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

Fifty-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 × day interaction ( < 0.01) for concentrations of IGF-1, PUN, and plasma glucose. Cattle fed 0 and 0.003% menthol had greater serum IGF-1 concentrations on d 2 compared with steers fed 0.03% menthol. Steers fed 0% menthol had greater serum IGF-1 concentrations on d 9 compared with steers fed 0.03 and 0.3% menthol, whereas no differences were observed on d 23 or 30. Plasma glucose was similar among treatments until d 23, when steers supplemented with 0.03% menthol had lower glucose concentrations. Plasma urea nitrogen concentrations were not different among treatments; however, PUN concentrations varied by day. A linear response was detected for BW ( = 0.03), with steers consuming 0% menthol having the greatest BW and steers that consumed 0.3% menthol having the lightest BW until d 30. A menthol × day interaction was observed for daily feed deliveries ( < 0.01): cattle fed 0.3% menthol consumed less feed from d 5 through 12. Furthermore, in vitro gas production and VFA concentrations were unaffected by addition of menthol ( > 0.21). In conclusion, menthol supplementation minimally affected blood parameters associated with growth or ruminal fermentative activity.

Effects of feeding diets rich in α-linolenic acid and copper on performance, carcass characteristics, and fatty acid profiles of feedlot heifers.

Our objective was to evaluate whether feeding elevated Cu concentrations in conjunction with Linpro, a co-extruded blend of field peas and flaxseed, affected in vitro fermentation, performance, and plasma lipid profiles of fattening beef heifers. In study 1, 2 in vitro trials were conducted as randomized complete experiments with a 2×2 factorial treatment arrangement (10 or 100 mg/kg added Cu and 0 or 10% Linpro, DM basis) to determine VFA/gas production and IVDMD. Linpro contains 12% α-linolenic acid and added vitamins and minerals. In study 2, a randomized complete block experiment with a 2×2 factorial treatment arrangement was conducted with the same previously described treatment. Crossbred yearling heifers (n=261; 351±23 kg initial BW) were blocked by weight into heavy and light groups and randomly assigned to experimental pens containing 10 or 11 heifers each. In study 1, no interactions between levels of Cu and Linpro were observed. Copper concentration did not affect IVDMD (P>0.2) but increased (P<0.05) by 1.2% when Linpro was included. Final pH was not effected by added Cu (P>0.05), but pH increased when Linpro was added (P<0.05). Total VFA were greater in high-Cu treatments (P=0.038) and molar proportions were not affected (P>0.34). Linpro had no effect on total VFA (P=0.46) and molar proportions of propionate and isobutyrate increased whereas acetate and the acetate:propionate ratio decreased (P<0.01). Linpro increased the production of H2S (30% higher; P=0.05), and Cu inclusion slightly increased CO2 proportion (64.06 vs. 67.58% for Linpro vs. Cu treatments, respectively). In study 2, there were no interactions between levels of Linpro and supplemental Cu except for plasma n-6:n-3 ratio (P<0.01). Final BW were similar for cattle fed 0 and 10% Linpro (581 vs. 588 kg; P>0.20), but cattle fed diets with Linpro consumed less feed (14.08 vs. 13.59 kg/d; P<0.05) and were therefore more efficient (0.129 vs. 0.137 for 0 vs. 10% Linpro, respectively; P<0.01). Carcass traits were not affected by treatment. Feeding elevated levels of Cu did not appreciably alter PUFA proportions in plasma and LM. Plasma and LM concentrations of omega-3 fatty acids, including C18:3, C20:5, and C22:5, were greater for heifers fed Linpro (P<0.05). Increasing dietary Cu was not effective as a strategy for decreasing ruminal biohydrogenation and subsequent tissue deposition of PUFA.

Evaluations of hydrologic risk factors for canine leptospirosis: 94 cases (2002-2009).

Hydrologic and soil-hydrologic variables were evaluated retrospectively as potential risk factors for canine leptospirosis in Kansas and Nebraska using Geographic Information Systems (GIS). The sample included 94 positive and 185 negative dogs for leptospirosis predominantly based on PCR test for leptospires in urine. Hydrologic variables for the region were derived from National Hydrographic Dataset, National Flood Hazard Layer, National Wetlands Inventory; and soil-hydrologic variables from Soil Survey Geographic Database around geocoded addresses of case/control locations. Multivariable logistic models were used to determine association between hydrologic and soil-hydrologic variables and test status. Distance from water features (OR=0.82; 95% CI=0.79, 0.86), hydrologic density (OR=2.80; 95% CI=1.58, 4.96) and frequently flooded areas (OR=4.05; 95% CI=2.17, 7.55) within 2500 m surrounding case/control locations were significant risk factors for canine leptospirosis. Vaccination for dogs that live closer to water features, landscapes dominated by water features and frequent floods should be considered for leptospirosis prevention.

