不同产地豆粕和DDGS营养成分、瘤胃降解率及小肠消化率的分析测定

试验研究了不同产地(吉林、九三、林口)豆粕(SBM)和不同产地(集贤、牡丹江、肇东)玉米酒精糟(DDGS)营养成分、CP的瘤胃降解规律及RUP的小肠消化率。试验选用3头装有永久性瘤胃瘘管的干奶期中国荷斯坦奶牛,利用尼龙袋原位培养法研究不同产地豆粕和DDGS在奶牛瘤胃中CP的降解规律。每个尼龙袋每种饲料装5 g,在瘤胃中培养0、2、4、8、16、24和48 h。将每个尼龙袋每种饲料装75 g瘤胃培养16 h,瘤胃未降解残渣强饲给公鸡,从而测定豆粕和DDGS的IDP。吉林豆粕中的CP和SP含量最高,林口豆粕最低,而九三豆粕居中。林口豆粕中NDIP和ADIP含量为29.10%和2.52%,在三种豆粕中处于最高。三种DDGS的CP、NDIP和ADIP含量的变化趋势一致,均为肇东地区最高,其次为集贤、牡丹江。除了慢速降解部分(b)的降解速率(c)外,豆粕和DDGS的其它降解参数均差异不显著。九三豆粕IDP为73.37%,显著高于其它两种豆粕(P<0.05)。集贤DDGS的IDP显著高于牡丹江DDGS(P<0.05),而肇东DDGS居中。由此得出结论,除了营养指标受到产地影响外,豆粕和DDGS的瘤胃降解率和小肠消化率均不受产地影响。     

Evaluation of low-oligosaccharide, low-phytate whole soybeans and soybean meal in canine foods

Eight mature dogs (19.3 +/- 0.1 kg) were used in an experiment to compare the effects of feeding soybeans containing low concentrations of oligosaccharides and phytate on nutrient availability in complete foods fed to dogs. All foods were formulated to be isonitrogenous and contained low-oligosaccharide, low-phytate soybean meal (LLM); conventional soybean meal (SBM); low-oligosaccharide, low-phytate whole soybeans (LLB); or conventional whole soybeans (WSB) as the protein source. Daily DMI averaged 287 +/- 4 g/d. Fecal outputs were greatest for LLB and WSB, averaging 48.2 g DM/d. Small intestinal DM digestibility ranged from 80.9% (LLM) to 74.0% (LLB) but was unaffected by treatment. Large intestinal DM digestibility did not differ among treatments (P = 0.652). Total-tract DM digestibility was higher (P = 0.020) for LLM (87.0%) than for SBM (84.8%). No difference in total-tract DM digestibility was observed for the two WSB foods (average = 83.3%; P = 0.286). Nitrogen retention did not differ among foods containing LLM and SBM (1.2 g of N/d; P = 0.486) or LLB and WSB (0.9 g of N/d; P = 0.225). Small intestinal N digestibility did not differ among LLM- and SBM-containing foods (80.6%; P = 0.190) or LLB and WSB (69.3%; P = 0.640). Total-tract N digestibility did not differ among foods containing LLM and SBM (83.5%; P = 0.627) or LLB and WSB (76.8%; P = 0.968). Tryptophan digestibility was higher for SBM than for LLM (P = 0.039). Histidine and tryptophan digestibilities were higher in WSB compared with LLB (P = 0.049 and P < 0.001, respectively). No differences in nonessential AA digestibility were observed when comparing soy-based foods. The results of this study demonstrate that LLM, SBM, LLB, and WSB can be effective sources of protein for canine foods and have a high digestibility. Differences in small intestinal digestibility of tryptophan and histidine may require consideration when formulating diets using low-oligosaccharide, low-phytate soybeans or meal.     

