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1.
Effects of extent of barley rolling on chewing activities, ruminal fermentation, and site and extent of digestion were evaluated for feedlot finishing cattle diets in a 4 x 4 Latin square design. Four Jersey steers (452 kg), cannulated in the rumen and duodenum, were used. Barley grain was temper-rolled to four extents: coarse, medium, medium-flat, and flat, which were expressed as processing index (PI, volume weight of barley after processing expressed as a percentage of its volume weight before processing, DM basis) and equivalent to 82, 75, 70, and 65%, respectively. Diets consisted of 9.7% barley silage, 86% temper-rolled barley, and 4.3% other ingredients (DM basis). Steers were offered ad libitum access to a total mixed ration once daily. Dry matter intake was not affected (P > 0.15) by PI of barley. Digestibility of OM in the rumen and in the total tract were numerically lower (P = 0.13) for steers fed coarsely rolled barley than for steers fed more extensively processed barley. Digestibility of starch in the total tract was linearly increased (P = 0.02) with grain processing, but NDF digestion was not affected by processing (P > 0.15). Digestibility of CP did not differ in the rumen but tended (P = 0.08) to increase in the total tract with increased processing of barley. Flow of microbial nitrogen to the duodenum was approximately one-third lower (linear effect, P = 0.06) for steers fed coarsely rolled barley than for steers fed further rolled barley. Increased grain processing tended to decrease (linear effect, P = 0.08) rumination time without affecting eating time. These results indicate that optimal degree of rolling for barley fed to feedlot cattle corresponded to a PI of 75% or lower. Coarsely rolled barley is not recommended because it resulted in the lowest digestibility and lowest microbial protein synthesis. Processing barley to attain a PI less than 75% resulted in marginal improvements in feed digestion, but rumination time decreased, which could lead to problems associated with acidosis if lower-fiber diets are used.  相似文献   

2.
This experiment was conducted with stocker steers to determine the effects of supplementary fiber and grain on ruminal acid concentrations and OM intake following abrupt dietary change to lush, primary-growth wheat (Triticum aestivum) pasture and to measure the effects of those supplements on weight gain at different levels of herbage mass (HM). Each of four irrigated wheat pastures (2.4, 3.6, 4.9, and 6.1 ha) was stocked with nine Angus crossbred steers (mean = 189 kg). In each pasture, three steers were individually fed a daily supplement of 11.3 g of cottonseed hulls (CSH)/kg BW(.75), three steers were fed a supplement mixture of 11.3 g CSH/kg BW(.75) and 8.5 g corn grain/kg BW(.75), and three steers remained as controls. Body weight and HM changes were measured at 28-d intervals throughout the experiment. Ruminal samples for VFA determination were collected twice during the 1st wk on pasture. Organic matter intake calculations were based on fecal output and OM digestibility estimates made during the 2nd wk on pasture. Fecal outputs were estimated from nonlinear least squares analyses using a two-compartment rumen model of excretion patterns of Yb following a single oral dose. Digestibility of OM was estimated using indigestible NDF in feed and feces as an internal marker. Dietary supplements had no detectable effect on ruminal VFA characteristics. The magnitude of changes in ruminal acetate:propionate ratios between d 3 and 7 on pasture was significantly and negatively related to ADG during the first 28-d growth measurement period. Body condition scores taken on d 0 also had a significant, negative relationship to ADG. Average fecal output was greater for steers fed supplements (36 g/kg BW(.75)) than for control steers (30 g/kg BW(.75)) (P < .03). The supplements also significantly reduced estimates of total diet OM digestibility. However, supplements had no measurable effect on BW changes. Herbage mass up to 1,000 kg/ha had a significant and positive effect on ADG, which was 1.44 kg during Period 1, when HM was apparently not limiting in any pasture. The deduced threshold level of the influence of HM on ADG was 850 kg/ha. Under the conditions of this experiment, the effects of supplemental fiber and(or) grain on fecal output and OM digestibility were detected. However, in the amounts fed, these supplements had no detectable effect on ADG at any level of HM.  相似文献   

