Supplemental Zinc Sulfate Affects Growth Performance of Finishing Heifers

Zinc is an essential mineral required for normal function of more than 300 enzymes in microorganisms, plants, and animals. Zinc-requiring enzymes participate in metabolism of nucleic acids, proteins, and carbohydrates, all of which are essential for growth of cattle. In addition, zinc is necessary for normal development and function of the immune system. The requirement for zinc in finishing cattle diets has been established at 30 ppm (NRC, Nutrient Requirements of Beef Cattle, 2000), though concentrations recommended by consulting nutritionists and feed manufacturers span a far broader range. The purpose of this study was to evaluate the effects of feeding different levels of zinc on feedlot performance and carcass traits of finishing heifers

Antioxidant Feeding Does Not Impact Incidence or Severity of Liver Abscesses

Liver abscesses are a large source of economic loss in feedlot cattle. Not only do liver abscesses lead to a decrease in feedlot performance, but these livers are condemned in the abattoir and can also lead to a further decrease in carcass value due to trim loss. Tylosin phosphate is a metaphylactic macrolide drug that effectively decreases the occurrence of liver abscesses. The drug is approved by the Food and Drug Administration for over-the-counter use. However, in January 2017 the FDA will require a veterinary feed directive for medically important antibiotics (antibiotics that are used in human health) used in production animal feed. Macrolides are one class of antibiotic that will require a veterinary feed directive. A drug that is accompanied by a veterinary feed directive will require it to be used within the regulations that the FDA has set for the specific drug. This new directive is to encourage the animal production industry to use less medically important antibiotics. It is therefore important to look at alternatives to control liver abscesses in feedlot cattle. Various studies have shown that α-tocopherol acetate increases the humoral response and that ascorbate increases mononuclear lymphocyte counts. These antioxidants are also known to maintain the integrity and structure of ruminal papillae, thereby inhibiting pathogenic bacteria that lead to the formation of liver abscesses from gaining access to the portal blood and then eventually the liver. The objective of this study was to evaluate the impact of antioxidants on feedlot performance, carcass characteristics, and incidence and severity of liver abscesses in finishing heifers

Ruminally-Protected Lysine (SafeGain) Improves Performance of Growing Beef Cattle

Lysine frequently is cited as the first-limiting amino acid for cattle diets. Synthetic lysine, while routinely added to pig diets, is ineffective in fulfilling lysine requirements of cattle due to extensive degradation by microbes within the rumen. Lysine can be encapsulated with compounds, such as saturated fats, that minimize degradation by ruminal microbes, thereby assuring that a greater proportion of the amino acid is available for absorption post-ruminally. The purpose of this experiment was to measure the impact of SafeGain (H.J. Baker & Bro. Inc., Little Rock, AR), an encapsulated form of lysine sulfate, on rate of gain and feed efficiency in backgrounding cattle

Supplemental Zinc Sulfate Interacts with Optaflexx in Feedlot Heifers

Optaflexx is a beta-adrenergic agonist, and is fed to cattle during the final 28 to 42 days on feed to improve growth rate and feed efficiency. Beta-adrenergic agonists are repartitioning agents that stimulate muscle deposition at the expense of fat deposition. Zinc is a trace mineral element that functions as an important component of many enzyme systems, including those associated with nucleic acid synthesis and metabolism of proteins and carbohydrates, thus making it an essential nutrient for growth. The purpose of this study was to evaluate growth, carcass characteristics, and plasma urea nitrogen concentrations in finishing heifers supplemented with Optaflexx at 0 or 200 mg/animal daily, in the presence of 30 or 100 ppm supplemental zinc. We hypothesized that feeding Optaflexx could increase requirements for dietary zinc, and that additional zinc supplementation could increase the growth response to Optaflexx

Effects of flaxseed encapsulation on biohydrogenation of polyunsaturated fatty acids by ruminal microorganisms: feedlot performance, carcass quality, and tissue fatty acid composition

