During the distillation of wheat to produce whisky, two residual products are formed. These are the spent grains and a thick syrup resulting from evaporation of the liquor remaining after the whisky has been distilled off. These by-products may be combined to form undried dark grains (UDG) or further dried and pelleted to form wheat distillers dark grains (WDDG). UDG and WDDG were evaluated as feeds for ruminant livestock.

WDDG had the appearance of a typical concentrate pellet, dark brown in colour with a molasses like malty odour. UDG was lighter brown in colour but formed a dark brown surface crust on exposure to air. The bulk of the material had a granular putty-like texture and a smell akin to that of WDDG. Compositions of the two by-products and that of distillers dark grains derived from barley fernentation alone are given in Table 1.

To date, practical methods of improving the digestibility of straw are largely confined to treatment with alkalis (Sundstol and Owen, 1984). Though effective, these chemicals can be hazardous for on-farm use and are potential pollutants. Biological methods of upgrading straw using fungi or enzymes (Zadrazil, 1984) would be less hazardous and more acceptable if practical and economic techniques could be developed. The present experiment examined the potential of ligninase enzyme produced from the fungus Phanerochaete ohrysosporium for upgrading straws. The aim was to define treatment conditions required. Treatment with sodium hydroxide was included as a positive control. Treatment effects were assessed by measuring changes in digestibility in vitro and chemical composition.

Seventy two treatments were compared. 10 g samples of milled (1.0 mm) straw were immersed (ambient temperature 15°C) in 100 ml buffered (pH 3.5) solution, with one of four levels of ligninase (zero; 0.1 unit/10 g straw; 1.0 unit; 10 units; one unit of enzyme oxidises 1 μmol veratryl alcohol to veratraldehyde per minute, at pH 2.75), with or without hydrogen peroxide (ligninase depends on H2O2 for its oxidative reaction), veratryl alcohol (used to induce the ligninase production and activity), or both of them.

Many different chemicals have been used for upgrading poor quality crop residues (sodium hydroxide, Jackson, 1977: ammonia, Sundstøl et al., 1988: Magadi soda, Nangole et al., 1983: organic waste ash, Adebowale, 1985: alkaline hydrogen peroxide, Gould, 1985; Lewis et al., 1987). Upgrading of crop residues by chemical treatment is the result of disruption of the cell wall structure to a point where the bacterial and fungal enzymes of the rumen can hydrolyse component of polysaccharides previously not accessible. One important constituent of cell walls acting as a barrier to the enzymes is lignin. Alkaline hydrogen peroxide is known to degrade lignin via a sequence of free radical reactions which are optimal at a pH 11.5 (Gould and Freer, 1981; Gould, 1985). An associated problem of upgrading crop residues is the low nitrogen content of such feeds. To alleviate this deficiency both ammonia and urea are commonly used to raise nitrogen.levels. In this study, the effect of sodium hydroxide alone and sodium hydroxide plus hydrogen peroxide are compared. The effect of pretreating straw with hydrogen peroxide and subsequent treatment with anhydrous ammonia was also investigated.

Expt. 1. Solutions of hydrogen peroxide were adjusted to pH 11.5 by addition of NaOH and added to straw to give 1 g H2O2/100 g straw. In order to achieve this pH 0.5 g of NaOH was used/g H202. In the second treatment therefore the NaOH was added without the H2O2- For treatment 3 10 g H2O2 was added per kg of straw and in order to achieve a pH of 11.5 5.5 g NaOH had to be used. Consequently in treatment 4 5-5 g NaOH was added without the H2O2.

A study of the intake potential of a range of well-preserved silages offered to lambs over several years showed that, of the many parameters considered, those with the greatest positive effect on DM intake were sugars in the grass as ensiled, residual sugars and protein nitrogen in the silage, with ethanol concentration in the silage having a negative effect (Henderson, Anderson and Phillips, 1984). In the experiments reported here ADD-F (85 per cent formic acid) from BP Chemicals International was applied to ryegrass at a rate sufficient to conserve much of the sugar (WSC) in the silage by inhibiting the growth of the micro-organisms on the grass. The initial lowering of the pH should also inhibit the activity of the plant enzymes, conserve protein nitrogen (PN) in the silage and prevent extensive deamination.

In 1986 first-cut perennial ryegrass, and in 1987 Italian/perennial ryegrass, was ensiled direct-cut, untreated or treated with 5 1 ADD-F/t grass in 100t capacity clamp silos. The grass was cut with a mower and lifted with a precision-chop forage harvester. The acid was pumped onto the grass through a dribble bar sited over the pick-up drum.

Operation of whisky distilling plants throughout the year produces considerable quantities of by-products malt distillers grains (draff) during the summer months. Draff is traditionally used as a ruminant feedstuff with the greatest demand being in winter. Competitive prices during summer make draff a very attractive buy and summer purchase, with subsequent storage on the farm for winter feeding is now a widely accepted, practice. However,, there is little information about the consequencies of long term draff storage or a detailed evaluation of different ensilage methods. This investigation examined the effects of three different storage methods on dry matter losses in the silo, and evaluated the recovered feedstuff using young steers.

Storage methods - Each storage method was examined in duplicated sleeper walled silos, each containing approximately 6 tonnes of draff. The silos were roofed and had individual effluent tanks. For method 1 draff was tipped into the pits and a top sheet was held in place by an incomplete surface covering of sandbags.

The feeding of whole barley grain to breeding ewes is widely recommended yet it is recognised that a proportion of the grain fed in this form is usually passed intact in the faeces. It is claimed that whole grain improves the rumen fermentation process because it is broken down more slowly than milled grain and this, together with the saving in the cost of processing, means that a loss of up to 0.10 of grain intake in the faeces is considered acceptable. However there have been claims that on silage-based diets the proportion of grain passing intact in the faeces may be higher than 0.10 (Vipond, Hunter and King, 1985). In a preliminary study at this Institute with ewes on silage based diets in late pregnancy 0.18 of grain consumed was recovered intact in the faeces.

In 1988 45 ewes in late pregnancy were fitted with faecal collection bags as described by Vipond, Hunter and King (1985) during two 4-day periods 5 and 3 weeks before lambing and during a further 4-day period 3 weeks after lambing. In the two pre-lambing collection periods ewes were allocated at random from uniform groups to one of 5 forages (4 silages and 1 hay). Three of the silages were made from primary growths of a ryegrass pasture, one cut on 25 May with a single-chop harvester (SI) and two cut on 8 June, one with a single-chop (S2) and one with a precision-chop (S3) harvester. The fourth silage was a second cut, harvested on 29 June with a precision-chop harvester (S4). Hay was of medium quality and was bought in. All forages were offered. ad libitum so that intake was 0.9 of forage offered. Ewes were offered 250 and 600 g/d whole barley 5 and 3 weeks before lambing respectively and 800 g/d 3 weeks after lambing. In the faecal collection after lambing all ewes received the same roughage (silage S4) and values for the proportion of intact grain in the faeces at this stage were used to adjust values 5 and 3 weeks pre-lambing by covariance.

Insufficient information is available on Whether significant differences exist between digestive efficiency of pregnant cattle and sheep and that of the corresponding male castrates. The latter animals are invariably used to obtain digestibility values for foods or diets Which are applied to other ruminant animals including pregnant females. Three experiments have been undertaken in Which the digestibility of two diets fed at two levels Was compared in eWes and Wethers (two experiments) and steers and heifers (one experiment). For each species the females Were in the last trimester of pregnancy.

The diets were similar to those used in recent Work on pregnant cows and designed to contain a similar amount of RDP, but different amounts of UDP i.e. 0.17 (low) and 0.29 (high) of total crude protein. The low UDP diet contained (on dry matter basis) barley straw (0.39), barley grain (0.40), molassed meal (0.Z0) and urea (0.01). The high UDP diet contained (on DM basis) barley straw (0.38), barley grain (0.18), malt distillers dark grains (0.11) and special propietary cubes (0.33). The levels of feeding were 1.0 and 1.5 x maintenance.

Probiotics (microbial preparations and their growth media) are of increasing interest as feed additives for both ruminant and non-ruminant livestock. Amaferm is a fermentation extract prepared from cultures of the fungus Aspergillus oryzae which, when included in the diet of dairy cows, increases the yield of milk and buttermilk (Harris et al. , 1983). These improvements have been associated with changes in rumen fermentation (Weidmeier et al., 1987). The present study describes the use of the rumen simulation technique Rusitec (Czerkawski and Breckenridge, 1977) to investigate the effects of increasing doses of Amaferm on the stoichiometry of rumen fermentation in vitro.

Amaferm was added at 0, 25 and 250 mg/d to duplicate Rusitec vessels and at 1 g/d to a single vessel, receiving 10 g/d of a mixed diet of hay, barley, molasses, fishmeal and vitamins/minerals (500, 299-5, 100, 91 and 9.5 g/kg DM respectively). Vessels were initially inoculated from animals receiving the same diet. Artificial saliva was continuously infused into the vessels (total volume 850 ml, dilution rate 0.88/d) and feed bags were changed daily such that each bag was incubated for 48 h. Samples were taken at the time of feeding after 15 d adaptation to Amaferm.

Amaferm had no influence on total VFA concentrations but there was a shift towards an increased proportion of butyrate as the level of addition increased. Ammonia production was also stimulated by the addition of Amaferm, with the concentration in the vessel receiving 1 g/d being almost twice that found in the control vessels. There was no effect on dry matter disappearance after 48 h. The concentration of methane in the gas collected from the head space of the vessels was decreased by Amaferm, with the maximum decrease (17%) being seen at the level of 250 mg/d.

The use of brewery by-products which contain varying quantities of live and dead yeast cells as nitrogen supplements in diets for ruminants is well documented.

There have been several recent reports of micro-organisms, previously considered as being totally aerobic, multiplying and exhibiting growth in the rumen and in rumen simulators and conferring beneficial effects on cellulolysis and growth or productive capacity of the animal. Dawson (1987) reported that certain strains of yeast (Saccharomyces cerivisae) multiplied when introduced into the rumen. Although at some point extensive lysis occurs with extrusion of the cell contents (Bruning and Yokoyama, 1988). The present experiment was carried out to assess the effects of including yeast culture (YS) (Saccharomyces cerevisae, plus growth medium: 5x106 organisms/g) in diets for ruminants. The responses in terms of effects on rumen metabolism were monitored in three cannulated steers.

The aim of the experiment was to determine the effects on the rumen metabolism and the degradability of a forage using the nylon bag technique (Ørskov and McDonald, 1970) when yeast culture was added to two contrasting diets and given to young steers. The diets were either a high forage diet of hay or a mixture of forage plus concentrate given in such a manner as to induce a negative associative effect.

Tetronasin (ICI 139603) is an ionophore which improves feed efficiency in ruminants (Bartle et al., 1988). Its nutritional effects are at least partly derived from its influence on nitrogen and energy metabolism in the rumen. The mode of action of tetronasin is therefore similar to monensin and although it is more potent than monensin, it has a similar spectrum of antimicrobial activity (Newbold et al., 1988). The aim of the present study was to examine the effects of the inclusion of tetronasin in the diet on the ability of the resultant microbial population in the rumen to degrade casein, peptides and amino acids.

Thirty castrate Friesian & Hereford crosses were fed a diet of barley, ammonia treated straw, soya bean meal, molasses and mineral/vitamin mix (62.5, 20, 12.5, 2.5 and 2.5% of dry matter respectively) ad lib, with the animals being split into three treatment groups, each of ten animals, receiving 0, 6, and 10 mg tetronasin/kg of total diet. Rumen samples were taken by stomach tube from all animals 42 and 84 d after the start of the trial. Samples were strained through two layers of muslin before use.

The feeding of rapidly fermentable, high energy, diets to young calves stimulates a rapid development of microbial fermentation. High concentrate diets may not, however, stimulate a corresponding development of salivary flow (Kay, 1966). A number of factors affect the buffering system of ruminal contents, besides saliva, such as the concentration of the end products of fermentation and the rate at which these products are absorbed through the rumen epithelium (Turner and Hodgetts, 1955). Counotte, van Klooster, van der Kuilen and Prins (1979) presented the analysis of the buffer system in the rumen using the first derivative of the titration curve. The results showed that bicarbonate and VFA are the main chemical components of the buffer system in the rumen fluid of adult dairy cattle. The ability to buffer against potentially large deterimental fluctuations, ie rumen pH, may improve rumen stability and be benefical to stimulate solid food intake in the early weaned calf. The present experiment describes a system for analysing the buffer system in the developing rumen of the young calf.

There is evidence that in growing lambs, net nitrogen requirements are affected by breed, sex, weight and level of feeding but little is known about the effect of dietary concentration. The purpose of the present experiment was to examine the effect of feeding straw diluted diets on nitrogen retention in Rasa Aragonesa lambs from weaning to slaughter.

Eight male lambs, 40-45 days old and 12.3 ± 0.47 kg live weight, were allocated to one of two pelleted diets containing 6 (C) or 23 (D) percent of barley straw and barley, soya bean meal and fish meal to give a crude protein content of 193 (C) and 186 (D) g/ kg dry matter. Both diets were fed ad libitum and nitrogen balances were carried out at 14, 21 and 29 kg live weight. For diet C at the last weight only the balance of two lambs was recorded.

The results are shown in table 1. Although the digestible organic matter (DOM) content was higher (P ≤ 0.005) for diet C (690 g/kg DM) than for diet D (606 g/kg DM), DOM intake was not significantly affected by dietary dilution. Nitrogen retention was higher at the lowest live weight for both diets and decreased at each live weight with dietary dilution (P ≤ 0.005). No significant period x diet interaction was found.