Some recent studies (Frutos et al, 1992; Giraldez et al, 1993) comparing Spanish sheep breeds have indicate possible differences between breeds in the digestive diet utilization. The aim of this study was to compare voluntary food intake and diet digestibility in three sheep breeds when offered three levels of concentrate supplementation.

A latin square trial (3x3x3) involving three sheep breeds and three levels of concentrate in three periods, with three replicates was designed. The breeds compared were Merina (39.83±10.05 kg live weight (LW)), Churra (44.33±9.86 kg LW) and Assaf (55.83±7.65 kg LW) and three non-productive ewes of each breed were used. All animals were divided into three groups of three animals (one ewe per breed) and housed in individual pens with free access to water and mineral blocks.

Some recents studies (Manso et al., 1993; Iason and Mantecon, 1992) have indicate changes in dimensions of digestive tract in response to pattern of nutrient supply during lamb growth. The extent of this changes could be influenced with the age or stage of maturity at wich the different feeding strategies are applied (O 'Donovan, 1984; Ryan, 1990) and could affect the digestive diet utilization during lamb growth. Knowledge of variation of digestive diet utilization can help in developing strategies to optimize the use of feedstuff by animals.

The objetive of this work was to study the effect of level of intake during milk fed period and undegradable protein content in the diet during post-weaning period on the apparent digestibility of postweaning diet in Churra lambs two weeks after weaning and at 20 Kg live weight (LW).

In Mediterranean countries weaning is an important decision both in meat and milk production systems. In previous work, using the Lacaune milk breed, unweaned lambs produced meat of better eating quality. In this study our aim was to determine the effect of weaning on carcass, meat and fat quality in a breed with a smaller milk production and in animals with free access to concentrate practically from birth.

West Java sheep are permanently housed and offered manually-harvested grass at 50-60 g dry matter [DM] per kg live weight [M] daily [d]. Flocks (ca. 5 head) are housed on slats, with excreta and feed refusals composted underneath.

In a previous experiment (Tanner et al 1993) with 18-month old Javanese Thin-Tailed rams, intake of cut-and-carried, indigenous grass increased as the amount offered was increased (25, 50 or 75 g DM offered/kg M.d; intakes were 22.1, 31.7 and 34.9 g DM/kg M.d respectively). Output of compost also increased with increasing amount of grass offered. In another experiment (Tanner et al 1994) supplementing grass offered at 30 g DM/kg M.d with rice bran fed at 30 g/kg M0.75.d achieved the same intake of digestible organic matter as unsupplemented grass offered at 60 g DM/kg M.d and reduced feeding costs by 15%. However, output of compost was reduced by 41% by rice bran supplementation, resulting in an unacceptable reduction in compost monetary-value.

The aim of this trial was to quantify the variation in growth and lamb meat quality between entire male and castrated male lambs reared under traditional grass systems, and to identify the possible problems in rearing mixed sex groups together. Much work has been carried out on the effects of castration on meat quality and growth (Butler-Hogg et al. 1984; O' Riordan and Hanrahan, 1992), and on pelt removal (Andersen et al.; 1991a, 1991b); this experiment set out to ascertain whether entire male lambs would finish quicker than wether lambs off average condition grass swards in a semi-commercial situation and therefore to determine the necessity of castrating lambs that will be finished by September.

There is great variation in lamb carcass quality due to there being many breeds and crosses involved in lamb production. Breed of lamb appears to influence the pattern of development of the important carcass components, and thus the carcass quality, when comparison is made at equal weights. Plane of nutrition may also affect the growth rate, carcass composition and eating quality of lambs of the same genotype. It was planned to study the effect of both breed and diet on growth performance, carcass and meat quality characteristics by feeding two different diets to the lambs of two different breeds similarly managed from birth to slaughter.

In preparing potato chips for the fast food industry a proportion of the material produced is rejected. Although the composition of these partially-fried chips would suggest that the chips should be fed to non-ruminant livestock, the bulky wet nature of the material precludes this option for many. Therefore a substantial proportion of the chips produced are fed to ruminants especially to growing cattle. Little is known about the rumen digestion of such materials. The aim of the experiment was therefore to evaluate potato chips as a ruminant feed.

Peptides are intermediates in the conversion of ingested protein to ammonia in the rumen and their presence in rumen fluid is influenced by the nature and amount of protein in the diet (2). Transient accumulation of peptides occurs after feeding and then their concentration declines (1,6). However, it is not clear what properties of natually occuring peptide moieties result is increased resistance to degradation in the rumen (5). The objective of this research was to investigate the effect of altering the dietary sources of available energy and protein on the accumulation of peptides in the ruminal fluid.