Citation: Alvarado-Gilis, C. A., Aperce, C. C., Miller, K. A., Van Bibber-Krueger, C. L., Klamfoth, D., & Drouillard, J. S. (2015). Effects of flaxseed encapsulation on biohydrogenation of polyunsaturated fatty acids by ruminal microorganisms: feedlot performance, carcass quality, and tissue fatty acid composition. Journal of Animal Science, 93(9), 4368-4376. doi:10.2527/jas2015-9171The objective of this study was to evaluate the efficacy of protecting PUFA within ground flaxseed against ruminal biohydrogenation by encapsulating them in a matrix consisting of a 1:1 blend of ground flaxseed and dolomitic lime hydrate (L-Flaxseed). Crossbreed heifers (n = 462, 346 +/- 19 kg) were blocked by weight and randomly assigned to pens. Pens were assigned to 1 of 6 dietary treatments in a randomized complete block design. Treatment 1 consisted of a combination of 54.6% steam-flaked corn (SFC), 30.0% wet corn gluten feed, 8.0% roughage, and supplement (0% flaxseed). In treatments 2 and 3, a proportion of SFC was replaced with 3 and 6% flaxseed, respectively; in treatments 4, 5, and 6, SFC was replaced with 2, 4, or 6% L-Flaxseed, respectively. Cattle were fed for 140 or 168 d and then harvested in a commercial abattoir where carcass data were collected. Approximately 24 h after harvest, carcasses were evaluated for 12th-rib fat thickness, KPH, LM area, marbling score, and USDA yield and quality grades. Samples of LM were also obtained for determination of long-chain fatty acid profiles. Cattle that were fed diets with 4 and 6% L-Flaxseed consumed less feed than other treatments (P 0.05). Supplementation with flaxseed increased (P 99%; increases for Flaxseed and L-Flaxseed of 0.095 and 0.140 mg of ALA/g of tissue for each percentage of flaxseed added). This study indicates that a matrix consisting of dolomitic lime hydrate is an effective barrier to ruminal biohydrogenation of PUFA; however, adverse effects on DMI limit the amounts that can be fed

Effects of crystalline menthol on blood metabolites in Holstein steers and in vitro volatile fatty acid and gas production

Citation: Van Bibber-Krueger, C. L., Miller, K. A., Aperce, C. C., Alvarado-Gilis, C. A., Higgins, J. J., & Drouillard, J. S. (2016). Effects of crystalline menthol on blood metabolites in Holstein steers and in vitro volatile fatty acid and gas production. Journal of Animal Science, 94(3), 1170-1178. doi:10.2527/jas2015-8779Fifty-two Holstein steers (573 +/- 9.92 kg BW) were used to determine if oral administration of crystalline menthol would induce changes in endogenous secretions of IGF-1 and circulating concentrations of glucose, lactate, and plasma urea nitrogen (PUN). Steers were blocked by BW and assigned within block to treatment. Treatments consisted of 0, 0.003, 0.03, or 0.3% crystalline menthol (DM basis) added to the diet. Animals were housed in individual, partially covered pens equipped with feed bunks and automatic water fountains. On d 1 of the experiment, blood samples were obtained via jugular venipuncture at 0, 6, 12, 18, and 24 h after feeding. Treatment administration commenced on d 2, and blood samples were again drawn at 0, 6, 12, 18, and 24 h after feeding. This blood-sampling schedule was repeated on d 9, 16, 23, and 30. Plasma was analyzed for PUN, glucose, and lactate concentrations. Serum was used to analyze IGF-1 concentration. Body weights were measured on d 1, 9, 16, 23, and 30. To accompany the live animal phase, in vitro fermentations were performed using ruminal fluid cultures. Measurements included VFA concentrations and fermentative gas production for cultures containing crystalline menthol at 0, 0.003, 0.03, or 0.3% of substrate DM. Addition of menthol to the diet of steers resulted in a treatment x day interaction (P 0.21). In conclusion, menthol supplementation minimally affected blood parameters associated with growth or ruminal fermentative activity

Effect of extended postmortem aging and steak location on myofibrillar protein degradation and Warner-Bratzler shear force of beef M. semitendinosus steaks

