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1.
Grass silages (n = 136) were selected from commercial farms across Northern Ireland according to their pH, ammonia nitrogen, DM, and predicted ME concentration. Each silage was offered to four sheep as a sole feed at maintenance feeding level to determine nutrient digestibility and urinary energy output. Dry matter concentration was determined as alcohol-corrected toluene DM and was subsequently used as the basis for all nutrient concentrations. The objectives were to use these data to examine relationships between nutritive value and nutrient concentration or fermentation characteristics in silages and then develop prediction equations for silage nutritive values using stepwise multiple regression techniques. The silages had a large range in quality (DM = 15.5 to 41.3%, ME = 7.7 to 12.9 MJ/kg of DM, pH = 3.5 to 5.5) and a relatively even distribution over the range. There was a positive relationship (P < 0.001) between silage GE and DE or ME concentration. Digestible OM in total DM (DOMD); ME/GE; and digestibility of DM, OM, and GE were positively related (P < 0.05) to CP, soluble CP, ether extract, lactic acid concentration, and lactic acid/ total VFA, whereas they were negatively related (P < 0.05) to ADF, NDF, lignin, individual VFA concentration, pH, and ammonia N/total N. Concentrations of DE and ME and digestibility of CP and NDF had similar relationships with those variables, although some relationships were not significant. Three sets of multiple prediction equations for DE and ME concentration; ME/ GE; DOMD; and digestibility of DM, OM, GE, CP, and NDF were therefore developed using three sets of predictors. The first set included GE, CP, soluble N/total N, DM, ash, NDF, lignin, lactic acid/total VFA, and ammonia N/total N; the second set excluded soluble N/ total N and lignin because they are not typically measured; the third set further excluded the fermentation data. The R2 values generally decreased with exclusion of predictors. The second and third sets of equations, except for NDF digestibility, were validated using the mean-square-prediction-error model and an independent grass silage data set published since 1977 (n = 17 [DM digestibility] to 28 [DOMD and OM digestibility]). The validation indicated that the equations developed in the present experiment could accurately predict DE and ME concentrations and DE/GE and ME/GE in grass silages.  相似文献   

2.
Wheat by-products are feedstuffs that vary in nutritional value, partly because of arabinoxylans that limit nutrient digestibility. Millrun is a byproduct from dry milling wheat into flour and contains varying amounts of the bran, middlings, screening, and shorts fractions. The digestible nutrient content of mill-run is not well known. Effects of xylanase supplementation (0 or 4,000 units/kg of diet) on energy, AA, P, and Ca digestibilities were studied in a wheat control diet and 5 diets containing 30% of a by-product (mill-run, middlings, shorts, screening, or bran) in a 2 x 6 factorial arrangement of treatments. The wheat control diet was formulated to contain 3.34 Mcal of DE/kg and 3.0 g of standardized ileal digestible Lys/Mcal of DE. Diets contained 0.4% chromic oxide. Each of 12 ileal-cannulated pigs (32.5 +/- 2.5 kg) was fed 6 or 7 of 12 diets at 3 times the DE requirement for maintenance in successive 10-d periods for 6 or 7 observations per diet. Feces and ileal digesta were each collected for 2 d. Xylanase tended to increase (P < 0.10) ileal energy digestibility by 2.2 percentage units and the DE content by 0.10 Mcal/kg of DM and increased (P < 0.05) ileal DM digestibility by 2.8 percentage units; a diet x xylanase interaction was not observed. Xylanase increased (P < 0.05) total tract energy and DM digestibilities and the DE content. A diet x xylanase interaction was observed; xylanase increased (P < 0.05) total tract energy digestibility of the millrun diet from 72.1 to 78.9%, DE content from 3.19 to 3.51 Mcal/kg of DM, and DM digestibility from 71.5 to 78.6%. Diet affected (P < 0.05) and xylanase improved (P < 0.05) digestibility and digestible contents of some AA in diets and by-products, including Lys, Thr, and Val. Xylanase increased (P < 0.05) Lys digestibility by 13.8, 5.0, 5.2, 6.0, and 14.1 percentage units in millrun, middlings, shorts, screening, and bran, respectively. Diet affected (P < 0.01) total tract P and Ca digestibilities. Xylanase increased (P < 0.05) digestible P and Ca contents. In summary, nutrient digestibility varies among wheat by-products. Millrun contained 2.65 Mcal of DE/kg of DM, which xylanase increased to 3.56 Mcal of DE/kg of DM. Xylanase improved nutrient digestibility and DE content in wheat by-products; and the extent of improvement depended on the by-product. Xylanase supplementation may maximize opportunities to include wheat byproducts in swine diets and ameliorate reductions in nutrient digestibility that may be associated with arabinoxylans.  相似文献   