The value of the goat for milk and meat production has been recognized especially for arid zones, where these ruminants can use natural resources. When goats under grazing conditions are supplemented, changes in milk yield, according to type of supplement, are expected.

This experience was carried out with the aim to study the effect of type of supplement on milk production under grazing conditions.

A total of 48 adult Alpine goats were allocated into four groups (12 goats/group) according with the type of supplement offered:

Group A: 600 g /head/day of a concentrate mixture with high protein content (Soybean + barley grain + maize grain + mineral-vitamin supplement).

Group B: 600 g barley grain /head/day.

Group C: 600 g hay /head/day.

Group D: no supplement.

Extensive research has been focused on advancing the breeding season of the ewe but little is known about the duration of the natural breeding season and if this is influenced by previous breeding management. Lambing percentage declines after the winter solstice but it would appear conception rate is maintained or improved (King, 1990). Oestrus cycles also appear to become naturally synchronised at this time giving a compact lambing without the use of teaser rams or exogenous substances. The objective of the present study was to determine the effect of management history on the onset and duration of ovarian activity in the commercially important Mule (Bluefaced Leicester x Blackface/Swaledale) ewe and on ovulation rate measured on three occasions during the natural breeding season.

There is increasing interest in the development of later lambing systems for crossbred ewes which more closely match ewe nutritional requirements with herbage growth (Stone, 1988; Mitchell, 1990). It has long been recognised however that at extremes of the natural breeding season fecundity is reduced, a possible consequence of seasonal variations in ovulation rate, fertilisation and/or embryo survival (Hammond, 1944). Daylength is the factor which entrains the endogenous rhythm of reproduction in sheep (Donovan, O’Callaghan, Karsh, Boland and Roche, 1992) and daylength changes per se may be responsible for variations in reproductive response throughout the breeding season. Associated environmental and management factors may also be of importance. The objective of the present study was to determine the effect of management history and month of mating on ovulation and lambing rates in Mule ewes.

Many shepherds hold the view that the majority of lambings occur at night, particularly in the period just before dawn. Systematic studies of the timing of parturition in extensively managed ewes demonstrate a circadian pattern but reports differ with regard to the timing of peak incidence. Wallace (1949) found that peak incidence occurred between 00.00 and 04.00 hours confirming the traditional view. However George (1969) found that peak incidence for Dorset Horn ewes occurred during daylight hours.

Under intensive management ewes are typically housed in artificially illuminated pens for the entire lambing period and are under continual observation. The objective of the present study was to investigate diurnal variations in the timing of parturition in ewes under such conditions.

Gastrointestinal parasitism presents a major constraint on livestock production, resulting in reduced animal performance and welfare. Resistance to gastrointestinal parasitism in sheep, as measured by faecal egg count, is heritable suggesting that selection for increased resistance may be used as a longterm control measure, in addition to existing management strategies. Predicting likely responses to selection for resistance gastrointestinal parasites is a challenging problem, however, because (i) interactions between animals affect the expression of disease resistance traits, and this contravenes the assumptions normally made when predicting responses to selection and (ii) disease severity within a population is rarely shows a Normal distribution, and in the case of gastrointestinal parasitism typically shows a negative binomial distribution. This paper outlines a model which may be used to describe likely responses to selection for resistance to gastrointestinal parasitism in sheep, and presents results obtained from this model.

The level of protein degradability in ruminant diets, notably in the peri-ovulatory period and during the early weeks of gestation, can significantly affect conceptus survival and may even interfere with normal control of foetal growth. For example, high levels of rumen degradable protein (RDP) increase embryonic mortality in superovulated sheep but, paradoxically, also have been linked with foetal and neonatal oversize in a small number of cases (Bishonga et al, 1994; Animal Production 58: 447). The present study examined whether there was any evidence of altered development at the early pre-implantation stage in ova derived from ewes offered high levels of dietary RDP in the form of urea, and also investigated the possibility of systemic and local micro-environmental effects in vivo.

The production of cashmere from goats is one of the most promising options for hill sheep farmers wishing to diversify. Not only is cashmere, the down from the secondary hair follicles, a valuable commodity but goats’ grazing preferences can benefit pasture management and ecology. Because no economically viable breeds of cashmere bearing goats are indigenous to the UK, goats were imported from Iceland, Siberia, Tasmania and New Zealand and an extensive crossbreeding programme involving these genotypes and native feral goats was undertaken to produce genotypes suitable to Scottish conditions (Bishop and Russel, 1994). At the completion of this crossbreeding programme the best means of continued improvement of the existing cashmere goat population was considered to be selection for genetic merit, based on an index combining traits of economic importance. This paper summarises responses to the first two years of this selection.

