Digestible Organic Matter Content Research Articles

Pre‐harvest desiccation of crops for conservation

AbstractTwo experiments were conducted to determine the effect of pre‐harvest treatment by formic acid spray on the moisture concentration (MC) of perennial ryegrass (Lolium perenne) in vegetative growth. In Experiment 1 aqueous solutions containing 0.080, 0.148 and 0.259 kg formic acid per litre were applied to a perennial ryegrass sward (fresh matter yield 21.0 t ha−1) at a constant volume of 41.2 litres t−1to give active ingredient application rates of 3.5, 6.0 and 11.5 kg t−1 respectively. In Experiment 2 similar solutions were applied to a perennial ryegrass sward (fresh matter yield of 6.9 t ha−1) at 35.2, 19.0 and 10.9 litres t−1 respectively to give a constant formic acid application of 2.8 kg t−1. The changes in MC and chemical composition after treatment with acid were compared with those in untreated plotsIn both experiments treatment with acid significantly reduced the MC (P < 0.001) within 5 h of treatment from 4.4 to 3.0 kg per kg of dry matter (DM) in Experiment 1 and from 3.0 to 2.6 kg per kg DM in Experiment 2. There was no effect of level of acid applied in Experiment 1 or of the volume of water applied with the low level of acid in Experiment 2 on the changes in MC of acid‐treated plots. There was however a significant (P < 0.00l) difference between the MC of plots treated with acid and those untreated which was maintained in Experiment I for up to 9 d even during rainfall.There were no differences between the chemical compositions of samples from acid‐treated plots in either Experiment I or 2 or between untreated and acid‐treated plots in Experiment 2. However there were significant differences between untreated and acid‐treated plots in Experiment 1 for the content of nitrogen (N), water‐soluble carbohydrate (WSC) and digestible organic matter (DOM). There were changes in the content of N, WSC and DOM with time in both experiments. In Experiment I there was an interaction between sampling time and treatment for both N and WSC but not for DOM. Compared with untreated plots, treatment with acid at all levels accelerated the loss of WSC and delayed the fall in N content. There were no such interactions in Experiment 2.

The utilization of nitrogen and sulfur by weaner and mature merino sheep

The intake, excretion, and retention of nitrogen and sulfur were measured in weaner (liveweight 15-17 kg) and mature (40-45 kg) Merino sheep offered ad libitum amounts of three pasture hays. The hays (H, M and L) varied in their content of digestible organic matter (71, 59 and 45%), of nitrogen (2.84, 0.72 and 1.20%), and of sulfur (0.20, 0.13 and 0.09%). When given the most-digestible hay (H), the weaners retained more nitrogen than did the mature sheep (0.97 v. 0.81 g per l00g digestible organic matter intake (DOMI), but there was no difference in retention of sulfur (79 v. 74 mg per l00g DOMI)). However, on the basis of metabolic liveweight, the weaners incorporated more of both nutrients into tissues, while the mature wethers incorporated more nitrogen and sulfur into wool. The retention of nitrogen and of sulfur per unit of DOMI were similar for each age group of sheep when the medium quality hay (M) was given. Mature sheep again incorporated more of each nutrient into wool. With the poorest quality hay (L), the weaners excreted more nitrogen and sulfur as a proportion of the amounts consumed than did the mature sheep. This resulted in a lower retention of nitrogen (-1.45 v. -0.74 g per l00g DOMI) and sulfur (-77 v. -14 mg per l00g DOMI) by the weaners. There was a lower incorporation of nitrogen into tissues per unit of metabolic liveweight by the weaners, and the mature sheep incorporated more nitrogen and sulfur into wool. The weaners grew wool less efficiently (g per l00g DOMI) than the adult sheep on all diets, the difference being greatest when the poorest quality hay was given. These results are discussed in relation to the nature of tissue energy reserves in weaner sheep.

Genotype-environment interactions in fodder kale (Brassica oleracea L.)

