Changing paradigm of sacral neuromodulation and external anal sphincter repair for faecal incontinence in specialist centres.

AIM: The aim of this study was to determine whether the paradigm of surgical intervention for faecal incontinence (FI) has changed between 2000 and 2013. METHOD: This was a multi-centre retrospective study of patients who had undergone either sacral neuromodulation (SNM) or delayed sphincter repair or sphincteroplasty (SR) as a primary surgical intervention for FI in five centres in Europe and one in the United States. The flow of patients according to the intervention, sustainability of the treatment at a minimum follow-up of 5 years, complications and requirement for further interventions were recorded. RESULTS: A total of 461 patients (median age 56 years, range 24-90 years, 41 men) had either SNM or SR as an index operation during the study period [SNM 284 (61.6%), SR 177 (38.4%)]. Among SNM patients, there were 169 revisional operations (change of battery and/or lead, re-siting or removal). At the time of last follow-up 203 patients (71.4%) continued to use SNM. Among SR patients, 30 (16.9%) had complications, most notably wound infection (22, 12.4%). During follow-up 32 patients (18.1%) crossed over to SNM. Comparing two 4-year periods (2000-2003 and 2007-2010), the proportion of patients operated on who had a circumferential sphincter defect of less than 90° was 48 (68%) and 45 (46%), respectively (P = 0.03), while those who had SNM as the primary intervention increased from 29% to 89% (P < 0.05). CONCLUSION: The paradigm of surgical intervention for FI has changed with increasing use of SNM.

Synoptic assessment of coastal total alkalinity through community science.

Comprehensive sampling of the carbonate system in estuaries and coastal waters can be difficult and expensive because of the complex and heterogeneous nature of near-shore environments. We show that sample collection by community science programs is a viable strategy for expanding estuarine carbonate system monitoring and prioritizing regions for more targeted assessment. 'Shell Day' was a single-day regional water monitoring event coordinating coastal carbonate chemistry observations by 59 community science programs and seven research institutions in the northeastern United States, in which 410 total alkalinity (TA) samples from 86 stations were collected. Field replicates collected at both low and high tides had a mean standard deviation between replicates of 3.6 ± 0.3 µmol kg-1 (σ mean ± SE, n = 145) or 0.20 ± 0.02%. This level of precision demonstrates that with adequate protocols for sample collection, handling, storage, and analysis, community science programs are able to collect TA samples leading to high-quality analyses and data. Despite correlations between salinity, temperature, and TA observed at multiple spatial scales, empirical predictions of TA had relatively high root mean square error >48 µmol kg-1. Additionally, ten stations displayed tidal variability in TA that was not likely driven by low TA freshwater inputs. As such, TA cannot be predicted accurately from salinity using a single relationship across the northeastern US region, though predictions may be viable at more localized scales where consistent freshwater and seawater endmembers can be defined. There was a high degree of geographic heterogeneity in both mean and tidal variability in TA, and this single-day snapshot sampling identified three patterns driving variation in TA, with certain locations exhibiting increased risk of acidification. The success of Shell Day implies that similar community science based events could be conducted in other regions to not only expand understanding of the coastal carbonate system, but also provide a way to inventory monitoring assets, build partnerships with stakeholders, and expand education and outreach to a broader constituency.

Effects of dietary potato by-product and rumen-protected histidine on growth, carcass characteristics and quality attributes of beef.

We hypothesized that variable composition in finishing rations, more specifically; the proportion of potato-by-product (PBP) and rumen protected histidine (His) supplementation may influence growth and meat quality attributes. Two different diets were fed (1) finishing ration with corn and barley as grains (CB, n = 20) and (2) substitution of 10% corn, DM basis, with PBP (PBP, n = 20). Additionally, half of each dietary treatment received 50 g/hd/d rumen protected His (HS, n= 20) while the other half received no supplement (NS, n = 20). Inclusion of 10% PBP or HS did not affect growth or carcass traits. Color stability was analyzed using Hunter color values as well as AMSA visual appraisal in both longissimus thoracis (LT) and gluteus medius (GM) muscles. The LT, but not the GM, of CB steers was more color stable over a 9 d simulated retail display compared to those fed a PB diet. Steers receiving HS produced significantly (P < 0.05) more color stable LT and GM steaks.

Effect of preslaughter feeding and ractopamine hydrochloride supplementation on growth performance, carcass characteristics, and end product quality in market dairy cows.

