Supplementation of silage diets with fish meal (a low rumen degradable protein) has resulted in increased live-weight gains in steers (England & Gill, 1985). This response has been attributed to increased dietary protein escaping degradation in the rumen and being digested in the small intestine. Fish meal however is expensive in monetary terms. More recent work (Jacobs and McAllan, 1992) showed that rapeseed meal (a highly rumen degradable protein) supplementation of silage diets given to growing steers resulted in significant increases in live-weight gains similar to those obtained with fish meal supplements. The response to rapeseed meal was probably a result of enhanced microbial protein synthesis in the rumen as a result of synchrony of available energy and nitrogen nutrients, thus increasing microbial (and hence) total protein flow to the small intestines, producing a similar overall response to fish meal. The object of this experiment was to further evaluate the use of rapeseed meal as an alternative to fish meal

Two silages, 60D (low digestibility, L) and 70D (high digestibility, H) were prepared from minimum wilt first cut perennial ryegrass (mixed sward). The grass was cut with a disc mower and picked up with a precision chop harvester.

Recent trials with cows fed grass silage have shown significant increases in intake and in yields of milk and milk solids when the crude protein (CP) concentration in a supplementary concentrate was raised. Giving additional CP in the concentrate was a more effective strategy for improving yields of milk and milk protein than giving extra energy (Aston et al 1992). The objective of this trial was to examine the influence of changes to the amount and pattern of distribution of CP supplied in a fixed concentrate ration given with grass silage ad libitum.

Fifty-five Holstein-Friesian cows in their second and subsequent lactations were given a standard diet for two weeks from calving and then were used in a continuous feeding trial from weeks 4 to 21. The cows received 5 kg of fresh concentrate daily containing 156 (LP), 245 (MP) or 338 (HP) g CP per kg dry matter (DM), MP comprised equal amounts of LP and HP. Concentrate carbohydrate sources were cereals and digestible fibre and CP was increased by a mixture of 3:1 soya:fish meals. Grass silage contained 253 g toluene DM/kg, 162 g CP/kg DM, D value in vivo 0.723, pH 3.7, fermentation acids 135 g/kg DM of which 0.85 was lactic acid and NH3-N 91 g/kg total N.

Within conventional silage finishing systems, forage quality is critical to lamb performance and some concentrate feeding is generally required (Fitzgerald, 1987). Rate of finish may also be manipulated by increasing the concentrate component of the diet, particularly in the latter stages of the finishing period. For organic production however, the United Kingdom Register of Organic Food Standards (UKROFS) limit concentrate supplementation to 40% of daily dry matter intake, and a flatter pattern of concentrate allocation is generally required. Where diets containing a high proportion of clover (more likely under an organic or low nitrogen system) are fed, improvements in lamb performance have been shown in grazing animals (Clark, 1988) and following ensiling (Vipond et al, 1992). The aim of this experiment was to assess the potential of high clover silage to finish hill lambs from the organic unit at ADAS Redesdale.

One hundred and forty four approximately six month old Scottish Blackface wether lambs (mean liveweight 30.0 kg, se = 0.24) were housed off silage aftermath and assigned (in pens of twelve) to one of three treatments - grass silage plus 400 g concentrate (GH), high clover silage plus 400 g concentrate (CH) or high clover silage plus 200 g of mineralised barley (CL).

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, Owen, Winugroho & Gill, 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.

Cutting and carrying grass is labour demanding and therefore expensive. Substituting some of the grass with a readily available by-product such as rice bran could reduce feed costs.

In the present experiment, cut-and-carried grass was supplemented with rice bran and the effect upon intake of grass and output of compost measured.

Sesbania, a tropical legume browse, provides green foliage high in crude protein and low in crude fibre (Sen, Ray and Ranjhan, 1978). In Bangladesh two varieties of sesbania, Sesbania aculeata and a recently introduced African Sesbania rostrata are largely cultivated for green manuring in agricultural fields during kharif season. The leaves of sesbania may be used as good source of protein to supplement protein-poor roughages in ruminants diets. However, there is an extreme paucity of information on its nutritional value for goats. An attempt was therefore made to study the effect of feeding sesbania leaves as sole feed on growth performance and nutrient utilization in growing Black Bengal goats.