SUMMARYTwo potential new kale cultivars were compared with five control cultivars in 12 trials involving five sites in the north of England and the south of Scotland, 2 years, and a range of sowing and harvest dates.The differences between cultivars were small for dry-matter and digestible organic-matter yield. Genotype-environment interactions were relatively large by comparison and hence only tentative estimates could be made of relative yield performance in a wider range of environments. However, the set of trials was satisfactory for determining the heights, dry-matter contents and digestible organic-matter contents of the cultivars despite the presence of statistically significant genotype-environment interactions.Joint regression analyses revealed that the two cultivars with the lowest mean freshweight yields were also the least responsive to environmental change and that environments resulting in low digestible organic-matter contents were best for discriminating between cultivars.

The effect of cultivar and harvest date on the chemical composition and digestibility of fodder kale

AbstractThe chemical composition and digestibility of seven marrow‐stem, three thousand‐head, and two curly kales were determined during the period from September to March. Differences between cultivars and between harvest dates were found for all of the characteristics assessed, but cultivar by harvest date interactions were not a serious problem. The largest differences in dry matter (DM) content were between the two curly kales (17.7%) and the other ten cultivars (14.0%), and between the mid‐September harvest (11.3%) and the three later harvests (15.8%). Then, expressed as a percentage of the DM, the main results were as follows. The organic matter (OM) content was low in the mid‐September (85.9 compared to 90.1) and contributed to a low digestible OM content (68.5 compared to 72.2). Amongst the marrow‐stem kales were the extremes for digestible OM, namely 68.6 in an un‐named marrow‐stem stock and 73.5 in Maris Kestrel. The crude protein content fell from 22.1 in mid‐September to 15.7 in mid‐November, and then rose to 17.4 in January and March. The S‐methyl cysteine sulphoxide (the haemolytic factor) content increased from 0.692 in mid‐September to 1.21 in January and March, when the curly kales had 41% higher contents than the marrow‐stem kales. The extreme thiocyanate ion (a goitrogen) contents occurred in mid‐November (0.0152) and mid‐January (0.0336), and ranged from 0.0157 in the marrow‐stem cultivar Merlin to 0.0334 in the dwarf thousand‐head cultivar Canson. Although not a yield trial, it was found that on average the DM yield of the curly kales was only 55% that of the marrow‐stem and thousand‐head kales.

Predicting the energetic value of forage from digestibility of organic matter in vitro or solubility in potassium hydroxide

The digestibility of dry matter, organic matter and energy, and the content of digested energy, were determined on 56 diets, including hay, haylage, silage and pellets, in balance trials with wethers. All diets were analysed for solubility of organic matter in KOH, total protein, crude fibre, N-free extract and digestible organic matter content determined in vitro (D value). The D value proved to be the most accurate in vitro method for predicting digestible energy value in vivo. Solubility of organic matter in KOH and crude-fibre content predicted the energy value of the diet with less accuracy. Regression equations are presented for predicting the organic matter digestibility and energy value of the diets from the results of laboratory analyses.

Milk production from silage 2. The influence of the digestibility of silage made from the primary growth of perennial ryegrass

ABSTRACT1. The primary growth of perennial ryegrass (Lolium perenne cultivar Endura) was cut on 23 May (high digestibility) and 23 June (low digestibility) and ensiled with an additive consisting of equal volumes of formic acid and formalin to supply 30 g formaldehyde per kg crude protein. The silages were given ad libitum, together with 6·3 kg dry matter per day of a barley/soya bean supplement, to 24 British Friesian cows over weeks 4 to 18 of lactation.2. The delay in cutting the primary growth led to an increase in grass yield from 3·78 to 6·94t dry matter per ha but a depression in the content of digestible organic matter in the silage dry matter from 748 to 639 g/kg. However, the effect of the digestibility of the silage on the digestibility of the total diet by the cows was small. The silages contained low levels of fermentation acids and ammonia-nitrogen.3. The digestibility of silage did not influence silage dry-matter intake in early lactation but in mid lactation the intake of the low-digestibility silage declined whilst that of the high-digestibility silage increased slightly.4. Cows given silage of high rather than low digestibility produced significantly more milk (high, 28·0 v. low, 24·7kg/day, P < 0·01 ) of lower fat content (high, 36·1 v. low, 41·0 g/kg, P < 0·01 ) but higher protein content (high, 31·5 v. low, 29·4g/kg, P < 0·05). Cows given silage of low digestibility lost more live weight than cows given silage of high digestibility but the effect was not significant.

