Effects of concentrated separator by-product (desugared molasses) on intake, ruminal fermentation, digestion, and microbial efficiency in beef steers fed grass hay

Concentrated separator by-product (CSB) is produced when beet molasses goes through an industrial desugaring process. To investigate the nutritional value of CSB as a supplement for grass hay diets (12.5% CP; DM basis), 4 ruminally and duodenally cannulated beef steers (332 +/- 2.3 kg) were used in a 4 x 4 Latin square with a 2 x 2 factorial arrangement of treatments. Factors were intake level: ad libitum (AL) vs. restricted (RE; 1.25% of BW, DM basis) and dietary CSB addition (0 vs. 10%; DM basis). Experimental periods were 21 d in length, with the last 7 d used for collections. By design, intakes of both DM and OM (g/kg of BW) were greater (P < 0.01; 18.8 vs. 13.1 +/- 0.69 and 16.8 vs. 11.7 +/- 0.62, respectively) for animals consuming AL compared with RE diets. Main effect means for intake were not affected by CSB (P = 0.59). However, within AL-fed steers, CSB tended (P = 0.12) to improve DMI (6,018 vs. 6,585 +/- 185 g for 0 and 10% CSB, respectively). Feeding CSB resulted in similar total tract DM and OM digestion compared with controls (P = 0.50 and 0.87, respectively). There were no effects of CSB on apparent total tract NDF (P = 0.27) or ADF (P = 0.35) digestion; however, apparent N absorption increased (P = 0.10) with CSB addition. Total tract NDF, ADF, or N digestion coefficients were not different between AL- and RE-fed steers. Nitrogen intake (P = 0.02), total duodenal N flow (P = 0.02), and feed N escaping to the small intestine (P = 0.02) were increased with CSB addition. Microbial efficiency was unaffected by treatment (P = 0.17). Supplementation with CSB increased the rate of DM disappearance (P = 0.001; 4.9 vs. 6.9 +/- 0.33 %/h). Restricted intake increased the rate of in situ DM disappearance (P = 0.03; 6.4 vs. 5.3 +/- 0.33 %/h) compared with AL-fed steers. Ruminal DM fill was greater (P = 0.01) in AL compared with RE. Total VFA concentrations were greater (P = 0.04) for CSB compared with controls; however, ammonia concentrations were reduced (P = 0.03) with CSB addition. At different levels of dietary intake, supplementing medium-quality forage with 10% CSB increased N intake, small intestinal protein supply, and total ruminal VFA.     

Effects of canola seed supplementation on intake, digestion, duodenal protein supply, and microbial efficiency in steers fed forage-based diets

Fourteen Holstein steers (446 +/- 4.4 kg of initial BW) with ruminal, duodenal, and ileal cannulas were used in a completely randomized design to evaluate effects of whole or ground canola seed (23.3% CP and 39.6% ether extract; DM basis) on intake, digestion, duodenal protein supply, and microbial efficiency in steers fed low-quality hay. Our hypothesis was that processing would be necessary to optimize canola use in diets based on low-quality forage. The basal diet consisted of ad libitum access to switchgrass hay (5.8% CP; DM basis) offered at 0700 daily. Treatments consisted of hay only (control), hay plus whole canola (8% of dietary DM), or hay plus ground canola (8% of dietary DM). Supplemental canola was provided based on the hay intake of the previous day. Steers were adapted to diets for 14 d followed by a 7-d collection period. Total DMI, OM intake, and OM digestibility were not affected (P > or = 0.31) by treatment. Similarly, no differences (P > or = 0.62) were observed for NDF or ADF total tract digestion. Bacterial OM at the duodenum increased (P = 0.01) with canola-containing diets compared with the control diet and increased (P = 0.08) in steers consuming ground canola compared with whole canola. Apparent and true ruminal CP digestibilities were increased (P = 0.01) with canola supplementation compared with the control diet. Canola supplementation decreased ruminal pH (P = 0.03) compared with the control diet. The molar proportion of acetate in the rumen tended (P = 0.10) to decrease with canola supplementation. The molar proportion of acetate in ruminal fluid decreased (P = 0.01), and the proportion of propionate increased (P = 0.01), with ground canola compared with whole canola. In situ disappearance rate of hay DM, NDF, and ADF were not altered by treatment (P > or = 0.32). In situ disappearance rate of canola DM, NDF, and ADF increased (P = 0.01) for ground canola compared with whole canola. Similarly, ground canola had greater (P = 0.01) soluble CP fraction and CP disappearance rate compared with whole canola. No treatment effects were observed for ruminal fill, fluid dilution rate, or microbial efficiency (P > or = 0.60). The results suggest that canola processing enhanced in situ degradation but had minimal effects on ruminal or total tract digestibility in low-quality, forage-based diets.     

