摘要:

Protein and energy metabolism in boars of different breeds, 10 each of Hampshire, Duroc and Danish Landrace was measured in balance and respiration experiments by means of indirect calorimetry in an open‐air circulation system. Measurements were performed in four periods (Period I‐IV) covering the body weight range from 25 to 100 kg. In order to achieve maximum protein retention (RP) a daily intake of digestible protein > 12 g/kg0.75and metabolisable energy > 1100 kJ/kg0.75was assumed to be necessary. Protein retention of Danish Landrace boars was inferior to that of Hampshire and Duroc boars in Periods III and IV, and therefore, 55 measurements on Hampshire and Duroc boars fulfilling the chosen criteria for digested protein and ME intake were used for calculation of maximum protein retention, giving the following significant quadratic relationship: RP [g/d]= 11.43‐W0.75‐0.144‐W1.50(n = 55, RSD = 15.2, CV = 9.2%, R2= 0.851) with a summit of 227 g/d at 135 kg BW. In Period I, when BW was below 30 kg, 12 measurements fulfilled the chosen criterion for digested protein but not for ME, and these data were used comparatively. Protein retention of boars with a low ME intake in Period I was significantly below that of boars with a high ME intake (93 g/dvs.107 g/d; P = 0.02). In summary, the present data have shown that boars of high genetic potential have capacity for maximum protein retention of about 230 g/d, and that there was a significant quadratic relationship between protein retention and metabolic body weight, indicating that maximum protein retention was not reached until 135 kg BW. Differences in capacity for protein retention were recorded between boars of different breeds, with Duroc and Hampshire boars being superior to Danish Landrace boars. Additionally, the crucial importance of a sufficient ME supply early in the growth period was underscored by a lower protein accretion rate of boars given a daily ME supply below 1100 kJ ME/kg0.75at an approximate BW of 25 kg.

ISSN:0003-942X    

DOI:10.1080/17450399809381924

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

Energy metabolism and some performance parameters were investigated in laying hens of 3 different body weight‐genotypes: 6×7 (normal‐sized, crossbred from normal‐sized male and female lines, group 1), 47 x 38 (dwarf‐sized, breeding from a dwarf‐sized male line and a normal‐sized female line, group 2) and 44×47 (dwarf‐sized, breeding from dwarf‐sized male and female lines, group 3). Energy balance was measured by indirect calorimetry through C‐and N‐balances in 12 animals of each group during 10 consecutive days at production peak, within the period between the 27th and the 37th week of age. Hens were caged individually at 23°C environmental temperature and fedad libitumon a laying mash. The mean body weight in the dwarf‐sized groups 2 and 3 was 32% lower than in the normal‐sized group 1 during the energy balance period. The daily gross energy intake in group 2 and 3 was decreased by 33 and 34%, respectively. There were no significant differences in digestibility and metabolizability of gross energy between the groups. The energy requirements for maintenance [kJ ME/kg0.75d] derived from the energy balances were lower by 4% (P>0.05) and 14% (P<0.05) in the dwarf‐sized groups 2 and 3 as compared with the normal‐sized group 1, when equal coefficients of partial efficiency of metabolizable energy utilization for energy retention in body and eggs are assumed for the 3 body‐mass genotypes. There were no relevant differences in body composition at the end of the energy balance periods as well as in egg composition between the 3 experimental groups.

ISSN:0003-942X    

DOI:10.1080/17450399809381925

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

Effects of structural and non‐structural carbohydrates on the development of rumen fermentation and ruminai mucosa in calves were examined during the weaning period. Barley/soybean meal (SBM) group was fed a concentrate starting from 2 weeks of age, whereas alfalfa group received a mixture of concentrate and alfalfa hay in which the proportion of the latter was gradually increased from 20% to 70% between weeks 2 and 9 of age. The total volatile fatty acid concentration in rumen fluid of calves increased with age, but at 9 weeks there were no significant differences between the two diets (barley/SBM group 153 mmol/1, alfalfa group 150 mmol/1). Rumen papillae at 9 weeks of age, as compared to 6 weeks of age, were longer and fewer in number per square centimetre mucosa, with larger cut surface. This resulted in a higher surface of papillae per square centimetre mucosa at 9 weeks (barley/SBM group 286 mm2/cm2, alfalfa group 245 mm2/cm2) than at 6 weeks of age (barley/SBM group 217 mm2/cm2, alfalfa group 198 mm2/cm2). At 9 weeks of age, the pH (barley/SBM 5.0, alfalfa 5.7), the acetate to propionate ratio (barley/SBM 2.2, alfalfa 3.2) as well as the length of the papillae in the ventral ruminai sac (barley/SBM 1.96 mm, alfalfa 2.37 mm) were increased in the alfalfa group when compared to the barley/SBM group (P<0.1). In the former group, the proportion of butyrate revealed significantly increased values at 4 and 6 weeks of age. In animals of the barley/SBM group at 9 weeks of age, characteristic protrusions with proliferated thick epithelium occurred on the papillae and increased the surface for absorption. On the epithelium(Stratum corneum)desquamating cells with parakeratosis could be observed. In the alfalfa group the papillae of the ventral ruminai sac were longer, without protrusions. The morphotypes of the adhering rumen microflora differed between the groups. It can be concluded that feeding greater amounts of non‐structural carbohydrates increases the surface for absorption of the rumen epithelium in calves. The absence of hyperkeratosis and rumenitis in the barley/SBM group indicated that there is no reason to limit high starch diets in the early weaning period of calves.

