[Show abstract][Hide abstract] ABSTRACT: The objective of this study was to evaluate the influence of corn silage (CS) or sugar cane (SC) additions to finishing diets on voluntary intake, apparent digestibility, animal performance, and LM fatty acid (FA) composition in crossbred Holstein × Zebu bulls. Forty-two bulls (initial BW 328 ± 39.2 kg and an initial age of 23.5 mo) were utilized in this experiment. A completely randomized design was used to examine roughage source (CS vs. SC) and ratio of concentrate (CO) on nutrient utilization and production. The experimental diets consisted of: 1) 60% CS:40% CO fed for 84 d (CS 60:40), 2) 60% CS:40% CO fed for 42 d and 40% CS:60% CO fed for 42 d - CS reverse diet (CSR), 3) 40% CS:60% CO fed for 84 d (CS 40:60), 4) 60% SC:40% CO fed for 84 d (SC 60:40), 5) 60% SC:40% CO fed for 42 d and 40% SC:60% CO fed for 42 d - SC reverse diet (SCR), and 6) 40% SC:60% CO fed for 84 d (SC 40:60). Dry matter and NDF intakes were greater (P < 0.01) in bulls fed CS-based diets than bulls fed SC-based diets. The greatest (P < 0.01) DM and CP digestibility were observed in bulls fed SC-based diets. Bulls fed CSR and CS 40:60 had greater (P < 0.01) ADG than bulls fed SC-based diets. However, ADG was similar (P = 0.52) in bulls fed CS 60:40, CSR, and SC 40:60 diets. The percentage of C18:3(n-3) and C20:5(n-3) were greater (P < 0.01) in LM of bulls fed SC-based diets. The percentage of CLA was greater (P < 0.01) in LM of bulls fed SC 60:40 than those fed CS-based diets. The findings of the present study indicate that SC 40:60 can replace CS 60:40 and CSR in finishing diets and moreover, roughage source significantly altered the FA composition of crossbred Holstein × Zebu bulls LM.
Journal of Animal Science 04/2014; · 2.09 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: To determine if supplementation of omega (ώ)-3 long chain polyunsaturated fatty acid (LCPUFA) alters synovial fluid fatty acid composition and prostaglandin E2 (PGE2) concentration of mature, healthy horses.: Twenty, non-pregnant light breed mares were assigned into one of three daily dietary treatments. Group 1 (MARINE) received 38g total of the ώ-3 LCPUFA alpha linolenic acid (ALA, 2g), eicosapentaenoic acid (EPA, 7.6g) and docosahexaenoic acid (DHA, 26.6g) via a marine-derived supplement; Group 2 (FLAX) received 38g of ώ-3 ALA via a flaxseed supplement and Group 3 (CONT) did not receive additional ώ-3 LCPUFA. Blood was taken at baseline, 30, 60, and 90 days of supplementation and plasma separated. After of 90 days of supplementation, 3 ml of synovial fluid was obtained through arthrocentesis. Plasma and synovial fluid were analyzed to identify fatty acid profiles, and determine PGE2 concentration. MARINE synovial fluid fatty acids contained higher of EPA and DHA compared to the CONT group; and higher DHA levels compared to FLAX group. EPA was not detected in synovial fluid from the FLAX group. Prostaglandin E2 did not differ (P>0.05) among horses; however, the MARINE group tended (P=0.10) to have lower synovial PGE2 concentration compared to CONT horses. The presence of EPA and DHA only in MARINE synovial fluid and plasma suggests direct supplementation of EPA and DHA is needed to modify fatty acid composition. A tendency for lower synovial PGE2 in healthy horses receiving oral EPA/DHA merits further investigation in the ώ-3 supplementation effect on prostaglandin production.