Effect of field pea level on intake, digestion, microbial efficiency, ruminal fermentation, and in situ disappearance in beef steers fed forage-based diets

Four ruminally and duodenally cannulated crossbred beef steers (397+/-55 kg initial BW) were used in a 4 x 4 Latin square to evaluate the effects of increasing level of field pea supplementation on intake, digestion, microbial efficiency, ruminal fermentation, and in situ disappearance in steers fed moderate-quality (8.0% CP, DM basis) grass hay. Basal diets, offered ad libitum twice daily, consisted of chopped (15.2-cm screen) grass hay. Supplements were 0, 0.81, 1.62, and 2.43 kg (DM basis) per steer daily of rolled field pea (23.4% CP, DM basis) offered in equal proportions twice daily. Steers were adapted to diets on d 1 to 9; on d 10 to 14, DMI were measured. Field pea and grass hay were incubated in situ, beginning on d 10, for 0, 2, 4, 8, 12, 16, 24, 36, 48, 72, and 96 h. Ruminal fluid was collected and pH recorded at -2, 0, 2, 4, 6, 8, 10, and 12 h after feeding on d 13. Duodenal samples were taken for three consecutive days beginning on d 10 in a manner that allowed for a collection to take place every other hour over a 24-h period. Linear, quadratic, and cubic contrasts were used to evaluate the effects of increasing field pea level. Total DMI and OMI increased quadratically (P = 0.09), whereas forage DMI decreased quadratically (P = 0.09) with increasing field pea supplementation. There was a cubic effect (P < 0.001) for ruminal pH. Ruminal (P = 0.02) and apparent total-tract (P = 0.09) NDF disappearance decreased linearly with increasing field pea supplementation. Total ruminal VFA concentrations responded cubically (P = 0.008). Bacterial N flow (P = 0.002) and true ruminal N disappearance (P = 0.003) increased linearly, and apparent total-tract N disappearance increased quadratically (P = 0.09) with increasing field pea supplementation. No treatment effects were observed for ruminal DM fill (P = 0.82), true ruminal OM disappearance (P = 0.38), apparent intestinal OM digestion (P = 0.50), ruminal ADF disappearance (P = 0.17), apparent total-tract ADF disappearance (P = 0.35), or in situ DM disappearance of forage (P = 0.33). Because of effects on forage intake and ruminal pH, field peas seem to act like cereal grain supplements when used as supplements for forage-based diets. Supplementing field peas seems to effectively increase OM and N intakes of moderate-quality grass hay diets.     

Effects of cooked molasses blocks and fermentation extract or brown seaweed meal inclusion on intake, digestion, and microbial efficiency in steers fed low-quality hay

Five ruminally, duodenally, and ileally cannulated steers (376 +/- 8.1 kg of initial BW) were used in a 5 x 5 Latin square to evaluate effects of cooked molasses block supplementation and inclusion of fermentation extract (Aspergillus oryzae) or brown seaweed meal (Ascophyllum nodosum) on intake, site of digestion, and microbial efficiency. Diets consisted of switchgrass hay (6.0% CP; DM basis) offered ad libitum, free access to water, and one of three molasses blocks (0.341 kg of DM/d; one-half at 0600 and one-half at 1800). Treatments were no block (control), block with no additive (40.5% CP; POS), block plus fermentation extract bolused directly into the rumen via gelatin capsules (2.0 g/d; FS), fermentation extract included in the block (2.0 g/d; FB), and seaweed meal included in the block (10 g/d; SB). Steers were adapted to diets for 14 d followed by a 7-d collection period. Overall treatment effect on hay OM intake tended (8.1 vs. 7.6 +/- 0.5 kg/d; P = 0.14) to increase with block supplementation. Total OM intake (8.4 vs. 7.6 +/- 0.5 kg/d; P = 0.01) increased in steers consuming block compared with control. Apparent and true ruminal OM digestibility increased (P = 0.05) with block consumption. Steers fed SB had greater (P = 0.10) true ruminal OM digestibility compared with steers fed POS (61.0 vs. 57.9 +/- 1.6%). True ruminal CP digestibility increased (P = 0.01) with block supplementation compared with control (37.5 vs. 23.6 +/- 3.7%). Addition of fermentation extract did not affect intake or digestion. Treatments did not alter ruminal pH, total VFA, or individual VFA proportions; however, ruminal ammonia increased (P = 0.01) with block supplementation. In situ disappearance rates of hay DM (3.14 +/- 0.44 %/h), NDF (3.18 +/- 0.47 %/h), and ADF (3.02 +/- 0.57 %/h) were not altered by treatment. Seaweed block increased (P = 0.01) slowly degraded CP fraction compared with POS (39.5 vs. 34.0 +/- 2.07%). Similarly, SB increased (P = 0.01) the extent of CP degradability (74.2 vs. 68.9 +/- 1.81%). No treatment effects (P = 0.24) were observed for microbial efficiency. Block supplementation increased intake, and use of brown seaweed meal seemed to have beneficial effects on forage digestibility in low-quality forage diets.     