Neighborhood-level socioeconomic and urban land use risk factors of canine leptospirosis: 94 cases (2002-2009).

Associations of housing, population, and agriculture census variables, and presence near public places were retrospectively evaluated as potential risk factors for canine leptospirosis using Geographic Information Systems (GIS). The sample population included 94 dogs positive for leptospirosis based on a positive polymerase chain reaction test for leptospires on urine, isolation of leptospires on urine culture, a single reciprocal serum titer of 12,800 or greater, or a four-fold rise in reciprocal serum titers over a 2-4 week period; and 185 dogs negative for leptospirosis based on a negative polymerase chain reaction test and reciprocal serum titers less than 400. Multivariable logistic regressions revealed different risk factors among different census units; however, houses lacking complete plumbing facilities [OR=2.80, 95% C.I.=1.82, 4.32 (census unit, block group); OR=1.36, 95% C.I.=1.28, 1.45 (census tract); OR=3.02, 95% C.I.=2.60, 3.52 (county)]; and poverty status by age (18-64) [OR=2.04, 95% C.I.=1.74, 2.39 (block group); OR=1.53, 95% C.I.=1.41, 1.67 (census tract); and OR=1.62, 95% C.I.=1.50, 1.76 (county)] were consistent risk factors for all census units. Living within 2500 m of a university/college and parks/forests were also significantly associated with leptospirosis status in dogs. Dogs that live under these circumstances are at higher risk for leptospirosis and pet owners should consider vaccination.

Effects of mineral-supplement delivery system on frequency, duration, and timing of supplement use by beef cows grazing topographically rugged, native rangeland in the Kansas Flint Hills.

The effects of mineral-supplement delivery system on patterns of supplement use by grazing beef cows were measured in 2 studies. Study 1 was conducted on 4 pastures grazed by pregnant, mature beef cows (BW = 562 ± 38 kg) from February to May. Study 2 was conducted on 4 pastures grazed by lactating beef cows (BW = 579 ± 54 kg) and their calves from May to September. Treatments were mineral delivered in salt-based, granular form (salty) or mineral provided in a low-protein, cooked, molasses-based block (sweet); both were fed ad libitum. The salty supplement was supplied to cattle via a covered mineral feeder; the sweet supplement was supplied via an open-topped barrel. Both salty and sweet supplements were deployed in each pasture. No additional salt was supplied to cattle. Forage use in the vicinity of each supplement-deployment site and the frequency and duration of herd visits to each supplement-deployment site were measured during four 14-d periods during study 1 and seven 14-d periods during study 2. Supplements were moved to new locations within pastures at the beginning of each period. Consumption of the sweet supplement was greater than salty during each data-collection period in study 1; however, relative differences in consumption diminished over time (treatment × time, P = 0.03). In study 2, sweet consumption was greater than salty in periods 1, 6, and 7 but was not different from salty during periods 2, 3, 4, and 5 (treatment × time, P < 0.01). Increased consumption of the sweet supplement in study 1 translated to greater frequency of herd visits to supplement-deployment sites compared with the salty sites (2.82 vs. 2.47 herd visits/d; P = 0.02) and longer herd visits to supplement-deployment sites compared with the salty sites (125.7 vs. 54.9 min/herd visit; P < 0.01). The frequency of herd visits to mineral feeding sites in study 2 was similar (P > 0.10) between treatments for periods 1 through 6; however, herds visited the sweet sites more often than salty during period 7 (P < 0.01). Herd visits to the sweet sites were longer than those to the salty sites in study 2 (83.8 vs. 51.4 min/herd visit; P < 0.01). Forage disappearance within 100 m of supplement-deployment sites was not influenced (P ≥ 0.54) by treatment in either study. Results were interpreted to suggest that the sweet supplement influenced the location of grazing cattle more strongly than the salty supplement and may be more effective for luring cattle into specific areas of pasture during the winter, spring, and early fall but not during summer.

Effects of distillers grains with high sulfur concentration on ruminal fermentation and digestibility of finishing diets.