An experiment was conducted in market dairy cows to determine the effect of feeding time and ractopamine hydrochloride (RAC) on growth performance, carcass characteristics, and end product quality. In 3 replicates, 9 Holstein cows per replicate (n = 27; 659 +/- 25.3 kg initial BW) culled from 3 dairies were randomly assigned to 3 treatments: 1) slaughter immediately (control), 2) feed for 90 d (NoR), or 3) feed for 90 d with RAC (312 mg.cow(-1).d(-1)) for the final 32 d (RAC). On d 0, NoR and RAC cows were placed in individual pens and fed a high concentrate diet (86% concentrate, DM basis) for 90 d before slaughter. All cows were subjectively scored for BCS and locomotion score on d 0, and NoR and RAC cows were evaluated again after 90 d. Individual DMI was recorded daily throughout the trial, and BW was collected every 14 d. Age and age x treatment did not affect (P > 0.05) any of the traits evaluated in this study. When cows fed for 90 d (NoR and RAC combined) were compared with nonfed controls, fed cows had greater (P < 0.001) final BCS, BW and HCW, lower (P < 0.001) final locomotion score, and greater (P < 0.03) dressing percentage, external fat thickness, and marbling score. Fed cows also tended to have more desirable yield grade (P = 0.08), ribeye area (P = 0.11), fat color (P = 0.09), lean maturity (P = 0.06), and quality grade (P = 0.09) compared with control cows. Warner-Bratzler shear force was not affected (P = 0.23) by feeding. However, a 12-member trained sensory panel revealed that fed cow carcasses had more desirable (P < 0.04) tenderness, juiciness, and overall acceptability than control cow carcasses. Flavor intensity also tended (P = 0.10) to be more desirable for fed vs. control cows. No difference (P > 0.10) in off-flavor was detected among treatments. Finally, there was no effect (P > 0.10) of RAC on growth performance, carcass characteristics, or end product quality. In conclusion, feeding a high concentrate diet for 90 d improved important live animal, carcass, and end product characteristics related to the quality and palatability of beef from market dairy cows; however, no effect of RAC supplementation was observed.

Effect of intake level and alfalfa substitution for grass hay on ruminal kinetics of fiber digestion and particle passage in beef cattle.

Two experiments were conducted to evaluate digestion kinetics of alfalfa (Medicago sativa L.) substitution for grass hay in beef cattle. In Exp. 1, forage combinations evaluated in situ consisted of 0% alfalfa-100% big bluestem (Andropogon gerardi Vitman), 25% alfalfa-75% big bluestem, 50% alfalfa-50% big bluestem, and 100% alfalfa-0% big bluestem. Nonlinear regression was used to determine the immediately soluble fraction A, the potentially degradable fraction B, the undegraded fraction C, and the disappearance rate of DM and NDF. Dry matter fraction A increased linearly (P = 0.03), and DM and NDF fraction B decreased linearly (P = 0.01) with increasing alfalfa substitution. Rate of DM and NDF disappearance increased linearly (P /= 0.23) on total tract apparent digestibility of all nutrients except CP. Steers fed orchardgrass plus alfalfa had 33% greater (P = 0.01) total tract apparent digestibility for CP than those fed orchardgrass alone. Lag time of DM and NDF disappearance was not affected (P >/= 0.20) by alfalfa supplementation or intake level. Rate of DM and NDF disappearance of orchardgrass was faster (P

Influence of endosperm vitreousness and kernel moisture at harvest on site and extent of digestion of high-moisture corn by feedlot steers.