Journal of Equine Veterinary Science 01/2014; · 0.62 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The present experiment was designed to evaluate the use of microbial markers (MM), sampling sites (SS), and marker systems (MS) to estimate microbial nitrogen (MN) synthesis in bulls and to develop equations to correct MN estimates when only one of the aforementioned techniques was utilized. The MM systems evaluated were 1) purine bases (PB) and 2) 15N labeling. The SS evaluated were: 1) reticulum, 2) omasum, and 3) abomasum, and the single, double and triple MS were evaluated. Eight crossbred (Holstein×Zebu) bulls (353±36.9 kg of BW; 24±1 mo) with ruminal and abomasal cannulas were utilized in this experiment. The following experimental diets were used: 1) 60% corn silage+40% concentrate, 2) 40% corn silage+60% concentrate, 3) 60% fresh sugarcane+40% concentrate, and 4) 40% fresh sugarcane+60% concentrate. Four experimental periods lasting 16 d each were completed with 10 d for adaptation to the experimental diet and 6 d for sampling. Bulls were randomly distributed into two 4×4 Latin squares balanced for residual effects. Data were analyzed in a Latin square design using PROC MIXED. Interactions were observed (P<0.05) in MN, microbial crude protein/total digestible nutrients (MCP/TDN), microbial nitrogen/rumen fermented organic matter (MN/RFOM), microbial nitrogen/rumen truly fermented organic matter (MN/RTFOM), and microbial dry matter/rumen fermented total carbohydrates (MDM/RFTCHO) between SS and MM. For PB, the greatest (P<0.01) values of MN were observed for the digesta sampled in the reticulum and abomasum. In contrast, for 15N, the greatest (P<0.01) values were observed for digesta sampled in the omasum and abomasum. Microbial nitrogen yield was only different (P<0.05) when using reticulum and 15N from those estimated using abomasum and 15N. Thus, the equation developed to correct MN value was: MN (g/d)=27.93±2.46+0.99±0.09×reticulum 15N. The triple MS exhibited the greatest (P<0.01) value of MN compared to the single and double MS. No interactions (P>0.05) were observed between MS and MM or SS; thus, the equation established to correct MN value used only the MS. In conclusion, we have demonstrated that there is no difference using 15N to estimate MN yield if omasum or abomasum are used. Therefore, the omasum can be used as an accurate SS to predict MN. The triple MS presented higher values than the single and double MS. Thus, if single or double MS is used the value must be corrected by the equation obtained using the triple MS.
[Show abstract][Hide abstract] ABSTRACT: The objectives of this study were to evaluate the effects of castration method (banding vs. surgical) and use of analgesia on behavior and feedlot performance in cull bulls. Angus, Hereford, and Angus-crossbred bulls (n = 20; initial BW = 384 ± 59.3 kg; 336 ± 20.1 d old) were housed in feedlot pens equipped with the ability to measure individual daily feed intake. A balanced randomized block design using a 2 × 2 factorial arrangement of treatments was utilized. A multimodal analgesia protocol (MMA) was used and consisted of s.c. ketamine-stun containing butorphanol (0.01 mg/kg BW), xylazine (0.02 mg/kg BW), ketamine (0.04 mg/kg BW), and a local 2% lidocaine hydrochloride anesthetic block of the spermatic cords (10 mL/cord) and scrotum (10 mL) on d 0. Flunixin meglumine (1.2 mg/kg) was administered i.v. on d 0, 1, 2 and 3 to MMA cattle. Cattle were stratified to treatments based on breed, BW, age, and a temperament score. Treatments included: 1) band castration without analgesia (BND); 2) band castration with analgesia (BND-MMA); 3) surgical castration without analgesia (SURG); and 4) surgical castration with analgesia (SURG-MMA). All castrations were performed on d 0. Chute exit velocity (EV) and time in chute (TIC) were collected on d -9, 0, 1, 2, and 13. Willingness-to-enter-chute (WTE) score, rectal temperature (TEMP), heart rate (HR), and respiration (RESP) were collected on d 0, 1, 2, 3, and 13. Cattle were weighed on d -9 and 13 while feeding behaviors were collected continuously for 57 d pre-castration and 28 d post-castration. There was a tendency (P < 0.09) for ADG to be greater in cattle receiving analgesia. Both SURG treatments exhibited elevated TEMP on d 1 (P < 0.001) and 2 (P < 0.05) compared to BND treatments. Post-castration DMI was greater (P = 0.02) in MMA treatments compared with non-medicated treatments throughout the trial. Meal duration was greater (P < 0.05) in BND than SURG castrates during the first week post-castration. Results suggest that pain mitigation reduces the impact of castration on ADG and DMI.