Liveweights and ration digestibilities for steers fed oat or wheat rations at near maintenance level

Steers of 252 kg initial mean liveweight were fed 0.44 kg of hay dry matter (DM)/head day-1 plus five rates of whole oats, crushed wheat or whole wheat, with the crushed wheat rations providing 0.7 to 1.3 times the estimated energy for maintenance. All-grain rations at these energy levels had been attempted, but resulted in digestive upset, and were abandoned. The results obtained, listed in the order of the above grains, were : 1 ) grain in ration to maintain liveweight: 1.31, 1.41 and 1.85 kg DMIhead day-1 ; 2) additional grain for each 10 kg improvement in liveweight over I2 weeks: 434,466 and 61 3 g DMIhead day-1 ; 3) mean digestible organic matter content (DOM) of rations, tested at the highest and lowest rates of grain : 69.4, 84.5 and 68.3%. The DOM of the oat rations declined by 8.1 units from the lowest to highest rate of grain. The relative liveweight change on oats could not be explained by the DOMs. Nevertheless, the results suggest, for similar conditions to those applying in our experiment, that: 1) whole oats may be at least as good a feed as crushed wheat, and both will be much better than whole wheat; 2) the feed requirement for maintenance may be about 20% less than standard recommendations; 3) even a little hay in the ration, compared with grain only, may greatly reduce the likelihood of digestive upset

Maize silage for milk production: The influence of concentrate supplementation and the effect of adding urea or ammonia before feeding

ABSTRACT1. Thirty lactating British Friesian heifers and cows were individually given maize silage ad libitum containing 331 g dry matter/kg, 13 g nitrogen and 11·2 MJ of metabolizable energy per kg dry matter. Urea or aqueous ammonia was mixed in at the time of feeding to give 7·0 g nitrogen per kg silage dry matter. Urea-treated silage was given with concentrates at a high (mean 6·6 kg dry matter/day: treatment HU) or a low (mean 3·3 kg:treatment LU) level of feeding; the lower level only was given with ammonia-treated silage (treatment LA).2. The addition of ammonia raised silage pH values from 3·9 to 4·4. Silage dry-matter intakes in lactation weeks 7 to 22 for treatments HU, LU and LA were 8·8, 11·1 and 10·7 kg/day.3. Digestible organic matter content in the dry matter of the diets measured in vivo was not significantly affected by treatment. However, digestible organic matter intakes were significantly greater for treatment HU than for LU in weeks 7 to 10, and for LU than for LA in weeks 11 to 22.4. The yields of milk and the contents of protein, lactose and energy did not differ between treatments. The milk yields for treatments HU, LU and LA in weeks 7 to 22 were 20·2,19·2, 18·8 kg/day respectively. Fat content of milk was significantly depressed with the HU treatment for heifers in weeks 7 to 10. The live-weight changes of the cows in weeks 7 to 22 for treatments HU, LU and LA were +0·10, −0·07 and −0·37 kg/day; the live-weight loss by cows given treatment LA was significantly greater than for LU. The live-weight change of the heifers was not affected by treatment.

A new system for the protein feeding of ruminants: The PDI system

To replace the digestible crude protein system (DCP) a new system is proposed which is named the PDI system (Protéines Digestibles dans l'Intestin grêle). It estimates the quantity of amino nitrogen N × 6.25 absorbed in the small intestine from the dietary protein which has escaped fermentation in the rumen, and the microbial protein arising from that fermentation. The extent of N degradation in the rumen and the microbial protein yield (135 g/kg of digestible organic matter intake) were obtained using an equation describing the flow of non-ammonia N entering the duodenum. The true digestibility of microbial true protein (80% of microbial crude protein) was considered equal to 0.70 and that of dietary protein was calculated from nitrogen and organic matter digestibilities of each feed. Two PDI values are ascribed to each feed: one (PDIN) calculated from both its non-degradable N and degradable N contents and the other (PDIE) from both its non-degradable N contents and its content of rumen available energy (in fact its digestible organic matter content). When calculating the PDI value of a diet, the PDIN and PDIE values of the different ingredients are summed separately: the PDI value of the diet is the lower of the two values. The PDI requirements of animals have not been measured previously. They were calculated from nitrogen balance trials on non-producing animals and from feeding trials on producing animals. The mean efficiency of PDI utilization was found to be 0.67 for milk production in cows, 0.60 for body gain in cattle and 0.60 for pregnancy in sheep. These values have also been used with animals of other species. The advantages of the PDI system over the DCP system, as well as its shortcomings, are discussed. It is compared with alternative systems which have been proposed recently in other countries.