Effect of field pea level on intake, digestion, microbial efficiency, ruminal fermentation, and in situ disappearance in beef steers fed growing diets

Effects of increasing level of field pea (variety: Profi) on intake, digestion, microbial efficiency, and ruminal fermentation were evaluated in beef steers fed growing diets. Four ruminally and duodenally cannulated crossbred beef steers (367+/-48 kg initial BW) were used in a 4 x 4 Latin square. The control diet consisted of 50% corn, 23% corn silage, 23% alfalfa hay, and 4% supplement (DM basis). Treatments were field pea replacing corn at 0, 33, 67, or 100%. Diets were formulated to contain a minimum of 12% CP, 0.62% Ca, 0.3% P, and 0.8% K (DM basis). Each period was 14 d long. Steers were adapted to the diets for 9 d. On d 10 to 14, intakes were measured. Field pea was incubated in situ, beginning on d 10, for 0, 2, 4, 8, 12, 16, 24, 36, 48, 72, and 96 h. Bags were inserted in reverse order, and all bags were removed at 0 h. Ruminal fluid was collected and pH recorded at -2, 0, 2, 4, 6, 8, 10, and 12 h after feeding on d 13. Duodenal samples were taken for three consecutive days beginning on d 10 in a manner that allowed for a collection to take place every other hour over a 24-h period. Linear, quadratic, and cubic contrasts were used to compare treatments. There were no differences in DMI (12.46 kg/d, 3.16% BW; P > 0.46). Ruminal dry matter fill (P = 0.02) and mean ruminal pH (P = 0.009) decreased linearly with increasing field pea level. Ruminal ammonia-N (P < 0.001) and total VFA concentrations (P = 0.01) increased linearly with increasing field pea level. Total-tract disappearance of OM (P = 0.03), N (P = 0.01), NDF (P = 0.02), and ADF (P = 0.05) increased linearly with an increasing field pea level. There were no differences in total-tract disappearance of starch (P = 0.35). True ruminal N disappearance increased linearly (P < 0.001) with increasing field pea level. There were no differences in ruminal disappearance of OM (P = 0.79), starch (P = 0.77), NDF (P = 0.21), or ADF (P = 0.77). Treatment did not affect microbial efficiency (P = 0.27). Field pea is a highly digestible, nutrient-dense legume grain that ferments rapidly in the rumen. Because of their relatively high level of protein, including field peas in growing diets will decrease the need for protein supplementation. Based on these data, it seems that field pea is a suitable substitute for corn in growing diets.     

Effects of supplemental protein type on intake, nitrogen balance, and site, and extent of digestion in whiteface wethers consuming low-quality grass hay

Two experiments were conducted to determine the effects of supplementing ruminally degradable intake protein (DIP) or ruminally undegradable intake protein (UIP) on N balance (Exp. 1; n = 6 wethers; initial BW = 48.7 +/- 4.6 kg) and site and extent of digestion (Exp. 2; n = 5 wethers; initial BW = 36.9 +/- 3.1 kg) in whiteface wethers consuming (as-fed basis) 69% blue grama and 31% love grass hay (mixture = 7.5% CP, 73.0% NDF, 36.0% ADF [DM basis]). Treatments were 1) no supplement (Control), 2) a supplement (219 g/d, as-fed basis) low in UIP (70 g/d of CP; 24.8 g/d of UIP), and 3) a supplement (219 g/d, as-fed basis) high in UIP (70 g/d of CP; 37.1 g/d of UIP). Both experiments were replicated 3 x 3 Latin square designs, with identical feeding and supplementation. Wethers had ad libitum access to the forage mixture and fresh water, and received supplement once daily. In Exp.1, forage intake (percentage of BW) was greatest (P = 0.04) for control, but total DMI (g/d) was greatest (P = 0.05) for lambs consuming supplement. Apparent total-tract OM digestibility was numerically greater (P = 0.11) for supplemented wethers than for controls, whereas total-tract ADF digestibility tended (P = 0.08) to be greater for control wethers. Lambs fed supplements consumed and retained more (P < or = 0.01) N (% of N intake) compared with controls, but no difference (P = 0.22) was observed between low and high UIP treatments. Similar to Exp. 1, forage intake (percentage of BW) tended (P = 0.06) to be greater for control than for supplemented wethers in Exp. 2. Ruminal NDF digestibility was 16.3% greater (P = 0.02) for supplemented wethers than for controls. Postruminal NDF and N digestibilities were greatest (P < or = 0.03) for controls, but apparent OM digestibility did not differ among treatments at all sites. Duodenal N flow was greatest (P = 0.05) for high UIP and least for control wethers. Nonmicrobial N flow was greater (P = 0.02) for high UIP compared with low UIP or controls. Control wethers had greater (P = 0.05) microbial efficiency. Ruminal ammonia concentration tended (P = 0.08) to be greatest for wethers fed low UIP and least for controls, with high-UIP wethers having intermediate ammonia concentrations. Results from these experiments suggest that in lambs fed low-quality forage there was no difference in apparent total-tract digestion or N balance (percentage of N intake) between lambs fed supplements that had the same CP but differed in the proportion of UIP and DIP; however, supplementing protein (regardless of UIP:DIP ratio) to wethers consuming low-quality forage increased N balance.     