3.
The objectives of this study were to evaluate the effects of dirlotapide, a microsomal triglyceride transfer protein inhibitor, on apparent nutrient digestibility of an expanded dry dog food, on defecation frequency and fecal consistency. Eighteen beagles were randomized to either placebo ( n  = 6) or dirlotapide ( n  = 12). Testing was divided into a 21-day adaptation phase (days −21 to −1) and a 35-day treatment (digestibility testing) phase (days 0–35). During the treatment phase, dogs were administered oral dirlotapide (0.3 mg/kg) or placebo (0.06 mL/kg) once daily. For digestibility testing, feces were collected over two periods for 7 days each starting on days −9 and 28. All dogs were fed a commercial adult dog food throughout the study. Food intake was adjusted to maintain body weight during adaptation, followed by pair-feeding placebo dogs the amount of food ingested by the dirlotapide dogs during the treatment period. Dogs in both groups had reduced food intake and lost similar amounts of body weight during treatment. Dogs receiving 0.3 mg dirlotapide/kg once daily had a small but significant ( P  = 0.018) decrease (6.16 ± 2.22%, mean ± SD) in crude fat digestibility compared with the placebo-treated food-restricted dogs, but no difference in crude protein, dry matter, or energy digestibility was observed. Fecal consistency and volume and defecation frequency were similar between groups. Dirlotapide effectively reduced appetite and energy intake without affecting nutrient digestibility, except for a minimal decrease in fat digestibility.  相似文献   

4.
Two 25-d trials (late summer and early winter) were conducted to determine the influence of supplementation method on forage use and grazing behavior. Fifteen ruminally and 12 esophageally fistulated steers (316 and 400 kg, respectively) were blocked by weight and assigned randomly to one of three treatments: 1) self-feeding supplement (via Calan gates) with salt as a limiting agent; 2) daily hand-feeding supplement plus salt; and 3) daily hand-feeding supplement without salt. Supplement intake was restricted to .95 kg.steer-1.d-1 with .23 and .40 kg of salt.steer-1.d-1 during summer and winter, respectively. Neither season nor supplementation method affected forage (1.64% of BW) or total (1.89% of BW) OM intake (P greater than .10). Total OM digestibility was greater (P less than .05) in the summer, in salt-supplemented steers, and when steers were self-fed supplement. Digestibility of NDF was greater (P less than .05) in the summer than in early winter, but did not differ among treatments (P greater than .10). Fluid dilution rate was greater (P less than .05) for salt-fed and self-fed steers during the summer but similar among treatments (P greater than .10) during the winter. Total VFA concentrations did not differ among treatments during summer, but were slightly greater (P = .07) in hand-fed steers during the winter. Steers fed supplements containing salt consistently displayed lower (P less than .01) acetate:propionate ratios, and self-fed steers had lower (P less than .01) acetate:propionate ratios during the summer. Ruminal ammonia concentrations did not differ (P greater than .10) among treatments and between periods.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   

5.
Twelve Angus (237 +/- 13 kg) and twelve Holstein (235 +/- 15 kg) steers were used to determine whether corn silage-based diets with different NDF levels influence DMI to a similar extent in Angus and Holstein steers and as body weight of the steers increase. Steers were randomly assigned to individual slatted-floor pens and used in a crossover design consisting of six 14-d periods. Experimental diets contained corn silage from a normal hybrid (low-fiber; LF) and its male-sterile counterpart (high-fiber; HF) and were alternated each period. The LF and HF diets contained 33.8 and 50.8% NDF, respectively. The HF diet decreased (P < 0.01) overall steer mean DMI 14.0% relative to LF, with mean differences increasing as steers increased in BW (P < 0.01). Feeding the HF diet also reduced ADG by an average of 13.8% relative to the LF diet (P < 0.01). Holstein steers consumed 14.4% more DM and gained 14.3% faster (P < 0.01) than Angus steers. There was a fiber level x breed-type interaction (P = 0.08) for efficiency of gain. Angus steers receiving the HF diet had greater efficiency of gain than Angus steers consuming the LF diet; however, Holstein steers consuming the LF diet had greater efficiency of gain than those receiving the HF diet. The HF treatment reduced total-tract digestibility of DM and GE by 4.6 and 4.5%, respectively (P < 0.01), and decreased DE intake by 20.5% (P < 0.01) but increased apparent totaltract digestibility of NDF and ADF (9.4 and 8.4%, respectively; P < 0.01). Holstein steers had similar digestibility of DM and GE (P > 0.10) but had greater DE intake (P < 0.01) compared to Angus steers. There were fiber level x breed-type interactions for total-tract digestibility of NDF and ADF (P < 0.06). The difference in DM digestibility was negatively associated with the difference in DMI (r2 = 0.23; P < 0.01) for LF minus HF within Angus steers, but not within Holstein steers (P = 0.42). Total-tract digestibility of NDF and ADF was 4.1 and 3.4% lower for the HF diet but was only 1.1 and 0.6% lower for the LF diet when fed to Holstein compared to Angus steers. Results from this trial demonstrate that high-NDF corn silage-based diets reduced intake of both Angus and Holstein steers, and this reduction in DMI continued as steers increased in BW from 235 to 330 kg. Breed differences were also noted for digestible energy intake as influenced by fiber level.  相似文献   