Six ruminally and duodenally cannulated Angus-Jersey crossbred steers (450 kg of BW) were used in a 6 x 6 Latin square to evaluate the effect of kernel vitreousness and moisture on intake and digestibility of high-moisture corn. Arranged in a 2 x 3 factorial, diets included a floury (FLO) or a vitreous (VIT) endosperm corn hybrid harvested at 28.1% (DRY), 31.2% (MID), or 35.7% (WET) kernel moisture content. Diet DM consisted of 88.25% high-moisture corn, 6% chopped alfalfa hay, 2% corn gluten meal, 0.75% urea, and 3% supplement. Supplement was included to ensure that the diets contained a minimum (DM basis) of 0.6% Ca, 0.6% K, 0.2% S, 33 mg/kg of monensin, and 11 mg/kg of tylosin. Geometric mean diameter of lyophilized high-moisture corn tended to be less (P = 0.06) for VIT than for FLO, and the calculated particle surface area was 15.8% greater (P = 0.03). An interaction of vitreousness with the quadratic effect of moisture was noted (P < 0.001), such that fraction a and effective degradation for starch tended to be greater for the vitreous hybrid at the least and greatest moisture content but lower for the vitreous hybrid at the intermediate moisture content. Intake and ruminal disappearance of DM, OM, and starch were not influenced by vitreousness or moisture, with ruminal starch disappearance averaging 90.9%. Intestinal starch digestion measured as a percentage of starch entering the intestines averaged 91% and was greater (P < 0.05) for VIT than FLO corn. Averaged across moisture levels, total tract starch digestibility was greater (P < 0.003) for VIT than FLO. Compared with FLO kernels, VIT kernels appeared to be more brittle and therefore shattered more readily when rolled, particularly at the driest kernel moisture level. Furthermore, increased surface area of smaller particles may have been responsible for the greater starch utilization from VIT corn. In contrast with the results from other in situ and in vivo trials with dry-rolled corn grain, in which the starch from vitreous hybrids was less rapidly or completely digested, hybrids with more vitreous starch, when fed as high-moisture corn, had greater total tract starch digestibility, primarily due to greater postruminal starch digestion.

Effect of barley and its amylopectin content on ruminal fermentation and nitrogen utilization in lactating dairy cows.

The effect of type of grain (corn vs. barley) and amylopectin content of barley grain (normal vs. waxy) on ruminal fermentation, digestibility, and utilization of ruminal ammonia nitrogen for milk protein synthesis was studied in a replicated 3 x 3 Latin square design trial with 6 lactating dairy cows. The experimental treatments were (proportion of dietary dry matter): CORN, 40% corn grain, NBAR, 30% normal Baronesse barley:10% corn grain, and WBAR, 30% high-amylopectin (waxy) Baronesse barley:10% corn grain. All grains were steam-rolled and fed as part of a total mixed ration. The NBAR and WBAR diets resulted in increased ruminal ammonia concentrations compared with CORN (8.2, 7.4, and 5.6 mM, respectively), but other ruminal fermentation parameters were not affected. Ruminal digestibility of dietary nutrients and microbial protein synthesis in the rumen were also not affected by diet. Corn grain had greater in situ effective ruminal dry matter degradability (62.8%) than the barley grains (58.2 and 50.7%, respectively), and degradability of the normal barley starch was greater than that of the waxy barley (69.3 and 58.9%, respectively). A greater percentage of relative starch crystallinity was observed for the waxy compared with the normal barley grain. Total tract apparent digestibility of dry matter and organic matter were decreased by WBAR compared with CORN and NBAR. Total tract starch digestibility was greater and milk urea nitrogen content was lower for CORN compared with the 2 barley diets. In this study, the extent of processing of the grain component of the diet was most likely the factor that determined the diet responses. Minimal processing of barley grain (processing indexes of 79.2 to 87.9%) reduced its total tract digestibility of starch compared with steam-rolled corn (processing index of 58.8%). As a result of the increased ammonia concentration and reduced degradability of barley dry matter in the rumen, the utilization of ruminal ammonia nitrogen for microbial protein synthesis was decreased with the barley diets compared with the corn-based diet. In this study, waxy Baronesse barley was less degradable in the rumen and the total digestive tract than its normal counterpart. The most likely reasons for these effects were the differences in starch characteristics and chemical composition, and perhaps the different response to processing between the 2 barleys.

Residual feed intake of purebred Angus steers: effects on meat quality and palatability.