Influence of pressed beet pulp and concentrated separator by-product on intake, gain, efficiency of gain, and carcass composition of growing and finishing beef steers

The objectives of this experiment were to determine a NE value for pressed beet pulp and the value of concentrated separator by-product (de-sugared molasses) as a ruminal N source in growing and finishing diets for beef cattle. One hundred forty-four cross-bred beef steers (282 +/- 23 kg of initial BW) were used in 2 experiments (growing and finishing). A randomized complete block design was used, with a 3 x 2 factorial arrangement of treatments (level of pressed beet pulp and inclusion of concentrated separator by-product) for both studies. Steers were blocked by BW and allotted randomly to 1 of 6 treatments. In the growing study, the control diet contained 49.5% corn, 31.5% corn silage, 10.0% alfalfa hay, and 9.0% supplement (DM basis). Pressed beet pulp replaced corn at 0, 20, or 40% of dietary DM, and concentrated separator by-product replaced corn and urea at 10% of dietary DM. The growing study lasted for 84 d. Initial BW was an average of 2-d BW after a 3-d, restricted (1.75% of BW) feeding of 50% alfalfa hay and 50% corn silage (DM basis), and final BW was an average of 2-d BW after a 3-d, restricted (1.75% of BW) feeding of 31.5% corn silage, 10.0% alfalfa hay, 25.0% dry-rolled corn, 20.0% pressed beet pulp, 5.0% concentrated separator by-product, and 8.5% supplement (DM basis). After the growing study, the steers were weighed (415 +/- 32 kg), rerandomized, and allotted to 1 of 6 finishing diets. The control diet for the finishing study included 45% dry-rolled corn, 40% high-moisture corn, 5% brome hay, 5% pressed beet pulp, and 5% supplement. Pressed beet pulp replaced high-moisture corn at 5.0, 12.5, and 20.0% of the dietary DM, and concentrated separator by-product replaced high-moisture corn and supplement at 10.0% of diet DM. Steers were slaughtered on d 83 or 98 of the study. In the growing study, the addition of pressed beet pulp to growing diets linearly decreased (P = 0.001) DMI and ADG and inclusion of 10% concentrated separator by-product decreased (P = 0.001) G:F. Increased levels of pressed beet pulp in the finishing diets caused a linear decrease (P = 0.001) in ADG and tended (P = 0.06 and 0.07 for kg/d and % of BW, respectively) to quadratically decrease DMI, whereas addition of concentrated separator by-product increased (P = 0.02 and 0.001 for kg/d and % of BW, respectively) DMI. Apparent NEg of pressed beet pulp was 94.2% of that of corn in the growing study and 81.5% of that of corn in the finishing study.     

Effect of undegradable intake protein supplementation on intake, digestion, microbial efficiency, in situ disappearance, and plasma hormones and metabolites in steers fed low-quality grass hay

Four ruminally and duodenally cannulated beef steers (492 +/- 30 kg) were used in a 4 x 4 Latin square design to evaluate the effect of undegradable intake protein (UIP) supplementation on intake, digestion, microbial efficiency, in situ disappearance, and plasma hormones and metabolites in steers fed low-quality grass hay. The steers were offered chopped (10.2 cm in length) grass hay (6.0% CP) ad libitum and 1 of 4 supplements. Supplemental treatments (1,040 g of DM daily), offered daily at 0800, were control (no supplement) or low, medium, or high levels of UIP (the supplements provided 8.3, 203.8, and 422.2 g of UIP/ d, respectively). The supplements were formulated to provide similar amounts of degradable intake protein (22%) and energy (1.77 Mcal of NE(m)/kg). Blood samples were taken at -2, -0.5, 1, 2, 4, 8, 12, and 24 h after supplementation on d 1 (intensive sampling) and at -0.5 h before supplementation on d 2, 3, 4, and 5 (daily sampling) of each collection period. Contrasts comparing control vs. low, medium, and high; low vs. medium and high; and medium vs. high levels of UIP were conducted. Apparent and true ruminal OM and N digestion increased (P < 0.03) in steers fed supplemental protein compared with controls, but there were no differences (P > 0.26) among supplemental protein treatments. There were no differences (P > 0.11) among treatments for NDF or ADF digestion, or total ruminal VFA or microbial protein synthesis. Ruminal pH was not different (P = 0.32) between control and protein-supplemented treatments; however, ruminal pH was greater (P = 0.02) for supplementation with medium and high compared with low UIP. Daily plasma insulin concentrations were increased (P = 0.004) in protein-supplemented steers compared with controls and were reduced (P = 0.003) in steers fed low UIP compared with steers fed greater levels of UIP. Intensive and daily plasma urea N concentrations were increased (P < 0.01) in protein-supplemented steers compared with controls and increased (P < 0.02) for intensive and daily sampling, respectively, in steers supplemented with medium and high UIP compared with low UIP. Supplemental protein increased apparent and true ruminal OM and N digestion, and medium and high levels of UIP increased ruminal pH compared with the low level. An increasing level of UIP increases urea N and baseline plasma insulin concentrations in steers fed low-quality hay.     

