Effect of imbalance between energy and nitrogen supplies on microbial protein synthesis and nitrogen metabolism in growing double-muscled Belgian Blue bulls

Six double-muscled Belgian Blue bulls (initial weight: 345 +/- 16 kg) with cannulas in the rumen and proximal duodenum were used in two juxtaposed 3 x 3 Latin squares to study the effect of a lack of synchronization between energy and N in the rumen on microbial protein synthesis and N metabolism by giving the same diet according to three different feeding patterns. The feed ingredients of the diet were separated into two groups supplying the same amount of fermentable OM (FOM), but characterized by different levels of ruminally degradable N (RDN). The first group primarily provided energy for the ruminal microbes (14.6 g of RDN/kg of FOM), and the second provided N (33.3 g of RDN/kg of FOM). These two groups were fed to the bulls simultaneously or alternately with the aim of creating three different time periods of imbalance (0, 12, or 24 h) between energy and N supplies in the rumen. The introduction of imbalance affected neither microbial-N flow at the duodenum (P = 0.65) nor efficiency of growth (P = 0.69), but decreased (P = 0.016) the NDF degradation in the rumen 12.2% for a 12-h period of imbalance. N retention was not affected by imbalance (P = 0.53) and reached 57.8, 58.5, and 54.7 g/d, respectively, for 0-, 12- and 24-h imbalance. It seems that the introduction of an imbalance of 12 or 24 h between energy and N supplies for the ruminal microbes by altering the feeding pattern of the same diet does not negatively influence microbial protein synthesis or N retention by the animal. Nitrogen recycling in the rumen plays a major role in regulating the amount ofruminally available N and allows for continuous synchronization of N- and energy-yielding substrates for the microorganisms in the rumen. Therefore, a lack of synchronization in the diet between the energy and N supplies for the ruminal microbes is not detrimental to their growth or for the animal as long as the nutrient supply is balanced on a 48-h basis. Thus, these dietary feeding patterns may be used under practical feeding conditions with minimal effect on the performance of ruminant animals.     

Effect of rumen-degradable protein balance deficit on voluntary intake, microbial protein synthesis, and nitrogen metabolism in growing double-muscled Belgian Blue bulls fed corn silage-based diet

Two trials were conducted to evaluate the effect of rumen-degradable protein balance (OEB) deficit on voluntary intake (trial 1), microbial protein synthesis, and N metabolism (trial 2) in growing double-muscled Belgian Blue bulls. In trial 1, six bulls (339 +/- 26 kg of initial BW) were used in a replicated 3 x 3 Latin square and received a diet of 60% corn silage and 40% concentrate with ad libitum intake (DM basis). Three concentrates were formulated by adding urea at the expense of barley to give similar dietary contents of intestinal digestible proteins, NE for fattening, and fermentable OM, but with different levels of OEB. Thus, 2 levels of OEB deficit (-23.7 and -9.2 g of OEB/kg of DM) were compared with a diet providing a slight OEB surplus (5.3 g of OEB/kg of DM). Voluntary DMI decreased linearly (P = 0.02) with decreasing rumen-degradable protein balance. This decrease in intake could explain the linear decrease in ADG observed when negative OEB diets were fed. In trial 2, six bulls (304 +/- 12 kg of initial BW) with cannulas in the rumen and proximal duodenum were used in a replicated 3 x 3 Latin square and fed diets similar to those used in trial 1 at an intake level of 85 g of DM/kg of BW(0.75). Diurnal variations of ruminal NH(3)-N and plasma urea-N concentrations were greatly influenced by the level of OEB in the diet. No differences in NDF and starch degradation in the rumen, microbial N flow at the duodenum, or efficiency of microbial protein synthesis in the rumen were noted among the levels of OEB in diets. The reductions of the OEB value from 5.3 g/kg of DM to -9.2 g/ kg of DM and -23.7 g/kg of DM were associated with reductions of 26.5 and 48.8% in urinary N output. Absolute amounts of N retained by the bulls increased significantly with the level of OEB in diets. Indeed, 51.4% of the incremental supply of N was excreted between -23.7 and -9.2 g of OEB/kg of DM diets, and 74.6% of the incremental supply of N was excreted between -9.2 and 5.3 g of OEB/kg of DM diets. Feeding diets characterized by an adequate intestinal digestible protein supply and a OEB close to -10 g of OEB/kg of DM could be a feeding strategy to reduce N losses from the farm with little effect on the animal performance and voluntary intake. Reduced OEB may reduce N excretion in the environment but may also result in decreased N retention.     

