CHAPTER 2 Five experiments were conducted to investigate the dietary factors within the rumen environment which could contribute to the rate of degradation of straw. Three sources of digestible cellulose and/or hemicellulose (unmolassed sugar beet pulp, citrus pulp and dried grass) and two sources of natural proteins (fish meal and soya bean meal) were investigated for their ability to increase degradation of straw In. sacco in sheep, as supplements to untreated straw. The untreated straw used in these experiments was adequately supplemented with rumen degradable nitrogen, sulphur, vitamins and minerals. Unmolassed sugar beet pulp and dried grass when given at a level of 150 g.kg DM-1, increased both the rate and extent of DM degradation of straw In sacco. Citrus pulp and soya bean meal had no effect on straw degradation while fish meal increased the extent of straw DM degradation. The rumen NH3 levels and pH in both the control and supplemented animals were above the range that would be expected to cause an inhibition in fibre digestion. It was concluded that digestible cellulose/hemicellulose and fish meal improved the conditions in the rumen for fibre degradation in animals given straw diets. CHAPTER 3 The supplementary effects of unmolassed sugar beet pulp and fish meal on intake, digestibility and growth performances of sheep, given either untreated or ammonia treated straw, were investigated using twenty four sheep. The experimental design was a 2 x 2 x 2 factorial layout. Unmolassed sugar beet pulp and fish meal increased untreated straw digestibility by 10% and intake by 16-22%. The supplements had no effect on the digestibility or intake of basal ammonia treated straw. Ammonia treatment alone however increased the intake and digestibility of untreated straw by 76% and 16%, respectively. The growth achieved in this experiment was highly correlated to the intake of total digestible DM. CHAPTER 4 Two experiments were conducted to study the supplementary effects of unmolassed sugar beet pulp and fish meal on intake, digestibility and growth performance of cattle given either untreated or ammonia treated straw. Twenty four Hereford x Friesian steers and thirty two Friesian cross steers and bulls were used for the two experiments respectively. The first experiment was conducted for ten weeks, while the second experiment was continued for twenty weeks. Both the experiments were of 2 x 2 x 2 factorial design. Unmolassed sugar beet pulp and fish meal when given in a combination increased the intake and digestibility of untreated straw. Similar to the results of the sheep experiment (Chapter 3) these supplements did not change the intake or digestibility of ammonia treated straw. Ammonia treatment however increased the intake by 22 and 2 and digestibility by 26 and 14% in these two experiments. The growth observed in the first experiment was higher than expected, but in both experiments growth was related to total digestible DM intake. CHAPTER 5. Methods to predict the rate and extent of roughage degradation in different rumen environments were investigated. The activities of two particle-bound microbial enzymes were measured, glutmate dehydrogenase (GDH) and carboxymethyl cellulase (CMCase). A method was developed and standardized to measure particle-bound microbial enzymes after incubating straw contained in nylon bags in the rumens of sheep given different diets. Using this method particle-bound enzyme activities were correlated with dry matter degradation in the rumen. Particle-bound NAD-linked GDH activity showed no relationship to dry matter degradation while particle-bound CMCase activity showed a very high correlation with the rate and extent of straw degradation. It was concluded that measuring particle-bound CMCase activity at 8 or 16 hr incubation periods could be useful in predicting the rate and extent of DM degradation of straw. CHAPTER 6 The results were discussed in relation to the view that the 'rate limiting: steps' that control digestion and intake of low quality roughages such as rate of fibre degradation, rate of particle size reduction, and the rate of passage of undigested material from the rumen depend upon: (a) proportion of the fibre-degrading organisms in the total microbial population (b) factors related to the roughage such as 'fragility' (c) animal species (i.e. sheep or cattle). Practical implications of the findings for animal production were evaluated on a nutritional and economical basis and it was concluded that the judicious supplementation of untreated straw with a source of digestible cellulosic/hemicellulosic material and a slowly degrading natural protein could replace ammonia treatment of straw, but has to be reassessed in different parts of the world depending on the availability and cost of the supplements.