Influence of lysocellin and monensin on mineral metabolism of steers fed forage-based diets

Studies were conducted to determine the effects of lysocellin and monensin on mineral metabolism of steers fed forage-based diets. In each study treatments consisted of 1) control, 2) 100 mg lysocellin/d, 3) 200 mg lysocellin/d and 4) 200 mg monensin/d. Twenty-four growing Hereford steers were used in each of two experiments to evaluate the effects of ionophore feeding on plasma and ruminal soluble mineral concentrations. Steers were fed individually greenchop (tall fescue and bermudagrass) ad libitum and .91 kg/d of a corn-trace mineral salt-ionophore supplement. Plasma and ruminal fluid samples were obtained on d 28 and 84 in both studies. Ruminal concentrations of soluble phosphorus (P) and iron (Fe) were higher (P less than .05), whereas soluble manganese (Mn) was lower (P less than .01), in steers fed lysocellin than in controls. Steers fed lysocellin had higher (P less than .05) plasma magnesium (Mg) concentrations than control steers. Plasma and ruminal soluble mineral concentrations generally were similar for the monensin and 200 mg lysocellin treatments. Two additional studies were conducted to determine the effects of lysocellin and monensin on macromineral apparent absorption and retention in steers fed tall fescue greenchop. Steers were adjusted to their diets for 28 d and then placed in metabolism crates for a 6-d acclimation followed by a 5-d collection of urine and feces. Percent apparent absorption of calcium (Ca), potassium (K), Mg and P was higher (P less than .05), whereas sodium (Na) absorption was lower (P less than .05), in steers fed lysocellin than in controls. Mineral absorption was similar in steers fed 200 mg lysocellin or monensin. Calcium (P less than .05) and K (P less than .10) retention (percent of intake) was increased by ionophore feeding. Results indicate that lysocellin and monensin alter apparent absorption and retention of certain minerals in steers fed forage-based diets.     

Daily and alternate-day supplementation of urea or biuret to ruminants consuming low-quality forage: II. Effects on site of digestion and microbial efficiency in steers

Five steers (491 +/- 21 kg BW) were used in an incomplete 5 x 4 Latin square with four 24-d periods to determine the influence of supplemental non-protein N (NPN) source and supplementation frequency (SF) on nutrient intake and site of digestion in steers consuming low-quality grass straw (4% CP). Treatments (TRT) included an unsupplemented control and a urea- or biuret-containing supplement placed directly into the rumen daily (D) or every other day (2D) at 0700. The NPN treatments were formulated to provide 90% of the estimated degradable intake protein requirement. Daily TRT were supplemented CP at 0.04% of BW/d, whereas the 2D TRT were supplemented at 0.08% of BW every other day. Therefore, all supplemented TRT received the same quantity of supplemental CP over a 2-d period. Forage OM intake was not affected (P > 0.05) by NPN supplementation, NPN source, or SF; however, total OM and N intake were increased (P < 0.01) with CP supplementation. Duodenal flow of N was greater (P = 0.04) with CP supplementation compared with the control. In addition, duodenal bacterial N flow was increased with CP supplementation (P = 0.04) and for biuret compared with urea (P < 0.01). Bacterial efficiency (g bacterial N/kg OM truly digested in the rumen) was greater (P = 0.05) for biuret than for urea. Apparent total-tract N digestibility was increased with NPN supplementation (P < 0.01) but not affected by NPN source or SF. These results suggest that urea or biuret can be used effectively as a supplemental N source by steers consuming low-quality forage.     

Effects of a new molasses byproduct, concentrated separator byproduct, on nutrient digestibility and ruminal fermentation in cattle.

