Applications of high concentrations of fertiliser nitrogen (N) to silage swards are known to alter the chemical composition of herbage by increasing crude protein (CP), decreasing dry matter (DM) and altering water soluble carbohydrate (WSC) concentrations. Many studies have illustrated that increasing the CP concentrations of concentrates increases silage intake. However, there is little data available to illustrate the effects, if any, of silage CP concentration on forage intake and animal performance. Information is also lacking on the value of silage CP relative to concentrate CP in terms of animal performance. Therefore the present study was initiated, using different levels of formic acid to equalise fermentation, to evaluate the effects of N fertiliser on silage CP concentration, forage intake, digestibility and animal performance of lactating dairy cattle. It also provided an opportunity to compare the value of silage CP to that obtained from concentrate.

It is generally assumed that lactating dairy cows offered grass silage consume less dry matter than cows offered fresh pasture. The aim of this study was to identify the effect of specific components of the ensilage process on food intake and animal performance.

Thirty-six lactating dairy cows were offered the following diets in a changeover design experiment:

Gl = primary growth perennial ryegrass zero grazed between 11/5/94 and 31/5/94 (high digestibility).

Sl,3 = silage made from Gl and allowed to ferment for 3 weeks prior to feeding.

Sl,9 = silage made from Gl and allowed to ferment for 9 weeks prior to feeding.

G2 = primary growth perennial ryegrass zero grazed between 1/6/94 and 21/6/94 (low digestibility).

S2,3 = silage made from G2 and allowed to ferment for 3 weeks prior to feeding.

S2,9 = silage made from G2 and allowed to ferment for 9 weeks prior to feeding.

Each treatment forage was offered for a period of 3 weeks, with food intake and animal production data from week 3 used in the statistical analysis. Forage was obtained from the primary growth of a perennial ryegrass sward, which had received 135 kg N, 19 kg P2O5 and 38 K2O/ha. All grass was pre-mown with a rotary mower, then lifted using a round baler. Bales were offered directly to the cows or wrapped in black plastic, stored and allowed to ferment. No additive was applied at ensiling.

Fertilisers are usually evaluated by their effects on herbage DM yield and occasionally herbage composition. Rarely are the effects on animal production considered, even though there is evidence for example that increasing the sodium (Na) contents of herbage can increase the milk yield of dairy cows (Chiy and Phillips, 1991), and that dietary sulphur (S) contents in excess of l-2g/kg DM will lead to reduced intake and productivity in ruminants (Raisbeck, 1982). In the UK the use of sulphur fertilizer is widely advocated, since herbage growth is often restricted by deficiency now that industrial emissions have been reduced. Sulphur fertilizer increases herbage S content, but Na fertilizers can affect herbage S content and S utilization by ruminants (Chiy et al., 1994). The effects of Na and S fertilizers were therefore studied with particular emphasis on herbage composition and dairy cow production.

Sward surface height (SSH) has been shown to have an effect on the performance of dairy cows. However, to understand precisely how cows adapt to such differing sward conditions, it is necessary to study the interactions between bite mass, biting rate, and thus intake rate, and time spent grazing. An experiment was therefore designed to examine grazing behaviour and intake by lactating cows at three sward heights.

Restricted suckling is one of the most common forms of livestock production in developing countries. It combines partial milk extraction and suckling, in a multi-commodity (milk and calf) production system.

The objective of this experiment was to determine the possibility of the use of once daily suckling to increase total milk production without reducing reproductive performance or the ‘ quantity’ of milk extracted at milking in crossbred cattle.

A total of 36 cows, locally known as ‘Lucerna’, were placed into two treatments. 18 cows were non-suckled and 18 cows were restricted suckled once daily for 15 minutes following milking (p.m.). All experimental cows had completed two or more lactations and at 3 days post partum were simultaneously allocated to the treatments according to: parity; condition score; previous lactation yield and calving interval. The cows remained in the experiment for 100 days.

In recent years there has been increasing interest in the use of bacterial inoculants as silage additives. A number of recent studies have shown improvements in silage fermentation, feed intake and milk production following the use of inoculant additives at ensiling. Even when compared with well preserved control silages, studies at this Institute have shown that treatment with an inoculant of Lactobacillus plantarum at ensiling has produced positive responses in both silage intake and milk yields (Gordon, 1989; Mayne, 1990). This leads to the hypothesis that, unlike the traditional acid additives, application of an inoculant at ensiling to grass which has been wilted to a high dry matter (DM) concentration may still produce improvements in milk production in comparison with untreated silages. The objective of the present study therefore was to examine if the response to the use of a bacterial inoculant at ensiling was influenced by the wilting of grass.

