Chopped Straw Research Articles

Intake and digestibility of untreated and urea treated rice straw base diet fed to sheep

Rice straw as one of agricultural by-products has low quality due to low content of essensial nutrients like protein, energy, minerals and vitamin as well as poor palatability and digestibility. Therefore, the quality of rice straw needs to be improved in order to increase its utilization by gastrointestinal tract of ruminants. The purpose of this study is to compare untreated and urea treated rice straw as basal diets for sheep. Twelve mature Merino wethers (average body weight 53.62 + 3.44 kg) were separated into 4 groups based on their live weight with each groups assigned three diets, that are: diet 1 untreated rice straw with high forage legume content, diet 2 urea ensiled rice straw and diet 3 rice straw sprayed with urea solution at feeding time. Diets were allocated based on a randomized complete block design. Urea ensiled rice straw was prepared by spraying chopped straw with urea solution to yield straw containing 4% urea and 40% moisture, then kept in air tight polythylene bags for 6 weeks. The untreated, ensiled and urea supplemented rice straw were mixed with other feed ingredients to provide isoenergetic and isonitrogenous diets. Diets were formulated to meet maintenance requirement according to NRC. Sheep were adapted to experimental diets for 15 days, and after adaptation period, a metabolism trial was conducted. Results reveal that dry matter intake permetabolic body weight (DMI/W0.75), DE (digestible energi) intake and apparent digestibility of NDF (neutral detergent fibre) were not significantly different between diet 1 and diet 2. Apparent digestibility of DM (dry matter), OM (organic matter), and ADF (acid detergent fibre), as well as N retention were not significantly different between three diets. Positive result in N retention was only observed in diet 2, while others were negative. It may be concluded from this study that untreated rice straw basal diet supplemented with forage legume offer an alternative method other than urea ensiled for improving the nutritional value of rice straw as a ruminant feed on small farmer. Key words : Rice straw, urea treated, digestibility, and sheep

SE—Structure and Environment: Carbon Dioxide Emission and Water Evaporation from Deep Litter Systems

Carbon dioxide emission and water evaporation from deep litter systems are important parameters to consider when designing ventilation and heating in livestock buildings. The objective of these investigations was to determine the CO2emission and water evaporation from deep litter with different bedding materials and also the water evaporation from a manure alley (solid floor). Five different studies are presented, two with deep litter for young cattle and three with deep litter for growing/finishing pigs. The bedding materials used were; long straw, chopped straw, chopped straw with reduced (25%) bedding amount, chopped straw with additives (four different), wood shavings and a mixture with 60% peat and 40% chopped straw. The investigations with deep litter for young cattle were conducted during two 6-month periods and the investigations with deep litter for growing/finishing pigs were conducted during three growing periods. Animal density in the pens varied between 27–101 and 22–90 kg m−2for cattle and pigs, respectively. Ventilated chambers (bottom area 0·25 m2) placed on the top of the litter were used in four studies. In a fifth study, with deep litter for growing/finishing pigs, the measurements were at building scale in the ventilated air when pigs were moved outside the research building.The average CO2emission rate measured by ventilated chambers varied between 24·0–87·9 and 23·0–82.2 g m−2h−1for cattle and pigs, respectively. The average water evaporation varied between 109·2–159·8 (cattle) and 70·3–190·6 g m−2h−1(pigs). From the manure alley (solid floor), the average water evaporation rates in two studies (cattle) were 73·2 and 110·5 g m−2h−1. The water evaporation rate varied during the measuring periods, with the minimum occurring during winter months. For young cattle, long straw as bedding material had a significantly higher CO2emission rate compared with chopped straw. The mixture of peat and chopped straw had a significantly lower CO2emission rate and water evaporation rate than long straw and chopped straw. For growing/finishing pigs, wood shavings as the bedding material had a significantly lower CO2emission rate and water evaporation rate compared with long or chopped straw. The four different additives used had no significant effect on the CO2emission rate or the water evaporation rate. The CO2emission rate measured at building scale was lower than from the measurements with ventilated chambers, between 12·9 and 21·9 g m−2h−1, and the water evaporation rate was between 135·6 and 210·5 g m−2h−1.