Continuous chromatographic separator techniques have allowed the extraction of more simple sugars from molasses (MOL). The resultant byproduct, concentrated separator byproduct (CSB), has reduced readily fermentable carbohydrates but elevated CP and mineral content. The feed value of CSB was compared to that of MOL in two separate trials. In Trial 1, a chopped forage mixture containing 84% meadow grass hay and 8% alfalfa hay was mixed with either CSB or MOL at 7.3% of DM. Diets were administered to four ruminally cannulated cows in a single reversal design. digestibility of DM, ADF, NDF, and CP were measured. Ruminal pH, ammonia nitrogen (NH3), VFA, total viable bacteria (TVB), cellulose-xylan fermenting bacteria (CXFB), and ciliated protozoa (PTZ) were evaluated. Blood profiles of electrolytes were also measured. Digestibility of DM, ADF, NDF, and CP were 69.03, 68.58; 57.48, 57.77; 65.62, 64.75; and 67.63, 65.07% for the MOL and CSB diets, respectively. Only CP digestibility differed (P less than .02). Ruminal pH, NH3, VFA, TVB, CXFB, and PTZ were 6.97, 6.93; 14.21, 16.71 mg/dL; 74.30, 74.78 mumol/mL; 26.79, 27.36 x 10(9)/mL; 21.72, 21.36%; and 13.90, 7.80 x 10(3)/mL for the MOL and CSB diets, respectively. Ruminal measurements did not differ. Blood electrolyte profiles were not altered. Trial 2 was similar to Trial 1 except the basal diet used was 47% barley grain, 35% alfalfa hay, and 10% barley straw. Either MOL or CSB was added at 7.3% of the DM. Digestibilities of DM, ADF, NDF, and CP were 69.52, 71.33; 35.96, 37.11; 27.93, 33.47; and 71.10, 73.66% for the MOL and CSB diets, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)     

Evaluation of three popular diets fed to pet sugar gliders (Petaurus breviceps): Intake,digestion and nutrient balance

Three diets fed to 12 pair‐housed sugar gliders, Petaurus breviceps, were evaluated through 5‐day intake and digestion trials following 10‐day transitions. Diets 1 and 2 comprised liquid formula mixes with added vegetables and fruit, and Diet 3 comprised extruded pellets and a liquid formula. Diets eaten contained 16 —19% crude protein, 3%–15% crude fat, 10%–11% neutral detergent fibre, 4%–20% starch and 8%–49% sugar (dry basis). Calculated individual dry matter intakes (DMI) ranged from 3.9 to 5.1 g/day, representing 58.2–78.4 kJ/day. DMI was greater for Diet 2 (7.2% BW) vs. Diet 1 (5.6; p = .006) and Diet 3 (4.2% BW; p = .003). Although these differences were no longer detectable on a MBW basis, animals were shown to have gained BW (+14.2 g; p = .03) on Diet 2. In addition to nutrient composition differing widely among diets, DM digestibility (DMD) was higher in Diet 1 (91.2%) compared to Diet 2 (87.3%; p = .03), but DMD for Diet 3 (88.9%) did not differ from other diets. Gliders demonstrated ability to digest a variety of energy substrates, including simple sugars (96%–99%), fats (81%–96%) and starches (79%–98%), as well as substantial insoluble dietary fibre (58%–75%), with significant difference among diets demonstrated for some nutrients. Animals displayed selective feeding behaviours, rejecting insoluble fibre in produce and preferring the lipid‐coated exterior of pellets. The diets used appeared to be balanced with respect to energy, protein and macromineral content, but may predispose to iron excess, other mineral imbalances (especially Ca deficiency) and obesity—clinical health issues described for pet gliders. Future focus on concentrations, types and utilization of dietary fibre in natural and captive diets, vitamin D metabolism and trace mineral interactions in sugar gliders would assist diet optimization for this highly gummivorous species.     

Effects of exogenous fibrolytic enzymes on intake,duodenal flow,and digestion in steers fed diets with whole or cracked Pima cottonseed

Abstract

This study evaluated the effects of exogenous fibrolytic enzymes on intake, ruminal fermentation, and duodenal flow and digestion of nutrients in steers fed diets with whole Pima cottonseed (WPC) or cracked Pima cottonseed (CPC). Four Holstein steers (167±5 kg body weight) fitted with ruminal and duodenal cannulas with a 4×4 Latin square in a 2×2 factorial arrangement of treatments (WPC or CPC; 0 or 15 g enzyme) were used. Steers were fed wheat flaked-based diets with 9.95% of WPC or CPC as dry matter basis. Enzymes increased molar proportion of acetate in steer fed WPC, but in those fed CPC acetate decreased. Feeding enzymes increased duodenal flow of organic matter in steers fed WPC, but not in those fed CPC. Also, enzymes increased duodenal flow of N, non-ammonia N, and intestinal digestion of N in steers fed WPC and CPC.     