The main objectives of the work described in this thesis were to determine the technical feasibility of utilising date palm leaves as a potential source of roughage, and to study the effects of providing brackish water as a source of drinking water for dairy cows. Additionally, to investigate the effect of feeding a high concentrate diet on the performance of Friesian cows. Four experiments were performed during the course of three years (November 1988 - June 1991). Three experiments were carried out in Kuwait and one in the North of Scotland. Experiment 1 was designed to compare the effects of feeding locally produced date palm leaves (DPL) with imported barley straw (S) as roughages to milking cows given a high concentrate diet. Fifty-six cows were used from the fifth week of lactation for 12 weeks. Experiment 2 studied the performance of thirty eight non-lactating pregnant cows for about 15 weeks, with the same objective as experiment 1. Each of these experiments included a small trial for more detailed studies. In experiment 3 eight milking cows in the sixth week of lactation were studied for over six months to compare the effects of drinking brackish water (BW) with fresh water (FW) on the performance of the cows fed on a high concentrate diet in addition to DPL and freshly cut alfalfa. Experiment 4 was conducted in the North of Scotland to investigate the effects of feeding a high concentrate diet, similar to that of Kuwait, on the productivity and the ruminal fermentation of high yielding cows. The general conclusions drawn from these four experiments are: 1. Despite the low qulaity of DPL, it might be a suitable alternative to straw as a source of roughage for dairy cows in Kuwait. 2. Brackish water is a palatable and harmless source of drinking water, and its mineral content may be beneficial in contributing to the dairy cows dietary requirements. 3. Feeding a high level of concentrate in diets based on grass silage increases milk yield and favours body gain at the expense of milk fat content. 4. There is a need for better utilization and processing of local agricultural by-products in Kuwait for the feeding of ruminants. 5. Further research is required to investigate the performance of dairy cows under different environments, especially hot-arid conditions.

Prior to giving birth, sows are normally confined in crates. One of the current aims in pig production is to develop an alternative farrowing system in which the sows are unconfined and grouped together. The aim of the new system is to improve the welfare of the sow and litter whilst maintaining high levels of productivity. Four studies were conducted to document the nest building and social behaviour of sows so that the system can be designed to suit their needs. The fifth study compared the productivity of unconfined individual and grouped sows with confined sows. Study 1. Six sows were housed in a pen which contained a sand floor and straw dispenser. Nine and a half hours before farrowing the sows displayed rooting, pawing and straw carrying and removed 23 kg straw to build a nest with hollow, straw lining and nest rim. Six sows were presented with similar nests. Nest building behaviour was affected by feeding behaviour. Study 2. Sixteen sows were presented with a hollow (H), a mattress (M), a nest box (B) which represented the 3 nest features and a control (C). Farrowing site preference was (H) 6, (M) 6, (B) 4 and (C) 0. In trial 2, (C) was replaced by a straw area (S), all 16 sows farrowed in (S) when it contained 4.5-18 kg straw. At 2.25 kg preference was (H) 1, (M) 3, (B) 1, (S) 3. Nest building behaviour was not affected by the amount of straw in (S).Study 3. Four previously confined and 3 unconfined sows were housed in a pen which included a straw (S), a central food (F) and a control (C) area. Entry into (S) and (C) was contingent on 10 panel presses. Food was delivered into (F) every 2 hours. The sows pressed the panel for (S) more than (C). Nest builidng behaviour was affected by feeding behaviour. Confined sows tended to show more behaviour associated with the straw. In trial 2, 5 sows were housed in pen which included a straw (S), a central (C) and a food (F) area. Cost of entry into (S) and (F) was gradually increased. Food was delivered into (F) every 45 mins. The fall in work rates for straw and food were similar as the cost was increased. The work rate for straw was increased 24 hours before farrowing. Study 4. Twenty-two sows were paired with an unfamiliar conspecific in pens which contained 2 strawed lying areas. As farrowing approached, the sows spent less time lying together and the aggressive behaviour of 12 dominant prepartal sows increased significantly. The level of aggression was significantly reduced in 11 dominant prepartal sows paired with unfamiliar conspecifics in modified pens and between 9 pairs of pre-partal sows which were familiar with each other. Sows were observed to lie together at farrowing and to farrow in more than one lying area. Study 5. Appetite and piglet mortality was compared for 43 sows in straw pens, 51 sows housed with pen-mates in straw pens and 50 sows in farrowing crates. Appetite was not reduced during the periparturient period or affected by pen type. There was no difference in the number of piglets which died during the first 24 hours after farrowing in the 3 pen types. Sows in farrowing crates tended to have more stillborn piglets.