Effect of various levels of imbalance between energy and nitrogen release in the rumen on microbial protein synthesis and nitrogen metabolism in growing double-muscled Belgian Blue bulls fed a corn silage-based diet

Seven double-muscled Belgian Blue bulls (initial BW: 341 +/- 21 kg) with cannulas in the rumen and proximal duodenum were used in an incomplete replicated Latin square. The study examined the effect of imbalance between energy and N in the rumen on microbial protein synthesis and N metabolism by giving the same diet according to 3 different feeding patterns. The feed ingredients of the diet were separated into 2 groups supplying the same amount of fermentable OM (FOM) but characterized by different levels of ruminally degradable N (RDN). The first group primarily provided energy for the ruminal microbes (12.5 g of RDN/kg of FOM), whereas the second provided greater N (33.3 g of RDN/kg of FOM). These 2 groups were fed to the bulls in different combinations with the aim of creating 3 levels of imbalance (0, 20, and 40 g/ kg of DM) between energy and N supplies in the rumen. Imbalance was measured by the variation of the degradable protein balance (OEB value in the Dutch system) of the diet between the 2 meals each a day. Diurnal variations in ruminal NH3-N concentrations and plasma urea concentrations were greatly influenced by the feeding patterns of the diet. Introduction of imbalance affected neither microbial N flow at the duodenum (P = 0.97) nor efficiency of growth (P = 0.54). The feeding patterns of the diet had no negative impact on NDF degradation in the rumen (P = 0.33). Nitrogen retention was not affected by imbalance (P = 0.74) and reached 49.7, 52.0, and 51.3 g/d, respectively for 0, 20, and 40 g of OEB/kg of DM imbalance. It seems that introduction of an imbalance between energy and N supplies for the ruminal microbes by altering the feeding pattern of the same diet does not negatively influence the microbial activity in the rumen nor N retention of the animal. Nitrogen recycling in the rumen plays a major role in regulating the amount of ruminally available N and allows a continuous synchronization of N and energy-yielding substrates for the microorganisms in the rumen. Therefore, imbalance between dietary energy and N created over a 24-h interval was not detrimental to rumen microbial growth for the animal as long as the level of imbalance did not exceed 40 g of OEB/kg of DM. Thus, these feeding patterns of the diet can be used under practical feeding conditions with minimal impact on the performance of ruminant animals for meat production.     

Anatomical,physiological and biochemical differences between conventional and double-muscled cattle in the Belgian blue and white breed

Some morphological and physiological characteristics of the culard phenotype have been studied on ‘conventional’ and ‘double-muscled’ animals slaughtered at a constant weight of 83 kg (experiment I) or at a constant age of 1 year (experiment II). Muscle hypertrophy of the culard occurs at the expense of other organs (thymus, spleen,71 ) or tissues (fat, bones) which are relatively hypotrophied. Haematocrit appears to be significantly lower in double-muscled animals.On the contrary, plasma creatinine concentration is much higher in the culard (+60% at 4.5 months, +35% at 12 months). Therefore, plasma creatinine concentration may be a useful laboratory test to distinguish between these two bovine phenotypes. However, this excess in creatinine concentration cannot be accounted for by the muscular hypertrophy alone which amounts to some 20% in the ‘double-muscled’ animals.     

