Recent studies carried out in cattle, sheep and goats have shown differences between both species and breeds of ruminants in digestive capacity, digesta flows and fermentation rates. Most of these differences are related to their feeding behaviour and digestive physiology and could affect digestive utilization of feeds. The aim of this work was to study the digestibility and digesta kinetics in the whole digestive tract in two breeds of sheep (Churra v. Merino).

Ten non-productive mature sheep (five Churra (mean LW= 44.3kg±3.20) and five Merino (mean LW= 46.7kg±2.22)) fitted with rumen cannulae were used in this study. Animals were fed once a day 1 kg of alfalfa hay (877 g DM/kg; 169 g CP/kg DM; 489 g NDF/kg DM).

Several treatments for increasing digestibility of sugarcane bagasse (SCB) have been studied in Brazil for many years (Abdalla et al., 1990). Despite some improvements in in situ digestibility obtained with steam and pressure treatments, the SCB has not performed well when given to cattle (Mello Junior, et al., 1989). More recently, irradiation and ammonia has been tested in studies to improve the digestibility of SCB, rice and corn straw, rice and soybean hulls and others rough feed. The purpose of the present experiment was aimed to determine the intake, body weight changes, wool production and microbial synthesis in sheep fed with grass hay (Cynodon dactilon) or SCB treated with 600kGy of radiation and ammonia (20g/kg dry matter (DM)).

Recognition of the importance of the native sheep breeds as one of the main source of meat in Iran has led to several studies on their growth performance. There is little information available on the animal potential of Sangsary sheep, a native Iranian breed. The aim of this trial, therefore, was to assess the growth potential and carcass quality of Sangsary male lambs.

Forty four entire males, 9 month (m.) old, mean initial weight 26.8 (sd 2.5) kg were used. The two diets, which consisted of concentrate and roughage, had a similar protein content (150 g CP/kg DM) and metabofisable energy of either 10.6 MJ/kg DM (diet A) or 9.2 MJ/kg DM (diet B), were each fed ad libitum to 22 lambs. The animals were group penned. At the start and end of the study, the animals were weighed on two consecutive days.

Voluntary food intake is generally inversely related to body condition or fatness in mature sheep (Foot, 1972). Since the intake of pelleted diets by housed sheep consists of a number of discrete feeding bouts or 'meals' (e.g. Bermudez et al., 1989), the relatively long-term effect of body condition on intake will be achieved through changes in feeding behaviour at the level of a single meal. The aim of this experiment was to compare the effects of body condition and short-term food restriction on meal patterns in sheep, to investigate the mechanism by which body condition influences daily food intake.

A supply of sulphur-containing amino acids is essential for the growth of hair fibre in animals.The main sulphur-containing amino acid quantitatively required for the synthesis of fibre protein is cystine or its monomeric form cysteine,which may be absorbed from the digestive tract or converted from methionine via the transulphuration pathway.The predominant sites of the transulphuration pathway in ruminants are the liver (Radcliffe and Egan,1978)and the heterogenous system in the skin (Downes et al,1964).The aims of the study were to determine the importance of the supply of cystine and methionine for the growth and viability of the cashmere secondary hair follicle in vitro and to investigate whether cystine could successfully be replaced by methionine in this homogenous system.

The feeding of ewes in late pregnancy is critically important because this is a period of high foetal growth rate. Feed blocks have been used to replace compound feeds in both hill and upland flocks but there is limited information available on block-feeding to lowland flocks.

To evaluate the replacement of trough-feeding with self-help feed blocks, for housed ewes fed good quality grass silage during late pregnancy, and to lactating ewes at grass.

The ruminal digestion of protein results in the production of peptides (3) which are an intermediate step in the conversion of ingested protein to ammonia. Low molecular weight peptides can also act as substrate for tissue metabolism (2). While it has been shown that low molecular weight peptides are present in ruminant blood (4), their hydrolysis rate has not been investigated. The following in vitro study was conducted to investigate the disappearance rate from blood and rumen fluid of sheep of two different dipeptides; glycylproline and glycylphenylalanine.

The nutritive value of a given ruminant feedstuff is best evaluated using the combination of chemica analysis, in vitro and in vivo feeding responses (Van Soest, 1987). Recent studies have further shown that degradation characteristics of foods, gas production characteristics, fibre components and the in vitro dry matter (DM) digestibility (Tilley and Terry, 1963) could be ranked in declining order of reliability as predictors of both intake and in vivo apparen digestibility of feedstuffs (Khazaal et al, 1995). The aim of the study was to evaluate the effect of urea treatment o; sorghum stover (SS) on rumen kinetics and feeding responses by growing Yankasa rams.

Microbial fermentation of lignoceluUosic feeds in the rumen produces 3-phenylpropionic (PPA) and cyclohexanecarboxylic (CHCA) acids. Feed phenolic cinnamic acids are regarded as the main precursors of PPA upon microbial action (Martin 1982b). CHCA can be produced by microbial metabolism of dietary alicyclic compounds such as quinic and shikimic acids (Balba and Evans, 1977; Martin, 1982a). Following absorption CHCA and PPA are subjected to metabolism mainly in the liver yielding benzoic acid (BA) which is extensively excreted in urine mainly as its glycine conjugate hippuric acid (HA). The aim of this work was to assess the quantitative relationship between the urinary excretion of total BA (free BA + HA) and the uptake of PPA and CHCA.