3.
Determinations of digestibility of dry matter (DM), digestible energy (DE), and metabolizable energy (ME) in cassava chips with different levels of crude fiber (CF) were measured in growing pigs (20 kg) and finishing pigs (60 kg). The treatments were (1) cassava starch (0% CF), (2) peeled cassava chips (2.5% CF), (3) non-peeled washed cassava chips (3.9% CF), and (4) non-peeled and non-washed cassava chips (5.2% CF). In the growing pigs, peeled cassava chips, non-peeled washed cassava chips, and non-peeled and non-washed cassava chips had DM digestibility of 87.51%, 78.63%, and 73.89%, respectively. Their DE was 3.69, 3.49, and 3.32 Mcal/kg DM, respectively (DE of cassava starch is 3.90 Mcal/kg DM). ME was 3.54, 3.35, and 3.19 Mcal/kg DM, respectively (ME of cassava starch is 3.74 Mcal/kg DM). On the other hand, in the finishing pigs, the digestibility of DM was 89.13%, 80.63%, and 76.13%, respectively. Their DE was 3.72, 3.53, and 3.43 Mcal/kg DM, respectively (DE of cassava starch is 3.91 Mcal/kg DM). ME was 3.57, 3.38, and 3.29 Mcal/kg DM, respectively (ME of cassava starch is 3.75 Mcal/kg DM). These values increased with decreasing CF content, and the peeled cassava chips had the highest values (P < 0.01). These suggest that the digestibility values of DM, DE, and ME of cassava chips is inversely related to the CF content in cassava chips. It is recommended that cassava chips be peeled for better nutrition for growing and finishing pigs.  相似文献   

4.
This experiment was carried out to study the effect of a directly fed exogenous fibrolytic enzyme on intake and digestion of DM, OM, protein, NDF, ADF, and hemicellulose of alfalfa and ryegrass hay by sheep. Four diets were randomly assigned to four ruminally cannulated lambs using a 4 x 4 Latin square design, repeated in time, with a factorial arrangement (2 x 2) of diets: 1) alfalfa hay; 2) alfalfa hay + exogenous fibrolytic enzymes (enzyme); 3) ryegrass hay; and 4) ryegrass hay + enzyme. Lambs consumed more DM and OM from alfalfa than from ryegrass hay (P < 0.001). The ADF intake was not different between the hays, but NDF intake was lower for alfalfa (P < 0.001). For both hays, the enzyme increased intake of DM (P < 0.01), as well as OM and CP (P < 0.05); however, NDF and ADF intake were not changed. Alfalfa hay had higher apparent digestibility of DM, OM, and CP (P < 0.001), but lower digestibility for NDF, ADF, and hemicellulose. The enzyme increased apparent digestibility of CP, hemicellulose (P < 0.05), and NDF (P < 0.10) for alfalfa. Also, for both hays, the enzyme improved N balance because lambs retained more N (P < 0.05). The enzyme increased (P < 0.05) total VFA concentration (3 and 6 h) for both hays. Results from this trial indicate that directly fed exogenous fibrolytic enzymes may change ruminal fermentation, intake, and digestibility of forages with different nutritive value.  相似文献   

5.
Southern crabgrass (Digitaria ciliaris [Retz.] Koel.) is often an undesirable species in field and forage crops, but visual observations suggest that livestock prefer it to many other summer forages. The objectives of this study were to assess the nutritive value of crabgrass sampled weekly between July 11 and August 22, 2001 and then to determine ruminal in situ disappearance kinetics of N and neutral detergent insoluble N (NDIN) for these forages. A secondary objective was to compare these kinetic estimates for crabgrass with those of alfalfa (Medicago sativa L.), bermudagrass (Cynodon dactylon [L.] Pers.), and or-chardgrass (Dactylis glomerata L.) as control hays. All kinetic evaluations were conducted with 5 ruminally cannulated Gelbvieh x Angus x Brangus steers (383 +/- 22.7 kg). Concentrations of N for crabgrass decreased linearly (P < or = 0.002) across sampling dates for leaf, stem, and whole-plant tissues. Conversely, percentages of the total N pool within NDIN and ADIN fractions generally increased over sampling dates in mostly linear patterns. For crabgrass, the immediately soluble portion of the total N pool (fraction A; overall mean = 54.6% of N) was greater (P < 0.001) than for all control hays. Crabgrass exhibited a more rapid N disappearance rate (overall mean = 0.093/h; expressed as a proportion disappearing/h) than that of bermudagrass (0.046/h; P < 0.001), but the disappearance rate for alfalfa N (0.223/h) was considerably faster (P < 0.001) than for crabgrass. The effective ruminal disappearance of N was greater (P < 0.001) for crabgrass (overall mean = 85.4%) than for the alfalfa (83.3%), bermudagrass (72.3%), or orchardgrass (76.0%) control hays. For alfalfa, the ruminal disappearance rate of NDIN (0.150/h) was more rapid (P < 0.001) than for crabgrass (overall mean = 0.110/h); however, the disappearance rate for crabgrass was faster than that for bermudagrass (0.072/h; P < 0.001) or for orchardgrass (0.098/h; P = 0.010). Effective ruminal disappearance of NDIN was greater (P < 0.001) for crabgrass (overall mean = 72.0%) than for the bermudagrass (69.0%) or alfalfa hays (50.5%), but there was no difference (P = 0.865) between crabgrass and orchardgrass (72.1%). Although crabgrass forages exhibited concentrations of total N that were comparable with those of alfalfa and rates of ruminal N disappearance that were < 50% of those for the alfalfa hay control, improvements in N use efficiency relative to alfalfa are questionable because of the excessively large Fraction A for crabgrass.  相似文献   