Effects of Protein and Carbohydrate Supplements on Feed Digestion in Indigenous Malaysian Goats and Sheep

Experiments were conducted to determine the effects of soybean meal (SBM) as a source of protein and sago meal (SM) as a source of carbohydrate on in situ and in vivo digestibility of dietary components in four male goats (Kambing Katjang) and four male sheep (Malin) weighing 25-35 kg. Rumen volume, as well as rumen fluid dilution rate were also determined. The animals were housed in single pens with individual feeding and drinking troughs and each animal was fitted with a rumen fistula. They were fed two diets : chopped rice straw+200 g soybean meal (SBM), and chopped rice straw+190 g soybean rneal+300 g sago meal (SBM+SM). Rice straw was offered ad libitum. The supplements were isonitrogenous (80 g crude protein/animal/d), but the proportions of dry matter (DM), organic matter (OM), crude fibre (CF), neutral detergent fibre (NDF) and acid detergent fibre (ADF) were lower in the SBM supplement (191, 165, 11, 40, 15 g/animal/d for DM, OM, CF, NDF and ADF, respectively) than in the SBM+SM supplement (445, 423, 25, 102, 38 g/animal/d for DM, OM, CF, NDF and ADF, respectively). Two animals from each species were fed either supplement in a cross-over design in two periods. Each period lasted for four weeks. In situ and in vivo digestibility studies were carried out, followed by the determination of rumen volume and rumen fluid dilution rate. The results showed that straw DM and total DM intakes of goats (average of 48.7 g/kg W0.75, 72.7 g/kg W0.75, respectively) were significantly (p<0.01) higher than sheep (average of 35.6 g/kg W0.75, 61.6 g/kg W0.75, respectively), but OM, N and GE intakes were not significantly different between the two animal species. When the effect of supplements was compared, animals fed SBM+SM supplement had significantly (p<0.001) higher DM, OM and GE intakes than animals fed SBM supplement. Potential degradabilities of rice straw DM were significantly (p<0.01) higher in goats (average of 48.8%) than in sheep (average of 46.1%). The supplements had no significant effect on the potential degradabilities of DM, OM and NDF, but they had a significant (p<0.05) effect on the degradation rates of DM and NDF. The addition of sago meal in the diet reduced the degradation rates of DM and NDF of rice straw in the rumen. Potential degradability of DM of soybean meal was not significantly different between animal species as well as between supplements. Sago meal was highly degradable. At 24 h of incubation in the rumen, 90-95% of DM loss was observed. There was a significant interaction between animal species and supplements in the m vivo digestibility of ADF and GE. In animals fed SBM supplement, the in vivo digestibility of ADF was significantly (p<0.05) higher in goats (50.6 ± 4.22%) than in sheep (44.4 ± 3.21%), but digestibility of GE was significantly (p<0.05) higher in sheep (70.2 ± 1.93%) than in goats (63.0 ± 3.07%). The digestibility values of CP and OM were significantly (p<0.05) higher in sheep when compared to goats. Animals fed SBM+SM supplement showed significantly (p<0.05) higher DM and OM digestibility values than animals fed SBM supplement, but digestibility values of CP were significantly (p<0.05) higher in animals fed SBM supplement. Differences in in vivo digestibility values of CF and NDF were not significantly different between animal species or supplements. Water intake, rumen volume (1/kg W0.75), rumen fluid dilution rate and mean retention time were similar between the two animal species. However, rumen fluid dilution rate and mean retention time was significantly (p<0.01) affected by supplements. Animals fed SBM+SM had faster rumen fluid dilution rate and consequently shorter mean retention time.

Interactions of Straw Disposal Methods and Direct Drilling or Cultivations on Winter Wheat (Triticum aestivum) grown on a Clay Soil

A field experiment was started in 1979 on a clay soil to compare effects of baling to leave stubble only, chopping and spreading straw or burning on the yield of winter wheat (Triticum aestivum). Results are reported for the period 1982–1988 with occasional references to earlier years. The crop was either direct drilled or sown after incorporation of straw or ash by cultivation to depths of 5, 15 or 25 cm. Tine cultivation was used until 1983 then replaced by ploughing. Averaged over a nine-year period, direct drilling into chopped straw caused a one-third reduction in yield compared to direct drilling where the straw was burnt. Over the same period, 5 cm deep straw incorporation resulted in one-fifth less yield compared to crops after burning. From 1985 to 1988, ploughing to 15 or 25 cm resulted in respectively 1 and 9% less yield if straw was incorporated rather than burnt. There was no evidence that these reductions were a consequence of consistent differences in pests or diseases.Temporary (1 year) burning after seven years of incorporating chopped straw increased average yield on tillage treatments by 17%. On this soil, ploughing at least to 15 cm is recommended to improve reliability of crop establishment. The average yields obtained from the straw returned treatments indicates that it was the presence of straw rather than the amount that most influenced yield.