Twelve ruminally cannulated crossbred Angus steers were used to evaluate ruminal fermentation characteristics and diet digestibility when 30% (DM) corn dried distillers grains with solubles (DDGS) containing 0.42 or 0.65% (DM) of dietary S was incorporated into finishing diets based on steam-flaked corn (SFC) or dry-rolled corn (DRC). The study was a replicated, balanced randomized incomplete block design with a 2 × 2 factorial arrangement of treatments. Factors consisted of dietary S concentration (0.42 and 0.65% of DM; 0.42S and 0.65S, respectively) and grain processing method (SFC or DRC). The 0.65S concentration was achieved by adding H(2)SO(4) to DDGS before mixing rations. Steers were assigned randomly to diets and individual, slatted-floor pens, and fed once daily for ad libitum intake. Two 15-d experimental periods were used, each consisting of a 12-d diet adaptation phase and a 3-d sample collection phase. Samples were collected at 2-h intervals postfeeding during the collection phase. Ruminal pH was measured immediately after sampling, and concentrations of ruminal ammonia and VFA were determined. Fecal samples were composited by steer within period and used to determine apparent total tract digestibilities of DM, OM, NDF, CP, starch, and ether extract. Feeding 0.65S tended (P = 0.08) to decrease DMI but resulted in greater apparent total tract digestibilities of DM (P = 0.04) and ether extract (P = 0.03). Ruminal pH increased (P < 0.05) in steers fed 0.65S diets, which may be attributable, in part, to decreased (P = 0.05) VFA concentrations and greater (P < 0.01) ruminal ammonia concentrations when 0.65S was fed, compared with feeding 0.42S. These effects were more exaggerated in steers fed DRC (interaction, P < 0.01), compared with steers fed SFC. Steers fed DRC-0.65S had greater (P < 0.01) acetate concentration than steers fed DRC-0.42S, but acetate concentration was not affected by S concentration when SFC was fed. Propionate concentration was decreased (P < 0.01) in steers fed SFC-0.65S compared with steers fed SFC-0.42S, but dietary S concentration had no effect on propionate concentration when DRC was fed. Butyrate concentration was less (P < 0.01) in steers fed 0.65S diets than in steers fed 0.42S. Lactate concentrations tended (P = 0.06) to decrease in steers fed 0.65S diets. Feeding DDGS with increased S concentration may decrease feed intake and ruminal VFA concentration but increase ruminal ammonia concentration.

Evaluation of sulfur content of dried distillers grains with solubles in finishing diets based on steam-flaked corn or dry-rolled corn.

Crossbred yearling steers (n=80; 406 ± 2.7 kg of BW) were used to evaluate the effects of S concentration in dried distillers grains with solubles (DDGS) on growth performance, carcass characteristics, and ruminal concentrations of CH(4) and H(2)S in finishing steers fed diets based on steam-flaked corn (SFC) or dry-rolled corn (DRC) and containing 30% DDGS (DM basis) with moderate S (0.42% S, MS) or high S (0.65% S, HS). Treatments consisted of SFC diets containing MS (SFC-MS), SFC diets containing HS (SFC-HS), DRC diets containing MS (DRC-MS), or DRC diets containing HS (DRC-HS). High S was achieved by adding H(2)SO(4) to DDGS. Ruminal gas samples were analyzed for concentrations of H(2)S and CH(4). Steers were fed once daily in quantities that resulted in traces of residual feed in the bunk the following day for 140 d. No interactions (P ≥ 0.15) between dietary S concentration and grain processing were observed with respect to growth performance or carcass characteristics. Steers fed HS diets had 8.9% less DMI (P < 0.001) and 12.9% less ADG (P=0.006) than steers fed diets with MS, but S concentration had no effect on G:F (P=0.25). Cattle fed HS yielded 4.3% lighter HCW (P = 0.006) and had 16.2% less KPH (P=0.009) than steers fed MS. Steers fed HS had decreased (P=0.04) yield grades compared with steers fed MS. No differences were observed among treatments with respect to dressing percentage, liver abscesses, 12th-rib fat thickness, LM area, or USDA quality grades (P ≥ 0.18). Steers fed SFC had less DMI (P < 0.001) than steers fed DRC. Grain processing had no effect (P > 0.05) on G:F or carcass characteristics. Cattle fed HS had greater (P < 0.001) ruminal concentrations of H(2)S than cattle fed MS. Hydrogen sulfide concentration was inversely related (P ≤ 0.01) to ADG (r=-0.58) and DMI (r=-0.67) in cattle fed SFC, and to DMI (r=-0.40) in cattle fed DRC. Feeding DDGS that are high in dietary S may decrease the DMI of beef steers and compromise the growth performance and carcass characteristics of feedlot cattle.

Evaluation of dried distillers grains and roughage source in steam-flaked corn finishing diets.