Effects of methionine hydroxy analog on voluntary intake, digestibility, nitrogen balance, and chewing behavior in sheep fed grass silage

Voluntary intake, digestibility, N balance, and chewing behavior of six 6-mo-old (young) and six 30-mo-old (mature) Texel wethers (32.6 and 83.1 kg average BW) given ad libitum access to grass silage and 100 g of top-dressed soybean meal with or without 5 g of methionine hydroxy analog (MHA) in the acid form were examined according to a two-period crossover design. Supplementation level of MHA in the acid form corresponded to .32 and .16 g of MHA/kg BW.75, respectively, in young and mature wethers. There was no effect (P greater than .10) of MHA on mean voluntary DMI. Methionine hydroxy analog supplementation increased (P less than .02) digestibility of DM, OM, and CP by young wethers but not (P greater than .18) by mature wethers. The MHA decreased eating time (P less than .03) in both young and mature wethers and intake level (P = .01) in young wethers during the first 1.5 h of access to grass silage. With MHA, both age groups increased (P less than .05) the daily number of meals and decreased (P less than .02) the mean duration of each meal. There was no effect (P greater than .06) of MHA on daily and unitary eating, ruminating, and masticating times; however, mean duration of consecutive rumination bolus cycles was longer (7.2%; P = .01) in young wethers. Young vs mature sheep ate more (53.4 vs 39.3 g of DM/[d.kg BW.75]; P less than .001) and had shorter unitary mastication times (P = .001). Results suggest that, depending on its relative level of supplementation, MHA in the acid form could act through both palatability and effects on ruminal metabolism.     

Effects of restricted and ad libitum intake of diets containing wheat middlings on site and extent of digestion in steers

A 5 x 5 Latin square design was used to determine the effects of restricted and ad libitum intake of diets containing wheat middlings on the site and extent of digestion compared to ad libitum intake of a corn-based diet and ad libitum intake of chopped alfalfa hay. Five ruminally and duodenally cannulated Angus steers (519 +/- 41.5 kg BW) were used to compare five dietary treatments. The five treatments were as follows: ad libitum access to a corn-based finishing diet (control), the control diet with 25 percentage units of the corn and soybean meal replaced with wheat middlings offered ad libitum (WM), the WM diet restricted to 75% of predicted ad libitum intake (RWM), the RWM diet with wheat middlings replaced with ammoniated wheat middlings (RNWM), and ad libitum access to a chopped alfalfa hay diet. Although RWM steers were fed to consume 75% of ad libitum intake, RWM steers consumed 15.5% less DM than WM. Steers fed ad libitum hay consumed 28.6, 31.7, and 37.2% less (P < 0.01) DM, OM, and nitrogen than RWM steers. No differences in apparent or true ruminal digestibility were observed among steers fed the control vs WM, WM vs RWM, RWM vs RNWM, or RWM vs hay diets. However, the steers fed the hay diet had 32.5, 33.4, and 36.9% lower (P < 0.01) apparent total tract digestibilities of DM, OM, and N than those fed the RWM diet. Average ruminal pH was lower (P < 0.01) for control steers than those fed the WM diet and for those fed RWM compared to the hay diet. The acetate:propionate ratio was higher for cattle fed hay vs the RWM diet. Microbial DM and OM flow to the small intestine was higher (P < 0.02) for steers fed the RWM diet than those fed the hay diet. In addition, bacterial N flow to the small intestine was higher (P < 0.01) for cattle receiving the RWM diet than the hay diet. Feeding diets containing 25 percentage units of wheat middlings at 75% ad libitum intake had no effect on ruminal digestibility.     

Effects of degree of fat saturation on fiber digestion and microbial protein synthesis when diets are fed twelve times daily

Three Holstein heifers and one nonlactating cow, fitted with ruminal and duodenal cannulas, were arranged in a 4 x 4 Latin square design to determine the effects of degree of fat saturation on ruminal neutral detergent fiber digestion and microbial protein synthesis and to determine whether changes in the efficiency of microbial protein synthesis were related to protozoal populations in the rumen. Corn silage-based diets contained no added fat or 4.85% of diet dry matter as partially hydrogenated tallow, tallow, or animal-vegetable fat. Iodine values of fat sources were 12.8, 50.6, and 109.7 for partially hydrogenated tallow, tallow, and animal-vegetable fat, respectively. Cattle were fed every 2 h and consumed 1.5% of body weight as dry matter daily. Ruminal neutral detergent fiber digestibility was decreased by added fat but was not affected by increasing iodine value. Flows of microbial N and non-NH3-nonmicrobial N to the duodenum were not affected by treatment. Ruminal protozoa concentration decreased linearly as the iodine value of fats increased. The efficiency of microbial protein synthesis was increased and protozoa concentrations tended to decrease when fat was fed. Decreased ruminal protozoa concentration may have decreased intraruminal N recycling. Biohydrogenation of added fat may result in a low ruminal concentration of unsaturated fatty acids when cows are fed frequently, reducing the negative effects of unsaturated fat sources on ruminal neutral detergent fiber digestibility. Protozoa were inhibited by unsaturated fat, but it is not clear if biohydrogenation and frequent feeding lessened inhibition.     

