Alfalfa is recognized as more difficult to ensile than maize. Typically, multiple alfalfa cuttings are harvested at various stages of maturity, and numerous maize hybrids that vary in their nutritive value are used for silage production in North America. The objective of these studies was to determine the effects of commercial bacterial inoculant and water soluble carbohydrate (WSC) additions on the microbial succession and silage fermentation process of two cuttings of alfalfa and three whole-plant maize hybrids.

In 1989, second and fourth cuttings of alfalfa were mowed and swathed at the late-bud, 10% bloom, and 50% bloom stages of maturity within each cutting and wilted in the windrow for 5 to 6 hours prior to precision chopping. Three maize hybrids (Pioneer 3377, 3379, and 3389) were grown under irrigation in 1989 and harvested at the two-third milk line of kernel maturity.

Extent of fermentation in the silo can, through effects on silage composition, have important consequences for milk yield and composition. However, a poor understanding of the relationships between the chemical composition and digestion characteristics of silage, and of the implications for nutrient supply, makes it difficult to predict performance and to formulate concentrates to complement silages of different types. The 2 experiments presented here were conducted to determine rumen fermentation patterns for a range of silages, representative of restricted or enhanced fermentation in the silo, when supplemented with concentrates containing a high proportion of either starch or digestible fibre.

In each experiment 8 rumen-fistulated sheep were used to compare 8 silages, each given with 2 concentrates. Each experiment was conducted as four 4x4 Latin squares, with 2 silages given with each concentrate in a single square. Silages 1-12 were prepared from perennial ryegrass swards, harvested within 2-5h of cutting, precision-chopped to a length of approximately 20 mm, and ensiled in bunker silos of 60- or 300-tonne capacity.

One of the main problem of preserving forages by ensiling is the high proportion of non-protein N of the silage as a consequence of the proteolitic action of plant enzymes and the consequent poor utilization of N by the ruminant.

Several procedures have been developed with the aim of reduce this protein breakdown but these methods could reduce the ammount of N available for tie rumen microbes and the N digestibility in the post-runinal tract. This study was set up to determine the rumen degradation characteristics of silages treated wit different additives.

Three silages were lade from the 3rd cut of a grass-legune mixture sward in 1 t capacity silos. The herbages were treated with either no additive (C), formic acid (4 1 of a solution of 85% foric acid/t of grass) (F) or fonaldehyde (4.9 g fonaldehyde/100 g grass CP) (FA).

A major difficulty in producing detailed rations for ruminants, where grass silage is offered ad libitum lies in the accurate prediction of silage intake. It is well documented that ammonia and increased levels of acetic, butyric, caproic and valeric acids in grass silages have negative effects on intake, whilst increased organic matter digestibility has a positive effect. (Gill, Book and Thiago, 1988). A laboratory assessment of silage fermentation characteristics is usually determined from freshly cored samples. Depending on the stability of the silage, and the feeding method, results of such assessments may not be indicative of the silage on offer to stock.

A laboratory method of determining the aerobic stability of silage has been developed by ADAS at Slough Laboratories between 1988 and 1990, (Brooks 1990).

Silage has substituted hay as the major conserved herbage in Galicia due to the well-known nutritional benefits of the former. However, the heavy spring rainfall has caused widespread problems in silage conservation quality. Consequently, silage additives are used increasingly and the benefits of formic acid under difficult ensiling conditions have been recognised. Recently, biological fermentation enhancers have become available but there is little knowledge of their usefulness under local conditions. Moreover, since silage is not generally used in sheep production systems in Galicia, an experiment was designed with the twin objective of determining the effectiveness of two silage additives whilst testing the suitability of silage for the finishing of spring-born lambs during the dry summer.

Using a double-chop silage harvester with additive applicator, three 15-tonne clamp silages were made from a predominantly ryegrass permanent pasture on 25 April 1991 during persistent rainfall (c.6.5 litres/m2/day) . Silage C (control) had no additive; silage F received 3.2 litres of 85% formic acid/tonne fresh herbage (FH); and silage B had l0g Sil-Add/t FH (Alltech Inc.). Sil-Add consists of lactic acid producing bacteria, an enzyme complex and an anticlostridial factor.

Increasing the number of lambs reared when breeding from ewe lambs in a lowland situation usually leads to improved profitability. The effect of pre-mating shearing on lambing rate, lamb birthweights and their subsequent growth rates was evaluated.

Two hundred and twenty (Blue-faced Leicester x Swaledale) ewe lambs were purchased in early mid-September over a period of 3 years (1988-90). They were offered 225 g of whole barley per head daily until housing in early January. Half of each intake was shorn approximately 7 days after arrival and on average 31 days prior to joining with entire Suffolk rams. Ewe lambs from both treatments were run together as one group and remained with the rams for three cycles.