Relationships between residual feed intake (RFI) and other performance variables were determined using 54 purebred Angus steers. Individual feed intake and BW gain were recorded during a 70-d post-weaning period to calculate RFI. After the 70-d post-weaning test, steers were fed a finishing ration to a similar fat thickness (FT), transported to a commercial facility, and slaughtered. A subsample of carcasses (n = 32) was selected to examine the relationships among RFI, meat quality, and palatability. Steers were categorized into high (> 0.5 SD above the mean; n = 16), medium (mid; +/- 0.5 SD from the mean; n = 21), and low (< 0.5 SD below the mean; n = 17) RFI groups. No differences were detected in ADG, initial BW, and d 71 BW among the high, mid, and low RFI steers. Steers from the high RFI group had a greater DMI (P = 0.004) and feed conversion ratio (FCR; DMI:ADG; P = 0.002) compared with the low RFI steers. Residual feed intake was positively correlated with DMI (r = 0.54; P = 0.003) and FCR (r = 0.42; P = 0.002), but not with initial BW, d 71 BW, d 71 ultrasound FT, initial ultrasound LM area, d 71 ultrasound LM area, or ADG. The FCR was positively correlated with initial BW (r = 0.46; P = 0.0005), d 71 BW (r = 0.34; P = 0.01), and DMI (r = 0.40; P = 0.003) and was negatively correlated with ADG (r = -0.65; P = 0.001). There were no differences among RFI groups for HCW, LM area, FT, KPH, USDA yield grade, marbling score, or quality grade. Reflectance color b* scores of steaks from high RFI steers were greater (P = 0.02) than those from low RFI steers. There was no difference between high and low RFI groups for LM calpastatin activity. Warner-Bratzler shear force and sensory panel tenderness and flavor scores of steaks were similar across RFI groups. Steaks from high RFI steers had lower (P = 0.04) off-flavor scores than those from low RFI steers. Cook loss percentages were greater (P = 0.005) for steaks from low RFI steers than for those from mid RFI steers. These data support current views that RFI is independent of ADG, but is correlated with DMI and FCR. Importantly, the data also support the hypothesis that there is no relationship between RFI and beef quality in purebred Angus steers.

Effects of pasteurization of potato slurry by-product fed in corn-or barley-based beef finishing diets.

Pasteurization of vegetable by-products such as potato slurry (PS) before feeding may be necessary to prevent the spread of pathogens and beef carcass blemishes. We hypothesized that pasteurization would increase ruminal fermentability of PS starch. Four ruminally cannulated crossbred beef steers (initial BW = 432) were used in a 4 x 4 Latin square experiment with a 2 x 2 factorial arrangement of treatments to examine the main effects and interactions of pasteurization (54.4 degrees C for 2 h) of PS and grain type (GT; dry-rolled corn and barley) on ruminal and total tract digestion of beef finishing diets. Diets contained 7% alfalfa hay and 14% PS (DM basis) and were fed ad libitum three times daily. Corn-based diets had 71.7% corn, whereas barley-based diets had 60% barley and 11.7% corn. Pasteurization resulted in greater (P = 0.004) soluble, rapidly degradable starch (34.3 vs. 26.7% for pasteurized and nonpasteurized PS, respectively). Ruminal fluid pH was more acidic (P < 0.07) for corn-based diets than for barley-based diets (P = 0.07) at 0200 and 2100 (sample time x GT; P < 0.05). Ruminal fluid pH was more acidic (P = 0.06) at 1400 for corn-based diets containing pasteurized PS compared with other dietary treatments (sample time x pasteurization x GT; P = 0.04). Minimum and maximum ruminal pH were greater (P < 0.10) for barley-based diets than for corn-based diets. Ruminal fluid pH was < 6.0 for a greater (P = 0.04) proportion of the day for corn-based compared with barley-based diets. In vitro incubation measurements revealed that pasteurization of PS resulted in lower (P = 0.06) ruminal fluid ammonia N concentration. Ruminal fluid ammonia N concentration was lower (P = 0.11) for barley-based diets than for corn-based diets. Steers fed barley-based diets had greater (P = 0.02) DMI and lesser (P < 0.05) total tract digestibility of DM and ADF compared with steers fed corn diets. Pasteurization increased (P = 0.10) total tract starch digestibility. Results indicate pasteurization increased rapidly degradable starch, ruminal starch fermentability, and total tract starch digestibility of PS. Grain type interacted with pasteurization such that feeding corn-based diets containing pasteurized PS resulted in periodic reductions in ruminal pH. Feeding management may be more critical when feeding pasteurized PS in beef finishing diets.

Effect of diets containing linoleic acid- or oleic acid-rich oils on ruminal fermentation and nutrient digestibility, and performance and fatty acid composition of adipose and muscle tissues of finishing cattle.