Volatilization of Ammonia in Deep-litter Systems with Different Bedding Materials for Young Cattle

Ammonia volatilization from animal husbandry contribute to the total nitrogen deposition, causing acidification and eutrophication. The objective of this investigation was to compare ammonia volatilization from deep-litter housing systems using different bedding material and to compare the ammonia volatilization from the beds with that from the manure alley. Four different bedding materials were compared; long straw, chopped straw (with and without an additive) and a mixture with 60% peat and 40% chopped straw. The effect of an additive containing sea algae and vegetable oils on ammonia emission was evaluated. The experiments were conducted during a six-month period in four bedded pens with a manure alley for young cattle. The ammonia emission rate from the beds and the manure alley, the temperature in the beds, the chemical composition of the bedding materials, the thickness of the beds and the cleanliness of the cattle were determined in the investigation. Six ventilated chambers were used to measure the ammonia emission rate.The ammonia emission rate from the bed with a bedding mixture of 60% peat and 40% chopped straw (dry matter weight) was significantly less than from the beds with long straw or chopped straw. The mixture of peat and chopped straw was estimated to reduce the ammonia emission by 57% compared with long straw. The ammonia emission rate from the manure alley (solid floor) was significantly less than from the bedding area with long straw or chopped straw as bedding material. From the manure alley, the ammonia emission was estimated to be 40% of the emission from the bedding area with long straw. The additive evaluated did not have any effect on the ammonia rate. It was also found that the temperature was an important factor for ammonia emission rate.

Performance and Carcass Characteristics of Feedlot Cattle Fed Ensiled Soybean Straw Treated with Various Alkalis

ABSTRACT A beef growing-finishing study was conducted to determine the effects of feeding ensiled chopped soybean straw (SBS) (35% dry matter) treated with various alkalis on performance carcass characteristics. Concentrations of alkalis used in the diets were either 0 (control) or 4% (w/w) of the straw dry matter. A fescue hay (FH) diet was used as a positive control. Thirty-five Angus and Hereford steer and heifer calves averaging 202 kg body weight were randomly assigned to 5 treatment groups. Treatments were: (1) water, (2) NaOH, (3) Ca(OH)2, (4) NH4OH, and (5) FH. The diets were fed 141 days including a 21-day adaptation period. Sodium hydroxide and Ca(OH)2 treatments decreased (P < 0.05) the organic matter concentration while the NH4OH increased (P < 0.05) the nitrogen level of the straw. Alkali treatments decreased (P < 0.05) the acid detergent fiber (ADF) and increased (P < 0.05) the hemicellulose contents of the straw compared to the water treatment. There were no significant (P > 0.05) differences among final weights and average daily gain of animals fed alkali treated forage and those fed fescue hay. Average dry matter intake and feed:grain ratio did not differ (P > 0.05) among treatments. Also, alkali treatments increased (P < 0.05) carcass weight compared the water treatment, whereas other carcass characteristics did not differ (P > 0.05) among treatments. Cattle fed the NH4OH treated SBS had the highest (P < 0.05) plasma urea-N (PUN) and ruminal ammonia-N concentrations than those fed the other treatments. Plasma urea-N did not differ (P > 0.05) among cattle fed SBS treated with NaOH, Ca(OH)2 or water and those fed FH diets. Ruminal ammonia-N concentrations were the lowest (P < 0.05) for cattle fed NaOH treated SBS. Ruminal pH value was the lowest (P < 0.05) for cattle fed the ensiled control compared to the other treatment groups. Alkali treatments did not (P > 0.05) affect the molar concentrations of VFAs. Molar proportion of acetate was higher (P < 0.05) for animals fed NaOH treated SBS than for those fed the water treatment. Molar proportion of propionate, butyrate, valerate, as well as acetate:propionate ratio did not differ (P > 0.05) among treatments.