Dairy cow productivity depends on efficient reproductive performance. A vital element of this is the prompt resumption of ovarian activity, which is normally expected by 35 days post partum. Cows will thus have a period of progesterone priming, which is considered necessary for satisfactory conception and embryo survival. Dry period nutrition has been shown to affect milk production during the subsequent lactation and this study was instigated to examine the possibility that the onset of ovarian activity may also be affected.

Loose housing of sows and their litters during lactation and removal of the need for early weaning offers substantial benefits for both animal welfare and cost of production. However, commercial application of such a system is dependent on achieving early and synchronous pregnancy in lactating sows. It is known that the occurrence of lactational oestrus can be facilitated by the combined stimuli of grouping, a high plane of nutrition and the presence of a mature boar. However these stimuli were only partially successful in inducing synchronised oestrus in an earlier experiment (Hatet et al, 1994). Administration of exogenous gonadotrophin to newly weaned sows has been shown to shorten and reduce variation in weaning to oestrus interval (Lancaster et al, 1985). The endocrine response of lactating sows to exogenous gonadotrophin has been shown to vary with stage of lactation (Britt et al, 1985). In this experiment, the role of these two factors in the successful induction of early and synchronous pregnancy in multisuckled sows was investigated.

Aggression in group housed sows is often related to competition over food. Sequential feeding avoids the confrontations at the trough, but puts them at the feeder entrance. Studies of large groups of dry sows using computerised feeding systems showed that vulva biting was most frequent after visits when only a small amount of food had been dispensed (Buré, 1991). This suggests that frustrated feeding motivation may cause increased aggression. A Swedish survey into group housed sows found a link between sow condition and mean injury scores: farms averaging a high injury score had a larger proportion of thin sows (Svendsen et al., 1990). The present study aimed to investigate the hypothesis that in large dynamic groups of sows a high food level results in lower levels of aggression and associated skin lesions.

Food restricted sows under extensive conditions forage for considerable periods of time and this can give rise to serious pasture damage. This pasture damage can be diminished by the reduction of rooting behaviours. In the past this has been achieved by nose ringing but, due to welfare implications, the emphasis has now been shifted onto alternative methods such as nutritional modification. This rooting behaviour is, in part, caused by hunger (feed motivation) and it has been demonstrated that this feed motivation can be manipulated by short-term changes in food level and type (Brouns et al 1994; Edwards et al, 1993; Ewbank, 1974).

The objective of this experiment was to study the effects of feeding a fibrous diet (containing 600 g/kg unmolassed sugarbeet pulp) either at a restricted or ad libitum level, on foraging behaviour and the consequences of this for pasture damage.

Stereotypic behaviour in pregnant sows is related to food restriction, occurs in the post prandial period (Terlouw, Lawrence and Illius, 1991) and may be linked to continued existence of feeding motivation after a small meal of concentrate food (Lawrence and Illius 1989). Lawrence and Terlouw (1993) suggested that feeding motivation is heightened by positive feedback from the act of eating, while the negative feedback from absorbed nutrients may be insufficient to produce satiation. The resulting foraging behaviour is then channelled towards simple and repeated behavioural acts. In an attempt to manipulate positive feedback signals growing pigs were given a restricted food allowance in one, two or three meals per day and their behaviour was observed during the post-prandial period.

With a growing interest in less-intensive housing systems, pig breeding companies have developed genotypes which are supposedly better suited to these conditions. The aim of this experiment was to compare the performance of progeny from sows of 2 types:

1. a) ‘indoor’ - Large White x Landrace

2. b) ‘outdoor’ - 25% Meishan or 25% Duroc with 50%Large White and 25% Landrace

All sows were mated to a Large White boar and the progeny housed in one of three finishing systems - outdoor paddocks, straw yards or fully slatted pens. The systems were typical of commercial practice, with an automatically controlled natural ventilation system and 0.6 m2 of floor space per pig in fully-slatted pens. Outdoor paddocks and straw yards had minimal environmental control and space allowances of 20.0 m2 and 1.6 m2 per pig respectively. Pigs in outdoor paddocks were retained on cereal stubble with electric fencing and had free access to a bedded shelter hut.

In a companion paper reporting on ‘indoor’ and ‘outdoor’ genotypes of finishing pigs housed in outdoor paddocks, straw yards and fully-slatted pens, materials and methods are detailed along with performance results. The aim of this experiment was to assess the welfare of progeny from both genotypes in these three finishing systems.

For the 6 treatments (2 genotypes x 3 finishing systems), the welfare of each group of 20 growing-finishing pigs was measured using a combination of objective and subjective means.