Studies involving infusion of stable isotope labelled peptides have shown that the mammary gland has the ability to utilise peptide-derived AA for milk protein synthesis (Backwell et al., 1994a) and that peptides may be involved in the supply of phenylalanine to the mammary gland in vivo (Backwell et al., 1994b). The aim of the present experiment was to compare milk production responses to systemic (jugular vein) provision of histidine as free AA or as a peptide (glycyl-histidine) in lactating dairy goats with an induced histidine deficiency.

Low conception rates in high producing dairy cows have been linked to the feeding of excessive quantities of rumen degradable protein (Elrod & Butler, 1993). Similarly, a recent study in non-lactating ewes, superovulated during seasonal anoestrous, has shown that high rumen degradable protein intakes throughout the preovulatory and early pregnancy period have an adverse effect on embryo survival (Bishonga et al., 1994). The present study aimed to identify the window of oocyte/embryo development which is sensitive to variations in the degradability of maternal protein intake in naturally cycling ewes expressing their normal ovulation rate. Nutritional treatments were applied at three crucial developmental time points spanning (1) preovulatory oocyte maturation (2) fertilisation and early cell division in the oviduct and (3) entry of the embryo into the uterus, hatching and the transition from a spherical blastocyst to an elongating conceptus.

Increasing concern over the role of greenhouse gases in global warming has led to a renewed interest in models for predicting methane production in ruminants. We have previously shown that data generated in sheep may be of limited use in predicting the effect of diet on absolute methane production by cattle (Newbold et al., 1995). However, sheep may still be a viable model for evaluating methods of reducing methane production by cattle. As dietary lipids may inhibit ruminal methanogenesis (Moss, 1993), we have now compared the effect of coconut and linseed oil on methane production by both sheep and cattle.

The development of in vitro culture techniques (Ibraheem et al, 1993, 1994) for the study of caprine hair follicles has proved useful in elucidating aspects of the control of cashmere and mohair fibre production. There is a similar need to investigate nutritional and other factors which regulate the growth of sheep wool. The aim of the present study was to develop an in vitro technique to study the role of the B-vitamin biotin in controlling growth and viability of sheep wool follicles.

Oxalic acid is present at high concentrations in certain plants such as Beta vulgaris L. and Rumex spp. and may cause renal toxicity following consumption by ruminants. Oral dosing of animals with free oxalic acid leads to an increase in the rate of oxalic acid breakdown in the rumen (Allison and Reddy, 1984). However, information is lacking on the extent to which the rate of administration of oxalic acid affects the capacity of ruminants to degrade the compound. Moreover, different species with different foraging habits may show different ability to detoxify the oxalic acid.

This experiment was carried out in order to determine the extent to which the rate of exposure to oxalic acid affects the capacity of the rumen of sheep and goats to degrade the compound.

Previous research conducted on bulls, rats and man have shown that selenium-deficient animals produce less viable semen than animals of an adequate status, because the tail of the spermatozoa is a seleno-flagellate (Slaweta et al., 1988). Furthermore, the fertilising ability of ram spermatozoa is reduced in liquid nitrogen as the semen quality is affected by osmolality and the freezing and thawing process (Colas and Guerin, 1981). In a small experiment, the effect of selenium supplementation on low-selenium rams was tested to ascertain the quality and viability of fresh ram semen and the post-thaw recovery and fertilising ability of frozen semen.

Recent work has reported that synchronising the hourly supply of energy and nitrogen to the rumen can improve the efficiency of microbial growth by 12-14% (Sinclair et al., 1995). However, animals when offered an asynchronous feed ad-libitum may alter their pattern of intake to achieve a more synchronous release of nutrients in die rumen. In addition, the provision of concentrates at fixed times may alter the hourly and daily intake of forage and the pattern of release of nutrients in the rumen. In a previous experiment with growing sheep (Sinclair and McQuiston 1995), grass silage was demonstrated to have an asynchronous release of energy and nitrogen in the rumen and mat the provision of concentrates did not alter the pattern of silage intake but increased the degree of synchrony.

A major limitation to the success of genetic improvement programmes using multiple ovulation and embryo transfer is the failure to generate sufficient viable embryos per donor ewe to maintain selection intensities and sustain a low generation interval. Seasonal anoestrus imposes a biological constraint on embryo production in many breeds of sheep. The objective of this study was to investigate the response to superovulation during seasonal anoestrus (April - May) in Scottish Blackface ewes.

The development of laparoscopic intrauterine insemination for sheep has been essential for the implementation of national Sire Reference Schemes in the UK (McKelvey and Simm, 1995). Whilst conception rate to artificial insemination (AI) has averaged 60-70% in most participating flocks, a number of flocks have experienced a proportion of their ewes returning to anoestrus following AI. This phenomenon restricts the implementation of sire reference schemes and it has been proposed that die causal factor could be the presence of a persistent corpus luteum at the time of insemination.

The handling of animals by their keepers, particularly in early life, has been shown to influence the subsequent behaviour and performance of various domestic farm species (Lyons, Price and Moberg, 1988; Hemsworth and Barnett, 1992). When production systems require animals to be handled frequently and in situations where their collaboration is essential, such as dairying, then the animals' placidity and tractability becomes essential. The aim of the experiment was to establish if handling goat kids for a few weeks after birth would influence behaviour when they were subsequently milked.

Heart rate has been successfully recorded in sheep, deer and pigs (Baldock and Sibly, (1986) Price, Sibly and Davies, (1993) Webster et al, 1995). This work has shown that resting heart rate can increase in stressful situations. Being able to record heart rates of group-housed sows would complement behavioural observations, if it could be shown that the presence of the monitor did not alter group behaviour. The aim of this study was to assess in a group of active sows, the effect of the presence of a heart rate monitor on behaviour.