The development of plant components and their effects on the composition of fresh and ensiled forage maize: 2. The effect of genotype, plant density and date of harvest on the composition of maize silage

SummaryForage maize was harvested on three occasions from three genotypes (Inra 200, LG11 and Anjou 210), grown at three plant densities (5·0, 9·8 and 13·5 plants/m2). Three replicate silos were filled with 8 kg fresh crop per treatment, sealed, and stored for 100 days.Crops from all treatments fermented to give predominantly lactic acid, low values for pH (average 3·9, range 3·7–4·1), with no butyric acid. Apparent loss of watersoluble carbohydrates during storage appeared to be directly related to their content at harvest.Genotype and plant density had relatively little effect on the composition of the silage, or on digestibility in vitro. Later harvest was reflected in increased contents of dry matter and starch, and in restricted fermentation. The content of digestible organic matter in the D.M. was decreased by later harvest.

PREDICTION OF DIGESTIBLE ENERGY INTAKE BY SHEEP OF DIETS CONTAINING GROUND ROUGHAGE AND GRAIN

Digestibility and intake of diets containing 8, 28, 48 or 68% ground wheat straw plus ground crested wheatgrass and rapeseed meal, and diets containing 33, 48, 63 and 78% ground crested wheatgrass plus barley and rapeseed meal was measured with four yearling wethers per diet. Digestible energy (DE) content ranged from 2.07 to 2.95 kcal/g dry matter (DM) and dry matter digestibility (DMD) (%) from 48.7 to 71.1%. Regression of DE intake y (kcal/w0.75kg/d) on DE content (x) was curvilinear; y = −2,133 + 1,626x − 277.9x2, r = 0.996, P < 0.01, SE = ± 7.3. There was also a curvilinear relationship between diet density, as fed, (x) g (DM)/ml and DMD (%), y = 9.057 + 364.1x − 530.0x2, r = 0.970, P < 0.01, SE = ± 2.4. A linear regression equation was calculated over the DE range (2.07–2.52) for which there was an obvious increase in DE intake with increasing diet DE content; y = −700.6 + 361x, r = 0.994, P < 0.01, SE = ± 9.4, y = DE intake (kcal/w0.75kg/d), x = DE [kcal/g (DM)]. Using this regression equation and assuming a linear increase in DE intake with increase in diet DE content up to a point at which the apparent energy demand of the animal is satisfied gave a more accurate prediction of DE intake than when the curvilinear regression equation, y = −2,133 + 1,626x − 277.9x2, was used empirically. Accuracy of the prediction was further improved by expressing DE/unit ration volume instead of per unit DM. The sheep used in the present experiments had an apparent energy demand of 230 kcal/w0.75kg/day which was met at diet DE contents above 0.48 kcal/ml or 2.6 kcal/g (DM). There was a high correlation between in vivo DE content of the diet, y [kcal/g (DM)] and in vitro (x) digestible organic matter content, x, (%), r = 0.991, P < 0.01, y = 0.38 + 0.037x, SE = ± 0.04.

Determination of nitrogen requirement for microbial growth from the effect of urea supplementation of a low N diet on abomasal N flow and N recycling in wethers and lambs.