1. i) Behaviour observations - recording the numbers of animals engaged in each of 5 behaviours at 5 minute intervals for a total of 6 hours (1.5 hours per day for 4 consecutive days). This value of pig minutes was then expressed as a proportion of the total time budget.

2. ii) Mortality / Morbidity records - recording the number of pigs that died or were noted as being diseased or injured following daily inspection, and expressing this as a mean group score.

3. iii) Body Damage scores - at the start and end of the experiment, each animal was restrained within a weighcrate for a few moments to determine levels of body damage (cuts, bruises and scratches) and hind leg bruising of the hock region (bursitis). Using scoring systems adapted from de Koning (1985), and Smith and Smith (1990), a mean injury score was subsequently calculated for each group of animals.

4. iv) Stomach Damage scores - the number and severity of lesions and ulcers in the pars oesophagea region of the stomach were recorded following slaughter and translated into a mean pen score using a graded scoring system (Potkins et al 1989), where 1 = normal and 6 = ulcer.

In the UK, pollution of the water system with nitrate nitrogen leaching from the soil is seen as a major problem and farm animal effluents have been identified as a major source of nitrate pollution. It would, therefore, be beneficial to the livestock producer and to the environment if the nitrogen excretion from animals could be kept to a minimum. To limit the excretion of nitrogen by the pig, it is necessary to supply amino acids in the diet in better agreement with its dietary requirements. This could be achieved either by feeding diets according to the pig's requirements based on age and/or weight (phase feeding) or by improving protein quality. The best protein quality would be that which has the same balance of essential amino acids (EAA) with respect to lysine as that required by the pig, i.e. ideal protein. Diets formulated on the basis of total dietary EAA on an ideal protein basis, using crystalline EAA, could enable lower crude protein (CP) diets to be offered whilst maintaining nitrogen retention (NR). An alternative approach to formulating diets would be to base the formulations on either: 1) currently available, commercial database values for ileal digestible EAA values of ingredients to achieve diets as close to ideal protein as possible but within least cost formulation constraints; or 2) ingredients limited simply to cereals and pulses and supplemented with crystalline EAA to formulate as close to ideal protein as possible. The object of the present experiment was to evaluate diets, formulated on this basis, in terms of nitrogen intake (NI), excretion (NE) and retention (NR) in pigs using balance studies.

In the UK, pollution of the water system with nitrate nitrogen leaching from the soil is seen as a major problem and farm animal effluents have been identified as a major source of nitrate pollution. It would, therefore, be beneficial to the livestock producer and to the environment if the nitrogen excretion from animals could be kept to a minimum. To limit the excretion of nitrogen by the pig, it is necessary to supply amino acids in the diet in better agreement with its dietary requirements. This could be achieved either by feeding diets according to the pig's requirements based on age and/or weight (phase feeding) or by improving protein quality. The best protein quality would be that which has the same balance of essential amino acids (EAA) with respect to lysine as that in ideal protein. Diets formulated on the basis of total dietary EAA on an ideal protein basis, using crystalline EAA, could enable lower crude protein (CP) diets to be offered whilst maintaining nitrogen retention (NR). The majority of the experimental evidence to support the theory of low crude protein (CP) diets comes from either the use of cereals alone with crystalline amino acid supplementation or diets high in maize by-products and low in lysine : digestible energy (Lys : DE) which contrast with the type of diets commonly used in the UK. A series of experiments have therefore been carried out to investigate more thoroughly the possibility of using dietary manipulation, based on diet specifications and ingredients more appropriate to the UK, to reduce nitrogen excretion by the pig, whilst at the same time maintaining the high level of lean gain achieved by UK stock. The object of the present experiment was to determine the effect of isocaloric diets which differed in CP content but had similar levels of essential amino acids (EAA), on nitrogen excretion (NE) and retention (NR) by growing and finishing pigs; these diets being formulated on an ileal digestible EAA (IEAA) basis.

The efficient production of the weaner pig requires accurate knowledge of its amino acid requirements. This is particularly relevant today as it is increasingly important to reduce nitrogenous waste from pigs. During the past decade formulations for feeds were based on the ideal protein profile of the lean tissue of pigs in which the sulphur amino acid requirements were assessed as the combination of total sulphur amino acids rather than through their individual amino acids, methionine and cystine (Agricultural Research Council, 1981). Today, this concept is challenged. The effect of the changing cystine demand in the weaner pig on the total ileal digestible sulphur amino acid (IDSAA) requirements and hence methionine levels requires study. The objective of this experiment was to understand the requirements and relationship between true ileal digestible cystine and methionine to lysine ratio in the ideal protein content of food to achieve efficient production in the young pig.