Ruminal degradability of crude protein from different treated soybean meals in lactating cows

Ruminal crude protein (CP) degradability of four commercially available soybean meal (SBM) types--untoasted (U), toasted (T), heat-treated (H) and formaldehyde-treated (F)--was studied by the use of in sacco and in vivo techniques with lactating German Friesian cows cannulated in the rumen, duodenum and ileum. In two in sacco experiments three cows were fed a diet based either on grass hay plus ear-maize silage or on barley whole plant silage. Ruminal degradation rate of CP was estimated as percent nitrogen (N) disappearance from polyester bags incubated in the rumen for 2, 4, 6, 8, 12 and 24 h. Ruminal degradation rate of CP varied among the four SBM types as well as between the two basal diets. N disappearance from the bags after 12 h of incubation averaged 96, 67, 37, and 23% for the U, T, H, and F SBM types, respectively, in the cows fed the hay/ear-maize silage diet vs 99, 86, 58 and 41% for the four SBM types, respectively, in the cows fed the barley whole plant silage diet. In the in vivo experiment, four cows were fed diets based on meadow hay and ear-maize silage in a 4 x 4 Latin square design. The effect of SBM treatment on the flow rate of non-ammonia N (NAN) into the duodenum, and its relationship with the ruminal degradation rate of CP of the four SBM types, was studied. Formaldehyde treatment increased the amount of NAN entering the duodenum (P less than .05): 485 g cow-1 day-1 compared to 383, 418 and 428 g for U, T and H, respectively. Calculated ruminal CP degradabilities were 93, 75, 71 and 38% for SBM types U, T, H and F, respectively.     

反刍家畜常用饲料蛋白质和氨基酸瘤胃降解特性和小肠消化率评定研究

本试验探讨了常用饲料在瘤胃的降解特性及非降解饲料的小肠消化率,旨在为研究反刍动物的营养平衡和消化规律及科学配制日粮提供依据。试验选用3头装瘤胃瘘管和十二指肠瘘管的肉牛,采用尼龙袋法研究反刍动物常用饲料粗蛋白质和氨基酸瘤胃降解参数和表观小肠消化率。结果表明,在本试验中粗蛋白质降解率由低到高的顺序为:酒糟蛋白、黄玉米、羊草、玉米胚芽饼、菜粕、棉粕、豆粕、花生饼、啤酒糟、苜蓿、米糠、小麦麸;总氨基酸瘤胃降解率由低至高的顺序依次为:酒糟蛋白、黄玉米、羊草、玉米胚芽饼、菜粕、豆粕、棉粕、啤酒糟、花生饼、苜蓿、米糠、小麦麸。除花生饼、酒糟蛋白和黄玉米外,粗蛋白质和总氨基酸的有效降解率差异不显著(P>0.05)。粗蛋白质的表观小肠消化率由低至高的顺序依次为:苜蓿、羊草、米糠、小麦麸、啤酒糟、玉米胚芽饼、棉粕、菜粕、玉米、酒糟蛋白、花生饼、豆粕;总氨基酸的小肠消化率由低至高的顺序依次为:羊草、苜蓿、米糠、小麦麸、啤酒糟、玉米胚芽饼、菜粕、棉粕、花生饼、玉米、酒糟蛋白、豆粕。由此可见,不同的饲料瘤胃降解特性是不同的,并且为小肠提供的各种可吸收氨基酸潜力也是不同的。     

The effects of dry extrusion temperature of whole soybeans on digestion of protein and amino acids by steers

Five Holstein steers (450 kg) with cannulas in the rumen, proximal duodenum, and terminal ileum were used in a 5 x 5 Latin square design to study the effects of extrusion temperature on site of digestion of nitrogenous compounds in whole soybeans. The basal diet contained 50% corn silage, 24% alfalfa hay, 16.6% corn starch, 4.05% ground corn, 1% urea, and 3.4% soybean oil. Raw soybeans or soybeans extruded at 116, 138, or 160 degrees C (diets 116, 138, and 160, respectively) replaced the soybean oil and most of the corn starch in the test diets. Total N (g/d) reaching the duodenum was 232, 293, 285, 308, and 299 for the basal, raw, 116, 138, and 160 diets, respectively. No differences were observed between the raw and extruded soybeans (P = 0.81), or for the linear or quadratic effects of extrusion temperature (P = 0.56 and P = 0.45, respectively). Nonbacterial N (g/d) reaching the duodenum was 63.1, 104.6, 106.7, 101.9, and 113.9 for the same diets, respectively, and was not influenced by extrusion or extrusion temperature. Nitrogen disappearance from the small intestine (g/d) was 150 for the basal diet, 194 for the raw soybean diet, and 187,221, and 213 for the 116,138, and 160 degrees C extruded diets, respectively; no differences were observed between the raw and the extruded soybeans, or for diets containing soybeans extruded at different temperatures. Nitrogen disappearance (% of N entering) from the small intestine was lower (P < 0.05) for steers fed the basal diet than for steers fed the soybean-supplemented diets (64.1 vs 68.5%). No differences (P > 0.10) due to extrusion temperature were detected for flows of individual, essential AA, nonessential AA, and total AA at the duodenum. As extrusion temperatures increased, there were linear increases (P < 0.10) in disappearance (g/d) of all individual AA from the small intestine except for methionine and glycine. Essential, nonessential, and total AA disappearance from the small intestine were increased linearly (P < 0.10) with increasing extrusion temperature. Extrusion of soybeans can protect soy protein against extensive ruminal degradation without compromising intestinal digestibility.     