Journal of Animal Science 08/2013; · 2.09 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Two experiments evaluated the effects of band castration and oral administration of an analgesic in association with castration on performance and behavioral and physiological responses in yearling beef bulls. In Exp. 1 Angus and Charolais-crossbred bull calves (n = 127; 309.8 ± 59.04 kg) and in Exp. 2 Hereford, Angus, and Hereford × Angus crossbred bulls (n = 30; 300.8 ± 4.96 kg), were stratified by BW and randomly assigned to 1 of 3 treatments: 1) band castration (BAND), 2) band castration with oral administration of meloxicam (BAND-MEL), and 3) sham castration (SHAM). The BAND and SHAM procedures were completed on d 0. The SHAM treatment consisted of all animal manipulations associated with band castration without band application. Meloxicam was administered on d -1, 0, and 1 (1.0 mg/kg, 0.5 mg/kg and 0.5 mg/kg, respectively) via an oral bolus. Body weight and a subjective chute score (CS) were collected on d -1, 0, 1, 7, 14, and 21 (d 28 Exp. 1 only). In Exp. 2, jugular blood samples were collected immediately before castration and 24 hr post-castration for Substance P (SP) analysis. In Exp. 2, video documentation on d 0 was used to determine range of vertical head motion (DIST) on a subset of animals during treatment administration. In both experiments, ADG was similar (P ≥ 0.50) between BAND and BAND-MEL, but ADG in SHAM cattle was greater (P < 0.001) and tended (P = 0.07) to be greater than castrates in Exp. 1 and 2, respectively. In Exp. 1, CS did not differ (P ≥ 0.26) between BAND and BAND-MEL on any d, but castrates exhibited less desirable CS on d 1 and 28 than SHAM cattle. In Exp. 2, CS was not affected (P ≥ 0.41) by castration or the presence of meloxicam. In Exp. 2, DIST did not differ (P = 0.57) between BAND and BAND-MEL, but when pooled, castrates exhibited greater (P = 0.04) DIST than SHAM. In Exp. 2, plasma SP concentrations were similar between BAND and BAND-MEL (P = 0.81), and castrates vs. sham cattle (P = 0.67). Results indicate no impact of meloxicam administration on performance or behavioral and physiological responses to band castration. However, there was a negative impact of castration on ADG and DIST.
Journal of Animal Science 07/2013; · 2.09 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The objective of this study was to examine the effects of dietary ω-3 fatty acid supplementation on insulin sensitivity (SI) in horses. Twenty-one mares were blocked by age, body weight (BW), and body condition score (BCS) and randomly assigned to one of three dietary treatments. Treatments consisted of (1) 38 g of n-3 fatty acids via fish and algae supplement and diet (MARINE), (2) 38 g of n-3 fatty acids via a flaxseed meal from the supplement and diet (FLAX), and (3) control (CON) no supplemental fatty acid. Treatments were supplemented for 90 days. Frequent sampling intravenous glucose tolerance tests were performed on days 0, 30, 60, and 90. Blood samples were analyzed for glucose and insulin. The minimal model was applied for the glucose and insulin curves using MinMod Millennium. SI increased 39% (P < .007) across all treatment groups. Acute insulin response to glucose decreased 22% (P < .006) between days 30 and 60 and increased (P = .040) again at day 90. Disposition index (combined SI and β pancreatic response) increased (P = .03) by 53% in the MARINE- and 48% in the FLAX-supplemented horses and did not change with time in the CON group. In insulin-resistant mares, MARINE- and FLAX-treated horses had an increase in SI (P = .09). It would be interesting to test this supplement in a larger group of insulin-resistant horses. If proven effective, supplementation with ω-3 fatty acids would help to reduce problems associated with insulin resistance in horses.
[Show abstract][Hide abstract] ABSTRACT: Beef nutrition is important to the worldwide beef industry. The objective of this study was to analyze proximate composition of eight beef rib and plate cuts to update the USDA National Nutrient Database for Standard Reference (SR). Furthermore, this study aimed to determine the influence of USDA Quality Grade on the separable components and proximate composition of the examined retail cuts. Carcasses (n=72) representing a composite of Yield Grade, Quality Grade, gender and genetic type were identified from six regions across the U.S. Beef plates and ribs (IMPS #109 and 121C and D) were collected from the selected carcasses and shipped to three university meat laboratories for storage, retail fabrication, cooking, and dissection and analysis of proximate composition. These data provide updated information regarding the nutrient content of beef and emphasize the influence of common classification systems (Yield Grade and Quality Grade) on the separable components, cooking yield, and proximate composition of retail beef cuts.