6.
This study aimed to examine the effects of feeding kraft pulp (KP) on the growth performance, feed digestibility, and rumen fermentation of Japanese Black fattening steers. Ten Japanese Black fattening steers (aged 26 months) were randomly divided into control and KP groups. The control group (n = 5) was fed concentrate feed without KP, and the KP group (n = 5) was fed concentrate feed containing 10% KP. Both the groups were provided rice straw as roughage. The experiment was conducted over a period of 12 weeks. There was no significant difference in dry matter intake, daily body weight gain, and nutrient digestibility between both groups. No difference was observed in the ruminal concentrations of volatile fatty acids among the groups. At weeks 8 and 12 after the onset of the experiment, the acetate‐to‐propionate ratio in the ruminal fluid of the KP group was significantly higher than that of the control group. The average daily pH of ruminal fluid and activity of ruminal lipopolysaccharide did not differ between the groups. Our results suggested that the growth performance and feed digestibility in the Japanese Black fattening steers were not influenced by replacing concentrate feed with KP.  相似文献   

7.
Oesophageal fistulated steers were used to sample herbage daily during periods of occupation on veld in good and moderate condition. Forage quality was assessed in terms of in vitro dry matter digestibility and digestible crude protein. The quality of herbage ingested remained fairly constant as forage availability declined during periods of occupation, even when swards were grazed very severely. Digestibility declined somewhat from spring through to winter, but digestible crude protein content in the diet was unaffected by time of year. The quality of forage ingested during winter was nevertheless still high, even after a full growing season's rest. It was sufficient for growing steers to gain 0,75 kg livemass per day. Trends were similar on both veld condition types. It was concluded that, in semi‐arid grassveld of the eastern Cape, forage availability is likely to have a greater influence on animal performance than forage quality.  相似文献   

8.
The effects of rose bengal, erythrosin B and fluorescein on ruminant digestion were evaluated by an in vitro rumen technique. Rose bengal reduced in vitro dry matter disappearance (IVDMD) values starting at .5 mM in the nutrient media and erythrosin B reduced IVDMD values starting at .05 mM in the nutrient media. Maximum reduction in IVDMD values was observed at 3.0 mM of rose bengal and erythrosin B. Fluorescein depressed digestion but not as severely as rose bengal or erythrosin B. Dry matter digestibility (DMD) values for steers given erythrosin B at a daily dosage of 6.5 mg/kg body weight were higher (P less than .05) than DMD values for control steers. DMD values were higher for steers given 16.3 or 26.1 mg erythrosin B/kg body weight daily than for the control steers, but the differences were not significant. There were no significant differences among animals given the different dosages in digestible energy. Recovery of erythrosin B from feces of treated steers varied with time, indicating that steers fed erythrosin B at a dosage of 6.5 mg/kg body weight might excrete feces during some periods of the day which would not control face fly development; however, administration of erythrosin B at a dosage of 16.3 mg/kg body weight would provide enough erythrosin B in feces to control face fly development throughout a 24-h period.  相似文献   