Effect of fiber-based creep feed on intake, digestion, ruminal fermentation, and microbial efficiency in nursing calves

Six Angus crossbred cow-calf pairs (653 +/- 35 kg and 157 +/- 10 kg initial BW for cows and calves, respectively) were used to evaluate the influence of a fiber-based creep feed on intake, ruminal fermentation, digestion characteristics, and microbial efficiency in nursing beef calves. Cow-calf pairs were stratified by calf age and assigned randomly to one of two treatments: control (no supplement) or supplemented. Supplemented calves received 0.9 kg of a 49% soy hulls, 44% wheat middlings, 6% molasses, and 1% limestone supplement (DM basis) daily. All calves were cannulated in the rumen and duodenum and given ad libitum access to chopped brome hay (Bromus inermus L; 7.43% CP, 40.96% ADF, and 63.99% NDF; DM basis). Supplementation was initiated on May 1 (88 +/- 10.3 d calf age). Three sampling periods were conducted throughout the study (June 14 to 25, July 5 to 16, and August 9 to 20). Supplement and forage were offered at 0800 daily. Total, hay, and milk OM intakes of nursing calves were not affected by supplementation (2,014 vs. 2,328 +/- 288.8, 1,486 vs. 1,029 +/- 3,06.9, and 528 vs. 575 +/- 87.0 g/d, respectively). Milk OM intake was less (P < 0.09) in August than in June and July (635, 691, and 345 +/- 110.6 g/d for June, July, and August, respectively). A supplementation x month interaction occurred (P < 0.10) for total-tract OM digestion. Supplementation did not affect (P > 0.40) total-tract OM digestibility during June and August; however, during July, total-tract OM digestibility was lower (P = 0.03) for the control calves. Ruminal ammonia concentration, total VFA, and butyrate molar proportion increased (P < 0.05), whereas acetate proportion decreased (P = 0.01) in supplemented calves. Microbial efficiency was not influenced by supplementation (11.8 vs. 12.0 g/kg of OM truly fermented for control and supplemented calves, respectively). These data indicate that fiber-based supplements can be used as creep feed without negative effects on OM intake, total-tract OM digestibility, and ruminal fermentation characteristics in nursing beef calves.     

Effect of field pea replacement level on intake and digestion in beef steers fed by-product-based medium-concentrate diets

Four ruminally and duodenally cannulated steers (703.4 +/- 41 kg initial BW) were used in a 4 x 4 Latin square to evaluate the effects of field pea inclusion level on intake and site of digestion in beef steers fed medium-concentrate diets. Steers were offered feed ad libitum at 0700 and 1900 daily and were allowed free access to water. Diets consisted of 45% grass hay and 55% by-products based concentrate mixture and were formulated to contain a minimum of 12% CP (DM basis). Treatments consisted of (DM basis) 1) control, no pea; 2) 15% pea; 3) 30% pea; and 4) 45% pea in the total diet, with pea replacing wheat middlings, soybean hulls, and barley malt sprouts in the concentrate mixture. Experimental periods consisted of a 9-d dietary adjustment period followed by a 5-d collection period. Grass hay was incubated in situ, beginning on d 10, for 0, 2, 5, 9, 14, 24, 36, 72, and 98 h; and field pea and soybean hulls for 0, 2, 5, 9, 14, 24, 36, 48, and 72 h. Total DMI (15.0, 13.5, 14.1, 13.5 +/- 0.65 kg/d) and OM intake (13.4, 12.0, 12.6, 12.0 +/- 0.58 kg/d) decreased linearly (P = 0.10) with field pea inclusion. Apparent ruminal (17.5, 12.0, 0.6, 6.5 +/- 4.31%) and true ruminal CP digestibility (53.5, 48.7, 37.8, 46.2 +/- 3.83) decreased linearly (P < 0.10) with increasing field pea. Neutral detergent fiber intake (8.9, 7.9, 7.8, 7.0 +/- 0.3 kg/d) and fecal NDF output (3.1, 2.9, 2.6, 2.3 +/- 0.2 k/d) decreased linearly (P < 0.03) with increasing field pea. No effects were observed for microbial efficiency or total-tract digestibility of OM, CP, NDF, and ADF (P > or = 0.16). In situ DM and NDF disappearance rates of grass hay and soybean hulls decreased linearly (P < 0.05) with increasing field pea. Field pea in situ DM disappearance rate responded quadratically (P < 0.01; 5.9, 8.4, 5.5, and 4.9 +/- 0.52%/h, for 0, 15, 30, and 45% field pea level, respectively). Rate of in situ CP disappearance of grass hay decreased linearly (P < 0.01) with increasing field pea level. Field pea is a suitable ingredient for beef cattle consuming medium-concentrate diets, and the inclusion of up to 45% pea in by-products-based medium-concentrate growing diets decreased DMI, increased dietary UIP, and did not alter OM, NDF, or ADF digestibility.     

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.