Citation: Phelps, K. J., Drouillard, J. S., Silva, M. B., Miranda, L. D. F., Ebarb, S. M., Van Bibber-Krueger, C. L., . . . Gonzalez, J. M. (2016). Effect of extended postmortem aging and steak location on myofibrillar protein degradation and Warner-Bratzler shear force of beef M. semitendinosus steaks. Journal of Animal Science, 94(1), 412-423. doi:10.2527/jas2015-9862The objective of this study was to evaluate the effect of steak location and postmortem aging on cooked meat tenderness and myofibrillar protein degradation of steaks from M. semitendinosus (ST). Following harvest and a 6 d chill period, the left ST was removed from carcasses of crossbred feedlot steers (n = 60, average hot carcass weight 427 +/- 24 kg). Each ST was fabricated into ten 2.54-cm thick steaks originating from the proximal to distal end of the muscle. Steaks cut adjacent to each other were paired, vacuum packaged, and randomly assigned to 7, 14, 21, 42, or 70 d of aging at 2 +/- 1 degrees C. After aging, within each steak pair, steaks were randomly assigned to Warner-Bratzler shear force or myofibrillar proteolysis analysis (calpain activity and desmin and troponin-T degradation). Muscle fiber type and size were also determined at the 2 ends of the muscle. There was no location x d of aging interaction (P = 0.25) for ST steak WBSF. Steak location affected (quadratic, P 0.13). Type I, IIA, and IIX muscle fibers were larger at the proximal end of the muscle than the distal end (P < 0.01). Increasing d of aging improved WBSF (quadratic, P < 0.01) for the duration of the 70 d postmortem period. As d of aging increased, intact calpain-1 activity decreased (quadratic, P < 0.01) with activity detected through 42 d. Day of aging affected autolyzed calpain-1 (linear, P < 0.01) and calpain-2 activity (quadratic, P < 0.01). Through d 70 of aging, the intensity of intact 55 kDa desmin band decreased (linear, P < 0.01), while there was an increase (linear, P < 0.01) in the degraded 38 kDa band. Similarly, d of aging increased troponin-T proteolysis, indicated by a decrease (quadratic, P < 0.01) in intensity of the intact 40 kDa band and an increase (linear, P < 0.01) in the 30 kDa degraded band. Intramuscular WBSF differences are not due to proteolytic activity or myofibrillar degradation and seem related to muscle fiber size. The improvement of ST steak WBSF through 70 d of aging is partly due to continued degradation of desmin and troponin-T. Calpain proteolytic analysis indicates that autolyzed calpain-1 and calpain-2 may be involved in extended postmortem myofibrillar protein proteolysis

Effect of growth-promoting technologies on Longissimus lumborum muscle fiber morphometrics, collagen solubility, and cooked meat tenderness

Citation: Ebarb, S. M., Drouillard, J. S., Maddock-Carlin, K. R., Phelps, K. J., Vaughn, M. A., Burnett, D. D., . . . Gonzalez, J. M. (2016). Effect of growth-promoting technologies on Longissimus lumborum muscle fiber morphometrics, collagen solubility, and cooked meat tenderness. Journal of Animal Science, 94(2), 869-881. doi:10.2527/jas2015-9888The objective of the study was to examine the effect of growth-promoting technologies (GP) on Longissimus lumborum steak tenderness, muscle fiber cross-sectional area (CSA), and collagen solubility. Crossbred feedlot heifers (n = 33; initial BW 464 +/- 6 kg) were blocked by BW and assigned to 1 of 3 treatments: no GP (CON; n = 11); implant, no zilpaterol hydrochloride (IMP; n = 11); implant and zilpaterol hydrochloride (COMBO; n = 11). Heifers assigned to receive an implant were administered Component TE-200 on d 0 of the study, and the COMBO group received 8.3 mg/kg DM of zilpaterol hydrochloride for the final 21 d of feeding with a 3 d withdrawal period. Following harvest, strip loins were collected and fabricated into 4 roasts and aged for 3, 14, 21, or 35 d postmortem. Fiber type was determined by immunohistochemistry. After aging, objective tenderness and collagen solubility were measured. There was a treatment x day of aging (DOA) interaction for Warner-Bratzler shear force (WBSF; P 0.31). Soluble collagen amount tended to be affected (P = 0.06) by a treatment x DOA interaction which was due to COMBO muscle having more soluble collagen than the other 2 treatments on d 21 of aging (P < 0.02). Correlation analysis indicated that type I, IIA, and IIX fiber CSA are positively correlated with WBSF at d 3 and 14 of aging (P < 0.01), but only type IIX fibers are correlated at d 21 and 35 of aging (P < 0.03). At these time periods, total and insoluble collagen became positively correlated with WBSF (P < 0.01). This would indicate that relationship between muscle fiber CSA and WBSF decreases during postmortem aging, while the association between WBSF and collagen characteristics strengthens. The use of GP negatively impacted meat tenderness primarily through increased muscle fiber CSA and not through altering collagen solubility

