Evidence of the need to improve welfare for hens in battery cages has come from any sources. Provision of a nest may be regarded as essential (eg. Kite 1985; Appleby and Hughes, 1990). There is general agreement that current spatial allowances are inadequate for welfare, while perches have been shown to improve foot condition and leg bone strength (Appleby and Hughes, 1990). These elements, in combination, may yield other benefits or drawbacks. Therefore, this study investigated the effects of spatial allowance, group size and the presence of a perch on comfort behaviour, nest use and nest soiling in caged hens.

In animal housing ammonia is an aerial pollutant resulting from the microbial conversion of nitrogenous materials excreted in faeces and urine. Ammonia is an irritant to cells lining the respiratory tract and an increased incidence of pneumonia in pigs and humans and atrophic rhinitis in pigs have been correlated with elevated ammonia levels. In a survey of 12 farms and 49 pig buildings concentration of ammonia was identified specifically as a causative agent in the aetiology of atrophic rhinitis (Robertson, Wilson and Smith 1990). Furthermore, high levels of ammonia can delay the onset of puberty in gilts perhaps as a result of the masking of boar odour (Malayer, Brandt, Green, Kelly, Sutton and Diekman 1988).

Regulations have been introduced (Control of Substances Hazardous to Health (COSHH)) limiting the exposure of humans to atmospheric ammonia to a mean level of 25 ppm over an 8h work shift and 35 ppm for 10 minute exposure. As part of a study on the effectiveness of a feed additive formulated to control atmospheric ammonia, levels of ammonia in pig housing were monitored.

If a housing condition results in impaired immune system function then vulnerability to disease is greater in that condition. Measures of immune system function can therefore be important indicators of welfare. Another indicator of welfare is the maximal adrenal cortex response to ACTH challenge. Ten third parturition sows kept in stalls, and 27 first parturition sows kept in an electronic sow feeder system have been studied. A direct measure of immune system function is to assess B-cell responses by measuring antibody production following antigen challenge. Sows in stalls were injected with tetanus toxoid, as commonly practised for protection against tetanus. The amount of antibody produced was negatively correlated with adrenal weight. The colostral antibody ELISA titre was 1/125,000 when the response to ACTH challenge was zero but was almost zero in animals which showed an increase in salivary Cortisol of 25 nmol l-1 after ACTH challenge i.e. antibody production was negatively correlated with adrenal response (r = -0.634, p = 0.028 (Fig. 1)).

When feed is offered ad libitum from hopper feeders, with water supply remote from the feeder, the feed conversion ratio with pelleted diets is improved by around 10% compared with non-pelleted diets (Patterson and Walker, 1989). This difference was reduced to around 6% when mono-place feeders with built-in water supply were used (Walker, 1990). The improved digestibility due to pelleting accounts for only 1% unit of these differences and the majority therefore appears to be due to feed wastage. A hopper feeder was developed by Baxter (1989) which minimised feed wastage of both pelleted and non-pelleted diets when assessed by short term collections of spilled feed. It was considered that a longer term growth trial would be a good indicator of the benefits of this feeder compared with other designs which had been used here in previous experiments.

The Slaughter of Animals (Humane conditions) Act 1990 prohibits killing animals within sight of another. There is a need to produce scientific evidence to show whether the sight of sticking (exsanguination) is stressful to animals that happen to observe this procedure. This has important consequences on the design of stunning and sticking areas in the abattoir. Sticking in a separate are can lead to a delay between stunning and sticking and increase the chance of animals regaining consciousness.

In this study experiments were carried out to determine whether sheep did responded in a way which could suggest they found the experience of witnessing sticking distressing.

After transport to the slaughter plant, pigs may be kept in lairage for up to 24h before being killed. This facilitates smooth, continuous operation of the slaughterline and, it is commonly believed, allows the animals to rest and so recover from the stress of transport. We have tested this latter belief by examining indices of stress in blood collected at slaughter from pigs kept in lairage for various times.

A total of 320 LW x (LW x LR) pigs (89 kg) of both sexes were used. They were killed in ten batches. Prior to slaughter they were transported for 2h (80 km) at a stocking density of 0.52 m2 per 100 kg live weight. On arrival at the IFR-Bristol slaughterhouse the pigs were killed either as soon as practicable after unloading off the transporter (Oh lairage), after 3h in lairage or after holding in lairage overnight (21h). Half the pigs held overnight were fed in lairage (in the late afternoon), half were not. At slaughter therefore, pigs in the four different lairage treatment groups had been subjected to food withdrawal periods of 3, 6, 16 and 24h.

Many stressful procedures have been shown to cause elevation of plasma ß-endorphin (ß-EP) and Cortisol in sheep. These include shearing and electroimmobilization (Jephcot, McMillen, Rushen, Hargreaves and Thorburn, 1986), routine surgical procedures (Shut, Fell, Connell, Bell, Wallace and Smith, 1987), hypoglycaemic stress (Owen, Smith, Green and Falconer, 1984) and procedures such as handling, transport and slaughter (Fordham, Lincoln, Ssewannyana and Rodway, 1989) as well as change of environment (Fordham, Al-Gahtani, Durotoye and Rodway, 1991). The aim of the present study was to examine the effect of a very reproducible and easily applied stress, namely Isolation from other animals, on plasma ß-EP and Cortisol and also to study the effect of suppression of hypothalamo-pitultary axis with dexaniethazone during isolation. Six ovarlectomlzed ewes (48±3kg) were housed in groups of two in separate pens without visual contact between pens. In each experiment one ewe of each pair was removed from the pen. The remaining ewe was therefore isolated both physically and visually from its partner and was blood sampled every 10 min via a jugular catheter.

Ovine enzootic abortion (EAE) is of major concern to sheep producers. Various schemes are currently in existence for its eradication, all based on an initial two year monitoring period during which a predetermined number of ewes in each participating flock are blood tested at strategic points in the annual cycle of production for determination of EAE antibody titres. The risk of introducing EAE is primarily dependent on flock replacement policy. Using home-bred replacement ewe lambs and wintering them on the farm of origin eliminates the risk of introducing EAE.

The objective of the present study was to evaluate various home wintering systems in terms of their cost effectiveness and compatibility with other farm enterprises.

There is increasing interest in the development of later lambing systems for crossbred ewes which more closely match ewe nutritional requirements with grass growth (Stone, 1988). Lambing a proportion of the flock during summer potentially ensures a better continuity of lamb supply but the superior growth rate of summer born lambs dictates that finishing is not delayed to as great an extent as would be predicted from lambing date. The objective of the present study was to determine whether it is possible to alter lamb growth by controlling herbage availability without detriment to ewe body condition.

The liveweight change of sixty four Mule ewes and their summer (24th May) born twin lambs was evaluated when grazing unfertilised clover rich swards maintained at a sward surface height (SSH) of 4-6cm (Treatment A) or rising from 4-6 to 6-8cm (Treatment B). Grazing treatments were duplicated with equal numbers of animals per treatment and commenced on 19/6/90 (day 0). Throughout the grazing period SSH was monitored twice weekly using a sward stick and was maintained within the target ranges by movable electric fencing. Samples for determination of herbage mass and botanical composition were obtained at monthly intervals. Lambs were weighed fortnightly, ewes were weighed and condition scored monthly until weaning on 28/8/90 (day 70).

In a rotational grazing system for dairy cows, to achieve maximum yield/cow, optimum post grazing stubble height of between 8-10 cm is recommended. At this mean height, however, selective patchy grazing and excessive stem production occurs, particularly around dung patches. Sward deterioration gets progressively worse as the grazing season progresses, resulting in a decline in pasture utilisation and output. An alternative to topping to improve sward structure is a leader-follower system with sheep, as tested In Ireland (O'Riordan, 1989). A pilot investigation was carried out in 1989 and a more detailed evaluation of the technique was made in 1990. Results for 1990 are reported in this paper.

A high yielding herd of 114 Holstein/Friesians (herd average 7200 l), in a genetic selection programme at the University of Edinburgh's Langhill Farm, were turned out on 3 May 1990. The cows rotationally grazed 2-3 ha paddocks for 3-4 days. Speed of rotation was determined by herbage availability and daily milk production, every effort being made to ensure that herbage intake to the dairy cows was never limiting.

Supplements of readly digestible cellulose and hemicellulose enhance fibre degradation by promoting the growth of eellulolytic microbes in the rumen. In the current study supplements of ammonia treated straw were fed to a basal diet of untreated straw and intake, fibre digestion and rumen fermentation assessed.

Four mature castrated male sheep weighing 50.5 to 69.6kg and fitted with permanent rumen cannulae were used. The experiment had a 4 x 4 latin square design such that the sheep were fed four diets and measurements taken oyer four periods. Each period consisted of 10 days adaptation and measurements taken for a further 8 days.

The diets comprised untreated straw (control) ammonia treated straw (AS) or untreated straw together with 200g AS or 400g AS (200AS and 400AS respectively). Straw was treated with 3.5% ammonia (w/w). Untreated straw was supplemented with 1% urea (w/w). In addition both straws were supplemented with minerals and vitamins. Straw was chopped (4cm screen) prior to feeding. For diets 200AS and 400AS the treated and untreated stsaws were given in seperate troughs.

The removal of ciliate protozoa, or defaunation, results in the establishment of a new ecosystem in the rumen, consisting only of bacteria and fungi. Although extensive research has been done on ciliate-free ruminants, the role of protozoa in the rumen still provokes considerable debate. The diversity of experimental design, such as animal species, defaunation method, and diet could account for many of the differences observed between defaunation studies. Also it is important to examine the stability of the ciliate-free ecosystem. The aim of this study was to investigate changes in rumen fermentation of ciliate-free sheep over a period of one year.

Eight male castrated sheep, weighing 60-70 kg, received twice daily 700 g of a diet of hay, barley, molasses, fish meal and vitamins/minerals (500, 299.5, 100, 91 and 9.5 g/kg DM respectively). Four sheep were defaunated by the rumen washing technique (Jouany and Senaud, 1979) and kept in isolated pens while the other four were left faunated with a mixed type A ciliate protozoa population. Rumen samples were withdrawn via the rumen cannula and blood samples were taken from the jugular vein -1, 0, 1, 2, 4 and 6 h after feeding. There were three sampling periods: one month, six months and one year after defaunation.

A wide range of compounds has been described which have the potential to improve animal production by manipulating the rumen fermentation. Prominent among these rumen modifiers are the ionophores. Ionophores, such as monensin and tetronasin, improve feed efficiency, partly by increasing the flow of amino-N from the rumen and partly by stimulating the production of propionate in the rumen with an associated reduction in the production of methane (Russell and Strobel, 1988). Recently there has been increasing interest in the use of yeast culture (YC) and other fungal preparation to modify the rumen fermentation. These products have been shown to increase bacterial numbers within the rumen with an associated increase in the breakdown of fibre and supply of microbial protein (Williams and Newbold, 1990). YC has also been reported to increase the production of propionate in the rumen. Little appears to be known about the effect a combination YC and an ionophore would have on the rumen fermentation. This study describes the effects of the ionophores monensin and tetronasin on the fermentation of hay by rumen fluid from sheep fed a basal diet with or without YC.

The production of colostrum by prolific ewes is of particular importance because of the increased demand of larger litters. Robinson (1985) has shown that there is a sharp increase in the ewe's net protein requirement for udder growth and colostrum production in the last 2 weeks pre-partum.

The trial was designed to investigate the effect of level of protein in the diet during the last weeks of pregnancy on the quantity and quality of colostrum produced by prolific ewes.

Forty-four Cambridge ewes aged 2 to 7 years and scanned as carrying two to four lambs were used. Ewes were housed and sheared approximately 2 months pre-partum and fed a complete diet at a restricted level and hay ad libitum until the commencement of the feeding trial at 2 weeks pre-partum. The ewes were then individually penned until 5 days post partum. During this period the ewes were fed ad libitum one of the two complete diets detailed in Table 1 together with hay ad libitum.

Intakes of well-fermented silages by store lambs can be disappointing, with liveweight gains well below the 100 to 125 g/d required to fatten lambs over the winter. To achieve high levels of gain it has been necessary to supplement grass silages. Barley, as an energy supplement, has increased the intake of dry matter but often the intake of silage dry matter is decreased. Protein supplements, on the other hand, have been shown to increase silage DM intake. The objectives of this study were to compare the effects on intake and performance of store lambs of two supplements of differing protein content when offered as the sole constituent of the diet or with one of two silages at two levels of supplementation.

After a 24 hour wilt, perennial ryegrass (Lolium perenne) was ensiled: half of the material was untreated and half was treated with an additive which contained lactic acid bacteria (supplying 106 cfu/g), Lactobacillus plantarum and Pediococcus pentosaceus and enzymes derived from Trichoderma reesei.

