Improving utilization of crop residues. Evaluation of two chemicals used to improve digestibility of crop residues

Two chemical treatments involving chelating metal caustic swelling (CMCS) and sodium hydroxide (NaOH) were evaluated for their ability to affect in vitro dry matter and in vitro cellulose disappearance (IVDMD and IVCD, respectively), dry matter disappearance in sacco and the chemical composition of two low-quality crop residues, cornstalks (CS) and soya bean residue (SBR). At $\text{chemical}\text{substrate}$ ratios ranging from 0.25:1 to 5:1, linear increases in IVCD of both roughages were noted. Improvements in IVCD of CS and SBR were noted at 1:1, 3:1 and 5:1$\text{chemical}\text{substrate}$ ratios, regardless of whether the treated roughages were used immediately after treatment (fresh basis) or preserved by drying or freezing. Decreased concentrations of neutral detergent fibre (NDF), acid detergent fibre (ADF), acid detergent lignin (ADL) and crude protein (CP) resulted from chemical treatment. No effects of the water component of the solvent solutions were observed. Dry matter disappearance in sacco of CMCS- and NaOH-treated roughages was increased at all $\text{chemical}\text{substrate}$ ratios tested. Treatment of either roughage with CMCS resulted in greater digestibility in sacco than did treatment with NaOH. Treatment of CS with CMCS resulted in higher rates of digestion than did treatment with NaOH. No differences in rates of digestion of SBR were noted between chemicals. Both chemicals were more effective in improving digestibility of CS than of SBR.     

Review article: The alkali treatment of straws

The Beckmann method of alkali treatment consists of soaking straw in dilute alkali solutions for 24 hours and then washing it with clean water. Straw digestibility is increased from about 40 to about 70%. While this process has been known for 50 years, it has not been much used because treatment costs are too high. Also, it cannot be industrialised. The spray process, in which the straw is wetted with an alkali solution (Wilson and Pigden, 1964) is an improvement from both points of view, but poses nutritional problems since straw is not washed after treatment. So great is the potential, however, that within the last seven years nearly 100 research reports have been published on the production and use of spray-treated straw. These reports are reviewed in this article.Straws are poorly digested by ruminants because of their high cell-wall content. Alkali treatment disrupts the cell-wall by dissolving hemicellulose, lignin and silica, by hydrolysing uronic and acetic acid esters and by swelling cellulose. Digestibility in vitro increases from about 40 to about 80% with $\text{10}\text{g NaOH}\text{100}\text{g straw}$. Equally large increases are not, however, obtained in vivo because of unreacted alkali and/or high sodium concentration. Several hypotheses concerning the depression of digestibility in vivo are reviewed. In general $\text{3–6}\text{g NaOH}\text{100}\text{g straw}$ is the optimum. For maximum effectiveness the volume of the alkali solution must be between 50 and $\text{200}\text{ml}\text{100}\text{g straw}$. The usefulness of neutralising unreacted alkali has not yet been determined. Crop and industrial residues with lower initial digestibility than straw (e.g. paddy hulls, bagasse and some types of sawdust) are usually still too poor after treatment (digestibility 30–50%) to be useful feeds. Pressure and temperature increase the effectiveness of alkali, but add to the cost of treatment. The pelleting of treated straws probably increases the effectiveness of alkali treatment. The length of time treated straw is allowed to “cure” before being fed does not affect its digestibility. Chemicals other than NaOH, like chlorine, ammonia and peroxides, are also effective in treating straws but are more expensive and/or more difficult to apply.Animal feeding experiments with sprayed straw have shown its utility for livestock normally fed poor straw diets, in high concentrate diets for growing, finishing and milking stock, and as an extender of silage. The factors affecting the degree of improvement to be expected in digestibility, growth and production from the treatment of straw need to be identified and studied.In spite of its high pH and Na content, sprayed straw has not been found to cause any health problems in livestock when treatment is in the range of 3–8 g NaOH/100 g straw. The extra sodium is excreted in the urine. Water intake and urine volume increase. Milk composition is unaffected.Several factories producing alkali spray-treated straw-based diets in pelleted form are already in operation in Europe. The process is briefly described.     