生茸期梅花鹿蛋氨酸螯合铜需要量的研究

为探讨生茸期梅花鹿日粮中铜的最适宜添加范围,将20只2岁雄性梅花鹿随机分成A、B、C、D共4组,每组5只。A组饲喂不添加铜的全价颗粒料,B、C、D组在全价颗粒料的基础上分别添加15、40、80 mg/kg蛋氨酸螯合铜。结果:梅花鹿生茸期日粮加铜,改善了营养物质消化率,除干物质外,对其他营养物质消化率影响均达到显著或极显著水平(P<0.05或P<0.01),变化趋势40 mg/kg时发生改变;梅花鹿生茸期日粮中添加铜对血液生化指标有影响,其中对血清铜蓝蛋白活性影响最为显著(P<0.05),当日粮铜添加量为40 mg/kg时,其活性达到最大值;梅花鹿日粮加铜,对血清及毛中铜含量影响显著(P<0.05);梅花鹿鹿茸产量随日粮加铜量的增加呈现先上升后下降的趋势,在日粮铜添加量为40 mg/kg时,茸产量达到最大值;梅花鹿鹿茸氨基酸含量随日粮加铜量的增加而增加,鹿茸含铜量随铜水平的增加呈现先上升后下降状态。综合各项指标,梅花鹿生茸期日粮铜的适宜添加量为40 mg/kg。     

Feed intake of young double-muscled bulls fed on grass and supplemented with sugar-beet pulp.

Daily dry matter intake in young growing double-muscled bulls, fed indoors on grass, was estimated based on forty-four intake data from 28 animals, ageing at least five months and weighing up to 400 kg live weight. Intake was measured during five consecutive days using one of eighteen cuts of grass. Fresh meadow grass (mainly Lolium perenne) was fed ad libitum and two kg dried sugar-beet pulp was offered per animal and per day. Animal live weight averaged 278 +/- 82 kg and mean total daily dry matter intake amounted to 5.05 +/- 1.59 kg or 73.6 +/- 13.7 g per kg metabolic weight, while pulp dry matter intake amounted to 1.49 +/- 0.50 kg per day. Regression analysis showed that animal as well as feed characteristics could explain up to approximately 90% of the variation in daily dry matter intake. The supplementation resulted in an extra daily dry matter intake of 0.68 g per g pulp dry matter. Intake of double-muscled animals was considerably lower than previously reported for non-double-muscled cattle. An extra supplementation of young grazing double-muscled animals could be advised from these findings, while extra protein should also be considered.     

Investigations on the water intake of growing bulls

The voluntary water intake was evaluated in 62 growing Holstein bulls (mean body weight range = 193 to 550 kg) during a whole fattening period. The diet was composed of corn silage and concentrates. Water was offered for ad libitum consumption. A total of 17,772 measurements of water intake were recorded over 282 days. The average daily water consumption was 18 kg/animal (S.D. = 6.7 kg). Applying a multiple regression analysis to the data set yielded the following equation: voluntary water intake (kg/day) = − 3.85 + 0.507  average ambient temperature (°C) + 1.494  dry matter intake (kg/day) − 0.141  roughage part of the diet (%) + 0.248  dry matter content of roughage (%) + 0.014  body weight (kg). The incorporation of the variables body weight gain, relative humidity, maximum ambient temperature, Na intake, and K intake into the equation did not increase the accuracy of the prediction.     

An estimate of the methionine requirement and its variability in growing pigs using the indicator amino acid oxidation technique

Although AA requirements for the mean of a population of growing pigs have been established using traditional methods, there are no estimates of the variability within the population and whether this variation differs among AA. With the increased use of supplemental Lys in pig diets, there will be an increased need to supplement Met, commonly the second or third limiting AA in corn-soybean diets. The indicator AA oxidation method allows repeated measurements in a short period of time so that the AA requirement can be determined for individual pigs at a similar physiological stage. The objective of this study was to determine the mean Met requirement in individual gilts and to estimate the related variability. Six individually housed female pigs (initial BW = 8.8 kg, SD 1.5) each received diets providing 6 levels of dl-Met. The isonitrogenous and isoenergetic diets contained 0.187, 0.250, 0.290, 0.320, 0.350, and 0.377% Met (analyzed, as-fed basis). Cysteine (0.48%) and Lys (1.44%) concentrations were similar for all diets. Pigs were adapted for 6 d to the basal corn-soybean meal diet (0.187% Met), which was offered at 95 g/kg(0.75) of BW to ensure complete consumption of the test diets. During 4-h oxidation studies, 313.4 kBq, (SD 35.6) of L-[1-(14)C]Phe was mixed with each of 8 half-hourly meals, and expired CO(2) was collected. The breakpoint in Phe oxidation, representing the Met requirement, and its variability, was determined using 2-phase linear regression. Phenylalanine oxidation decreased as the Met content increased from 0.187 to 0.29%. Phenylalanine oxidation was not different (P > 0.2) for diets ranging from 0.320 to 0.377% Met. The dietary Met requirement varied from 0.320 to 0.373% for individual pigs. The mean Met requirement for individual pigs was determined to be 0.340% of diet (SD = 0.024%, CV= 7.1%), with 0.340, 0.364, and 0.388% covering the requirement of 50, 66, and 95% of the population, respectively. The present mean population estimate was similar to the recommended dietary Met concentration of 0.325% for pigs of this BW and feed intake. To maximize profitability, Met levels in starter pig diets should be determined, depending on the cost of crystalline Met and the fraction of the population whose requirement is to be met.     