The proposed reduction in lamb variable premium payments could well lead to fewer lambs being sold as stores, with more being finished on the farms of origin. On upland farms such lambs are likely to be finished indoors to reduce competition at grass with ewes being flushed. Many farms now have accommodation for housing ewes for 3 months prior to lambing, and such housing can easily be used to finish lambs prior to housing the ewes. On grassland farms finishing is likely to be based on silage which, represents a relatively cheap, home-grown feed. However, lamb performance on silage alone is likely to be inadequate and unpredictable, so that in most cases supplementary feeding will be requited. Type of supplement is likely to have important influences on both physical and financial performance.

The 144 Scottish Blackface wether lambs used for this trial were selected from a group of 455 lambs bought in the open market on 29 September 1989. The lambs were run at grass until selection for the trial on 27 November when the 144 selected lambs were drawn out and introduced to compound feed.

The selection of lactic acid bacteria for use as silage additives is normally based upon their ability to dominate the silage fermentation and not upon benefits in animal performance. The object of this study was to investigate whether two lactic acid bacteria selected for fermentation characteristics would support the same animal performance as an established silage inoculant.

On 5 June 1989, first cut, predominantly perennial ryegrass (Lolium perenne) was ensiled direct with no wilting in plastolene silos of 2 tonne capacity. The herbage was harvested with a precision chop forage harvester and the following additive treatments were applied: None, control (C); Formic acid (Add-F, BP Nutrition, 850g/kg; 3 litres/tonne), (F); inoculant E. (Ecosyl, ICI Pic, 106Lactobacillus plantarum /g): inoculant A, (Pediococcus sp, 10 /g); inoculant B (L. plantarum 106 /g). The silages were fed to 6 wether sheep (Suffolk x Halfbred), initial live-weight, 40.1 kg (s.d. 2.22kg). Because the silages were unstable aerobically and restricted quantities of each silage were available, all sheep were fed the silages in the same (random) order.

Early weaned lambs have been successfully reared to slaughter on ad libitum concentrate diets for many years, mainly in systems involving out of season lamb production where high market prices offset the comparatively high feed costs. In these systems maximum growth rates are required to enable lambs to reach acceptable slaughter weights before market prices fall.

Feeding systems may be based on whole cereals supplemented with small, high protein pellets, a technique developed from Rowett studies (Orskov et al, 1974) or home made blends of processed cereals and by-products or proprietary concentrates. Component selection Is a common problem with diets based on whole grains and although this can largely be overcome by correct feeder design this incurs considerable expense. Diet selection can be reduced by processing grain (eg on farm rolling) or by pelleting. Cereal processing and pelleting however can have deleterious effects on rumen function as described by Orskov (1973), the effects being attributed to both inadequate saliva production and reduced rumen surface stimulation by roughage.

Environmental pressures on the agricultural industry to reduce the use of nitrogenous fertilizer, coupled with improvements in varieties now available, have heightened interest in the use of white clover on livestock farms in the United Kingdom. Furthermore white clover is nutritionally superior to ryegrass, particularly in its protein content. Store lambs require a high quality feed so that they grow well and achieve the desired amount of carcass finish. In this investigation the performance and subsequent carcass characteristics of store lambs finished on white clover or perennial ryegrass swards are compared.

During the autumn of 1989, eighty four Texel x Welsh Mule wether lambs were divided into 4 balanced groups. Each group was penned into 0.65 ha paddocks of either white clover (C) or perennial ryegrass (PRG) swards to give two groups of twenty four lambs per sward type.

The clover sward (3 ha field) was sown on 3 August 1983 with 6.85 kg/ha of an equal mixture by weight of Nesta (large leafed variety) and Menna (intermediate variety). Three silage cuts had been taken during the 1989 season totalling 7.2 tonnes DM/ha, the third cut being taken on 19 September.

Reduction of the financial support by the EC to sheep farmers has highlighted the need for lamb fattening diets which can adjust the rate of lamb growth, depending on market needs. A trial was run at BOCM SILCOCK Development Unit, Barhill using 144 Texel and Suffolk x Mule lambs, with a mean start weight of 18.6 ± 0.50 kg (mean ± SE). Lambs were divided into 24 pens and allocated one of four compound diets (Diets A, B, C or D). The diets were designed to be isoenergetic with an estimated energy of 11.4 MJ ME/kg DM and contained 138, 172, 206 and 250 g crude protein/kg DM. Protein levels were increased by increasing soya bean meal inclusion from 0 to 25% and reducing barley and wheat levels.

Formulations and actual analysis are shown in Table 1. Lambs were bedded on barley straw refreshed daily, with compound diets and water available ad-lib.