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L Hoffmann

Publications and source records attributed to L Hoffmann.

At least 55 records · Page 3Linked to original sources
PubMed1994

[Proposal for the introduction of an energetic feed evaluation system for all domestic animals based on uniform parameters and principles. 2. Energetic feed evaluation for swine].

The energy availability from the feedstuffs and the energy requirement of animals are characterized by the metabolizable energy. The metabolizable energy of the feed (feedstuff, ration) is interpreted as potential energy. For comparative analyses within and between animals species with regard to the energetic feed value of single feedstuffs the parameter "relative fat retention effect" is introduced. The metabolizable energy of a ration is estimated in consideration of live weight and protein production (protein in body gain and milk). The energy requirement is calculated factorial--as a rule by the partial utilization of metabolizable energy for partial performances (e.g., kf, kp, kl) in connection with the level and kind of partial performance; km is not used in the system. The proposed system of energetic feed evaluation is available as "computer variant" as well as "manual variant". The computer programme is fitted first of all to application in research and teaching. (The complete documentation of the proposal for energetic feed evaluation for pigs including a diskette for using of the computer programme for scientific applications can be claimed in limited extend from the author.)

Animal Feed↗
PubMed1994

[Proposal for the introduction of an energy feed evaluation system based on unitary parameters and principles for all farm animals. 3. Energy feed evaluation for fowls].

The energy availability from the feedstuffs and the energy requirement of animals are characterized by the metabolizable energy. The metabolizable energy of the feed (feedstuff, ration) is interpreted as potential energy. For comparative analyses within and between animal species with regard to the energetic feed value of single feedstuffs the parameter "relative fat retention effect" is introduced. The metabolizable energy of a ration is estimated in consideration of live weight and protein production (protein in body gain and egg). The energy requirement is calculated factorial - as a rule by the partial utilization of metabolizable energy for partial performances (kf, kp, ko) in connection with the level and kind of partial performance; km is not used in the system. The proposed system of energetic feed evaluation is available as "computer variant" as well as "manual variant". The computer programme is fitted first of all to application in research and teaching. (The complete documentation of the proposal for energetic feed evaluation for fowls including a diskette for using of the computer programme for scientific application can be claimed in limited extend from the author.)

Animal Feed↗
PubMed1993

[The energetic utilization of L-fructose in rats].

The energetic utilization of L-fructose (LF) and D-fructose (DF) was investigated by means of indirect calorimetry in a difference trial on 9 male Wistar rats in the live weight range of 250 to 300 g. The daily rations in the two comparable periods with added fructose consisted of 10 g basal diet plus 2.7 g LF or 2.5 g DF. The digestibility and metabolizability of energy of the LF-ration were decreased by about 4 and 6%, resp., in comparison to the DF-ration. The efficiency of total utilization of energy (energy deposition/gross energy) amounted to (7 +/- 3)% (mean +/- SD) for the LF-ration and (10 +/- 3)% for the DF-ration. The lower digestibility of energy of the LF-ration was mainly due to a depression of apparent digestibility of crude protein, crude fat and crude fibre--obviously caused by increased microbial fermentation. With correction of the depression of digestibility the following values of energetic utilization resulted from the difference evaluation for LF and DF, resp.: digestibility (90 +/- 8)% and (100 +/- 6)%, metabolizability (85 +/- 8)% and (102 +/- 5)%, utilization of gross energy for energy deposition (69 +/- 11)% and (86 +/- 11)% and utilization of metabolizable energy (81 +/- 7)% and (84 +/- 11)%, resp.

Animals↗
PubMed1993

[Energy metabolism of chicks at low environmental temperatures].

The daily energy metabolism of growing chickens for meat production (origin T 82) fed ad libitum was measured from the 5th up to the 65th day of life at environmental temperatures decreasing in the course of development (25, 20, 15, 15, 15, 10, 10, 5 and 5 degrees C, resp.). Further in each period the heat production was measured through a wide range of temperatures (Maximum 40 degrees C to 5 degrees C in steps of 5 K) by 30-minute short time measurements. The mean live weight of the chickens was 75 g at the beginning of the experiment and 3416 g (male) or 2952 g (female) at the end of the experiment. The digestibility of energy and nutrients was independent of the stage of development. On average the total efficiency of utilization of metabolizable energy was 39.2 +/- 4.8% and the partial efficiency of utilization was 69.7 +/- 2.1%. 15-38% of the produced heat, caused by thermoregulation. The thermoneutral temperature decreased in the course of development from 35 to 18 degrees C and in the same way the thermoregulatory heat production decreased from 23 to 12 kJ/kg LW0.75.d.K. In the 2nd period the thermoregulatory heat production was extraordinarily high at an amount of 28 kJ/kg LW0.75.d.K.