9.
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.  相似文献   

10.
Three experiments were conducted to determine effects of restricting intake of the final finishing diet as a means of dietary adaptation compared with diets increasing in grain over a period of 20 to 22 d on overall cattle performance, carcass characteristics, digestibility, digesta kinetics, and ruminal metabolism. In Exp. 1, 84 Angus x Hereford yearling steers (initial BW = 418 +/- 29.0 kg) were fed for 70 d. Restricting intake during adaptation had no effect (P > 0.10) on overall ADG:DMI, but decreased (P < 0.05) DMI compared with ad libitum access to adaptation diets, which resulted from differences during the initial 28 d of the experiment. In Exp. 2, 150 mixed crossbred steer calves (initial BW = 289 +/- 22.9 kg) were fed for an average of 173 d. Restricting intake decreased (P < 0.01) overall daily gain (1.51 vs 1.65 kg/d) and DMI (8.68 vs 9.15 kg/d) compared with ad libitum fed steers; however, ADG:DMI was not influenced (P > 0.10) by adaptation method. Experiment three used eight ruminally and duodenally fistulated steers (initial BW = 336 +/- 20 kg) in a completely random design. Total tract digestibility, digesta kinetics and ruminal metabolism were determined. Restricting intake reduced (P < 0.10) daily DMI variation from d 1 through 7, 8 through 14, and 22 through 28 compared with ad libitum feeding of three adaptation diets. Restricted steers had reduced (adaptation method x period interaction, P < 0.05) intakes and fecal excretions of ADF and greater OM digestibilities on d 4 through 7, 11 through 14, and 18 through 21. Digesta kinetics and ruminal metabolism were generally not affected (P > 0.10) by adaptation method. Our results suggest that restricted-feeding of the final diet as a means of dietary adaptation can be used in finishing cattle with few problems from acidosis or related intake variation. In light-weight steers (Exp. 2), disruptions in intake during the adaptation period might have resulted in restriction for an extended period, which decreased (P < 0.01) hot carcass weight compared with calves fed ad libitum. Effects of limit feeding during the initial 28 d of the feeding period on site and extent of digestion, digesta kinetics, and ruminal metabolism were minimal, supporting few differences in performance across the finishing period for yearling cattle.  相似文献   

11.
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.  相似文献   

12.
文章旨在探讨日粮添加不同水平的纤维素对猪生长性能、养分表观消化率和磷损失的影响。试验将平均初始体重为（48.68±0.29）kg的320头生长猪随机分为4组（T1～T4）,每组4个重复,每个重复20头。各组饲喂不同纤维素水平的无磷日粮,纤维素水平分别为0、30、60和90?g/kg,试验共开展21?d。结果：不同纤维日粮对猪末重、日增重、总磷和内源性磷排放量的影响均无显著差异（P＞0.05）。T3组平均日采食量较T1和T4组分别显著提高7.13%和7.23%（P＜0.05）,但T4组料重比较T2和T3组分别显著降低3.65%和4.95%（P＜0.05）。T1组粪磷排泄量分别较其他组显著提高229.41%、460%和460%（P＜0.05）。T3和T4组粪中干物质含量最高（P＜0.05）,T4组粪中有机物含量显著高于T1和T2组（P＜0.05）。T1组粪中粗蛋白质、粗脂肪和钙含量均显著高于其他组（P＜0.05）。T1组总能、干物质、有机物、粗蛋白质及钙表观消化率均显著高于T3和T4组（P＜0.05）。结论：随着日粮纤维素水平的升高,能量、干物质、有机物、粗蛋白质和钙表观消化率降低,但日粮纤维素水平对内源性磷损失无负面影响。 [关键词]纤维水平|猪|生长性能|养分消化|磷代谢  相似文献   

13.
Four feeding trials were conducted to determine (1) how the organophosphate ronnel affects thyroid and adrenal circulating hormone levels and blood profile measurements of beef steers and (2) whether the effects of ronnel observed in beef steers could be produced in growing rats. In trial 1, four groups of eight steers each were given either no ronnel or 4 mg ronnel/kg body weight daily in diets fed at either limited (1.8% of body weight) or ad libitum intake. After 7 weeks, intake levels, but not ronnel treatments, were reversed during a 1-week transition period, and feeding was continued for another 7 weeks. In trial 2, four groups of six steers each were given 0, 44, 88 or 176 ppm ronnel premixed in diets fed ad libitum for 18 weeks. Actual ronnel intakes averaged 0, 1.01, 2.12 and 4.73 mg/kg body weight daily in trial 2. In trials 3 and 4 , growth and intake were measured in 64 and 32 growing Sprague-Dawley rats, respectively, fed levels of ronnel ranging from 0 to 100 ppm in the diet. In trial 3, blood plasma was analyzed at various times for triiodothyronine (T3), thyroxine (T4), cholesterol and total lipid content. In trial 1, the concentration of Plasma T4 was 1.31 times higher in steers fed ronnel that in control steers. In trial 2, plasma T4 was 1.30 times higher in steers fed 176 ppm ronnel, the level that improved growth, than in steers fed the lower ronnel levels. Circulating levels of T3, cortisol and aldosterone were similar for both control and ronnel-fed steers. Serum cholesterol concentrations were consistently higher in ronnel-fed steers. The data indicated that the growth-promoting effect of ronnel in steers may be associated with a shift in thyroid function. Effects of ronnel in steers were not observed in rats, demonstrating a species difference between steers and rats.  相似文献   