6.
Spontaneous heating in stored alfalfa (Medicago sativa) has reduced forage quality and DM and N digestibility through microbial respiration and Maillard polymer formation. The impact of heating-degree-day (HDD) accumulation in stored bermudagrass (Cynodon dactylon [L.] Pers.) was evaluated for its effect on nutrient utilization by lambs. Twenty Rambouillet wether lambs (53.1 +/- 0.74 kg) were used in a completely randomized total collection experiment. The hays selected for this study had previously undergone spontaneous heating, producing either 5, 119, 201, 273, or 401 HDD (> 35 degrees C) during a 60-d storage period. Lambs were offered diets of these hays at 1.5% of BW. Dry matter intake did not differ (P = 0.59) among hays. Linear relationships were detected between HDD and apparent digestibilities of DM (y = 59.1 - 0.016x; P < 0.01; R2 = 0.37), OM (y = 59.3 - 0.017x; P < 0.01; R2 = 0.43), NDF (y = 66.4 - 0.012x; P = 0.01; R2 = 0.30), and hemicellulose (y = 74.0 - 0.012x; P = 0.02; R2 = 0.27). Similarly, significant regressions were observed for fecal N excretion (g/d; y = 4.70 + 0.004x; P < 0.01; R2 = 0.68), apparent N absorbed (g/d; y = 7.4 - 0.005x; P < 0.01; R2 = 0.50), apparent N absorption (%; y = 61.2 - 0.038x; P < 0.01; R2 = 0.71), apparent neutral detergent insoluble nitrogen digestibility (%; y = 85.8 - 0.026x; P = 0.01; R2 = 0.73), and apparent acid detergent insoluble nitrogen digestibility (%; y = 1.5 + 0.101x; P < 0.01; R2 = 0.62). Therefore, spontaneous heating during the storage of bermudagrass hay has a negative effect on dry matter and fiber digestion and nitrogen absorption by lambs.  相似文献   

7.
The objectives of this study were: 1) to determine if dietary protein reduction or oathull fiber inclusion would reduce urinary N excretion in grower pigs, 2) to determine if plasma urea could predict urinary N excretion among diets differing in protein and fiber content with an expected range in N excretion patterns, and 3) to determine the postprandial time point to sample blood for the best prediction. Three dietary protein concentrations (high, 19.7; medium, 16.9; low, 13.8%) and two fiber levels (high, 5.0; low, 3.6% crude fiber) were tested in a 3 x 2 factorial arrangement. Diets (wheat, barley, soybean meal; oathulls as fiber source) were formulated to 3.25 Mcal of digestible energy (DE)/kg and 2.2 g of digestible lysine/Mcal DE for low- and medium-protein diets, and 2.4 g/Mcal of DE for high-protein diets, and supplemented with lysine, methionine, tryptophan, threonine, isoleucine, or valine to meet an ideal amino acid profile. Pigs (32 +/- 3.4 kg; n = 42) were housed in metabolism crates for 19 d. On d 10 or 11, catheters were installed by cranial vena cava venipuncture. Daily feeding allowance was adjusted to 3x maintenance (3 x 110 kcal DE/kg body weight(0.75)), and was fed in two equal meals. Feces and urine were collected from d 15 to 19. Five blood samples were collected in 2-h intervals on d 16 and 19. Fecal, urinary, and total N excretion was reduced linearly with a reduction of dietary protein (P < 0.001); the reduction was greater for urinary (48%) and total N excretion (40%) than for fecal N excretion (23%). Similarly, the ratio of urinary to fecal N was reduced linearly with a reduction of dietary protein (P < 0.001). Retention of N (g/d) was reduced linearly, but N retention as a percentage of N intake was increased linearly with a reduction of dietary protein (P < 0.001). The addition of oathulls did not affect N excretion patterns and plasma urea (P > 0.10). Dietary treatments did not affect average daily gain or feed efficiency (P > 0.10). A dietary protein x time interaction affected plasma urea (P < 0.001). For medium- and high-protein diets, plasma urea increased postprandially, peaking 4 h after feeding, and then decreased toward preprandial levels (P < 0.05). Plasma urea did not alter postprandially for the low-protein diet (P > 0.10). Urinary N excretion (g/d) was predicted by 3.03 + 2.14 x plasma urea concentration (mmol/L) at 4 h after feeding (R2 = 0.66). Plasma urea concentration is indicative of daily urinary N excretion and reduction of dietary protein is effective to reduce total and urinary N excretion.  相似文献   