Effect of storage and processing of barley on its utilization by pigs and rats

Grain of 16.7% moisture content was stored in exprimental silos by four methods. These were: (1) controlled environment (a sealed container); (2) addition of 1% acid mixture (60 acetic acid: 40 propionic acid); (3) addition of 3.2% sodium hydroxide in a 32% solution to give 21.8% moisture content; and (4) air-dried (82°C) to 13.3% moisture.After 9 months storage, apparent digestibility of dry matter, nitrogen and neutral detergent fibre was measured with pigs, while true protein digestiblity, biological value and net protein utilization were measured with rats.With pigs, there was no treatment effect on dry matter digestibility, but neutral detergent fibre digestibility was reduced in the dried barley. The apparent protein digestibility was markedly depressed to 44.5% for the alkali-treated grain compared with a mean of 65.1% for the other treatments (P < 0.001). In the rat trial, true digestibility of nitrogen and biological value were severely depressed (P < 0.001) by alkali treatment, but differences between the other treatments were relatively small.     

Ensiled alkali-treated straw. I. Effect of level and type of alkali on the composition and digestibility in vitro of ensiled barley straw

In three experiments barley straw chopped to 5 cm nominal particle length was ensiled in laboratory silos for 90 days after treatment with alkali. In the first two experiments, NaOH was added at 0, 1.05, 2.10, 3.15 or 4.20 g per 100 g straw dry matter (DM) (Experiment 1) or at 0, 2.5, 5.0, 7.5 and 10.0 g per 100 g straw DM (Experiment 2) in solutions at either 60 ml or 120 ml solution per 100 g straw DM. Digestibility in vitro of organic matter (OM) and digestible OM in DM (DOMD) increased with increasing level of NaOH. The effect of volume of solution on digestibility was small. The pH of the straws decreased during storage. The content of neutral detergent fibre decreased as the level of NaOH increased, but there was relatively little change in the contents of acid detergent fibre or acid detergent lignin. Lactate and acetate were detected in all silages, and butyrate was present in silages made from straws treated with less than 5 g NaOH per 100 g straw DM. On opening the silos little moulding was seen and the temperature of the straws remained close to ambient in both experiments throughout 16 days of subsequent exposure to air.In the third experiment, the comparative effects of Ca(OH)₂ and KOH were studied alone and in combination ($\text{50}\text{50}$ by weight) with NaOH. KOH mixed with NaOH gave levels of DOMD in vitro similar to those obtained with NaOH alone. Ca(OH)₂, whilst improving DOMD, was slightly less effective than the other alkalis.The optimum level of alkali for the treatment of barley straw prior to ensiling appeared to be 7.5 g/100 g straw DM. At this level of addition, DOMD in vitro would be expected to be about 65%. Ca(OH)₂ is worth further attention as an alternative to NaOH.     

Alkali treatment of straw for ruminants. I. Utilization of complete diets containing straw by beef cattle

In the first of two experiments, 40 Friesian steers weighing initially 300 kg were fattened on diets containing barley and soya bean meal alone (C) or with inclusions of 40% untreated straw (WS₄₀) or 40 or 60% alkali-treated straw (AS₄₀ and AS₆₀). The straw was coarsely milled into a horizontal mixer, where sodium hydroxide was applied as a 16% solution providing $\text{80}\text{kg NaOH}\text{t straw dry matter (DM)}$. Intakes of DM (kg/d) were: C, 7.88; AS₄₀, 9.67; AS₆₀, 9.23; WS₄₀, 8.60, and empty body weight gains (kg/d, in the same order) were 1.16, 1.03, 0.82 and 0.78.In the second experiment there were four diets, all containing 60% straw and 40% concentrates. The straw was coarsely milled (M) or chopped by forage harvester (C), and treated with alkali (A) or untreated (U). In a trial of latin square design, intake (kg DM/d) was; MU, 7.77; MA, 10.37; CU, 7.44; CA, 10.12. In a longer trial with five steers per diet, liveweight gains (kg/d, in the same order) were 0.70, 1.09, 0.71 and 1.18. The digestibility of DM for the four diets was 60.0, 72.7, 60.3 and 72.0%.The utilization of the energy of the diets, and the economic value of alkali treatment, are discussed.     

Performance of Growing-Finishing Pigs Fed Diets Based on Normal or Low Viscosity Rye Fed With and Without Enzyme Supplementation

One hundred and forty crossbred pigs (Pig Improvement Canada Ltd, Acme Alberta), weighing an average of 21.5 + 3.6kg, were assigned on the basis of sex, weight and litter to one of five dietary treatments. The control diet was barley-based, while in the remaining four treatments, the grain component consisted of either normal or low viscosity rye fed with or without pentosanase. Digestibility coefficients for dry matter, crude protein and gross energy were significantly ( P = 0.0001) higher for the rye-based diets than the barley based diet. There were no differences in digestibility coefficients between normal and low viscosity diets or between diets supplemented or unsupplemented with pentosanase. Over the entire experimental period (21.5 to 100.7kg), pigs fed the normal viscosity rye gained better ( P = 0.001) and had a higher daily intake ( P = 0.001) than pigs fed the low viscosity rye. Pigs fed the low viscosity rye tended to gain slower than pigs fed barley and with lower intake while pigs fed the normal viscosity rye had similar gains and intake to the pigs fed barley. Enzyme supplementation failed to improve pig performance. Males had higher gains and intake than females ( P < 0.05). Enzyme supplementation, rye viscosity or choice of cereal grain had no effect on any of the carcass traits measured. In conclusion, the results of the present experiment indicate that rye is a good alternative to barley for use in growing-finishing rations and becomes increasing attractive as the age of the pig increases. Breeding efforts directed towards reducing the viscosity of rye are unlikely to be successful in improving the nutritive value of rye for swine.     

Estimation of the digestibility of low-quality hays by cattle from measurements made with sheep

Seventeen sets of apparent digestibility data derived from 10 experiments, in which both cattle and sheep had been fed on the same hays, were examined. The study was restricted to low-quality hays of less than 60% apparent digestibility of dry matter. On average, digestibility was higher for cattle than for sheep, and the difference was greatest with the samples of lowest digestibility. A linear equation found to describe best the relationship between the digestibility of hays by cattle and sheep was:

$\text{y = 0.673 x + 20.3}$

where y = digestibility of hay to cattle (%) and x = digestibility to sheep (%) (r = 0.843; S_y.x, ± 3.41; standard error of the slope, ± 0.111). This equation may be used to correct apparent digestibility values of 60% or less measured with sheep, or estimated in vitro with the use of sheep standards, if the digestibility data are to be applied to cattle.     

Simplified method for alkali treatment of low-quality roughages for use by small-holders in developing countries

The method described is a modification of the soaking procedure of Beckmann and of Torgrimsby. As the effluent NaOH solution is successively replenished and re-used many times before being discarded, pollution is minimised. Furthermore, the amounts of water and alkali consumed are smaller than with the Beckmann method, and the same container is used for all treatments and washing. The method is adaptable to small-scale farming.In Experiment 1, Cynodon hay was treated with 0, 50 or 100 kg NaOH/tonne dry matter (DM), by a modification of the Beckmann method. Significant (P < 0.01) improvements in digestibility of dry matter (DM), organic matter (OM), and cell wall constituents (CWC) were obtained, and voluntary feed intake was raised significantly (P < 0.01).In Experiment 2, both NaOH and Ca(OH)₂ treatments at 0, 50, 100 and 150 kg alkali/tonne DM of maize stover, significantly (P < 0.01) increased DM and OM digestibility, but the response was greater with NaOH. A combination of NaOH and Ca(OH)₂ treatments had no consistent effect on digestibility, but the trend was a decline in digestibility when Ca(OH)₂ was applied at high rates of 100 and 150 kg Ca(OH)₂/tonne DM. The recovery of DM increased with Ca(OH)₂ treatment, but decreased with NaOH.In Experiment 3, the treatment of maize stover with 0, 25 or 50 kg Ca(OH)₂/tonne DM, in combination with 0, 100 or 150 kg NaOH/tonne DM, significantly (P < 0.01) decreased DM, OM, and CWC digestibility below that achieved by NaOH alone.It is concluded that with the modified method an initial allowance of 100–150 kg NaOH/tonne DM of stover and replenishment of 40–60 kg NaOH/tonne DM is optimal.     