No description available.

The aim of this study was to determine the optimal amino acid balance in dietary protein for the growing pig. The method used was based on the principle that removal of any amino acid in excess of that required in this amino acid pattern should not affect nitorgen retention. A semi-purified diet based on casein and amino acids was used in a series of experiments. A proportion of each amino acid was removed in turn from the control amino acid pattern to determine how much could be removed without affecting nitrogen retention. The effect of changing the ratio of essential: non-essential amino acid was also examined. From these experiments an ideal dietary amino acid pattern for growing pigs was determined. This pattern was utilized significantly better than that proposed by ARC(1981). The property that in such an ideal pattern each amino acid should be equally limiting was tested and confirmed in both short and long term nitrogen balance trials. In the final experiment, the optimum ratios between lysine, methionine, threonine and tryptophan at two different rates of growth were determined using diets based on maize and soya bean meal. It was found that less threonine was needed than was deduced from the experiment with semi-synthetic diets. From the results of all the experiments the following amino acid pattern (g/160gN) is suggested: lysine 65, methionine + cystine 39, threonine 43, tryptophan 12, valine 49, isoleucine 39, leucine 72, phenylalanine + tyrosine 78, histidine 25.

The relationship between dietary nutrient inputs, particularly energy and protein, and their partition between fibre, meat and other non-meat components in British fibre producing goats was studied in a series of four experiments. Experiment 1 indicated that increasing dietary energy concentration from 10.2 to 11.9 MJ ME/kg dry matter (DM) significantly (P &'60 0.05 to 0.001) improved liveweight gain, feed conversion efficiency, carcass weight, cross sectional area of M.longissimus dorsi , and increased fat thickness over N.serratus dorsalis . Values were also increased in the carcass for dissected lean tissue and crude protein, weights and proportions of dissected and chemically extractable fat, weights of liver, kidneys and also fat deposition in the omental and perirenal plus retro-peritoneal depots. No consistent effects due to dietary energy inputs were observed for yield and diameter of mohair fibres. Similarly, changing the dietary protein concentration from 108 to 180 g/kg DM resulted in significantly (P &'60 0.05 to P &'60 0.001) increased values for live weight gain, DM intake, feed conversion efficiency, carcass weight, killing out proportions, area, width and depth of M.longissimus dorsi , weights of dissected carcass lean tissue, chemically determined crude protein and lipid in the carcass and also greater yield and diameter of mohair fibres. The results of experiment 2 indicated that increasing dietary protein concentrations (102, 126, 165, 185 g/kg DM) by the inclusion of fish and soya bean meal increased (linear effect, P &'60 0.05 to P &'60 0.001) live weight gain, feed conversion efficiency, carcass weight, width of M.longissimus dorsi , weight and proportion of dissectible carcass lean tissue and weight of crude protein in the carcass, liver and kidneys. The clean fibre yield and diameter were increased as the dietary CP concentration increased from 102 to 165 g/kg DM and then decreased at the highest CP concentration of 185 g/kg DM. Experiment 3 showed that source of nitrogen supplementation (urea, fish meal or soya bean meal) had no significant effects on growth rate, DM intake, feed conversion efficiency and nitrogen balance. However, soya bean meal supplementation resulted in significantly (P &'60 0.05 to P &'60 0.001) higher values for nitrogen digestibility, carcass weight, killing out proportion, dissectible lean tissue with trends to increase area of M.longissimus dorsi and microbial protein synthesis. The yield and diameter of mohair fibre were increased (P &'60 0.05) due to protein supplementation compared with the NPN supplementation in the diet. Experiment 4 indicated that average growth rate, DM intake, feed conversion efficiency, carcass weight and killing out proportions were not significantly different for the source of nitrogen supplementation (urea v fish meal) or for the genotype of Cashmere goats (Russian v Australasian crosses). Mid-side fleece growth (Cashmere &'43 guard hair) was significantly (P &'60 0.05) higher in goats given fish meal rather than urea supplemented diet and Russian goats tended to produce higher proportion of cashmere in the mid-side and in total fleece samples than those of Australasian genotype.