[Show abstract][Hide abstract] ABSTRACT: The objective of this study was to generate raw and cooked nutrient composition data to identify Quality Grade differences in proximate values for eight Beef Alternative Merchandising (BAM) cuts. The data generated will be used to update the nutrient data in the USDA National Nutrient Database for Standard Reference (SR). Beef Rib, Oven-Prepared, Beef Loin, Strip Loin, and Beef Loin, Top Sirloin Butt subprimals were collected from a total of 24 carcasses from four packing plants. The carcasses were a combination of USDA Yield Grades 2 (n=12) and 3 (n=12), USDA Quality Grades upper two-thirds Choice (n=8), low Choice (n=8), and Select (n=8), and two genders, steer (n=16) and heifer (n=8). After aging, subprimals were fabricated into the BAM cuts, dissected, and nutrient analysis was performed. Sample homogenates from each animal were homogenized and composited for analysis of the following: proximate analysis, long chain and trans-fatty acids, conjugated linoleic acid, total cholesterol, vitamin B-12, and selenium. This study identified seven BAM cuts from all three Quality Grades that qualify for USDA Lean; seven Select cuts that qualify for USDA Extra Lean; and three Select cuts that qualify for the American Heart Association's Heart Healthy Check.
[Show abstract][Hide abstract] ABSTRACT: Observations were collected for the purpose of comparing exit velocity measurements: exit score (ES; walk, trot, canter, or run) and flight speed (FS) as assessments of cattle temperament. Squeeze chute exit velocity was obtained for 1,181 crossbred yearling steers using ES and FS temperament systems. Flight speed utilized infrared sensors to determine the time taken for an animal to traverse a fixed distance of 1.83 m after exiting the squeeze chute. Exit score (1 = walk, 2 = trot, 3 = canter, and 4 = run) was assigned by 2 different observers when each steer crossed a fixed point between the infrared sensors. All animals were scored with each system (ES and FS) simultaneously upon exiting the squeeze chute on d -21 and d -1 of the experiment. Of the 1,181 cattle, 357 were moved to a nearby research feedyard for use in a 140 d feedlot trial. These cattle were scored using both measurement systems and BW was recorded at 35 d intervals throughout the trial. Exit score was assessed for observer reliability, ES and FS were compared for measurement repeatability, and both were assessed on ability to predict ADG. Exit score between observers on a single day showed considerable agreement (weighted Kappa = 0.66) indicating the system was reliable between different observers. However, the agreement for a single observer between day was only moderate (weighted Kappa = 0.40), indicating a day effect for ES. In addition, although mean velocities for day were not different (P > 0.18; FS = 2.98 ±.87 and 3.02 ± 0.87 m/s for day respectively), the persistence of FS for each animal was low (Spearman rank correlation coefficient = 0.25). The frequency that an animal would be placed into the same third of FS or receive the same ES on consecutive weigh days was 50% and 60.0% respectively, and both were moderate predictors of ADG (R(2) = 0.14 and R(2) = 0.17). These data indicate that ES and FS are reliable instruments for assessment of temperament on a given day, and show moderate repeatability across days. Exit score and FS show similar ability to predict ADG and can be used interchangeably as measures of temperament.
Journal of Animal Science 10/2012; · 2.09 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Thirty-three colostrum-deprived Holstein bull calves (initial BW of 131 ± 4 kg) were used to determine the effect of timing of anthelmintic administration relative to vaccination on antibody titer response to vaccine component antigens. When calves were at least 3 mo of age, they were sorted randomly into individual pens and assigned to 1 of 3 treatment groups, treatments consisted of 1) dewormed 2 wk before vaccination (DPV), 2) dewormed at the time of vaccination (DV), or 3) control, vaccinated but not dewormed (CONT). All calves were inoculated with infective larvae of brown stomach worms (Ostertagia ostertagi) and intestinal worms (Cooperia spp.) on d 1, 7, 10, 14, and 18 for a total dose of 235,710 infective larvae per calf. Calves (DPV and DV) were dewormed on d 21 or 35 with a 10% fenbendazole suspension at 5 mg/kg of BW. On d 35, all calves were vaccinated with a modified-live virus respiratory vaccine containing IBRV (infectious bovine rhinotracheitis virus), BVDV-1 (bovine viral diarrhea virus genotype 1), BVDV-2 (BVDV genotype 2), PI-3 (parainfluenza-3), and BRSV (bovine respiratory syncytial virus). During the 103-d experiment, weekly fecal egg counts, blood, and rectal temperatures were collected and health status was recorded daily. Blood samples were obtained weekly to determine serum neutralizing (SN) antibody titers to IBRV, BVDV-1, BVDV-2, and PI-3 and cytokine levels for IL-4, IL-6, TNF-α (tumor necrosis factor-α), and IFN-γ (interferon-gamma). There was a tendency (P < 0.09) for CONT calves to have greater IL-4 concentrations. By design, control calves had greater (P < 0.01) fecal egg counts during the experiment. All calves developed antibody titers to IBRV, BVDV-1, BVDV-2, and PI-3 by d 15 postvaccination. On d 88, all calves were challenged with IBRV and blood samples were obtained on d 88, 89, 90, 93, 95, 98, 99, and 103. All calves had increased rectal temperatures during the final 7 d of the IBRV challenge. However, the CONT group had greater (P < 0.01) rectal temperatures on each sampling day except d 90 compared with the DPV and DV treatments. Therefore, deworming before or at vaccination reduced parasite burden and decreased rectal temperature increase after an IBRV challenge. Deworming strategy had no effect on antibody response to vaccination or IBRV challenge.