1. Plasma urea entry rate, urinary area excretion and, by difference, urea recycling in the body, together with the flow of non-ammonia N through the abomasum and digestion of dry matter (DM) before the abomasum were determined in both wethers and lambs receiving cereal-starch diets supplemented with urea to give 60-120 g crude protein (N X 6-25)/kg DM. 2. Lambs excreted less urea in urine than wethers given the same diet. 3. Relationships between plasma urea entry rate or urine urea excretion rate and plasma urea concentration were different for lambs compared to wethers suggesting greater conservation of body N by renal control in lambs. 4. Recycling of urea was not related to plasma urea concentration in wethers but was related exponentially in lambs, suggesting recycling is controlled rather than the result of simple diffusion from the blood to the gastro-intestinal tract. 5. Abomasal non-ammonia-N flow was similar for wethers and lambs and increased linearly with urea supplementation. 6. DM digestion prior to the abomasum was not significantly altered, although there was a tendency for decreased digestion of the basal diet given to lambs. 7. Maximum microbial N flow to the abomasum was estimated as 30 g N/kg organic matter (OM) fermented in the rumen. 8. This work and the literature reviewed suggested maximum net microbial production can be obtained when the diet supplies an amount of fermentable N equal to the microbial N output. It is calculated the diet should supply approximately 26 g fermentable N/kg digestible OM or 1-8 g fermentable N/MJ metabolizable energy. This corresponds to a fermentable crude protein supply varying from 65 to 130 g/kg DM as digestible OM content increases from 400 to 800 g/kg DM.

Value of lucerne cobs for milk production

SUMMARYThree changeover experiments, each with 16 milking cows, were conducted to evaluate the effects of stage of growth of lucerne, level of feeding of lucerne or ryegrass and level of inclusion of barley. The artificially dried and processed forages were in the form of cobs and given to cows in addition to a basal ration of hay. Late-cut lucerne (organic matter digestibility, OMD, 55%) promoted significantly lower milk yields than early-cut lucerne (68% OMD). When offered ad libitum in two meals each day both forages were eaten in quantities of about 13 kg dry matter. Ryegrass cobs (79% OMD) produced more milk than lucerne cobs (59% OMD) but gave similar milk yields per unit of digestible organic matter. Production rations supplying similar amounts of digestible organic matter and composed of different proportions of lucerne cobs and rolled barley gave similar milk yields. It is concluded that the relative milk-producing value of processed forages depends on their content of digestible organic matter. However, their bulk may limit their value and the inclusion of cereal with the dried forage may be worth while.

Determination of feeding value based on simple food characteristics. 1. Determination of the digestibility of green foods and their preservation products

Regression techniques may be used to establish close relations between the crude fibre content and digestibility data of organic materials (total digestibility). It was shown from regression equations calculated for a number of feedingstuffs that the total digestibility of a feedstuff may be calculated, with a sufficient degree of accuracy, from the crude fibre content of the material. The range of variations from most of the digestibility data obtained for various feedstuffs, was clearly below the limit given (2.5%). When regression equations are used the variation limits should always be indicated for which they had been established. Differences within the different groups of feedstuffs are so small that in many instances, the same equation may generally be used for feedstuffs of the same group. Similarly, equations for calculating digestibility values may be derived on the basis of the lignin content of a material, although the range of variations will, in this case, be wider when compared with the crude fibre content. The reason for this must be seen in the greater uncertainty of the lignin method. Analogous regression equations may be found for the different conserving products of green feeds, in which certain alterations have to be made corresponding to the different methods of conserving used. On the one hand, these are accounted for by changes in the crude fibre content brought about by biochemical reactions during the conserving process on the other hand a special influence of conserving form can be observed. The content of digestible crude protein in green feeds can be established, with a high degree of accuracy, from the crude protein content of the material. The content of digestible organic matter can be calculated from the digestibility of organic matter and from the ash content of the material. The content of digestible organic matter is, in turn, closely related to the content of energetic feed units in a particular material.