The welfare of young pigs was compared in different housing systems using a range of indicators. Groups of twenty pigs were weaned at 6.4 kg into each of four pens built within environmentally-controlled rooms: a) deep-straw; b) Straw-Flow(R) (1 kg straw daily); c) large expanded metal-floored flatdeck; d) small flatdeck. Kennelled lying areas were provided in a and b. Stocking densities were 0.229 m2/pig for a,b and c, and 0.173 m2/pig for d. After 4-5 weeks (19.6 kg liveweight), sixteen pigs from each pen were moved into Straw-Flow grower pens (0.675 m2/pig) and observed until slaughter at 90.6 kg. The remaining pigs were grouped together to examine the effects of mixing. Housing type did not affect growth and feed intake. Food conversion ratio was poorer in large flatdeck than in small flatdeck or Straw-Flow. Behavioural differences between Straw-Flow and deep-straw related to differences in available straw; there were few differences between flatdecks. Access to straw affected pig-directed, pen-directed and straw-directed behaviours. Foot injuries recovered rapidly on deep-straw and increased in flatdecks immediately after weaning (Straw-Flow intermediate); injuries were more persistent in small flatdeck. Deep-straw prevented adventitious bursitis of the hock. Antibody response was examined by challenge with keyhole limpet haemocyanin (KLH). Immunoglobulin (Ig) M response was greater in straw pens. Dust concentration was higher in kennelled lying areas than flatdecks. With removal of kennels, straw pens showed less dust than flatdecks. Thus, welfare of early-weaned pigs in deep-straw was very good, flatdecks poor with Straw-Flow closer to deep-straw than to flatdecks. Early experience had limited effects. Pigs from flatdecks performed increased rooting relative to deep-straw two weeks after moving (Straw-Flow intermediate). These differences did not persist. Pigs mixed at 20 kg showed increased aggression (not significant) and decreased Ig m response to KLH, indicating reduced welfare.

Three studies were conducted on commercial farms. Study 1 sought to compare four combinations of natural mating (NM) and AI, namely AI + AI, AI + NM, NM + AI and NM + NM (first mating on day 1 of oestrous and second on day 2), and evaluate what aspects of insemination quality are related to fertility. The respective farrowing rates (FR) of AI + AI, AI + NS, NS + AI and NS + NS were (number of sows in parentheses) 92.9% (141), 89.6% (134), 89.3% (140) and 89.0% (100) and litter size (LS) was 11.31, 10.49, 11.50 and 10.61 (total births). The number of pigs born per 100 sows mated were 1051, 940, 1027 and 944. Both FR (P < 0.05) and LS (P < 0.01) were significantly influenced by parity. Sow behaviour during insemination significantly influenced (P < 0.01) FR and LS, the mean FR of calm and agitated sows being 91.3 and 83.1 percent and the mean LS being 11.32 and 10.22 respectively. Loss of semen due to backflow during insemination significantly reduced (P < 0.05) FR in sows having one AI. Backflow losses were significantly lower (P < 0.01) in calm than in agitated sows. It was concluded that AI, either alone or in combination with NM, yields fertility results comparable to NM alone and that sow behaviour during insemination has an important effect on sow fertility. Study 2 tested the effect of the addition of 5 i.u. of oxytocin to semen immediately before AI on fertility at two farms. Overall oxytoxin significantly improved FR (P < 0.05) from 73.2 percent (429) to 79.5 percent (385) and substantially improved litter size from 10.70 to 11.18. There was a significant (P < 0.05) treatment x farm interaction, FR on farm A improving from 77.2% (control) to 78.0% (oxytocin) whereas FR on farm B improved from 69.7% (control) to 84.0% (oxytocin). It was hypothesised that differences between farms in operator skill during insemination may have mediated the differing response to oxytocin.