Journal of Animal Science 06/2012; 90(6):1948-54. · 2.09 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The objective of this experiment was to determine if dietary inclusion of fish meal would increase plasma and luteal tissue concentrations of eicosapentaenoic and docosahexaenoic acids. Seventeen nonlactating Angus cows (2 to 8 yr of age) were housed in individual pens and fed a corn silage-based diet for approximately 60 d. Diets were supplemented with fish meal at 5% DMI (a rich source of eicosapentaenoic acid and docosahexaenoic acid; n = 9 cows) or corn gluten meal at 6% DMI (n = 8 cows). Body weights and jugular blood samples were collected immediately before the initiation of supplementation and every 7 d thereafter for 56 d to monitor plasma n-3 fatty acid composition and BW. Estrous cycles were synchronized using 2 injections of PGF(2α) administered at 14-d intervals. The ovary bearing the corpus luteum was surgically removed at midcycle (between d 10 and 12) after estrus synchronization, which corresponded to approximately d 60 of supplementation. The ovary was transported to the laboratory, and approximately 1.5 g of luteal tissue was stored at -80°C until analyzed for n-3 fatty acid content. Initial and ending BW did not differ (P > 0.10) between cows supplemented with fish meal and those with corn gluten meal. Plasma eicosapentaenoic acid was greater (P < 0.05) beginning at d 7 of supplementation and docosahexaenoic was greater (P < 0.05) beginning at d 14 of supplementation for cows receiving fish meal. Luteal tissue collected from fish meal-supplemented cows had greater (P < 0.05) luteal n-3 fatty acids and reduced (P < 0.05) arachidonic acid and n-6 to n-3 ratio as compared with tissue obtained from cows supplemented with corn gluten meal. Our data show that fish meal supplementation increases luteal n-3 fatty acid content and reduces available arachidonic acid content, the precursor for PGF(2α). The increase in luteal n-3 fatty acids may reduce PGF(2α) intraluteal synthesis after breeding resulting in increased fertility in cattle.
Journal of Animal Science 03/2012; 90(3):771-8. · 2.09 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The objective of this study was to determine the optimal postmortem aging period and nutrient composition for Beef Value Cuts of the round. Forty USDA Select and 40 Premium USDA Choice beef carcasses were selected from a commercial beef packing plant in Colorado over a 12-wk period. The bottom and inside rounds were collected from both sides of each carcass for further fabrication into the following muscles: adductor, gastrocnemius, gracilis, pectineus, and superficial digital flexor. Each pair of muscles was cut into 7 steaks and randomly assigned to 1 of the following aging periods: 2, 4, 6, 10, 14, 21, and 28 d, and placed in refrigerated storage (2°C, never frozen). Upon completion of the designated aging period, steaks were removed from storage, cooked to a peak internal temperature of 72°C, and evaluated using Warner-Bratzler shear force (WBSF). A 2-way interaction was detected (P < 0.05) between individual muscle and postmortem aging period. The WBSF of all muscles except the superficial digital flexor decreased with increased time of postmortem aging. Quality grade did not affect (P > 0.05) WBSF values for the adductor, gastrocnemius, pectineus, and superficial digital flexor muscles. Exponential decay models were used to predict the change in WBSF from 2 to 28 d postmortem (aging response). The adductor, gastrocnemius, Select gracilis, Premium Choice gracilis, and pectineus required 21, 14, 23, 23, and 25 d, respectively, to complete the majority of the aging response. To determine the nutrient composition of the adductor, gastrocnemius, gracilis, pectineus, semimembranosus, and superficial digital flexor, bottom and inside rounds were collected from 10 USDA Select and 10 Premium USDA Choice carcasses and fabricated into the respective muscles, cut into 2.54-cm cubes, frozen (-20°C), and then homogenized. The adductor, gracilis, pectineus, semimembranosus, and superficial digital flexor were analyzed for DM, moisture, CP, and ash percentages. All muscles were evaluated for total lipid, fatty acid, and cholesterol composition. When quality grades were combined, all muscles fell into the extra lean or lean categories specified by USDA guidelines. Results of this study illustrate the potential for Beef Value Cuts of the round to be sold in food service operations and retail stores with marketing emphasis being placed on the exceptional leanness and acceptable tenderness of these cuts.
