有机物进食量和外流速度对瘤胃VFA产生量及比例的影响

占日粮 70 %～ 80 %的碳水化合物和部分饲料蛋白质 ,在瘤胃中发酵产生挥发性脂肪酸(ＶＦＡ)、ＣＨ4、ＣＯ2 、ＡＴＰ等 ,为反刍家畜和瘤胃微生物维持和生长提供主要能量来源 ,因此评定ＶＦＡ中乙、丙、丁酸等比例及产生量 ,对于评定饲料营养价值及进一步提高反刍家畜能量转化效率具有重要意义。本试验旨在研究不同有机物进食量和外流速度对稻草 -玉米 -豆粕型日粮瘤胃发酵ＶＦＡ产生量及各挥发酸比例的影响。1　材料与方法1 1　试验动物和日粮　采用 3头体重在 50 0ｋｇ左右、安装有永久瘤胃瘘管的成年公牛。日粮采用ＡＲＣ(1 980 )肉牛饲…     

Studies on the ruminal concentration of total volatile fatty acids (VFA's) and their molar proportions in African cattle,sheep and goats

Few data comparing the utilization of feeds by African cattle, sheep and goats are available. The experiment, involving five adult animals with permanent rumen cannulae, supplies comparative data on fermentative digestion in these ruminants under tropical conditions.Two Red Sokoto (Maradi) goats, two West African dwarf sheep, and one White Fulani (Zebu) steer were first maintained on a basal ration of freshly chopped Cynodon nlemfuensis and Centrosema pubescens for 21 days, followed by the forage plus groundnut cake or urea concentrate supplements at 0, 10, 17 and 24% protein levels.Supplementation of the basal rations with the concentrates brought about increasing levels of total VFA's in the animals, tending to be higher in the steer than in the goats or sheep, with no appreciable differences for the individual VFA's and ruminal pH. It also resulted in a significant lowering of the acetic acid levels (P<0.05) with a corresponding increase of the propionic acid concentration in the rumen, giving the lowest molar % of acetic acid and the highest molar % of propionic acid with the 17% crude protein concentrate.While the increasing levels of the proteins or urea in the concentrate resulted in significant increases in the iso-butyric acid concentration (P<0.05) differences in the concentration of n-butyric acid were not significant (P>0.05). However, the basal ration produced neither iso-butyric acid nor n-valeric acid in the rumens of these animals. It was a noteworthy observation that n-valeric acid production (about 3 percent) occurred only with the 24 percent groundnut cake protein.     

The effect of delays in feeding colostrum and the relationship between immunoglobulin concentration in the serum of neonatal calves and their rates of growth

SUMMARY Eighty-five unsuckled newborn calves, were fed 1.5 L of colostrum of known IgG concentration at either 2, 4, 6 or 8 hours after birth with no additional colostrum feeding. Another group of 11 calves were left with their dam for 16 hours after birth, before separation. Blood samples were taken from all calves 24 hours after colostrum feeding or separation from the dam and serum Ig concentrations were measured by electrophoresis. There were no significant differences in mean serum Ig concentrations between calves fed at the different times after birth. Three of the 11 calves left to suckle were hypogamma-globulinaemic. Other calves in this group had higher serum Ig concentrations than the means of all other groups. All groups had mean serum Ig concentrations higher than the suggested minimum concentration required for adequate calf health. There were a number of calves that did not reach the suggested minimum serum concentration after feeding, but calf mortality was low and all calves were healthy apart from a slight scour for a few weeks after birth. There was no significant relationship between serum Ig concentration 24 to 48 hours after birth and either calf mortality or average growth rate over an 8- to 10-month period.     

不同有机物进食量和外流速度对瘤胃发酵及微生物蛋白合成效率的影响

采用2×2随机因子试验设计研究持续动态瘤胃模拟装置(RSI-Ⅱ)不同有机物进食量(OMI)(27．67g、36．74g、46．00g)和瘤胃外流速度(0．02/h、0．035/h、0．05/h)对稻草-玉米-豆粕型日粮瘤胃发酵及微生物蛋白合成效率的影响。结果表明,RSI内pH值不受有机物进食量和外流速度的影响;在低外流速度下各OMI组瘤胃内0～72h干物质、有机物、粗蛋白、NDF、ADF降解率均高于高外流速度(P＜0．05)。随着OMI的增加,同一外流速度下日粮可发酵有机物产生VFA量(TVFA/FOM,mmol/g)逐渐下降(P＜0．05);相同OMI组饲料降解氮转化为微生物氮的效率在外流速度为0．02h时显著高于高外流速度(P＜0．05)。     

Production of volatile fatty acids in the rumen of calves during dietary-microbial stimulation and early weaning