Forage and sheep production from oats, rape and vetch sown in autumn with or without nitrogen fertilizer

Oats (Avena sativa cv. Acacia), vetch (Vicia dasycarpa cv, Lana) and rape (Brassica napus cv. Rangi) were sown with or without 67 kg ha-1 nitrogen (N) in the autumns of 1969 and 1970 at Armidale, N.S.W. In both years the crops were rotationally grazed by sheep in late winter and spring at two fixed stocking rates (experiment 1). When grazing began in both years oat dry matter (DM) availability was approximately double that of vetch and rape. Oats remained highly productive in successive grazing periods whereas the recovery of vetch after the first grazing was slow. At the high stocking rates employed the rape crops were overgrazed and failed to regrow. Fertilizer N increased oat yields by more than 50 per cent and N content by 20 to 40 per cent, but neither vetch nor rape responded significantly. Minimum nitrogen contents of oats, rape and vetch were respectively 1.3, 2.7 and 4.0 per cent. Digestible organic matter content of the three forages exceeded 74 per cent throughout the experiment. Daily rates of liveweight gain per sheep were not significantly different on the three crops in the first grazing period. Daily gain per sheep responded significantly to fertilizer N only on oats in the second period in 1970 (P < 0.05). The total liveweight gain ha-1 pooled over all periods was much greater on oats than on vetch or rape. Clean wool per day tended to be higher on vetch than on the other crops but total wool production per hectare was greatest from oats in both years because of the longer period of grazing it provided. In a supplementary experiment (experiment 2) in 1969 the crops were grazed at an initially uniform stocking pressure (1 sheep per 10 kg dry matter available). Sheep grazing vetch gained 146 g head-1 day-1 which was faster than sheep on oats (92 g head-1 day-1) or rape (66 g head-1 day-1) (P < 0.05). The general effect of N fertilizer was to increase daily gain and almost double the mean gain per hectare.

A comparison between a dploid and a tetraploid ryegrass for milk production

SummaryTwo perennial ryegrass swards – one consisting of S. 24, a diploid variety, and the other of Reveille, a tetraploid variety – were compared in a 20-week grazing experiment with 16 Ayrshire cows in 1968 and again with 12 cows in 1969. Each grass sward was grazed at either a high or a low rate of stoeldng and no other feeds were offered to the cows. On average, the amount of herbage dry matter on offer to the cows was slightly greater on the S. 24 than on the Reveille sward but the contents of total soluble sugars and digestible organic matter were significantly higher in the dry matter of the Reveille than in that of the S. 24. The crude protein contents of the herbage dry matter were similar on the two swards. The mean daily milk yields from cows grazing at the high and the low rates of stocking in 1968 were 14·0 and 15·7 kg/cow respectively on the S. 24 sward and 14·7 and 16·1 kg on the Reveille sward. In 1969 the milk yields from these same treatments were 15·4 and 17·2 kg on the S. 24, and 16·5 and 17·7 kg on the Reveille. The fat content of the milk was not significantly affected by the treatments. In both years the solids-not-fat and the crude protein contents of the milk were higher on the Reveille than on the S. 24 sward, but these differences were significant at the low rate of stocking only. The live weight of the cows did not differ significantly between the two swards. The average output of milk per hectare was approximately 4% higher from the Reveille than from the S. 24 sward but the major factor influencing milk production per hectare was the stocking-rate. On average over the 2 years the output of milk per hectare was 36% higher on the high than on the low rate of stocking. It is suggested that in selecting herbage for milk-production purposes attention should be paid to material with a high digestible organic-matter content and a high content of soluble sugars.

FEEDING VALUE OF FORAGE AS FED TO STEERS AND ESTIMATED BY IN VITRO DIGESTION

The digestibility and intake of 23 hays and three silages were determined in two experiments with Hereford steers averaging 215 kg at the start of the test. Each forage was fed in a chopped (4 to 6 cm) form as the sole diet to two steers for 56 days. Voluntary intake and body weight gain during the fourth through the seventh week were used as measures of animal performance. Digestibility was determined by collecting all the feces during the eighth week, allowing for a three-day lag between intake and excretion. The forages included grass, legume and cereal hays, and cereal and legume cereal silages produced under a wide range of conditions. The concentration of in vitro digestible organic matter (DOM) in the forage was highly correlated with gain (r = 0.57 and 0.86) and intake of digestible energy (DE) (r = 0.62 and 0.89). The voluntary intake by the steers was comparable with that by sheep in earlier experiments at two other locations, when the intake was based on metabolic body size, and on similar in vitro DOM or in vivo DE concentrations in the forage. Differences in intake between experiments followed the same pattern as feed allowance in excess of intake, but the effect of in vitro DOM or in vivo DE content on intake was apparently the same in each experiment. This supported the theory that regressions of DE intake by sheep on in vitro DOM content of forage will serve as a measure of the feeding value, providing that appropriate experimental conditions are maintained.