Journal of Animal Science 03/2012; 90(3):996-1007. · 2.09 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Data from 4 separate beef cattle feedlot experiments, which were conducted at the Southeast Colorado Research Center (SECRC) in Lamar, CO, in 2001, 2003, 2004, and 2007, were utilized in a retrospective longitudinal study investigating possible relationships between daily water consumption (WC), DMI, and weather variables. The data set consisted of 8,209 records from 2001, 2003, 2004, and 2007, with pen based daily WC (L•animal(-1)) and DMI measurements and calculated daily steer BW from April to October in each year. Daily weather data were obtained from the weather station located at Lamar Municipal Airport located approximately 1.9 km from SECRC. Data collected consisted of daily high, low, and mean temperature; high, low, and mean humidity; high, low, and mean sea level pressure; mean wind speed; total precipitation; and average daily wind direction (cosine of radians from due north). Univariate analysis demonstrated that the continuous variables of BW, humidity, and sea level pressure were negatively related (P < 0.0001), whereas DMI, temperature the previous day, daily temperature, change in temperature from the previous day, average wind speed, and the temperature-humidity index (THI) were positively related (P < 0.001) to daily WC. There was a trend (P < 0.06) for the cosine of wind direction (1 = due north and -1 = due south) to be negatively related to WC. The multivariate, parsimonious model predicting average daily WC included (P < 0.05) average humidity, average humidity squared, high temperature squared, high humidity squared, low temperature, low temperature squared, low humidity, average sea level pressure, average wind speed, average daily BW, high sea level pressure, low sea level pressure, high humidity, and low humidity. The generalized R(2) of the parsimonious multivariate model was 0.32. These results indicate that BW and numerous weather factors are related to WC by yearling feedlot steers. Dry matter intake had minimal impact on WC for yearling feedlot steers consuming steam-flaked corn-based high concentrate diets from mid-spring to early fall.
Journal of Animal Science 12/2011; 90(6):1920-8. · 2.09 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Sixty finishing lambs (BW=41.6±1.4kg) were utilized to investigate the effects of replacing carbohydrate-based energy with calcium salts of fatty acids (CSFA) on finishing lamb feedlot performance, blood metabolites, muscle fatty acid composition, and carcass characteristic. Upon arrival, lambs were weighed on 2 consecutive days and randomly assigned to 1 of 4 dietary concentrations of CSFA. Treatments included: (1) 0% CSFA (control); (2) 4% CSFA; (3) 7% CSFA and (4) 11% CSFA on a DM basis. Diets were formulated to be isoenergetic (TDN basis) and isonitrogenous (DIP and UIP) and consisted of 75% concentrate, and 25% roughage (corn silage). Rations had comparable levels of dietary TDN; rations with less corn had a higher concentration of CSFA-pellet. Intake was controlled to balance TDN per kg of BW across treatments; all treatments met 2006 NRC requirements for growing lambs. Lambs were weighed and bled every 14±2d. Blood samples were analyzed for glucose, lactate and insulin concentrations. On d 62, lambs were transported to a commercial abattoir and slaughtered. Hot carcass weight (HCW) was determined at the time of slaughter, and longissimus muscle (LM), and liver and subcutaneous adipose tissue samples were collected and snap-frozen for later analysis. Longissimus muscle area (LMA) and back fat (BF) carcass measurements were determined after a 48h chill at 4°C. There was a treatment effect for ADG, DMI and gain to feed efficiency (P
Small Ruminant Research - SMALL RUMINANT RES. 01/2011; 95(2):97-103.