Two trials were conducted to determine the effect of linoleic acid- or oleic acid-rich safflower oil on ruminal fermentation, nutrient digestion, feedlot performance, carcass characteristics, and fatty acid composition of adipose and muscle tissues of beef cattle. In both trials, cattle were fed a finishing diet based on barley grain, wheat silage, and alfalfa hay. Oils were fed at 5% of dietary DM. In a metabolism trial, four ruminally and duodenally cannulated Angus crossbred steers were subjected to linoleic acid-rich oil or oleic acid-rich oil in a crossover design with covariate periods (no oil supplementation). In a finishing trial, 16 individually fed Angus crossbred steers and heifers (eight per diet) received linoleic acid- or oleic acid-rich oils during the last 86 d of a 116-d feeding period. Ruminal pH, ammonia concentration, protozoal counts, major VFA concentrations, acetate-to-propionate ratio, polysaccharide-degrading activities, microbial N flow to the duodenum, and the efficiency of microbial N synthesis in the rumen were not affected (P = 0.18 to 0.96) by type of oil. Type of oil had no effect on total-tract apparent digestion of nutrients (P = 0.46 to 0.98). Ruminal true nutrient digestibilities did not differ between oils (P = 0.15 to 0.99), except that the linoleic acid-rich oil decreased (P = 0.05) NDF digestibility. Dry matter intake, ADG, G:F, and carcass characteristics did not differ (P = 0.11 to 0.84) between the two oils. Overall, the difference in dietary fatty acids provided to the cattle produced few changes in tissue fatty acids. Weight percentages of c9t11 CLA were unaltered by the addition of linoleic acid to the diet compared with oleic acid, probably as a result of low vaccenic acid production in the rumen, as the pathway of biohydrogenation was apparently primarily through the t10 pathway.

Effect of cutting height and genetics on composition, intake, and digestibility of corn silage by beef heifers.

This research was conducted to determine the effect of corn genetics and cutting height on the composition and nutritive characteristics of corn silage. An in situ study involving eight commercially available corn hybrids indicated main effects and interactions (P < 0.01) of hybrid and cutting height on NDF, ADF, and starch content and on in situ DM and NDF degradablility. Four ruminally cannulated Angus heifers (initial BW = 378 +/- 3 kg) were used in a 4 x 4 Latin square digestion experiment with a 2 x 2 factorial treatment arrangement. Main effects and interactions of hybrid (Pioneer Hi-Bred Int., Inc., hybrids 3335 and 3223) and cutting height (LO = 20.3 cm, and HI = 61 cm) were evaluated. Dietary treatment consisted of 40% chopped alfalfa hay and 60% corn silage. Although corn silage hybrids used were of equivalent maturity at harvest (60% milkline), 3335 treatments had 37.8% starch and 34.8% NDF, whereas 3223 treatments had 33.7% starch and 38.6% NDF. The LO treatments averaged 3.1 percentage units greater in NDF and 3.45 percentage units less in starch content than the HI treatments. Intake of DM was greater for heifers fed 3335-HI than 3335-LO; however, DMI was greater by heifers fed 3223-LO than 3223-HI (hybrid x cutting height interaction, P < 0.05). Starch intake was greater (P < 0.05) and NDF intake was less (P < 0.05) by heifers fed HI vs. LO and fed 3335 vs. 3223 dietary treatments. Digestibility of DM, starch, and NDF was greater (P < 0.05) by heifers fed 3223 than 3335 dietary treatments, but digestibility differences were not observed (P > 0.10) between cutting heights. Rate of in situ DM and starch degradability was not affected (P > 0.10) by hybrid or cutting height; however DM degradability was greater (P < 0.05) for HI than LO corn silage substrates at 8, 16, and 24 h of incubation. Rate of NDF degradability tended (P = 0.08) to be greater for 3223 than for 3335, and for LO compared with HI corn silage. Degradability of NDF was greater (P < 0.05) for 3223 compared with 3335 substrates at 24, 36, and 48 h of incubation. These data suggest fiber may not be an accurate measure of corn silage quality. Whereas cutting height affected chemical composition, we observed genetics to have a greater effect on corn silage quality.

Acid resistance of Escherichia coli O157:H7 from the gastrointestinal tract of cattle fed hay or grain.