Amino acid profile of escaped feed protein after rumen incubation and their intestinal digestibility.

The crude protein content and amino acid profile of seven feedstuffs (linseed meal, maize gluten meal, rapeseed meal, rapeseed meal protected, soybean meal, fullfat soybean extruded and sunflower meal) were determined before and after ruminal incubation for 16 h in three bulls with large rumen cannulas. The intestinal disappearance of amino acids was measured using mobile bag technique. Ruminal incubation affected amino acid profile of all experimental feedstuffs. Crude protein degradation varied from 29.3% for maize gluten meal to 86.4% for rapeseed meal. A tendency towards increased disappearance was observed for glutamic acid, histidine, lysine and proline and decreased disappearance for branched-chain amino acids. The intestinal crude protein digestibility was higher than > 80%, except rapeseed meal (66.4%) and sunflower meal (77.8%). The least digestible individual amino acids were methionine and isoleucine in rapeseed meal, histidine and methionine in rapeseed meal protected and arginine in sunflower meal. In general, the lowest amino acid digestibilities were found in feedstuffs with the highest fibre content. The feedstuffs show that they have different potential for supplying of limiting amino acids. Of particular value are the feedstuffs with low crude protein degradability in the rumen and high intestinal digestibility of amino acids.     

Methodological impact of starch determination on starch content and ileal digestibility of starch in grain legumes for growing pigs

Background: Grain legumes represent a valuable energy source in pig diets due to their high starch content. The present study was conducted to determine the content and apparent ileal digestibility(AID) of starch in different grain legume cultivars for pigs by means of both a polarimetric and enzymatic method for starch determination.Methods: Three experiments were conducted with six barrows each which were fitted with ileal T-cannulas. In total, 18 diets including six different cultivars of faba beans(Vicia faba L.) and peas(Pisum sativum L.), five different cultivars of lupins(Lupinus luteus L., Lupinus angustifolius L.), and one diet with a soybean meal(SBM) were fed.Results: The starch content of faba beans and peas was greater(P 0.05) when determined polarimetrically than enzymatically(438 vs. 345 g/kg dry matter(DM) in faba beans and 509 vs. 390 g/kg DM in peas, respectively).Considerable lower starch contents were obtained in lupins and SBM, with 82 and 48 g/kg DM(analyzed polarimetrically) and 1.1 and 3 g/kg DM(analyzed enzymatically), respectively. Mean values for contents of neutral detergent fiber(NDF) and acid detergent fiber(ADF) in grain legumes ranged from 111 and 79 g/kg DM in peas to248 and 207 g/kg DM in lupins, respectively. Contents of condensed tannins in the colored flowered faba bean cultivars ranged from 2.1 to 7.4 g/kg DM. The AID of starch was greater(P 0.05) in pea than in faba bean cultivars,and using the polarimetric starch determination method resulted in greater(P 0.05) digestibility values than using enzymatic starch analysis(84 vs. 80% in faba beans and 86 vs. 83% in peas). Moreover, AID of starch differed(P 0.05)within pea cultivars and starch digestibility in faba beans decreased linearly(P 0.05) as the content of condensed tannins increased. However, there was no relationship between contents of NDF and ADF and AID of starch in pea and faba bean cultivars.Conclusion: Both contents and AID of starch in grain legumes can vary as influenced by the analytical method used for starch determination. Generally, starch digestibility is greater when measured by polarimetric rather than enzymatic methods.     