14.
This study was conducted to determine whether feeding different physical forms of hay alters nutrient digestibility and nitrogen retention (NR). Six Quarter Horse geldings were assigned to any one of three different dietary treatments in three 14-day periods. The diets included long-stem Bermuda grass hay (G), long-stem alfalfa hay (A), and alfalfa cubes (C). In the final 4 days of each period, horses were fitted with harnesses for total collection of urine and feces. Samples of feed, orts, feces, and urine were analyzed for dry matter, organic matter, acid detergent fiber, neutral detergent fiber, and nitrogen (N). Digestibility of dry matter, organic matter, and N was greatest for A, intermediate for C, and smallest for G (P < .05). Digestibility of acid detergent fiber was greater (P < .05) for A than G or C, and neutral detergent fiber digestibility was greater (P < .05) for A or G than C. Nitrogen intake (NI) was greatest for A, intermediate for C, and smallest for G (P < .05). Fecal N excretion was not different between diets, but urine N excretion was greater (P < .05) for A and C as compared with G. When expressed as a percentage of NI, NR did not differ among diets. We concluded that NR in mature horses increases with NI, but N utilization is not significantly influenced by the physical form or crude protein content of the hay fed. Potential differences in fiber digestibility and daily fecal output are factors to consider when incorporating processed forages into feeding programs of horses.  相似文献   

15.
为研究日粮磷（P）水平对空怀云南半细毛羊养分消化率的影响，选择25只空怀期云南半细毛羊随机分为5组，分别饲喂5种不同磷水平（0.19%、0.32%、0.45%、0.56%和0.64%）日粮，14 d预饲期后进行消化试验（5 d）。采样期每天采集各组精料200 g，粗料200 g。每只羊的鲜粪样混匀称重后取20%分成两份，一份按5%的比例加入10%的稀盐酸进行固氮。每天采集的饲料样和粪样经55℃风干后回潮24 h，粉碎过40目筛，进行相应指标的测定。结果表明：日粮磷水平对钙（Ca）的表观消化率无影响（P>0.05）。随着日粮磷水平的增加，干物质（DM）和粗蛋白质（CP）表观消化率逐渐降低，且0.19%、0.32%磷水平组极显著高于0.64%磷水平组（P<0.01）；能量（EG）、粗脂肪（EE）、粗灰分（Ash）、中性洗涤纤（NDF）和酸性洗涤纤维（ADF）表观消化率逐渐升高后降低再逐渐升高，拐点出现在0.45%磷水平组。随着日粮磷水平的增加，磷的表观消化率逐渐降低，0.19%磷水平组极显著高于0.45%、0.56%、0.64%磷水平组（P<0.01），其他组间差异不显著（P>0.05）。通过回归分析发现，日粮磷水平与干物质、粗蛋白质、磷的表观消化率之间呈显著的线性关系（R2分别为0.7823、0.8386、0.9976）。综上所述，在本试验条件下，日粮磷水平对空怀期云南半细毛羊钙的表观消化率无影响，随日粮磷水平的增加，干物质、粗蛋白质和磷的表观消化率逐渐降低。当日粮磷水平为0.32%时空怀期云南半细毛羊对主要营养成分的表观消化率最高。  相似文献   