There has been strong debate as to whether feeding cattle hay prior to slaughter will reduce the number and/or virulence of Escherichia coli O157:H7 in the bovine gastrointestinal tract (GIT). This study addressed this issue by comparing numbers, persistence, and acid resistance of generic coliforms and E. coli O157:H7 from various gastrointestinal tract sites of cattle fed grain or hay. Mature Angus steers, doubly cannulated into the rumen and duodenum were inoculated with E. coli O157:H7. Aliquots of digesta from the rumen, duodenum, and rectum were cultured directly or acid shocked (pH 2.0) and then cultured to determine acid resistance. The culture technique used was as sensitive as standard immunomagnetic bead separation protocols. E. coli O157:H7 from hay-fed or grain-fed cattle were similarly acid resistant in all GIT locations. In contrast, generic coliforms from the rumen and rectum of hay-fed animals were more sensitive to an acid shock than coliforms from those GIT locations in grain-fed animals. E. coli O157:H7 colonized the most distal region of the GIT and was not consistently cultured from the rumen or the duodenum. Numbers in the upper GIT did not predict numbers or persistence of E. coli O157:H7 in rectal samples. Grain-feeding or hay-feeding did not affect survival of E. coli O157:H7 in the rumen, nor its passage through the abomasum (pH 2.0) to the duodenum. These data show that generic coliforms behave differently in the bovine host than E. coli O157:H7 and that E. coli O157:H7 acid resistance was independent of animal diet.

Effect of hybrid, maturity, and mechanical processing of corn silage on intake and digestibility by beef cattle.

A study involving a 2 x 2 x 2 factorial arrangement of treatments was conducted to evaluate effects of hybrid (Pioneer 3335 and 3489), maturity (half milkline and blacklayer), and mechanical processing (field chopper with and without on-board rollers engaged) on intake and digestibility of corn silage. Forty Angus steers (322 +/- 5.2 kg BW) were assigned to the eight silage treatments (five steers per treatment) and individually fed using electronic gates. Diets consisted of 60% corn silage and 40% chopped alfalfa hay (DM basis). Following a 5-d adaptation period, intake was measured for 7 d and subsequently fecal samples were collected for 5 d. Chromic oxide (5 g/d) was fed beginning 7 d before fecal sample collection and digestibility was determined by the ratio of Cr in the feed and feces. Steers were reallocated to treatments and these procedures were repeated, providing 10 observations per treatment. In addition, all silages were ruminally incubated in six mature cows for 0, 8, 16, 24, 48, and 96 h to determine extent and rate of DM, starch, NDF, and ADF disappearance. Processing increased DMI of hybrid 3489 but did not affect DMI of hybrid 3335 (hybrid x processing; P < 0.06). Total tract digestibility of DM, starch, NDF, and ADF decreased (P < 0.01) as plant maturity increased. Maturity tended to decrease starch digestibility more for hybrid 3489 than for hybrid 3335 (hybrid x maturity; P < 0.10). Processing increased (P < 0.01) starch digestibility but decreased (P < 0.01) NDF and ADF digestibility, resulting in no processing effect on DM digestibility. There was a numerical trend for processing to increase starch digestibility more for latethan for early-maturity corn silage (maturity x processing; P = 0.11). Processing increased in situ rates of DM and starch disappearance and maturity decreased in situ disappearance rates of starch and fiber. These data indicate that hybrid, maturity, and processing all affect corn silage digestibility. Mechanical processing of corn silage increased starch digestibility, which may have been associated with the observed decreased fiber digestibility.

Effects of feeding high-oil corn to beef steers on carcass characteristics and meat quality.

To assess the effects of feeding high-oil corn on carcass characteristics and meat quality, 60 yearling steers were fed high concentrate diets containing either control corn (82% of diet), high-oil corn (82% of diet), or high-oil corn at a concentration that was isocaloric with the control diet (74% of diet). After being fed for 84 d, steers were slaughtered. At 72 h postmortem, carcass data were collected and rib sections from five steers grading U.S. Choice and five steers grading U.S. Select from each treatment were collected, vacuum packaged, and aged for 14 d. Three steaks (2.54 cm thick) were removed from each rib for Warner-Bratzler shear force measurement, sensory appraisal, and fatty acid composition analyses. Data were analyzed with treatment as the main effect for the carcass data and treatment, quality grade, and two-way interaction in the model for the longissimus data. The two-way interaction was nonsignificant (P > 0.05) for all variables tested. No differences were detected (P > 0.05) in carcass measurements except for marbling scores and quality grades, both of which were greater (P < 0.05) for carcasses from steers fed the high-oil corn. Overall, 78% of steers fed the high-oil corn graded U.S. Choice compared with 47% for the control and 67% for isocaloric group. Shear force and sensory properties of the longissimus were not different (P > 0.05) among treatments. Steaks from U.S. Choice carcasses rated higher (P < 0.05) for tenderness and tended to rate higher (P < 0.10) for juiciness. Feeding the isocaloric and high-oil diets increased (P < 0.05) linoleic acid, arachidonic acid, and the total PUFA content of lipid extracted from the longissimus. Saturated fatty acid percentage was lowest (P < 0.05) for high-oil corn and highest (P < 0.05) for control, with isocaloric being intermediate. Feeding high-oil corn increased (P < 0.05) pentadecyclic acid, margaric acid, and total odd-chain fatty acid content. Feeding high-oil corn in finishing beef cattle diets enhanced intramuscular lipid deposition and increased unsaturation of fatty acids of the longissimus.