Nine Black Bengal male castrated goats aged about 5 months and weighing 9.0 kg on average initially were used in a 56 day study.The goats were housed individually in a slatted floor and were introduced to the experimental feed over a period of 2 weeks.The animals were allocated at random to one of three dietary treatments in a randomised block design according to live weight.The control group A given road-side grass and the groups B and C offered green leaves of Sesbania aculeata and Sesbania rostrata, respectively.

The fibre fraction (= non-starch polysaccharides; NSP) of tropical forage legumes is a potentially important source of dietary energy. Such legumes, however often contain tannins which can reduce the fermentability of the NSP fraction. In this study, the monosaccharide composition and in vitro digestibility of the NSP fraction of eleven tropical forage legumes varying in condensed tannin content, were investigated.

Milled, lyophilised leaves of 5 species of forage legume from Ethiopia, Sesbania goetzei (SG), Sesbania sesban (SS) Leucaena leucocephala (LL), Acacia cyanophylla (AC), Chamaecytisus palmensis (CP)) and six from Colombia, Calliandra sp. 29400 (C), Dioclea guianensis (DG), Flemingia macrophylla 77409 (FM) Tadehagi sp. 23227 (T23), 13269 (T69) and 13275 (T75)) were used. One gram samples were fermented at 39°C for 7 d under anaerobic conditions in modified Van Soest medium inoculated with bovine rumen fluid (5 replicates per species). At the end of the fermentation period, residues were filtered, washed with distilled water and lyophilised. The NSP content and composition of the original samples and their residues were determined by the method of Englyst and Cummings (1984). The bound, soluble and total condensed tannin contents of the original samples were determined by the method of Terrill et al. (1992).

The engulfment and digestion of bacteria by ciliate protozoa leads to elevated ruminal ammonia concentrations and reduced microbial protein flow from the rumen. Thus it has been suggested that the removal of protozoa from the rumen (defaunation) may be beneficial in animals fed low protein diets (Bird and Leng, 1978). However, existing laboratory methods for defaunation are unsuitable for practical usage. Here we investigated the effects of leaves from various African multipurpose trees (MPT) on the activities of rumen bacteria and protozoa in the hope of identifying naturally occurring defaunating agents.

Protozoa are responsible for over 90% of the bacterial protein turnover in the rumen (Wallace and McPherson, 1987), thus the breakdown of bacterial protein was used as an assay of protozoal activity. [14CJ-Leucine-labelled Selenomonas ruminantium was incubated in vitro with rumen fluid taken from four rumen-fistulated sheep receiving a diet of hay, molasses, fishmeal and a mineral and vitamin mixture (500, 299.5,100,91 and 9.5 g/kg respectively). Wheat straw (40 mg/ml) or a 70:30 mixture of straw and MPT was added 2 h before the addition of labelled bacteria. Samples were removed hourly for up to 4 h to follow bacterial degradation. Unlabelled leucine (2.5 mM) was added to the rumen fluid to prevent reincorporation of [14C]-leucine.

There are major limitations imposed on animal production in tropical areas of the world. Some of the limitations are caused by the lack of availability of protein for animal consumption. This lack of dietary protein can be attributed to lack of pasture because of adverse environmental conditions, overgrazing which can lead to erosion and thus a poorer environment, poor soil condition and nutritional status. Often, grazing of mixed pastures and the provision of cereal crop residues are the fundamentals of ruminant nutrition in most tropical countries. These dietary substrates are frequently N-deficient and also frequently very high in fibre which limits digestibility. Such a dietary regime may maintain animals at low levels of production and may prevent their death during prolonged dry periods but good productivity is precluded. The inclusion of legumes, either browse or forage, in pastures can reduce or alleviate some of the problems mentioned above and provide dietary protein. Leucaena leucocephala has been shown to be a suitable leguminous forage supplement for ruminants in arid areas of the world including Zimbabwe. It is not however without problems thus there is considerable interest in producing different cultivars.

The advancement of ‘self reliance’ in developing counties is essential to their future success. This can be achieved by reducing their dependence on imported products, such as concentrate feeds made from imported materials. If this is to be accomplish alternative feed resources must be identified and developed. In topical environments oil producing plants and leguminous fodder trees are abundant and represent an existing feed resource which can be utilized. These feeds are capable of providing a sustainable alternative to imported feeds, as they are inherent to these environments and economic to produce.

The aim was to assess the possibility of the complete replacement of concentrate with African Palm Oil and Gliricidia sepium.