Animal Feed↗
PubMed1993

[Comparative studies of the parameters of rumen fermentation and the digestibility of feed rations in cattle and sheep. 2. The digestibility of feed rations].

The results from 283 comparisons of digestibility in cattle (ox, cow, male and female young cattle) and sheep (adult wether) are presented. The crude protein content of the applied rations ranged from 90 to 340 and the crude fibre content from 80 to 430 g/kg DM. Within the range of rations with 200-350 g crude fibre per kg DM the differences between adult cattle and wether in the digestibility of energy and organic matter don't exceed 1%-unit (mean -0.5 +/- 2.5), that of crude protein is 5%-units lower in adult cattle than in adult wether. In young cattle digestibility is altogether lower than in wether; in young cattle with 120 to 200 kg live weight 4 to 6 and in more developed cattle 3 to 4 digestibility units for energy. In the metabolizability of the energy in comparison between adult wether and the different animal categories of cattle the difference don't exceed 1.5%-units. Relations between the live weight of cattle, the crude fibre of the rations as well as the nutrition level and the amount of difference of digestibility between cattle and sheep are considered.

Age Factors↗
PubMed1993

[The effect of the protein level of food on the energy maintenance requirement of growing rats on different feeding regimens].

Male Wistar rats were fed in the live weight range between 70 and 200 g in periods alternately for maintenance and weight gain (semi ad libitum). The diets contained 10, 40 and 70% crude protein, resp., the ambient temperature was 30 degrees C. In agreement with two previous experiments 2 different feed regimes were used. Whereas in the first growth phase (up to about 150 g live weight) the supply of protein was constant for each group, in the second growth phase the protein level was changed between the groups from one period to the other. The energy metabolism on the feeding level of maintenance was measured by indirect calorimetry. At both feeding regimes a dependence of energy maintenance requirement on the protein level of feeding was established. The differences in the maintenance requirement between the 10% and 70% protein level and in the first growth phase also between the 10% and 40% protein level corresponded on average to a growth phase the expected values of which result from the different efficiency of ATP synthesis in the oxidative degradation of nutrients. It follows that--in accordance with the previous findings--the feeding regime does not influence the ratio of energetic utilization of nutrients in the maintenance metabolism of growing rats under the experimental conditions used by us. Further the results of all our studies on the dependence of the energy maintenance requirement of growing rats on the nutrient composition are summarized. We conclude that a dependence on the protein-carbohydrate ratio of the diet according to the different efficiency of ATP synthesis in the protein and carbohydrate catabolism can be reproducibly established by our experimental methods only then, if more than 50% of the energy maintenance requirement are covered from protein energy.

Adenosine Triphosphate↗
PubMed1993

[Dependence of gross energy, digestive energy and metabolizable energy of feed and the energy disposition on the content of digestible nutrients in relation to starch and sugar. The progress of energetic feed evaluation. 1. Results from studies on swine].

On the basis of an analysis of energy metabolism measurements on adult pigs, fed on 92 ratios with very heterogeneous nutrient composition, the following prediction equations for gross energy (y1), digestible (y2) and metabolizable energy (y3) as well as for energy deposition effect of ratios (y) (kJ) are presented: y1 = 23.6z1 + 39.8z2 + 17.3z3 + 16.0z4 + 18.9z5 y2 = 23.6x1 + 39.8x2 + 17.3x3 + 16.0x4 + 17.2x5 y3 = 20.5x1 + 39.8x2 + 17.3x3 + 16.0x4 + 17.0x5 y = 11.0x1 + 34.0x2 + 12.7x3 + 11.6x4 + 5.0x7 + (12.0-0.14(80-x6))(x5-x7) [table: see text]

Animal Feed↗
PubMed1993

[Dependence of gross energy, digestible and metabolizable energy of feed and the energy onset on the content of digestible nutrients in regard to starch and sugar. A contribution to the further development of energetic feed evaluation. 2. Results from studies of cattle].

On the basis of an analysis of energy metabolism measurements on adult cattle (oxen), fed on 110 rations with very heterogeneous nutrient composition, the following prediction equations for gross energy (y1), digestible (y2) and metabolizable energy (y3) as well as for energy deposition effect of rations (y) (kJ) are presented: y1 = 23.6z1 + 34.0z2 + 17.3z3 + 16.0z4 + 19.1z5 y2 = 23.6x1 + 34.0x2 + 17.3x3 + 16.0x4 + 18.0x5 y3 = 17.3x1 + 34.0x2 + 15.9x3 + 15.1x4 + 15.4x5 y = (6.5x + 26.6x2 + 10.1x3 + 7.5x4 + 8.9x5) (-0.5574 + 0.04050x6 - 0.0002633x6(2)) [table: see text]

Animal Feed↗
PubMed1993

[Effect of the starch sources barley, corn and potatoes and their ration portions on nutrient digestibility and energy utilization in ruminants. 3. Energy utilization in cattle].