8.
The objective of these studies was to determine if dietary enzymes increase the digestibility of nutrients bound by nonstarch polysaccharides, such as arabinoxylans, or phytate in wheat millrun. Effects of millrun inclusion rates (20 or 40%), xylanase (0 or 4,375 units/kg of feed), and phytase (0 or 500 phytase units/kg of feed) on nutrient digestibility and growth performance were investigated in a 2 x 2 x 2 factorial arrangement with a wheat control diet (0% millrun). Diets were formulated to contain 3.34 Mcal of DE/kg and 3.0 g of true ileal digestible Lys/Mcal of DE and contained 0.4% chromic oxide. Each of 18 cannulated pigs (36.2 +/- 1.9 kg of BW) was fed 3 diets at 3x maintenance in successive 10-d periods for 6 observations per diet. Feces and ileal digesta were collected for 2 d. Ileal energy digestibility was reduced (P < 0.01) linearly by millrun and increased by xylanase (P < 0.01) and phytase (P < 0.05). Total tract energy digestibility was reduced linearly by millrun (P < 0.01) and increased by xylanase (P < 0.01). For 20% millrun, xylanase plus phytase improved DE content from 3.53 to 3.69 Mcal/kg of DM, a similar content to that of the wheat control diet (3.72 Mcal/kg of DM). Millrun linearly reduced (P < 0.01) ileal digestibility of Lys, Thr, Met, Ile, and Val. Xylanase improved (P < 0.05) ileal digestibility of Ile. Phytase improved ileal digestibility of Lys, Thr, Ile, and Val (P < 0.05). Millrun linearly reduced (P < 0.05) total tract P and Ca digestibility and retention. Phytase (P < 0.01) and xylanase (P < 0.05) improved total tract P digestibility, and phytase and xylanase tended to improve (P < 0.10) P retention. Phytase improved Ca digestibility (P < 0.05) and retention (P < 0.01). The 9 diets were also fed for 35 d to 8 individually housed pigs (36.2 +/- 3.4 kg of BW) per diet. Millrun reduced (P < 0.05) ADFI, ADG, and final BW. Xylanase increased (P < 0.05) G:F; phytase reduced (P < 0.05) ADFI; and xylanase tended to reduce (P = 0.07) ADFI. In summary, millrun reduced energy, AA, P, and Ca digestibility and growth performance compared with the wheat control diet. Xylanase and phytase improved energy, AA, and P digestibility, indicating that nonstarch polysaccharides and phytate limit nutrient digestibility in wheat byproducts. The improvement by xylanase of energy digestibility coincided with improved G:F but did not translate into improved ADG.  相似文献   

9.
The development of a metabolizable energy (ME) system for horses is described. Predictive equations for gross energy and digestible energy (DE) are revisited. The relationship between feed protein content and renal energy losses and the relationship between feed fibre content and methane energy losses were analysed in a literature review to develop predictive equations for ME. In horses, renal energy losses are much higher than losses by methane energy. Renal energy losses were correlated more strictly to protein intake than to digestible protein intake. The reason probably is that per gram of digestible crude protein energy losses are higher for roughage than for concentrates presumably because phenolic acids of forage cell walls contribute to higher urinary energy losses. However, digestibility of protein is lower in forages than in concentrates. The net result is a rather constant urinary energy loss of 0.008 MJ/g of crude protein in the feed. Methane losses in horses are smaller than in ruminants, presumably because of reductive acidogenesis in hind gut fermentation. Methane energy losses in equines are closely related to crude fibre intake. The mean methane energy losses amount to 0.002 MJ ME/g of crude fibre which can be used to correct for methane losses. Both corrections can be made for any predictive equation for DE. Metabolizable energy is then calculated as follows: ME MJ/kg = DE MJ/kg – 0.008 MJ/g crude protein – 0.002 MJ/g crude fibre. The equation of Zeyner and Kienzle (2002) to predict DE was adapted as mentioned above to predict ME: ME (MJ/kg dry matter) = ?3.54 + 0.0129 crude protein+0.0420 crude fat?0.0019 crude fibre+0.0185 N‐free extract (crude nutrients in g/kg dry matter).  相似文献   