A total of sixty six cows were used in two experiments which were completed simultaneously on two separate farms. The cows were allocated to the experimental diets 20 days post-partum and the treatment groups were balanced for previous lactation yield, the number of previous parturitions, calving index and condition score.

The nylon bag technique is widely used for assessing the kinetics of forage disappearance in the rumen (Ørskov, Hovell & Mould, 1980); the technique also holds promise for predicting the intake of roughages (Ørskov, Reid & Kay, 1988). The nylon bag technique is being advocated as being especially suitable for tropical conditions where laboratory facilities are limited. However the technique has a capacity limitation. Due to its dependence on in situ incubation in the rumen of fistulated animals, only small numbers of forage samples can be assessed at any one time. Thus the technique is of limited value in laboratories undertaking routine screening of large numbers of samples, for the purposes of feed evaluation and for use in plant breeding programmes.

Forage legumes are a potentially important source of dietary energy and protein for ruminants in the tropics. However, the nutritive value of such legumes can be depressed by their polyphenolic content. The effects of these compounds include inhibition of fermentation in the rumen and complexing with enzymes, dietary protein and fibre.

The aim of this study was to evaluate the relationship between the total polyphenolic (TP), total condensed tannin (TCT), bound condensed tannin (BCT) and soluble condensed tannin (SCT) contents of forage legumes and their fermentability in vitro.

Leaf samples from eleven species of tropical forage legume were collected from Colombia (six species) and Ethiopia (five species). Lyophilised, milled samples of each of the eleven species (1 g x 5 replicates) were placed in gas-tight culture bottles containing an anaerobic medium inoculated with bovine rumen fluid. The cultures were incubated under anaerobic conditions for a total of 7 d h at 39°C.

In the UK the majority of dairy cow diets are based on grass silage and tend to over supply effective rumen degradable protein (ERDP ) as defined by the Metabolisable Protein (MP) system. As a result the nutritionist is often required to make up a shortfall in digestible undegraded protein (DUP) supply, particularly in diets for high yielding cows. Sources of additional dietary DUP fall into two categories: - vegetable or animal in origin. The DUP content of fishmeal is significantly higher than any of the naturally occurring vegetable proteins and the industry has been searching for some time for ways of improving the DUP content of vegetable proteins.

In a novel treatment process soyabean meal is incubated at low temperature overnight in a solution of lignosulphonate. The treated meal undergoes a maillard reaction which reduces the extent of degradability in the rumen but does not affect digestibility in the small intestine.

Milk protein synthesis may be limited by amino acid (AA) flow to the duodenum. This can be increased by increasing the flow of microbial AA's or undegraded feed AA's. This experiment was carried out to determine the effect on milk production and nutrient flows at the duodenum of including fishmeal (120g/kg) in the supplement to grass silage at two levels of supplement feeding.

The treatments, arranged in a 2x2 factorial, were 1.) 3.5 kg/day of 0% fishmeal supplement (L-UDP), 2.) 7 kg/day of L-UDP, 3.) 3.5 kg/day of 12% fishmeal supplement (H-UDP), and 4.) 7 kg/day of H-UDP. Supplements were fed to 3 6 Friesian cows in a 4x4 multiple Latin-square trial with three week periods to determine production responses, and to four ruminally and duodenally cannulated cows to determine rumen fermentation and nutrient flows. Flows were determined by the dual marker technique of Faichney (1975) using cobalt-EDTA and ytterbium acetate as liquid and solid phase markers respectively. Purines were used as the bacterial marker (Zinn and Owens, 1986). Degradability of the feeds was measured in 3 other cows using the small bag technique described by De Boer et al. (1987).

The production of organic milk as defined by UKROFS (United Kingdom Register of Organic Food Standards) requires set production standards, the registration of approved producers and a minimum conversion period before the sale of the product. During the period when a farm is being converted to organic milk production the change from using large quantities of inorganic fertiliser to the establishment of swards containing white clover can reduce both the stocking rate and total milk output (Houghton and Poole, 1990), reducing the income from the farm.

An experiment was designed to study the effects of both grazing to pre-determined sward heights and feeding a concentrate supplement on the stocking rates and milk production of a spring-calving dairy herd.

Restricted suckling systems are one the most common forms of livestock production in developing countries. In these systems partial milk extraction and calf suckling are combined, resulting in a multi-commodity (milk and meat) production system. These are now being recognised as some of the most efficient and sustainable uses of the available resources in developing countries. These systems provide a more ‘natural’ method of calf rearing, thus maximising animal welfare.

The aim of this experiment was designed to investigate the maternal relationship between cow and calf within a restricted suckling system and evaluate its effect on milk production and reproduction.

In tropical countries it is common practice to milk cows once daily and additionally maintain a suckled calf. Such a system in Europe could have relevance on small farms where part-time work was necessary to maintain the farm business.

The objective of this study was to examine the cow and calf performance on such a system in comparison to a conventional twice daily milking system.

Sixteen Holstein Friesian cows (12) and Brown Swiss x Holstein Friesian cows (4) were allocated at random to control or suckled groups. They calved in June/July 1992 with beef bred calves (Simmental and Limousin sires). Calves were removed from the control cows at 24 h after birth.

They were grazed until October as two separate groups and buffer fed with maize silage. The control group were milked twice daily and the suckled group were milked in the morning only. The calves were put with the suckled group after morning milking and were removed from their dams 7-8 h later and housed overnight. After full housing in October, the calves were allowed to suckle for up to 30 minutes after morning milking and for a further 30 minutes in late afternoon.

There are now a range of new breeding technologies which are actually or potentially available for use in commercial dairy cows. In order to give a socioeconomic evaluation of these new technologies the effects of the achievable genetic lift and gain must be estimated and their effect upon milk production. This paper has evaluated these effects from both artificial insemination and embryo transfer based technologies.

A simulation model was constructed to estimate the consequences of adopting either A.I. or embryo based technologies on milk production. The model simulated a 100 cow herd over a period of fifteen years, to allow the delayed benefits of using such technologies to reach maturity. The initial herd structure was calculated using a range of estimates of technology success rates (probability of successfully conceiving after one service) and culling rate (14%).

Previous studies have shown that using non-invasive techniques such as the measurement of the velocity of ultrasound (VOS) through live animals (Sim. 1983) can, in the body of the lactating dairy cow, provide reliable estimates of chemical composition and energy content (Ivings,Gibb,Dhanoa and Fisher.1993). In this study VOS was used to monitor the changes in body composition of dairy cows fed concentrates containing differing levels of crude protein (CP).

Fifty-five Holstein-Friesian cows were offered 5kg of fresh concentrate containing 156(L),245(M) or 338(H)g CP/kg dry matter (DM) together with grass silage (162g CP/kg DM,D value 0.723,ME 12.3 MJ/kg DM and pH 3.72) offered ad-libitum over weeks 4 to 21 of lactation. There were five treatments designated LL,LH,MM,HL, HH with a change of CP level where appropriate in week 13. Five cows were selected from each treatment and VOS measurements taken from two sites on the hindquarters (B and Bl) at weeks 12,15,18 and 21. Liveweights were also taken at this time.

Tse-Tse flies inhabit over 11 million km2 of Africa and are vectors of trypanosomes which cause trypanosomiasis in domestic livestock. The disease has a negative effect on productivity and is fatal in non tolerant breeds. The effect of nutrition on response to the disease was studied.

Thirty two N'Dama heifers (initial mean liveweight 113 + 17.0) were offered ad libitum andropogon hay plus 10.2 g/kg LW groundnut hay (GNH) (L) or GNH and 3.9 g/kg LW groundnut cake (GNC) (H). After 4 weeks on diet, half of each group were inoculated intradermally with trypanosomes (T. Congolense) (LI and HI). Intake was measured daily and liveweights weekly, while thrice weekly blood samples were examined for parasitaemia and packed cell volume (PCV).

Existing grassland-based male beef production systems use 200 to 300 kg N/ha and require 9 to 11 t silage plus 700 to 1200 kg concentrates per animal produced. Output is in the range 700 to 800 kg carcass per ha. Arising from the reform of the Common Agricultural Policy (CAP) of the European Union, such beef production systems must be extensified if all the animals are to qualify for the special beef premium. The reformed CAP specifies a maximum stocking density of 2 livestock units (LU) per ha whereas existing systems operate at an intensity of 2.5 to 2.7 LU per ha. The objectives of the present study were (1) to extensify beef production (from dairy bred calves) so as to obtain more production from grazed grass and less from silage and concentrates and (2) to measure the effects of reduced fertiliser N usage on herbage production, stock carrying capacity and animal performance.