The protein requirements and nutrition of bulls intensively reared on barley were investigated in the light of current knowledge of protein metabolism in the ruminant. Five experiments were carried out using cattle and sheep. 1. The response of barley beef bulls to RDP and UDP supplementation was examined. Although results were not significantly different, urea supplemented diets gave the highest growth rates of 1.45 and 1.47 kg/d; soya bean meal supplemented diets gave growth rates of 1.31 and 1.36 kg/d while the unsupplemented barley diet gave a growth rate of 1.23 kg/d. Feed conversion ratios ranged from 5.89 to 6.51. 2. The response of barley beef bulls to barleys of different protein content and degradability and to RDP and UDP supplementation was examined. Results were not significantly different although the high protein, low dg barley gave slightly lower liveweight gains (1.29 and 1.24 kg/d) than the low protein, high dg barley (1.32, 1.33 and 1.34 kg/d). RDP and UDP supplementation gave no additional growth response on any of the diets. Feed conversion ratios were approximately the same as the first trial ranging from 6.08 to 6.65. 3. A study of the barley-beef diets used in the first bull trial was carried out using surgically modified sheep fitted with Ash-type re-entrant cannulae in the duodenum. Five of the six animals died shortly after surgery and it was concluded that the surgery, and the type of cannulae used were a major factor causing this. 4. A study of the barley-beef diets used in the second bull trial was carried out using surgically modified sheep fitted with Hecker-type re-entrant cannulae. 24 h duodenal digesta collections with Cr2O3 as a marker were carried out followed by 7 d nitrogen balance and digestibility trials. Results obtained were nullified by incomplete marker recovery and it was concluded that the Hecker-type of re-entrant cannulae may be unsuitable for total digesta collection. The low protein, high dg barley diets were more digestible than the other barley diets and it was suggested that this may have improved rate of microbial synthesis in the bulls fed on these diets. 5. A study was carried out to examine certain factors affecting the degradability of barley as determined by the nylon bag technique. Variety, CP content and nitrogen fertiliser treatment were studied. Variety had a significant effect on dg (0.15-0.42), malting varieties being more degradable. Degradability tended to decrease as nitrogen fertiliser level increased (0.06-0.23). There also seemed to be a general trend that as CP content increased, dg decreased (0.6-0.8). The results were discussed in relation to current knowledge of ruminant protein metabolism. The new ARC protein system was shown to be acceptable as a framework and the need for more practical data was emphasised.

The genetic outcome of operating an open nucleus system (ONS) in a population of 1200 sheep divided into individual flocks, was investigatd using simulation techniques, and a comparison to alternative breeding systems was made. Selection was for best linear unbiased prediction of breeding value (EBV) for a trait measurable on individuals before selection. Migration of animals between flocks was based on the EBV. The results of stochastic simulations indicated that, compared to selection within closed flocks (CF), the annual genetic gain could be increased by 25 to 40 per cent if an ONS was operated. The variation in selection response, and the rate of inbreeding were also lower. Simulation results showed that approximately 25 per cent of nucleus sires should be selected from the base flocks. Initial genetic differences between flocks had a short term effect on genetic gain in the ONS. Screening the population to ensure that the nucleus flock was initially composed of the best ewes, also only had a short term effect. The advantage of an ONS over CF selection was effected by flock size but not intitial heritability. The use of dispersed nucleus system and a sire referencing scheme with selection of sires across flocks, was investigated. The outcome of these systems was very similar to the ONS. The higher rate of genetic gain achieved in the ONS, compared to CF selection, was attributed to higher genetic selection differentials and maintenance of genetic variation within flocks. These effects were included in a deterministic model of the ONS. The model described the simulated data well, although changes in genetic variance at the outset of the ONS were underestimated. Failure to account for finite population effects in previous studies has resulted in underestimation of the benefits of an open nucleus system in small populations.