Effects of anabolic implants and ractopamine-HCl on muscle fiber morphometrics, collagen solubility, and tenderness of beef longissimus lumborum steaks

Citation: Ebarb, S. M., Phelps, K. J., Drouillard, J. S., Maddock-Carlin, K. R., Vaughn, M. A., Burnett, D. D., . . . Gonzalez, J. M. (2017). Effects of anabolic implants and ractopamine-HCl on muscle fiber morphometrics, collagen solubility, and tenderness of beef longissimus lumborum steaks. Journal of Animal Science, 95(3), 1219-1231. doi:10.2527/jas2016.1263The objective of this study was to examine the effects of growth-promoting technologies (GP) and postmortem aging on longissimus lumborum muscle fiber cross-sectional area (CSA), collagen solubility, and their relationship to meat tenderness. Two groups of black-hided crossbred feedlot heifers (group 1: n = 33, initial BW 430 +/- 7 kg; group 2: n = 32, initial BW 466 +/- 7 kg) were blocked by BW and assigned to 1 of 3 treatments consisting of: no implant and no ractopamine hydrochloride (CON; n = 21); implant, no ractopamine hydrochloride (IMP; n = 22); implant and ractopamine hydrochloride (COMBO; n = 22). Heifers that received an implant were administered an implant containing 200 mg trenbolone acetate and 20 mg estradiol on d 0 of the study, and heifers in the COMBO group received 400 mg.head(-1).d(-1) of ractopamine hydrochloride for 28 (Group 1) or 29 d (Group 2) at the end of 90-(Group 1) or 106-d (Group 2) feeding period. Following harvest, strip loins were collected and further fabricated into 5 roasts for postmortem aging (DOA) periods of 2, 7, 14, 21, or 35 d. After aging, Warner-Bratzler shear force (WBSF), muscle fiber CSA, and collagen solubility were measured. There was no treatment x DOA interaction for WBSF (P = 0.86), but treatment and DOA impacted WBSF (P 0.33). Collagen amounts were not impacted by GP treatment (P > 0.72), but DOA increased the concentration of soluble collagen (P = 0.04). Fiber CSA of all fiber types were positively correlated (P < 0.05; r = 0.21 to 0.28) with WBSF only on d 2 of aging, while soluble collagen amount tended to negatively correlate with WBSF on d 7 and 14 of aging (P < 0.10; r = -0.24 and -0.23, respectively). Administration of GP during heifer finishing resulted in greater steak WBSF over 35 d of aging, which was not due to collagen characteristics and only minimally affected by fiber CSA

Effects of Menthol Supplementation in Feedlot Cattle Diets on the Fecal Prevalence of Antimicrobial-Resistant <i>Escherichia coli</i>

<div><p>The pool of antimicrobial resistance determinants in the environment and in the gut flora of cattle is a serious public health concern. In addition to being a source of human exposure, these bacteria can transfer antibiotic resistance determinants to pathogenic bacteria and endanger the future of antimicrobial therapy. The occurrence of antimicrobial resistance genes on mobile genetic elements, such as plasmids, facilitates spread of resistance. Recent work has shown <i>in vitro</i> anti-plasmid activity of menthol, a plant-based compound with the potential to be used as a feed additive to beneficially alter ruminal fermentation. The present study aimed to determine if menthol supplementation in diets of feedlot cattle decreases the prevalence of multidrug-resistant bacteria in feces. Menthol was included in diets of steers at 0.3% of diet dry matter. Fecal samples were collected weekly for 4 weeks and analyzed for total coliforms counts, antimicrobial susceptibilities, and the prevalence of <i>tet</i> genes in <i>E</i>. <i>coli</i> isolates. Results revealed no effect of menthol supplementation on total coliforms counts or prevalence of <i>E</i>. <i>coli</i> resistant to amoxicillin, ampicillin, azithromycin, cefoxitin, ceftiofur, ceftriaxone, chloramphenicol, ciprofloxacin, gentamicin, kanamycin, nalidixic acid, streptomycin, sulfisoxazole, and sulfamethoxazole; however, 30 days of menthol addition to steer diets increased the prevalence of tetracycline-resistant <i>E</i>. <i>coli</i> (<i>P</i> < 0.02). Although the mechanism by which menthol exerts its effects remains unclear, results of our study suggest that menthol may have an impact on antimicrobial resistance in gut bacteria.</p></div