ISSN:0003-942X    

DOI:10.1080/17450399809381926

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

Anin vitromodel using the model substance wheat bran as NSP source was developed to study the effects of NSP degrading enzymes (xylanase and β3‐glucanase) on NSP fractions. Thein vitromodel simulates the conditions (pH, dry matter, temperature and transit time) in the fore sections of the porcine gastrointestinal tract. By neglecting endogenous enzymes the sole effect of the added enzymes could be investigated.

ISSN:0003-942X    

DOI:10.1080/17450399809381927

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

An attempt has been made to find out if the organic matter digestibility of tropical feeds and fodders can be predicted from the results of anin vitrocellulase enzyme technique. Thein vivodigestibility coefficient of 27 tropical feeds and fodders was determined in wethers. The enzyme insoluble organic matter content of these feeds was determined using a cellulase enzyme technique. The indigestible OM (g/kg feed DM)in vivo(y) was plotted against enzyme insoluble organic matter (g/kg DM) (x). The equation is y = 60+0.817x, R2= 0.95; RSD = 32 g/kg DM. Equations for predicting DOM (g/kg DM) and digestibility of OM (%) are calculated. The testing of the equation on an independent data base of 40 individual feeds and fodders showed that the validity of the equation is fairly general.

ISSN:0003-942X    

DOI:10.1080/17450399809381928

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

Three different methods for the estimation ofin vitrofermentation kinetics are compared. The glass syringe, flow gasometer and pressure transducer methods were used for measurement of gas production. The rumen fluid from fistulated Merino sheep mixed with McDougall's buffer (1: 1) was used as an inoculum and added at an amount of 35 ml into the fermentation vessels containing 0.25 g of meadow hay. The total gas produced was recorded after 12, 24, 36, 48, 60, 72 and 96 h of incubation. Hay dry matter degradability was the same with all three methods and achieved 56.5 to 58.2%. Total volatile fatty acids were significantly lower with the pressure transducer method than with the syringe and flow gasometer method. Lower values of mol% of butyrate and valerate obtained with the flow gasometer and pressure transducer methods in comparison with the syringe were also observed. Total gas production estimated by the flow gasometer method was lower than that stated by the two other methods. With regard to precision of the used methods syringe method was the best followed by the pressure transducer and flow gasometer method. It can be concluded that in spite of some limitations the pressure transducer method used in this experiment can be regarded as suitable for total gas estimation inin vitrorumen fermentation experiments.

ISSN:0003-942X    

DOI:10.1080/17450399809381929

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

In three experiments (E1, E2, E3) maize silage of different physical structure and of different stage of maturity at harvest were fed to 24 (E1), 36 (E2) or 28 (E3) dairy cows. The cows were fed individually over an experimental period of five or six weeks. The maize silages had a mean DM content of 28% (E1), 32% (E2) or 36% (E3). At the stage of harvest, the stovers and the cobs had a mean DM content of <22% (E1, E2) or 27% (E3), 40% (E1), 46% (E2) or 57% (E3), respectively. The maize was harvested with a chopping length of 4 and 8 mm (E1, E3) and of 6 and 8 mm (E2), without corn cracking (E1) or with and without corn cracking (E2, E3). The daily feed ration consisted ofad libitumoffered maize silage, 1.7 kg DM hay, soya bean meal (E2, E3) and concentrate. The different chopping length of 4 mm, 6 mm or 8 mm had no effect on the maize silage intake in E1 and E2. In E3 the daily maize silage intake increased by about 1.2 kg DM per cow at a chopping length of 4 mm in comparison to 8 mm, whereas only the treatment with the combination of 4 mm chopping length and corn cracking showed a significant increase in DMI. The corn cracking improved the milk yield significantly (E2) or in a tendency (E3) at 2.0 kg (E2) or at 1.6 kg (E2), while the variation of chopping length had no effect on milk yield. The different physical structure did not influence the milk fat content with mean values of 4.65 % (E1), 4.15 % (E2) and 4.10% (E3), respectively. The milk protein content decreased in E2 feeding maize silage with a chopping length of 8 mm and corn cracking; but in El and E3 no effect was seen on protein content with mean values of 3.66 % (E1) or 3.51 % (E2).

ISSN:0003-942X    

DOI:10.1080/17450399809381930

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

Two bulls, each fitted with rumen and duodenal cannulas, received (in addition to a hay‐grain diet) twice daily an infusion of 200 g glycerol into the rumen over a period of six days. During this preliminaryin vivoinvestigation, the influence of a glycerol application on the rumen environment over a six‐day adaptation period was examined. Samples of rumen fluid were collected daily, two hours after glycerol infusion.

ISSN:0003-942X    

DOI:10.1080/17450399809381931

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

Investigations were conducted to assess the effect of duodenal infusions of oleic and linoleic acids both on milk composition and fatty acid patterns of milk fat. The investigations were carried out in two trials, I and II, each with 3 cows, fitted with a ruminai and a duodenal cannula. 56 g of oleic acid (Trial I) and 46 g linoleic acid (Trial II) were infused daily into the duodenum over a period of 7 days, while no application of fatty acids acted as a control in each case. An increase in milk fat content was observed in both trials whereas the content of protein and lactose in milk remained unaffected. In both trials the milk oleic acid and linoleic acid concentrations increased. In trial I C18: 1increased from 14.8 to 18.7%. In trial II C18: 1increased from 2.5to5.8% of total lipids. It was estimated that 84.8% of the infused C18: 1and 86.5% of C18: 1were transferred into milk fat.

ISSN:0003-942X    

DOI:10.1080/17450399809381932

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

Tierernährung. Leitfaden für Studium, Beratung und Praxis, von Manfred Kirchgeßner 10., neubearbeitete Auflage 1997, VerlagsUnionAgrar ISBN 3–7690–0549‐X, 582 Seiten, DM 60,‐

ISSN:0003-942X    

DOI:10.1080/17450399809381933

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor