Bioactive forages such as chicory (Cichorium intybus) or tanniferous legume sulla (Hedysarum coronarium), have been reported to lower the parasite intensities or faecal egg counts (FEC) of parasitised ruminants (Waller and Thamsborg, 2004). To our knowledge, there is no report studying the effects of these forages on established worm populations when grazed in combination. This knowledge could guide us towards optimum grazing management using special forage species as de-worming paddocks. The aim of the present study was to use the bioactive forages alone or in combination for a short period to test their effects on established T. circumcincta adult population in sheep. The tested bioactive forages were chicory and sulla, with grass/clover (Lolium perenne/Trifolium repens) providing the control forage.

Lamb mortality represents a major loss to the sheep industry with up to 10% of lambs born dead and a further 12% dying from birth to weaning (Dawson and Carson, 2002). Supplementing ewes in late pregnancy with fish oil has been demonstrated to improve lamb vigour at birth (Capper et al., 2002). However, Annett et al. (2004) observed that fish oil supplementation severely reduced colostrum yield and lamb output at weaning. The aim of the current study was to evaluate the effect of level and source of fish oil on ewe and lamb performance in order to minimise the negative effects on colostrum production and performance up to weaning.

Perennial ryegrass varieties bred to express high water-soluble carbohydrate (WSC) concentrations have been shown to improve liveweight gain in pre-weaned lambs of grazing ewes (Lee et al., 2001) compared to conventional ryegrass. Studies have shown that the largest differential in WSC between ryegrass varieties bred for high WSC concentrations and control ryegrasses occurs 5-6 weeks after the plant is allowed to re-grow following cutting or grazing (Miller et al., 2001). Therefore, the benefits, in terms of lamb performance, of using these grasses with high WSC concentrations may be best achieved when they are rotationally rather than continuously grazed. The aim of this experiment was to compare lambs rotationally or continuously grazing either a ryegrass variety bred for high WSC concentrations or a control ryegrass.

Adipose tissue becomes more saturated and less unsaturated with age (Kemp et al., 1981). Desaturation of stearic acid to the oleic acid is catalysed by stearoyl-CoA desaturase (SCD) and increasing the degree of desaturation of lamb is likely to be beneficial in terms of human nutrition. By altering the levels of ovine SCD mRNA, the supply of oleic acid to the tissue could be manipulated, resulting in a practical method of changing the fatty acid profile of the animals meat. Previous work in our laboratory has shown variability between adipose tissue depots in their expression of SCD and that this variability is associated with changes in oleic acid content (Daniel et al, 2004). Such differences in SCD expression between depots implies that there may be even larger variation in SCD expression between breeds. A sheep breed with particularly high level of SCD mRNA could then be exploited through breeding programmes to produce animals with increased desaturase activity and therefore increased oleic acid content. Three sheep breeds, Texel, Beulah and Soay, were therefore used to study the influence of breed and age on SCD expression.

Concentrate mixtures fed ruminants generally are composed by cereals where phosphorus is present mainly in phytate form or phytin (Maga, 1982). Phytate phosphorus is thought to be completely available to ruminants due to the presence of phytase enzyme that hydrolyzes phytate phosphorus making it available for absorption. Researches have shown that this fact is not always true, depending on different conditions (Park et al., 2000). The aim of this paper was to study the influence of phytate phosphorus on calcium availability.

Traditional sheep producers in the South European countries fed lambs with concentrate, in order to obtain light carcasses of young animals. As a consequence of this lamb production system, large grazing areas have been abandoned. However, some producers are taking into consideration the extensive grazing systems to reduce costs and at the same time to obtain subsidies established by the Common Agricultural Policy of the EU. Moreover, the increasing demand of healthy and safe meat products is stimulating the interest in pasture-based production systems. However, in our dry mountain conditions, this grazing system can be associated to poorer ewe and lamb performances. The present study sought to compare the productive parameters of ewes and lambs obtained in four different management strategies.

Churra Tensina is a coarse-wooled hardy breed usually managed in semi-extensive systems in Spanish Pyrenees. Grazing natural meadows in spring together with lambing season could be involved in the alternatives of its production system. The aim of this experiment was to study the effect of dietary supplementation of lambs on grazing behaviour of Churra Tensina ewes and their lambs during lactation in natural meadows.

The lambs production system in the South-European countries is characterised by producing light carcasses (< 13 kg) of young animals, less than 90 days old, and fed with the ewe milk and supplemented with concentrates. However, there is an increasing concern on the study of forage production system in growing lambs as a consequence of the interest in diversifying products and producing healthy and safe meat. When forage is included in the fattening diet a reduction of average daily gain is observed and carcasses have a lower degree of fatness, in comparison to the drylot system. The modification in the traditional type of carcass must be evaluated in order to assure that the final product meets the consumer demands. The objective of this experiment was to evaluate the effect of the lambs fattening system on the carcass characteristics and meat quality especially on the instrumental analysis traits as colour and texture.

The use of oilseeds is an important option for increasing the energy density of ruminant diets, in addition to supplying dietary protein to support high rates of production. Ruminal degradation of dietary feed CP is an important factor influencing ruminal fermentation and AA supply to dairy cattle. Ruminal protein degradation is described most often by first order mass action models. One of the more complex of these models is the Cornell Net Carbohydrate and Protein System (CNCPS). In the model, feed CP is divided into five fractions (A, B1, B2, B3 and C) which sum to unity. The five fractions have different rates of ruminal degradation. Fraction C contains proteins associated with lignin and tannins and heat – damaged proteins such as the Maillard reaction products. The remaining B fractions represent potentially degradable true protein. Glucosinalate levels in the rapeseed meal reduce its feeding value as it makes meal unpalatable and toxic to animals. Several studies suggest that certain oils primarily through changes in peripheral deiodination of the inactive hormone thyroxine (T4) to the active hormone triiodothyronine (T3).

Reproductive performance of ewe lambs is lower than that of adult ewes (Quirke 1979). This is mainly the result of preimplantation losses, which can exceed 50% of fertilised eggs. Previous evidence from this laboratory suggests that these losses may be associated with abnormal ovarian hormone production (Davies and Beck 1993). Khan (1999) demonstrated that blood progesterone levels during the oestrous cycle and pregnancy were lower in ewe lambs than in ewes. Furthermore, both progesterone and oestradiol concentrations were lower in ewe lambs, than in ewes, following gonadotrophin stimulation (Khan, Beck and Khalid 1999). These results suggest that ewe lamb corpora lutea and follicles secrete less progesterone and oestradiol, respectively, than those of ewes. The aim of this study was to determine whether there is a difference in vitro steroid hormone production by corpora lutea and follicles, from ewe lambs and ewes.

Fats in the diet can influence reproduction positively by altering both ovarian follicle and corpus luteum (CL) function and by increasing precursors for the synthesis of reproductive hormones such as steroids and prostaglandins (Mattos et al., 2000). Fat supplementation positive effects include: increased size of the ovulatory follicle, increased numbers of ovarian follicles, increased plasma concentration of progesterone, reduced secretion of PGF2α, increased lifespan of the CL, and improved fertility (Staples et al., 1998). Lucy et al. (1992) suggested that it was fatty acids, and not the additional energy provided by the fatty acids, that stimulated ovarian function. Recently, new information has been published that demonstrates that the type of dietary fatty acids is important as individual fatty acids do not have the same effects on reproduction of the dairy cow (Petit et al., 2001).The objective of this study was to determine the effects of dietary supplemental fat source on reproduction parameters in Iranian fat-tailed ewes.

Grazing of barley as green forage is a common practice in the Mediterranean area due to its active growth along autumn and winter, and its ability to recover after a mild grazing (Bonachela et al., 1995). However, grain production at harvest might be affected depending on the intensity of defoliation suffered by the plant (Yau, 2003). Those studies were carried out mainly by hand clipping or allowing only a few hours of grazing per day. Hence, the objective of this experiment was to establish the relationship between grazing intensity and grain production at harvest when animals are kept in the paddocks for the whole day. Moreover, the ability of barley height and/or residual biomass after grazing (kg dry matter/ha) to predict final grain production was also tested.

Cassava root meal is a fine powder from the manufacture of chips and/or starch. Their disposal increases otherwise environmental pollution and health hazards. Nevertheless, ruminants can be fed on cassava tuberous roots, foliage, peel and residue obtained after processing cassava including cassava meal. Evidence so far shows that cassava meal is good source of energy which, when fortified, promote positive and high performance in cattle, sheep and goats. Cassava meal contains high level of energy and has been used as readily fermentable energy in the rations. However, the lack of nitrogen supplied from cassava meal that it is important to include nitrogen sources to balance the energy-nitrogen supply for the microbial activities in the rumen. The objective of this experiment was developing the new products from cassava meal namely, CASMEREA (cassava meal + urea) or commonly name “starea” or “casarea”.

Although some aquatic plants have been used for ruminant diets in some parts of Turkey there is a lack of information about their nutritive values. The aim of this study was to determine the chemical composition and metabolisable energy (ME) content of four different aquatic plants using in vitro gas production technique.

The addition of monensin to lambs feeding diets containing a high proportion of grain of results in improved feed efficiency (Joyer et al., 1979) and in some cases, increased daily gains (Calhoun et al., 1979) but thiamine deficiency can be a serious problem when high carbohydrate diets are fed (Loew, 1975). The objective of this experiment was to provide additional information on the possible benefits of the addition of monensin and thiamine to Mehraban male lambs fed with a high concentrate diet.

Limited studies on evaluation of the nutritive value of sugar beet seed (Beta vulgaris ) waste (SBSW) and its application in beef or lamb production have been carried out in its producing countries. SBSW is one of the side products of sugar beet seed which approximately a quarter of seeds can not be used in cultivation and is considered as waste. Consisting of 17% whole seeds and the rest as cracked seeds or hulls, SBSW contains 14.5, 32.5, 1.3, 16.9, 27.5, 39 and 49.9 percent CP, CF, EE, NFE, CF, Ash, ADF and NDF respectively. Also, SBSW contains 3.20 Mcalkg-1 Potkanski and Urbaniak (1985) reported an improved average daily gain (ADG) and feed conversion ratio (FCR) in comparison to wheat straw because of its better essential amino acid index, which is close to wheat grain, but there is no report on its effects on fat tail composition. This trial was performed to examine SBSW replacement effects in fattening Chal lamb rations.

Saffron (Crocus sativa, SF) and Madder (Rubia tinctorum, MD) are planted for their stamen (used in food industry) and roots (used for dyeing) in northeast and central Iran respectively. Artemisia siberi (AR) is also a typical plant of the arid and semi-arid areas in Iran. The forage parts of these plants have been used as ruminant feedstuffs for many years. However, little is known about the nutritional value of these forages and so information about their composition and degradability characteristics is necessary in order to properly balance their use in ruminant diets. The objective of this study was to determine the chemical composition and extent of digestion of DM and OM of these plants compared with grass nuts (GN) as a reference feed by using an in vitro method (Chaudhry et al., 2002).

Ration formulation systems require information on nutrient requirements of the animal and reliable values for rumen degradable and undegradable fractions of feed ingredients. Ruminally degraded protein in excess of microbial requirement results in nitrogen loss as ammonia and inefficient nitrogen utilization by ruminants. Protein degradation kinetics of most oilseed meals and some forages have been determined (Sadeghi et al., 2004; Wilkerson et al., 1995), but minimal information exists regarding ruminal protein degradation of pasture forages. The objective of this research was to determine ruminal dry matter (DM) and crude protein (CP) degradation kinetic parameters of eight pasture species.

Inclusion yeast in the diet of ruminants increases the density of active metabolic cells in rumen. These cells can stimulate the action of special kinds of microorganisms in the digestive tract (1). One of the most outstanding ability of yeast is to stimulate the cellulytic bacteria of rumen (7). Increased initial rate of cellulose digestion by yeast can improve the efficiency of feed and make available more nutrients for growth and milk production (2, 3). Furthermore, improved ruminal digestion may increase feed intake, and this effect specially for voluminous feed which are less consumed because of the physical limitation resulted from filled rumen is more prominent(7). On the other hand enhanced bacteria population of rumen may result in increased synthesis of microbial protein and may increase the incorporation of microbial population in digestive tract. Lower concentration of ammonia in the rumen indicating incorporation of ammonia into microbial protein is the direct result of stimulated microbial activity (3, 4, 5, 6). This paper reports the effects of yeast culture Saccharomyces cervisae (1026) on ruminal fermentations and blood metabolites of an Iranian native breed of sheep.

Despite of high production of barley in Iran, its use in poultry diets is limited due to low energy content and problems such as sticky droppings. Barley cultivars have different nutritive value for broilers (Villamide, et al., 1997) and enzyme application may affect barley cultivar based diets differently. β-glucanase supplementation of barley based diets can eliminate β-glucan, the main anti-nutritional factor of barley, and improve nutrient digestibilities and apparent metabolizable energy. The objective of this trial is to study the β-glucanase effect on nutrient digestibilities and apparent metabolizable energy corrected for nitrogen (AMEn) of different barley cultivar based diets.