Two studies were conducted to evaluate effects of dried distillers grains with solubles (DDGS) and alfalfa hay (AH) or corn silage (CS) on feedlot performance, carcass characteristics, ruminal fermentation, and diet digestibility in cattle fed steam-flaked corn (SFC) diets. In trial 1, crossbred heifers (n = 358; BW = 353 +/- 13 kg) were used in a finishing trial to evaluate interactions between corn-DDGS and roughage source (AH or CS) in terms of impact on feedlot performance and carcass characteristics. Experimental diets (DM basis) consisted of SFC and 11% CS without DDGS (SFC-CS), SFC and 11% CS with 25% DDGS (DDGS-CS), SFC and 6% AH without DDGS (SFC-AH), and SFC with 25% DDGS and 6% AH (DDGS-AH). Heifers were fed for ad libitum intake once daily for 97 d. Results indicated no interaction between DDGS and roughage source with respect to animal performance. Feeding DDGS did not affect ADG (P = 0.19), DMI (P = 0.14), or feed conversion (P = 0.67). Heifers fed CS had greater DMI than those fed AH (P = 0.05), but ADG (P = 0.56) and G:F (P = 0.63) were not different. There were no differences among treatments with respect to HCW, dressing percentage, subcutaneous fat thickness, quality grades, or yield grades (P > 0.20). Cattle fed CS tended (P = 0.10) to have greater marbling scores than those fed AH. There was an interaction (P = 0.02) between roughage and DDGS with respect to incidence of liver abscess. The greatest incidence was observed in cattle fed diets without DDGS when CS was fed, and the least was observed in cattle fed diets without DDGS when AH was used. In the second trial, ruminal fermentation characteristics and diet digestibility were examined in 12 cannulated Holstein steers fed similar diets to those fed in the finishing trial. Ruminal pH for all treatments was below 5.8 for 14 h after feeding. Acetate:propionate ratios were less (P = 0.02) in steers fed 25% DDGS but had greater (P = 0.02) ruminal lactate concentrations compared with cattle fed 0% DDGS. Feeding 25% DDGS decreased (P < 0.01) ruminal ammonia concentrations, and digestion of DM and OM was less (P < 0.01) compared with diets without DDGS. The decrease in digestibility was largely attributable to decreases in digestion of CP (P = 0.03) and NDF (P < 0.01). Feeding strategies aimed at increasing ruminal pH and ruminally available protein may improve digestion of DDGS in steam-flaked corn-based finishing diets.

Pregnancy outcome after insemination of frozen-thawed bovine semen packaged in two straw sizes: a meta-analysis.

The 0.25-mL French straw has been thoroughly studied and compared with the 0.5-mL French straw for about 40 yr. The 0.25-mL straw has some distinct advantages over the 0.5-mL straw in terms of storage efficiency and extender usage. The 0.25-mL straw is more sensitive to temperature change, which may be an advantage in some freezing systems with a slow freezing rate, but provides no advantage when the freezing rate is accelerated to optimize freezing in 0.5-mL straws. Disadvantages of the 0.25-mL straw include increased sensitivity to post-thaw temperature change, slightly more difficult handling, and inferior readability. Fertility of cattle inseminated with extended semen packaged in 0.25-mL straws assessed in 13 studies (>770,000 inseminations) had a weighted advantage of 0.9% (0.7% unweighted advantage) compared with semen packaged in 0.5-mL straws. In 2 studies in which palpated conception rates were obtained, the weighted advantage of the 0.25-mL versus the 0.5-mL straw was 0.2% (0.4% unweighted advantage). Paired t-tests did not detect a significant difference in pregnancy outcome between straw sizes. Logistic regression of all 15 studies (>780,000 inseminations) detected large variation among studies and tended to detect a small advantage for the 0.25-mL straw. Meta-analyses applied to fixed- or random-effect models of all 15 studies indicated the average odds of having a greater pregnancy outcome with the 0.25-mL straw were either 3 or 4% greater. Based on these odds ratios, the expected proportion of difference in pregnancy outcome translated into a difference of 0.74%. These small differences in pregnancy outcomes do not provide compelling evidence that a transition from 0.50- to 0.25-mL straws in the United States is warranted, especially given the added negative aspects of semen handling and the greater potential for technician x straw type interactions among herdsman inseminators.

Effects of increasing levels of dried corn distillers grains with solubles on growth performance, carcass characteristics, and meat quality of yearling heifers.

Three hundred forty-seven crossbred heifers (330 +/- 11 kg initial BW) were used in a randomized complete block study to identify the optimal level of dried corn distillers grains with solubles (DGS) in flaked corn finishing diets. Fifty-four pens were used, with 9 pens per treatment and 6 to 7 heifers per pen. Finishing diets were steam-flaked corn-based and were fed once daily for 148 d. Dietary treatments consisted of 6 levels of DGS (0, 15, 30, 45, 60, and 75%, DM basis). Dry matter intake, ADG, and final BW responded quadratically (P < or = 0.03) to increasing levels of DGS and were maximized at 15% DGS. However, G:F decreased linearly (P = 0.01) as level of DGS increased. Longissimus muscle areas were not different (P > or = 0.27), whereas 12th-rib fat thicknesses decreased linearly (P = 0.05) for heifers fed increasing levels of DGS. Marbling score and USDA yield grades were not different (P > or = 0.06) for heifers fed different levels of DGS. Number of carcasses grading USDA Prime or Choice were not different (P > or = 0.07), whereas number of carcasses grading USDA Select increased (P = 0.02; linear) as dietary level of DGS increased from 0 to 75%. Myofibrillar and overall tenderness increased linearly (P = 0.01) as dietary level of DGS increased from 0 to 75%. Juiciness, off-flavor intensity, and thiobarbituric acid reactive substances were not different (P > or = 0.16) among treatments. Redness of steaks (i.e., a*) was not different (P > or = 0.13) for steaks collected from heifers fed different levels of DGS as evidenced by similar instrumental color measurements after d 0, 3, and 5 of display. However, on d 7, steak color was less red (P = 0.04) and had more metmyoglobin. Concentration of linoleic acid (18:2n-6cis), total n-6 fatty acids, and total PUFA linearly increased (P = 0.01) with increasing levels of DGS.