16.
Considering the different potential benefits of divergent fiber ingredients, the effect of 3 fiber sources on energy and macronutrient digestibility, fermentation product formation, postprandial metabolite responses, and colon histology of overweight cats (Felis catus) fed kibble diets was compared. Twenty-four healthy adult cats were assigned in a complete randomized block design to 2 groups of 12 animals, and 3 animals from each group were fed 1 of 4 of the following kibble diets: control (CO; 11.5% dietary fiber), beet pulp (BP; 26% dietary fiber), wheat bran (WB; 24% dietary fiber), and sugarcane fiber (SF; 28% dietary fiber). Digestibility was measured by the total collection of feces. After 16 d of diet adaptation and an overnight period without food, blood glucose, cholesterol, and triglyceride postprandial responses were evaluated for 16 h after continued exposure to food. On d 20, colon biopsies of the cats were collected under general anesthesia. Fiber addition reduced food energy and nutrient digestibility. Of all the fiber sources, SF had the least dietary fiber digestibility (P < 0.05), causing the largest reduction of dietary energy digestibility (P < 0.05). The greater fermentability of BP resulted in reduced fecal DM and pH, greater fecal production [g/(cat × d); as-is], and greater fecal concentration of acetate, propionate, and lactate (P < 0.05). For most fecal variables, WB was intermediate between BP and SF, and SF was similar to the control diet except for an increased fecal DM and firmer feces production for the SF diet (P < 0.05). Postprandial evaluations indicated reduced mean glucose concentration and area under the glucose curve in cats fed the SF diet (P < 0.05). Colon mucosa thickness, crypt area, lamina propria area, goblet cell area, crypt mean size, and crypt in bifurcation did not vary among the diets. According to the fiber solubility and fermentation rates, fiber sources can induce different physiological responses in cats, reduce energy digestibility, and favor glucose metabolism (SF), or improve gut health (BP).  相似文献   

17.
Alfalfa and orchardgrass herbages of similar digestibility were harvested at early and late maturity from primary growth and conserved as direct-cut silage using formic acid and formaldehyde simultaneously. Major compositional differences between the silages were lower NDF (principally hemicellulose) and a greater N content in alfalfa than in orchardgrass. An initial group of eight steers was slaughtered with a mean BW of 222 kg, and each of the four silages was fed to comparable groups of eight Holstein steers. Ad libitum DMI per unit of metabolic BW for alfalfa silages was 128% of that for orchardgrass silages. The ADG of steers fed alfalfa silages was 132% of that of steers fed orchardgrass silages. Despite greater ad libitum intake, total gut fill, as a percentage of BW, on alfalfa silages was 77% of that on orchardgrass silages. Daily empty BW gain of steers fed alfalfa silages was 158% of that of steers fed orchardgrass silages. Daily energy retention of steers fed alfalfa silages was 180% of that of steers fed orchardgrass silages. Steers fed alfalfa silages retained 140% more protein than steers fed orchardgrass silages did, but steers fed alfalfa silages retained only 71% as much protein energy relative to their total energy retention compared with steers fed orchardgrass silages. Differences in composition of daily energy retained were almost totally a result of differences in the total daily energy retention. Late alfalfa silage produced a greater daily gain than orchardgrass silage cut 2 wk earlier because greater intake compensated for lower digestibility.  相似文献   

18.
This study assessed the influence of cattle genotype and diet on the carriage and shedding of zoonotic bacterial pathogens and levels of generic Escherichia coli in feces and ruminal contents of beef cattle during the growing and finishing periods. Fifty-one steers of varying proportions of Brahman and MARC III [0 (15), 1/4 (20), 1/2 (7), and 3/4 Brahman (9)] genotypes were divided among 8 pens, such that each breed type was represented in each pen. Four pens each were assigned to 1 of 2 diets [100% chopped bromegrass hay or a diet composed primarily of corn silage (87%)] that were individually fed for a 119-d growing period, at which time the steers were switched to the same high-concentrate, corn-based finishing diet and fed to a target weight of 560 kg. Feces or ruminal fluid were collected and analyzed at alternating intervals of 14 d or less. Generic E. coli concentrations in feces or ruminal fluid did not differ (P > 0.10) by genotype or by growing diet in the growing or finishing periods. However, the concentrations in both feces and ruminal fluid increased in all cattle when switched to the same high-corn diet in the finishing period. There was no effect (P > 0.25) of diet or genotype during either period on E. coli O157 shedding in feces. Forty-one percent of the steers were positive for Campylobacter spp. at least once during the study, and repeated isolations of Campylobacter spp. from the same steer were common. These repeated isolations from the same animals may be responsible for the apparent diet (P = 0.05) and genotype effects (P = 0.02) on Campylobacter in feces in the finishing period. Cells bearing stx genes were detected frequently in both feces (22.5%) and ruminal fluid (19.6%). The number of stx-positive fecal samples was greater (P < 0.05) for 1/2 Brahman steers (42.9%) than for 1/4 Brahman (25.0%) or 3/4 Brahman steers (22.2%), but were not different compared with MARC III steers (38.3%). The greater feed consumption of 1/2 Brahman and MARC III steers may have resulted in greater starch passage into the colon, accompanied by an increase in fecal bacterial populations, which may have further improved the ability to detect stx genes in these cattle. There was no correlation between either ADG or daily DMI and the number of positive samples of E. coli O157, Campylobacter spp., or stx genes, which agrees with our current understanding that these microorganisms occur commonly in, and with no measurable detriment to, healthy cattle.  相似文献   