Lupin as a protein supplement for growing lambs

Whole lupins (Lupinus albus) were roasted with exit temperatures ranging from approximately 130 (moderate heat) to 175 degrees C (high heat). In situ N disappearance after 12 h of incubation in the rumen was 83% for raw lupins, 45% for lupins roasted at moderate temperatures, and 39% for lupins roasted at high temperatures. Lambs fed lupins roasted at moderate temperatures retained more N (P less than .01) than those fed soybean meal (SBM). However, growth rate and feed efficiency were similar among lambs fed diets containing SBM, raw lupins, or roasted lupins. Dehulled lupins commercially roasted at low, moderate, and high temperatures resulted in ruminal in situ N disappearances of 59, 47, and 43% for the respective temperatures. Dehulled lupins (Lupinus albus) were also roasted in a laboratory oven for 2, 4, and 6 h at 120, 140, and 160 degrees C. Simulation of roasting for 2 h had no effect (P greater than .10) on ruminal in situ N disappearance at any of the temperatures. In situ N disappearance was reduced (P less than .05) after roasting for 4 h at 160 degrees C, but acid detergent insoluble N was only moderately increased. Nitrogen retention in lambs fed raw, dehulled lupins was equal (P greater than .10) to that of lambs fed SBM. Whole lupins or dehulled lupins can replace SBM as the sole protein supplement for growing lambs. Although roasting lupins decreased ruminal in situ N disappearance, it had no effect on growth of lambs.     

Factors affecting disappearance of feedstuffs from bags suspended in the rumen

Four experiments were conducted to examine the effect of various factors on in situ digestion of feedstuffs in the rumen of Holstein cows. In Exp. 1, the effect of various days, animals and animal diets on in situ digestion was evaluated. Measured disappearance of dry matter (DM) and nitrogen (N) from soybean meal (SBM) suspended in dacron bags was lowest when the host animal was fed a high grain diet. No effect due to animals, day of incubation or period of experimentation was observed. The effect of bag porosity and substrate particle size on DM and N disappearance from bags was studied in Exp. 2. Rip-stop nylon, a material with small pores, appeared to decrease the influx of digesting agents into bags and limited efflux of digested residues from bags when compared with bags made from dacron polyester material. Disappearance of DM and N from SBM and distillers grains (DG) in rip-stop nylon bags was greater when these feedstuffs were in the pulverized form rather than in the commercially processed form. In Exp. 3, dacron and Acropore bags, with pore sizes of 52 and 5 microns, respectively, were used to examine DM and N disappearance, in the rumen of cows, from total mixed diets containing various dietary N sources. Lower DM and N disappearance from Acropore bags was observed for each of the diets regardless of time spent in the rumen; much of the difference was established within the first hour. The effect of formaldehyde treatment on degradation of amino acids from SBM suspended in dacron bags in the rumen for 16 h was studied in Exp. 4. Increased resistance of SBM amino acids to degradation in the rumen was observed as a result of formaldehyde treatment levels as low as .3% by weight. A possible increase in protection of lysine from degradation relative to other amino acids was also observed.     

Effects of increasing crude protein level on nitrogen retention and intestinal supply of amino acids in lambs fed diets based on alkaline hydrogen peroxide-treated wheat straw.

The effects of increasing dietary CP level on N retention (Exp. 1) and intestinal supply of amino acids (AA; Exp. 2) were studied in lambs fed diets based on alkaline hydrogen peroxide-treated wheat straw (AHPWS). Soybean meal (SBM) was substituted for corn to increase CP level in both experiments. In Exp. 1, an incomplete design for the two-way elimination of error was used to allot 24 ram lambs (mean BW = 25 kg) within breed to six CP levels (6, 8, 10, 12, 14, and 16% of DM). Neutral detergent fiber digestibility and N retention increased quadratically (P = .06 and P less than .01, respectively) with increasing CP level. Nitrogen retention, expressed as a percentage of N intake, was greatest for lambs fed 12% CP (20.7%) but was greatest for lambs fed 14% CP when expressed as grams per day (4.0 g/d). In Exp. 2, five multicannulated St. Croix lambs (34 kg) were used in a 5 x 5 Latin square design. Treatments were 8.5, 11, 13.5, 16, and 18.5% dietary CP. Chromic oxide was used as a digesta flow marker and purines were used as a bacterial marker. Protein level had no effect on extent of dietary CP degradation in the rumen (69 +/- 3.2%). True ruminal OM digestibility increased (P less than .01) linearly and ruminal fluid NH3 N concentration increased (P less than .01) quadratically with increasing CP level. Total, bacterial, and nonbacterial N and AA flows to the duodenum increased (P less than .05) linearly with increasing CP level. Duodenal AA profile (g/100 g total AA) was altered slightly. The essential AA valine, isoleucine, phenylalanine, lysine, and arginine increased (P less than .05) and methionine decreased (P less than .05) in proportion to other AA with increasing CP level. Flows of all essential AA increased with increasing CP level. Apparent small intestinal N and AA disappearance increased linearly (P less than .05) and apparent total tract N digestibility increased (P less than .01) quadratically with increasing CP level. These data are interpreted to indicate that maximal N retention and fiber digestibility in diets based on AHPWS are obtained at 12% CP, even though the intestinal supply of AA continues to increase with increasing CP level. Supplementation of diets based on AHPWS with an extensively degraded protein source (SBM) does not substantially alter the profile of AA entering the duodenum compared to the AA profile of bacterial protein.     