Optimizing use of distillers grains in finishing diets containing steam-flaked corn.

Two hundred ninety-nine crossbred yearling steers (363 +/- 15 kg initial BW) were fed for an average of 114 d in a finishing study comparing 7 diets in which steam-flaked corn was used as the principal energy source. Forty-nine pens were used in this study with 7 BW blocks, 7 pens per treatment, and 5 to 7 steers per pen. A control diet with no distillers grains with solubles (DGS) was compared with 6 diets containing 15% DGS (DM basis). The diets contained wet sorghum DGS with 0 or 6% alfalfa hay, dried sorghum DGS with 0 or 6% alfalfa hay, wet corn DGS with 6% alfalfa hay, or dried corn DGS with 6% alfalfa hay. Apparent total tract digestibilities were calculated by total collection of fecal material from the concrete-surfaced pens over a 72-h period. Dry matter intake, ADG, G:F, and carcass characteristics were similar (P > or = 0.18) for steers fed finishing diets with or without 15% DGS. However, apparent total tract digestibilities of DM and OM were 2.8% less (P < or = 0.03) for finishing diets containing 15% DGS (DM basis). Dry matter intake, ADG, G:F, apparent total tract digestibility, and carcass characteristics were not different (P > or = 0.09) for steers fed finishing diets containing sorghum or corn DGS. Dry matter intake, ADG, G:F, apparent total tract digestibility, and carcass characteristics also were not different (P > or = 0.10) for steers fed finishing diets containing wet or dried DGS. Steers fed sorghum DGS with 6% hay consumed more DM (P < 0.01) and gained more BW (P < 0.01) than steers fed diets without hay, but G:F were not different (P > 0.78). Sorghum DGS diets containing alfalfa hay were 4% less (P = 0.01) digestible than sorghum DGS diets containing no hay. Carcasses of steers fed sorghum DGS diets without hay were lighter, leaner, and had decreased USDA yield grades (P = 0.01) compared with steers fed sorghum DGS diets containing hay. Feeding moderate levels (i.e., 15%, DM basis) of DGS resulted in growth performance and carcass characteristics similar to those of cattle fed no DGS. In addition, sorghum- and corn-based DGS had similar feeding values, and wet (approximately 31% DM) and dried (approximately 91% DM) DGS also had similar feeding values. Complete removal of alfalfa hay in diets containing DGS improved diet digestibility but reduced growth performance and carcass finish.

Effects of implanting and feeding zilpaterol hydrochloride on performance, carcass characteristics, and subprimal beef yields of fed cows.

Sixty crossbred cull cows were used to determine the combined effects of a trenbolone acetate-estradiol implant and feeding zilpaterol hydrochloride on performance, carcass characteristics, and subprimal yields of mature cows fed for 70 d. Cows were assigned to 1 of 5 treatments: 1) grazing native grass pasture (G); 2) concentrate-fed (C) a grain sorghum-sorghum silage diet; 3) concentrate-fed and implanted (CI) with Revalor-200 (trenbolone acetate-estradiol); 4) concentrate-fed and fed Zilmax (zilpaterol hydrochloride) beginning on d 38 of the feeding period (CZ); and 5) concentrate-fed, implanted, and fed Zilmax beginning on d 38 (CIZ). The concentrate diet consisted primarily of ground grain sorghum and sorghum silage. During the last 34 d of the feeding trial, concentrate-fed (C, CI, CZ, and CIZ) cows had greater (P < 0.05) gains than G cows. Hot carcass weights and dressing percentages were greater (P < 0.05) for the concentrate-fed cows than for G cows. Longissimus muscle area was largest (P < 0.05) for CIZ cows, whereas subprimal weights from the chuck were heavier (P < 0.05) from CIZ cows than C and G cows, and carcasses from CI and CZ cows had heavier (P < 0.05) chuck subprimal weights than G cows. Rib and round subprimal weights were heavier (P < 0.05) for concentrate-fed cows compared with G cows. In addition, carcasses from CIZ cows had heavier (P < 0.05) total subprimal weights, and total subprimals were a greater percentage of their initial BW than C cows. Rib cut-out and total soft tissue weights from the 9-10-11th rib were less (P < 0.05) for G cows than concentrate-fed cows. Feeding cull cows a concentrate diet increased carcass weight, dressing percentage, and subprimal yields compared with feeding cows a grass-based pasture diet, and the combination of a trenbolone acetate-estradiol implant and feeding zilpaterol hydrochloride can maximize trimmed beef yields from cull cows fed a high-concentrate diet.