19.
Experiments were conducted to determine the effects of increasing supplement protein concentration on performance and forage intake of beef cows and forage utilization of steers consuming stockpiled bermudagrass forage. Bermudagrass pastures were fertilized with 56 kg of N/ha in late August. Grazing was initiated during early November and continued through the end of January each year. Treatments for the cow performance trials were: no supplement or daily equivalents of 0.2, 0.4, and 0.6 g of supplemental protein per kilogram of BW. Supplements were formulated to be isocaloric, fed at the equivalent of 0.91 kg/d, and prorated for 4 d/wk feeding. Varying the concentration of soybean hulls and soybean meal in the supplements created incremental increases in protein. During yr 1, supplemented cows lost less weight and condition compared to unsupplemented animals (P < 0.05). During yr 2, supplemented cows gained more weight (P = 0.06) and lost less condition (P < 0.05) compared to unsupplemented cows. Increasing supplement protein concentration had no affect on cumulative cow weight change or cumulative body condition score change. Forage intake tended to increase (P = 0.13, yr 1 and P = 0.07, yr 2) in supplemented cows. Supplement protein concentration did not alter forage intake. In a digestion trial, four crossbred steers were used in a Latin square design to determine the effects of supplement protein concentration on intake and digestibility of hay harvested from stockpiled bermudagrass pasture. Treatments were no supplement; or 0.23, 0.46, and 0.69 g of supplemental protein per kilogram of BW. Forage intake increased (P < 0.05) 16% and OM intake increased (P < 0.01) 30% in supplemented compared to unsupplemented steers. Diet OM digestibility increased (P = 0.08) 14.5% and total digestible OM intake increased (P < 0.05) 49% in supplemented compared to unsupplemented steers. Supplement protein concentration did not alter forage intake, total digestible OM intake, or apparent digestibility of OM or NDF. During the initial 30 d after first killing frost, beef cows did not respond to supplementation. However, later in the winter, supplementation improved utilization of stockpiled bermudagrass forage.  相似文献   

20.
The utility of five water soluble markers (WSM) for measuring rumen liquid volume and dilution rate was examined in nine in vitro and in vivo experiments. The WSM tested included polyethylene glycol (PEG) and ethylenediaminetetraacetic acid (EDTA) complexes of Cr, Co, Fe and Yb. Feedstuffs incubated in vitro absorbed variable amounts of distilled H2O and autoclaved rumen fluid with roughages imbibing greater (P less than .05) amounts of fluid than feeds higher in starch. Liquid present in the feeds tested reached equilibrium with added WSM in about 20 min. Corn grain in the whole or ground form appeared to exclude 4 to 16% of the WSM while imbibing water. Cottonseed hulls reduced detectable PEG due to some water soluble substance present. The WSM tested did not produce different estimates of dilution rate (P = .65) and volume (p = .29) of steers fed either 80% whole shelled corn, 90% chopped alfalfa hay or 90% prairie hay diets. Ruminal liquid measured by hand removal was about 4% greater than volume estimated by WSM. The percentage of total ruminal water associated with solids varied from 27 to 86% among steers. Compared with steers fed an 80% whole shelled corn diet, steers fed equal dry matter from alfalfa hay had 15% more dry matter in the rumen, 21% larger liquid volume, 80% greater ruminal liquid dilution rate and 116% greater rate of liquid flow from the rumen. Dilution rate of ruminal liquid during feeding was examined with six steers fed a 90% chopped alfalfa hay diet once daily at 1.8% of body weight. Dilution rate estimated with Co EDTA increased by 166% during the 4 h after feeding. The WSM did not influence (P greater than .10) digestibility of dry matter with steers fed a 90% roughage or a 90% concentrate ration. Recovery of WSM administered via a rumen cannula ranged from 96.8 to 99.7% in feces and 1.2 to 3.4% in urine. All WSM examined appeared suitable for estimating rumen liquid volume and dilution rate for diets not containing cottonseed hulls.  相似文献   

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