Effect of the β-adrenergic agonist cimaterol and dietary protein level on fat young sheep given diets containing submaintenance levels of dietary energy

AbstractThirty Suffolk cross wether sheep aged about 12 months and weighing 57 kg on average were used. They had been given previously a high energy diet to produce a fat body condition and average condition score of 3·7. Animals were allocated to an initial slaughter group (IS) or to four dietary treatment groups (UL, UH, CL and CH) based on sugar-beet feed (L) or white-fish meal (H) supplemented with chopped straw and pelleted, without (UL and UH) or with (CL and CH) the β-adrenergic agonist cimaterol, to provide an estimated 20 g (L) or 130 g (H) rumen undegradable protein per kg dry matter (DM). The sheep were offered 0·3 kg of the appropriate pelleted diet in addition to 200 to 400 g of chopped barley straw to provide proportionately 0·7 of the estimated metabolizable energy requirement for maintenance and, where appropriate, 2·5 mg cimaterol per day. Comparisons were made for the main effects of dietary protein intake and cimaterol and interactions between dietary protein and cimaterol.The animals on dietary treatments were slaughtered after 49 days. The animals exhibited variable reductions in live weight and weights of carcass and non-carcass components in comparison with the IS group and in response to restricted dietary energy intake. The only effect due to the elevated dietary protein provision was a smaller loss in live weight compared with the low protein diet. In contrast, compared with responses recorded in its absence, treatment with cimaterol resulted in significantly greater values for weights of cold carcass, cross-sectional area o/m. longissimus dorsi and weights of DM, crude protein and ash in the carcass with significantly smaller weights for raw fleece. In comparison with the IS group, significantly smaller changes due to cimaterol were recorded for the weights of carcass crude protein and ash. Cimaterol treatment significantly increased the weight loss of fat in the carcass and in the perirenal and retroperitoneal, but not omental, depots as components of fleece-free non-carcass fat which was also significantly reduced in total. Interactions suggested that losses in carcass weight and DM in the presence of cimaterol were less and gains in carcass protein and ash greater, on the high than on the low protein diet. The results suggest that under conditions of energy undernutrition cimaterol may induce smaller losses or larger gains in carcass but not non-carcass, crude protein at the expense of fat depletion in carcass and non-carcass fat depots.

Influence of floor space allowance and access sites to feed trough on the production of calves and young bulls and on the carcass and meat quality of young bulls

One‐hundred‐and‐twenty Danish Friesian (DF) bull calves were used in a 3 × 2 factorial experiment with three floor space allowances in pens with fully slatted floor and two feeding‐trough arrangements. The floor space per animal was 1.4 m2 (group L), 1.7 m2 (group M), and 2.5 m2 (group H) from approximately 100 kg to about 300 kg live weight (period I). From approximately 300 kg until slaughter at 460 kg live weight (period II), the space allowance was increased by about 25% to 1.8 m2, 2.2 m2 and 3.1 m2 per animal, respectively. The concentrate was fed ad libitum in troughs with five eating places per pen (5 places/5 animals) or in one self‐feeder per pen (1 place/5 animals). Besides concentrate, all the animals were fed chopped barley straw ad libitum in a separate trough. Increased floor space allowance did not affect daily feed intake in either period I or period II. An increased space allowance from L to M and H increased the growth rate in both period I (1357, 1402 and 1429 g/day; P = 0.05) and period II (1193, 1258 and 1340 g/day; P = 0.14). Correspondingly, the feed conversion ratio expressed as Scandinavian Feed Units (SFU) per kg gain was decreased in period I (4.03, 3.75 and 3.84; P = 0.01) and period II (6.62, 6.21 and 6.04; P= 0.l7). In the full experimental period, the average carcass gain was 665, 687 and 719 g/day for group L, M and H, respectively (P = 0.05); SFU per kg carcass gain was 9.92, 9.33 and 9.15 (P = 0.02). Floor space allowance did not significantly affect dressing percentage, EUROP classification (conformation, fatness), carcass composition or meat quality (colour, pigment, intramuscular fat, shear force value). The number of eating places did not significantly affect any of the observed traits.