Effects of feeding L-carnitine to gilts through day 70 of gestation on litter traits and the expression of insulin-like growth factor system components and L-carnitine concentration in foetal tissues.

We investigated the influence of supplemental L-carnitine on foetal blood metabolites, litter characteristics, L-carnitine concentration in skeletal muscle and insulin-like growth factor (IGF) axis components in foetal hepatic and skeletal muscle tissues at day 40, 55 and 70 of gestating gilts. A total of 59 gilts (body weight = 137.7 kg) received a constant feed allowance of 1.75 kg/day and a top-dress containing either 0 or 50 ppm of L-carnitine starting on the first day of breeding through the allotted gestation length. Foetuses from the gilts fed diets with L-carnitine tended to be heavier (p = 0.06) and the circulating IGF-II tended to be lower (p = 0.09) at day 70, compared with the foetuses from the control gilts. Insulin-like growth factor-I messenger RNA (mRNA) was lower (p = 0.05) in hepatic tissue in the foetuses collected from gilts fed L-carnitine. Free and total carnitine concentration increased (p < 0.05) in the skeletal muscle from the foetuses collected from gilts fed supplemental L-carnitine. This study showed that L-carnitine had beneficial effects on the average foetal weight at day 70 of gestation, associated with changes in the foetal IGF system.

The effects of feeding flaxseed during the receiving period on morbidity, mortality, performance, and carcass characteristics of heifers.

Two experiments were conducted at the Kansas State University Beef Cattle Research Center to determine the effects of feeding ground flaxseed (flax) during the receiving period on the growth, health, and subsequent finishing performance of heifers. Crossbred heifers (Exp. 1: n = 363, 214 +/- 1 kg of initial BW; Exp. 2: n = 377, 222 +/- 1 kg of initial BW) were purchased during January and April of 2006. Heifers were fed receiving rations based on steam-flaked corn with 0, 2, 4, or 6% ground flax (DM basis) for 56 d. Following the receiving period, cattle in Exp. 1 and 2 were fed steam-flaked corn-based diets for 150 and 147 d, respectively, and then slaughtered. Heifers were implanted 91 and 109 d before slaughter for Exp. 1 and 2, respectively. In Exp. 1, DMI during the receiving period tended to increase linearly (P = 0.09) with increasing flax in the diet. Average daily gain was 1.46, 1.56, 1.58, and 1.61 kg for heifers fed 0, 2, 4, and 6% flax, respectively (linear, P = 0.03). Final BW in Exp. 1 after the finishing period was increased (linear, P = 0.04) with increasing inclusion of flax in the receiving diets. In Exp. 2, growth performance and mortality during the receiving period were not different among treatments (P > 0.12). During the receiving period in Exp. 2, incidence of the first respiratory treatment tended to be greatest (P = 0.09) for heifers fed 4% flax. During the finishing period, DMI were 8.4, 8.4, 8.0, and 8.1 kg/d for 0, 2, 4, and 6% flax, respectively (linear, P = 0.05). In Exp. 2, LM areas were greatest (quadratic, P = 0.04) for cattle fed 2% flax at receiving. In general, feeding flax during the receiving period may have the potential to improve growth performance; however, performance between experiments was variable, and many factors excluding flax feeding may have contributed to this response.

Efficacy of monensin and tylosin in finishing diets based on steam-flaked corn with and without corn wet distillers grains with solubles.