[Show abstract][Hide abstract] ABSTRACT: A 4 × 2 factorial arrangement of treatments (4 growth-enhancement treatments × 2 sex classes) was used to quantify effects of initial implanting (I-implant, d 0), terminal implanting (T-implant, d 63), and feeding ractopamine hydrochloride [RAC, 200 mg/(animal/d)] for the last 28 d on feed on carcass characteristics and LM shear force (WBSF) of calf-fed steers (n = 159) and heifers (n = 132). Growth-enhancement treatments included the following: TRT1, T-implant only; TRT2, I-implant and RAC; TRT3, I-implant and T-implant; TRT4, I-implant, T-implant, and RAC. Growth responses (BW and ADG) were measured in 3 segments of the finishing period: 1) d 0 to 63, 2) d 63 to 28 d before slaughter, and 3) final 28 d. Cattle were slaughtered after 152, 166, or 180 d of finishing; carcass data were collected after a 48-h chill; and LM WBSF was measured at 3, 7, 14, 21, and 28 d postmortem. A priori contrasts were constructed to test effects associated with use vs. exclusion of growth enhancement in each segment of the finishing period. The interaction between sex class and treatment was not significant (P > 0.05) for any trait tested, indicating that the 4 treatments elicited similar effects in both sexes. Initial implanting improved (P < 0.001) ADG from d 0 to 63 by 11.5%, terminal implanting improved (P < 0.001) ADG from d 63 to 28 d before slaughter by 15%, and supplementing twice-implanted cattle with RAC enhanced ADG during the final 28 d of finishing by 12%. Effects of I-implant, T-implant, and RAC resulted in LM area increases of 3 cm(2) (P = 0.015), 6 cm(2) (P < 0.001), and 3 cm(2) (P = 0.011), respectively, and HCW responses of 11 kg (P = 0.011), 16 kg (P = 0.001), and 6 kg (P = 0.195), respectively. Initial implanting resulted in a 20-point reduction (P = 0.097) in marbling, and T-implant reduced marbling by 25 points (P = 0.04), whereas marbling score was unaffected (P = 0.236) by RAC supplementation. Cattle that received only 1 implant (TRT1 and TRT2) produced carcasses with greater (P = 0.026) mean marbling scores and greater (P = 0.01) rates of conformity to beef carcass marketing specifications for HCW, quality grade, yield grade, and LM area than did cattle that were implanted twice (TRT3 and TRT4). Values for LM WBSF were not affected (P > 0.05) by initial or terminal implanting; however, RAC supplementation increased (P = 0.007) mean LM WBSF by 0.23 kg, which translated into a reduction (P = 0.007) in predicted consumer acceptance of LM steaks.
Journal of Animal Science 01/2011; 89(1):201-9. · 2.09 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Reducing crude protein (CP) in livestock diets may lower ammonia emissions. A feeding trial was conducted with crossbred steers at the Southeast Colorado Research Center in Lamar, Colorado from December 2009 to March 2010. Three diet treatments were investigated: Reduced (11.6% CP), Oscillating (13.5% crude protein 4 days/week and 11.6% CP 3 days/week) and Control (13.5% CP). Intact soil core samples (n = 36 per sampling date) were collected from the pen surfaces on three dates corresponding to 45, 92, and 148 days into the feeding cycle. Four pens from each diet treatment were sampled. Cores were placed into flow-through laboratory chambers for seven days and ammonia fluxes were trapped in acid bubblers that were refreshed every 24 h. Average daily ammonia emissions for the Control diet ranged from 6.6 to 9.4 g NH 3 m −2 ·day −1 ; average daily emission for the Oscillating diet ranged from OPEN ACCESS Atmosphere 2011, 2 656 6.3 to 8.8 g NH 3 m −2 ·day −1 ; and average daily flux for the Reduced diet ranged from 4.1 to 5.8 g NH 3 m −2 ·day −1 . Ammonia fluxes from the reduced N treatment were significantly lower (21% to 40%) than from the control diet on the first two sample dates. There was no significant difference between the Oscillating and Control treatments. Reducing CP in cattle feedlot diets may be an effective method for reducing ammonia emissions from pen surfaces. More research is needed to validate these results at commercial scales in different environments to determine if reductions in ammonia can be sustained with lower CP diets without affecting rate of gain, feed efficiency and health.