Fiber digestibility in juvenile Galapagos tortoises (Geochelone nigra) and implications for the development of captive animals

Digestive strategies have been recognized to be a key factor for healthy growth in juvenile Galapagos giant tortoises (Geochelone nigra). The aim of present study was to investigate digestive coefficients with special regard to fiber fractions. Four captive bred Galapagos giant tortoises 4–5 years of age were fed a controlled diet for 32 days. The diet consisted of 77% hay, 15% tortoise pellets, and 8% apples on a dry matter basis. On a dry matter basis diet analysis showed: 95.7% organic matter, 11.3% crude protein, 20.5% crude fiber, 22.6% acid detergent fiber, 5.0% acid detergent lignin, and 17.6% cellulose. Based on total fecal collection during 7 days average dry matter digestibilities were calculated: 65% for dry matter, 67% for organic matter, 63% for crude protein, 55% for crude fiber, 49% for acid detergent fiber, 41% for acid detergent lignin, 54% for cellulose. An increase in crude fiber content resulted in a reduced digestibility in comparative evaluations of data for different tortoise species, and in a comparison of tortoises and mammalian hindgut fermenters. Compared to some mammalian hindgut‐fermenting herbivore species (domestic horses, Asian elephants, Indian rhinoceroses) on a diet of hay and concentrates, the juvenile Galapagos giant tortoises showed a digestion of similar efficiency. If a reduction in dietary digestibility is warranted in juvenile Galapagos giant tortoises, it is concluded that dietary fiber levels should be increased and it is proposed that crude fiber levels of 30–40% on a dry matter basis should be achieved. Zoo Biol 24:185–191, 2005. © 2005 Wiley‐Liss, Inc.     

The effect of silage additives containing formaldehyde on the fermentation of ryegrass ensiled at different dry matter levels and on the nutritive value of direct-cut silage

Ryegrass, harvested at the pre-ear emergence stage of growth, was ensiled in laboratory silos, either fresh (175 g dry matter kg^?1) or wilted to five DM levels ranging from 216–432 g DM kg^?1, with and without additive treatment. The additives used were “Sylade” containing sulphuric acid (15%) and formaldehyde (23%) applied at 4.6 l t^?1 and an “ADD-F” $\text{(85\%}\text{formic acid}\text{)}\text{formalin}$ mixture (7:3 by volume) applied at a similar rate (4.8 l t^?1). An additional treatment included application of the mixture at a constant rate related to the DM content of the ensiled crop (25 l t^?1 DM).In the untreated silages, the water-soluble carbohydrates (WSC) varied, respectively (over the DM range 175–432), from 0–32 g kg^?1 DM compared with 197-6 g kg^?1 DM for the “Sylade” treated silages and 256-50 g kg^?1 DM for the formic acid/formalin silages treated at an additive rate of 4.8 l t^?1. Corresponding ranges of protein N for the control and treatments (expressed as g kg^?1 total N) were 302–447, 624-502 and 620-505, respectively. When the formic acid/formalin additive was applied at a constant level related to the DM content of the crop, although the WSC content decreased with increasing DM (247-158 g kg^?1 DM), the protein N content (612 g kg^?1 total N) remained constant.Grass from the same field was ensiled fresh, treated with “ADD-F” at the rate of 3.4 l t^?1 fresh grass, $\text{“}\text{ADD-F}\text{”}\text{formalin}$ at the rate of 4.8 l t^?1 fresh grass and “Sylade” at the rate of 4.6 l t^?1 fresh grass. The silages were given to Suffolk-cross wether lambs in digestibility and intake trials. Digestibility coefficients of DM and energy of the silage treated with “Sylade” were significantly lower (P < 0.05) than those of the other three silages. The DM intakes of all the silages were high, ranging from 27.7 g kg^?1 live weight for the “Sylade” silage to 30.7 g kg^?1 live weight for the silage treated with $\text{“}\text{ADD-F}\text{”}\text{formalin}$. Live weight gains ranged from 200 g/day for the control silage to 267 g/day for the $\text{“}\text{ADD-F}\text{”}\text{formalin}$ silage.     