Feeding straw as the only roughage to housed ewes during the winter is gaining in popularity. This practice requires new grazing techniques because silage aftermaths might not be available in the summer to reduce stocking rates as grazing demands increase. It has been shown that set stocking ewes at either 22 or 30 ewes/ha and feeding a creep feed to the lambs ensured that all lambs were sold by August and gross margins/ha were increased (Brown, 1986). However, at these high stocking rates coccidiosis was a problem.

222 Mule ewes with their Suffolk or Polled Dorset cross lambs were divided into 6 similar groups. Each group were set stocked in a 1.4 ha plot so that 31 ewes with 57 lambs grazed at 22 ewes/ha, and 43 ewes with 79 lambs grazed at 30 ewes/ha.

In the final 2 weeks of pregnancy there is a large increase in the protein requirement of the ewe for udder growth and colostrum production (Robinson, 1985). Ewe dry matter (DM) intakes fall during late pregnancy (Forbes, 1970) so meeting the theoretical requirements at this stage can be difficult.

The trial was designed to compare the effect of providing the required protein on a flat-rate or a ‘step-up’ feeding system on lamb and colostrum production.

Sixty-two Cambridge ewes aged 1 to 9 years and scanned as carrying 2 to 6 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 trial at 4 weeks pre-partum.

Sustainable clover dominant swards have been developed for upland UK sheep grazing conditions by sowing a mixture of tetraploid perennial ryegrass cv Condesa and small leaved clover cv Aberystwyth S184. These pastures have produced equal output to Condesa only swards given 150-160 kg N/ha/year. Lamb liveweight gain from April to August was increased by 50 g/day on the grass/clover vs grass swards. A comparison of the suitability of these grass/clover and N-fertilised grass only swards for silage was undertaken in order to assess silage yield potential and silage feeding value. The enhanced animal performance of lambs on clover has been partly attributed to the higher levels of dietary amino acid clover has been observed to provide. In order to quantify this effect sufficient supplementary fishmeal (60 g/day) to fully meet tissue N needs was fed to lambs on the grass/clover and grass silages and responses in lamb performance compared.

In hill sheep systems, a major concern for health and welfare is for lambs grazing improved land at higher stocking rates and succumbing to parasitic gastro-enteritis. With only a small amount of improved land available, there is little or no scope for ‘clean grazing’ systems as access to this better land is crucial on an annual basis to achieve better performance from the flock. Access at lambing and at ewe mating is of particular value. There may however be some scope for reduced parasitic challenge to lambs during the summer grazing period because of the differential in stocking densities between the hill and the improved grazings.

Lambs are known to change their feed intake in relation to environmental temperature (Blaxter, 1962). However, their ability to select a non-limiting diet, when free-choice fed, has only been investigated in a thermoneutral environment (Cropper, 1987). The aim of this experiment was to test the idea that, at low and high ambient temperature, (a) feed intake would increase in the cold and decrease in the hot, relative to a thermoneutral control, and that (b) the protein content of the diet selected would be lower and higher respectively.

Future human population increases will require more land being devoted to cereal production. This will demand that ruminants be increasingly reliant on crop by-products for feed. The greater integration of crop and animal production will require more reliance on stall feeding systems. There is little published information on stall feeding systems for sheep and goats. Furthermore there is little information on the design of stall feeders for these animals. This paper reports an experiment designed to measure the reach capacity of sheep and goats in order to provide base line data which will be required when designing feeders for them.

There is much current interest, with little supportative evidence, in the use of specialized mineral supplements for ewes at mating. Seaweed meal is a mineral source which is approved under Organic Production Standards. The objective of the present trial was to determine the effect of seaweed meal supplementation on the mineral status and fertility of summer (May-June) lambing ewes managed on an organic system.

Sheep housed after grazing and offered straw as a feed show reluctance to eat for several days. Evidence exists to indicate that eating habits can be manipulated through a learning process, especially if manipulation occurs pre-weaning. Australian research by Arnold and Mailer (1977) with unpalatable pastures, and Green, Elwin, Mottershead, Keogh and Lynch (1984) with whole cereal grain, showed that sheep exposed to these feeds early in life were more willing to accept the feeds later in life than others not exposed.

The present experiment investigated whether this observation was applicable to lambs exposed to a poor quality roughage like barley straw.