Methionine is a sulphur-containing essential amino acid which is frequently deficient in animal diets. A number of reports have indicated positive responses to the addition of methionine to the diet of ruminants in the form of protein or the individual amino acid. Protection against degradation by rumen microorganisms is necessary in addition to availability for absorption in the small intestine.

The two major genotypes of fine fibre-producing goats are the Angora breed which produce predominantly mohair and those which produce cashmere from secondary hair follicles. Fibre production by primary follicles in Angora goats is limited whereas ‘guard hair’ production in cashmere producers is generally susbtantial.

The object of the present study was to compare the response of the two genotypes to the incorporation of a ruminally protected intestinally available methionine supplement in the diet.

In single-coated animal species selected for fibre production, such as sheep and Angora goats, nutrition is known to have a positive effect on fibre length and diameter, and hence on the weight of fibre produced, while in double-coated species, such as the cashmere goat, the fibre characteristics of the undercoat appear relatively insensitive to nutritional influence. Recent studies on the relationship between nutrition and fibre production in the llama, a double-coated species, indicate that it conforms to the above generalisation in that the growth rate and diameter of its fibre are not amenable to nutritional manipulation (Russel and Redden, 1994). There is a lack of information on the effects of nutrition on fibre characteristics and production in the other domesticated species of South American camelid, the single-coated alpaca. The experiment reported here was designed to provide such information.

The experiment formed part of a development programme to improve tethering practice and increase liquid milk production from grazed goats on smallholder farms. A local survey in upland (Mgeta) and lowland (Mlali) districts near Morogoro (Sendalo, Mtenga, Ngapongora, Minde, Owen, Romney and Gill, 1994) indicated that goats were tethered at sites of grazing for 4 to 8 hours (h) daily (d), with the animals being housed, generally without additional feeding, at other times. The survey also indicated that tethering was a particularly common method of controlling grazing during the wet, crop-planting/crop growing period.

The experiment therefore compared the milk production of lactating goats tethered to graze during the wet season for 4 or 8 h per day. An attempt was made to measure intake during grazing. The experiment tested the hypothesis that goats tethered to graze for 4 h/d would be unable to consume as much grass as those grazed for 8 h/d and consequently, would produce less milk.

Cashmere growth is seasonal with the majority of fibres entering a resting phase (telogen) in the winter prior to shedding in the spring. Daylength appears to be the main cue for shedding, operating primarily through prolactin (Lincoln, 1990 ; Dicks et al., 1994), but there is evidence that nutrition may influence the timing of the moult in a range of species (Ling, 1970). Yeates (1958) demonstrated a nutritional effect on the moulting of the coat in beef cattle with high levels of nutrition advancing the moult and regrowth of the replacement coat and while it has been suggested that nutrition may affect the moult in goats (McDonald et al., 1987; Ryder, 1966), there is as yet no published evidence. Shearing prior to moulting is one of the methods of harvesting cashmere and may itself have a profound influence on the moulting of the stubble and subsequent regrowth. Wool growth may be reduced locally in response to cooling of the skin, but shearing may also increase wool production when associated with increases in voluntary food intake (Bottomley,1979). An experiment was therefore conducted to examine the effects of nutrition and shearing on the timing of the moult in cashmere goats. This paper reports some preliminary results.

The growth of a fine undercoat (cashmere) in goats is a seasonal phenomenon; growth generally begins during the autumn, continues into the winter and is followed by a moult in the spring. The endocrine mechanisms involved in the control of these processes are unclear but the thyroid hormones have been implicated in the control of fibre growth (Ferguson, Schenckel, Carter and Clarke, 1956; Lincoln, Klandorf and Anderson, 1980) and in the normal seasonal cycle of reproductive activity in sheep (Follett and Potts, 1990). However, it is not known whether or not the thyroid hormones have a role in the mediation of photoperiodic effects on secondary hair follicle activity in goats.

Most of the metabolic activity of the thyroid hormones is thought to be attributable to triiodothyronine (T3) which is primarily derived from thyroxine (T4) by a process of monodeiodination. This process can be inhibited by treatment with methylthiouracil.

The aim of this study was to suppress the synthesis of T3 and so to determine whether or not it has a direct role in the control of seasonal variation of secondary hair follicle activity and cashmere growth and moulting.