Variability of amino acid digestibility of lupin and pea grains in caecectomised laying hens

1. The objective of this study was to investigate the variations in amino acid (AA) digestibility of lupin and pea grains in caecectomised laying hens. The relationship between AA digestibility and chemical constituents of the grains was determined.

2. Twelve variants of lupins and peas were each added to a basal diet at a concentration of 300 g/kg, at the expense of maize starch. The lupin and pea variants were separately investigated in two subsequent trials. Each trial consisted of two 7 × 7 Latin squares, each comprising the basal diet and six diets with lupins or peas.

3. Fourteen caecectomised laying hens (LSL-classic) were individually housed in metabolism cages and 120 g/d of experimental diets were provided for eight days. During the last four days, excreta were collected quantitatively and feed intake was recorded. A regression approach was used to determine the AA digestibility of the lupin and pea variants.

4. Amino acid digestibility of the lupins and peas was high, although significant differences in AA digestibility among the lupins and peas were detected. The digestibility of lysine was in the range of 0.87–0.91 and 0.87–0.93 for lupins and peas, respectively. The digestibility of methionine in lupins and peas varied between 0.80–0.88 and 0.72–0.90. Variations in AA digestibility in peas were more pronounced than in lupins.

5. Significant correlations between chemical constituents of lupins, such as alkaloids, and AA digestibility were detected in some cases, without a consistent pattern. In peas, tannin concentration and the insoluble protein fraction were negatively correlated with digestibility of some AAs, but only when one colour flower variant was considered. Trypsin inhibitor activity in peas was negatively correlated with AA digestibility, particularly for the white flower variants.     

不同发酵时间对全混合日粮的瘤胃降解特性以及小肠消化率的影响

试验旨在研究发酵0、3、7、15、30 d的全混合日粮(TMR)对瘤胃降解特性以及小肠消化率的影响。选用3头体重为550 kg左右、安装有永久性瘤胃瘘管的荷斯坦奶牛,采用尼龙袋法和三步体外法测定发酵全混合日粮(FTMR)的干物质(DM)、粗蛋白质(CP)、中性洗涤纤维(NDF)的瘤胃降解率以及瘤胃未降解蛋白(RUP)的小肠消化率。结果表明:随着发酵时间的延长,FTMR饲料的DM含量显著降低(P<0.05);随着发酵时间的延长,显著提高FTMR的DM、CP、NDF的瘤胃降解率(P<0.05)和CP、NDF的快速降解部分(P <0.05);同时发酵显著降低RUP的小肠消化率(P <0.05)。综上可知,全混合日粮提高了DM、CP和NDF在瘤胃中的瘤胃降解率,15、30 d的FTMR各营养成分的瘤胃降解性较好;RUP的小肠消化率随发酵时间的延长开始逐渐降低,7d之后降低最为明显。因此,应控制好TMR的发酵时间,以便更有效地利用饲料资源。     

The effect of Lupinus albus seeds on digestibility,performance and gastrointestinal tract indices in pigs

