietary WCGF. However for heifers fed 6% alfalfa hay, ribeye area decreased with increasing dietary WCGF. Liver abscesses were lowest for heifers fed 35% WCGF. Alfalfa hay fed at 2% of diet dry matter is sufficient for steam-flaked corn diets containing 25, 35 or 45% WCGF.

Using a mixture of cottonseed hulls andcottonseed meal to replace alfalfa hay indiets for stressed feeder calves

One 28-day receiving experiment was conducted using 625 exotic x British cross heifers to evaluate growth performance and morbidity on receiving diets that contained either alfalfa hay or a pellet composed of 65% cottonseed hulls and 35% cottonseed meal as the roughage source. Heifers fed the cotton byproduct pellet consumed more feed (P<0.01) but tended to be less efficient than those fed alfalfa hay. Daily gain was comparable between diets (P>0.05), and the percentages of heifers diagnosed, treated, or retreated for respiratory disease were similar.

Refractive index: a rapid method for determination of starch availability in grains

Steam-flaked corn samples were used in a series of experiments to determine if refractive index could be used as a rapid, inexpensive method to predict starch availability. Results were best when samples were incubated for 15 min with 500 to 600 active units of enzyme/gm of grain prior to measuring on a hand-held refractometer. Correlations to starch availability determined from gas production by a commercial lab were R=.64 for whole flakes and R=.79 when samples were ground. Samples of corn flaked to different densities produced estimates of solubility similar to an in situ dry matter disappearance assay (R = .84, P < .01). Furthermore, refractive index yielded estimates of starch solubility that were well related to a commercial lab’s measures of glucose release for samples of flaked corn that were stored for 0 to 48 hours subsequent to flaking.

Combinations of wet corn gluten feed and steam flaked corn in finishing cattle diets

A 152-day experiment was conducted using 615 crossbred steers to evaluate cattle performance when steam-flaked corn in finishing diets was replaced partially with wet corn gluten feed (CGF). Finishing diets contained no wet CGF (0CGF) or 30 and 60% CGF on a dry matter basis (30CGF and 60CGF). Ruminal and fecal pH increased linearly (P<.01) as the proportion of wet corn gluten feed increased. Cattle fed 60CGF gained less than those fed 30CGF (P<.01) and were less efficient than cattle fed 0CGF or 30CGF (P<.05). Dressing percentage was lower (P<.03) for cattle fed 60CGF compared to cattle fed 30CGF. Incidence of liver abscesses increased linearly (P<.01) as the level of CGF increased. Replacing steamflaked corn with wet CGF at 30% of the diet did not alter performance.

Immune response in feeder cattle fed different sources of dietary lipid

Two studies were conducted utilizing crossbred beef steers to evaluate immune response following endotoxin challenge. In Trial 1 steers (n = 20; 688 lb BW) were fed diets containing rolled full-fat soybeans (SOY) or tallow (TALLOW). In Trial 2, steers (n=18; 780 lb BW) were fed diets containing TALLOW, flaxseed (FLAX), or a micro-algae (ALGAE) top-dressed to the TALLOW diet. Both FLAX and ALGAE were sources of omega-3 polyunsaturated fatty acids. In both trials, diets were fed for a 14-day acclimation period prior to intravenous injection of a bacterial lipopolysaccharide(LPS) endotoxin. Injection of LPS in Trial 1 resulted in higher rectal temperatures for animals fed TALLOW compared to those fed SOY. In contrast, plasma concentrations of tumor necrosis factor-α (TNF) were higher for animals fed SOY. Haptoglobin and fibrinogen increased and total white blood cell count decreased in response to LPS, but these measures were not different (P>0.1) between SOY and TALLOW. In Trial 2, rectal temperature was higher for TALLOW (P<0.05) than for FLAX at 3, 4, 5, and 6 hours after the initial injection of LPS. In addition, rectal temperature for TALLOW was higher (P=0.05) at hour 4 when compared to ALGAE and tended (P=0.1) to be higher at hour 5. Serum haptoglobin concentration at 24 hours was higher (P<0.05) for animals fed ALGAE than those fed FLAX or TALLOW. Haptoglobin and fibrinogen concentrations increased at 24 hours after injection with LPS, but were not different at other times among treatments in either trial. Results show that source and type of dietary fatty acid may impact immune response in cattle.