Comparison of high starch and high fibre diets and the development of subclinical laminitis syndrome in dairy heifers

Subclinical laminitis syndrome is associated with the appearance of haemorrhages in the sole and white line (Vermunt 1992). Feeding diets with a high proportion of concentrates to forage has been associated with an increased severity or incidence of sole haemorrhages (Weaver 1979; Livesey and Fleming 1984). It is widely accepted that using high levels of starchy feed ingredients may increase the risk or severity of subclinical laminitis syndrome. This experiment was designed to study the development of subclinical laminitis syndrome by feeding diets which differed in starch and fibre content when animals were bedded on chopped straw or wood shavings.A total of 40 Holstein heifers were divided into 4 groups in a 2 x 2 factorial experiment. The duration of the study was from shortly before calving until 12 weeks after calving. Heifers were housed in cubicles on rubber mats with either chopped straw or wood shavings as bedding.

The dacron bag technique for comparing rumen degradability of untreated and ammonia-treated barley straw – effect of particle size and degree of replication

SUMMARYSix rumen-fistulated steers were studied over six periods of 3 days at Reading University's Animal Production Research Unit. In each period, eight dacron bags comprising two replicates of the 22 factorial treatment set consisting of untreated and NH3-treated barley straw in chopped (12–54 mm) or ground (2·5 mm screen) form were placed in the rumen of each steer. Bags were left in the rumen for a given time which was one of the set 6, 9, 15, 24, 48, 72 h. Percentage dry matter (DM) disappearance from dacron bags was consistently higher for NH3-treated than untreated straw and higher for ground than chopped straw. Analysis of variance gave F ratios for period and steer which were non-significant but of similar size, showing that using fewer animals could be compensated for by using more periods. Percentage DM disappearance as a function of time was well described by the model y = a — beet. The parameter defining rate of disappearance c, was similar for the four forms of straw. Differences between straws occurred in values of a (potential degradability) and b suggesting that physical form of material put into dacron bags needs standardizing if absolute values of a are to be used (e.g. for predicting roughage intake). Experimental designs need further research.

Using beans (vicia faba) in a “barley beef” system for finishing bulls

Simplifying rations and using home grown ingredients can reduce costs of production and, provided productivity is maintained, increase profit. The objective of this experiment was to determine the performance of weaned suckled bull calves on a ration containing field beans (vicia faba), rolled barley, molasses and vitamins and minerals; the ad libitum straw intake was also examined.Twelve Limousin x (Hereford x Friesian) bull calves, 9 months old, were individually fed through two Callan-Broadbent doors, one for the concentrate ration and the other for chopped straw. Wood shavings were used for bedding. The two treatments, fed ad libitumfor 63 days were, barley/ rapeseed meal (B/RSM) and barley/ beans (B/E) and contained 153 ± 5.0 and 166 ± 8.4 g/kg DM CP and 12.6 ± 0.16 and 12.9 ± 0.17 MJ ME/ kg DM respectively.

Using beans (vicia faba) in a “barley beef” system for finishing bulls

Simplifying rations and using home grown ingredients can reduce costs of production and, provided productivity is maintained, increase profit. The objective of this experiment was to determine the performance of weaned suckled bull calves on a ration containing field beans (vicia faba), rolled barley, molasses and vitamins and minerals; the ad libitum straw intake was also examined.Twelve Limousin x (Hereford x Friesian) bull calves, 9 months old, were individually fed through two Callan-Broadbent doors, one for the concentrate ration and the other for chopped straw. Wood shavings were used for bedding. The two treatments, fed ad libitumfor 63 days were, barley/ rapeseed meal (B/RSM) and barley/ beans (B/E) and contained 153 ± 5.0 and 166 ± 8.4 g/kg DM CP and 12.6 ± 0.16 and 12.9 ± 0.17 MJ ME/ kg DM respectively.

Effects of methods of cereal straw disposal, seedbed preparation and sowing method on the establishment, yield and oil content of winter oilseed rape (Brassica napus)