The effect of soya bean meal (SBM) substitution in the diet with white lupine (WL) seeds on performances and some parameters of the digestive tract of pigs were studied. The digestibility experiment was performed on 30 pigs using difference method combined with marker method, where one group was offered basal diet and in diet of experimental groups 25% of the basal diet was substituted with SBM or WL meal. The growth experiment was conducted on 48 pigs of approximately 20 kg body weight. The animals from the control group were fed with diet containing SBM, whereas in the experimental groups 50% or 100% of SBM was substituted with WL seeds. At the end of the experiment, eight pigs from each group were euthanized, and digesta and tissues were sampled. The apparent total tract digestibility of crude protein and dry matter was higher (p < 0.05), but crude fibre and ether extract were lower (p < 0.05) in the WL seeds than in SBM. Substituting 50% of SBM in the control diet with WL seeds did not affect significantly pig performance. Total substitution of SBM with WL seeds impacted negatively pigs growth and feed intake (p < 0.05), but it did not affect the length of villi and crypt depth. It also significantly increased ileum digesta viscosity and ammonia concentration in the ileum and caecum digesta. In the ileal digesta of animals offered WL seeds, an increased (p < 0.05) total bacterial and Enterobacteriaceae numbers were found, whereas reduced number of yeast and mould was found in the caecal digesta. The substitution of 50% SBM with WL seeds in the growing pig diet did not affect pigs' results, but the total substitution significantly decreased the performance of pigs and affected intestinal ecology.     

6种常用饲料原料在肉牛瘤胃内降解规律的研究

选用3头体重相近的安装有永久性瘤胃瘘管的科尔沁肉牛,采用尼龙袋法测定玉米面、压片玉米、啤酒糟、玉米酒糟、蚕豆和豌豆壳6种饲料原料在肉牛瘤胃内干物质(DM)、粗蛋白(CP)、淀粉的瘤胃降解率。结果显示:6种饲料原料的DM、CP的肉牛瘤胃有效降解率,压片玉米与玉米面显著高于蚕豆、豌豆壳、玉米酒糟和啤酒糟(P<0.05),压片玉米与玉米面差异不显著(P>0.05);淀粉的肉牛瘤胃有效降解率大小顺序依次为蚕豆、压片玉米、玉米面、豌豆壳、玉米酒糟和啤酒糟。试验表明,蚕豆和压片玉米、玉米面的瘤胃降解率较高,玉米酒糟与豌豆壳居中,啤酒糟相对较差。     

Characterization of dietary protein in Brassica carinata meal when used as a protein supplement for beef cattle consuming a forage-based diet

As a novel oilseed crop in Florida, Brassica carinata has the capacity of producing high-quality jet biofuel, with a protein-dense meal (~40% crude protein; CP) obtained as a by-product of oil extraction. Characterization of the meal protein is limited, yet necessary for formulation of beef cattle diets; therefore, the objective of this experiment was to determine ruminal and postruminal digestibility of protein from B. carinata. Eight ruminally cannulated Angus crossbred steers (473 ± 119 kg) were used in a duplicated 4 × 4 Latin square design, in which in situ ruminal and postruminal degradability of nutrients were evaluated. The three-step in vitro procedure was used to compare CP and amino acid (AA) degradation in B. carinata meal pellets (BCM) with that of cottonseed meal (CSM), dry distillers grains with solubles (DDGS), and soybean meal (SBM). In situ bags were incubated in the rumen for 0 to 96 hr, with the undegraded supplement remaining after 16 hr subjected to serial in vitro enzymatic solutions. Data were analyzed using the MIXED procedure of SAS. Ruminal rate of degradation of dry matter, organic matter, and CP was greatest (P ˂ 0.01; 10.9, 11.3, and 11.5 %/h, respectively) for SBM. Rumen degradable protein (RDP) content did not differ (P = 0.20; 47.8% and 55.1%, respectively) between CSM and DDGS, but was decreased (P ˂ 0.01) compared with SBM and BCM, which did not differ (P = 0.99; 72.3% and 71.8% RDP, respectively). Compared with DDGS, SBM had greater (P < 0.01) intestinal digestibility of rumen undegradable protein (RUP). Intestinally absorbable digestible protein (IADP) was greatest (P < 0.01) for CSM, with SBM and BCM having the least IADP. Total tract digestibility of CP (TTDP) was greater (P < 0.01) for SBM compared with CSM and DDGS. The contribution of RUP to intestinally absorbable AA was 7.2 and 3.1 g of lysine and methionine per kilogram of CP in BCM, respectively. The evaluation of B. carinata meal as protein supplemented for cattle consuming a forage-based diet resulted in 71.8% RDP and 97.1% TTDP, thus indicating its viability as a high-quality protein supplement for beef cattle.     