The contents of volatile fatty acids in the rumen fluid were studied in calves at an early (seven weeks of age) and traditional weaning term (nine weeks of age). Weaning at the age of seven weeks enabled to save 16.2 kg of milk replacer per calf; there was also a lower content of concentrates in the starter feed with a supplement of Amylastim. The health condition of the calves was good in both groups. The average daily weight gains for the period from the second to the ninth week of age were 0.550 kg in the early weaned calves and 0.690 kg in the calves weaned at a normal time. Early weaning had a positive influence on the development of rumen metabolism. Calves weaned at the age of seven weeks, compared with those weaned at the age of nine weeks, had much higher concentrations of VFA (p less than 0.05) in rumen fluid (at the age of seven weeks: 130.49 mmol per litre vs. 111.53 mmol per litre; at the age of eight weeks: 119.74 mmol per litre vs. 96.98 mmol per litre). Early weaned calves had the statistically significantly (p less than 0.05) higher proportions of propionic acid, butyric acid, i-butyric acid, and valeric acid. Later-weaned calves had the significantly higher (p less than 0.05) contents of acetic acid and i-valeric acid.     

体外法研究总挥发性脂肪酸和产气量与饲料营养成分的关系

本试验旨在通过测定青贮玉米、苜蓿、玉米秸、豆秸、羊草、稻草、专用青贮玉米秸7种粗饲料的总挥发性脂肪酸(TVFA)与产气量(GAS)及饲料营养成分[干物质(DM)、粗友分(ASH)、粗蛋白质(CP)和中性洗涤纤维(NDF)],研究三者之间的相关性.结果表明:不同时间点的TVFA与GAS及饲料营养成分之间的关系式为:TVFA=1.07×GAS-1.41×CP-0.90×NDF-6.80×NDS/CP-2.33x(NDS-ASH)/CP+113.70,R2=0.7431.本试验R2值较大,表明本试验所得的关系式具有更好的应用价值.     

异位酸与叶酸对犊牛生长性能、氮平衡和血液指标的影响

试验旨在研究日粮添加异位酸(branched-chain volatile fatty acids, BCVFA)与叶酸(folic acid, FA)对犊牛生长性能、氮平衡与血液代谢产物的影响。试验选用16头60日龄、体重(BW)(91±5.3) kg的中国荷斯坦奶公牛,进行为期80 d的2×2因子饲养试验。结果表明:BCVFA与FA对犊牛消化氮、沉积氮、沉积氮/采食氮和沉积氮/消化氮存在交互作用(P<0.05)。BCVFA与FA显著提高了犊牛干物质采食量、日增重和饲料效率(P<0.05)。采食氮、消化氮、沉积氮、沉积氮/采食氮和沉积氮/消化氮显著增加(P<0.05);总氮排泄量显著降低(P<0.05)。血液葡萄糖、总蛋白和白蛋白显著增加(P<0.05);尿素氮浓度显著降低(P<0.05)。综上可知,20 g/d BCVFA和0.1 mg/kg BW FA均能促进犊牛生长,提高日粮氮利用率。     

Influence of supplemental four- and five-carbon volatile fatty acids on forage intake and utilization by steers

Four ruminally and duodenally cannulated crossbred steers (avg wt 282 kg; trial 1) and 12 intact Hereford steers (avg wt 336 kg; trial 2) were used to evaluate the effects of supplemental four- and five-carbon volatile fatty acids (SFA) on intake and digestion of low-quality prairie grass hay (PH). Steers were fed PH at 1.8% body weight (trial 1) or free choice (trial 2) together with a 34% protein, urea-cottonseed meal supplement (365 g/d trial 1; 500 g/d trial 2) plus 0 or 30 g/d of SFA (Ca-salts of isoC4, C5, and isoC5 acids). Ruminal pH, ammonia-N and total volatile fatty acid concentrations were not influenced (P greater than .10) by SFA. Addition of SFA increased the molar proportions of isobutyric (.84 vs .11; P less than .05), isovaleric (1.01 vs .32; P less than .01), and valeric (.66 vs .47; P less than .07) acids but did not significantly alter the proportions of other acids. Apparent total tract organic matter digestion (51.9 vs 53.7%; P = .095) tended to decrease with SFA, while ruminal and total tract digestion of acid detergent fiber and N were not affected by SFA. Microbial N (MN) flow to the duodenum and efficiency of microbial crude protein (MCP) synthesis were similar for both treatments (66.7 vs 57.4 g MN/d and 29.8 vs 24.4 g MCP/100 g apparently fermented organic matter, respectively). In trial 2, total tract dry matter and acid detergent fiber digestion and voluntary intake were similar for both diets. Results suggest that intake and utilization of prairie hay was not limited by a ruminal deficiency of SFA.     

Effect of the addition of Enterolobium cyclocarpum pods and Gliricidia sepium forage to Brachiaria brizantha on dry matter degradation,volatile fatty acid concentration,and in vitro methane production

Tropical Animal Health and Production - The purpose of this study was to determine the in vitro fermentation and methane (CH4) production in the grass Brachiaria brizantha (B) alone or when mixed...     