10.
选用平均体重为(40±2)kg杜长大三元杂交去势公猪3头,按3×3的拉丁方进行试验设计,试验分3期,每期为7 d,采用全收粪法,研究不同蛋白质(CP)水平的氨基酸平衡日粮CP水平分别为14%、16%和18%)对氮、磷及能量代谢的影响。结果表明:不同蛋白质水平日粮处理间的氮表观消化率差异不显(著P>0.05),氮的沉积率以14%CP和16%CP组显著高于18%CP组(P<0.05),而14%CP和16%CP组之间无显著差异(P>0.05)。粪氮排出量14%CP日粮组显著低于16%CP和18%CP日粮组(P<0.05),16%CP日粮组和18%CP日粮组间无显著差异(P>0.05)。随着日粮蛋白质水平下降,生长猪的氮排出量、粪氮和尿氮均减少,总排泄氮中尿氮的比例较大,而粪氮则较少。不同蛋白质水平日粮对磷和能量的消化利用无显著影响(P>0.05)。  相似文献   

11.
Three studies were performed to examine the effect of starch and protein digestion rates on N retention in grower pigs. In Exp. 1, the glycemic index (GI) of corn, a malting barley, and a slow-rumen-degradable barley (SRD-barley) were measured using 6 barrows (BW = 18.0 ± 0.5 kg). The GI of malting barley was greater (P < 0.05) than that of SRD-barley (71.1 vs. 49.4), and the GI of both barley cultivars was less (P < 0.05) than that of corn (104.8). In Exp. 2, the standardized ileal digestibility of AA and DE content of the 3 ingredients were determined using 5 ileal-cannulated barrows (BW = 20.7 ± 2.3). The apparent total-tract energy digestibility values of corn (86.1%) and malting barley (85.7%) were greater (P < 0.05) than that of SRD-barley (82.3%). The standardized ileal digestibility of Lys was 94.0, 92.6, and 92.4% for corn, malting barley, and SRD-barley, respectively, and did not differ among grains. In Exp. 3, 6 diets were formulated to equal DE (3.40 Mcal/kg), standardized ileal digestibility of Lys (8.6 g/kg), starch (424.9 g/kg), and digestible CP (180.0 g/kg) using the values obtained in Exp. 2. Three GI [high (corn), medium (malting barley), and low (SRD-barley)] and 2 rates of protein digestion [rapid (soy protein hydrolysate) and slow (soy protein isolate)] were tested in a 3 × 2 factorial arrangement with 36 barrows (BW = 32.2 ± 2.5 kg). Pigs were fed 3.0 times the maintenance energy requirement daily in 2 meals for 2 wk and were housed in metabolic crates to collect feces and urine separately. At the end of the study, intestinal contents were collected from 4 equal-length segments of the small intestine. The percentage of unabsorbed CP in segment 1 relative to dietary CP was greater (P < 0.05) for the soy protein isolate diet than for the soy protein hydrolysate diet (170.3 vs. 116.5%). The percentages of unabsorbed starch in segments 1 and 2 were greater (P < 0.05) for the SRD-barley diet than for the malting barley or corn diet. Nitrogen intake and fecal N excretion were greater (P < 0.05) for pigs fed the malting barley and SRD-barley diets than for pigs fed the corn diet. Urinary N excretion was greater (P < 0.05) for pigs fed the SRD-barley diet than for pigs fed the corn or malting barley diet. Pigs fed slowly digestible starch (SRD-barley; 46.6%) had less (P < 0.05) net N retention than pigs fed corn or malting barley (54.7 and 54.1%, respectively). In conclusion, slowly digestible starch sources such as SRD-barley may not be suitable to support maximum protein deposition in restricted-fed grower pigs.  相似文献   

