Farmed red deer (Cervus elaphus) are highly seasonal animals, showing a marked winter inappetance followed by excellent growth from turnout in spring. The quality of grazed herbage has been demonstrated to have a significant impact upon growth during the grazing season. For example, performance is improved by the provision of a sward surface height of 8 - 10 cm compared with a sward height of 5 - 6 cm (Davies et al, 1998). The objective of this study was to assess whether deer performance could be further enhanced by providing white clover (Trifolium repens) swards (C) either in early, late or throughout the grazing season compared with perennial ryegrass (Lolium perenne) swards (G).

Concentrate finishing systems for store lambs often involves a dramatic change in the basal diet as lambs are moved from being managed on, e.g. grass and / or roots to concentrates. If this is done too quickly there is a risk of digestive disturbances leading to acidosis and secondary infections. Hence, the selection of the carbohydrate balance between starch and digestible fibre is crucial as ruminants fed high levels of starch-based concentrates can develop sub-clinical acidosis and liver abscess, leading to decreased voluntary food intake and daily live weight gain (DLWG). The aim of this study was to evaluate two concentrate formulations for effective growth for finishing of Swaledale lambs, one concentrate being starch biased the other digestible fibre biased.

Concentrate finishing systems for store lambs often involves a dramatic change in the basal diet as lambs are moved from being managed on, e.g. grass and / or roots to concentrates. If this is done too quickly there is a risk of digestive disturbances leading to acidosis and secondary infections. However, the desire of the lamb finisher is to transfer the lambs onto the concentrate diets as quickly as possible and reduce rumen friendly materials such as straw to maximise performance. Yeast products have been shown repeatedly to reduce the production of lactic acid and stimulate the utilisation of lactic acid by certain rumen microflora, e.g. M. elsdenii leading to a more optimal rumen environment for the rumen microflora that in turn enhances nutrient supply and animal performance.

The aim of this trial was to determine whether there would be any response to the inclusion of two yeast products, a live yeast, Yeasacc 1026 and a yeast culture, Diamond V XP, in intensively finished Swaledale wether store lambs.

The n -alkane technique (Dove and Mayes, 1991; Mayes and Dove, 2000) has been developed as a method to determine the voluntary intake of herbivores grazing freely at pasture. The technique relies on the fact that each herbage species contain a unique profile of odd-chain n -alkane compounds within the cuticular waxes of each plant part. Whilst some n -alkane profiles for the major intensively managed herbage species are available, there is little comprehensive information on the n -alkane profiles of many of the herbage species found commonly in semi-natural vegetation communities (SNVC) in the hills and uplands of the UK. If the n -alkane technique is to be extended for use with herbivores grazing SNVC’s, it is necessary that such profiles be determined. This study details the n -alkane concentrations found in ten herbage species sampled from SNVC’s in the UK during late summer in 2000.

Energy and protein supply during the dry period can affect subsequent milk production and composition (Moorby et al., 1996). Grass silage is a common ingredient of dry cow diets, but although it is usually adequate in crude protein concentration (CP), a high proportion is frequently in non-protein forms. Red clover silage has shown interesting characteristics that would increase true protein supply to ruminants (Broderick et al., 2000), which could avoid the use of more expensive concentrate supplements. The objective of this experiment was to compare red clover and ryegrass silage when fed as the sole source of forage to dry cows with a diet comprising ryegrass silage and a protein supplement.

Animal domestication is a natural selection experiment the important result of which is a great increase in the rate of appearance of new forms and in the wild range of variation of organisms. Analysing different aspects of this problem, D.K. Belyaev has came to a hypothesis that the morphological and physiological reorganisation of domestic animals has been going by the way of unconscious selection of animals on their behaviour, carried out by person at the very first stages of domestication (Belyaev, 1979). To testify this hypothesis, a population of tame silver foxes has been produced in long-term selection for lack of aggression and fear towards humans (domestic behaviour) at the Institute of Cytology and Genetics in Novosibirsk, Russia. In the process of selection the genetic transformation of behaviour and morphology, and physiological functions has been observed (Trut, 1999). In particular, selected animals show no aggressiveness to man, behave amicably towards humans and have some changes in the coat colour and body constitution (Trut, 1999). The important part of Belyaev’s hypothesis was the assumption that selection for domestic behaviour could affect the reproductive function, in particular the pituitary-gonadal axis controlling reproduction and fertility. The aim of this study was to obtain information about possible changes in reproduction between control (C) and domesticated (D) vixens. Reproductive performance, potential fertility, embryonic mortality and fetal viability were analysed for vixens from domesticated and control population. In addition, plasma progesterone concentrations were determined in selected and control females during pregnancy.