A case of hypertrophic osteoarthropathy in a Belgian blue cow

A 12-year-old cow was presented with chronic respiratory disease and lameness. Chronic pleuritis, pneumonia, and bronchial carcinoma were found as well as periosteal proliferation on limb bones. Ancillary tests and necropsy confirmed a combined pathology of pulmonary inflammation and neoplasm, and hypertrophic pulmonary osteopathy.     

Dietary methionine requirement of the Chinese egg-laying duck

1. The dietary methionine requirement of egg-laying ducks was assessed by feeding diets supplemented with graded levels of DL-methionine (0, 4, 8, 12, 16 g/kg dietary protein) for 8 weeks. The basal diet contained 175 g protein and 2.6 g methionine per kg feed (or 14.9 g/kg protein) and an estimated ME of 11.5 MJ/kg. 2. A total of 800 Shaoxin laying ducks (420 d old) were randomly divided into 5 groups of 160 each and fed in 4 separate pens. 3. Dietary supplementation of methionine significantly increased egg production and feed conversion efficiency. 4. Dietary methionine requirement for optimum egg production was estimated to be 25.7 g/kg of dietary protein or 4.5 g/kg of the diet or 380 mg/bird-d. 5. Methionine supplementation increased the methionine level in plasma, and the free glutamic acid and aspartic acid concentrations in plasma were quadratically related to dietary methionine levels. Increasing dietary methionine had little effect on egg quality characteristics.     

Factors affecting the incidence of pneumonia in growing bulls.

The occurrence of respiratory disease at two Meat and Livestock Commission bull performance test centres over a period of three years is assessed. During this period a change in the system of testing was introduced so as to allow younger bulls to enter the centre and also to increase their throughput. This resulted in an increase in the incidence of pneumonia of more than five times. The management at one centre was changed to counteract this disease problem and the level of pneumonia was greatly reduced. Most respiratory disease occurred within the first month of entry to the centres. There was more infection during the second half of the year and especially in the October to December quarter. There appeared to be some relationship between the time bulls were weaned prior to entry to the centres and the incidence of pneumonia.     

The determination of the methionine requirement of laying pullets by a diet dilution technique

A method for the determination of amino acid requirements of laying hens is described. This involves the dilution of a high protein “ summit” diet with an isocaloric nitrogen‐free mixture. By ensuring that the amino acid to be assayed is first‐limiting in the summit diet, the response to dilution can be interpreted as a response to a single amino acid.

The method is applied to the determination of methionine requirement and it is shown that the response to methionine obtained is virtually independent of the protein level of the diet and is not influenced by direct effects of the dilution mixture.

From the results of the present and other published experiments, the “ available “ methionine required for maximum egg yield of pullets in the early stages of lay is estimated to be 275 mg per bird per day.     

Response of growing goslings to dietary supplementation with methionine and betaine

1. An experiment with a 2 × 3 factorial design with two concentrations of dietary betaine (0 and 600 mg/kg) and three dietary concentrations of methionine (0, 600 and 1200 mg/kg) was conducted using goslings to estimate growth, nutrient utilisation and digestibility of amino acids from 21 to 70 d of age.

2. Three hundred geese were randomised at 18 d of age into 6 groups with 5 replicates per treatment and 10 geese per replicate.

3. Increasing dietary concentrations of methionine gave a linear increase in body weight and average daily gain. The coefficient of crude fat retention increased as dietary methionine increased and there was a significant non-linear response to increasing dietary methionine. Similarly, increasing supplemental methionine gave linear increases in the digestibility of methionine and cysteine.