Digestibility of timothy hay by African elephants

Two juvenile, female African elephants (Loxodonta africana) were used in summer and winter trials to determine the apparent digestibility of timothy (Phleum pratense) hay. After 12–14 days of dietary adjustment, dry matter intake and fecal excretion were quantitatively measured for 7 days. Dry matter of timothy hay contained 8.6 and 7.7% crude protein, 57.3 and 44.0% acid detergent fiber, and 6.5 and 6.4% ash during the summer and winter trials, respectively. Estimates of apparent digestibility during summer and winter, respectively, were 39 and 35% for dry matter, 43 and 32% for gross energy (GE), 45 and 30% for crude protein (CP), and 36 and 24% for acid detergent fiber (ADF). While GE and CP digestibility estimates tended (P < .09) to be greater in the summer trial, only the digestibility of ADF was different (P < .05) between summer and winter. Dry matter intake was 1.4–1.6% of body weight (BW), providing an average of 144 kcal of digestible energy per kg BW^0.75. This value is similar to that (155 kcal per kg BW^0.75) used for estimating digestible energy requirements for maintenance of light-breed horses.     

Effects of linseed lipids fed as rolled seeds, extruded seeds or oil on organic matter and crude protein digestion in cows

Effects of fatty acids of linseed in different forms, on ruminal fermentation and digestibility were studied in dry cows fitted with ruminal and duodenal cannulas. Four diets based on maize silage, lucerne hay and concentrates (65/10/25 dry matter (DM)) were compared in a 4 × 4 Latin square design experiment where the diets were: control diet (C), diet RL supplied 75 g/kg DM rolled linseeds, diet EL supplied 75 g/kg DM extruded linseeds, and diet LO supplied 26 g/kg DM linseed oil and 49 g/kg DM linseed meal. The diets did not differ in total organic matter (OM) and fibre digestibility, in forestomach and intestinal OM digestibility, and in duodenal N flow. Microbial N duodenal flow tended to be lower for RL versus C diet (P<0.1). Extrusion did not reduce ruminal crude protein (CP) degradation in vivo and in situ. Volatile fatty acid concentration and pattern, and protozoa concentration in the rumen, did not vary among diets. Results confirm the absence of a negative effect of a moderate supply of linseed on rumen function, as well as no effect of extrusion on its ruminal CP degradability.     

Neocarzinostatin: Chemical characterization and partial structure of the non-protein chromophore

The molecular formula C₃₅H₃₅NO₁₂ (mol.wt. 661) is proposed for the biologically active chromophoric component of neocarzinostatin. The partial structure $\text{2}$ is proposed based on ${}^1\text{H}$ NMR and mass spectral data and consists, in part, of a 2,6-dideoxy-2-methylamino-galactose moiety and a naphthoic acid derivative. Special treatments required to obtain spectral data of the labile chromophore are described.     

Analysis of Covariation of Grain Yield and Dry Matter Yield for Breeding Dual Use Hybrid Rye

Winter rye (Secale cereale L.) is becoming increasingly important as substrate for biogas production in Central Europe. Dry matter yield has evolved as a breeding goal comparably important to the traditional grain yield. We analyzed the covariation between both traits and tested other agronomic traits for their correlation to dry matter yield that could be used for prediction of biomass yield. A set of 258 experimental hybrids were tested for dry matter yield harvested at late milk stage and grain yield harvested at full ripening at three to four locations in Germany in 2011 and 2012. We observed a wide range of dry matter yield (10–24 Mg ha^?1) and grain yield (6–15 Mg ha^?1) among testcross progenies. Genetic variances were significantly (P?<?0.01) different from zero for all traits. High entry-mean heritabilities (0.92–0.94) were found for plant height measurements and moderate heritabilities for grain and dry matter yield (0.52 and 0.49, respectively). Relative efficiencies for selection of dry matter yield estimated by second (EC 51–55) and third (EC 73) measurements of plant height were 1.24 and 0.98 respectively, compared to 0.52 for grain yield. Indirect selection for high dry matter yield using late plant height measurements should be successful. Using grain yield for indirect selection was less effective. The observed broad genetic variation for biomass yield in elite hybrid rye gives good prospects for the use as a resource of renewable energy. Plant height is a good predictor of dry matter yield but should be selected together with improved lodging resistance.     