Full-fat rapeseed (FFR) is a nutrient rich product (containing about 400 g/kg oil and 180 g/kg ideal protein) and is used in pig diets at low inclusion rates (5 to 10%) as an energy supplement. Progress in the development of rapeseed varieties with lower levels of antinutrients and recent changes in subsidy payment have promoted interest in increased feeding of whole milled rapeseed to pigs. At higher levels of dietary inclusion, this may result in the problem of fat softness in the carcass as rapeseed oil contains high levels (32 g/100 g) of polyunsaturated fatty acids (PUFAs). However, this may be avoided by early withdrawal of FFR from the diet to allow mobilisation of PUFAs from body fat before slaughter. The aim was to evaluate the effect of inclusion rate and withdrawal of FFR on the performance and carcass fatty acid profile of finishing pigs.

Inconsistencies in the estimated phosphorus requirements of growing pigs have come to light in recent years due to environmental constraints being imposed on the livestock production sector. Values of a net requirement estimated by the ARC (1981) extend from 4.6 g/day for 25kg liveweight to 5.2 g/day for 45kg pigs, but current literature suggesting that the actual requirement may be lower (eg Jongbloed and Everts, 1991) calls for a revision of previous recommendations.

Around two thirds of the total phosphorus in cereals exists in the form of insoluble phytates which must be degraded before the phosphorus can be absorbed in the intestine. Under experimental conditions, the use of phytase in pig diets has demonstrated consistent improvements in phosphorus digestibility. The enzyme hydrolyses phytate by stepwise removal of orthophosphates, which become available for absorption in the gut. Although quantification of phytase/phosphorus substitution is as yet undetermined, digestibility results so far indicate that if used correctly the enzyme could largely replace inorganic phosphates, particularly in regions where soil phosphate levels are of concern.

Stress can be reduced during transport and handling by training people to use behavioral principles when handling animals, selecting livestock with a calm temperament and using well designed handling facilities and vehicles. In the U.S., there are increasing problems with very excitable cattle and pigs which are very difficult to handle and drive. Gentle, quiet handling of excitable genetic lines of pigs in single file races in a high speed slaughter plant is extremely difficult. Excitable pigs are more easily distracted by small distractions such as a sparkling reflection on the floor and are more likely to balk and pile up. Some excitable genetic lines of pigs have greatly elevated death losses during transport. Excitable animals are more fearful of novel new situations than calmer genetic lines. Similar excitability problems are being observed in cattle. Excitable genetic lines of cattle are more likely to severely injure themselves or handlers during handling because they are more likely to panic when confronted with novelty. The author has observed cattle from excitable genetic lines that went into a total panic when they were in novel surroundings. Excitability problems are more likely to cause problems in the U.S. due to very extensive raising of cattle. Excitable cattle that are reared intensively become accustomed to people and vehicles and they are more tolerant of novel situations than excitable cattle reared on open rangeland where they seldom see people. Excitable genetic lines of cattle which are completely halter broken become trained to accept novelty and will usually remain calm, but when these same animals are raised extensively where they seldom see people, they often panic and injure themselves when they are brought to an auction market or slaughter plant. Breeders need to select animals that have a calm temperament. Recent research in our laboratory has shown that the position of the spiral hair whorls on the foreheads of beef cattle is related to temperament. Beef cattle with high hair whorls located above the eyes become more agitated during restraint in a squeeze chute compared to cattle with hair whorls located between or below the eyes. Indiscriminant selection for rapid growth and leanness has contributed to this problem. Excitable genetic lines of cattle and pigs are causing serious welfare problems during handling in the U.S.

Currently, in excess of 650 million broiler chickens are produced per annum in the UK.The rearing of these animals on large numbers of geographically dispered sites necessitates their transportation to centralised processing plants for slaughter. Birds are transported in containers in which behaviour, including any thermoregulatory component, will be restricted. The design of the container and the vehicle and the external climatic conditions will have profound effects upon the immediate environment of the birds. In transit they may be exposed to a variety of potential stressors including the thermal demands of this transport microenvironment, motion, acceleration, vibration, impacts, fasting, withdrawal of water, social disruption and noise. The adverse effects of these factors and their combinations may range from discomfort and mild aversion to death. Mortalities in transit are generally 0.4% or less but this may represent approximately 2 million birds per annum in the UK. It is estimated that up to 40% of the mortalities observed at the processing plant are a consequence of “stress”. It is thus essential from the standpoints of both animal welfare and productivity to optimise commercial poultry transport conditions and to provide the sound scientific basis for legislation relating to vehicles and transport practices. Although examination of the existing literature reveals that thermal stress is acknowledged as a major hazard during animal transportation it has been poorly characterised under practical conditions and the interactions between the animals and the complex thermal microenvironments clearly require more rigorous analyses.