SUMMARYIn the first of two series of experiments the effects of barley straw disposal by burning, chopping and spreading or baling and removing on winter oilseed rape were tested after seedbed preparation either by ploughing in the residue or incorporation in the soil by tine cultivation. These treatments were compared in four field experiments on silty clay loam soils at Rothamsted, UK from 1986 to 1989. The winter rape was either sown in late August or mid-September in seedbeds where either none or 50 kg N/ha had been applied.In the first season, August-sown rape was successfully established after tine cultivation but very dry conditions prevented seedbed preparation after ploughing, consequently all ploughed treatments were sown in September. Continuing dry conditions delayed emergence of the September-sown crop, the resultant small rape seedlings suffered substantial winter kill in some treatments during a period of abnormally low temperatures. Yield from the August-sown treatments was large (c. 40 t/ha) and showed no effect of straw disposal treatment or additional seedbed N. The yield of the September-sown crop was influenced by the amount of winter kill sustained; the smallest yields resulted from tine incorporation, and the largest after ploughing, where they approached those of the early sown crop.In the following three seasons more plants emerged from September than from August sowings. The application of seedbed N increased the plant population of the August-sown crop where the straw had been burnt. Plant losses over winter ranged from 15 to 20% and were unaffected by straw disposal treatment. There were significant differences in yield resulting from season and sowing date. Incorporating chopped straw by tine cultivation significantly decreased yield which, coupled with a lower oil content in the September-sown crop, gave a significantly smaller oil yield.In a second series of field experiments from 1987 to 1989, the effects of improving the timeliness of rape establishment after winter wheat by broadcasting rape seed into standing wheat was compared with conventional sowing after preparing a post-harvest seedbed. After cereal harvest, straw was disposed of either by baling and removing or chopping and spreading over the rape seed. The application of 50 kg N/ha to the stubble or seedbed was also tested, as was the effect of increasing the seed rate from 8 to 16 kg/ha in two seasons.There were always fewer plants established from broadcasting than from drilling. Generally there were fewer winter losses from broadcast seed than from drilled. Applying N to seedbed or stubble had no effect on plant population or survival except where 16 kg/ha seed was sown in 1989 and increased yield in two of the three seasons.In spite of a smaller plant population from broadcast seed, yields were often larger from broadcast than drilled treatments. On average broadcasting the seed and baling the straw gave the largest yield although this was significant only in 1989.

Effects of substituting feather meal for soybean meal on ruminal fiber fermentation and lamb and wool growth.

Our objective was to evaluate the effects of substituting feather meal (FM) for soybean meal (SBM) on ruminal fiber fermentation, lamb gain, blood metabolite profiles, and wool growth. A SBM supplement was formulated, and FM replaced either 33% (33FM), 66% (66FM), or 100% (FMS) of the SBM protein. Four ruminally cannulated wethers were used in a 4 x 4 Latin square design to study in situ ruminal digestion. Wethers were limit-fed barley straw and fed the supplements once daily. Ruminal NH3 N concentrations reflected a sampling time x protein source interaction (P < .01). Within sampling times, ruminal NH3 N concentrations decreased linearly (P < .05) as FM replaced soybean meal. Cubic (0 h; P < .10) and quadratic (24 h; P < .05) responses also were noted for ruminal NH3 N concentration. Substitution of FM for SBM had no effect (P > .10) on rate and extent of straw NDF disappearance. A 56-d feeding trial was conducted using 28 wether lambs (n = 7 per treatment; initial BW 32.3 kg). Wethers were individually fed chopped barley straw and one of the four supplements described previously. Linear increases (P < .05) in BW gain and serum total protein concentration were observed as FM replaced SBM. Wool fiber diameter and sulfur content did not differ (P > .10) among treatments. These data suggest that FM can be substituted for SBM in protein supplements fed to sheep consuming low-quality roughages at a maintenance level of ME intake.

Long-term experiment with straw management, stubble cultivation, autumn and spring ploughing on a clay soil in S.E. Norway

Autumn vs. spring ploughing, stubble cultivation and straw management were investigated in a factorial field experiment on a clay loam at Tune in S.E. Norway. The experiment was started in the autumn of 1963 and was completed in the aut3mn of 1984. The main crops were barley ( Hordeum vulgare L.) and oats ( Avena sativa L.). Autumn ploughing gave significantly higher yields, 420 kg ha −1 higher on average, than spring ploughing. The combination spring ploughing/no stubble cultivation/incorporated chopped straw treatment gave a yield decrease of 608 kg ha −1 year −1 as compared with autumn ploughing/no stubble cultivation/burnt straw. Incorporation of straw by stubble cultivation in combination with autumn ploughing was the best management practice as far as yields are concerned. The seedbed in spring was finer in the autumn ploughed soil because of the effect of freezing and thawing. Stubble cultivation had little effect when the soil was ploughed in autumn. To avoid yield depression after spring ploughing it was important to incorporate the straw by stubble cultivation in autumn. Stubble cultivation depressed the infestation of couch grass ( Elytrigia repens L. Nevski). Burning straw resulted in higher yields when the soil was ploughed in spring and also reduced infestation of weeds. The positive effect of burning on yield was especially clear on spring ploughed soil without stubble cultivation. After 19 years of ploughing in cereal straw, aggregate stability and organic matter content in the soil had increased as compared with burning. The increase in organic matter was 0.3%. Other physical properties were not influenced by straw management.