12.
Animals on pasture do not always have the opportunity for ad libitum consumption. Our objectives were to determine effects of intake level on digestibility of 12 grass hays, and to relate differences in intake and digestibility to proportions of leaf blade, leaf sheath and stem. In each of two periods, 24 wethers were offered one of 12 hays at three consecutive levels of feeding: (L1) ad libitum, allowing 15% refusal; (L2) restricted to 100% of hay consumed ad libitum by individual wether during L1; and (L3) 1.8% of BW on a DM basis. Hays offered included two sorghum-sudan, four barley, four oat and two pearl millet. Hays were similar in NDF concentration but differed in morphological composition Organic matter intake averaged 1.99 +/- .04, 1.79 +/- .04 and 1.52 +/- .01% of BW for L1, L2 and L3, respectively. Organic matter digestibilities averaged 71.8 +/- .55 72.4 +/- .60 and 72.3 +/- .65% for L1, L2 and L3, respectively. Intake SEM within hays were lower with restricted intakes (L3), whereas the opposite was observed for the SEM for digestibility. Forage morphological composition within feeding level influenced intake and digestibility by altering diet selection capabilities of wethers. Wethers did not consume equal NDF amounts, ranging form .95 to 1.47% of BW, because hays differed in morphological composition. Ash-free ADF and 72% sulfuric acid lignin were higher (P less than .01) in stem than in blade or sheath. In vivo digestibilities measured under restricted feeding conditions were related more closely (P less than .05) to in vitro estimates of digestibility than were digestibilities measured under ad libitum conditions (r = .72, .79 and .85 for L1, L2 and L3, respectively). This study demonstrates that variation in morphological characteristics of forages may account for part of the difference in voluntary intake of forages of similar chemical composition. New knowledge in this area will be valuable in developing improved forage quality prediction procedures.  相似文献   

13.
Two experiments were conducted to determine if ractopamine hydrochloride (RAC) could improve nutrient utilization and decrease water utilization, thus reducing the environmental footprint of hog operations. The tissue accretion experiment used comparative slaughter involving 120 barrows (95 ± 3 kg of BW), including 12 assigned to an initial slaughter group; the remaining pigs were slaughtered at 108 or 120 kg. Growth performance and nutrient retention were determined. The 15-d metabolism experiment consisted of 54 pigs (95 ± 3 kg of BW). Growth performance, feed and water intake, and urine and fecal output were measured. The metabolism experiment used 9 dietary treatments arranged as a 3 × 3 factorial: 3 quantities of RAC (0, 5, and 10 mg/kg) and 3 standardized ileal digestible-Lys:DE ratios (1.73, 2.14, and 2.63 g/Mcal of DE). The tissue accretion study was designed as a 3 × 3 × 2 factorial arrangement of treatments using the same 9 dietary treatments to include slaughter BW (108 and 120 kg of BW) as an additional factor. In the tissue accretion experiment, RAC had no effect on ADG, ADFI, or G:F (P>0.10). With increased Lys, G:F improved (P=0.029), but not ADG or ADFI (P>0.10). Protein deposition rates increased numerically (P=0.11); water deposition rates increased (P=0.050), whereas lipid deposition tended to decrease with RAC inclusion (P=0.055). With greater RAC and Lys, the pigs had improved ADG (P=0.002) and G:F (P<0.001) in the metabolism experiment. Daily water intake (P=0.017.) and water output (P=0.033) decreased with RAC inclusion. Lysine inclusion did not alter the water balance (P>0.10). Urinary N excretion (P<0.001), total N excretion (P=0.003), and the urine N:fecal N ratio (P<0.001) decreased with the addition of RAC; fecal N (P=0.008) increased with RAC inclusion. Retention of N improved with addition of RAC to the diet (P=0.003). With greater dietary Lys, fecal N was reduced (P<0.001). The pigs fed the 2.14 g of Lys/Mcal tended to have the least urinary N (P = 0.069) and total N excretion (P=0.086) and to have the greatest N retention (P=0.086) and urinary N:fecal N ratio (P=0.009). A RAC × Lys interaction was observed for N digestibility (P=0.001), excretion (P=0.001), and retention (P=0.002) and for fecal (P=0.001) and urinary N (P=0.036). By improving N and water utilization in finishing pigs, RAC-containing diets supplemented with sufficient Lys can reduce N excretion into the environment from swine facilities.  相似文献   

14.
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   

15.
我国奶牛饲料产奶净能值测算方法的研究   总被引：1，自引：0，他引：1  
本文将国内有关的奶牛消化代谢试验和单一饲料消化率试验材料进行整理和统计分析,制定出适合我国实际情况的根据饲料可消化能推算饲料产奶净能的回归公式,完善了我国的奶牛饲养标准。  相似文献   

16.
Two experiments were conducted to investigate the relationships between amino acids and DE for pigs weighing 20 to 50 kg. In Exp. 1, there were three dietary lysine levels that were either adjusted (1.50, 2.35 and 3.20 g/Mcal DE) for five DE levels (3.00 to 4.00 Mcal/kg) or unadjusted (.45, .71 and .96% of the diet) for three DE levels (3.50 to 4.00 Mcal/kg). In Exp. 2, diets containing six lysine:DE ratios (1.90 to 3.90 g/Mcal) at two DE levels (3.25 and 3.75 Mcal/kg) were fed. Pigs were housed individually, and could eat and drink ad libitum. When pigs weighed 50 kg, their empty body composition was determined by the urea dilution technique in Exp. 1 and by prediction equations based on backfat in Exp. 2. For the adjusted diets in Exp. 1, protein deposition and protein deposition:DE intake increased (P less than .01) slightly as DE levels increased. These criteria decreased linearly (P less than .001), and fat deposition increased (P = .11) as DE increased when lysine:DE ratios were not maintained. As lysine levels increased, protein deposition and protein deposition: DE intake increased (P less than .001) in both the adjusted and unadjusted diets. In Exp. 2, there was no effect of DE on either the rate or efficiency of protein deposition. Both protein deposition and protein deposition:DE intake increased (P less than .001) and fat deposition decreased as lysine:DE ratios increased up to 3.00 g lysine/Mcal DE. Protein deposition: lysine intake decreased (P less than .01) progressively as the lysine:DE ratio increased. Regression analyses indicated the protein deposition increased up to 3.00 g lysine/Mcal DE. The results demonstrate the need to adjust lysine according to energy levels and indicate that the optimum ratio for protein deposition was approximately 3.00 g lysine/Mcal DE (or 49 g of balanced protein/Mcal DE).  相似文献   

17.
试验旨在研究粗蛋白质与消化能之比（CP∶DE）对3～5月龄中国荷斯坦犊牛生长性能及饲料效率的影响。选取30头70日龄断奶后正常过渡的中国荷斯坦犊牛,分为A、B、C 3组,每组10头,饲喂CP∶DE(g/Mcal) 分别为50.0∶1、 52.0∶1、54.9∶1的日粮,试验期90 d。A、B、C 3组间平均日增重（ADG）依次为0.83、0.80和0.81 kg/d,组间无显著差异。A、B、C 3组间饲料效率分别为4.29、4.24、3.96 kg/d,组间差异不显著,但有随着蛋白能量比升高而升高的趋势。3组间粗蛋白质和干物质的表观消化率随着日粮蛋白能量比增加而增加;干物质和有机物的表观消化率随着日龄的增加而降低;磷的表观消化率在3月龄后趋于稳定。血清尿素氮含量随着日粮蛋白能量比的升高而升高。综合平均日增重、饲料利用率、营养物质表观消化率等各方面的因素,在本试验条件下,蛋白能量比为50.0∶1的日粮就能满足3～5月龄平均日增重为0.8 kg/d的中国荷斯坦犊牛的生长需要。  相似文献   

18.
Two experiments were conducted to (1) determine net energy (NE) values of soybean meal (SBM), Napus canola meal (NCM), Juncea canola meal (JCM), field pea, and wheat millrun (WM) using indirect calorimetry, and (2) compare the determined NE values with the calculated NE values of the same feedstuffs based on a prediction equation. In experiment 1, six ileal-cannulated barrows (31 kg) were fed five diets in 5 × 6 Youden square to give six replicates per diet. Diets were cornstarch-based diets containing SBM, NCM, JCM, field pea, or WM. The SBM was included as a reference. In experiment 2, six ileal-cannulated barrows (70 kg) were fed a N-free diet for determining energy digestibility and NE values of test feedstuffs fed in experiment 1 by difference method. The NE values of test feedstuffs were also calculated from the digestible energy (DE) values and analyzed macronutrient content of the test feedstuffs. On dry matter (DM) basis, SBM, NCM, JCM, field pea, and WM contained 51%, 41%, 42%, 28%, and 18% crude protein; 1.52%, 2.95%, 2.36%, 1.33%, and 3.12% ether extract; 2.93%, 0.14%, 1.44%, 36.7%, and 28.7% starch; and 5.30%, 21.0%, 13.4%, 9.49%, and 16.1% acid detergent fiber, respectively. The determined NE value for SBM (2.29 Mcal/kg) did not differ from that of NCM (1.72 Mcal/kg DM) or JCM (2.14 Mcal/kg DM). The NCM and JCM did not differ in NE value. Also, the determined NE value did not differ between field pea (2.00 Mcal/kg) and WM (2.55 Mcal/kg). The calculated NE values for SBM (2.18 Mcal/kg DM), NCM (1.73 Mcal/kg DM), and JCM (1.86 Mcal/kg DM) did not differ from the corresponding determined NE values of the same feedstuffs. However, the calculated NE value for field pea (2.51 Mcal/kg DM) was greater (P = 0.004) than the determined NE value of field pea, whereas the calculated NE value for WM (2.27 Mcal/kg DM) tended to be lower (P = 0.054) than the determined NE value of WM. In conclusion, the NE value for SBM and canola meals can be predicted based on the DE value and the macronutrient composition of the same feedstuffs. However, the NE value for field pea and WM may not be predicted precisely based on the DE value and the macronutrient composition of the same feedstuffs.  相似文献   