Influence of barley grain particle size and treatment with citric acid on digestibility,ruminal fermentation and microbial protein synthesis in Holstein calves

Chemical and physical treatments of barley grain increase ruminally resistant starch and can improve the rumen fermentation pattern. The objective of the present study was to evaluate the effects of chemical (addition of citric acid, CA) and physical (grinding to two different particle sizes, PS) treatment of barley grain on performance, rumen fermentation, microbial protein yield in the rumen and selected blood metabolites in growing calves. In all, 28 male Holstein calves (172±5.1 kg initial BW) were used in a complete randomised design with a factorial arrangement of 2 barley grain particle sizes×2 levels of citric acid. The diets were as follows: (i) small PS (average 1200 µm) barley grain soaked in water (no CA addition); (ii) small PS barley grain soaked in a CA solution (adding 20 g CA/kg barley); (iii) large PS (average 2400 µm) barley grain soaked in water (no citric acid addition) and (iv) large PS barley grain soaked in a citric acid solution (adding 20 g CA/kg barley). Barley grain was then incorporated at 35% in a total mixed ration and fed to the calves for 11 weeks. Feeding small PS barley decreased feed intake (P=0.02) and average daily weight gain (P=0.01). The addition of CA to barley grain did not affect intake but increased weight gain (P<0.01) and improved feed to gain ratio (P=0.03). Digestibility of organic matter and NDF tended (P<0.10) to increase, whereas faecal scoring was improved (P=0.03) and the presence of undigested grain particles in faeces was reduced (P<0.01) with CA-treated barley grain. Glucose and urea concentrations were increased (P<0.01) in the blood of calves fed the CA-treated barley grain. Ruminal pH tended (P=0.08) to be decreased with more finely ground barley and was increased when barley grain was treated with CA. Total volatile fatty acid concentrations in the rumen did not differ among treatments (P>0.05). However, the molar proportion of propionate was increased (P=0.03) when barley was more finely ground, and that of acetate was increased (P=0.04) when CA was added to barley grain. The ruminal concentration of ammonia nitrogen was increased (P<0.01) and microbial nitrogen synthesis in the rumen tended to decrease by adding CA to barley. Treating barley grain with citric acid increased fibre digestibility of total mixed rations, attenuated the decrease in ruminal pH, and improved weight gain and feed efficiency in male Holstein growing calves fed a high-cereal diet (550 g cereal grain/kg diet).     

Novel nucleotides from E.coli isolated and partially characterized

Two new nucleotides have been found in the formic acid extracts of $\text{Escherichia}\text{coli}$, $\text{Clostridium}\text{botulinum}$, $\text{Bacillus}\text{subtilis}$ and $\text{Rhodospirillum}\text{rubrum}$ isolated during log phase growth. In $\text{E.}\text{coli}$ the compounds are present at all times during cell growth but increase in amount during interruption of aeration and transition to stationary phase. They migrate close to ppGpp during one dimensional chromatography on PEI cellulose but are clearly separated from ppGpp by paper chromatography. The compounds are unstable on PEI cellulose and purification was effected by chromatography on A25 Sephadex ion exchange columns. Preliminary characterization indicates that the predominant compound is a dinucleoside polyphosphate and that both compounds contain a modified adenosine nucleoside.     

Utilization of alkali-treated and neutralized wheat straw-based rations for growing goat kids