The effects of protein sources supplemented with urea-treated potato pulp (PP) silage and feeding levels of the PP silage-based concentrate on feed intake, digestibility and ruminal fermentation in beef steers

Six Japanese Black (Wagyu) steers (average initial weight 467 ± 45 kg) fitted with a ruminal cannula were used in a split‐plot design experiment comprising a 3 × 3 Latin square design (whole‐plot) and a randomized block design (subplot). The whole‐plot treatments were three different feeding levels of urea‐treated potato pulp (PP) silage‐based concentrate: 1.00%, 1.75% and 2.50% of body weight (BW) (on a dry matter (DM) basis). The subplot treatments consisted of the concentrate formulated to contain either soybean meal (SBM) as a rapidly rumen‐degraded protein source or corn gluten meal (CGM) as a slowly degraded protein source. Dry matter intake tended to be lower (P = 0.071) for CGM (8.9 kg/day) than for SBM (9.4 kg/day). Protein sources had no significant effect on digestibility and in situ degradation. Ruminal ammonia nitrogen (NH₃‐N) was lower (P = 0.033) for CGM (7.5 mg/dL) than for SBM (9.5 mg/dL). Protein sources did not affect ruminal pH and the total volatile fatty acids (VFA) concentrations. The molar proportions of ruminal acetate and valerate were higher (P = 0.032) for CGM than for SBM. The maximum daily intake of the PP silage‐based concentrate expressed as a percentage of BW was approximately 1.4% of BW. Dry matter intake was higher (P = 0.046) for steers fed at 1.0% of BW of the PP silage‐based concentrate than for steers fed at 1.75% or 2.5% of BW of the concentrate. The feeding levels of the PP silage‐based concentrate had no effect on DM and nutrients digestibility, except for crude protein (CP) digestibility. CP digestibility tended to be lower (P = 0.071) for steers fed at 1.75% of BW of the PP silage‐based concentrate than for steers fed at 1.0% or 2.5% of BW of the concentrate. The feeding levels of the PP silage‐based concentrate also did not affect the in situ degradation parameter of hay and PP silage. The feeding levels of the PP silage‐based concentrate did not affect ruminal pH, NH₃‐N and total VFA concentrations. The molar proportion of acetate was highest for steers fed at 1.0% of BW of the concentrate. In conclusion, in the urea‐treated PP silage‐based concentrate, CGM seems to be more effective than SBM for stabilizing the ruminal NH₃‐N concentration and to be advantageous for fiber digestion in the rumen. The feeding levels of the PP silage‐based concentrate did not change the amount of VFA production in the rumen and the DM digestibility.     

Nutritive value of ammoniated wheat straw fed to cattle

The effects of ammoniation of wheat straw on site and extent of digestion of nutrients by cattle and the nutritive value of the N added to the straw were studied using eight Hereford steers during three consecutive 21-d periods and analyzed in an incomplete block design with steers and periods as orthogonal blocking factors. The steers, approximately 30 mo old and weighing 360 +/- 24 kg, were cannulated in the rumen, duodenum and ileum. Diets consisted of untreated (US) or ammoniated (AS) wheat straw supplemented with a mineral-vitamin mixture. Steers fed US received four supplements in which the percentages of supplemental N from soybean meal (SBM) and urea were 0:100; 33:67; 67:33 or 100:0. Percentage of N and in vitro DM digestibility values were increased in US by the ammoniation process from .42 to 1.82 and 34.8 to 54.3, respectively. Total tract digestibility of OM consumed was similar among treatments, although total tract digestibility of dietary N was decreased by ammoniation. Ammoniation doubled (P less than .05) the synthesis of microbial N per unit of dietary OM truly fermented in the rumen. When SBM and urea were fed in combination they depressed (P less than .10) microbial N flow and synthesis of microbial N per unit of OM truly fermented more than each depressed flow and synthesis individually. The nutritive value of the increased N of AS was equivalent to between 67 and 100% of SBM N based on amounts (g/d) of non-ammonia N apparently digested in the small intestine.     