19.
Two experiments were conducted to evaluate the comparative feeding value of dried shredded sugarbeets (DSSB; 0, 20, and 40% of diet DM) as a replacement for steam-flaked corn (SFC) in finishing diets for feedlot cattle. In Exp. 1, 60 calf-fed Holstein steers (476 ± 6.3 kg) were used in a 97-d finishing trial. Substitution of SFC with DSSB did not affect ADG or DMI (P > 0.20). Increasing DSSB decreased gain efficiency (ADG:DMI; linear effect, P = 0.04) and dietary NE (linear effect, P = 0.03). Given that SFC has a NE(m) value of 2.38 Mcal/kg, the replacement NE(m) and NE(g) values for DSSB were 1.94 and 1.29 Mcal/kg, respectively. There were no treatment effects (P > 0.20) on carcass characteristics. In Exp. 2, 6 cannulated Holstein steers (205 kg) were used in a replicated 3 × 3 Latin square design to evaluate treatment effects on digestion. Ruminal digestion of starch, NDF, and feed N were not affected (P > 0.10) by DSSB, although ruminal OM digestion tended to increase (linear effect, P < 0.08). Replacing SFC with DSSB decreased flow of starch to the small intestine, but it increased flow of microbial N (linear effect, P = 0.05). There were no treatment effects (P > 0.14) on postruminal digestion of OM, NDF, starch, or feed N or total tract digestion of OM, starch, and N. Substitution of DSSB increased (linear effect, P = 0.05) total tract NDF digestion and decreased (linear effect, P = 0.05) dietary DE (Mcal/kg). Given that SFC has a DE value of 4.19 Mcal/kg, the replacement DE value of DSSB was 3.68 Mcal/kg. There were no treatment effects (P > 0.12) on ruminal pH or total VFA; however, DSSB decreased propionate (linear effect, P = 0.05) and increased acetate (linear effect, P = 0.07), butyrate (linear effect, P = 0.05), valerate (linear effect, P = 0.04), and estimated methane production (linear effect, P = 0.05). We concluded that DSSB may replace SFC in finishing diets at levels of up to 40% without detrimental effects on ADG and carcass characteristics. The NE value of DSSB is 82% that of SFC (DM basis). Partial replacement of SFC with DSSB alters ruminal VFA patterns, increasing estimated methane energy loss and slightly decreasing the efficiency of DE utilization.  相似文献   

20.
Growing goats, 45 Alpine and 45 Nubian, were used in a 3 x 3 factorial arrangement to quantify the influence of dietary energy and protein levels on daily DM intake and nutrient utilization for growth. Goats had ad libitum access to complete mixed diets containing either 2.46, 2.77 or 3.05 Mcal/kg ME plus 11.2, 12.7 or 15.1% CP for 16 wk. Dry matter intake decreased curvilinearly as dietary ME density increased (P less than .001). Dry matter intake increased linearly (P less than .05) as dietary CP level increased during all growth intervals except wk 25 to 28 of age. Average daily gain was 115, 113 and 99 g/d for goats fed diets containing 2.46, 2.77 and 3.05 Mcal/kg ME, respectively. Average daily gain was 104, 106 and 117 g/d for goats fed diets with 11.2, 12.7 and 15.1% CP, respectively. Dry matter intake was higher (P less than .01) for Alpine than for Nubian goats, whereas ADG was similar between breeds. Intake of ME was 248, 260 and 198 kcal/(kg.75.d) for goats fed the low- medium- and high-energy diets, respectively. Intake of CP was 9.1, 10.7 and 13.2 g/(kg.75.d) for goats fed low-, medium- and high-protein diets, respectively. Average requirements for growth derived from regression analysis of all data points were 4.6 kcal ME and .26 g CP/g ADG. The prediction equation for intake of growing goats of 4 to 8 mo of age was: DMI, g/d = 1,749 - 496 DE, kcal/g + 18 live weight, kg + 3 ADG, g/d; r2 = .73 (Sy.x = 127, P less than .0001, n = 90). The requirement of ME for growth was 33% lower than the value recommended in 1981 by the National Research Council.  相似文献   

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