With investigations on the influence of different starch origins (barley, maize and raw potatoes) and different portions of the starch origins in the rations (50, 25 and 10% of the net energy fat, cattle (NEFr) content of the rations) on the energy utilization of rations a contribution was made to the development of the energetic feed evaluation within Rostock NEF-system. The experiments were carried out with fattened oxen using the methods of total metabolism technique and duodenal passage measurement by means of reentrant fistula. The nutrition levels amounted to 1.7 and 1.1 of energy maintenance requirement. The utilization of metabolizable energy for deposition of the 9 rations-including 3 variants of starch origins barley, maize and raw potatoes with parts in the rations of 50, 25 and 10%--was measured as 65, 61 and 59%, 61, 60 and 58% as well as 59, 61 and 55%. The energy maintenance requirement amounted to 526 kJ ME/kg LM 0.75.d. The gradations of energy utilization are caused by the connection between energy concentration and utilization of rations in ruminants. With comparable parts of the rations the different starch sources had no relevant influence on the energy utilization of the rations. Despite a wide range of starch plus water soluble carbohydrates (WSC) intake between 896 and 3426 g/animal.d no correlation between the kind of digestion (fermentative or enzymatic) of starch and WSC and the energy utilization of the rations was measurable, because the part of the ruminal digestion amounted to 86.0 and 97.2%. The result presented for the energy and nitrogen metabolism measurements are in good agreement with results of former experiments with 92 rations.

Animal Feed↗
PubMed1993

[The energy and nitrogen metabolism of pregnant and lactating sows and suckling piglets. 1. Experimental plan and results concerning the live weight development of pregnant, non-pregnant and lactating sows and the reproductive performance during gestation and lactation].

The aim of the experiments was to work out new results for a factorial derivation of energy and protein requirement. The experiments were carried out according to a 3 x 3 factorial experimental plan with 3 variants of litter number (1, 2 and 4, age of sows) and 3 variants of energy supply (120, 100 and 80% of the norm of pregnancy, continued in lactation with 80, 100 and 120%). Methods of the indirect calorimetry and the slaughtering technique were used. The mean cumulative live weight changes of the sows for the 9 experimental variants amounted from 13.1 to 63.2 kg for the 115 days of pregnancy and from -17.0 to 6.8 kg for the first 26 days of lactation. The chosen variation of energy supply of pregnant and lactating sows had no relevant effect on the reproductive performances, measured by litter size, weight of conception products, litter weight at birth and the quantity of milk per sow and day respectively. In comparison with the sows of litter number 1 the sows of litter number 2 and 4 had higher litter weights at birth and higher milk quantities.

Amino Acids↗
PubMed1993

[The energy and nitrogen metabolism of pregnant and lactating sows and suckling piglets. 2. Chemical composition and energy content of the animal bodies of pregnant, non-pregnant and lactating sows].

The influence of litter number (1, 2 and 4, age of sows) as well as gestation and lactation stage of sows on the chemical composition and on the quantities of protein and fat of their bodies was investigated. The slaughter of 46 pregnant, 18 non-pregnant and 17 lactating sows were carried out at the 1st, 56th, 84th, 98th, 105th and 113th day of gestation, 113th day of experiment (non-pregnant sows) and 26th day of lactation. The results were related to the sows' energy supply (120, 100 and 80%) with equal supply of protein, vitamins and minerals. Within the tested litter numbers the chemical composition of the bodies was nearly constant during the whole time of gestation and lactation. A good agreement existed for the chemical composition of the sows' bodies of litter number 1 and 2. In comparison to them the bodies of litter number 4 contained more protein and less fat per kg dry matter. The quantities of body protein and fat increased in the gestation and decreased in the lactation period, in each case the quantities of fat exceeded than the quantities of protein. The quantities of body protein increased with higher litter number. The quantities of body fat increased from litter number 1 to 2 and were nearly equal in the sows of litter numbers 1 and 4. Within one litter number the amounts of body protein and fat attained the same level in pregnant, non-pregnant and lactating sows.

Animals↗
PubMed1993

Investigations on the influence of Clenbuterol and recombinant porcine somatotropin on nitrogen and energy metabolism in growing pigs.

The effect of Clenbuterol and recombinant porcine Somatotropin (rpST) on the N and energy metabolism was tested by means of the respiration trial technique and compared with a control. In one experiment Clenbuterol was given per os on the nutrition level of three times energy maintenance requirement and in two experiments on the nutrition level 3.2 and 2.4 times energy maintenance requirement, rpST was injected s.c. The live weight gain of the treated animals was 9% (Clenbuterol), 18 and 24% (rpST) higher than that of the controls, protein energy deposition was 21% (Clenbuterol), 45 and 46% (rpST) higher and fat energy deposition was 14% (Clenbuterol), 33 and 37% (rpST) lower than that of the controls.