The selection of dairy cattle for high milk production is thought to be linked to increased problems with fertility. Most research has concentrated on the influence of actual yields rather than the effect of genetic merit on fertility. It has also been reported that by maintaining a high level of herd management the reproductive efficiency problems associated with high milk production can be removed (Nebel and Gilliard, 1993). The current work estimated the influence of genetic merit (defined as PIN95), 90-day daily milk yield, deviation from herd mean 305-day milk yield and body condition score on fertility, in an attempt to assess whether actual yield has more effect than potential yield as indicated by genetic merit.

The main cause of prolonged post-partum anoestrous in suckled cows is the failure of dominant follicles to ovulate. Increased LH pulse frequency is necessary to promote dominant follicles (DF) to ovulate. A 96 h period of calf removal lead to a 2-fold increase in the LH pulse frequency in the study of Stagg et al. (1998). Moreover, acute calf isolation and once-a-day suckling shortly after the emergence of the fourth follicular wave induced two thirds of cows to ovulate the ΔF of that wave (Sinclair et al., 1999). The present study was carried out to investigate the effect of 96 h calf removal and GnRH administration on the duration of the post-partum anoestrous period in suckled beef cows.

It is now well established that milk progesterone analysis can provide a valuable tool in reproductive management of the dairy cow. With the advent of relatively cheap cow side milk progesterone tests, the principle block to widespread monitoring is the time and effort involved in the actual collection and analysis of the milk samples. This has led to a research drive to develop on line milk progesterone monitoring systems whereby progesterone is routinely monitored at normal milking. Near-infrared spectroscopy (NIRS) is widely used in the agricultural industry for analysing cereals and forages and is used for on-line testing in the food and pharmaceutical industries. Vibrations of chemical bonds between carbon, oxygen, hydrogen and nitrogen atoms affect the amount of near-infrared light absorbed at individual wavelengths, so different molecules show unique patterns in the spectrum. These patterns are related to determined concentrations of chemicals in calibration samples to develop equations that predict concentrations in unknown samples. This project set out to assess the use of this technique to measure milk progesterone.

The plasma urea nitrogen (PUN) can be an indication of the quantity and degradability of the protein consumed. The high serum concentration of PUN may reduce fertility by local toxic effect on either the sperm, the ovum or the developing embryo (Jordan and Swanson, 1979). The objective of this study was to investigate the effect of high concentration of PUN following the increase of crude protein (CP) intake on ovarian response and fertilisation rate of superovulated ewes.

For the effective use of Artificial insemination technique in sheep industry, investigation on the methods of ram semen dilution and freezing is necessary. Ahangari (1992) showed that various rates of dilution from 1:1 to 1:4 did not affect p>0.05 post thawing survival of Cambridge ram spermatozoa. Fiser et al (1987) achieved a 73% c.f. 67% pregnancy rate using thawed semen, previously frozen to -100 and -79 respectively. The objective of this study was to investigate the effect of two rates of dilution of semen and two methods of freezing on post-thawing motility of ram spermatozoa.

There is substantial evidence that the increased consumption of fat by dairy cattle can result in an increase in the number ovarian follicles, and the number and size of corpora lutea; it also stimulates post-partum ovarian activity and improve pregnancy rate. Increased dietary lipid also increases plasma cholesterol and progesterone, and the supply of lipoproteins which play significant roles in regulating ovarian steroidogenesis (Willimas, 1996). In contrast to cattle, there are few observations on the effects of dietary lipid on reproductive function in sheep. Intravascular infusion of lipid into ewes stimulated progesterone and prostaglandin synthesis (Burke et al., 1996), and dietary supplementation of calcium soaps of fatty acids enhanced luteal function (Kuran et al., 1999). Calcium soaps of fatty acids have been manufactured in Iran in recent years and sold under the trade name of Megalac. The aim of the present experiment was to study the effects of this protected fat on follicular number and luteal activity in two fat-tailed sheep breeds.