Effect of high-oil corn on growth performance, diet digestibility, and energy content of finishing diets fed to beef cattle.

Sixty crossbred beef steers (initial BW = 412 kg) were used in a 83-d finishing study to determine the effect of feeding dry rolled high-oil corn on performance and total-tract digestibility of finishing diets. Steers were allotted by weight to the following dietary treatments: 1) control corn (C; 82% normal corn, 12% triticale silage), 2) high-oil corn (HO; 82% high-oil corn, 12% silage), and 3) high-oil corn formulated to be isocaloric to C (ISO; 74% high-oil corn, 20% silage). Total lipid content was 4.9% (DM basis) for normal corn and 7.0% for high-oil corn. Steers were individually fed using electronic gates. Quantity of feed offered and refused was recorded daily. Fecal samples were collected on d 63 to 66 of the trial to determine digestibility. Chromic oxide was fed as an indigestible marker for 7 d before fecal collection began. Planned contrasts of HO vs C and ISO vs C were used to assess treatment differences. Dry matter intake was greater for steers fed C vs HO (P < 0.01) or C vs ISO (P < 0.01), but daily gain and feed efficiency were not affected (P > 0.05) by treatments. Digestibility of DM, OM, starch, and GE was greater (P < 0.05) for the HO diet than the C diet, but lipid digestibility did not differ among treatments (P > 0.05). The combined effect of greater GE content and digestibility resulted in greater (P < 0.01) DE content for the HO than for the C diet. Calculated DE of the corn was 8.3% greater (3.74 Mcal/kg; P < 0.01) for the HO diet and 6.5% greater (3.67 Mcal/kg; P < 0.01) for the ISO diet than the corn in the C diet (3.25 Mcal/kg). Dry matter and GE digestibility did not differ (P > 0.05) between the C and ISO diets. Steers consuming ISO had greater (P < 0.05) starch digestibility than steers fed the C diet. Although HO had higher DE, DE intake was similar (P > 0.05) for HO and C due to lower DMI for HO. These results indicate that available energy is greater from high-oil corn than from typical corn, but depressed voluntary feed intake prevented performance improvements and resulted in equal energy intakes between high-oil corn and typical corn diets.

Ruminant gastrointestinal cell proliferation and clearance of Escherichia coli O157:H7.

Human infections with Escherichia coli O157:H7 cause hemorrhagic colitis that can progress to a life-threatening sequelae. The most common mode of disease transmission is ingestion of contaminated bovine food products, and it is well established that E. coli O157:H7 is a transient member of the bovine microbiota. However, the conditions that induce acquisition and subsequent clearance of this bacterium from the ruminant gastrointestinal tract (GIT) are not understood. Evidence that the rates of epithelial cell proliferation in the lower GIT of cattle are associated with the duration animals remained E. coli O157:H7 culture positive is presented. Cattle with slower rates of intestinal cell proliferation in the cecum and the distal colon were culture positive significantly longer than cohort cattle with faster cell proliferation rates. Cell death rates (apoptotic indices) between the short- and long-term culture-positive animals were not different. Typical grain-based finishing diets and forage-based growing diets did not effect GIT cell proliferation or the duration animals remained E. coli O157:H7 culture positive. To identify a dietary intervention that would effect GIT cell proliferation, we used sheep as a model ruminant. A fasting-refeeding regime that increased the rate of GIT cell proliferation was developed. The fasting-refeeding protocol was used in cattle to test the hypothesis that feeding interventions that increase the rate of GIT cell proliferation induce the clearance of E. coli O157:H7 from the bovine GIT.

Effect of cattle diet on Escherichia coli O157:H7 acid resistance.

The duration of shedding of Escherichia coli O157 isolates by hay-fed and grain-fed steers experimentally inoculated with E. coli O157:H7 was compared, as well as the acid resistance of the bacteria. The hay-fed animals shed E. coli O157 longer than the grain-fed animals, and irrespective of diet, these bacteria were equally acid resistant. Feeding cattle hay may increase human infections with E. coli O157:H7.