Three hundred seventy-one crossbred-yearling heifers (299 +/- 9 kg initial BW) were obtained from a common source and used in a randomized complete-block designed finishing study. A 2 x 3 factorial arrangement of treatments was used with one factor being diet: based on steam-flaked corn finishing diet (SFC) or SFC plus 25% (dry basis) corn wet distillers grains with solubles (WDGS). The second factor was feed additives: no added antibiotics (NONE), 300 mg of monensin daily (MONENSIN), or 300 mg of monensin + 90 mg of tylosin daily (MON+TYL). Main effect of diet resulted in no difference in DMI (P = 0.34). Heifers fed SFC gained 9% faster (P = 0.01) and were 7% more efficient (P = 0.01) than heifers fed WDGS. In addition, heifers fed SFC had 3% heavier (P = 0.01) HCW; 1% greater (P = 0.01) dress yield; and had 3% larger (P = 0.05) LM area. Marbling score and carcasses that graded USDA Choice or better were both greater (P /= 0.12) among feed additive treatments. Kidney, pelvic, and heart fat and s.c. fat thickness at the 12th rib were also not different (P >/= 0.55) for main effects of diet and feed additive. There was a tendency (P = 0.09) for a diet x feed additive interaction for the most severe (A+) liver abscesses. Heifers fed NONE yielded the greatest percentage (16%) of A+ livers in the SFC treatment, whereas heifers fed MON+TYL yielded the greatest percentage (10%) in the WDGS treatment. Including wet distillers grains with solubles in diets based on steam-flaked corn decreased finishing heifer performance, HCW, and marbling. Tylosin addition tended to decrease severity of liver abscesses in diets containing SFC, but not in diets containing WDGS. These data indicate that monensin and tylosin may not be as effective when used in steam-flaked corn diets with 25% WDGS.

Source of dietary lipid may modify the immune response in stressed feeder cattle.

Five studies were conducted to evaluate the effects of lipid source on performance and health of stressed feeder cattle. A total of 332 heifers (195 +/- 2.37 kg initial BW) in trial 1 and 336 heifers (206 +/- 1.70 kg initial BW) in trial 2 were fed diets containing ground flaxseed (FLAX), rolled full-fat soybeans (SOY), or tallow (TAL) at 13, 20, or 4%, respectively (DM basis). All diets were formulated to be isonitrogenous and isocaloric. The ADG and G:F for the first 7 d and for the entire feeding period were greater (P < 0.05) for TAL and FLAX than for SOY. Percentage of animals treated and retreated for bovine respiratory disease did not differ among dietary treatments. The FLAX treatment increased (P < 0.05) total n-3 PUFA concentrations in the plasma, whereas SOY increased (P < 0.05) plasma concentrations of total n-6 PUFA. In trial 3, 18 steers were individually fed diets containing TAL and 18 steers were fed a diet containing SOY (20% of DM). In trials 4 and 5, 18 steers were individually fed diets containing TAL and 18 steers were fed diets containing FLAX (12.9% of DM). On d 14 and 17 of study 3, 4, and 5, 16 steers from each dietary treatment were injected i.v. with Escherichia coli O55:B5 lipopolysaccharide (LPS), and 2 steers from each diet were injected with saline. Rectal temperatures after LPS challenge were lower (P < 0.05) for SOY and FLAX than for TAL, and plasma TNF was greater (P < 0.05) for SOY than for TAL. Serum haptoglobin and blood fibrinogen increased and white blood cell count decreased in response to LPS, but none of these variables was affected by treatment. Although this research failed to measure an effect of lipid source on feedlot morbidity or mortality, these studies indicate that altering the source and type of dietary fatty acids may modify the immune response in stressed feeder cattle and that performance may be hindered by feeding full-fat soybeans to receiving cattle.

Effects of steroidal implantation and ractopamine-HCl on nitrogen retention, blood metabolites and skeletal muscle gene expression in Holstein steers.

Six Holstein steers (231 +/- 17 kg) housed in metabolism crates were used in a randomized complete block design with three blocks of two steers based on previous serum insulin-like growth factor (IGF)-I concentrations. One of the two steers in each block was implanted with 120 mg trenbolone acetate and 24 mg oestradiol-17beta on day 0. None of the steers was fed ractopamine-HCl in the initial 28 days, and then all steers were fed 200 mg of ractopamine-HCl per steer daily from day 28 until the end of the trial. Steers were fed a corn-based diet (62% rolled corn, 20% expeller soya bean meal and 15% alfalfa hay) twice daily with an average dry matter intake of 4.8 kg/day. Blood and M. longissimus biopsy samples were collected prior to implantation and on days 14, 28, 42 and 56. There was an implant x ractopamine interaction for retained nitrogen (p < 0.05); ractopamine feeding led to only small improvements in nitrogen retention for implanted steers (45.9 g/day vs. 44.5 g/day), whereas ractopamine led to larger increases in nitrogen retention for non-implanted steers (39.0 g/day vs. 30.4 g/day). Implantation increased (p < 0.05) and ractopamine tended to decrease (p = 0.06) serum IGF-I concentrations. Implantation tended to increase (p = 0.16) and ractopamine decreased (p < 0.05) mRNA expression of IGF-I in the M. longissimus. Ractopamine decreased mRNA expression of beta(1)- and beta(2)-receptors in M. longissimus (p

Growth characteristics, blood metabolites, and insulin-like growth factor system components in maternal tissues of gilts fed L-carnitine through day seventy of gestation.