[Show abstract][Hide abstract] ABSTRACT: Two experiments were conducted to evaluate effects of ractopamine (RAC) and steroidal implant treatments on performance, carcass traits, blood metabolites, and lipogenic enzyme activity in feedlot cattle. In Exp. 1, yearling steers (n = 486; initial BW = 305 kg) were used in a 3 × 3 factorial arrangement of RAC doses of 0 (R0), 100 (R100), or 200 (R200) mg·steer(-1)·d(-1) fed for 28 d and implant regimens (implant-reimplant) of no implant-no reimplant (NI-NI), 120 mg of trenbolone acetate (TBA) and 24 mg of estradiol-17β (E17B)-no implant (RS-NI), or 80 mg of TBA and 16 mg of E17B followed by 120 mg of TBA and 24 mg of E17B (RI-RS). Except for KPH and skeletal maturity score, no RAC × implant interactions were noted (P > 0.10). Carcasses from R200 were 6.3 kg (P = 0.042) heavier than those from R0. Marbling, calculated empty body fat (EBF), and USDA quality grade did not differ (P > 0.10) among RAC treatments. The RI-RS steers had 12.6 kg (P = 0.001) and 41.1 kg (P < 0.001) greater HCW than RS-NI and NI-NI, respectively. Despite no difference (P > 0.10) in EBF, marbling score was decreased for RI-RS (P < 0.001) and RS-NI (P = 0.001) relative to NI-NI, resulting in 14.6 and 11.4 percentage unit fewer USDA Prime and Choice carcasses with RI-RS (P = 0.008) and RS-NI (P = 0.039) than with NI-NI. In Exp. 2, heifers (n = 48; initial BW = 347 kg) were used in a 3 × 2 factorial arrangement of RAC doses of 0 (R0) or 250 (R250) mg·heifer(-1)·d(-1) and implant regimens of none (NI), 200 mg of TBA (TO), or 200 mg of TBA and 20 mg of E17B (TE). Blood samples were collected at various times during the feeding period, and subcutaneous adipose samples were collected on d 119. For growth and carcass measurements, no RAC × implant interactions (P > 0.10) were detected. The RAC-supplemented heifers had greater HCW (P < 0.10) with no difference in marbling score. For implant regimens, TE heifers had greater HCW than the NI (P = 0.001) and TO (P = 0.037) heifers. Although EBF did not differ among implant treatments (P > 0.10), TE (P = 0.021) and TO (P = 0.039) had fewer Choice carcasses than NI. Heifers with implants had decreased cortisol and increased IGF-1 and NEFA (P < 0.10) compared with NI heifers. An implant × RAC interaction was detected (P = 0.001) for serum urea nitrogen (SUN), with TE and RAC-supplemented heifers having decreased SUN. These data suggest that the effects of implant and RAC on growth and carcass traits are independent and that USDA quality grade and marbling score can differ significantly among carcasses with similar calculated EBF values.
Journal of Animal Science 12/2010; 88(12):4102-19. · 2.09 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Increasing dietary electrolyte balance (dEB) has previously been shown to reduce the incidence of nonambulatory and noninjured swine, improve meat quality, and reduce the incidence of gastric ulcers. The objective of this study was to evaluate the effect of dEB under commercial conditions. Due to the variability in feed withdrawal, transport, and lairage conditions in the swine industry, it was necessary to determine first the persistence of blood changes during the marketing process after alteration of dEB. Sixteen pens of 8 crossbred barrows were assigned to a low (121 mEq/kg) or high (375 mEq/kg) dEB diet, calculated as Na(+) + K(+) - Cl(-), to determine the persistence of blood changes associated with the alteration of dEB. Diets were formulated to meet or exceed NRC (1998) requirements for energy, protein, vitamins, and minerals. Dietary treatments were provided for ad libitum intake for 3 d before slaughter. Before transport, animals were fasted in the barn for approximately 10 h. After fasting, animals were shipped to the packing plant, rested for 8 h, and subsequently slaughtered. Initial and final BW of the animals were obtained. Blood was sampled at baseline (2 d before administration of diets), before feed withdrawal (0 h), after feed withdrawal (10 h), and at exsanguination (20 h). Consumption of the high dEB diet for 3 d resulted in an increase in blood TCO(2) (P = 0.001), HCO(3)(-) (P = 0.001), and base excess (P = 0.0003) and a decrease in Cl(-) (P = 0.0002) and anion gap (P = 0.01). These differences, however, were not maintained for any of the blood components after the 10-h feed withdrawal (P > 0.22). Increasing dEB had no adverse effects (P > 0.18) on growth performance, meat quality, or carcass yield and did not decrease pars esophageal ulcer scores. This study demonstrated that the effect of dEB on blood components was not maintained after a 10-h feed withdrawal. Therefore, it is likely that the ability of the animal to withstand any increased metabolic acid load associated with the stress of transport was lost after feed withdrawal. Further research is needed to determine the effects of dEB alteration in animals that have not been fasted before shipment and using diets with a larger difference in dEB.
Journal of Animal Science 12/2010; 88(12):4068-77. · 2.09 Impact Factor