The effect of feeding different sources of crude fibre during pregnancy on the reproductive performance of sows

ABSTRACTA long-term experiment was designed to study the effect of feeding different sources of crude fibre during pregnancy on the reproductive performance of sows. The four treatments imposed during pregnancy were: C, a control compound diet; CS, the same control diet with additional chopped straw (0·2 kg/day); CM, the same control diet in which 0·25 kg was replaced daily by 1·5 kg maize silage; and CFR, a compound diet with a higher crude fibre content. In total 567 sows were used. On the treatments C, CM, CS and CFR the number of sows was 147, 142, 147 and 133 respectively. The sows remained on the experiment for five successive parities on a treatment or until the moment of culling. Feeding levels were about 32 MJ digestible energy (DE) per day during the first months of pregnancy and about 40 MJ DE per day in the last month of pregnancy. During lactation the feeding level ranged between 75 and 90 MJ DE per day.In sows giving birth to five litters, the effect of parity was calculated irrespective of the treatments. The optimum litter size was observed in the fourth litter and the percentage of successful services within 10 days post weaning stabilized after the third parity. The live weight of the sows increased gradually up to the fifth parity.Compared with the sows on the control treatment the proportional changes in consumption of the sows on the other treatments were: 0·45 more crude fibre, up to 0·02 more digestible energy and up to 0·06 less digestible protein.There were only slight differences in reproductive performance. The mean number of weaned piglets per sow per year were 19·7, 19·3, 20·1 and 20·2, respectively for the treatments C, CM, CS and CFR. Higher piglet birth weights were observed for sows on the CM treatment and a higher proportion of the culled sows had leg disorders. On the CS treatment a higher number of weaned piglets per litter was observed and this was due to the higher number of piglets born and lower piglet mortality during lactation. The sows on this treatment tended to have more difficulty in becoming pregnant after the third and fourth parities. The sows on the CFR treatment had the highest body weights and had a higher number of litters per year mainly due to lower numbers returning to service and less nonproductive days. The results from this experiment gave no clear evidence that either the inclusion of roughage or a higher crude fibre content in the diet improved reproductive performance.

Partial Replacement of Alfalfa Hay with Chopped Wheat Straw in Diets for Lactating Dairy Cows

Two trials were conducted to determine the effect of substituting chopped wheat straw (untreated or ammoniated) for part of the alfalfa hay in rations for lactating dairy cows. As fed, all rations contained 45% forage. In trial 1, three different diets were fed: one-half of the forage was long alfalfa hay in each diet and the remainder was either chopped alfalfa hay, untreated chopped straw, or ammoniated chopped straw. In trial 2, the same three diets were fed, and a fourth diet was included in which all forage was long alfalfa hay. Production responses were consistent across both experiments. Neither DM intake (18 kg/d) nor milk yield (26 kg/d) was affected by diet. Milk fat percentage was increased by substituting straw in the diet and, as a result, yield of 3.5% FCM was increased. Protein and SNF content of the milk generally were not different among treatments. Ruminal acetate increased and propionate decreased when straw was added to the diet. Other than an increase in BW in trial 1, treating wheat straw with ammonia did not affect any of the traits studied. Under the conditions of this study, substitution of chopped straw for 50% of the alfalfa hay in high grain diets for lactating dairy cows maintained milk yields and increased production of FCM because of higher milk fat percentage. Low milk fat creased production of FCM because of on the alfalfa hay diets was related to its lower ADF content and reduced forage particle size compared with the straw diets. Ammoniation of the wheat straw did not affect production responses.