Clean grazing systems for sheep have been developed to minimize helminth challenge to susceptible lambs. Provision of clean grazing relies upon effective control of overwintering helminth infection on pasture and particularly in the post parturient ewe. During early lactation ewes immuno-competence is reduced resulting in the excretion of helminth eggs for approximately six weeks post lambing (Thomas, 1973). Control of this source of infection may be achieved by strategic anthelmintic administration while overwintering pasture infection may be avoided by use of pasture which has not carried sheep in the previous year.

Prophylactic anthelmintic administration is unacceptable under an organic management system and consequently alternative strategies must be sought to eliminate the ewe as a source of infection. The objective of the present study was to evaluate strategic transfer of ewes and lambs to a silage aftermath as a means of minimizing helminth challenge to susceptible lambs.

The assessment of herbage intake using the n-alkane technique requires estimates of the n-alkane concentrations in the diet. The objective of the present study was a) to assess the magnitude of sampling variation in n-alkane concentrations among herbage samples taken from individual oesophageal fistulated wethers, b) compare n-alkane concentrations determined from oesophageal extrusa, hand plucked, and mechanically clipped herbage samples and c) assess the effect of errors in the estimates of herbage n-alkane concentrations on the accuracy of intake estimates.

Under Australasian conditions vasectomised (teaser) rams are widely and successfully used for the induction and synchronisation of oestrus in ewes. However under UK conditions success has been limited possibly as a consequence of the more marked seasonality exhibited by UK sheep stocks. The transitional phase of ewes in July at latitude 57°N may require a greater degree of stimulation than can be achieved using teaser rams at 2-4% of the flock. The rams may also be in sub-optimal breeding status resulting in lowering of their libido and hence stimulatory effect on the ewes.

Cereals are traditionally used as a supplement for store lambs grazing swedes in situ. However Dingwall, Vipond, Brown and Hunter (1989) demonstrated superior lamb growth and slaughter characteristics when soya was used as an alternative supplement to barley. It is thought that under the unusual conditions of high rumen turnover rate and rapid fermentation associated with root feeding a rumen degradable protein to metabolizable energy ratio (RDP:ME) of 10 to 12:1 may be more appropriate than the 7.8:1 normally found in ruminant diets.

There may be practical problems associated with feeding soya to lambs outdoors and specialized soya based pellets have been developed. Both soya and soya pellets are relatively expensive and farmers may seek to enhance store lamb growth using cheaper alternative protein sources. The objective of the study reported here was to evaluate distillers draff and forage rape as supplements for store lambs grazing swedes in situ.

In a market where high levels of fat on lamb carcases are not favoured, the supposition that a lamb, given adequate feeding, will grow protein preferentially to gaining lipid, holds interest. However, this idea runs counter to the evidence that body composition is not manipulable in sheep. Therefore, an experiment was undertaken to implement extreme treatments of protein and energy supply to determine to what extent the contrasting views on body composition changes in growing lambs are justified.

Seventy-two Coopworth ram lambs (mean liveweight, (LW) 30.4, s.d. 1.1 kg) were given one of the three feeds of different digestible crude protein (DCP) content at one of three allowances (ad libitum (AL), 1.2 (H) or 0.8 (L) kg/day). The feeds (H, M and L) were formulated as shown in Table 1. Feed M was a mixture of 0.55 Feed H and 0.45 Feed M. The proximate composition, measured DCP and estimated metabolisable energy (ME) content of the feeds is given in Table 1. ALH and ALM lambs were also choice-fed with ad libitum access to feed L. 8 lambs at the start of the experiment and 4 lambs per treatment at 6 and 12 weeks were slaughtered for analysis of body protein (PR), lipid (LP) and wool protein (WP).

The passive transfer of immunoglobulins from colostrum is essential to protect neonatal lambs against infection until their own immune defense systems are fully developed. Adequate intakes of immunoglobulins must be achieved within the first 24h after birth because thereafter “gut closure” precludes any further antibody uptake. The degree of protection afforded is likely to be influenced by suckling frequency, colostrum intake and colostrum immunoglobulin concentrations. Two studies were therefore undertaken, the first to determine the extent of variation in colostrum IgG concentrations in a typical commercial flock of sheep, and the second to investigate the inter-relationships between suckling behaviour and IgG transfer in neonatal lambs.

Experiment 1. Colostrum samples were taken from both the left and right teats of 55 twin bearing Mule ewes immediately after lambing in January, and their IgG concentrations determined.

Experiment 2. The IgG content was measured in colostrum samples collected from both the left and right teats of 10 twin bearing Mule ewes immediately after lambing in March. In addition, a 10ml blood sample was also collected from the jugular vein of each lamb 36h after birth and subjected to IgG analysis.