Influence of vitamin E on organic matter fermentation,ruminal protein and fatty acid metabolism,protozoa concentrations and transfer of fatty acids

Vitamin E (Vit. E) is discussed to influence ruminal biohydrogenation. The objective of this study was to investigate the influence of a Vit. E supplementation on rumen fermentation characteristics, ruminal microbial protein synthesis as well as ruminal organic matter fermentation. Furthermore, we aimed to investigate the influence of Vit. E supplementation on short‐chain fatty acids (SCFA) and protozoa concentrations in the rumen and, in addition, on transfer rates of middle‐chain and long‐chain fatty acids into the duodenum in lactating dairy cows. Eight rumen and duodenum fistulated German Holstein cows were assigned to either a group receiving 2,327 IU/d Vit. E (138.6 IU/kg DM DL‐α‐tocopherylacetate; n = 4) or a control group (23.1 IU/kg DM; n = 4). Neither ruminal protein synthesis nor organic matter fermentation was influenced by treatment. Vit. E did not act on the concentrations of short‐chain fatty acids and protozoa in rumen fluid. Duodenal flow of C13:0 (1.3 versus 0.2 g/d, p = 0.014) and iso‐C14:0 (1.0 versus 0.5 g/d, p = 0.050) was higher in the Vit. E group. We observed a trend for higher duodenal flows for C12:0 (1.6 versus 0.9 g/d, p = 0.095) and anteiso‐C15:0 (12.2 versus 8.9 g/d, p = 0.084). Transfer rate of C12:0 tended to be higher in the Vit. E group (125.61 versus 73.96, p = 0.082). No other transfer rates were affected by treatment. Further studies are necessary to investigate the influence of Vit. E on rumen microbiota and their fatty acid production as well as on the impact of different doses of Vit. E supplementation on variables of protein synthesis efficiency.     

The relationship between total protein in serum, glutaraldehyde coagulation test and disease in feedlot calves

Serum from in all 249 calves were used to correlate the level of total protein (serum-Tp), gamma-globulin and the reaction of glutaraldehyde coagulation test (GCT) to each other. Further, of the 249 calves 219 were bled within two days after arrival to a feedlot and serum-Tp and GCT were related to subsequent diseases. The results revealed a close relationship between the three tests. Of the 219 calves 15% had a negative GCT (hypogammaglobulinemia) and 26% had a serum-Tp below 55 g/l. There was a significantly (p less than 0.001) higher disease frequency, 81%, in the GCT negative calves than in the GCT positive, 35%. Serum-Tp was significantly (p less than 0.001) higher in healthy compared to diseased calves. The mean values were 60.6, 57.2, 55.2 and 53.1 g/l for healthy calves, calves with respiratory disease, enteritis and both respiratory disease and enteritis respectively. Further, calves with a serum-Tp below 55 g/l developed disease earlier after arrival to the feedlot than those above this limit. It was concluded that both serum-Tp and GCT can be used in field investigation to identify calves predisposed to disease.     

Rumen fermentation with special reference to volatile fatty acid production during reproduction. 1. Methods and results of volatile fatty acid levels and production rates in vitro

The target of the investigations was to register part of the synthesis performance in the rumen of ewes during the complete reproduction cycle. With the help of in-vitro experiments with artificial rumen the concentration and production rates of volatile fatty acids in the rumen fluid were measured. From the experiments the measured data of fertility-accentuated crossbreeding (experiment 1) and crossbreeding (experiment 2) ewes were contrasted. The average concentrations of volatile fatty acids in ewes are 95.4 m mol/l in experiment 1 and 109.2 m mol/l in experiment 2 during the early stage gestation, 121.4 m mol/l in experiment 1 and 99.8 m mol/l in experiment 2 in the last stage stage of gestation, 129.6 m mol/l in experiment 1 and 112.8 m mol/l in experiment 2 during lactation and 106.6 m mol/l in experiment 1 and 112.9 m mol/l in experiment 2 during the dry period. The production rates of volatile fatty acids calculated form their concentration amount to 4.8 m mol/l X h in experiment 1 and 2.6 m mol/l X h in experiment 2 in the early stage of gestation, 3.5 m mol/l X h in experiment 1 and 3.1 m mol/l X h in experiment 2 in the last stage of gestation, 3.2 m mol/l X h in experiment 1 and 2.7 m mol/l X h in experiment 2 during lactation and 3.7 m mol/l X h in experiment 1 and 2.9 m mol/l X h in experiment 2 in the dry period. The correlation between the concentration and the production rate of volatile fatty acids is not significantly negative in either of the ewe experiments. The scattering of the individual values is wide so that the individual influence of the test animals as well as the influence of the in-vitro method used permit the conclusion that a significant statement on the influence of the genotype and the stage of reproduction on the production rates cannot be made.