Effect of direct-fed fibrolytic enzymes on the lactational performance of dairy cows.

In trial 1, 30 midlactation (213 d in milk) Holstein cows were randomly assigned to a control or enzyme treatment in a two-period crossover design and were fed a total mixed ration based on alfalfa hay and silage. Cows on the enzyme treatment received an enzyme solution containing cellulases and xylanases, which was sprayed on the forage component of the ration at a rate of 1.65 ml/kg of forage dry matter (DM) between 8 and 24 h prior to feeding. Cows consuming the forage treated with enzyme produced more milk (27.2 vs. 25.9 kg/d) and digested more DM per day than did cows fed the control forage. In trial 2, 40 early lactation Holstein cows were assigned to one of four treatments for 16 wk. Following a 2-wk covariate period, cows were assigned to 1) no enzyme treatment, 2) a low (1.25 ml/kg of forage DM) enzyme treatment, 3) a medium (2.5 ml/kg of forage DM) enzyme treatment, or 4) a high (5.0 ml/kg of forage DM) enzyme treatment. Enzymes were a 2:1 combination of cellulase and xylanase diluted in water and sprayed on a combination of alfalfa hay and silage and whole cottonseed immediately before mixing with a concentrate based on barley. Dry matter intakes were similar for cows on treatments 2, 3, and 4 and were greater than those for cows on treatment 1. Production of milk, 3.5% fat-corrected milk, and energy-corrected milk was greater for cows on treatment 3 than for cows on treatment 1. Fibrolytic enzymes applied to the forage portion of the rations prior to feeding improved lactational performance of early and midlactation cows.

Evaluation of dietary influences on Escherichia coli O157:H7 shedding by sheep.

The effect of diet, an abrupt diet change, and fasting on the shedding of Escherichia coli O157:H7 was investigated with experimentally inoculated sheep as a ruminant model. Sheep were fed a grass hay diet (G), which was low in protein and digestible energy and high in fiber, or a mixture of corn and pelleted alfalfa (C), which was high in protein and digestible energy and low in fiber. After a single oral inoculation of E. coli O157:H7, all the animals shed fecal E. coli O157:H7. However, sheep that were fed G shed the bacterium almost twice as long as, and in larger numbers than, did sheep that were fed C. The number of culture-positive animals increased after the diet was abruptly changed from C to G and decreased with the opposite change (G to C). A 24-h fast did not influence E. coli O157:H7 shedding. Horizontal transmission of infection between animals occurred. Recent shedding of E. coli O157:H7 did not affect recolonization with E. coli O157:H7. The findings presented in this study indicate that preharvest control of diet may reduce the risk of E. coli O157:H7-positive animals entering the food chain.

Effect of forage:concentrate ratio on digestion and reproduction in primiparous beef heifers.

We evaluated the effects of high- (HF) and moderate- (MF) forage diets on digestive and reproductive characteristics in beef heifers. Thirty primiparous beef heifers were allotted by weight and backfat thickness to receive either 80:20 (HF) or 50: 50 (MF) forage:concentrate ratio diets from parturition to at least 90 d postpartum. Alfalfa hay and wheat straw were the forage sources and barley was the concentrate source. Equal daily amounts of ME were provided to all heifers by restricting intake of the MF diet. Digestibility of DM was greater (P < .001) for MF compared with HF diets, whereas NDF digestibility was not different. Dry matter and NDF digested daily was lower (P < .001) for MF than for HF diets. Ruminal fluid pH was lower (P < .05) for MF diets; however, the acetate:propionate ratio was not different. Serum insulin concentrations were greater for MF diets for all hours (P < .001) and weeks (P < .05) of sampling. Changes in weight, backfat thickness, and body condition score at 90 d postpartum were not different between treatments. Calf gain to 30 d, however, was greater (P < .10) for the MF than for the HF treatment (25.5 vs 20.7 kg). Maximum size of the ovulatory follicle was greater (P < .10) for cows receiving the HF diet than for cows receiving the MF diet. However, other aspects of ovarian follicular growth and wave dynamics and the intervals from parturition to first and second ovulation, first estrus, first service, and conception were not different between treatments. Shifts in energy supply from forage to concentrate had minimal effect on digestion and reproduction in first-calf beef heifers in this study.