A total of 59 gilts (BW = 137.7 kg) from 3 breeding groups were used to assess the effects of feeding l-carnitine during gestation on gilt growth characteristics, blood metabolites, and uterine and chorioallantoic expression of IGF axis components at d 40, 55, and 70 of gestation. Experimental treatments were arranged in a 2 x 3 factorial, with main effects of added l-carnitine (0 or 50 ppm) and day after initial breeding (d 40, 55, or 70 of gestation). All gilts received a constant feed allowance of 1.75 kg/d and a top-dress containing 0 or 50 ppm of l-carnitine beginning on the first day of breeding through the assigned day of gestation. No dietary treatment differences were observed for gilt BW, backfat, or estimated protein or fat mass at any day of gestation. No differences were observed in circulating total and free carnitine at breeding, but concentrations increased (P < 0.01) as day of gestation increased for gilts fed diets containing l-carnitine compared with those fed the control diet. Maternal IGF-I concentration decreased (P < 0.01) from d 0 to 70 for all gilts, with no differences between treatments. Insulin-like growth factor binding protein-3 mRNA (P = 0.05) and IGFBP-5 mRNA (P = 0.01) increased in the endometrium of gilts supplemented with l-carnitine. These data demonstrate that l-carnitine supplementation and day of gestation alter the expression of the IGF axis by changing the expression of IGFBP at the fetal-maternal interface in swine. These changes in the IGF axis at the fetal maternal interface may aid in determining the reasons for the effects of l-carnitine on reproductive traits.

Effects of melengestrol acetate on the inflammatory response in heifers challenged with Mannheimia haemolytica.

Previous research from our laboratory has indicated that melengestrol acetate (MGA) added to the diet during the first 35 d after arrival in the feedlot improves growth rates and tends to reduce chronic respiratory disease in heifers naturally challenged with bovine respiratory disease. The current study was conducted to provide further insight into the possible immunomodulatory effects of MGA. Crossbred heifers (n = 48; 232 +/- 5.5 kg of BW) were used in a randomized complete block design to determine the effects of MGA on lung pathology and markers of inflammation after Mannheimia haemolytica challenge. On d 0, cattle were blocked by BW and randomly assigned, within block, to diets (54% concentrate) that provided 0 or 0.5 mg of MGA per heifer daily for the duration of the experiment. Inoculum containing from 1.3 x 10(9) to 1.7 x 10(9) cfu of M. haemolytica (20 mL) was instilled at the bifurcation of the trachea on d 14. Blood samples were collected, clinical observations were made, and rectal temperatures were recorded for each animal at 0, 12, 24, 48, 72, 96, 120, and 138 h after inoculation. Heifers fed MGA had greater circulating concentrations of eosinophils and postchallenge concentrations of segmented neutrophils and white blood cells (P < 0.01) than controls, as well as elevated plasma protein, serum haptoglobin, and fibrinogen after M. haemolytica challenge (P < 0.01). Heifers fed MGA had lower plasma glucose (P < 0.01), greater plasma urea N (P = 0.02), and elevated respiratory indices (P < 0.01) compared with controls. Necropsies performed on d 6 after inoculation suggested that M. haemolytica challenge was relatively mild, because lesions were confined to a small portion of the lungs. On a 0 to 100 scale, average lung lesion scores were 3 and 1 for MGA-fed and control groups, respectively (P < 0.06). Heifers fed MGA before mild M. haemolytica challenge were more susceptible to infection, as evidenced by a greater number of heifers fed MGA exhibiting pulmonary lesions 138 h after inoculation than controls (14 out of 23 vs. 6 out of 24 for MGA and controls, respectively; P < 0.02).

Effects of potassium lactate, sodium chloride, sodium tripolyphosphate, and sodium acetate on colour, colour stability, and oxidative properties of injection-enhanced beef rib steaks.

This study determined the effects of potassium lactate (KL), sodium chloride, sodium tripolyphosphate, and sodium acetate on colour, colour stability, and oxidative properties of injection-enhanced beef rib steaks. Enhancement solutions (8.5% pump) contained combinations of KL (0% or 1.5%), sodium chloride (0.3% or 0.6%), sodium tripolyphosphate (0% or 0.3%), and sodium acetate (0% or 0.1%). Steaks were packaged in a high-oxygen modified atmosphere (80% O(2)/20% CO(2)). Steaks with KL or KL and sodium acetate were darker but more colour stable (P<0.05) than control steaks. Steaks had less glossy surfaces when they contained acetate (P<0.05) and KL (P<0.11). Increasing sodium chloride content resulted in darker, less colour-stable steaks (P<0.05). Removing phosphate had little impact on colour (P>0.05). Both KL and sodium acetate improved visual appearance of injection-enhanced beef rib steaks, whereas the greater salt level were detrimental.