Current suggestions for the upper limit for the total gucosinolate content of oilseed rape are around 20 μmol/g of seed, which corresponds to a level in the de-fatted meal of approximately 33 μ mol/g. Information about the suitability of this material for incorporation in growing pig diets is required by the UK feed industry. When attempting to provide the required information the presence of factors such as tannins, sinapine and phytate in rapeseed meal should be considered, as must the high (≈ 120 g/kg) fibre content of the material. This experiment was designed to examine growing pig performance from 30 to 75 kg liveweight when fed diets containing increasing levels of rapeseed meal at both fixed and increasing glucosinolate contents.

Continued developments by plant breeders in the selection of rapeseed varieties with lower levels of antinutritive and toxic factors, especially glucosinolates in double-low varieties, has recently seen the commercial introduction of triple-low varieties. The characteristic yellow-coloured hulls of these newer types of rapeseed are considered to contain lower concentrations of other antinutritive factors found in the darker hulls of double-low cultivars. It is uncertain whether this has led to corresponding improvements in the nutritional value of the solvent extracted oil-free rapeseed meal (RSM) which is fed as protein supplement for livestock. This experiment was conducted to compare meal extracted from triple-low with that from double-low rapeseed as a protein supplement completely replacing soya-bean meal (SBM) in finishing pig diets.

Winter feed represents a major cost in the production of suckled calves. By using the summer grazing period to ensure that cows are housed in good body condition winter feed can be restricted. The controlled weight loss of cows through the winter subsidises food inputs (WRIGHT, RUSSEL and HUNTER, 1986). At High Mowthorpe a mixture of barley and urea (BU) has proved to be a cheap and successful supplement to ad-lib wheat straw as a winter ration for suckler cows. Rapeseed meal (RSM) and maize gluten (MG) are possible alternatives to BU. RSM and MG have two potential advantages in that they may be cheaper to purchase and that they eliminate the need for milling and mixing facilities. Provided cow performance is not adversely affected RSM and MG could offer scope for simplifying ration preparation and reducing winter feed costs.

Dry season feed for ruminants is characterised by a shortage of energy and protein. Technology for improving the utilization of crop residues may not be available because of shortages of money or inputs. Chemical treatment, supplementation and handling of stovers available in Zimbabwe has been studied.

Lambs were allocated to treatment by blocking according to live weight and then randomizing within blacks. Three weeks acclimatisation was followed by intake measurement over 7 days and digestibility over 5 days.

In several recent studies it has been shown that growing pigs and sows can digest substantial amounts of plant cell wall polysaccharides (non-starch polysaccharides (NSP)) by microbial activity in the intestines (for example, see Longland and Low, 1988). Furthermore, it is clear that the principal products of the fermentation, acetic, propionic and butryic acids, are absorbed and used as energy substrate for growth (Bulman et al, 1989). Of the sources of NSP that have been examined, sugar beet pulp is particularly well digested, and it was used in the present study. The objective of the work was to measure the development of the capacity of the intestinal microflora of piglets, after weaning at 21 d, to digest sugar beet pulp. At the same time the performance of the piglets from 21 to 56 d was assessed.

One of the disadvantages in using field beans (Vicia faba) has been the presence of tannins which form insoluble complexes with proteins, enzymes and carbohydrates. This experiment evaluated zero-tannin, white-flowered varieties and tannin-containing, coloured-flowered ones, in terms of the utilization of energy and nitrogen by broiler chicks.

A basal diet was designed to give sub-optimal levels of protein (70% of requirement, ARC 1975). The 5 bean varieties were incorporated into the basal diet at 4 rates (Table 1). Three of these were white-flowered with negligible levels of tannin (Albinette, 0.006g/kg; Blandine, 0.005g/kg; and Albatross, 0.010g/kg) and two were coloured-flowered and contained significant levels of tannins (Minden, 0.138g/kg; and Alfred, 0.113g/kg). Methionine and lysine were subsequently added in quantities sufficient to ensure they were not first limiting. The 16 diets were fed to Cobb broiler cocks of 7 days initial age (4 replicates of 2 birds per cage).

Measurement of N disappearance during the incubation of a feed in polyester bags in the rumen is a widely used procedure for determining the ruminal protein degradability characteristics of the feed. These can then be used in conjunction with measurements of rumen outflow rate to calculate the expected extent of degradation in the rumen, which is a necessary prerequisite for diet formulation. Using the polyester bag procedure rates of feedstuff protein degradation have been found to be lower when cereal diets are given than when forage diets are given. Whilst this has been attributed to lower levels of cellulolytic activity in the rumen of cereal-fed animals it has also been suggested that it may be due to the physical nature of the rumen contents causing blockage of the bag pores. In the present study the effect of feeding either an all-forage or a high-cereal diet on polyester bag-derived and in vivo estimates of soyabean meal (SBM) protein degradability in the sheep rumen was examined.

It is probable that the degree of saturation of fat may modify the response to increasing Free Fatty Acid (FFA) content and of apparent metabolisable energy (AME). The objective of the current study was to investigate the effect of FFA content on the AME value of soya bean oil.

Soya bean oil (A) and soya bean acid oil (E) with FFA content of 14.4 and 683.4 g/kg fat respectively and of similar fatty acid composition, were obtained for evaluation (Table 1). Fats A and E were then mixed in proportions 75A:25E, 50A:50E and 25A:75E to give three blends of calculated FFA content of 181.7 (B), 348.9 (C) and 516.2 (D) g/kg fat respectively. All fats were included into a basal diet (Table 2) at 40, 80 and 120 g/kg and were evaluated with broiler chicks aged 1.5 weeks and 7.5 weeks of age. Apparent metabolisable energy (AME) values of fats was achieved by regression of apparent fat availability (AFA) on rate of inclusion of fat with extrapolation (linear functions). AME was determined as a product of AFA and fat gross energy.

In Bangladesh, locally produced fishmeal is available as a protein source of lactating cows but there is a need to find an alternative concentrate such as a legume browse which can be grown on small farms. An experiment has been carried out to assess the effect on performance of partly replacing fishmeal with fresh foliage from Sesbania sesban.

Previously, sugar beet feed (SBF) was thought to be of limited value for feeding to growing pigs due to its high fibre content. Maximum inclusion rates recommended were 5 and 10 per cent for pigs from 20 to 45 and 45 to 90 kg live weight respectively (MAFF, 1986). However, the fibre is highly digestible and more recently Longland et al (1988) showed that replacement of cereals with SBF may be possible up to levels of 15 and 30 per cent for pigs of 20 and 75 kg live weight respectively. It was also shown that the performance of older pigs fed SBF was enhanced if SBF was introduced into their diets at an early stage. The work was undertaken on individually housed pigs over a wide range of inclusion rates. The experiment reported here investigated the effect of providing SBF to group-housed pigs from 15 to 35 kg live weight and its effect on subsequent performance during the finishing stage. A further objective was to determine the optimum inclusion rate of SBF when fed to finishing pigs.

Hay is an increasingly scarce commodity on cattle farms in the UK, due to the transition to silage in recent years. However it is generally preferred by farmers for feeding to calves because it is easy to transport and to feed in small quantities without rapid deterioration. A commonly used alternative is straw, and the voluntary consumption is as high as hay (Kang and Leibholz, 1973), but the DM digestibility is low and high levels of straw in the diet depress empty body weight gain (Thomas and Hinks, 1982). Mixing straw with palatable feeds of high nutrient content, such as molasses, has been shown to increase its feeding value to that of silage for older cattle (Phillips and Leaver, 1985), and could increase the forage intakes of young calves, where palatability is important in determining intake. Maintaining a high forage intake could also reduce the incidence of deleterious oral behaviours, such as licking the pen.

A three years field experiment in practical management conditions was carried out at La Poveda Field Station with the aim of establishing the relationship between allowance and intake and estimating the overall efficiency of the grazing system.

A paddock grazing management system was implemented with grazing time restricted to eight hours per day. 90, 98 and 98 lactating ewes of the Hanchega breed in its spring lambing season were used in 1985, 1986 and 1987 respectively.

Manchega ewes grazing sown irrigated pastures during the autumn or spring lambing season were or were not supplemented with up to 1 kg ewe-1 d-1 of on-farm supplements (barley and field beans) until mid-lactation with the aim of assessing the influence of practical concentrate supplementation on milk yields and milk composition. Milk samples were taken at 15-day intervals from seven days after lambing.

The Highlands and Islands Development Board (HIDB) is developing a strategy for the production and marketing of high health breeding sheep. Farmers and crofters in the North of Scotland, with HIDB support, have formed the Highlands and Islands Sheep Health Association (HISHA) to produce and market high health sheep. HISHA has over 500 members with a total of 250,000 breeding ewes. Members’ flocks are monitored by the Scottish Veterinary Investigation Service for Enzootic Abortion of Ewes (EAE) and for vaccination against Clostridial Diseases and Pasteurella. A requirement for information on the sheep health concerns and experiences of the potential purchasers of high health breeding sheep was identified. A survey was undertaken of lowground sheep farmers in Grampian and the Borders of Scotland to provide this information.

The objectives were to determine, firstly, lowground sheep farmers’ concerns on sheep health; secondly, their experience of sheep disease problems; and thirdly, their awareness of sheep diseases that can be introduced by wintering sheep for another farmer or through purchased sheep. The survey was carried out by postal questionnaire and the Department of Agriculture and Fisheries for Scotland (DAFS) prepared a mailing list from their census records. The DAFS also undertook the despatch and receipt of the questionnaires to preserve farmer confidentiality. The data was analysed using the Scientific Information Retrieval Data Base Management Systems analytical package.

Chile's X region (40-43 degrees south), has around 1 million has. of marginal soils with forest-livestock potential use, red clay slopes being dominant, located in the coastal ranges. Subsistance agriculture with increasing erosion damage is carried out on small properties which also practice extensive livestock production with sheep and cattle.

In order to study alternative land use which could benefit small peasant farmers agroforestry with sheep and pines was attempted.

Two agroforestry systems using Pinus radiata D.Don and sheep were developed. System I started in 1977 planting 8 ha at 2,5 x 7m spacing. Romney ewes were introduced in 1979 initially at a stocking rate of 5/ha. Prunnings were carried out in 1980, 1984 and 1986; thinnings were done in 1982,1984 and 1986, to 7m and 200 st/ha respectively.

System 2 used 20ha of conventional 2 x 2m forest planted in 1974. It was prunned and thinned in 1982,1984 and 1986 to Bm and 200 st /ha respectively and stocked initially with 4.7 Romney ewes/ha in 1983.

Wahed and Owen (1986) showed that intake of barley straw by goats increased when the amount of straw offered was increased from 18 to 54 and 90 g dry matter (DM) per kg mass (M) daily. The three offer rates were associated with refusal rates (% of offer) of 14, 57 and 70 % respectively. Subsequent work at Reading by Allmon et al (1989) indicated that goats were selecting more straw-leaf when offer rates were Increased.

The present study, undertaken in Ethiopia, investigated whether similar responses would occur with sheep offered increasing quantities of sorghum stover (straw) and whether the responses would vary according to variety of sorghum. Dry-land farmers In Ethiopia and other African countries are being encouraged to plant new varieties of sorghum which are more bird-resistant than the traditional varieties. Unfortunately bird-resistant varieties have been shown to contain polyphenolic compounds which may have adverse effects on intake and digestion of stover. Two contrasting varieties of stover were therefore compared in the present study.

During both food restriction and subsequent re-alimentation of sheep, the proportion of empty body weight formed by the gastro-intestinal components has been shown to change (Winter, Tulloh and Murray, 1976; Murray and Slezacek, 1988). The extent and nature of compensatory growth depends on the composition of the diet during restriction (Wilson and Osbourn, 1960). This study investigates the effect of rumen undegradable protein in the diet, during food restriction, on these processes. The hypotheses tested were that the protein:energy ratio of the diet during restriction to constant liveweight (LW) influences the relative proportions of the components of the digestive tract and its overall size as a proportion of empty body weight (EBW) a) during restriction and b) during subsequent growth on realimentation.

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. The objectives of the present trial were:

• (i) to compare the growth performance of spring and summer born lambs grazing swards fertilised with a high level of nitrogen or oversown with clover and receiving no fertilizer nitrogen.

• (ii) to investigate relative declines in midseason growth rates.

Manipulation of seasonality in the ewe has been the subject of extensive research over the past few years. Demand for continuous supply of home-bred lamb has encouraged producers to breed their ewes both earlier and later in their natural breeding season. Extending the breeding season to a Summer (May/June) lambing has proved a low input system reducing the requirement for concentrate feeding in late pregnancy and eliminating the need for housing during the winter period (Stone, 1988). However, Summer lambing involves mating ewes in January when fecundity may be declining. Exogenous Melatonin has been shown to be effective in advancing the breeding season by extending the length of time that significant levels of Melatonin are present in the blood. It may also have a beneficial effect on embryo survival (Wigzell et al, 1986; Kennaway et al, 1987). In Summer lambing ewes, where endogenous Melatonin is in decline during tupping in January, the introduction of exogenous Melatonin may result in continued reproductive activity and aid implantation of embryos.

It has been clearly established that shearing ewes during pregnancy increases lamb birthweight (Austin and Young, 1971; Rutter, Laird and Broadbent, 1971; Black and Chestnutt, 1990). Fewer studies have examined the response of fattening lambs to shearing although both Salman and Owen (1981) and Marai, Nowar and Bahgat (1987) noted a significant increase in growth rate. This was accompanied by an increase in voluntary food intake and consequently little change in the food conversion efficiency.

The objective of these experiments was to study the influence of shearing on voluntary food intake and growth rate of fattening lambs offered various levels of concentrate feeding plus ad libitum forage.