Nutrient digestibility and growth of local bull calves as affected by feeding urea and urease enzyme sources treated rice straw

The experiment was conducted for a period of 75 days to study the effect of treatment of straw with urea or with urea and a urease containing chick pea seed meal and midden soil on chemical composition of treated rice straw, feed intake of the animals, nutrients digestibility, body weight gain, and feed conversion efficiency. For the study twelve indigenous growing bulls aged approximately 20 months and weighing 115.16 ± 1.50 kg were divided into four groups having three animals in each group. The animals of group A received 3.5% urea treated fresh straw, group B received 3.5% urea treated ensiled straw, group C received 3.5% urea + 2.5% midden soil treated ensiled straw and group D received 3.5% urea + 2.5% chick pea treated ensiled straw. All the animals were supplied with treated rice straw, green grass and concentrate mixture. Rice straw treated with 3.5% urea resulted an improvement in crude protein content of rice straw from 3.33 to 7.70 and 8.10 % (without ensiling and ensiling) which was further increased by 8.20 and 9.50% with the addition of 2.5% midden soil and 2.5% chick pea seed meal at the time of treatment. Significantly higher (P<0.05) daily dry matter intake was observed in animals fed diet D (4.42) followed by diet C (4.39), diet B (4.34) and diet A (4.12). The total CP intake by the animals of D groups was significantly higher (P<0.01) than that of the animals receiving diet A, B and C. During the 75 days trail, the total live weight gains were 30.50, 35.17, 38.17 and 39.83 kg for bull calves fed diet A (3.5% urea treated straw without ensiling), diet B (3.5% urea treated straw with ensiling), diet C (3.5% urea + 2.5% midden soil treated straw) and diet D (3.5% urea + 2.5% chick pea seed meal treated straw) respectively. The daily live weight gains were 0.41, .047, 0.51 and 0.53 kg in groups A, B, C and D respectively. Midden soil and chick pea seed meal addition with treated rice straw not only significantly (P<0.01) increased the coefficient of digestibility of DM, CP, and CF but also significantly (P<0.05) increased the coefficient of digestibility of OM, NFE than only urea treated straw (both without ensiling and ensiling). Addition of urease sources also increased (P<0.01) the digestible crude protein (DCP), digestible ether extract (DEE). Digestible nitrogen free extract (DNFE), digestible organic matter (DOM) and total digestible nutrients (TDN) contents were significantly (P<0.05) higher in diet D in comparison to diet A, B and C. Key words: Bull calves; Digestibility; Midden soil; Urea; Urease DOI: http://dx.doi.org/10.3329/bjas.v39i1-2.9682 Bang. J. Anim. Sci. 2010, 39(1&2): 97-105

The value of a poultry litter and wheat mixture in the drought feeding of weaner sheep

At the end of 23 weeks the mean daily dry matter intake of Merino weaners was 190 g of poultry litter and 235 g of wheat. The mean weekly body weight gain, 210 g per sheep, was not significantly different to weaners that consumed a mean daily dry matter intake of 365 g of wheat grain and gained 180 g weekly. The mean digestible organic matter content of wheat and poultry litter were calculated to be 88 and 31 per cent respectively. Weaners fed wheat only were not supplemented with limestone (1.5 per cent) for 13 weeks by which time two of the eight weaners had serum calcium levels below 8 mg per 100 ml. One of these weaners had gained weight, the other had lost weight and died three weeks after limestone supplementation. The addition of limestone did not increase the mean serum calcium levels significantly, but at the end of the trial all weaners had levels above 8 mg per 100 ml. ' Serum glutamate oxalacetate transaminase and bilirubin concentrations were higher for weaners fed wheat-litter mixture, but below levels normally associated with liver dysfunction. Reasons for caution in the use of poultry litter in the manufacture of commercial feedstuffs for ruminants are discussed.