Aging↗
PubMed1993

[Energy and nitrogen metabolism of pregnant and lactating sows and suckling piglets. 3. Chemical composition and energy content of the animal body fractions as well as portions of the animal body fractions of empty body of nonpregnant, pregnant and lactating sows].

The study is based on the results obtained from the slaughter of 5 sows on the first day of pregnancy and the first day of the experiment respectively (pregnant and non-pregnant sows resp.), of 43 pregnant sows on the 56th, 84th, 98th, 105th and 113rd day of gestation as well as 17 lactating sows on the 26th day of lactation. The animal bodies of pregnant sows were divided in 15 fractions and those of non-pregnant and lactating sows in 12 fractions. The investigations were carried out with 3 x 3 variants of litter number (1, 2, 4) and energy supply (120, 100, 80% of requirement recommendation). The chemical composition and the energy content of the animal body fractions as well as their relative portions of the empty body were largely constant during the course of gestation with the exception of the reproductive organs and the conception products. The physiological stage of lactation connected with limited mobilization of body reserves resulted in a reduction in fat content of some body fractions as well as a limited increase of the portions of body organs contrary to the portions of body tissues of the empty body. In comparison with sows of litter numbers 1 and 2 the sows of litter number 4 were characterized by higher portions of bones and meat, valuable parts as well as by smaller portions of depotfat and meat from head and belly of empty body. The raising of the energy supply of the pregnant sows increased the portion of the depotfat and decreased the portion of the meat, valuable parts of the empty body. The chemical composition of the reproductive organs and the conception products as well as the portions of these fractions of the empty body were influenced strongly from the course of the gestation and lactation resp. The portions of the reproductive organs and of the conception products are small (related to energy < or = 5.7 and < or = 2.6% resp.)

Abattoirs↗
PubMed1993

[Proposal for the introduction of a metabolizable energy feed evaluation system based on unitary parameters and principles for all farm animals. 1. Energy feed evaluation for cattle].

The energy availability from the feedstuffs and the energy requirement of animals are characterized by the metabolizable energy. The metabolizable energy of the feed (feedstuff, ration) is interpreted as potential energy. For comparative analyses within and between animals species with regard to the energetic feed value of single feedstuffs the parameter "relative fat retention effect" is introduced. The metabolizable energy of a ration is estimated in consideration of energy level, live weight and protein production (protein in body gain and milk). The energy requirement is calculated factorial--as a rule by the partial utilization of metabolizable energy for partial performances (e.g. kf, kp, kl) in connection with the level and kind of partial performance; km is not used in the system. The proposed system of energetic feed evaluation is available as "computer variant" as well as "manual variant". The computer programme is fitted first of all to application in research and teaching. (The complete documentation of the proposal for energetic feed evaluation for cattle including a discette for using of the computer programme for scientific applications can be claimed in limited extend from the author.).

Animal Feed↗
PubMed1992

[The energy metabolism of growing swine in a live weight range of 10-50 kg. 3. Energy maintenance requirement of growing swine].

Investigations into the energy maintenance requirement yielded the following results: For the energy maintenance requirement (EMR) in dependence on live weight (LW) using the relation EMR = aLWb from 13 experiments, an exponent of the live weight of 0.647 +/- 0.054 (0.57 to 0.73) was found out. Increasing the protein content in the feed from approximately 17 to approximately 45% in 6 experiments lowered the energy maintenance requirements about 14, 4, 6, 2, 6 and 12% respectively. The animals' development had no influence on the difference. The amount of the energy maintenance requirement varied greatly between the experiments. Exclusively in the experiments with barrows, a lowest value of 634 and a highest value of 931 kJ metabolizable energy per kg LW0.62.d was measured. On average of 19 comparisons the energy maintenance requirement derived from growth and maintenance periods by means of regression analysis was significant (alpha = 0.05), about 4% higher than the energy maintenance requirement measured on maintenance level directly.

Animal Feed↗
PubMed1992

[The energetic utilization of rations with molasses, dried sugar beets, apple pectin and lucerne leaves by adult swine].

The energetic utilization of 6 rations with molasses, dried sugar beets, apple pectin and lucerne leaves was measured in 8 adult pigs by means of the respiration test technique. The energy digestibility of the rations ranged from 74 to 88%, the partial utilization of the metabolizable energy from 66 to 78%. From the results with apple pectin a mean energy deposition value of 7.2 +/- 12.5 kJ/g digestible pectin was derived. Taking into consideration results from previous recorded experiments and the high standard deviation for estimation of the energetic feed value as deposition effect of digestible pectin, 5 kJ/g are proposed.

Animal Feed↗