Straw incorporation and tillage methods: Straw decomposition, denitrification and growth and yield of winter barley

A field experiment was conducted over four seasons on a clay loam (24% clay in topsoil) in Scotland. Straw incorporation with conventional ploughing, shallow ploughing, rotary and tine cultivation was investigated for continuous winter barley. Residue treatments were either chopped straw plus stubble or stubble only. Incorporation depths ranged from 0–100 to 0–300 mm. Where stubble only was incorporated, mean grain yields were greater with ploughing (7·2 t/ha) than with shallow rotary cultivation (6·3 t/ha). Where straw and stubble were incorporated, mean grain yields were greater with ploughing (7·6 t/ha) than with non-ploughing (mean over six treatments, 7.0 t/ha). Non-ploughing incorporation with deep (200 mm) rotary cultivators gave a greater mean grain yield (7·5 t/ha) than with shallow (<150 mm) tine or rotary cultivators (6.8 t/ha). Low yields with shallow non-ploughing incorporation were associated with poor crop survival and growth vigour over winter. These effects were related to waterlogging, which caused the crop to yellow and soil nitrogen to be released as nitrous oxide, and to the phytotoxic effects of surface straw which appeared in late autumn. Irrespective of residue treatment, no improvement in yield or soil fertility resulted from ploughing deeper than 100–150 mm. Ploughing distributed residues more uniformly with depth than non-ploughing, which concentrated them near the surface. Residue incorporated near the soil surface decomposed at the same rate as that buried more deeply by conventional ploughing. The most reliable method of minimizing primary tillage for incorporation and for preserving favourable soil conditions was shallow ploughing. Minimizing secondary cultivations and substituting broadcasting for drilling reduced compaction and reduced inputs at minimum risk to the crop. Broadcasting seed also resulted in a small yield advantage over drilling.

Straw incorporation and tillage methods: Straw decomposition, denitrification and growth and yield of winter barley

A field experiment was conducted over four seasons on a clay loam (24% clay in topsoil) in Scotland. Straw incorporation with conventional ploughing, shallow ploughing, rotary and tine cultivation was investigated for continuous winter barley. Residue treatments were either chopped straw plus stubble or stubble only. Incorporation depths ranged from 0–100 to 0–300 mm. Where stubble only was incorporated, mean grain yields were greater with ploughing (7·2 t/ha) than with shallow rotary cultivation (6·3 t/ha). Where straw and stubble were incorporated, mean grain yields were greater with ploughing (7·6 t/ha) than with non-ploughing (mean over six treatments, 7.0 t/ha). Non-ploughing incorporation with deep (200 mm) rotary cultivators gave a greater mean grain yield (7·5 t/ha) than with shallow ( Irrespective of residue treatment, no improvement in yield or soil fertility resulted from ploughing deeper than 100–150 mm. Ploughing distributed residues more uniformly with depth than non-ploughing, which concentrated them near the surface. Residue incorporated near the soil surface decomposed at the same rate as that buried more deeply by conventional ploughing. The most reliable method of minimizing primary tillage for incorporation and for preserving favourable soil conditions was shallow ploughing. Minimizing secondary cultivations and substituting broadcasting for drilling reduced compaction and reduced inputs at minimum risk to the crop. Broadcasting seed also resulted in a small yield advantage over drilling.

Supplementation of grazing dairy cows with a brewers grains/treated straw mixture

Supplementary feeding of grazing dairy cows is often uneconomic, and whilst supplementation with silage (buffer feeding) can be worthwhile, this often leads to a depletion of winter forage stores. In this study, a mixture of brewers grains and treated straw was used as a supplement. Offered as a 1:1 mixture in the dry matter (DM), it is a purchased substitute for grass silage, having a similar cost, and similar metabolisable energy (ME) and crude protein (CP) contents. The high seasonality adjustments to milk price in mid-late season make supplementation potentially worthwhile.Experiments were carried out from April to September in 1988 and 1989, which had moderate and very low rainfall respectively. Each year 20 British Friesian cows which calved December to March (1988 experiment) and February-April (1989) were allocated at random to either treatment B or C. In B, the cows were offered a 1:1 mixture (DM basis) of brewers grains and NaOH treated chopped barley straw for 60 minutes after morning milking. In C, the cows received no supplement. Both groups were fed 1.0 kg/day of concentrates in the milking parlour. Due to the severe drought in 1989, concentrate feeding was increased to 5.0 kg/day for all cows during the last 4 weeks of the experiment. Also, urea-treated whole crop wheat was fed at a level of 2.5 kg DM/day during the last 7 days.