Effects of buffers on ruminal rate of passage and degradation of soybean meal in steers

Eight rumen-fistulated steers were randomly assigned to medium- and high-concentrate diets supplemented with 0, .75, 2.5 and 5% of either sodium bicarbonate or an artificial saliva salts mixture. Each animal was fed for 21 d at 75 g dry matter/kg body weight . 75. Rates of soybean meal (SBM) degradation were predicted by adjusting digestion rates in nylon bags with respective passage rates of chromium-mordanted SBM particles. Measures of rumen fermentation were made during the incubation period. Liquid dilution rate was determined with 51Cr-EDTA. The high-concentrate diet produced higher (P less than .05) liquid dilution rates than the medium-concentrate diet, but there were no differences in response to the two buffers (P greater than .05). The liquid dilution rates averaged across diets for 0, .75, 2.5 and 5% levels of buffer were 6.2, 6.3, 8.5 and 8.7%/h (SE = .03) and passage rates for SBM were 5.2, 5.2, 6.5 and 6.7%/h (SE = .025). The 2.5 and 5% levels of buffer increased the rate of disappearance of SBM from the nylon bags and buffers fed at these levels also increased rumen pH and NH3-N concentration. Rumen pH was correlated with N disappearance from the nylon bag (r = .903, P less than .05). Buffer levels did not affect degradation rates of SBM.     

The effect of different levels of soybean extract meal on the apparent digestibility of crude nutrients and amino acids in colostomized laying hens

Four colostomized laying hens per group were given a ration of barley and soya bean oil meal (SBM) with 12.5, 25.0 and 37.5% SBM resp. The crude protein intakes were 14.0, 17.7 and 21.4 g per animal and day. The lysine intake raised from 681 mg (group 1) to 1275 mg (group 3) per animal and day. The digestibility of dry matter and of the N-free extracts of the ration decreased with the rising SBM portion in the ration. The digestibility of crude protein remained constant. The investigated amino acids (Lys, His, Arg, Cys, Met) were higher digested in the 37.5% SBM ration than in the 12.5% SBM ration. The following digestibility values for SBM were found by means of the difference method: Dry matter 52.5%, crude protein 83.1%, crude fat 51.7%, crude fibre 5.5%, N-free extracts 50.6%. The level of the SBM did not influence the digestibility of the crude nutrients. The apparent digestibility of lysine from SBM depended on the level of intake and was found to be 82.3, 83.4 and 89.0%, resp. There were no differences in the digestibility of other amino acids.     

Feeding value of whole raw soya beans as a protein supplement for beef cattle consuming low‐quality forages

Experiments (Exp) I and II were conducted to compare raw whole soya beans (WSB), roasted (rWSB) or other protein sources as supplements of low‐quality forages fed ad libitum to beef cattle, upon DM intake (DMI), ruminal and blood parameters, and animal performance. Exp I: treatments for wheat straw fed to four ruminally cannulated steers were (i) Control‐WS: no supplement; (ii) WSB‐WS: whole soya beans; (iii) rWSB‐WS: roasted WSB; and (iv) SBM‐WS: soybean meal–wheat midds mixture; all fed at 1.4 kg DM/day. Exp II: 12 steers grazed deferred grain sorghum (DS) receiving these treatments: (i) Control‐DS: no supplement; (ii) WSB‐DS: 1.26 kg DM/day whole soya beans; and (iii) SFM‐DS: 1.35 kg DM/day of sunflower meal. In Exp I, WS DMI resulted 47, 52 and 41% greater for WSB‐WS, rWSB‐WS and SBM‐WS, respectively, than Control‐WS (p < .05). In Exp II, the DMI of DS was unaffected by supplementation; a substitution of DS by supplement was found for WSB‐DS (p < .05); however, total diet and digestible DMI increased with supplementation (p < .05). Rumen pH in Exp I remained unaffected by supplementation, but N‐NH₃ as well as blood urea‐N in Exp II increased (p < .05). In Exp II, average daily weight gains improved similarly with both supplements compared with Control‐DS. Additionally, feed‐to‐gain ratio decreased (p < .05), being lower for WSB‐DS (8.3) vs. SFM‐DS (9.9). Roasting effects of WSB as a supplement for low‐quality forages were not detected, and all protein sources increased total diet DMI and forage utilization. Only moderate cattle weight gains could be expected for unsupplemented DS.