After prolonged exposure to tanniniferous diets, it has been reported that some rumen microorganisms acquire defensive mechanisms against tannins (Brooker et al., 2000) or produce tannin-degrading enzymes. Such rumen microorganisms are said to be “tannin resistant” as their fermentation activity is less inhibited by the presence of tannins in the host’s diet. As acacia pods contain tannins their use as protein supplements for goats in the dry season may require that they be first detannified e.g. by using polyethylene glycol (PEG). However, goats with prior exposure to tanniniferous diets may have developed adaptive mechanisms to deal with tannins. This study, therefore, investigated the need for tannin inactivation in feeds given to ‘adapted’ animals by comparing the effect on the in vitro fermentation of tree pods incubated with and without PEG using rumen fluid from adapted and unadapted goats.

Brazil has arid regions where livestock production is limited by forage source. However, some native herbaceous legumes have a dry tolerance and had been used as animal feed. Some of those plants have anti nutritional compounds such as tannins that and can interfere on intake and digestibility of these plants. Tannins have a high affinity with proteins and could make these molecules unavailable for animal. Compounds as polyvinylpolypyrrolidone (PVPP) have been used on tannin studies, because it has more affinity with tannins than proteins. Based on that, it is possible to evaluate the nutritive potential of tanniniferous plants, using PVPP as an inhibitor of tannin effects. The aim of this work was to evaluate the effect of tannins on in vitro rumen fermentation.

The occurrence of tannins in plant leaves has a widely known ecological significance in terms of both nutritional constraint for animals and litter decay in the soil. However, there is no single protocol for extracting tannins for their subsequent quantification. The use of acetone has the advantage of inhibiting the polyphenol-protein interaction (Hagerman and Robbins, 1987), but becomes an disadvantage when assaying the protein precipitation capacity of the extract in biological assays (Hagerman and Butler, 1991). The objective of the present work was to compare tannin extracting agents and to assess the relationship arising between different solvents.

The occurrence of polyphenolics compounds in forage is of nutritional significance due to its protein binding capacity which can affect protein digestion (Woodward and Reed, 1989). They also have a role in controlling rates of decomposition and N mineralization of plant residues (Swift et al., 1979). The Prussian-blue assay (Price and Butler, 1977) is widely use for quantitative measurement of polyphenol content of plant materials due to the easiness it can be performed. Polyphenols are polar compound and literature report extractions with, methanol, ethanol or acetone as usual solvents. Although it is known that no single protocol is optimum for all samples. No comparison was found between solvents on a wide range of material to assess if results might be correlated. The objective of the present work was to compare the efficiency of four solvents for polyphenol extraction.

Tannin can bind with feed nutrients and they became unavailable to ruminants. The aim of this work was to compare rumen degradability parameters with phenolic compounds of Brazilian ruminant feeds.

In Chiapas, México, natural vegetation is often used for grazing cattle. Local knowledge identify several plants and fruits as been consumed by cattle, But few information is available on their nutritive value. The objective of the present work was to assess the potential nutritive value and biological activity of tannins in 14 materials by means of the in vitro gas production technique.

The use of alternative protein sources in ruminant diets is of interest because of restrictions on the use of animal proteins, loss of nitrogen (N) compounds to the environment and efforts to reduce costs of systems. A problem of some protein-rich-ingredients is that they degrade rapidly in the rumen. The use of tannins has been proposed as a means of reducing the extensive dietary protein degradation in the rumen. However, condensed tannins have been reported to exert detrimental effects on gut microflora and on the gastrointestinal tract, and they can affect post-rumen digestion. The two experiments reported here aimed to study the influence of quebracho tannins (QTs) on ruminal degradation of peas (Pisum sativum) and sweet lupins (Lupinus luteus), and to investigate the effect of QTs on postrumen digestibility of these feeds using a poultry model.

Forage trees are commonly used in the tropics as supplementary feed for ruminants. However, during the dry season where grass is of poor quality, many trees also shed their leaves and are no longer available. Adequate strategies are to be evaluated to allow forage trees to be introduced into feeding systems as good quality supplements along the year. Silage might be an adequate technology if the resultant product allow similar animal performance as those achieved using commercial concentrate as supplement, but few studies have been conducted with forage tree silages. The objective of the present experiment was to evaluate intake, digestibility and microbial-N synthesis of diets supplemented with grains or forage tree silage.