Six groups of six goat kids were fed individually for 168 days with wheat straw given various treatments: (1) control; (2) 33 g NaOH/kg straw; (3) 80 g NaOH/kg, partly neutralized with mineral acids; (4) mineral control for 80 g NaOH/kg; (5) 120 g NaOH/kg, partly neutralized with mineral acids, and (6) mineral control for 120 g NaOH/kg straw. The average weight gain was significantly superior (P< 0.05) and the efficiency of dry matter (DM) and energy utilization was the highest with the 80 g NaOH/kg straw treatment. This treatment also gave significantly higher (P<0.05) digestibility of DM, organic matter (OM), neutral detergent fibre (NDF), acid detergent fibre (ADF), nitrogen-free extract (NFE) and hemicellulose than the control and 33 g NaOH/kg straw treatments. Increasing levels of alkali decreased (P<0.05) the digestibility of crude protein (CP) and ether extract (EE). Digestible energy and nitrogen-corrected metabolisable energy (ME_n) (as a percentage of gross energy (GE)) were maximal with 80 g NaOH/kg. The pH value of rumen liquor was the same for the control and the 33 g NaOH/kg and 80 g NaOH/kg treatments, but significantly increased (P<0.05) with the 120 g NaOH/kg straw treatment. The mean values for rumen ammonia nitrogen (NH₃ -N) were the same for the control, the 33 g NaOH/kg, and mineral controls for 80 and 120 g NaOH/kg treatments, but 80 g NaOH and 120 g NaOH/kg straw gave significantly lower values. It is suggested that by partially neutralizing the residual alkali, 80 g NaOH/kg straw can give higher efficiency of energy utilization for growth and digestibility of nutrients compared with 33 g NaOH/kg or the untreated control group, and the extensive use of treated straw in the diets of animals of which a rapid rate of production is not demanded, may be advantageous.     

Altered motility of myometrium from estrous ewes after the regulation of estrus with progestagen or prostaglandin

The $\text{in}$$\text{vitro}$ motility of strips of myometrium was studied in estrous ewes after administration of melengestrol acetate (MGA), medroxyprogesterone acetate (MAP) or prostaglandin F_2α (PG) to regulate estrus. Ewes were killed during estrus, 2 to 4 days after the end of progestagen or PG treatment. The contractions of strips of myometrium were recorded by kymograph and compared to contractions of control ewes.Muscle relaxation was indicated by an interval of tracing that was nearly horizontal and close to the baseline. A major contraction was indicated by a sharp upward movement of the tracing pen and an interval of tracing above the baseline.Treating ewes with MAP by intravaginal sponge lengthened contraction time. Feeding MGA or MAP tended to shorten relaxation time, and injecting PG tended to both lengthen contraction time and shorten relaxation time. As a result of these effects, the proportion of time that myometrium spent in contraction averaged 74% for 42 ewes treated with progestagen or prostaglandin and 56% for 24 control ewes. These results indicate that treatments that inhibit sperm transport when used to regulate estrus also affect the nature of myometrial contractions $\text{in}$$\text{vitro}$.     

Utilization of alkali-treated grain. 2. Utilization by steers of diets based on hay or straw and mixed with either NaOH-treated or rolled barley

In the first of three experiments, Hereford cross steers were fed ad libitum from 325 kg to slaughter at 425 kg on diets containing 50% hay and 50% rolled or NaOH-treated (30 g/kg) barley. Liveweight gain and food conversion ratios were similar for the two groups (1.24 vs. 1.42 kg/day; 7.0 vs. 7.0 kg dry matter intake/kg gain, respectively). Dry matter and organic matter digestibility was significantly higher (P < 0.01) when the diet contained rolled, rather than NaOH-treated, barley. There were no significant differences in fibre digestibility (51.2 vs. 59.1%, respectively).In the second experiment, the optimum level of NaOH was determined for the treatment of barley when given with hay. The level of NaOH required to achieve a digestibility in whole barley similar to rolled barley was 40 g NaOH/kg, i.e., approximately 10 g/kg more than when NaOH-treated barley formed the sole component of the diet. Dry matter and organic matter digestibility increased linearly as the level of NaOH applied increased (P < 0.05) and tended to peak at 40 g NaOH/kg barley. Starch digestibility also increased linearly (P < 0.001). Fibre digestibility did not vary significantly between treatments.In the third experiment, the voluntary intake of straw by steers given rolled or NaOH-treated barley at two levels of supplementation was determined. The intake of straw was slightly, but not significantly, greater when NaOH-treated rather than rolled barley was used. The digestibility of dry matter, organic matter, starch and fibre was not significantly affected by method of cereal treatment. No problems of animal health arose throughout the three experiments.