4. The results of this study indicated that optimal dietary supplementation of methionine could increase growth performance and methionine and cysteine utilisation in growing goslings. Betaine supplementation had no apparent sparing effect on methionine needs for growth performance, but did improve the apparent cysteine digestibility.

     

The lysine requirement of the growing boar versus barrow

Five experiments were conducted to determine if boars and barrows differ in the level of dietary lysine required to maximize growth rate, efficiency of feed utilization, carcass leanness and N retention. In Exp. 1, 48 boars and 48 barrows were fed fortified corn-soybean meal diets calculated to contain 14 (grower) and 12% protein (finisher) and supplemented with 0, .15 or .30% lysine from 27 to 105 kg body weight. The basal diets analyzed .60 and .47% lysine, respectively. Linear improvements in feed/gain (P less than .01), backfat thickness (P less than .10), longissimus muscle area (P less than .01), and ham-loin (P less than .05) and lean cuts percentage (P less than .1) were observed in boars as dietary lysine increased. In barrows, however, growth rate, feed:gain ratio and carcass characteristics (except longissimus muscle area) were not significantly affected by dietary lysine level. In Exp. 2, 18 boars and 18 barrows initially averaging 64 kg body weight were fed a 12% protein diet (.47% lysine) supplemented with 0, .15 or .30% lysine. Linear (P less than .05) increases in N retention occurred in boars, but not barrows, as dietary lysine was increased. In Exp. 3 and 4, 140 boars (34 to 103 kg) were fed a 14-12% protein sequence (analyzed .61 and .48% lysine) supplemented with 0, .1, .2, .3 or .4% lysine. In Exp. 5, 60 boars (23 to 103 kg) were fed a 16-14% protein sequence (analyzed .83 and .68% lysine) supplemented with 0, .075, .15 or .225% lysine.(ABSTRACT TRUNCATED AT 250 WORDS)     

Comparison of external morphological traits of newborns to inner morphological traits of the dam in the double-muscled Belgian Blue Beef breed

In the double‐muscled (DM) Belgian Blue Beef (BBB) breed, caesarean section (CS) is used as a routine management tool to prevent dystocia. This practice is criticized on animal welfare grounds. With unassisted (natural) births, difficulties arise because of disproportion between the sizes of the newborn and inner pelvic sizes of the dam. In this study external morphological traits of newborns are compared with inner morphological traits of the dam. Results of this study indicate that in the DM‐BBB, CS is the only means to successful calving. Therefore, no calving ease scores are available to select for less dystocia in this breed. Selection for fewer CS must be achieved by focusing on lower birth weight (BW) and decreased muscular conformation at birth, both having a sufficiently high heritability. Simultaneously, pelvic sizes of the dam should be increased. It is very likely that the look of the DM‐BBB will change when selecting for less dystocia.     

Activity and requirement of selected amino acids in growing female pigs. 4. Combination of protein sources with lysine, methionine/cystine and threonine limitation

On the basis of the results of 3 previous articles on the efficiency of amino acids in single protein sources a total of 16 protein sources was tested maintaining the limitation relations of the combination partners with regard to the additivity of the efficiencies of lysine, methionine/cystine and threonine. The results of the N metabolism measurements with a total of 60 female pigs of the country breed type (30...55 kg live weight) allow the conclusion that additive relations and thus suitable correction possibilities exist for the gross amino acid content through the amino acid efficiency for the calculation of requirement and requirement meeting. The N utilization model used (GEBHARDT 1963) is in its further development confirmed as the basis of amino acid efficiency.     

Choline requirement of the laying hen. 2. Effect of methionine and fat content of rations on choline requirement

165 laying hens per group received 3.0, 3.5, or 4.0 g methionine, 29 or 59 g fat and supplements of 0, 108, 217, 434 or 868 mg choline per kg feed resp. (3 X 2 X 5) over a period of 336 days. The average laying performance was 70% and was not influenced values by the content of the feed. The methionine supplements significantly increased the weight of the eggs by 0.6 and 1.1 g resp. The higher fat content increased the weight of the eggs by 0.6 g. Feed expenditure was not influenced by the subject of the experiment. The results of the experiment show that laying hens do not require choline as feed supplement and that therefore no interactions between choline and the fat and methionine content of the ration are to be expected.