Evaluation of performance in receiving heifers fed different sources of dietary lipid

Two 35-day receiving experiments were conducted using 668 highly stressed crossbred beef heifers to evaluate differences in growth performance, morbidity, and mortality when fed diets containing differing sources of dietary lipid. Heifers received diets containing beef tallow, tallow enriched with a microalgae product containing a high proportion of docosahexaenoic acid (an omega-3 fatty acid), full-fat soybeans, or ground flaxseed. All diets contained approximately 60% concentrate and 40% roughage (alfalfa hay). Feed intake, daily gain, and feed efficiency were poorer (P<0.05) for cattle fed full-fat soybeans than for those fed the other treatments. Feed intake tended to be reduced when micro-algae was top-dressed to the diet, but gain was not negatively impacted. In Trial 2, feed efficiency was improved by the micro-algae. No notable differences among treatments were evident in the percentage of cattle treated for bovine respiratory disease, but cattle fed flaxseed tended to respond better to therapeutic treatments, requiring fewer retreatments.

Effects of grain processing and lipid addition to finishing diets on cattle performance and blood constituents

Experiments were conducted to evaluate effects of grain processing and lipid source on finishing cattle performance, carcass characteristics, and plasma concentrations of glucose, urea, and α-amino nitrogen (amino acids). Eighty yearling Hereford x Angus steers (847 lb) were fed diets containing either steamflaked corn or dry-rolled corn, both fed with and without 4% added tallow. In a fifth diet, ground flaxseed (equivalent to 4% lipids) replaced a portion of steamflaked corn. Diets were fed once daily for 85 days. As expected, cattle fed steamflaked corn were more efficient than steers fed dry-rolled corn. Adding tallow had little effect on performance. Including flaxseed resulted in performance similar to that with tallow addition. Plasma glucose concentrations measured 2 hours after feeding were higher for steers fed steamflaked corn than for steers fed dry-rolled corn, and were higher for cattle fed tallow than for those fed no supplemental fat. Steers fed the flax/steam-flaked corn combination had lower plasma glucose concentrations 2 hours after feeding than those fed steam flaked corn with added tallow (P<0.05). Steam flaking corn increased performance and elevated glucose concentrations compared to dry rolling, suggesting that increasing the ruminal degradable starch allowed for a greater supply of substrates for gluconeogenesis. Adding flaxseed resulted in lower levels of plasma glucose after feeding, compared to tallow. (

Addition of urea to finishing cattle dietscontaining steam-flaked corn andwet corn gluten feed

Three hundred thirty-nine crossbred beef heifers were used in a 74-day finishing study to evaluate effects of adding 0.5% urea to finishing diets containing steam-flaked corn and 34% (dry basis) Sweet Bran wet corn gluten feed (WCGF). Diets were fed once daily ad libitum. Urea addition tended (P<0.06) to increase finishing average daily gain, to improve (P<0.12) feed efficiency, and to increase (P<0.06) fat thickness. Heifers fed urea had a lower percentage (P<0.03) of carcasses grading USDA Choice. This study suggests that finishing diets containing a combination of steam-flaked corn and WCGF may benefit from addition of urea as a source of supplemental ruminally available nitrogen.

Increasing levels of Rumensin® in limit-fed,high energy, growing diets for beef steers and effects on subsequent finishing performance

One hundred sixty-four crossbred beef steers were used to determine optimal Rumensin concentrations in limit-fed, high-energy, growing diets. Diets contained 30, 40, or 50 grams of Rumensin per ton of dry matter (R30, R40, and R50). Average daily gain and feed efficiency during the growing phase were not different (P>.80) among treatments. Steers that received R50 in the growing phase had the highest average daily gains during the finishing phase (P .40).